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  1. DRY NEEDLING INCREASES MUSCLE THICKNESS IN A SUBJECT WITH PERSISTENT MUSCLE DYSFUNCTION: A CASE REPORT.

    Science.gov (United States)

    Cross, Kevin M; McMurray, Michael

    2017-06-01

    Muscle dysfunction is very common following musculoskeletal injury. There is very little evidence to suggest that muscle function may be positively impacted by soft tissue interventions, such as dry needling. The purpose of this case report is to describe the immediate effect of dry needling on muscle thickness in a subject after shoulder surgery. A 22 year-old competitive gymnast presented seven months post shoulder surgery with significant impairments and functional limitations. Previous physical therapy focused on restoration of range of motion and strength using general exercise interventions, but the subject had persistent tightness and weakness of musculature of the shoulder complex. A subject-specific physical therapy program including manual physical therapy resulted in significant initial improvement, but lack of flexibility and weakness of the rotator cuff limited progress. Dry needling was used to address persistent myofascial trigger points. Immediately after dry needling the infraspinatus, the muscle's thickness was significantly improved as measured by rehabilitative ultrasound imaging. There was a corresponding increase in force production of external rotation at 90 degrees of abduction. Minimal research exists that validates the potential of dry needling on muscle function, as assessed by muscle thickness measured using rehabilitative ultrasound imaging. The results of this case report suggest that dry needling contributed to improvement in muscle thickness and strength in a subject with muscle dysfunction following an injury. 4.

  2. Antagonist muscle moment is increased in ACL deficient subjects during maximal dynamic knee extension

    DEFF Research Database (Denmark)

    Alkjær, Tine; Simonsen, Erik B; Magnusson, S Peter

    2012-01-01

    INTRODUCTION: Coactivation of the hamstring muscles during dynamic knee extension may compensate for increased knee joint laxity in anterior cruciate ligament (ACL) deficient subjects. This study examined if antagonist muscle coactivation during maximal dynamic knee extension was elevated...... in subjects with anterior cruciate ligament (ACL) deficiency compared to age-matched healthy controls. METHODS: Electromyography (EMG) and net knee joint moments were recorded during maximal concentric quadriceps and eccentric hamstring contractions, performed in an isokinetic dynamometer (ROM: 90......-10°, angular speed: 30°/s). Hamstring antagonist EMG recorded during concentric quadriceps contraction was converted into antagonist moment based on the EMG-moment relationship observed during eccentric agonist contractions. RESULTS: The magnitude of antagonist hamstring EMG was 65.5% higher in ACL deficient...

  3. Fibre type-specific increase in passive muscle tension in spinal cord-injured subjects with spasticity

    Science.gov (United States)

    Olsson, M Charlotte; Krüger, Martina; Meyer, Lars-Henrik; Ahnlund, Lena; Gransberg, Lennart; Linke, Wolfgang A; Larsson, Lars

    2006-01-01

    Patients with spasticity typically present with an increased muscle tone that is at least partly caused by an exaggerated stretch reflex. However, intrinsic changes in the skeletal muscles, such as altered mechanical properties of the extracellular matrix or the cytoskeleton, have been reported in response to spasticity and could contribute to hypertonia, although the underlying mechanisms are poorly understood. Here we examined the vastus lateralis muscles from spinal cord-injured patients with spasticity (n = 7) for their passive mechanical properties at three different levels of structural organization, in comparison to healthy controls (n = 7). We also assessed spasticity-related alterations in muscle protein expression and muscle ultrastructure. At the whole-muscle level in vivo, we observed increased passive tension (PT) in some spasticity patients particularly at long muscle lengths, unrelated to stretch reflex activation. At the single-fibre level, elevated PT was found in cells expressing fast myosin heavy chain (MyHC) isoforms, especially MyHC-IIx, but not in those expressing slow MyHC. Type IIx fibres were present in higher than normal proportions in spastic muscles, whereas type I fibres were proportionately reduced. At the level of the isolated myofibril, however, there were no differences in PT between patients and controls. The molecular size of the giant protein titin, a main contributor to PT, was unchanged in spasticity, as was the titin:MyHC ratio and the relative desmin content. Electron microscopy revealed extensive ultrastructural changes in spastic muscles, especially expanded connective tissue, but also decreased mitochondrial volume fraction and appearance of intracellular amorphous material. Results strongly suggest that the global passive muscle stiffening in spasticity patients is caused to some degree by elevated PT of the skeletal muscles themselves. We conclude that this increased PT component arises not only from extracellular matrix

  4. A whey-protein supplement increases fat loss and spares lean muscle in obese subjects: a randomized human clinical study

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    Ward Loren S

    2008-03-01

    Full Text Available Abstract Background This study evaluated a specialized whey fraction (Prolibra™, high in leucine, bioactive peptides and milk calcium for use as a dietary supplement to enhance weight loss. Methods This was a randomized, double-blind, parallel-arm, 12-week study. Caloric intake was reduced 500 calories per day. Subjects consumed Prolibra or an isocaloric ready-to-mix beverage 20 minutes before breakfast and 20 minutes before dinner. Body fat and lean muscle tissue were measured by dual-energy x-ray absorptiometry (DEXA. Body weight and anthropometric measurements were recorded every 4 weeks. Blood samples were taken at the beginning and end of the study. Statistical analyses were performed on all subjects that completed (completer analysis and all subjects that lost at least 2.25 kg of body weight (responder analysis. Within group significance was determined at P Results Both groups lost a significant amount of weight and the Prolibra group tended to lose more weight than the control group; however the amount of weight loss was not significantly different between groups after 12 weeks. Prolibra subjects lost significantly more body fat compared to control subjects for both the completer (2.81 vs. 1.62 kg P = 0.03 and responder (3.63 vs. 2.11 kg, P = 0.01 groups. Prolibra subjects lost significantly less lean muscle mass in the responder group (1.07 vs. 2.41 kg, P = 0.02. The ratio of fat to lean loss (kg fat lost/kg lean lost was much larger for Prolibra subjects for both completer (3.75 vs. 1.05 and responder (3.39 vs. 0.88 groups. Conclusion Subjects in both the control and treatment group lost a significant amount of weight with a 500 calorie reduced diet. Subjects taking Prolibra lost significantly more body fat and showed a greater preservation of lean muscle compared to subjects consuming the control beverage. Because subjects taking Prolibra lost 6.1% of their body fat mass, and because a 5% reduction of body fat mass has been shown to

  5. Increased probability of repetitive spinal motoneuron activation by transcranial magnetic stimulation after muscle fatigue in healthy subjects

    DEFF Research Database (Denmark)

    Andersen, Birgit; Felding, Ulrik Ascanius; Krarup, Christian

    2012-01-01

    Triple stimulation technique (TST) has previously shown that transcranial magnetic stimulation (TMS) fails to activate a proportion of spinal motoneurons (MNs) during motor fatigue. The TST response depression without attenuation of the conventional motor evoked potential suggested increased prob...... the muscle is fatigued. Repetitive MN firing may provide an adaptive mechanism to maintain motor unit activation and task performance during sustained voluntary activity.......Triple stimulation technique (TST) has previously shown that transcranial magnetic stimulation (TMS) fails to activate a proportion of spinal motoneurons (MNs) during motor fatigue. The TST response depression without attenuation of the conventional motor evoked potential suggested increased...... probability of repetitive spinal MN activation during exercise even if some MNs failed to discharge by the brain stimulus. Here we used a modified TST (Quadruple stimulation; QuadS and Quintuple stimulation; QuintS) to examine the influence of fatiguing exercise on second and third MN discharges after...

  6. Dietary intervention increases n-3 long-chain polyunsaturated fatty acids in sceletal muscle membrane phospholipids of obese subjects. Inplications for insulin sensitivity

    DEFF Research Database (Denmark)

    Haugaard, Steen B; Madsbad, Sten; Høy, C-E

    2006-01-01

    OBJECTIVE: Cross-sectional studies suggest that the fatty acid (FA) composition of phospholipids in skeletal muscle cell membrane may modulate insulin sensitivity in humans. We examined the impact of a hypocaloric low-fat dietary intervention on membrane FA composition and insulin sensitivity....... DESIGN Muscle membrane FA profiles were determined in muscle (vastus lateralis) biopsies from 21 obese subjects before and after 6 months of dietary restriction. Diet instructions emphasized low intake of FA of marine origin by recommending lean fish and prohibiting fatty fish and fish oil supplements......-chain PUFAn-3 increased 51% (P= 0.0001), mainly due to a 75% increase (Pacid. Changes in HOMA-IR correlated significantly with changes in long-chain PUFAn-3 (R=-0.57, P

  7. Dietary intervention increases n-3 long-chain polyunsaturated fatty acids in skeletal muscle membrane phospholipids of obese subjects. Implications for insulin sensitivity

    DEFF Research Database (Denmark)

    Haugaard, S.B.; Madsbad, S.; Høy, Carl-Erik

    2006-01-01

    Objective Cross-sectional studies suggest that the fatty acid (FA) composition of phospholipids in skeletal muscle cell membrane may modulate insulin sensitivity in humans. We examined the impact of a hypocaloric low-fat dietary intervention on membrane FA composition and insulin sensitivity....... Design Muscle membrane FA profiles were determined in muscle (vastus lateralis) biopsies from 21 obese subjects before and after 6 months of dietary restriction. Diet instructions emphasized low intake of FA of marine origin by recommending lean fish and prohibiting fatty fish and fish oil supplements......-chain PUFAn-3 increased 51% (P = 0.0001), mainly due to a 75% increase (P acid. Changes in HOMA-IR correlated significantly with changes in long-chain PUFAn-3 (R = -0.57, P

  8. Branched-chain amino acids increase arterial blood ammonia in spite of enhanced intrinsic muscle ammonia metabolism in patients with cirrhosis and healthy subjects

    DEFF Research Database (Denmark)

    Dam, Gitte; Keiding, Susanne; Munk, Ole Lajord

    2011-01-01

    metabolism of ammonia and amino acids in 14 patients with cirrhosis and in 7 healthy subjects by combining [(13)N]ammonia positron emission tomography (PET) of the thigh muscle with measurements of blood flow and arteriovenous (A-V) concentrations of ammonia and amino acids. PET was used to measure...... the metabolism of blood-supplied ammonia and the A-V measurements were used to measure the total ammonia metabolism across the thigh muscle. After intake of BCAA, blood ammonia increased more than 30% in both groups of subjects (both P PET) was unaffected (P...... = 0.75), but the metabolic removal rate (PET) increased significantly because of increased blood ammonia in both groups (all P

  9. Protein Supplementation Does Not Further Increase Latissimus Dorsi Muscle Fiber Hypertrophy after Eight Weeks of Resistance Training in Novice Subjects, but Partially Counteracts the Fast-to-Slow Muscle Fiber Transition

    Directory of Open Access Journals (Sweden)

    Antonio Paoli

    2016-06-01

    Full Text Available The response to resistance training and protein supplementation in the latissimus dorsi muscle (LDM has never been investigated. We investigated the effects of resistance training (RT and protein supplementation on muscle mass, strength, and fiber characteristics of the LDM. Eighteen healthy young subjects were randomly assigned to a progressive eight-week RT program with a normal protein diet (NP or high protein diet (HP (NP 0.85 vs. HP 1.8 g of protein·kg−1·day−1. One repetition maximum tests, magnetic resonance imaging for cross-sectional muscle area (CSA, body composition, and single muscle fibers mechanical and phenotype characteristics were measured. RT induced a significant gain in strength (+17%, p < 0.0001, whole muscle CSA (p = 0.024, and single muscle fibers CSA (p < 0.05 of LDM in all subjects. Fiber isometric force increased in proportion to CSA (+22%, p < 0.005 and thus no change in specific tension occurred. A significant transition from 2X to 2A myosin expression was induced by training. The protein supplementation showed no significant effects on all measured outcomes except for a smaller reduction of 2X myosin expression. Our results suggest that in LDM protein supplementation does not further enhance RT-induced muscle fiber hypertrophy nor influence mechanic muscle fiber characteristics but partially counteracts the fast-to-slow fiber shift.

  10. Effects of an exercise program to increase hip abductor muscle strength and improve lateral stability following stroke: a single subject design.

    Science.gov (United States)

    Mercer, Vicki S; Chang, Shuo-Hsiu; Williams, Cherie D; Noble, Kelli; Vance, Anthony W

    2009-01-01

    Persons with lower extremity weakness following stroke often demonstrate difficulty with weight transfer and paretic lower extremity loading. These deficits, in turn, can lead to problems with lateral stability, or the ability to control movement of the center of mass in the frontal plane. The primary aim of this study was to examine the efficacy of an individualized home exercise program in improving hip abductor muscle strength and lateral stability in a subject with chronic stroke. An A-B-A treatment-withdrawal single-subject design was used. The subject was a 70-year-old male who had experienced a left hemispheric stroke 36 months prior to initiation of the study. Bilateral hip abductor muscle strength, single limb stance (SLS), timed 360 degrees turn, Step Test, and 10-m walk at self-selected and fast speeds were recorded at regular intervals during the baseline (A-I), treatment (B), and treatment-withdrawal (A-2) phases. The home exercise program in the B phase consisted of lower extremity weight bearing and weight transfer activities and exercise on a lateral training device 3 to 5 times a week for 6 weeks. The Berg Balance Scale (BBS) and Stroke Impact Scale (SIS) were administered at the completion of each phase and at 6-week follow-up. Data were analyzed using visual analysis and the split-middle method of trend estimation. Mean levels of all measures improved from A-1 to B phases, with significant increases in trend for hip abductor muscle strength and SLS bilaterally. Most improvements were maintained during the treatment-withdrawal (A-2) phase and at follow-up. A home exercise program that includes exercise on a lateral training device shows promise for producing increases in hip abductor muscle strength and accompanying improvements in some measures of physical performance and disability in persons with chronic stroke.

  11. Dietary intervention increases n-3 long-chain polyunsaturated fatty acids in sceletal muscle membrane phospholipids of obese subjects. Inplications for insulin sensitivity

    DEFF Research Database (Denmark)

    Haugaard, Steen B; Madsbad, Sten; Høy, C-E

    2006-01-01

    . DESIGN Muscle membrane FA profiles were determined in muscle (vastus lateralis) biopsies from 21 obese subjects before and after 6 months of dietary restriction. Diet instructions emphasized low intake of FA of marine origin by recommending lean fish and prohibiting fatty fish and fish oil supplements....... Insulin resistance was estimated by the homeostasis model assessment (HOMA-IR). RESULTS The mean weight loss was 5.1 kg (range -15.3 to +1.3 kg). BMI decreased from 36.5 to 34.9 kg/m(2) (P=0.003). Saturated FA (SFA) decreased 11% (P=0.0001). Polyunsaturated FA (PUFA)n-6 increased 4% (P =0.003). Long...

  12. Increased muscle perfusion reduces muscle sympathetic nerve activity during handgripping

    NARCIS (Netherlands)

    Joyner, M. J.; Wieling, W.

    1993-01-01

    This study sought to determine whether increasing blood flow to active muscles can blunt the normal rise in muscle sympathetic nerve activity (MSNA) during heavy rhythmic forearm exercise in humans. Subjects performed 5- to 6-min exercise bouts of handgripping (30/min) at 40-50% of maximum voluntary

  13. Paraplegia increases skeletal muscle autophagy.

    Science.gov (United States)

    Fry, Christopher S; Drummond, Micah J; Lujan, Heidi L; DiCarlo, Stephen E; Rasmussen, Blake B

    2012-11-01

    Paraplegia results in significant skeletal muscle atrophy through increases in skeletal muscle protein breakdown. Recent work has identified a novel SIRT1-p53 pathway that is capable of regulating autophagy and protein breakdown. Soleus muscle was collected from 6 male Sprague-Dawley rats 10 weeks after complete T4-5 spinal cord transection (paraplegia group) and 6 male sham-operated rats (control group). We utilized immunoblotting methods to measure intracellular proteins and quantitative real-time polymerase chain reaction to measure the expression of skeletal muscle microRNAs. SIRT1 protein expression was 37% lower, and p53 acetylation (LYS379) was increased in the paraplegic rats (P paraplegia group compared with controls (P paraplegia appears to increase skeletal muscle autophagy independent of SIRT1 signaling. We conclude that chronic paraplegia may cause an increase in autophagic cell death and negatively impact skeletal muscle protein balance. Copyright © 2012 Wiley Periodicals, Inc.

  14. Decreased Thioredoxin-1 and Increased HSP90 Expression in Skeletal Muscle in Subjects with Type 2 Diabetes or Impaired Glucose Tolerance

    Directory of Open Access Journals (Sweden)

    M. Venojärvi

    2014-01-01

    Full Text Available In diabetes, the endogenous defence systems are overwhelmed, causing various types of stress in tissues. In this study, newly diagnosed or diet-treated type 2 diabetics (T2D (n=10 were compared with subjects with impaired glucose tolerance (IGT (n=8. In both groups, at resting conditions, blood samples were drawn for assessing metabolic indices and skeletal muscle samples (m. vastus lateralis were taken for the measurements of cellular defence markers: thioredoxin-1 (TRX-1 and stress proteins HSP72, HSP90. The protein level of TRX-1 was 36.1% lower (P=0.031 and HSP90 was 380% higher (P<0.001 in the T2D than in the IGT subjects, with no significant changes in HSP72. However, after the adjustment of both analyses with HOMA-IR only HSP90 difference remained significant. In conclusion, level of TRX-1 in skeletal muscle tissue was lower while that of HSP90 was higher in T2D than in IGT subjects. This may impair antioxidant defence and lead to disruptions of protein homoeostasis and redox regulation of cellular defences. Because HSP90 may be involved in sustaining functional insulin signalling pathway in type 2 diabetic muscles and higher HSP90 levels can be a consequence of type 2 diabetes, our results are potentially important for the diabetes research.

  15. Dietary intervention increases n-3 long-chain polyunsaturated fatty acids in sceletal muscle membrane phospholipids of obese subjects. Inplications for insulin sensitivity

    DEFF Research Database (Denmark)

    Haugaard, Steen B; Madsbad, Sten; Høy, C-E

    2006-01-01

    OBJECTIVE: Cross-sectional studies suggest that the fatty acid (FA) composition of phospholipids in skeletal muscle cell membrane may modulate insulin sensitivity in humans. We examined the impact of a hypocaloric low-fat dietary intervention on membrane FA composition and insulin sensitivity....... Insulin resistance was estimated by the homeostasis model assessment (HOMA-IR). RESULTS The mean weight loss was 5.1 kg (range -15.3 to +1.3 kg). BMI decreased from 36.5 to 34.9 kg/m(2) (P=0.003). Saturated FA (SFA) decreased 11% (P=0.0001). Polyunsaturated FA (PUFA)n-6 increased 4% (P =0.003). Long...... that included changes in weight, fat mass, waist circumference, plasma lipids, PUFA, SFA and long-chain PUFAn-3 indicated that SFA and long-chain PUFAn-3 were independent predictors of HOMA-IR (R(2)=0.33, Pfat dietary intervention programme increased incorporation of long...

  16. Emerin increase in regenerating muscle fibers

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    S Squarzoni

    2009-06-01

    Full Text Available The fate of emerin during skeletal muscle regeneration was investigated in an animal model by means of crush injury. Immunofluorescence, immunoblotting and mRNA analysis demonstrated that emerin level is increased in regenerating rat muscle fibers with respect to normal mature myofibers. This finding suggests an involvement of emerin during the muscle fiber regeneration process, in analogy with its reported involvement in muscle cell differentiation in vitro. The impairment of skeletal muscle physiological regeneration or reorganization could be a possible pathogenetic mechanism for Emery Dreifuss muscular dystrophy.

  17. Increased muscle glucose uptake during contractions

    DEFF Research Database (Denmark)

    Ploug, Thorkil; Galbo, Henrik; Richter, Erik

    1984-01-01

    We reinvestigated the prevailing concept that muscle contractions only elicit increased muscle glucose uptake in the presence of a so-called "permissive" concentration of insulin (Berger et al., Biochem. J. 146: 231-238, 1975; Vranic and Berger, Diabetes 28: 147-163, 1979). Hindquarters from rats...... in severe ketoacidosis were perfused with a perfusate containing insulin antiserum. After 60 min perfusion, electrical stimulation increased glucose uptake of the contracting muscles fivefold. Also, subsequent contractions increased glucose uptake in hindquarters from nondiabetic rats perfused for 1.5 h......-methylglucose uptake increased during contractions and glucose uptake was negative at rest and zero during contractions. An increase in muscle transport and uptake of glucose during contractions does not require the presence of insulin. Furthermore, glucose transport in contracting muscle may only increase if glycogen...

  18. Effects of Inspiratory and Expiratory Muscle Training in Normal Subjects

    OpenAIRE

    Sasaki, Makoto; Kurosawa, Hajime; Kohzuki, Masahiro

    2005-01-01

    The present study aimed to clarify the effects of inspiratory muscle training (IMT) and expiratory muscle training (EMT) on ventilatory muscle strength, pulmonary function and responses during exercise testing. Young healthy women were randomly assigned to 3 groups: IMT (n=16); EMT (n=16); or untrained normal controls (NC, n=8). Subjects in the IMT and EMT groups trained for 15 minutes twice daily over 2 weeks at loads of 30% maximal inspiratory and expiratory muscle strength, respectively. V...

  19. Endurance training enhances skeletal muscle interleukin-15 in human male subjects

    DEFF Research Database (Denmark)

    Rinnov, Anders; Yfanti, Christina; Nielsen, Søren

    2014-01-01

    endurance running. With the present study we aimed to determine if muscular IL-15 production would increase in human male subjects following 12 weeks of endurance training. In two different studies we obtained plasma and muscle biopsies from young healthy subjects performing: (1) 12 weeks of ergometer...... weeks of regular endurance training induced a 40% increase in basal skeletal muscle IL-15 protein content (p......Regular endurance exercise promotes metabolic and oxidative changes in skeletal muscle. Overexpression of interleukin-15 (IL-15) in mice exerts similar metabolic changes in muscle as seen with endurance exercise. Muscular IL-15 production has been shown to increase in mice after weeks of regular...

  20. Changes in Predicted Muscle Coordination with Subject-Specific Muscle Parameters for Individuals after Stroke

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    Brian A. Knarr

    2014-01-01

    Full Text Available Muscle weakness is commonly seen in individuals after stroke, characterized by lower forces during a maximal volitional contraction. Accurate quantification of muscle weakness is paramount when evaluating individual performance and response to after stroke rehabilitation. The objective of this study was to examine the effect of subject-specific muscle force and activation deficits on predicted muscle coordination when using musculoskeletal models for individuals after stroke. Maximum force generating ability and central activation ratio of the paretic plantar flexors, dorsiflexors, and quadriceps muscle groups were obtained using burst superimposition for four individuals after stroke with a range of walking speeds. Two models were created per subject: one with generic and one with subject-specific activation and maximum isometric force parameters. The inclusion of subject-specific muscle data resulted in changes in the model-predicted muscle forces and activations which agree with previously reported compensation patterns and match more closely the timing of electromyography for the plantar flexor and hamstring muscles. This was the first study to create musculoskeletal simulations of individuals after stroke with subject-specific muscle force and activation data. The results of this study suggest that subject-specific muscle force and activation data enhance the ability of musculoskeletal simulations to accurately predict muscle coordination in individuals after stroke.

  1. Optimization of Spinal Muscular Atrophy subject's muscle activity during gait

    Science.gov (United States)

    Umat, Gazlia; Rambely, Azmin Sham

    2014-06-01

    Spinal Muscular Atrophy (SMA) is a hereditary disease related muscle nerve disorder caused by degeneration of the anterior cells of the spinal cord. SMA is divided into four types according to the degree of seriousness. SMA patients show different gait with normal people. Therefore, this study focused on the effects of SMA patient muscle actions and the difference that exists between SMA subjects and normal subjects. Therefore, the electromyography (EMG) test will be used to track the behavior of muscle during walking and optimization methods are used to get the muscle stress that is capable of doing the work while walking. Involved objective function is non-linear function of the quadratic and cubic functions. The study concludes with a comparison of the objective function using the force that sought to use the moment of previous studies and the objective function using the data obtained from EMG. The results shows that the same muscles, peroneus longus and bisepsfemoris, were used during walking activity by SMA subjects and control subjects. Muscle stress force best solution achieved from part D in simulation carried out.

  2. Kinesthetic imagery training of forceful muscle contractions increases brain signal and muscle strength.

    Science.gov (United States)

    Yao, Wan X; Ranganathan, Vinoth K; Allexandre, Didier; Siemionow, Vlodek; Yue, Guang H

    2013-01-01

    The purpose of this study was to compare the effect of training using internal imagery (IMI; also known as kinesthetic imagery or first person imagery) with that of external imagery (EMI; also known as third-person visual imagery) of strong muscle contractions on voluntary muscle strengthening. Eighteen young, healthy subjects were randomly assigned to one of three groups (6 in each group): internal motor imagery (IMI), external motor imagery (EMI), or a no-practice control (CTRL) group. Training lasted for 6 weeks (~15 min/day, 5 days/week). The participants' right arm elbow-flexion strength, muscle electrical activity, and movement-related cortical potential (MRCP) were evaluated before and after training. Only the IMI group showed significant strength gained (10.8%) while the EMI (4.8%) and CTRL (-3.3%) groups did not. Only the IMI group showed a significant elevation in MRCP on scalp locations over both the primary motor (M1) and supplementary motor cortices (EMI group over M1 only) and this increase was significantly greater than that of EMI and CTRL groups. These results suggest that training by IMI of forceful muscle contractions was effective in improving voluntary muscle strength without physical exercise. We suggest that the IMI training likely strengthened brain-to-muscle (BTM) command that may have improved motor unit recruitment and activation, and led to greater muscle output. Training by IMI of forceful muscle contractions may change the activity level of cortical motor control network, which may translate into greater descending command to the target muscle and increase its strength.

  3. KINESTHETIC IMAGERY TRAINING OF FORCEFUL MUSCLE CONTRACTIONS INCREASES BRAIN SIGNAL AND MUSCLE STRENGTH

    Directory of Open Access Journals (Sweden)

    Wan X Yao

    2013-09-01

    Full Text Available The purpose of this study was to compare the effect of training using internal imagery (IMI; also known as kinesthetic imagery or first person imagery with that of external imagery (EMI; also known as third-person visual imagery of strong muscle contractions on voluntary muscle strengthening. Eighteen young, healthy subjects were randomly assigned to one of three groups (6 in each group: internal motor imagery (IMI, external motor imagery (EMI, or a no-practice control (CTRL group. Training lasted for 6 weeks (~15 min/day, 5 days/week. The participants’ right arm elbow-flexion strength, muscle electrical activity and movement-related cortical potential (MRCP were evaluated before and after training. Only the IMI group showed significant strength gained (10.8% while the EMI (4.8% and CTRL (-3.3% groups did not. Only the IMI group showed a significant elevation in MRCP on scalp locations over both the primary motor (M1 and supplementary motor cortices (EMI group over M1 only and this increase was significantly greater than that of EMI and CTRL groups. These results suggest that training by IMI of forceful muscle contractions was effective in improving voluntary muscle strength without physical exercise. We suggest that the IMI training likely strengthened brain-to-muscle (BTM command that may have improved motor unit recruitment and activation, and led to greater muscle output. Training by internal motor imagery of forceful muscle contractions may change the activity level of cortical motor control network, which may translate into greater descending command to the target muscle and increase its strength.

  4. Activation of rectus capitis posterior major muscles during voluntary retraction of the head in asymptomatic subjects.

    Science.gov (United States)

    Hallgren, Richard C; Rowan, Jacob J; Bai, Peng; Pierce, Steven J; Shafer-Crane, Gail A; Prokop, Lawrence L

    2014-01-01

    The purpose of this study was to assess levels of electromyographic activity measured from rectus capitis posterior major (RCPM) muscles of asymptomatic subjects as their heads moved from a self-defined neutral position to a retracted position. A 2 × 2 within-subjects factorial research design was used. Disposable, intramuscular electrodes were used to collect electromyographic data from asymptomatic subjects between the ages of 20 and 40 years old. Data analysis was performed using mixed effects β regression models. Activation of RCPM muscles was found to significantly increase (P < .0001) as the head moved from a self-defined neutral position to a retracted position. Rectus capitis posterior major muscle activation levels, measured as a function of head position, have not been previously reported. The findings from this study showed that RCPM muscle activation significantly increases during voluntary retraction of the head. Copyright © 2014 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

  5. Force steadiness, muscle activity, and maximal muscle strength in subjects with subacromial impingement syndrome

    DEFF Research Database (Denmark)

    Bandholm, Thomas; Rasmussen, Lars; Aagaard, Per

    2006-01-01

    physically active in spite of shoulder pain and nine healthy matched controls were examined to determine isometric and isokinetic submaximal shoulder-abduction force steadiness at target forces corresponding to 20%, 27.5%, and 35% of the maximal shoulder abductor torque, and maximal shoulder muscle strength......We investigated the effects of the subacromial impingement syndrome (SIS) on shoulder sensory-motor control and maximal shoulder muscle strength. It was hypothesized that both would be impaired due to chronic shoulder pain associated with the syndrome. Nine subjects with unilateral SIS who remained...... (MVC). Electromyographic (EMG) activity was assessed using surface and intramuscular recordings from eight shoulder muscles. Force steadiness was impaired in SIS subjects during concentric contractions at the highest target force level only, with muscle activity largely unaffected. No between...

  6. Sodium nitrate ingestion increases skeletal muscle nitrate content in humans.

    Science.gov (United States)

    Nyakayiru, Jean; Kouw, Imre W K; Cermak, Naomi M; Senden, Joan M; van Loon, Luc J C; Verdijk, Lex B

    2017-09-01

    Nitrate ([Formula: see text]) ingestion has been shown to have vasoactive and ergogenic effects that have been attributed to increased nitric oxide (NO) production. Recent observations in rodents suggest that skeletal muscle tissue serves as an endogenous [Formula: see text] "reservoir." The present study determined [Formula: see text] contents in human skeletal muscle tissue in a postabsorptive state and following ingestion of a sodium nitrate bolus (NaNO 3 ). Seventeen male, type 2 diabetes patients (age 72 ± 1 yr; body mass index 26.5 ± 0.5 kg/m 2 ; means ± SE) were randomized to ingest a dose of NaNO 3 (NIT; 9.3 mg [Formula: see text]/kg body wt) or placebo (PLA; 8.8 mg NaCl/kg body wt). Blood and muscle biopsy samples were taken before and up to 7 h following [Formula: see text] or placebo ingestion to assess [Formula: see text] [and plasma nitrite ([Formula: see text])] concentrations. Additionally, basal plasma and muscle [Formula: see text] concentrations were assessed in 10 healthy young (CON-Y; age 21 ± 1 yr) and 10 healthy older (CON-O; age 75 ± 1 yr) control subjects. In all groups, baseline [Formula: see text] concentrations were higher in muscle (NIT, 57 ± 7; PLA, 61 ± 7; CON-Y, 80 ± 10; CON-O, 54 ± 6 µmol/l) than in plasma (NIT, 35 ± 3; PLA, 32 ± 3; CON-Y, 38 ± 3; CON-O, 33 ± 3 µmol/l; P ≤ 0.011). Ingestion of NaNO 3 resulted in a sustained increase in plasma [Formula: see text], plasma [Formula: see text], and muscle [Formula: see text] concentrations (up to 185 ± 25 µmol/l) in the NIT group (time effect P nitrate ingestion is usually limited to the changes observed in plasma nitrate and nitrite concentrations. The present investigation assessed the skeletal muscle nitrate content in humans during the postabsorptive state, as well as following dietary nitrate ingestion. We show that basal nitrate content is higher in skeletal muscle tissue than in plasma and that ingestion of a dietary nitrate bolus strongly increases both plasma

  7. Increased muscle glucose uptake after exercise

    DEFF Research Database (Denmark)

    Richter, Erik; Ploug, Thorkil; Galbo, Henrik

    1985-01-01

    It has recently been shown that insulin sensitivity of skeletal muscle glucose uptake and glycogen synthesis is increased after a single exercise session. The present study was designed to determine whether insulin is necessary during exercise for development of these changes found after exercise....... Diabetic rats and controls ran on a treadmill and their isolated hindquarters were subsequently perfused at insulin concentrations of 0, 100, and 20,000 microU/ml. Exercise increased insulin sensitivity of glucose uptake and glycogen synthesis equally in diabetic and control rats, but insulin...... responsiveness of glucose uptake was noted only in controls. Analysis of intracellular glucose-6-phosphate, glucose, glycogen synthesis, and glucose transport suggested that the exercise effect on responsiveness might be due to enhancement of glucose disposal. After electrical stimulation of diabetic...

  8. Treinamento isocinético de curto prazo promove aumento da força muscular em indivíduos jovens Short-term isokinetic training increases muscle strength in young subjects

    Directory of Open Access Journals (Sweden)

    Rafael Cunha

    2011-03-01

    Full Text Available O objetivo foi avaliar os efeitos de treinamento isocinético de curta duração no desempenho muscular em indivíduos jovens. Onze homens sadios participaram de um programa de treinamento isocinético de curta duração, composto por 3 sessões (4 séries; 10 repetições isocinéticas concêntricas a 120º.s-1; 2 minutos de intervalo entre séries. A reprodutibilidade dos dados de 2 sessões foi avaliada pelo coeficiente de correlação intraclasses (CCI e teste de Bland e Altman. As avaliações do treinamento foram aplicadas pré e pós a 2ª e 3ª sessões (1 série; 3 repetições concêntricas de extensão do joelho a 60º.s-1, 120º.s-1 e 180º.s-1. Utilizou-se a ANOVA para medidas repetidas e post-hoc de Tukey para verificar diferenças nos testes. O CCI variou de 0,97 a 0,98 em todas as velocidades. Ocorreu um aumento no pico de torque a 60º.s-1 (P=0,03 e 120º.s-1 (P=0,01 após 2 sessões de treinamento. Sugere-se que duas sessões de exercício isocinético foram suficientes para induzir ganhos de força na velocidade treinada (120º.s-1 e em velocidade de contração mais lenta (60º.s-1, em indivíduos jovens.The aim was to investigate the effects of short-term isokinetic training on muscle performance in young individuals. Eleven healthy males subjects underwent to short-term training, consisting of 3 sessions (4 sets, 10 repetitions of concentric isokinetic exercise at 120º.s-1; 2-minute interval between sets. Data reproducibility from two sessions was evaluated by intraclass correlation coefficient (ICC and Bland and Altman test. Training assessments were made pre and post the 2nd and 3rd sessions (1 set, 3 repetitions of concentric knee extension at 60º.s-1, 120º.s-1 and 180º.s-1. An ANOVA for repeated measures and Tukey post-hoc test was applied to determine differences between tests. The ICC ranged from 0.97 to 0.98 for all velocities. There was an increase in peak torque at 60º.s-1 (P=0,03 and 120º.s-1 (P=0,01 after 2

  9. Neck kinematics and sternocleidomastoid muscle activation during neck rotation in subjects with forward head posture

    Science.gov (United States)

    Kim, Man-Sig

    2015-01-01

    [Purpose] The present study investigated differences in the kinematics of the neck and activation of the sternocleidomastoid (SCM) muscle during neck rotation between subjects with and without forward head posture (FHP). [Subjects and Methods] Twenty-eight subjects participated in the study (14 with FHP, 14 without FHP). Subjects performed neck rotation in two directions, left and right. The kinematics of rotation-lateral flexion movement patterns were recorded using motion analysis. Activity in the bilateral SCM muscles was measured using surface electromyography. Differences in neck kinematics and activation of SCM between the groups were analyzed by independent t-tests. [Results] Maintaining FHP increased the rotation-lateral flexion ratio significantly in both directions. The FHP group had significantly faster onset time for lateral flexion movement in both directions during neck rotation. Regarding the electromyography of the SCM muscles during neck rotation in both directions, the activity values of subjects with FHP were greater than those of subjects without FHP for the contralateral SCM muscles. [Conclusion] FHP can induce changes in movement in the frontal plane and SCM muscle activation during neck rotation. Thus, clinicians should consider movement in the frontal plane as well as in the sagittal plane when assessing and treating patients with forward head posture. PMID:26696712

  10. Concentric resistance training increases muscle strength without affecting microcirculation

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Marc-Andre [Department of Diagnostic and Interventional Radiology, University of Heidelberg, Heidelberg (Germany)], E-mail: MarcAndre.Weber@med.uni-heidelberg.de; Hildebrandt, Wulf [Immunochemistry, German Cancer Research Center (dkfz), Heidelberg (Germany); Schroeder, Leif [Medical Physics in Radiology, German Cancer Research Center (dkfz), Heidelberg (Germany); Kinscherf, Ralf [Department of Anatomy and Developmental Biology, University of Heidelberg, Heidelberg (Germany); Krix, Martin [Radiology, German Cancer Research Center (dkfz), Heidelberg (Germany); Bachert, Peter [Medical Physics in Radiology, German Cancer Research Center (dkfz), Heidelberg (Germany); Delorme, Stefan; Essig, Marco [Radiology, German Cancer Research Center (dkfz), Heidelberg (Germany); Kauczor, Hans-Ulrich [Department of Diagnostic and Interventional Radiology, University of Heidelberg, Heidelberg (Germany); Krakowski-Roosen, Holger [National Center for Tumor Diseases (NCT), Heidelberg (Germany)

    2010-03-15

    Purpose: While the evidence is conclusive regarding the positive effects of endurance training, there is still some controversy regarding the effects of resistance training on muscular capillarity. Thus, the purpose was to assess whether resistance strength training influences resting skeletal muscle microcirculation in vivo. Materials and methods: Thirty-nine middle-aged subjects (15 female, 24 male; mean age, 54 {+-} 9 years) were trained twice a week on an isokinetic system (altogether 16 sessions lasting 50 min, intensity 75% of maximum isokinetic and isometric force of knee flexors and extensors). To evaluate success of training, cross-sectional area (CSA) of the quadriceps femoris muscle and its isokinetic and isometric force were quantified. Muscular capillarization was measured in biopsies of the vastus lateralis muscle. In vivo, muscular energy and lipid metabolites were quantified by magnetic resonance spectroscopy and parameters of muscular microcirculation, such as local blood volume, blood flow and velocity, by contrast-enhanced ultrasound analyzing replenishment kinetics. Results: The significant (P < 0.001) increase in CSA (60 {+-} 16 before vs. 64 {+-} 15 cm{sup 2} after training) and in absolute muscle strength (isometric, 146 {+-} 44 vs. 174 {+-} 50 Nm; isokinetic, 151 {+-} 53 vs. 174 {+-} 62 Nm) demonstrated successful training. Neither capillary density ex vivo (351 {+-} 75 vs. 326 {+-} 62) nor ultrasonographic parameters of resting muscle perfusion were significantly different (blood flow, 1.2 {+-} 1.2 vs. 1.1 {+-} 1.1 ml/min/100 g; blood flow velocity, 0.49 {+-} 0.44 vs. 0.52 {+-} 0.74 mm s{sup -1}). Also, the intensities of high-energy phosphates phosphocreatine and {beta}-adenosintriphosphate were not different after training within the skeletal muscle at rest ({beta}-ATP/phosphocreatine, 0.29 {+-} 0.06 vs. 0.28 {+-} 0.04). Conclusion: The significant increase in muscle size and strength in response to concentric isokinetic and isometric

  11. Force steadiness, muscle activity, and maximal muscle strength in subjects with subacromial impingement syndrome.

    Science.gov (United States)

    Bandholm, Thomas; Rasmussen, Lars; Aagaard, Per; Jensen, Bente Rona; Diederichsen, Louise

    2006-11-01

    We investigated the effects of the subacromial impingement syndrome (SIS) on shoulder sensory-motor control and maximal shoulder muscle strength. It was hypothesized that both would be impaired due to chronic shoulder pain associated with the syndrome. Nine subjects with unilateral SIS who remained physically active in spite of shoulder pain and nine healthy matched controls were examined to determine isometric and isokinetic submaximal shoulder-abduction force steadiness at target forces corresponding to 20%, 27.5%, and 35% of the maximal shoulder abductor torque, and maximal shoulder muscle strength (MVC). Electromyographic (EMG) activity was assessed using surface and intramuscular recordings from eight shoulder muscles. Force steadiness was impaired in SIS subjects during concentric contractions at the highest target force level only, with muscle activity largely unaffected. No between-group differences in shoulder MVC were observed. The present data suggest that shoulder sensory-motor control is only mildly impaired in subjects with SIS who are able to continue with upper body physical activity in spite of shoulder pain. Thus, physical activity should be continued by patients with SIS, if possible, to avoid the loss in neural and muscle functions associated with inactivity.

  12. Nutritional strategies of physically active subjects with muscle dysmorphia.

    Science.gov (United States)

    Contesini, Nadir; Adami, Fernando; Blake, Márcia de-Toledo; Monteiro, Carlos Bm; Abreu, Luiz C; Valenti, Vitor E; Almeida, Fernando S; Luciano, Alexandre P; Cardoso, Marco A; Benedet, Jucemar; de Assis Guedes de Vasconcelos, Francisco; Leone, Claudio; Frainer, Deivis Elton Schlickmann

    2013-05-26

    The aim of this study was to identify dietary strategies for physically active individuals with muscle dysmorphia based on a systematic literature review. References were included if the study population consisted of adults over 18 years old who were physically active in fitness centers. We identified reports through an electronic search ofScielo, Lilacs and Medline using the following keywords: muscle dysmorphia, vigorexia, distorted body image, and exercise. We found eight articles in Scielo, 17 in Medline and 12 in Lilacs. Among the total number of 37 articles, only 17 were eligible for inclusion in this review. The results indicated that the feeding strategies used by physically active individuals with muscle dysmorphia did not include planning or the supervision of a nutritionist. Diet included high protein and low fat foods and the ingestion of dietary and ergogenic supplements to reduce weight. Physically active subjects with muscle dysmorphia could benefit from the help of nutritional professionals to evaluate energy estimation, guide the diet and its distribution in macronutrient and consider the principle of nutrition to functional recovery of the digestive process, promote liver detoxification, balance and guide to organic adequate intake of supplemental nutrients and other substances.

  13. Increased muscle interstitial levels of inflammatory cytokines in polymyalgia rheumatica

    DEFF Research Database (Denmark)

    Kreiner, Frederik; Langberg, Henning; Galbo, Henrik

    2010-01-01

    Polymyalgia rheumatica (PMR) is characterized by aching of the proximal muscles and increased blood levels of markers of inflammation. Despite the muscle complaints, the current view is that symptoms are caused by inflammation in synovial structures. The purpose of this study was to elucidate the...... the disease mechanisms in symptomatic muscles by measuring interstitial levels of cytokines before and after prednisolone treatment....

  14. RAPID KNEE-EXTENSIONS TO INCREASE QUADRICEPS MUSCLE ACTIVITY IN PATIENTS WITH TOTAL KNEE ARTHROPLASTY

    DEFF Research Database (Denmark)

    Husted, Rasmus Skov; Wilquin, Lousia; Jakobsen, Thomas Linding

    2017-01-01

    BACKGROUND: Inhibition of the quadriceps muscle and reduced knee-extension strength is common shortly following total knee arthroplasty (weeks to months), due to reduced voluntary activation of the quadriceps muscle. In healthy subjects, strength training with heavy loads is known to increase ago...

  15. Rapid knee-extensions to increase quadriceps muscle activity in patients with total knee arthroplasty

    DEFF Research Database (Denmark)

    Husted, Rasmus Skov; Wilquin, Lousia; Jakobsen, Thomas Linding

    2017-01-01

    BACKGROUND: Inhibition of the quadriceps muscle and reduced knee-extension strength is common shortly following total knee arthroplasty (weeks to months), due to reduced voluntary activation of the quadriceps muscle. In healthy subjects, strength training with heavy loads is known to increase ago...

  16. Increased blood pressure can reduce fatigue of thenar muscles paralyzed after spinal cord injury

    NARCIS (Netherlands)

    Butler, JE; Ribot-Ciscar, E; Zijdewind, Inge; Thomas, CK

    The aim of this study was to evaluate whether increases in blood pressure, and presumably muscle perfusion pressure, improve the endurance of thenar muscles paralyzed chronically by cervical spinal cord injury (SCI). Resting mean arterial pressure (MAP) was low in all eight subjects (64 +/- 2 mmHg).

  17. THE NEPHROTOXICITY RISK IN RATS SUBJECTED TO HEAVY MUSCLE ACTIVITY

    Directory of Open Access Journals (Sweden)

    Gülsen Öner

    2009-09-01

    Full Text Available When the body is exposed to insults, the kidneys exhibit adaptive changes termed renal cytoresistance, characterized by cholesterol accumulation in the membranes of the tubule cells. However, heavy muscle activity has not yet been accepted as one of the stressors that could lead to cytoresistance. In order to study the renal functional characteristics of animals exposed to heavy muscle activity, rats were subjected to exhaustive treadmill exercise for 5 days and their data was compared to those of sedentary controls. It was found that in exercised rats, blood lactate, muscle citrate synthase and proximal tubule peroxynitrite levels were all elevated, suggesting the presence of oxidative stress in the proximal tubule segments. However, mean arterial pressure, renal blood flow, glomerular filtration rate, fractional excretion of sodium and potassium, and organic anion excretion remained normal. Despite unchanged blood cholesterol levels, cholesterol loading in the proximal tubule segments, especially the free form, and decreased lactate dehydrogenase release from cytoresistant proximal tubule segments indicated the development of renal cytoresistance. However, this resistance did not seem to have protected the kidneys as expected because organic anion accumulation associated with glycosuria and proteinuria, in addition to the elevated urinary cholesterol levels, all imply the presence of an impaired glomerular permeability and reabsorption in the proximal tubule cells. Therefore, we suggest that in response to heavy muscle activity the tubular secretion may remain intact, although cytoresistance in the proximal tubule cells may affect the tubular reabsorptive functions and basolateral uptake of substances. Thus, this differential sensitivity in the cytoresistance should be taken into account during functional evaluation of the kidneys

  18. Strength, endurance, and work capacity after muscle strengthening exercise in postpolio subjects.

    Science.gov (United States)

    Agre, J C; Rodriquez, A A; Franke, T M

    1997-07-01

    To determine whether a 12-week home quadriceps muscle strengthening exercise program would increase muscle strength, isometric endurance, and tension time index (TTI) in postpolio syndrome subjects without adversely affecting the surviving motor units or the muscle. A longitudinal study to investigate the effect of a 12-week exercise program on neuromuscular function and electromyographic variables. Neuromuscular laboratory of a university hospital. Seven subjects were recruited from a cohort of 12 subjects who had participated in a previous exercise study. All subjects had greater than antigravity strength of the quadriceps. Upon completion of a postpolio questionnaire, all acknowledged common postpolio syndrome symptoms such as new fatigue, pain, and weakness; 6 of the 7 acknowledged new strength decline. On Mondays and Thursdays subjects performed three sets of four maximal isometric contractions of the quadriceps held for 5 seconds each. On Tuesdays and Fridays subjects performed three sets of 12 dynamic knee extension exercises with ankle weights. Neuromuscular variables of the quadriceps muscles were measured at the beginning and completion of the exercise program and included: isokinetic peak torque (ISOKPT, at 60 degrees/sec angular velocity) and total work performed of four contractions (ISOKTW), isometric peak torque (MVC), endurance (EDUR, time subject could hold isometric contraction at 40% of the initial MVC), isometric tension time index (TTI, product of endurance time and torque at 40% of MVC), and initial and final ankle weight (WGT, kg) lifted. Electromyographic variables included: fiber density (FD), jitter (MCD), and blocking (BLK) from single fiber assessment and median macro amplitude (MACRO). Serum creatine kinase (CK) was also measured initially and at 4-week intervals throughout the study. The following variables significantly (p .05) change: FD, MCD, BLK, MACRO, and CK. This home exercise program significantly increased strength, endurance

  19. Simultaneous Knee Extensor Muscle Action Induces an Increase in Voluntary Force Generation of Plantar Flexor Muscles.

    Science.gov (United States)

    Suzuki, Takahito; Shioda, Kohei; Kinugasa, Ryuta; Fukashiro, Senshi

    2017-02-01

    Suzuki, T, Shioda, K, Kinugasa, R, and Fukashiro, S. Simultaneous knee extensor muscle action induces an increase in voluntary force generation of plantar flexor muscles. J Strength Cond Res 31(2): 365-371, 2017-Maximum activation of the plantar flexor muscles is required for various sporting activities that involve simultaneous plantar flexion and knee extension. During a multi-joint movement, activation of the plantar flexor muscles is affected by the activity of the knee extensor muscles. We hypothesized that coactivation of the plantar flexor muscles and knee extensor muscles would result in a higher plantar flexion torque. To test this hypothesis, 8 male volunteers performed maximum voluntary isometric action of the plantar flexor muscles with and without isometric action of the knee extensor muscles. Surface electromyographic data were collected from 8 muscles of the right lower limb. Voluntary activation of the triceps surae muscles, evaluated using the interpolated twitch technique, significantly increased by 6.4 percentage points with intentional knee extensor action (p = 0.0491). This finding is in line with a significant increase in the average rectified value of the electromyographic activity of the vastus lateralis, fibularis longus, and soleus muscles (p = 0.013, 0.010, and 0.045, respectively). The resultant plantar flexion torque also significantly increased by 11.5% of the predetermined maximum (p = 0.031). These results suggest that higher plantar flexor activation coupled with knee extensor activation facilitates force generation during a multi-joint task.

  20. Single muscle fibre contractile properties differ between body-builders, power athletes and control subjects.

    Science.gov (United States)

    Meijer, J P; Jaspers, R T; Rittweger, J; Seynnes, O R; Kamandulis, S; Brazaitis, M; Skurvydas, A; Pišot, R; Šimunič, B; Narici, M V; Degens, H

    2015-11-01

    What is the central question of this study? Do the contractile properties of single muscle fibres differ between body-builders, power athletes and control subjects? What is the main finding and its importance? Peak power normalized for muscle fibre volume in power athletes is higher than in control subjects. Compared with control subjects, maximal isometric tension (normalized for muscle fibre cross-sectional area) is lower in body-builders. Although this difference may be caused in part by an apparent negative effect of hypertrophy, these results indicate that the training history of power athletes may increase muscle fibre quality, whereas body-building may be detrimental. We compared muscle fibre contractile properties of biopsies taken from the vastus lateralis of 12 body-builders (BBs; low- to moderate-intensity high-volume resistance training), six power athletes (PAs; high-intensity, low-volume combined with aerobic training) and 14 control subjects (Cs). Maximal isotonic contractions were performed in single muscle fibres, typed with SDS-PAGE. Fibre cross-sectional area was 67 and 88% (P power (PP) of PA fibres was 58% higher than that of BB fibres (P < 0.05), whereas BB fibres, despite considerable hypertrophy, had similar PP to the C fibres. This work suggests that high-intensity, low-volume resistance training with aerobic exercise improves PP, while low- to moderate-intensity high-volume resistance training does not affect PP and results in a reduction in specific tension. We postulate that the decrease in specific tension is caused by differences in myofibrillar density and/or post-translational modifications of contractile proteins. © 2015 The Authors. Experimental Physiology © 2015 The Physiological Society.

  1. Increased bilateral interactions in middle-aged subjects

    Directory of Open Access Journals (Sweden)

    Jolien eHeetkamp

    2014-01-01

    Full Text Available A hallmark of the age-related neural reorganization is that old vs. young adults execute typical motor tasks by a more diffuse neural activation pattern including stronger ipsilateral activation during unilateral tasks. Whether such changes in neural activation are present already at middle age and affect bimanual interactions is unknown. We compared the amount of associated activity, i.e., muscle activity and force produced by the non-task hand and motor evoked potentials (MEPs produced by magnetic brain stimulation between young (mean 24 y, n = 10 and middle-aged (mean 50 y, n = 10 subjects during brief unilateral (7 levels of % maximal voluntary contractions, MVC and bilateral contractions (4 x 7 levels of % MVC combinations, and during a 120-s-long MVC of sustained unilateral index finger abduction. During the force production the excitability of the ipsilateral (iM1 or contralateral (cM1 primary motor cortex was assessed. The associated activity in the ‘resting’ hand was ~2-fold higher in middle-aged (28% of MVC vs. young adults (11% of MVC during brief unilateral MVCs. After controlling for background muscle activity, MEPs in iM1 were similar in the two groups during brief unilateral contractions. At low (bilateral forces only, MEPs evoked in cM1 were 30% higher in the middle-aged vs. young adults. At the start of the sustained contraction, the associated activity was higher in the middle-aged vs. young subjects and increased progressively in both groups (30% vs. 15% MVC at 120 s, respectively. MEPs were greater at the start of the sustained contraction in middle-aged subjects but increased further during the contraction only in young adults. Under these experimental conditions, the data provide evidence for the reorganization of neural control of unilateral force production as early as age 50. Future studies will determine if the altered neural control of such inter-manual interactions are of functional significance.

  2. Increased skeletal muscle capillarization enhances insulin sensitivity

    DEFF Research Database (Denmark)

    Åkerström, Thorbjörn; Laub, Lasse; Vedel, Kenneth

    2014-01-01

    . Skeletal muscle specific angiogenesis was induced by adding the α1-adrenergic receptor antagonist Prazosin to the drinking water of Sprague Dawley rats (n=33) while 34 rats served as controls. Insulin sensitivity was measured ≥40 h after termination of the 3-week Prazosin treatment, which ensured...... that Prazosin was cleared from the blood stream. Whole-body insulin sensitivity was measured in conscious, unrestrained rats by hyperinsulinemic euglycemic clamp. Tissue specific insulin sensitivity was assessed by administration of 2-deoxy-[(3)H]-Glucose during the plateau phase of the clamp. Whole-body...

  3. Respiratory muscle training increases respiratory muscle strength and reduces respiratory complications after stroke: a systematic review

    Directory of Open Access Journals (Sweden)

    Kênia KP Menezes

    2016-07-01

    Full Text Available Question: After stroke, does respiratory muscle training increase respiratory muscle strength and/or endurance? Are any benefits carried over to activity and/or participation? Does it reduce respiratory complications? Design: Systematic review of randomised or quasi-randomised trials. Participants: Adults with respiratory muscle weakness following stroke. Intervention: Respiratory muscle training aimed at increasing inspiratory and/or expiratory muscle strength. Outcome measures: Five outcomes were of interest: respiratory muscle strength, respiratory muscle endurance, activity, participation and respiratory complications. Results: Five trials involving 263 participants were included. The mean PEDro score was 6.4 (range 3 to 8, showing moderate methodological quality. Random-effects meta-analyses showed that respiratory muscle training increased maximal inspiratory pressure by 7 cmH2O (95% CI 1 to 14 and maximal expiratory pressure by 13 cmH2O (95% CI 1 to 25; it also decreased the risk of respiratory complications (RR 0.38, 95% CI 0.15 to 0.96 compared with no/sham respiratory intervention. Whether these effects carry over to activity and participation remains uncertain. Conclusion: This systematic review provided evidence that respiratory muscle training is effective after stroke. Meta-analyses based on five trials indicated that 30 minutes of respiratory muscle training, five times per week, for 5 weeks can be expected to increase respiratory muscle strength in very weak individuals after stroke. In addition, respiratory muscle training is expected to reduce the risk of respiratory complications after stroke. Further studies are warranted to investigate whether the benefits are carried over to activity and participation. Registration: PROSPERO (CRD42015020683. [Menezes KKP, Nascimento LR, Ada L, Polese JC, Avelino PR, Teixeira-Salmela LF (2016 Respiratory muscle training increases respiratory muscle strength and reduces respiratory

  4. Lumbar and abdominal muscle activity during walking in subjects with chronic low back pain: support of the "guarding" hypothesis?

    Science.gov (United States)

    van der Hulst, Marije; Vollenbroek-Hutten, Miriam M; Rietman, Johan S; Hermens, Hermanus J

    2010-02-01

    It has been hypothesized that changes in trunk muscle activity in chronic low back pain (CLBP) reflect an underlying "guarding" mechanism, which will manifest itself as increased superficial abdominal - and lumbar muscle activity. During a functional task like walking, it may be further provoked at higher walking velocities. The purpose of this cross sectional study was to investigate whether subjects with CLBP show increased co-activation of superficial abdominal - and lumbar muscles during walking on a treadmill, when compared to asymptomatic controls. Sixty-three subjects with CLBP and 33 asymptomatic controls walked on a treadmill at different velocities. Surface electromyography data of the erector spinae, rectus abdominis and obliquus abdominis externus muscles were obtained and averaged per stride. Results show that, compared to asymptomatic controls, subjects with CLBP have increased muscle activity of the erector spinae and rectus abdominis, but not of the obliquus abdominis externus. These differences in trunk muscle activity between groups do not increase with higher walking velocities. In conclusion, the observed increased trunk muscle activity in subjects with CLBP during walking supports the guarding hypothesis.

  5. Latent myofascial trigger points are associated with an increased intramuscular electromyographic activity during synergistic muscle activation.

    Science.gov (United States)

    Ge, Hong-You; Monterde, Sonia; Graven-Nielsen, Thomas; Arendt-Nielsen, Lars

    2014-02-01

    The aim of this study was to evaluate intramuscular muscle activity from a latent myofascial trigger point (MTP) in a synergistic muscle during isometric muscle contraction. Intramuscular activity was recorded with an intramuscular electromyographic (EMG) needle inserted into a latent MTP or a non-MTP in the upper trapezius at rest and during isometric shoulder abduction at 90° performed at 25% of maximum voluntary contraction in 15 healthy subjects. Surface EMG activities were recorded from the middle deltoid muscle and the upper, middle, and lower parts of the trapezius muscle. Maximal pain intensity and referred pain induced by EMG needle insertion and maximal pain intensity during contraction were recorded on a visual analog scale. The results showed that higher visual analog scale scores were observed following needle insertion and during muscle contraction for latent MTPs than non-MTPs (P activity in the upper trapezius muscle was significantly higher at rest and during shoulder abduction at latent MTPs compared with non-MTPs (P latent MTPs are associated with increased intramuscular, but not surface, EMG amplitude of synergist activation. The increased amplitude of synergistic muscle activation may result in incoherent muscle activation pattern of synergists inducing spatial development of new MTPs and the progress to active MTPs. This article presents evidence of increased intramuscular, but not surface, muscle activity of latent MTPs during synergistic muscle activation. This incoherent muscle activation pattern may overload muscle fibers in synergists during muscle contraction and may contribute to spatial pain propagation. Copyright © 2014 American Pain Society. Published by Elsevier Inc. All rights reserved.

  6. Upper Extremity Kinematics and Muscle Activation Patterns in Subjects With Facioscapulohumeral Dystrophy

    NARCIS (Netherlands)

    Bergsma, Arjen; Murgia, Alessio; Cup, Edith H.; Verstegen, Paul P.; Meijer, Kenneth; de Groot, Imelda J.

    Objective: To compare the kinematics and muscle activity of subjects with facioscapulohumeral dystrophy (FSHD) and healthy control subjects during the performance of standardized upper extremity tasks. Design: Exploratory case-control study. Setting: A movement laboratory. Participants: Subjects

  7. Increased collagen synthesis rate during wound healing in muscle.

    Directory of Open Access Journals (Sweden)

    Shaobo Zhou

    Full Text Available Wound healing in muscle involves the deposition of collagen, but it is not known whether this is achieved by changes in the synthesis or the degradation of collagen. We have used a reliable flooding dose method to measure collagen synthesis rate in vivo in rat abdominal muscle following a surgical incision. Collagen synthesis rate was increased by 480% and 860% on days 2 and 7 respectively after surgery in the wounded muscle compared with an undamaged area of the same muscle. Collagen content was increased by approximately 100% at both day 2 and day 7. These results demonstrate that collagen deposition during wound healing in muscle is achieved entirely by an increase in the rate of collagen synthesis.

  8. Fast increase of motor cortical inhibition following postural changes in healthy subjects.

    Science.gov (United States)

    Oliveri, Massimiliano; Caltagirone, Carlo; Loriga, Rita; Pompa, Maria Novella; Versace, Viviana; Souchard, Philippe

    2012-11-14

    Postural reactions are associated with changes in the excitability of the motor system. In the present study we investigated the presence of neurophysiological changes of motor cortical areas targeting muscles of the inferior limbs following treatment with a physiotherapy technique aimed to treat postural dysfunctions by stretching postural muscles, global postural reeducation (GPR). Twenty healthy subjects were evaluated with paired-transcranial magnetic stimulation (TMS) of the motor cortex and recording of motor evoked potentials (MEPs) from peripheral muscles of the inferior limb before and after two GPR manoeuvres applied in different experiments (1 and 2). The effects of GPR were posture- and task-specific: indeed, a GPR manoeuvre applied in standing subjects increased inhibition in cortical areas controlling flexor muscles (Biceps Femoris: ppostural changes on motor cortical disorders. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  9. Metformin increases insulin-stimulated glucose transport in insulin-resistant human skeletal muscle.

    Science.gov (United States)

    Galuska, D; Zierath, J; Thörne, A; Sonnenfeld, T; Wallberg-Henriksson, H

    1991-05-01

    The effect of metformin (0.1 mM) on glucose transport was investigated in healthy control and in insulin-resistant human skeletal muscle. Muscle samples (200-400 mg) were obtained from the rectus abdominis muscle (abdominal surgery) or from the vastus lateralis portion of the quadriceps femoris muscle (open biopsy technique) from 8 healthy controls (age 38 +/- 4 yrs, BMI 23 +/- 1) and from 6 insulin-resistant subjects (age 53 +/- 5 yrs, BMI 30 +/- 2). Metformin had no effect on basal or insulin-stimulated (100 microU/ml) 3-0-methylglucose transport in incubated muscle strips from healthy subjects. Muscle tissue from the insulin resistant group did not respond to 100 microU/ml of insulin (0.73 +/- 0.17 for basal and 0.81 +/- 0.22 mumol x ml-1 x h-1 for insulin-stimulation, NS). Basal glucose transport was unaffected by metformin, whereas insulin-stimulated (100 microU/ml) glucose transport was increased by 63% in the insulin-resistant muscles (0.73 +/- 0.17 in the absence vs 1.19 +/- 0.18 mumol x ml-1 x h-1 in the presence of metformin, p less than 0.05). In conclusion, metformin abolishes insulin-resistance in human skeletal muscle by normalizing insulin-stimulated glucose transport accross the muscle cell membrane. The mechanism for this effect remains to be elucidated.

  10. Muscle fiber size increases following resistance training in multiple sclerosis

    DEFF Research Database (Denmark)

    Dalgas, U; Stenager, E; Jakobsen, Johannes Klitgaard

    2010-01-01

    To test the hypothesis that lower body progressive resistance training (PRT) leads to an increase of the muscle fiber cross-sectional area (CSA) and a shift in the proportion of fiber types in patients with multiple sclerosis (MS).......To test the hypothesis that lower body progressive resistance training (PRT) leads to an increase of the muscle fiber cross-sectional area (CSA) and a shift in the proportion of fiber types in patients with multiple sclerosis (MS)....

  11. Inspiratory muscle activation increases with COPD severity as confirmed by non-invasive mechanomyographic analysis.

    Directory of Open Access Journals (Sweden)

    Leonardo Sarlabous

    Full Text Available There is a lack of instruments for assessing respiratory muscle activation during the breathing cycle in clinical conditions. The aim of the present study was to evaluate the usefulness of the respiratory muscle mechanomyogram (MMG for non-invasively assessing the mechanical activation of the inspiratory muscles of the lower chest wall in both patients with chronic obstructive pulmonary disease (COPD and healthy subjects, and to investigate the relationship between inspiratory muscle activation and pulmonary function parameters. Both inspiratory mouth pressure and respiratory muscle MMG were simultaneously recorded under two different respiratory conditions, quiet breathing and incremental ventilatory effort, in 13 COPD patients and 7 healthy subjects. The mechanical activation of the inspiratory muscles was characterised by the non-linear multistate Lempel-Ziv index (MLZ calculated over the inspiratory time of the MMG signal. Subsequently, the efficiency of the inspiratory muscle mechanical activation was expressed as the ratio between the peak inspiratory mouth pressure to the amplitude of the mechanical activation. This activation estimated using the MLZ index correlated strongly with peak inspiratory mouth pressure throughout the respiratory protocol in both COPD patients (r = 0.80, p<0.001 and healthy (r = 0.82, p<0.001. Moreover, the greater the COPD severity in patients, the greater the level of muscle activation (r = -0.68, p = 0.001, between muscle activation at incremental ventilator effort and FEV1. Furthermore, the efficiency of the mechanical activation of inspiratory muscle was lower in COPD patients than healthy subjects (7.61±2.06 vs 20.42±10.81, respectively, p = 0.0002, and decreased with increasing COPD severity (r = 0.78, p<0.001, between efficiency of the mechanical activation at incremental ventilatory effort and FEV1. These results suggest that the respiratory muscle mechanomyogram is a good reflection of inspiratory

  12. Sulfonylurea therapy improves glucose disposal without changing skeletal muscle GLUT4 levels in noninsulin-dependent diabetes mellitus subjects

    DEFF Research Database (Denmark)

    Vestergaard, H; Weinreb, J E; Rosen, A S

    1995-01-01

    A major pathological feature of noninsulin-dependent diabetes (NIDDM) is defective insulin-stimulated glucose transport in skeletal muscle. When NIDDM subjects are assessed as a group, GLUT4 gene expression in skeletal muscle varies widely and is not different from that in controls. Thus, longitu......A major pathological feature of noninsulin-dependent diabetes (NIDDM) is defective insulin-stimulated glucose transport in skeletal muscle. When NIDDM subjects are assessed as a group, GLUT4 gene expression in skeletal muscle varies widely and is not different from that in controls. Thus......, longitudinal studies are needed to assess whether changes in GLUT4 expression in muscle of NIDDM subjects could be responsible for changes in glucose disposal. The question is timely because recent studies in transgenic mice show that increasing GLUT4 expression can increase insulin-stimulated glucose uptake...... in vivo and in vitro. Here we use a longitudinal design to investigate the effects of 8 weeks of therapy with the sulfonylurea gliclazide on glycemic control, glucose tolerance, insulin-stimulated glucose disposal, and GLUT4 expression in muscle of 10 obese NIDDM subjects. Subjects were on a weight...

  13. Increasing muscle extensibility: a matter of increasing length or modifying sensation?

    DEFF Research Database (Denmark)

    Weppler, Cynthia Holzman; Magnusson, S Peter; Weppler, Cynthia Holzman

    2010-01-01

    Various theories have been proposed to explain increases in muscle extensibility observed after intermittent stretching. Most of these theories advocate a mechanical increase in length of the stretched muscle. More recently, a sensory theory has been proposed suggesting instead that increases in ...

  14. The activity pattern of shoulder muscles in subjects with and without subacromial impingement

    DEFF Research Database (Denmark)

    Diederichsen, Louise Pyndt; Nørregaard, Jesper; Dyhre-Poulsen, Poul

    2009-01-01

    Altered shoulder muscle activity is frequently believed to be a pathogenetic factor of subacromial impingement (SI) and therapeutic interventions have been directed towards restoring normal motor patterns. Still, there is a lack of scientific evidence regarding the changes in muscle activity...... in patients with SI. The aim of the study was to determine and compare the activity pattern of the shoulder muscles in subjects with and without SI. Twenty-one subjects with SI and 20 healthy controls were included. Electromyography (EMG) was assessed from eight shoulder muscles from both shoulders during...... and serratus anterior muscles on the symptomatic side compared to the healthy subjects. On the asymptomatic side, the groups showed different muscle activity during external rotation. Our findings of an altered shoulder muscle activity pattern on both the symptomatic and asymptomatic side in patients indicate...

  15. Increase in corticospinal excitability of limb and trunk muscles according to maintenance of neck flexion.

    Science.gov (United States)

    Fujiwara, Katsuo; Tomita, Hidehito; Kunita, Kenji

    2009-09-25

    The effect of maintenance of neck flexion on corticospinal excitability of limb and trunk muscles was investigated using transcranial magnetic stimulation (TMS). Nine healthy young subjects participated in this experiment. Every measurement was performed with subjects sitting on a chair. Target muscles were the first dorsal interosseous (FDI), biceps brachii (BB), triceps brachii (TB), rectus abdominis (RA), erector spinae (ES), rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and gastrocnemius (GcM) on the right side. TMS was applied to the left primary motor cortex, and motor evoked potential (MEP) was measured from the muscles listed above. Optimal stimulus location and resting motor threshold (RMT) were identified for each target muscle, and stimulus intensity used was 120% of RMT. MEPs of the target muscle were recorded with the chin resting on a chin support (chin-on condition) with neck in 20 degrees of flexion, and with voluntary maintenance of the neck flexion posture (chin-off condition). Amplitude and latency of MEP and background activity of target muscles were analyzed. For FDI, BB, TB, ES, and RF, amplitude of MEP increased and latency shortened in the chin-off compared with the chin-on condition. No significant difference in background activity of each target muscle was found between the two conditions. Corticospinal excitability of limb and trunk muscles was selectively enhanced while neck flexion was maintained.

  16. Activation of human plantar flexor muscles increases after electromyostimulation training.

    Science.gov (United States)

    Maffiuletti, Nicola A; Pensini, Manuela; Martin, Alain

    2002-04-01

    Neuromuscular adaptations of the plantar flexor muscles were assessed before and subsequent to short-term electromyostimulation (EMS) training. Eight subjects underwent 16 sessions of isometric EMS training over 4 wk. Surface electromyographic (EMG) activity and torque obtained under maximal voluntary and electrically evoked contractions were analyzed to distinguish neural adaptations from contractile changes. After training, plantar flexor voluntary torque significantly increased under isometric conditions at the training angle (+8.1%, P < 0.05) and at the two eccentric velocities considered (+10.8 and +13.1%, P < 0.05). Torque gains were accompanied by higher normalized soleus EMG activity and, in the case of eccentric contractions, also by higher gastrocnemii EMG (P < 0.05). There was an 11.9% significant increase in both plantar flexor maximal voluntary activation (P < 0.01) and postactivation potentiation (P < 0.05), whereas contractile properties did not change after training. In the absence of a change in the control group, it was concluded that an increase in neural activation likely mediates the voluntary torque gains observed after short-term EMS training.

  17. Four-week exercise program does not change rotator cuff muscle activation and scapular kinematics in healthy subjects.

    Science.gov (United States)

    Lin, Yin-Liang; Karduna, Andrew

    2016-12-01

    Rotator cuff and scapular muscle strengthening exercises are an essential part of shoulder rehabilitation and sports training. Although the effect of exercise training on pain and function have been widely investigated, few studies have focused on the changes in shoulder kinematics and muscle activity after exercise training. Therefore, the purpose of the present study was to investigate the effect of rotator cuff and scapular strengthening exercises on shoulder kinematics and the activation of rotator cuff and scapular muscles in healthy subjects. Thirty-six healthy subjects were recruited and randomly assigned into either a training or control group. Subjects in the training group were trained with rotator cuff and scapular strengthening exercises for 4 weeks. Scapular kinematics and shoulder muscle activity during arm elevation were measured before and after exercise training. After the 4-week training protocol, there was an increase in strength and a decrease in upper trapezius activation in the training group, which is consistent with previous studies. However, no difference was found in scapular kinematics and activation of rotator cuff muscles between the control and training groups after the training protocol. Although the exercise protocol resulted in strength gains for the rotator cuff, these gains did not transfer to an increase in muscle activation during motion. These results demonstrate the difficulty in changing activation patterns of the rotator cuff muscles. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2079-2088, 2016. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  18. Latent myofascial trigger points are associated with an increased antagonistic muscle activity during agonist muscle contraction.

    Science.gov (United States)

    Ibarra, José Miota; Ge, Hong-You; Wang, Chao; Martínez Vizcaíno, Vicente; Graven-Nielsen, Thomas; Arendt-Nielsen, Lars

    2011-12-01

    The aim of this study was to evaluate motor unit activity from a latent myofascial trigger point (MTP) in an antagonist muscle during isometric agonist muscle contraction. Intramuscular activity was recorded with an intramuscular electromyographic (EMG) needle inserted into a latent MTP or a non-MTP in the posterior deltoid muscle at rest and during isometric shoulder flexion performed at 25% of maximum voluntary contraction in 14 healthy subjects. Surface EMGs were recorded from the anterior and posterior deltoid muscles. Maximal pain intensity and referred pain induced by EMG needle insertion were recorded on a visual analogue scale. The results showed that higher local pain was observed following needle insertion into latent MTPs (4.64 ± .48 cm) than non-MTPs (2.35 ± .43 cm, P muscle was significantly higher at rest and during shoulder flexion at latent MTPs than non-MTPs (P muscle relaxation following exercise, disordered fine movement control, and unbalanced muscle activation. Elimination of latent MTPs and/or prevention of latent MTPs from becoming active may improve motor functions. Copyright © 2011 American Pain Society. Published by Elsevier Inc. All rights reserved.

  19. Comparison of Antagonist Muscle Activity During Walking Between Total Knee Replacement and Control Subjects Using Unnormalized Electromyography.

    Science.gov (United States)

    Lundberg, Hannah J; Rojas, Idubijes L; Foucher, Kharma C; Wimmer, Markus A

    2016-06-01

    Although satisfactory outcomes have been reported after total knee replacement (TKR), full recovery of muscle strength and physical function is rare. We developed a relative activation index (RAI) to compare leg muscle activity from unnormalized surface electromyography (sEMG) between TKR and control subjects. Nineteen TKR and 19 control subjects underwent gait analysis and sEMG. RAIs were calculated by dividing the average sEMG for 2 consecutive subphases of stance defined by the direction of the external sagittal plane moment (flexion or extension). RAIs and external moments indicate TKR subjects have less initial stance antagonist rectus femoris activity (P = .004), greater middle stance antagonist biceps femoris activity (P < .001), and less late stance agonist biceps femoris activity (P < .001) than control subjects. Individuals with TKR demonstrate increased flexor muscle activation during weight bearing, potentially contributing to altered gait patterns found during the stance phase of gait. The RAI helps detail whether decreased external moments correspond to less agonist or more antagonist muscle activity to determine true muscle activity differences between subject groups. Identifying the mechanisms underlying altered muscle function both before and after TKR is critical for developing rehabilitation strategies to address functional deficits and disability found in this patient population. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Whole-body-vibration-induced increase in leg muscle activity during different squat exercises.

    Science.gov (United States)

    Roelants, Machteld; Verschueren, Sabine M P; Delecluse, Christophe; Levin, Oron; Stijnen, Valère

    2006-02-01

    This study analyzed leg muscle activity during whole-body vibration (WBV) training. Subjects performed standard unloaded isometric exercises on a vibrating platform (Power Plate): high squat (HS), low squat (LS), and 1-legged squat (OL). Muscle activity of the rectus femoris, vastus lateralis, vastus medialis, and gastrocnemius was recorded in 15 men (age 21.2 +/- 0.8 years) through use of surface electromyography (EMG). The exercises were performed in 2 conditions: with WBV and without (control [CO]) a vibratory stimulus of 35 Hz. Muscle activation during WBV was compared with CO and with muscle activation during isolated maximal voluntary contractions (MVCs). Whole-body vibration resulted in a significantly higher (p < 0.05) EMG root-mean-square compared with CO in all muscle groups and all exercises (between +39.9 +/- 17.5% and +360.6 +/- 57.5%). The increase in muscle activity caused by WBV was significantly higher (p < 0.05) in OL compared with HS and LS. In conclusion, WBV resulted in an increased activation of the leg muscles. During WBV, leg muscle activity varied between 12.6 and 82.4% of MVC values.

  1. A novel noninvasive method for measuring fatigability of the quadriceps muscle in noncooperating healthy subjects

    DEFF Research Database (Denmark)

    Poulsen, Jesper Brøndum; Rose, Martin Høyer; Møller, Kirsten

    2015-01-01

    days, nonvoluntary isometric contractions (twitch and tetanic) of the quadriceps femoris muscle evoked by transcutaneous electrical muscle stimulation were recorded in twelve healthy adults. For tetanic contractions, the Fatigue Index (ratio of peak torque values) and the slope of the regression line......Background. Critical illness is associated with muscle weakness leading to long-term functional limitations. Objectives. To assess the reliability of a novel method for evaluating fatigability of the quadriceps muscle in noncooperating healthy subjects. Methods. On two occasions, separated by seven...... fatigability of the quadriceps muscle produces reliable results in healthy subjects and may provide valuable data on quantitative changes in muscle working capacity and treatment effects in patients who are incapable of producing voluntary muscle contractions....

  2. Infield masticatory muscle activity in subjects with pain-related temporomandibular disorders diagnoses.

    Science.gov (United States)

    Khawaja, S N; McCall, W; Dunford, R; Nickel, J C; Iwasaki, L R; Crow, H C; Gonzalez, Y

    2015-04-01

    Pain-related temporomandibular disorders (TMDs) are the most prevalent conditions among TMDs. There is contrasting evidence available for association of pain-related TMD and masticatory muscle activity (MMA). The present investigation assesses the associations between MMA levels of masseter and temporalis muscles during awake and sleep among pain-related TMD diagnostic groups. The department of Oral Diagnostic Sciences, University at Buffalo. Twenty females and six males participated in this study. Using the diagnostic criteria for temporomandibular disorders (DC-TMDs), participants were diagnostically categorized. Subjects used a custom monitoring system, which recorded infield muscle activities. A factorial model tested for association between independent variable (muscle, time period, MMA level, and diagnostic group) effects and the logarithm of MMA. Greenhouse-Geisser test was used to determine any statistically significant associations (p≤0.003). No statistically significant association was found between four-way, three-way, and two-way analyses. However, among the main effects, range of magnitudes was the only variable to be statistically significant. Although the data suggest a trend of increased masseter MMA in the pain-related TMD diagnoses group both during awake and sleep time periods, such observation is not maintained for the temporalis muscle. In addition, temporalis MMA was found to be higher in the pain-related TMD diagnoses group only at extreme activity levels (<25 and ≥80% ranges). This data support the association between masticatory muscle hyperactivity and painful TMD conditions. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. In-field masticatory muscle activity in subjects with pain-related TMD diagnoses

    Science.gov (United States)

    Khawaja, S.N.; McCall, W.; Dunford, R.; Nickel, J.C.; Iwasaki, L.R.; Crow, H.C.; Gonzalez, Y.

    2015-01-01

    Objectives Pain-related Temporomandibular disorders (TMD) are the most prevalent conditions among TMDs. There is contrasting evidence available for association of pain-related TMD and masticatory muscle activity (MMA). The present investigation assesses the associations between MMA levels of masseter and temporalis muscles during awake and sleep among pain-related TMD diagnostic groups. Setting and Sample Population The department of Oral Diagnostic Sciences, University at Buffalo. Twenty females and 6 males participated in this study. Material & Methods Using the Diagnostic Criteria for Temporomandibular Disorders (DC-TMD), participants were diagnostically categorized. Subjects used a custom monitoring system, which recorded in–field muscle activities. A factorial model tested for association between independent variable (muscle, time period, MMA level, diagnostic group) effects and the logarithm of MMA. Greenhouse–Geisser test was used to determine any statistically significant associations (p ≤ 0.003). Results No statistically significant association was found among four-way, three-way, and two-way analyses. However, among the main effects, range of magnitudes was the only variable to be statistically significant. Although the data suggest a trend of increased masseter MMA in the pain-related TMD diagnoses group both during awake and sleep time periods, such observation is not maintained for the temporalis muscle. In addition, temporalis MMA was found to be higher in the pain-related TMD diagnoses group only at extreme activity levels (<25% and ≥80% ranges). Conclusion This data support the association between masticatory muscle hyperactivity and painful-TMD conditions. PMID:25865542

  4. A Comparison of the Deep Cervical Flexor Muscle Thicknesses in Subjects with and without Neck Pain during Craniocervical Flexion Exercises.

    Science.gov (United States)

    Jun, Ilsub; Kim, Kyoung

    2013-11-01

    [Purpose] The purpose of the present study was to examine the amount of change in the thicknesses of the deep cervical flexor (DCF) and sternocleidomastoid (SCM) muscles in subjects with neck pain and subjects without neck pain during craniocervical flexion exercise (CCFE). [Subjects] The total number of subjects was 40, comprising 20 in the no-pain group (males 11, females 9) and 20 in the pain group (males 8, females 12). [Methods] Muscle images were obtained using ultrasound, and the thicknesses of the individual muscles were measured using the NIH ImageJ software. [Results] During CCFE, as pressure increased, the no-pain group recruited the DCF more than the pain group, while the pain group recruited the SCM more. [Conclusion] Selective DCF contraction exercises are considered very useful in the treatment of patients with neck pain.

  5. Muscle synergies during incremental rowing VO2max test of collegiate rowers and untrained subjects.

    Science.gov (United States)

    Shaharudin, Shazlin; Agrawal, Sunil

    2016-09-01

    The purpose of this study was to evaluate the muscle synergies during incremental rowing VO2 max Test of collegiate rowers and untrained subjects. As a power endurance sport, high aerobic capacity was one of the determinants of rowing performance. The modulation of muscle recruitment patterns following specific physiological demands was an indication of the robustness of muscle synergies composition which was overlooked in previous studies. Ten male collegiate rowers and physically active untrained subjects were recruited. Muscle synergies were extracted from 16 rowing-specific muscles using Principal Component Analysis with varimax rotation. Incremental rowing VO2 max Test was performed on slides ergometer (SE). Rowing performance and physiological variables were analyzed. Rowers exerted greater power output, more energy expenditure and better rowing economy compared to untrained subjects. Rowers preferred to row slower with longer strokes compared to the untrained subjects. Three muscle synergies with high indices of similarity of waveform patterns were extracted in both groups. Significant association was found between muscle synergies and rowing economy. The findings of this study showed that muscle synergies were robust during aerobic-dominant activity for collegiate rowers and untrained subjects. Rowers and coaches could utilize the findings by emphasizing on muscle coordination training, which may enhance the rowing economy.

  6. Influence of Isometric Exercise Training on Quadriceps Muscle Architecture and Strength in Obese Subjects with Knee Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Waleed S Mahmoud

    2017-03-01

    Full Text Available Obese individuals have reduced quadriceps muscle strength relative to body mass that may increase the rate of progression of knee osteoarthritis (OA. The purpose of this study was to evaluate the effects of isometric exercise training on quadriceps muscle architecture and strength in obese subjects with knee osteoarthritis. Methods: Fortyfour obese male subjects aged 40–65 years diagnosed with knee osteoarthritis were randomly assigned into group A (n=32 and group B (n=12. Group A subjects performed a 12-week isometric exercise program. Group B subjects did not participate in any exercise program and maintained their ordinary activities for the same period. Both groups received the same conventional physical therapy program including hot packs and therapeutic ultrasonic. Muscle thickness, pennation angles and fascicle length of the vastus lateralis (VL muscle of the affected knee were measured at rest by B-mode ultrasonography. Maximal voluntary isometric knee extension torque (MVIC of the affected knee was measured using an isokinetic dynamometer. Knee pain and function were evaluated using visual analogue pain scale (VAS and Western Ontario and McMaster Universities Arthritis Index (WOMAC. All variables were evaluated before and the end of the intervention period for both groups. Results: at the end of the program, group A subjects showed significant improvements compared with group B subjects regarding MVIC and muscle architecture parameters (p<0.05. Also, there was significant improvement in post-test VAS and WOMAC scores in group A subjects compared to group B subjects (p<0.05. Conclusion: A 12-week quadriceps isometric training program improves knee pain and quadriceps muscle strength and architecture in obese subjects with knee OA. These results indicate that isometric training should be regarded as a proper exercise intervention for obese patients with knee OA.

  7. Biomarkers of mitochondrial content in skeletal muscle of healthy young human subjects

    DEFF Research Database (Denmark)

    Larsen, Steen; Nielsen, Joachim; Neigaard Nielsen, Christina

    2012-01-01

    Skeletal muscle mitochondrial content varies extensively between human subjects. Biochemical measures of mitochondrial proteins, enzyme activities and lipids are often used as markers of mitochondrial content and muscle oxidative capacity (OXPHOS). The purpose of this study was to determine how...... closely associated these commonly used biochemical measures are to muscle mitochondrial content and muscle oxidative capacity (OXPHOS).Sixteen young healthy male subjects were recruited for this study. Subjects completed a graded exercise test to determine maximal oxygen uptake (VO(2peak)) and muscle......, mitochondrial DNA content, complex I-V protein content, and complex I-IV activity. Spearman correlation coefficient tests and Lin's concordance tests were applied to assess the absolute and relative association between the markers and mitochondrial content or OXPHOS.Subjects had a large range in VO(2peak...

  8. Electromyographic Evaluation of the Effect of Lined Dentures on Masticatory Muscle Activity in Edentulous Subjects

    Science.gov (United States)

    Srivastava, Shitij; Gaur, Abhishek; Dupare, Arun; Rastogi, Shiksha; Kamatagi, Laxmikant

    2015-01-01

    Aim The purpose of this study was to examine changes in relative electromyographic (EMG) activities of temporal and masseter muscles after relining the dentures with silicone and acrylic-resin based denture liners. Materials and Methods Conventional complete dentures were fabricated for 20 edentulous patients. One month after completing adjustments of the dentures, electromyography of the masseter and temporalis muscle during maximum intercuspation was recorded. The dentures were then relined with a silicone denture liner and after an adaptation period of one month, were again subjected for electromyographic evaluation. Further, the dentures were relined with acrylic denture liner and subjected to electromyographic evaluation. Data was analysed using Statistical Package for Social Sciences (SPSS) version 15.0. Intergroup comparisons were done using ANOVA followed by post-hoc assessments using Tukey HSD test. Results Mean amplitude and duration with conventional dentures was found to be significantly lower as compared to silicone lined and acrylic lined dentures for all the comparisons. Statistically, no significant difference between silicone lined and acrylic lined dentures was observed for any of the comparisons. Conclusion Within the limitations of this experimental design, it was concluded that relining significantly increases electromyographic activity of the masseter and temporalis muscles. Thus, resulting in an improved biting force, chewing efficiency and masticatory performance. There were no significant differences between silicone and acrylic based denture liners for both electromyographic variables. PMID:26436054

  9. Repeated static contractions increase mitochondrial vulnerability toward oxidative stress in human skeletal muscle

    DEFF Research Database (Denmark)

    Sahlin, Kent; Nielsen, Jens Steen; Mogensen, Martin

    2006-01-01

    +) kinetics in human muscle. Ten male subjects performed five bouts of static knee extension with 10-min rest in between. Each bout of RSC (target torque 66% of maximal voluntary contraction torque) was maintained to fatigue. Muscle biopsies were taken preexercise and 0.3 and 24 h postexercise from vastus......Repeated static contractions (RSC) induce large fluctuations in tissue oxygen tension and increase the generation of reactive oxygen species (ROS). This study investigated the effect of RSC on muscle contractility, mitochondrial respiratory function, and in vitro sarcoplasmic reticulum (SR) Ca(2......, decreased mitochondrial efficiency (phosphorylated ADP-to-oxygen consumed ratio), and increased noncoupled respiration (HPX/Con post- vs. preexercise). SR Ca(2+) uptake rate was lower 0.3 vs. 24 h postexercise, whereas SR Ca(2+) release rate was unchanged. RSC resulted in long-lasting changes in muscle...

  10. Muscle Synergies of Untrained Subjects during 6 min Maximal Rowing on Slides and Fixed Ergometer.

    Science.gov (United States)

    Shaharudin, Shazlin; Zanotto, Damiano; Agrawal, Sunil

    2014-12-01

    The slides ergometer (SE) was an improvisation from fixed ergometer (FE) to bridge the gap of mechanics between ergometer rowing and on-water rowing. The specific mechanical constraints of these two types of ergometers may affect the pattern of muscle recruitment, coordination and adaptation. The main purpose of this study was to evaluate the muscle synergy during 6 minutes maximal rowing on slides (SE) and fixed ergometers (FE). The laterality of muscle synergy was also examined. Surface electromyography activity, power output, heart rate, stroke length and stroke rate were analyzed from nine physically active subjects to assess the rowing performance. Physically active subjects, who were not specifically trained in rowing, were chosen to exclude the training effect on muscle synergy. Principal component analysis (PCA) with varimax rotation was applied to extract muscle synergy. Three muscle synergies were sufficient to explain the majority of variance in SE (94.4 ± 2.2 %) and FE (92.8 ± 1.7 %). Subjects covered more rowing distance, exerted greater power output and attained higher maximal heart rate during rowing on SE than on FE. The results proved the flexibility of muscle synergy to adapt to the mechanical constraints. Rowing on SE emphasized on bi-articular muscles contrary to rowing on FE which relied on cumulative effect of trunk and upper limb muscles during propulsive phase. Key pointsThree muscle synergies were extracted during maximal rowing on both fixed and slides ergometerUntrained subjects emphasized leg muscles while rowing on SEUntrained subjects focused on back muscles during FE rowing.

  11. Effects of experimental muscle pain on shoulder-abduction force steadiness and muscle activity in healthy subjects

    DEFF Research Database (Denmark)

    Bandholm, Thomas Quaade; Rasmussen, Lars; Aagaard, Per

    2007-01-01

    We previously demonstrated that the steadiness of shoulder abduction is reduced in patients with subacromial impingement syndrome (SIS), which might be related to shoulder pain associated with the SIS. The aim of the present study was to examine the acute effects of experimental shoulder muscle...... pain on shoulder motor function in healthy subjects. The fluctuations in exerted force (force steadiness) and electromyographic (EMG) activity from eight shoulder muscles were determined during sub-maximal isometric and dynamic contractions with the shoulder abductors in nine healthy subjects (27.......7 +/- 4.2 years, mean +/- 1 SD) before, during and after experimental pain induction. Experimental pain was induced by bolus injections of 6% hypertonic saline into the supraspinatus muscle. Experimental muscle pain reduced shoulder-abduction force steadiness on average by 21% during isometric...

  12. Nutritional strategies of physically active subjects with muscle dysmorphia

    OpenAIRE

    Contesini, Nadir ; Adami, Fernando ; Blake, Márcia ; MONTEIRO, Carlos Bandeira de Mello; Abreu, Luiz C; Valenti, Vitor E; Almeida, Fernando S; Luciano, Alexandre P; Cardoso, Marco A; Benedet, Jucemar ; de Assis Guedes de Vasconcelos, Francisco ; Leone, Claudio ; Frainer, Deivis Elton Schlickmann 

    2013-01-01

    Abstract Background The aim of this study was to identify dietary strategies for physically active individuals with muscle dysmorphia based on a systematic literature review. Method References were included if the study population consisted of adults over 18 years old who were p...

  13. Muscle fatigue evaluation of astronaut upper limb based on sEMG and subjective assessment

    Science.gov (United States)

    Zu, Xiaoqi; Zhou, Qianxiang; Li, Yun

    2012-07-01

    All movements are driven by muscle contraction, and it is easy to cause muscle fatigue. Evaluation of muscle fatigue is a hot topic in the area of astronaut life support training and rehabilitation. If muscle gets into fatigue condition, it may reduce work efficiency and has an impact on psychological performance. Therefore it is necessary to develop an accurate and usable method on muscle fatigue evaluation of astronaut upper limb. In this study, we developed a method based on surface electromyography (sEMG) and subjective assessment (Borg scale) to evaluate local muscle fatigue. Fifteen healthy young male subjects participated in the experiment. They performed isometric muscle contractions of the upper limb. sEMG of the biceps brachii were recorded during the entire process of isotonic muscle contraction and Borg scales of muscle fatigue were collected in certain times. sEMG were divided into several parts, and then mean energy of each parts were calculated by the one-twelfth band octave method. Equations were derived based on the relationship between the mean energy of sEMG and Borg scale. The results showed that cubic curve could describe the degree of local muscle fatigue, and could be used to evaluate and monitor local muscle fatigue during the entire process.

  14. Subject-specific musculoskeletal modeling in the evaluation of shoulder muscle and joint function.

    Science.gov (United States)

    Wu, Wen; Lee, Peter V S; Bryant, Adam L; Galea, Mary; Ackland, David C

    2016-11-07

    Upper limb muscle force estimation using Hill-type muscle models depends on musculotendon parameter values, which cannot be readily measured non-invasively. Generic and scaled-generic parameters may be quickly and easily employed, but these approaches do not account for an individual subject's joint torque capacity. The objective of the present study was to develop a subject-specific experimental testing and modeling framework to evaluate shoulder muscle and joint function during activities of daily living, and to assess the capacity of generic and scaled-generic musculotendon parameters to predict muscle and joint function. Three-dimensional musculoskeletal models of the shoulders of 6 healthy subjects were developed to calculate muscle and glenohumeral joint loading during abduction, flexion, horizontal flexion, nose touching and reaching using subject-specific, scaled-generic and generic musculotendon parameters. Muscle and glenohumeral joint forces calculated using generic and scaled-generic models were significantly different to those of subject-specific models (pMuscles in generic musculoskeletal models operated further from the plateau of their force-length curves than those of scaled-generic and subject-specific models, while muscles in subject-specific models operated over a wider region of their force length curves than those of the generic or scaled-generic models, reflecting diversity of subject shoulder strength. The findings of this study suggest that generic and scaled-generic musculotendon parameters may not provide sufficient accuracy in prediction of shoulder muscle and joint loading when compared to models that employ subject-specific parameter-estimation approaches. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Resistance exercise increases leg muscle protein synthesis and mTOR signalling independent of sex

    Science.gov (United States)

    Dreyer, Hans C.; Fujita, Satoshi; Glynn, Erin L.; Drummond, Micah J.; Volpi, Elena; Rasmussen, Blake B.

    2010-01-01

    Aim Sex differences are evident in human skeletal muscle as the cross-sectional area of individual muscle fibres is greater in men as compared to women. We have recently shown that resistance exercise stimulates mTOR signalling and muscle protein synthesis in humans during early post-exercise recovery. Therefore, the aim of this study was to determine if sex influences the muscle protein synthesis response during recovery from resistance exercise. Methods Seventeen subjects, 9 male and 8 female, were studied in the fasted state before, during and for two hours following a bout of high-intensity leg resistance exercise. Mixed muscle protein fractional synthetic rate (FSR) was measured using stable isotope techniques and mTOR signalling was assessed by immunoblotting from repeated vastus lateralis muscle biopsy samples. Results Post-exercise muscle protein synthesis increased by 52% in the men and by 47% in the women (P0.05). Akt phosphorylation increased in both groups at 1 hr post-exercise (P0.05). Phosphorylation of mTOR and its downstream effector S6K1 increased significantly and similarly between groups during post-exercise recovery (P<0.05). eEF2 phosphorylation decreased at 1- and 2 hrs post-exercise (P<0.05) to a similar extent in both groups. Conclusion The contraction-induced increase in early post-exercise mTOR signalling and muscle protein synthesis is independent of sex and appears to not be playing a role in the sexual dimorphism of leg skeletal muscle in young men and women. PMID:20070283

  16. Increased Stiffness in Aged Skeletal Muscle Impairs Muscle Progenitor Cell Proliferative Activity.

    Directory of Open Access Journals (Sweden)

    Grégory Lacraz

    Full Text Available Skeletal muscle aging is associated with a decreased regenerative potential due to the loss of function of endogenous stem cells or myogenic progenitor cells (MPCs. Aged skeletal muscle is characterized by the deposition of extracellular matrix (ECM, which in turn influences the biomechanical properties of myofibers by increasing their stiffness. Since the stiffness of the MPC microenvironment directly impacts MPC function, we hypothesized that the increase in muscle stiffness that occurs with aging impairs the behavior of MPCs, ultimately leading to a decrease in regenerative potential.We showed that freshly isolated individual myofibers from aged mouse muscles contain fewer MPCs overall than myofibers from adult muscles, with fewer quiescent MPCs and more proliferative and differentiating MPCs. We observed alterations in cultured MPC behavior in aged animals, where the proliferation and differentiation of MPCs were lower and higher, respectively. These alterations were not linked to the intrinsic properties of aged myofibers, as shown by the similar values for the cumulative population-doubling values and fusion indexes. However, atomic force microscopy (AFM indentation experiments revealed a nearly 4-fold increase in the stiffness of the MPC microenvironment. We further showed that the increase in stiffness is associated with alterations to muscle ECM, including the accumulation of collagen, which was correlated with higher hydroxyproline and advanced glycation end-product content. Lastly, we recapitulated the impaired MPC behavior observed in aging using a hydrogel substrate that mimics the stiffness of myofibers.These findings provide novel evidence that the low regenerative potential of aged skeletal muscle is independent of intrinsic MPC properties but is related to the increase in the stiffness of the MPC microenvironment.

  17. Increased deltoid and abdominal muscle activity during Swiss ball bench press.

    Science.gov (United States)

    Marshall, Paul W M; Murphy, Bernadette A

    2006-11-01

    The swiss is widely used in the recreational training environment as a supplement to conventional resistance training. One such application is to use the swiss ball as a bench support for bench press exercise. There is no evidence to indicate that the use of a swiss ball is beneficial for resistance training exercise. This study investigated muscle activity using surface electromyography of upper-body and abdominal muscles during the concentric and eccentric phases of the bench press on and off a swiss ball. Volunteers for this study were 14 resistance-trained subjects who performed isolated concentric and eccentric bench press repetitions using the 2 test surfaces with a 2-second cadence at a load equivalent to 60% maximum force output. The average root mean square of the muscle activity was calculated for each movement, and perceived exertion during the tasks was collected using a Borg Scale. The results of the study showed that deltoid and abdominal muscle activity was increased for repetitions performed using the swiss ball. Increased deltoid muscle activity supports previous findings for increased activity when greater instability is introduced to the bench press movement. Abdominal muscle activity increases were not hypothesized, but this finding provides scientific evidence for anecdotal reasoning behind swiss ball use as a potential core stability training device.

  18. Young, Healthy Subjects Can Reduce the Activity of Calf Muscles When Provided with EMG Biofeedback in Upright Stance

    Science.gov (United States)

    Vieira, Taian M.; Baudry, Stéphane; Botter, Alberto

    2016-01-01

    Recent evidence suggests the minimization of muscular effort rather than of the size of bodily sway may be the primary, nervous system goal when regulating the human, standing posture. Different programs have been proposed for balance training; none however has been focused on the activation of postural muscles during standing. In this study we investigated the possibility of minimizing the activation of the calf muscles during standing through biofeedback. By providing subjects with an audio signal that varied in amplitude and frequency with the amplitude of surface electromyograms (EMG) recorded from different regions of the gastrocnemius and soleus muscles, we expected them to be able to minimize the level of muscle activation during standing without increasing the excursion of the center of pressure (CoP). CoP data and surface EMG from gastrocnemii, soleus and tibialis anterior muscles were obtained from 10 healthy participants while standing at ease and while standing with EMG biofeedback. Four sensitivities were used to test subjects' responsiveness to the EMG biofeedback. Compared with standing at ease, the two most sensitive feedback conditions induced a decrease in plantar flexor activity (~15%; P < 0.05) and an increase in tibialis anterior EMG (~10%; P < 0.05). Furthermore, CoP mean position significantly shifted backward (~30 mm). In contrast, the use of less sensitive EMG biofeedback resulted in a significant decrease in EMG activity of ankle plantar flexors with a marginal increase in TA activity compared with standing at ease. These changes were not accompanied by greater CoP displacements or significant changes in mean CoP position. Key results revealed subjects were able to keep standing stability while reducing the activity of gastrocnemius and soleus without loading their tibialis anterior muscle when standing with EMG biofeedback. These results may therefore posit the basis for the development of training protocols aimed at assisting subjects in

  19. Muscle Synergies of Untrained Subjects during 6 min Maximal Rowing on Slides and Fixed Ergometer

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    Shazlin Shaharudin

    2014-12-01

    Full Text Available The slides ergometer (SE was an improvisation from fixed ergometer (FE to bridge the gap of mechanics between ergometer rowing and on-water rowing. The specific mechanical constraints of these two types of ergometers may affect the pattern of muscle recruitment, coordination and adaptation. The main purpose of this study was to evaluate the muscle synergy during 6 minutes maximal rowing on slides (SE and fixed ergometers (FE. The laterality of muscle synergy was also examined. Surface electromyography activity, power output, heart rate, stroke length and stroke rate were analyzed from nine physically active subjects to assess the rowing performance. Physically active subjects, who were not specifically trained in rowing, were chosen to exclude the training effect on muscle synergy. Principal component analysis (PCA with varimax rotation was applied to extract muscle synergy. Three muscle synergies were sufficient to explain the majority of variance in SE (94.4 ± 2.2 % and FE (92.8 ± 1.7 %. Subjects covered more rowing distance, exerted greater power output and attained higher maximal heart rate during rowing on SE than on FE. The results proved the flexibility of muscle synergy to adapt to the mechanical constraints. Rowing on SE emphasized on bi-articular muscles contrary to rowing on FE which relied on cumulative effect of trunk and upper limb muscles during propulsive phase.

  20. Abnormal Cortex-Muscle Interactions in Subjects with X-linked Kallmann's Syndrome and Mirror Movements

    Science.gov (United States)

    Farmer, S. F.; Harrison, L. M.; Mayston, M. J.; Parekh, A.; James, L. M.; Stephens, J. A.

    2004-01-01

    X-linked Kallmann's (XKS) subjects, who display mirror movements, have abnormal corticospinal tracts which innervate motoneurons of the left and right distal muscles of the upper limb. The size of the abnormal ipsilateral projection is variable. We have used coherence and cumulant analysis between EEG and first dorsal interosseous muscle (1DI) EMG…

  1. Endurance training increases the efficiency of rat skeletal muscle mitochondria.

    Science.gov (United States)

    Zoladz, Jerzy A; Koziel, Agnieszka; Woyda-Ploszczyca, Andrzej; Celichowski, Jan; Jarmuszkiewicz, Wieslawa

    2016-10-01

    Endurance training enhances mitochondrial oxidative capacity, but its effect on mitochondria functioning is poorly understood. In the present study, the influence of an 8-week endurance training on the bioenergetic functioning of rat skeletal muscle mitochondria under different assay temperatures (25, 35, and 42 °C) was investigated. The study was performed on 24 adult 4-month-old male Wistar rats, which were randomly assigned to either a treadmill training group (n = 12) or a sedentary control group (n = 12). In skeletal muscles, endurance training stimulated mitochondrial biogenesis and oxidative capacity. In isolated mitochondria, endurance training increased the phosphorylation rate and elevated levels of coenzyme Q. Moreover, a decrease in mitochondrial uncoupling, including uncoupling protein-mediated proton leak, was observed after training, which could explain the increased reactive oxygen species production (in nonphosphorylating mitochondria) and enhanced oxidative phosphorylation efficiency. At all studied temperatures, endurance training significantly augmented H2O2 production (and coenzyme Q reduction level) in nonphosphorylating mitochondria and decreased H2O2 production (and coenzyme Q reduction level) in phosphorylating mitochondria. Endurance training magnified the hyperthermia-induced increase in oxidative capacity and attenuated the hyperthermia-induced decline in oxidative phosphorylation efficiency and reactive oxygen species formation of nonphosphorylating mitochondria via proton leak enhancement. Thus, endurance training induces both quantitative and qualitative changes in muscle mitochondria that are important for cell signaling as well as for maintaining muscle energy homeostasis, especially at high temperatures.

  2. Increased motor cortex excitability during motor imagery in brain-computer interface trained subjects

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    Olesya eMokienko

    2013-11-01

    Full Text Available Background: Motor imagery (MI is the mental performance of movement without muscle activity. It is generally accepted that MI and motor performance have similar physiological mechanisms.Purpose: To investigate the activity and excitability of cortical motor areas during MI in subjects who were previously trained with an MI-based brain-computer interface (BCI.Subjects and methods: Eleven healthy volunteers without neurological impairments (mean age, 36 years; range: 24–68 years were either trained with an MI-based BCI (BCI-trained, n = 5 or received no BCI training (n = 6, controls. Subjects imagined grasping in a blocked paradigm task with alternating rest and task periods. For evaluating the activity and excitability of cortical motor areas we used functional MRI and navigated transcranial magnetic stimulation (nTMS.Results: fMRI revealed activation in Brodmann areas 3 and 6, the cerebellum, and the thalamus during MI in all subjects. The primary motor cortex was activated only in BCI-trained subjects. The associative zones of activation were larger in non-trained subjects. During MI, motor evoked potentials recorded from two of the three targeted muscles were significantly higher only in BCI-trained subjects. The motor threshold decreased (median = 17% during MI, which was also observed only in BCI-trained subjects.Conclusion: Previous BCI training increased motor cortex excitability during MI. These data may help to improve BCI applications, including rehabilitation of patients with cerebral palsy.

  3. Experimental knee joint pain during strength training and muscle strength gain in healthy subjects

    DEFF Research Database (Denmark)

    Sørensen, T J; Langberg, Henning; Hodges, P W

    2012-01-01

    Knee joint pain and reduced quadriceps strength are cardinal symptoms in many knee pathologies. In people with painful knee pathologies, quadriceps exercise reduces pain, improves physical function, and increases muscle strength. A general assumption is that pain compromises muscle function and t...... and thus may prevent effective rehabilitation. This study evaluated the effects of experimental knee joint pain during quadriceps strength training on muscle strength gain in healthy individuals.......Knee joint pain and reduced quadriceps strength are cardinal symptoms in many knee pathologies. In people with painful knee pathologies, quadriceps exercise reduces pain, improves physical function, and increases muscle strength. A general assumption is that pain compromises muscle function...

  4. Normal mitochondrial function and increased fat oxidation capacity in leg and arm muscles in obese humans

    DEFF Research Database (Denmark)

    Ara, I; Larsen, S; Stallknecht, Bente Merete

    2011-01-01

    Aim/hypothesis:The aim of this study was to investigate mitochondrial function, fibre-type distribution and substrate oxidation during exercise in arm and leg muscles in male postobese (PO), obese (O) and age- and body mass index (BMI)-matched control (C) subjects. The hypothesis of the study...... deltoideus (m. deltoideus) and m. vastus lateralis muscles. Fibre-type composition, enzyme activity and O(2) flux capacity of saponin-permeabilized muscle fibres were measured, the latter by high-resolution respirometry.Results:During the graded exercise tests, peak fat oxidation during leg cycling......, and plasma leptin was higher in O than in PO and C.Conclusions:In O subjects, maximal fat oxidation during exercise and the eliciting relative exercise intensity are increased. This is associated with higher intramuscular triglyceride levels and higher resting non esterified fatty acid (NEFA) concentrations...

  5. The role of hyperplasia on the increase of skeletal muscle

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    Victor Hugo Maciel Meloni

    2005-06-01

    Full Text Available Skeletal muscle hypertrophy is resulted from the individual increase of the fiber cross-sectional area. This adaptative phenomenon is normally observed in the muscle tissue submitted to a regimen of physical exercises, like strength training. The degree of muscular hypertrophy is directly related to the type of exercise and its intensity. Strength training normally produces a hypertrophy of greater magnitude when compared to other types of physical exercise. However, it is possible that there is another adaptive mechanism contributing for increasing skeletal muscle size. This mechanism is called hyperplasia, and can be defined as an increase in the cells, or fibers, number in the muscle. This brief review aims to verify the role of hyperplasia in the increase of skeletal muscle size. RESUMO A hipertrofia do músculo esquelético é resultado do aumento individual da área transversal da fibra. Este fenômeno adaptativo é comumente observado no tecido muscular submetido à um regime de exercícios físicos, como o treinamento de força. O grau de hipertrofia muscular está diretamente relacionado ao tipo de exercício e sua intensidade. O treinamento de força normalmente produz uma hipertrofia de maior magnitude, quando comparada aos outros tipos de exercício físico. Todavia, é provável que haja outro mecanismo adaptativo contribuindo para a hipertrofia do músculo esquelético. Este mecanismo chama-se hiperplasia, e pode ser traduzida por um aumento no número de células, ou fibras musculares em relação ao número original. Este breve resumo tem por objetivo verificar qual é o papel da hiperplasia na hipertrofia do músculo esquelético.

  6. Individual differences in the cardiovascular responses to tonic muscle pain: parallel increases or decreases in muscle sympathetic nerve activity, blood pressure and heart rate.

    Science.gov (United States)

    Fazalbhoy, Azharuddin; Birznieks, Ingvars; Macefield, Vaughan G

    2012-10-01

    We recently showed that acute muscle pain, induced by bolus intramuscular injection of hypertonic saline, causes a sustained increase in muscle sympathetic nerve activity (MSNA) and a modest increase in blood pressure and heart rate. However, it is not known whether long-lasting (tonic) pain, which more closely resembles chronic pain, causes a sustained increase in MSNA and blood pressure. We tested this hypothesis by recording MSNA in 12 healthy subjects. Tonic pain was induced for ~60 min by slow intramuscular infusion of hypertonic saline (7%) into the ipsilateral tibialis anterior muscle. Pain was sustained at a tolerable level (5/10 to 6/10 on a visual analog scale). Seven subjects showed progressive increases in mean MSNA amplitude during tonic pain, increasing to 154 ± 17% (SEM) at 45 min and remaining essentially constant for the duration of the infusion. In these subjects, blood pressure and heart rate also increased. Conversely, for the other five subjects MSNA showed a progressive decline, with a peak fall of 67 ± 11% at 40 min; blood pressure and heart rate also fell in these subjects. We conclude that tonic muscle pain has long-lasting effects on the sympathetic control of blood pressure, causing a sustained increase in some subjects yet a sustained decrease in others. This may have implications for individual differences in the cardiovascular consequences of chronic pain.

  7. Acute resistance exercise reduces increased gene expression in muscle atrophy of ovariectomised arthritic rats

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    Roberto Furlanetto Jr

    2017-02-01

    Full Text Available Objective: We studied the effect of resistance exercise (RE on mRNA levels of atrogin-1, MuRF-1, and myostatin in the gastrocnemius muscle of arthritic rats after loss of ovarian function (LOF. Material and methods : Thirty female Wistar rats (nine weeks old, 195.3 ±17.4 grams were randomly allocated into five groups: control group (CT-Sham; n = 6; group with rheumatoid arthritis (RA; n = 6; group with rheumatoid arthritis subjected to RE (RAEX; n = 6; ovariectomy group with rheumatoid arthritis (RAOV; n = 6; and an ovariectomy group with rheumatoid arthritis subjected to RE (RAOVEX; n = 6. After 15 days of intra-articular injections with Met-BSA the animals were subjected to RE and six hours after workout were euthanised. Results : The rheumatoid arthritis provoked reduction in the cross-sectional area (CSA of muscle fibres, but the CSA was lower in the RAOV when compared to the RA groups. Skeletal muscle atrogin-1 mRNA level was increased in arthritic rats (RA and RAOV, but the atrogin-1 level was higher in RAOV group when compared to other arthritic groups. The Muscle MuRF-1 mRNA level was also increased in the RAOV group. The increased atrogin-1 and MuRF-1 mRNA levels were lower in the RAOVEX group than in the RAOV group. The myostatin mRNA level was similar in all groups, except for the RAOVEX group, in which it was lower than the other groups. Conclusions : LOF results in increased loss of skeletal muscle-related ubiquitin ligases (atrogin-1 and MuRF-1. However, the RE reduces the atrogin-1, MuRF-1, and myostatin mRNA levels in muscle of arthritic rats affected by LOF.

  8. Clenbuterol increases muscle fiber size and GATA-2 protein in rat skeletal muscle in utero.

    Science.gov (United States)

    Downie, Diane; Delday, Margaret I; Maltin, Charlotte A; Sneddon, Alan A

    2008-05-01

    Certain beta(2)-adrenoceptor agonists, such as clenbuterol, are known to elicit a muscle-specific anabolism or hypertrophy in both normal and catabolic muscle in a wide variety of species. However, the underlying mechanism(s) of the beta(2)-agonist-induced anabolism remains unclear. This study aimed to determine the effects of clenbuterol administration in utero on skeletal muscle and to examine the underlying molecular mechanisms. Pregnant rats were fed clenbuterol (2 mg/kg diet) from Day 4 of gestation (4 dg) until weanling and fetal samples were taken from 13.5, 15.5, 17.5, and 19.5 dg and from 1d neonatal pups. Muscles were analyzed for total DNA, RNA and protein and sections examined morphologically for changes in muscle development. Western and immunohistochemical analyses were performed to identify changes in known myogenic signaling proteins. Clenbuterol increased the size of both fast and slow fibers in utero which was associated with a decreased DNA:protein ratio (28%) and an increased RNA:DNA ratio (36%). Additionally, drug treatment in utero induced a decrease in the fast:slow fiber ratio (38%). These myogenic changes were correlated with an increase in the GATA-2 hypertrophic transcription factor at both 17.5 dg (by 250%) and 19.5 dg (by 40%) in fetuses from clenbuterol treated dams. In addition, drug treatment resulted in increased membrane association of PKC-micro at 17.5 dg (325%) and increased PKC-alpha cytosolic abundance (40%) and PKC-theta membrane abundance at 19.5 dg (250%). These results are the first demonstration that beta(2)-agonists such as clenbuterol may act through upregulating the GATA-2 transcription factor and implicate certain PKC isoforms in the drug-induced regulation of skeletal muscle development. (c) 2007 Wiley-Liss, Inc.

  9. Decreased muscle mass in Korean subjects with intracranial arterial stenosis: The Kangbuk Samsung Health Study.

    Science.gov (United States)

    Jung, Ho-Jung; Jung, Hwanseok; Lee, Taeyoung; Kim, Jongho; Park, Jongsin; Kim, Hacsoo; Cho, Junghwan; Lee, Won-Young; Park, Sung-Woo; Rhee, Eun-Jung; Oh, Hyung-Geun

    2017-01-01

    Intracranial arterial stenosis (ICAS) is a common cause of ischemic stroke in Asians. Decreased muscle mass is one of the major causes of chronic disease in adults. The purpose of this study was to analyze the relationship between muscle mass and ICAS in Korean adults. For this study, we selected a total of 10,530 participants (mean age, 43.3 years; 8558 men) in a health screening program, for whom transcranial Doppler (TCD) ultrasound was used to detect >50% ICAS based on criteria modified from the stroke outcomes and neuroimaging of intracranial atherosclerosis trial. Body composition was evaluated by bioelectrical impedance analysis (BIA). Skeletal muscle index (SMI) was calculated with muscle mass/weight (kg) * 100. Among the total patient population, 322 (3.1%) subjects had ICAS. Subjects with ICAS were older, and had higher mean values for fasting glucose, body mass index and blood pressure compared with those without ICAS. Subjects with ICAS had significantly lower muscle mass, SMI and higher percent body fat compared with those without ICAS. In logistic regression analysis, the subjects in the highest tertile of muscle mass had the lowest odds ratio for ICAS with the lowest tertile group of muscle mass as the reference group even after adjusting for age, systolic blood pressure, fasting blood glucose, sex, smoking and exercise (OR 0.650, 95% CI 0.442-0.955). Subjects with ICAS had significantly decreased muscle mass compared with those without ICAS in Korean adults. The risk for ICAS was lower in subjects with higher muscle mass. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Young, healthy subjects can reduce the activity of calf muscles when provided with EMG biofeedback in upright stance

    Directory of Open Access Journals (Sweden)

    Taian M. Vieira

    2016-04-01

    Full Text Available Recent evidence suggests the minimisation of muscular effort rather than of the size of bodily sway may be the primary, nervous system goal when regulating the human, standing posture. Different programs have been proposed for balance training; none however has been focused on the activation of postural muscles during standing. In this study we investigated the possibility of minimising the activation of the calf muscles during standing through biofeedback. By providing subjects with an audio signal that varied in amplitude and frequency with the amplitude of surface electromyograms (EMG recorded from different regions of the gastrocnemius and soleus muscles, we expected them to be able to minimise the level of muscle activation during standing without increasing the excursion of the centre of pressure (CoP. CoP data and surface EMG from gastrocnemii, soleus and tibialis anterior muscles were obtained from ten healthy participants while standing at ease and while standing with EMG biofeedback. Four sensitivities were used to test subjects’ responsiveness to the EMG biofeedback. Compared with standing at ease, the two most sensitive feedback conditions induced a decrease in plantar flexor activity (~15%; P<0.05 and an increase in tibialis anterior EMG (~10%; P<0.05. Furthermore, CoP mean position significantly shifted backward (~30 mm. In contrast, the use of less sensitive EMG biofeedback resulted in a significant decrease in EMG activity of ankle plantar flexors with a marginal increase in TA activity compared with standing at ease. These changes were not accompanied by greater CoP displacements or significant changes in mean CoP position. Key results revealed subjects were able to keep standing stability while reducing the activity of gastrocnemius and soleus without loading their tibialis anterior muscle when standing with EMG biofeedback. These results may therefore posit the basis for the development of training protocols aimed at

  11. Subject-specific modelling of lower limb muscles in children with cerebral palsy.

    Science.gov (United States)

    Oberhofer, K; Stott, N S; Mithraratne, K; Anderson, I A

    2010-01-01

    Recent studies suggest that the architecture of spastic muscles in children with cerebral palsy is considerably altered; however, only little is known about the structural changes that occur other than in the gastrocnemius muscle. In the present study, Magnetic Resonance Imaging (MRI) and subject-specific modelling techniques were used to compare the lengths and volumes of six lower limb muscles between children with cerebral palsy and typically developing children. MRI scans of the lower limbs of two children with spastic hemiplegia cerebral palsy, four children with spastic diplegia cerebral palsy (mean age 9.6 years) and a group of typically developing children (mean age 10.2 years) were acquired. Subject-specific models of six lower limb muscles were developed from the MRI data using a technique called Face Fitting. Muscle volumes and muscle lengths were derived from the models and normalised to body mass and segmental lengths, respectively. Normalised muscle volumes in the children with cerebral palsy were smaller than in the control group with the difference being 22% in the calf muscles, 26% in the hamstrings and 22% in the quadriceps, respectively. Only the differences in the hamstrings and the quadriceps were statistically significant (P=0.036, P=0.038). Normalised muscle lengths in the children with cerebral palsy were significantly shorter (Pmuscle in either group. The present results show that lower limb muscles in ambulatory children with cerebral palsy are significantly altered, suggesting an overall mechanical deficit due to predominant muscle atrophy. Further investigations of the underlying causes of the muscle atrophy are required to better define management and treatment strategies for children with cerebral palsy.

  12. Myoelectric manifestations of jaw elevator muscle fatigue and recovery in healthy and TMD subjects.

    Science.gov (United States)

    Castroflorio, T; Falla, D; Tartaglia, G M; Sforza, C; Deregibus, A

    2012-09-01

    The effects of muscle pain and fatigue on the control of jaw elevator muscles are not well known. Furthermore, the myoelectric manifestations of fatigue and recovery from fatigue in the masticatory muscles are not reported in literature. The main aims of this study were (i) to evaluate the possible use of surface electromyography (sEMG) as an objective measure of fatigue of the jaw elevator muscles, (ii) to compare the myoelectric manifestations of fatigue in the temporalis anterior and masseter muscles bilaterally, (iii) to assess recovery of the investigated muscles after an endurance test and (iv) to compare fatigue and recovery of the jaw elevator muscles in healthy subjects and patients with muscle-related temporomandibular disorders (TMD). The study was performed on twenty healthy volunteers and eighteen patients with muscle-related TMD. An intra-oral compressive-force sensor was used to measure the voluntary contraction forces close to the intercuspal position and to provide visual feedback of submaximal forces to the subject. Surface EMG signals were recorded with linear electrode arrays during isometric contractions at 20%, 40%, 60% and 80% of the maximum voluntary contraction force, during an endurance test and during the recovery phase. The results showed that (i) the slope of the mean power spectral frequency (MNF) and the initial average rectified value (ARV) could be used to monitor fatigue of the jaw elevators, (ii) the temporalis anterior and masseter muscle show the same myoelectric manifestations of fatigue and recovery and (iii) the initial values of MNF and ARV were lower in patients with muscle-related TMD. The assessment of myoelectric manifestations of fatigue in the masticatory muscles may assist in the clinical assessment of TMDs. © 2012 Blackwell Publishing Ltd.

  13. Pairing voluntary movement and muscle-located electrical stimulation increases cortical excitability

    Directory of Open Access Journals (Sweden)

    Mads Jochumsen

    2016-09-01

    Full Text Available Learning new motor skills has been correlated with increased cortical excitability. In this study, different location of electrical stimulation (ES, nerve or muscle, was paired with voluntary movement to investigate if ES paired with voluntary movement a would increase the excitability of cortical projections to tibialis anterior and b if stimulation location mattered. Cortical excitability changes were quantified using motor evoked potentials (MEPs elicited by transcranial magnetic stimulation at varying intensities during four conditions. Twelve healthy subjects performed 50 dorsiflexions at the ankle during nerve or muscle ES at motor threshold. ES alone was delivered 50 times and the movement was performed 50 times. A significant increase in the excitability from pre- to post-intervention (P=0.0061 and pre- to 30 minutes post-intervention (P=0.017 measurements was observed when voluntary movement was paired with muscle ES located at tibialis anterior. An increase of 50±57% and 28±54% in the maximum MEPs was obtained for voluntary movement paired with muscle-located and nerve-located ES, respectively. The maximum MEPs for voluntary movement alone and muscle-located ES alone were -5±28% and 2±42%, respectively. Pairing voluntary movement with muscle-located ES increases excitability of corticospinal projections of tibialis anterior in healthy participants. This finding suggests that active participation during muscle-located ES protocols increases cortical excitability to a greater extent than stimulation alone. The next stage of this research is to investigate the effect in people with stroke. The results may have implications for motor recovery in patients with motor impairments following neurological injury.

  14. Exercises focusing on rotator cuff and scapular muscles do not improve shoulder joint position sense in healthy subjects.

    Science.gov (United States)

    Lin, Yin-Liang; Karduna, Andrew

    2016-10-01

    Proprioception is essential for shoulder neuromuscular control and shoulder stability. Exercise of the rotator cuff and scapulothoracic muscles is an important part of shoulder rehabilitation. The purpose of this study was to investigate the effect of rotator cuff and scapulothoracic muscle exercises on shoulder joint position sense. Thirty-six healthy subjects were recruited and randomly assigned into either a control or training group. The subjects in the training group received closed-chain and open-chain exercises focusing on rotator cuff and scapulothoracic muscles for four weeks. Shoulder joint position sense errors in elevation, including the humerothoracic, glenohumeral and scapulothoracic joints, was measured. After four weeks of exercise training, strength increased overall in the training group, which demonstrated the effect of exercise on the muscular system. However, the changes in shoulder joint position sense errors in any individual joint of the subjects in the training group were not different from those of the control subjects. Therefore, exercises specifically targeting individual muscles with low intensity may not be sufficient to improve shoulder joint position sense in healthy subjects. Future work is needed to further investigate which types of exercise are more effective in improving joint position sense, and the mechanisms associated with those changes. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Exercises focusing on rotator cuff and scapular muscles do not improve shoulder joint position sense in healthy subjects

    Science.gov (United States)

    Lin, Yin-Liang; Karduna, Andrew

    2016-01-01

    Proprioception is essential for shoulder neuromuscular control and shoulder stability. Exercise of the rotator cuff and scapulothoracic muscles is an important part of shoulder rehabilitation. The purpose of this study was to investigate the effect of rotator cuff and scapulothoracic muscle exercises on shoulder joint position sense. Thirty-six healthy subjects were recruited and randomly assigned into either a control or training group. The subjects in the training group received closed-chain and open-chain exercises focusing on rotator cuff and scapulothoracic muscles for four weeks. Shoulder joint position sense errors in elevation, including the humerothoracic, glenohumeral and scapulothoracic joints, was measured. After four weeks of exercise training, strength increased overall in the training group, which demonstrated the effect of exercise on the muscular system. However, the changes in shoulder joint position sense errors in any individual joint of the subjects in the training group were not different from those of the control subjects. Therefore, exercises specifically targeting individual muscles with low intensity may not be sufficient to improve shoulder joint position sense in healthy subjects. Future work is needed to further investigate which types of exercise are more effective in improving joint position sense, and the mechanisms associated with those changes. PMID:27475714

  16. Immediate effects of hamstring muscle stretching on pressure pain sensitivity and active mouth opening in healthy subjects.

    Science.gov (United States)

    Bretischwerdt, Cristina; Rivas-Cano, Luis; Palomeque-del-Cerro, Luis; Fernández-de-las-Peñas, César; Alburquerque-Sendín, Francisco

    2010-01-01

    This study analyzed the immediate effect of hamstring muscle stretching on pressure pain sensitivity over the masseter and the upper trapezius muscles and maximum active mouth opening in healthy subjects. One hundred twenty volunteers, 70 males and 50 females, between the ages of 22 and 47, were randomly divided into 3 groups: group 1 (control group) that did not receive any intervention, group 2 where a unilateral hamstring muscle stretching was applied, and group 3 where a bilateral stretching was applied. Pressure pain thresholds (PPTs) were bilaterally assessed over the masseter and upper trapezius muscles pre- and 5 minutes posttreatment by an assessor blinded to group assignment. Maximum mouth opening was also assessed pre- and 5 minutes posttreatment. Mixed-model analyses of variance (ANOVAs) were used to examine the effects of the intervention. The primary analysis was the group x time interaction. The ANOVA revealed significant group x time interaction for changes in PPTs over the upper trapezius (F = 4.5; P = .01) and masseter (F = 6.3; P = .002) muscles. Pre-post effect sizes were moderate (0.5 >d > 0.7) for both stretching groups and negative (d 0.7) for both stretching groups and negative (d stretching of the hamstring musculature produced an immediate increase in PPTs over both masseter and upper trapezius muscles in healthy subjects. Copyright 2010 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

  17. Effect of bolus hardness on the chewing pattern and activation of masticatory muscles in subjects with normal dental occlusion.

    Science.gov (United States)

    Piancino, Maria Grazia; Bracco, Pietro; Vallelonga, Teresa; Merlo, Andrea; Farina, Dario

    2008-12-01

    The aim of the study was to evaluate the effect of bolus hardness on the kinematic of mastication and jaw-elevator muscle activity in subjects with normal dental occlusion and function. The mandibular motion and the surface EMG envelope of the masseter and temporalis anterior muscles were assessed in twelve subjects during mastication of a soft and hard bolus of the same size. When chewing the hard bolus, the chewing pattern in the frontal plane was significantly higher and wider, with smaller closure angle and higher peak velocity than when chewing the soft bolus. EMG peak amplitude of both the masseter and anterior temporalis muscles was higher for the side of the bolus but the contralateral side increased its activity significantly more than the ipsilateral side when the hardness of the bolus increased (for the masseter, mean+/-SD: 130.4+/-108.1% increase for the contralateral side and 29.6+/-26.9% for the ipsilateral side). Moreover, the peak EMG activity for both muscles occurred more distant from the closure point with hard bolus. The increased activity of the contralateral side may help maintaining the mandibular equilibrium, with indirect participation to the power stroke generated by the chewing-side masseter. The results provide kinematic and EMG adaptations to bolus hardness in healthy subjects and can be used as normative data in the development of methods for early diagnosis of impaired chewing function.

  18. Changes in upper and lower body muscle involvement at increasing double poling velocities: an ecological study.

    Science.gov (United States)

    Zoppirolli, C; Pellegrini, B; Modena, R; Savoldelli, A; Bortolan, L; Schena, F

    2017-11-01

    This study evaluated muscle activity changes in different body compartments during on-snow double poling at increasing velocities. 21 well-trained, male cross-country skiers performed five 3-min double poling trials on a snowy track at 15, 16.5, 18, 19.5, and 21 km/h (set by an audio-pace system). A sixth trial was performed by maintaining a constant maximal speed. Actual skiing velocities were verified using a photocell system. Only 11 subjects met the pre-defined inclusion criteria during the trials and were included in the data analysis. Electromyographical signals from seven muscles, wrist acceleration and heart rate during the last minute of each trial were recorded. Cycle and poling times were measured from acceleration signals; mean muscular activation over a cycle was calculated for each muscle. With increasing double poling velocities from aerobic to maximal intensity (from 65% to 100% of maximal heart rate), upper limb muscles activation was maintained constant (P > 0.05), while trunk and lower limb involvement increased significantly (P < 0.01) with a linear trend. Rectus abdominis and rectus femoris muscles showed the higher rate of change. Trunk and lower limbs provide a progressively greater contribution to the propulsion when increasing double poling velocities are performed, to support the limited capacity of exercise response of upper body muscles. The remarkable rate of involvement of the muscles near the core region of the body becomes strategic to cope with the increased demands of propulsive power. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Membrane leakage and increased content of Na+ -K+ pumps and Ca2+ in human muscle after a 100-km run

    DEFF Research Database (Denmark)

    Overgaard, Kristian; Lindstrøm, Tue; Ingemann-Hansen, Thorsten

    2002-01-01

    content, and plasma concentrations of creatine kinase (CK) and lactate dehydrogenase (LDH). After completion of a 100-km run, significant increases were found in plasma K+ (from 4.0 +/- 0.1 to 5.5 +/- 0.2 mM, P ...During prolonged exercise, changes in the ionic milieu in and surrounding the muscle fibers may lead to fatigue or damage of the muscle and thereby impair performance. In 10 male subjects, we investigated the effects of 100 km running on muscle and plasma electrolyte contents, muscle Na+ -K+ pump...

  20. The influence of specific training on trunk muscle recruitment patterns in healthy subjects during stabilization exercises.

    Science.gov (United States)

    Stevens, Veerle K; Coorevits, Pascal L; Bouche, Katie G; Mahieu, Nele N; Vanderstraeten, Guy G; Danneels, Lieven A

    2007-08-01

    Low back pain is a major problem involving high medical costs, therefore effective prevention strategies are essential. Stabilization exercises seem to facilitate the neuromuscular control of the lumbar spine and may be useful in prevention programs. To investigate whether specific lumbar stabilization training has an effect on muscle recruitment patterns in a healthy population, in the present study 30 subjects were recruited to perform two types of testing exercises, i.e. bridging exercises and exercises in four-point kneeling, both before and after training. Surface electromyographic data of different abdominal and back muscles were obtained. After training, analysis of the relative muscle activity levels (percentage of maximal voluntary isometric contraction) showed a higher activity of the local (segmental-stabilizing) abdominal muscles, but not of the local back muscles; minimal changes in global (torque-producing) muscle activity also occurred. Analysis of the local/global relative muscle activity ratios revealed higher ratios during all exercises after training, although not all differences were significant. These results indicate that muscle recruitment patterns can be changed in healthy subjects by means of a training program that focuses on neuromuscular control. Additional studies are needed to evaluate this type of training as a prevention strategy.

  1. Sympathetic activation by the cold pressor test does not increase the muscle force generation capacity.

    Science.gov (United States)

    Roatta, Silvestro; Farina, Dario

    2011-06-01

    A positive inotropic action by the sympathetic nervous system on skeletal muscles has been observed and investigated in animal and in vitro studies. This action provided a theoretical basis for the putative ergogenic action of catecholamines and adrenergic agonists, although there is no clear evidence of this effect in humans. The aim of this study was to investigate the occurrence of inotropic effects associated to physiological sympathetic activation in healthy subjects. The muscle force capacity was investigated in the tibialis anterior (n = 9 subjects) and in the soleus (n = 9) muscles electrically stimulated with single pulses and double pulses with variable interspike interval (4-1,000 ms) and short pulse trains (frequency: 5-14 Hz) before, during, and after sympathetic activation by the cold pressor test (CPT). CPT significantly decreased by 10.4 ± 7.2 and 10.6 ± 4.4% the force produced by single and double pulse stimulation, respectively, and produced smaller decreases in the force obtained by train stimulation in the tibialis anterior, while no significant changes were observed in either type of contraction in the soleus muscle. CPT failed to induce any increase in the force capacity of the investigated muscles. The prevalent decrease in force evidenced in this study supports the concept that the weakening sympathetic action on type I fiber, already shown to occur in humans, prevails over the putative potentiating action.

  2. Muscle-specific deletion of SOCS3 increases the early inflammatory response but does not affect regeneration after myotoxic injury.

    Science.gov (United States)

    Swiderski, Kristy; Thakur, Savant S; Naim, Timur; Trieu, Jennifer; Chee, Annabel; Stapleton, David I; Koopman, René; Lynch, Gordon S

    2016-01-01

    Muscles of old animals are injured more easily and regenerate poorly, attributed in part to increased levels of circulating pro-inflammatory cytokines. The Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling cascade is a key mediator of inflammatory cytokine action, and signaling via this pathway is increased in muscles with aging. As a negative regulator of JAK/STAT signaling, a key mediator of myogenic proliferation and differentiation, altered expression of suppressor of cytokine signaling (SOCS3) is likely to have important consequences for muscle regeneration. To model this scenario, we investigated the effect of SOCS3 deletion within mature muscle fibers on injury and repair. We tested the hypothesis that reduced SOCS3 function would alter the inflammatory response and impair muscle regeneration after myotoxic injury. Mice with a specific deletion of SOCS3 within mature skeletal muscle fibers were used to assess the effect of SOCS3 deletion on muscle injury and repair. Twelve-week-old or 24-month-old SOCS3 muscle-specific knockout (SOCS3 MKO) mice and littermate controls were either left uninjured or injured with a single injection of notexin (10 μg/ml) into the right tibialis anterior (TA) muscle. At 1, 2, 3, 5, 7, or 14 days post-injury, the right TA muscle was excised and subjected to histological, western immunoblotting, and gene expression analyses. Force production and fatigue were assessed in uninjured muscles and at 7 days post-notexin injury. In uninjured muscles, SOCS3 deletion decreased force production during fatigue but had no effect on the gross or histological appearance of the TA muscles. After notexin injury, deletion of SOCS3 increased STAT3 phosphorylation at day 1 and increased the mRNA expression of the inflammatory cytokine TNF-α , and the inflammatory cell markers F4/80 and CD68 at day 2. Gene expression analysis of the regeneration markers Pax7 , MyoD , and Myogenin indicated SOCS3 deletion had no

  3. Healthy subjects with a family history of alcoholism show increased stimulative subjective effects of alcohol.

    Science.gov (United States)

    Söderpalm Gordh, Anna H V; Söderpalm, Bo

    2011-08-01

    Research has shown that subjects with a family history positive (FHP) of alcoholism are at increased risk for alcoholism and that this group reacts differently to alcohol than family history negative (FHN) subjects. These different levels of sensitivity may make FHP persons more likely to consume alcohol. Here, we tested the hypothesis that subjects FHP for type 1 alcoholism (according to Cloninger) are more sensitive than control subjects to the stimulative, properties of alcohol following a single moderate dose of alcohol. Fifty-one healthy men and women (22 FHP and 29 FHN) participated in 2 laboratory sessions, in which they consumed a beverage containing ethanol (0.6 g/kg in juice) or placebo (juice alone) in a randomized order. Primary dependent measures were self-report questionnaires of mood states. Subjects with family history of type 1 alcoholism showed increased stimulative responses and an elevated positive mood state after ethanol compared to controls. At this moderate dose, ethanol increased stimulative subjective responses in individuals who were "family history positive." This enhanced sensitivity could motivate to exaggerated drinking and thereby increase the risk for developing alcoholism. Copyright © 2011 by the Research Society on Alcoholism.

  4. Estimation of spinopelvic muscles' volumes in young asymptomatic subjects: a quantitative analysis.

    Science.gov (United States)

    Amabile, Celia; Moal, Bertrand; Chtara, Oussama Arous; Pillet, Helene; Raya, Jose G; Iannessi, Antoine; Skalli, Wafa; Lafage, Virginie; Bronsard, Nicolas

    2017-04-01

    Muscles have been proved to be a major component in postural regulation during pathological evolution or aging. Particularly, spinopelvic muscles are recruited for compensatory mechanisms such as pelvic retroversion, or knee flexion. Change in muscles' volume could, therefore, be a marker of greater postural degradation. Yet, it is difficult to interpret spinopelvic muscular degradation as there are few reported values for young asymptomatic adults to compare to. The objective was to provide such reference values on spinopelvic muscles. A model predicting the muscular volume from reduced set of MRI segmented images was investigated. A total of 23 asymptomatic subjects younger than 24 years old underwent an MRI acquisition from T12 to the knee. Spinopelvic muscles were segmented to obtain an accurate 3D reconstruction, allowing precise computation of muscle's volume. A model computing the volume of muscular groups from less than six MRI segmented slices was investigated. Baseline values have been reported in tables. For all muscles, invariance was found for the shape factor [ratio of volume over (area times length): SD muscles' values for a reference population have been reported. A new model predicting the muscles' volumes from a reduced set of MRI slices is proposed. While this model still needs to be validated on other populations, the current study appears promising for clinical use to determine, quantitatively, the muscular degradation.

  5. Effects of laser therapy and Grimaldi's muscle shortening manoeuvre on motor control of subjects with incomplete spinal cord injuries.

    Science.gov (United States)

    Longo, Diego; Longo, Leonardo; Lippi, Paolo; Cherubini, Giulio; Mangé, Vanessa

    2017-09-30

    From year 2003 we treated positively 251 patients with Traumatic Spinal Cord Injuries (TSCI), using Non-Surgical Laser Therapy (NSLT). In order to increase muscle strength, we have also started using a physical therapy practice called Grimaldi's Muscle Shortening Manoeuvre (GMSM)The goal of our study is to obtain objective data suggesting the real effectiveness of the association of these two treatments. In 2015, 10 patients with incomplete TSCI were enrolled. Further 10 subjects with similar features were included as control group. All patients have subtotal sensory loss and motor paralysis below the level of the lesion. Lasers used were 808, 10600, and 1064 nm, applied with a first cycle of four sessions per day for a total of 20 sessions. The patients participated in specific physical therapy training (GMSM) twice a day, for a total of eight sessions.Each cycle of laser and GMSM was replicated each month. Results were considered positive if sensitivity increased at least two dermatomes per cycle under the level of the lesion. Results in muscle activity (on/off) were regarded as positive if sEMG showed modifications in CNS-muscle. Objective assessment of force displayed encouraging results. After each cycle, patients showed improvements in motor function and voluntary command. Follow-up is positive after 3 months. Associating laser treatment and Grimaldi's Muscle Shortening Manoeuvre (MSM) seems to be effective on muscle strength and motor control in patients affected by subtotal SCI compared to a control group.

  6. Expiratory and expiratory plus inspiratory muscle training improves respiratory muscle strength in subjects with COPD: systematic review.

    Science.gov (United States)

    Neves, Leonardo F; Reis, Manoela H; Plentz, Rodrigo D M; Matte, Darlan L; Coronel, Christian C; Sbruzzi, Graciele

    2014-09-01

    Inspiratory muscle training (IMT) produces beneficial effects in COPD subjects, but the effects of expiratory muscle training (EMT) and EMT plus IMT in ventilatory training are still unclear. The aim of this study was to systematically review the effects of EMT and EMT plus IMT compared to control groups of COPD subjects. This study is a systematic review and meta-analysis. The search strategy included MEDLINE, Embase, LILACS, PEDro, and Cochrane CENTRAL and also manual search of references in published studies on the subject. Randomized trials comparing EMT and EMT plus IMT versus control groups of subjects with COPD were included. The outcomes analyzed were respiratory muscle strength and functional capacity. Two reviewers independently extracted the data. The search retrieved 609 articles. Five studies were included. We observed that EMT provided higher gain in maximum expiratory pressure (P(E(max)) 21.49 cm H2O, 95% CI 13.39-29.59) and maximum inspiratory pressure (P(I(max)) 7.68 cm H2O, 95% CI 0.90-14.45) compared to control groups. There was no significant difference in the 6-min walk test distance (29.01 m, 95% CI -39.62 to 97.65) and dyspnea (0.15, 95% CI -0.77 to 1.08). In relation to EMT plus IMT, we observed that P(E(max)) (31.98 cm H2O, 95% CI 26.93-37.03) and P(I(max)) (27.98 cm H2O, 95% CI 20.10-35.85) presented higher values compared to control groups. EMT and EMT plus IMT improve respiratory muscle strength and can be used as part of the treatment during pulmonary rehabilitation of subjects with severe to very severe COPD. Copyright © 2014 by Daedalus Enterprises.

  7. Muscle oxygen saturation increases during head-up tilt-induced (pre)syncope

    DEFF Research Database (Denmark)

    Lund, A.; Sorensen, H.; Jensen, T. W.

    2017-01-01

    Aim To evaluate whether muscle vasodilatation plays a role for hypotension developed during central hypovolaemia, muscle oxygenation (SmO2) was examined during (pre)syncope induced by head-up tilt (HUT). Skin blood flow (SkBF) and oxygenation (SskinO2) were determined because evaluation of SmO2 may...... be affected by superficial tissue oxygenation. Furthermore, we evaluated cerebral oxygenation (ScO2) and middle cerebral artery mean blood flow velocity (MCAvmean). Methods Twenty healthy male volunteers (median age 24 years; range 19–38) were subjected to passive 50° HUT for 1 h or until (pre)syncope. ScO2......)syncope was associated with an increase in SmO2 despite reduced SskinO2 and SkBF, supporting that muscle vasodilation plays an important role in the circulatory events leading to hypotension during HUT....

  8. A Novel Noninvasive Method for Measuring Fatigability of the Quadriceps Muscle in Noncooperating Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Jesper B. Poulsen

    2015-01-01

    Full Text Available Background. Critical illness is associated with muscle weakness leading to long-term functional limitations. Objectives. To assess the reliability of a novel method for evaluating fatigability of the quadriceps muscle in noncooperating healthy subjects. Methods. On two occasions, separated by seven days, nonvoluntary isometric contractions (twitch and tetanic of the quadriceps femoris muscle evoked by transcutaneous electrical muscle stimulation were recorded in twelve healthy adults. For tetanic contractions, the Fatigue Index (ratio of peak torque values and the slope of the regression line of peak torque values were primary outcome measures. For twitch contractions, maximum peak torque and rise time were calculated. Relative (intraclass correlation, ICC3.1 and absolute (standard error of measurement, SEM reliability were assessed and minimum detectable change was calculated using a 95% confidence interval (MDC95%. Results. The Fatigue Index (ICC3.1, 0.84; MDC95%, 0.12 and the slope of the regression line (ICC3.1, 0.99; MDC95%, 0.03 showed substantial relative and absolute reliability during the first 15 and 30 contractions, respectively. Conclusion. This method for assessing fatigability of the quadriceps muscle produces reliable results in healthy subjects and may provide valuable data on quantitative changes in muscle working capacity and treatment effects in patients who are incapable of producing voluntary muscle contractions.

  9. Leukemia inhibitory factor increases glucose uptake in mouse skeletal muscle

    DEFF Research Database (Denmark)

    Brandt, Nina; O'Neill, Hayley M; Kleinert, Maximilian

    2015-01-01

    INTRODUCTION: Members of the interleukin-6 (IL-6) family, IL-6 and ciliary neurotrophic factor (CNTF) have been shown to increase glucose uptake and fatty acid oxidation in skeletal muscle. However, the metabolic effects of another family member, leukemia inhibitory factor (LIF), are not well...... indicated that Mammalian Target of Rapamycin complex (mTORC) 2, but not mTORC1, also is required for LIF-stimulated glucose uptake. In contrast to CNTF, LIF-stimulation did not alter palmitate oxidation. LIF-stimulated glucose uptake was maintained in EDL from obese insulin resistant mice, whereas soleus...

  10. Metabolic and transcriptional changes in cultured muscle stem cells from low birth weight subjects

    DEFF Research Database (Denmark)

    Hansen, Ninna S; Hjort, Line; Broholm, Christa

    2016-01-01

    CONTEXT/OBJECTIVE: Developmental programming of human muscle stem cells could in part explain why individuals born with low birth weight (LBW) have an increased risk of developing type 2 diabetes (T2D) later in life. We hypothesized that immature muscle stem cell functions including abnormal...

  11. The adipokine leptin increases skeletal muscle mass and significantly alters skeletal muscle miRNA expression profile in aged mice

    Energy Technology Data Exchange (ETDEWEB)

    Hamrick, Mark W., E-mail: mhamrick@mail.mcg.edu [Department of Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Department of Orthopaedic Surgery, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Herberg, Samuel; Arounleut, Phonepasong [Department of Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Department of Orthopaedic Surgery, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); He, Hong-Zhi [Henry Ford Immunology Program, Henry Ford Health System, Detroit, MI (United States); Department of Dermatology, Henry Ford Health System, Detroit, MI (United States); Shiver, Austin [Department of Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Department of Orthopaedic Surgery, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Qi, Rui-Qun [Henry Ford Immunology Program, Henry Ford Health System, Detroit, MI (United States); Department of Dermatology, Henry Ford Health System, Detroit, MI (United States); Zhou, Li [Henry Ford Immunology Program, Henry Ford Health System, Detroit, MI (United States); Department of Dermatology, Henry Ford Health System, Detroit, MI (United States); Department of Internal Medicine, Henry Ford Health System, Detroit, MI (United States); Isales, Carlos M. [Department of Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Department of Orthopaedic Surgery, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); and others

    2010-09-24

    Research highlights: {yields} Aging is associated with muscle atrophy and loss of muscle mass, known as the sarcopenia of aging. {yields} We demonstrate that age-related muscle atrophy is associated with marked changes in miRNA expression in muscle. {yields} Treating aged mice with the adipokine leptin significantly increased muscle mass and the expression of miRNAs involved in muscle repair. {yields} Recombinant leptin therapy may therefore be a novel approach for treating age-related muscle atrophy. -- Abstract: Age-associated loss of muscle mass, or sarcopenia, contributes directly to frailty and an increased risk of falls and fractures among the elderly. Aged mice and elderly adults both show decreased muscle mass as well as relatively low levels of the fat-derived hormone leptin. Here we demonstrate that loss of muscle mass and myofiber size with aging in mice is associated with significant changes in the expression of specific miRNAs. Aging altered the expression of 57 miRNAs in mouse skeletal muscle, and many of these miRNAs are now reported to be associated specifically with age-related muscle atrophy. These include miR-221, previously identified in studies of myogenesis and muscle development as playing a role in the proliferation and terminal differentiation of myogenic precursors. We also treated aged mice with recombinant leptin, to determine whether leptin therapy could improve muscle mass and alter the miRNA expression profile of aging skeletal muscle. Leptin treatment significantly increased hindlimb muscle mass and extensor digitorum longus fiber size in aged mice. Furthermore, the expression of 37 miRNAs was altered in muscles of leptin-treated mice. In particular, leptin treatment increased the expression of miR-31 and miR-223, miRNAs known to be elevated during muscle regeneration and repair. These findings suggest that aging in skeletal muscle is associated with marked changes in the expression of specific miRNAs, and that nutrient

  12. Exercise increases human skeletal muscle insulin sensitivity via coordinated increases in microvascular perfusion and molecular signaling

    DEFF Research Database (Denmark)

    Sjøberg, Kim Anker; Frøsig, Christian; Kjøbsted, Rasmus

    2017-01-01

    Insulin resistance is a major health risk and although exercise clearly improves skeletal muscle insulin sensitivity, the mechanisms are unclear. Here we show that initiation of a euglycemic hyperinsulinemic clamp four hours after single-legged exercise in humans increased microvascular perfusion...

  13. The effects of new taping methods designed to increase muscle strength.

    Science.gov (United States)

    Fukui, Tsutomu; Otake, Yuko; Kondo, Takashi

    2017-01-01

    [Purpose] Although there are several studies on the use of elastic tape to influence muscle strength, results are contradictory and controversial. Our previous studies based on the sliding mechanism between superficial fascia and subcutaneous tissue may help the muscle strength. The purpose of this study was to confirm the effects of new taping methods on muscle strength. [Subjects and Methods] Sixteen healthy male participants took part in this study. Tape was applied on the right gluteus maximus and hip extension strength was determined by an isokinetic evaluation (30°/sec, concentric mode, four conditions). Condition 1: Tape was applied from the muscle insertion to origin; Condition 2: Tape was applied from the origin to insertion; Condition 3: Dummy tape with no direction; Condition 4: No tape was applied. [Results] The mean value of conditions 1-4 were 398.2 ± 24.3 Newton (N), 343.7 ± 25.9 N, 363.7 ± 26.4 N, and 371.3 ± 26.3 N, respectively (mean ± SE). The result of condition 1 was significantly greater compared with the other conditions. [Conclusion] This new method corresponded to a tape direction of insertion-rigin may help to increase the muscle strength.

  14. Electrically induced mechanomyograms reflect inspiratory muscle strength in young or elderly subjects.

    Science.gov (United States)

    Watanabe, Shogo; Nojima, Ippei; Agarie, Yuuna; Watanabe, Tatsunori; Fukuhara, Shinichi; Fujinaga, Takeshi; Oka, Hisao

    2016-11-01

    Respiratory muscle strength has been used as a tool for evaluating respiratory rehabilitation in chronic obstructive pulmonary disease. However, mouth pressure measurement evaluated by maximum expiratory mouth pressure (PEmax) or inspiratory mouth pressure (PImax) offers an indirect method for measuring respiratory muscle strength. We demonstrated the evaluation of diaphragm contractility using a mechanomyogram (MMG), which is the mechanical signal generated by the motion of the diaphragm induced by the electric stimulation of the phrenic nerve. Study participants were 21 young and 20 elderly subjects with no symptoms of respiratory disease. The elderly subjects were divided into non-smoker or smoker groups. The smoker group was defined as subjects having a Brinkman Index of greater than 300. We measured basic spirometric parameters, mouth pressure (PEmax, PImax), and diaphragmatic MMG. Diaphragmatic MMG showed more clear contrast between young subjects and elderly non-smoker or smoker subjects than the conventional method for respiratory muscle contraction (PEmax, PImax). In addition, the diaphragmatic MMG strongly correlated with inspiratory muscle strength. Diaphragmatic MMG may reflect diaphragmatic contractility more directly and sensitively than the conventional method. Copyright © 2016 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.

  15. [Study of diaphragmatic muscle function during abdominal weight in normal subjects].

    Science.gov (United States)

    Monteiro, Sergio G; Pessolano, Fernando A; Suárez, Adrián A; De Vito, Eduardo L

    2012-01-01

    The effects of the abdominal weight with the intention of producing training of the diaphragm, have not been sufficiently evaluated. We studied the function of the diaphragm during the abdominal weight training and during associated changes in the respiratory pattern. Six normal volunteers were studied. Flow at the mouth at functional residual capacity (FRC) was obtained as well as gastric pressure (Pga), esophageal pressure (Pes), thoracic and abdominal movements, maximal inspiratory pressure and mean and maximal transdiaphragmatic pressure (Pdi and Pdi max). Pdi/Pdimax and the diaphragm tension-time index (TTdi) were calculated. Studied steps: normal pattern (NP), abdominal pattern (AP) and weight of 1, 2, 4 and 6 kg with NP and AP as well. We found 1) The AP was facilitated by the abdominal weight, 2) Only with 6 kg (NP and AP) the Pga at FRC increased significantly (p 0.001), 3) the Pdi followed the variations of the Pga and increased with all the AP (p propioception related to the respiratory movements and descent of the diaphragm. The loads on the abdomen produce minor changes in mechanics of the diaphragm (1/3 of the load required to develop fatigue in normal subjects). Al least in normal subjects these changes appear to be insufficient to produce respiratory muscle training.

  16. Serum after traumatic brain injury increases proliferation and supports expression of osteoblast markers in muscle cells.

    Science.gov (United States)

    Cadosch, Dieter; Toffoli, Andrew M; Gautschi, Oliver P; Frey, Sönke P; Zellweger, René; Skirving, Allan P; Filgueira, Luis

    2010-03-01

    Traumatic brain injury is associated with an increased rate of heterotopic ossification within skeletal muscle, possibly as a result of humoral factors. In this study, we investigated whether cells from skeletal muscle adopt an osteoblastic phenotype in response to serum from patients with traumatic brain injury. Serum was collected from thirteen patients with severe traumatic brain injury, fourteen patients with a long-bone fracture, and ten control subjects. Primary cultures of skeletal muscle cells isolated from patients undergoing orthopaedic surgery were performed and characterized with use of immunofluorescence microscopy, reverse transcription-polymerase chain reaction, and Western blot analysis. Proliferation and osteoblastic differentiation were assessed with use of commercial cell assays, Western blot analysis (for Osterix protein), and the Villanueva bone stain. All serum-treated cell populations expressed the osteoblast marker Osterix after one week in culture. Cells treated with serum from all study groups in mineralization medium had increased alkaline phosphatase activity and mineralized nodules within the mesenchymal cell subpopulation after three weeks in culture. Serum from patients with traumatic brain injury induced a significant increase (p = 0.02) in the rate of proliferation of primary skeletal muscle cells (1.87 [95% confidence interval, 1.66 to 2.09]) compared with the rate induced by serum from patients with a fracture (1.42 [95% confidence interval, 1.21 to 1.58]) or by serum from controls (1.35 [95% confidence interval, 1.15 to 1.54]). Human serum supports the osteoblastic differentiation of cells derived from human skeletal muscle, and serum from patients with severe traumatic brain injury accelerates proliferation of these cells. These findings suggest the early presence of humoral factors following traumatic brain injury that stimulate the expansion of mesenchymal cells and osteoprogenitors within skeletal muscle.

  17. Assessment of the paraspinal muscles of subjects presenting an idiopathic scoliosis: an EMG pilot study

    Directory of Open Access Journals (Sweden)

    Larivière Christian

    2005-03-01

    Full Text Available Abstract Background It is known that the back muscles of scoliotic subjects present abnormalities in their fiber type composition. Some researchers have hypothesized that abnormal fiber composition can lead to paraspinal muscle dysfunction such as poor neuromuscular efficiency and muscle fatigue. EMG parameters were used to evaluate these impairments. The purpose of the present study was to examine the clinical potential of different EMG parameters such as amplitude (RMS and median frequency (MF of the power spectrum in order to assess the back muscles of patients presenting idiopathic scoliosis in terms of their neuromuscular efficiency and their muscular fatigue. Methods L5/S1 moments during isometric efforts in extension were measured in six subjects with idiopathic scoliosis and ten healthy controls. The subjects performed three 7 s ramp contractions ranging from 0 to 100% maximum voluntary contraction (MVC and one 30 s sustained contraction at 75% MVC. Surface EMG activity was recorded bilaterally from the paraspinal muscles at L5, L3, L1 and T10. The slope of the EMG RMS/force (neuromuscular efficiency and MF/force (muscle composition relationships were computed during the ramp contractions while the slope of the EMG RMS/time and MF/time relationships (muscle fatigue were computed during the sustained contraction. Comparisons were performed between the two groups and between the left and right sides for the EMG parameters. Results No significant group or side differences between the slopes of the different measures used were found at the level of the apex (around T10 of the major curve of the spine. However, a significant side difference was seen at a lower level (L3, p = 0.01 for the MF/time parameter. Conclusion The EMG parameters used in this study could not discriminate between the back muscles of scoliotic subjects and those of control subject regarding fiber type composition, neuromuscular efficiency and muscle fatigue at the level

  18. The effects of Kinesio taping on muscle tone in healthy subjects: a double-blind, placebo-controlled crossover trial.

    Science.gov (United States)

    Gómez-Soriano, Julio; Abián-Vicén, Javier; Aparicio-García, Carlos; Ruiz-Lázaro, Pilar; Simón-Martínez, Cristina; Bravo-Esteban, Elisabeth; Fernández-Rodríguez, José Manuel

    2014-04-01

    Kinesio taping (KT) has been proposed to modulate muscle tone. However no studies have systematically studied the efficacy of KTon this primary outcome measure. The objective of this study was to determine the effect of Kinesio taping (KT) applied over the gastrocnemius muscles on muscle tone, extensibility, electromyography (EMG) and strength. Nineteen healthy subjects were enrolled in a double-blind, placebo controlled crossover trial. KT and sham-tape were applied onto the gastrocnemius muscles of all subjects in two randomized sessions. Measurements before, at 10 min and 24 h after the intervention were taken. Outcome measurements included passive resistive torque to ankle dorsiflexion, dorsiflexion passive range of motion (PROM), surface Gastrocnemius Medialis (GM) EMG and maximal isometric voluntary force (MIVF). No significant differences were found between the sham-tape and KT groups for passive resistive torque, PROM nor maximal plantarflexion isometric voluntary force. A short-term increase of GM EMG activity was found in the KT group during the PROM mobilization, which was not maintained at 24 h following treatment. A short-term decrease in dorsiflexion force was produced 10 min after KT with respect to sham-tape application. These results demonstrate that the application of KT in the gastrocnemius muscles has no effect on healthy muscle tone, extensibility nor strength. However a short-term increase of GM EMG activity after KT treatment suggests the activation of central nervous system mechanisms, although without a therapeutic implication. Further studies with more appropriate designs are needed to clarify the physiological and therapeutic effects of this taping technique.

  19. GH signaling in skeletal muscle and adipose tissue in healthy human subjects

    DEFF Research Database (Denmark)

    Vestergaard, Poul F; Vendelbo, Mikkel H; Pedersen, Steen B

    2014-01-01

    RNA response (r=0.533, P=0.05). CONCLUSION: i) GH signaling in muscle and fat after a single GH bolus in healthy human subjects is age independent, ii) we hypothesize that constitutive overexpression of CISH may contribute to the relative GH resistance in women, and iii) experimental studies on the impact...... of sex steroid administration and physical training on GH signaling in human subjects in vivo are required....

  20. Co-activation of upper limb muscles during reaching in post-stroke subjects: an analysis of the contralesional and ipsilesional limbs.

    Science.gov (United States)

    Silva, Cláudia C; Silva, Augusta; Sousa, Andreia; Pinheiro, Ana Rita; Bourlinova, Catarina; Silva, Ana; Salazar, António; Borges, Carla; Crasto, Carlos; Correia, Miguel Velhote; Vilas-Boas, João Paulo; Santos, Rubim

    2014-10-01

    The purpose of this study was to analyze the change in antagonist co-activation ratio of upper-limb muscle pairs, during the reaching movement, of both ipsilesional and contralesional limbs of post-stroke subjects. Nine healthy and nine post-stroke subjects were instructed to reach and grasp a target, placed in the sagittal and scapular planes of movement. Surface EMG was recorded from postural control and movement related muscles. Reaching movement was divided in two sub-phases, according to proximal postural control versus movement control demands, during which antagonist co-activation ratios were calculated for the muscle pairs LD/PM, PD/AD, TRIlat/BB and TRIlat/BR. Post-stroke's ipsilesional limb presented lower co-activation in muscles with an important role in postural control (LD/PM), comparing to the healthy subjects during the first sub-phase, when the movement was performed in the sagittal plane (plimb showed in general an increased co-activation ratio in muscles related to movement control, comparing to the healthy subjects. Our findings demonstrate that, in post-stroke subjects, the reaching movement performed with the ipsilesional upper limb seems to show co-activation impairments in muscle pairs associated to postural control, whereas the contralesional upper limb seems to have signs of impairment of muscle pairs related to movement. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Clenbuterol increases lean muscle mass but not endurance in patients with chronic heart failure.

    Science.gov (United States)

    Kamalakkannan, Gayathri; Petrilli, Christopher M; George, Isaac; LaManca, John; McLaughlin, Brooke T; Shane, Elizabeth; Mancini, Donna M; Maybaum, Simon

    2008-04-01

    Clenbuterol, a beta(2)-agonist with potent anabolic properties, has been shown to improve skeletal muscle function in healthy subjects, and in high doses, promotes cardiac recovery in patients with left ventricular assist devices. In a small, randomized controlled study, we investigated the effect of clenbuterol on skeletal muscle function, cardiac function, and exercise capacity in patients with chronic heart failure. Clenbuterol was well tolerated and led to a significant increase in both lean mass and the lean/fat ratio. Maximal strength increased significantly with both clenbuterol (27%) and placebo (14%); however, endurance and exercise duration decreased after clenbuterol. Prior data support combining exercise training with clenbuterol to maximize performance, and on-going studies will evaluate this approach.

  2. Is Walking Capacity in Subjects with Multiple Sclerosis Primarily Related to Muscle Oxidative Capacity or Maximal Muscle Strength? A Pilot Study

    Directory of Open Access Journals (Sweden)

    Dominique Hansen

    2014-01-01

    Full Text Available Background and Purpose. Walking capacity is reduced in subjects with multiple sclerosis (MS. To develop effective exercise interventions to enhance walking capacity, it is important to determine the impact of factors, modifiable by exercise intervention (maximal muscle strength versus muscle oxidative capacity, on walking capacity. The purpose of this pilot study is to discriminate between the impact of maximal muscle strength versus muscle oxidative capacity on walking capacity in subjects with MS. Methods. From 24 patients with MS, muscle oxidative capacity was determined by calculation of exercise-onset oxygen uptake kinetics (mean response time during submaximal exercise bouts. Maximal muscle strength (isometric knee extension and flexion peak torque was assessed on dynamometer. All subjects completed a 6-minute walking test. Relationships between walking capacity (as a percentage of normal value and muscle strength (of knee flexors and extensors versus muscle oxidative capacity were assessed in multivariate regression analyses. Results. The expanded disability status score (EDSS showed a significant univariate correlation (r=-0.70, P<0.004 with walking capacity. In multivariate regression analyses, EDSS and mean response time, but not muscle strength, were independently related to walking capacity (P<0.05. Conclusions. Walking distance is, next to disability level and not taking neurologic symptoms/deficits into account, primarily related to muscle oxidative capacity in subjects with MS. Additional study is needed to further examine/verify these findings.

  3. Methods for increasing upper airway muscle tonus in treating obstructive sleep apnea: systematic review.

    Science.gov (United States)

    Valbuza, Juliana Spelta; de Oliveira, Márcio Moysés; Conti, Cristiane Fiquene; Prado, Lucila Bizari F; de Carvalho, Luciane Bizari Coin; do Prado, Gilmar Fernandes

    2010-12-01

    Treatment of obstructive sleep apnea (OSA) using methods for increasing upper airway muscle tonus has been controversial and poorly reported. Thus, a review of the evidence is needed to evaluate the effectiveness of these methods. The design used was a systematic review of randomized controlled trials. Data sources are from the Cochrane Library, Medline, Embase and Scielo, registries of ongoing trials, theses indexed at Biblioteca Regional de Medicina/Pan-American Health Organization of the World Health Organization and the reference lists of all the trials retrieved. This was a review of randomized or quasi-randomized double-blind trials on OSA. Two reviewers independently applied eligibility criteria. One reviewer assessed study quality and extracted data, and these processes were checked by a second reviewer. The primary outcome was a decrease in the apnea/hypopnea index (AHI) of below five episodes per hour. Other outcomes were subjective sleep quality, sleep quality measured by night polysomnography, quality of life measured subjectively and adverse events associated with the treatments. Three eligible trials were included. Two studies showed improvements through the objective and subjective analyses, and one study showed improvement of snoring, but not of AHI while the subjective analyses showed no improvement. The adverse events were reported and they were not significant. There is no accepted scientific evidence that methods aiming to increase muscle tonus of the stomatognathic system are effective in reducing AHI to below five events per hour. Well-designed randomized controlled trials are needed to assess the efficacy of such methods.

  4. Weight loss may be a better approach for managing musculoskeletal conditions than increasing muscle mass and strength.

    Science.gov (United States)

    Kim, Bokun; Tsujimoto, Takehiko; So, Rina; Zhao, Xiaoguang; Suzuki, Shun; Kim, Taeho; Tanaka, Kiyoji

    2015-12-01

    To prevent or remedy musculoskeletal conditions, the relationship between obesity and the characteristics of muscle mass and strength need to be clarified. [Subjects and Methods] A total of 259 Japanese males aged 30-64 years were classified into 4 groups according to the Japanese obesity criteria. Body composition was evaluated, and handgrip strength and knee extensor strength were measured for the upper and lower extremities, respectively. Physical performance was evaluated with a jump test. [Results] Obesity was positively correlated with skeletal muscle mass index, percentage of whole-body fat, and leg muscle strength and negatively correlated with the percentage of muscle mass index, body weight-normalized handgrip strength, and knee extensor strength, and the jump test results. [Conclusion] Weight loss may be a better approach than increasing muscle mass and strength to improve musculoskeletal conditions in obese adult males.

  5. Essential amino acids and exercise tolerance in elderly muscle-depleted subjects with chronic diseases: a rehabilitation without rehabilitation?

    Science.gov (United States)

    Aquilani, Roberto; D'Antona, Giuseppe; Baiardi, Paola; Gambino, Arianna; Iadarola, Paolo; Viglio, Simona; Pasini, Evasio; Verri, Manuela; Barbieri, Annalisa; Boschi, Federica

    2014-01-01

    Exercise intolerance remains problematic in subjects with chronic heart failure (CHF) and/or chronic obstructive pulmonary disease (COPD). Recent studies show that supplemented essential amino acids (EAAs) may exert beneficial effects on CHF/COPD physical capacity. The results from 3 investigations (2 conducted on CHF and 1 on COPD subjects) served as the basis for this paper. The 3 studies consistently showed that elderly CHF and COPD improved exercise intolerance after 1-3 months of EAA supplementation (8 g/d). In CHF exercise capacity increased 18.7% to 23% (watts; bicycle test), and 12% to 22% (meters) in 6 min walking test. Moreover, patients reduced their resting plasma lactate levels (by 25%) and improved tissue insulin sensitivity by 16% (HOMA index). COPD subjects enjoyed similar benefits as CHF ones. They increased physical autonomy by 78.6% steps/day and decreased resting plasma lactate concentrations by 23%. EAA mechanisms explaining improved exercise intolerance could be increases in muscle aerobic metabolism, mass and function, and improvement of tissue insulin sensitivity (the latter only for the CHF population). These mechanisms could be accounted for by EAA's intrinsic physiological activity which increases myofibrils and mitochondria genesis in skeletal muscle and myocardium and glucose control. Supplemented EAAs can improve the physical autonomy of subjects with CHF/COPD.

  6. Essential Amino Acids and Exercise Tolerance in Elderly Muscle-Depleted Subjects with Chronic Diseases: A Rehabilitation without Rehabilitation?

    Directory of Open Access Journals (Sweden)

    Roberto Aquilani

    2014-01-01

    Full Text Available Exercise intolerance remains problematic in subjects with chronic heart failure (CHF and/or chronic obstructive pulmonary disease (COPD. Recent studies show that supplemented essential amino acids (EAAs may exert beneficial effects on CHF/COPD physical capacity. The results from 3 investigations (2 conducted on CHF and 1 on COPD subjects served as the basis for this paper. The 3 studies consistently showed that elderly CHF and COPD improved exercise intolerance after 1–3 months of EAA supplementation (8 g/d. In CHF exercise capacity increased 18.7% to 23% (watts; bicycle test, and 12% to 22% (meters in 6 min walking test. Moreover, patients reduced their resting plasma lactate levels (by 25% and improved tissue insulin sensitivity by 16% (HOMA index. COPD subjects enjoyed similar benefits as CHF ones. They increased physical autonomy by 78.6% steps/day and decreased resting plasma lactate concentrations by 23%. EAA mechanisms explaining improved exercise intolerance could be increases in muscle aerobic metabolism, mass and function, and improvement of tissue insulin sensitivity (the latter only for the CHF population. These mechanisms could be accounted for by EAA’s intrinsic physiological activity which increases myofibrils and mitochondria genesis in skeletal muscle and myocardium and glucose control. Supplemented EAAs can improve the physical autonomy of subjects with CHF/COPD.

  7. Intra-subject variability in muscle activity and co-contraction during jumps and landings in children and adults

    DEFF Research Database (Denmark)

    Raffalt, P C; Alkjaer, T; Simonsen, E B

    2017-01-01

    and 60 cm for the children and 60 and 90 cm for the adults. The adults also performed ten DJ from 60 cm. EMG was recorded from nine lower limb muscles in the right leg and normalized to isometric MVC. Statistical parametric mapping was used to reveal differences in the muscle activity and intra......We investigated muscle activity, intra-subject variability in muscle activity and co-contraction during vertical jumps and landings in children and adults. Ten male children and 10 male adults completed 10 countermovement jumps (CMJ), 10 drop jumps (DJ) from 30 cm, 10 low and high landings from 30......-subject variability in the muscle activity. Co-contraction was quantified for two thigh muscle pairs and one plantar flexor/dorsiflexor muscle pair and group differences were assessed (two-way ANOVA). No significant differences were observed in the less eccentric demanding CMJ while significantly higher muscle...

  8. Muscle Fatigue Increases the Probability of Developing Hyperalgesia in Mice

    OpenAIRE

    Yokoyama, Takeshi; Lisi, Tammy L.; Moore, Steven A.; Sluka, Kathleen A.

    2007-01-01

    Chronic muscle pain is a major clinical problem that is often associated with fatigue. Conversely, chronic fatigue conditions are commonly associated with muscle pain. We tested the hypothesis that muscle fatigue enhances hyperalgesia associated with injection of acidic saline into muscle. We evaluated mechanical sensitivity of the paw (von Frey) in mice after 2 intramuscular injections of saline (20 µL; pH 4, pH 5, pH 6, pH 7.2) in a fatigue and a control group. To induce fatigue, mice were ...

  9. Comparison of hamstring muscle behavior for anterior cruciate ligament (ACL) patient and normal subject during local marching

    Science.gov (United States)

    Amineldin@Aminudin, Nurul Izzaty Bt.; Rambely, A. S.

    2014-09-01

    This study aims to investigate the hamstring muscle activity after the surgery by carrying out an electromyography experiment on the hamstring and to compare the behavior of the ACL muscle activity between ACL patient and control subject. Electromyography (EMG) is used to study the behavior of muscles during walking activity. Two hamstring muscles involved which are semitendinosus and bicep femoris. The EMG data for both muscles were recorded while the subject did maximum voluntary contraction (MVC) and marching. The study concluded that there were similarities between bicep femoris of the ACL and control subjects. The analysis showed that the biceps femoris muscle of the ACL subject had no abnormality and the pattern is as normal as the control subject. However, ACL patient has poor semitendinosus muscle strength compared to that of control subject because the differences of the forces produced. The force of semitendinosus value for control subject was two times greater than that of the ACL subject as the right semitendinosus muscle of ACL subject was used to replace the anterior cruciate ligament (ACL) that was injured.

  10. Probiotic Bacillus coagulans GBI-30, 6086 reduces exercise-induced muscle damage and increases recovery

    Directory of Open Access Journals (Sweden)

    Ralf Jäger

    2016-07-01

    Full Text Available Objective. Probiotics have been reported to support healthy digestive and immune function, aid in protein absorption, and decrease inflammation. Further, a trend to increase vertical jump power has been observed following co-administration of protein and probiotics in resistance-trained subjects. However, to date the potential beneficial effect of probiotics on recovery from high intensity resistance exercise have yet to be explored. Therefore, this study examined the effect of co-administration of protein and probiotics on muscle damage, recovery and performance following a damaging exercise bout. Design. Twenty nine (n = 29 recreationally-trained males (mean ± SD; 21.5 ± 2.8 years; 89.7 ± 28.2 kg; 177.4 ± 8.0 cm were assigned to consume either 20 g of casein (PRO or 20 g of casein plus probiotic (1 billion CFU Bacillus coagulans GBI-30, 6086, PROBC in a crossover, diet-controlled design. After two weeks of supplementation, perceptional measures, athletic performance, and muscle damage were analyzed following a damaging exercise bout. Results. The damaging exercise bout significantly increased muscle soreness, and reduced perceived recovery; however, PROBC significantly increased recovery at 24 and 72 h, and decreased soreness at 72 h post exercise in comparison to PRO. Perceptual measures were confirmed by increases in CK (PRO: +266.8%, p = 0.0002; PROBC: +137.7%, p = 0.01, with PROBC showing a trend towards reduced muscle damage (p = 0.08. The muscle-damaging exercise resulted in significantly increased muscle swelling and Blood Urea Nitrogen levels in both conditions with no difference between groups. The strenuous exercise significantly reduced athletic performance in PRO (Wingate Peak Power; PRO: (−39.8 watts, −5.3%, p = 0.03, whereas PROBC maintained performance (+10.1 watts, +1.7%. Conclusions. The results provide evidence that probiotic supplementation in combination with protein tended to reduce indices of muscle damage

  11. Relationship between increased carotid artery stiffness and idiopathic subjective tinnitus.

    Science.gov (United States)

    Bayraktar, C; Taşolar, S

    2017-05-01

    Tinnitus is defined as perception of sound with no external stimulus, and can separate into pulsatile and non-pulsatile types. Arterial stiffness is a parameter that can predict the cardiovascular event and associated with incidence of stroke. It has been shown that increased arterial stiffness may lead to microvascular damage in brain. Our aim was to assess the arterial stiffness of the carotid system in the development and severity of idiopathic subjective tinnitus. Forty subjective tinnitus patients and 40 age- and sex-matched controls were enrolled in the study. The parameters obtained from the participants included pure tone hearing (dB), serum lipid profile (mg/dl), fasting glucose (mg/dl), blood pressure (mmHg), and body mass index (BMI, kg/m2). The common carotid artery (CCA) stiffness index, Young's elastic modulus (YEM), common carotid intima-media thickness (CIMT), peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index (RI), pulsatility index (PI), vessel diameter, mean velocity (MV), and volume flow (VF) were measured in both the right and left common carotid arteries in both groups. The CCA stiffness index, YEM measurements, right CIMT, and left PI were found to be significantly higher in the patients than those in the control group (p tinnitus and the patient characteristics, there was a significant positive correlation with the CCA stiffness index, YEM measurements, left CIMT, and neutrophil-to-lymphocyte ratio (NLR). However, only the right and left CCA stiffness parameters were found to be statistically significant in the multivariate analysis as independent predictors of a moderate to high degree of tinnitus. The increased stiffness index of the common carotid arteries was significantly associated with the formation and severity of tinnitus. Therefore, an assessment of the carotideal system may be helpful in these patients.

  12. Calorie restriction increases muscle mitochondrial biogenesis in healthy humans.

    Directory of Open Access Journals (Sweden)

    Anthony E Civitarese

    2007-03-01

    Full Text Available Caloric restriction without malnutrition extends life span in a range of organisms including insects and mammals and lowers free radical production by the mitochondria. However, the mechanism responsible for this adaptation are poorly understood.The current study was undertaken to examine muscle mitochondrial bioenergetics in response to caloric restriction alone or in combination with exercise in 36 young (36.8 +/- 1.0 y, overweight (body mass index, 27.8 +/- 0.7 kg/m(2 individuals randomized into one of three groups for a 6-mo intervention: Control, 100% of energy requirements; CR, 25% caloric restriction; and CREX, caloric restriction with exercise (CREX, 12.5% CR + 12.5% increased energy expenditure (EE. In the controls, 24-h EE was unchanged, but in CR and CREX it was significantly reduced from baseline even after adjustment for the loss of metabolic mass (CR, -135 +/- 42 kcal/d, p = 0.002 and CREX, -117 +/- 52 kcal/d, p = 0.008. Participants in the CR and CREX groups had increased expression of genes encoding proteins involved in mitochondrial function such as PPARGC1A, TFAM, eNOS, SIRT1, and PARL (all, p < 0.05. In parallel, mitochondrial DNA content increased by 35% +/- 5% in the CR group (p = 0.005 and 21% +/- 4% in the CREX group (p < 0.004, with no change in the control group (2% +/- 2%. However, the activity of key mitochondrial enzymes of the TCA (tricarboxylic acid cycle (citrate synthase, beta-oxidation (beta-hydroxyacyl-CoA dehydrogenase, and electron transport chain (cytochrome C oxidase II was unchanged. DNA damage was reduced from baseline in the CR (-0.56 +/- 0.11 arbitrary units, p = 0.003 and CREX (-0.45 +/- 0.12 arbitrary units, p = 0.011, but not in the controls. In primary cultures of human myotubes, a nitric oxide donor (mimicking eNOS signaling induced mitochondrial biogenesis but failed to induce SIRT1 protein expression, suggesting that additional factors may regulate SIRT1 content during CR.The observed increase in

  13. Reproducibility and responsiveness of a noninvasive EMG technique of the respiratory muscles in COPD patients and in healthy subjects

    NARCIS (Netherlands)

    Duiverman, ML; van Eykern, LA; Vennik, PW; Koeter, GH; Maarsingh, EJW; Wijkstra, PJ

    2004-01-01

    In the present study, we assessed the reproducibility and responsiveness of transcutaneous electromyography (EMG) of the respiratory muscles in patients with chronic obstructive pulmonary disease ( COPD) and healthy subjects during breathing against an inspiratory load. In seven healthy subjects and

  14. Does wearing a functional knee brace affect hamstring reflex time in subjects with anterior cruciate ligament deficiency during muscle fatigue?

    Science.gov (United States)

    Lam, Rita Y; Ng, Gabriel Y; Chien, Eric P

    2002-07-01

    To evaluate the effects of wearing a functional knee brace and muscle fatigue on hamstring reflex time in subjects with anterior cruciate ligament (ACL) deficiency. Repeated-measures clinical trial. Outpatient physical therapy department. Sixteen subjects with ACL deficiency. Subjects tested with and without a functional knee brace before and after an exercise protocol designed to fatigue the knee muscles. Latency of hamstring reflex muscle activity after sudden perturbation of the knee. Wearing a knee brace shortened the hamstring reflex latency regardless of fatigue (F(1,15)=20.62, Pknee brace facilitated hamstring muscle reflex, but muscle fatigue lengthened the hamstring reflex latency. Subjects with ACL deficiency should not rely on the knee brace to facilitate hamstring reflex for joint protection during prolonged sporting activities when muscles are fatigued. Copyright 2002 by the American Congress of Rehabilitation Medicine and the American Academy of physical Medicine and Rehabilitation

  15. Overexpression of Striated Muscle Activator of Rho Signaling (STARS) Increases C2C12 Skeletal Muscle Cell Differentiation.

    Science.gov (United States)

    Wallace, Marita A; Della Gatta, Paul A; Ahmad Mir, Bilal; Kowalski, Greg M; Kloehn, Joachim; McConville, Malcom J; Russell, Aaron P; Lamon, Séverine

    2016-01-01

    Skeletal muscle growth and regeneration depend on the activation of satellite cells, which leads to myocyte proliferation, differentiation and fusion with existing muscle fibers. Skeletal muscle cell proliferation and differentiation are tightly coordinated by a continuum of molecular signaling pathways. The striated muscle activator of Rho signaling (STARS) is an actin binding protein that regulates the transcription of genes involved in muscle cell growth, structure and function via the stimulation of actin polymerization and activation of serum-response factor (SRF) signaling. STARS mediates cell proliferation in smooth and cardiac muscle models; however, whether STARS overexpression enhances cell proliferation and differentiation has not been investigated in skeletal muscle cells. We demonstrate for the first time that STARS overexpression enhances differentiation but not proliferation in C2C12 mouse skeletal muscle cells. Increased differentiation was associated with an increase in the gene levels of the myogenic differentiation markers Ckm, Ckmt2 and Myh4, the differentiation factor Igf2 and the myogenic regulatory factors (MRFs) Myf5 and Myf6. Exposing C2C12 cells to CCG-1423, a pharmacological inhibitor of SRF preventing the nuclear translocation of its co-factor MRTF-A, had no effect on myotube differentiation rate, suggesting that STARS regulates differentiation via a MRTF-A independent mechanism. These findings position STARS as an important regulator of skeletal muscle growth and regeneration.

  16. Effects of progressive muscle relaxation on state anxiety and subjective well-being in people with schizophrenia: a randomized controlled trial.

    Science.gov (United States)

    Vancampfort, Davy; De Hert, Marc; Knapen, Jan; Maurissen, Katrien; Raepsaet, Julie; Deckx, Seppe; Remans, Sander; Probst, Michel

    2011-06-01

    To examine the efficacy of a single progressive muscle relaxation session compared with a control condition on state anxiety, psychological stress, fatigue and subjective well-being in patients with schizophrenia. Randomized controlled trial. An acute inpatient care unit of an University Psychiatric Centre. Sixty-four out of 88 eligible patients with schizophrenia. Patients were randomly assigned to either a single progressive muscle relaxation session during 25 minutes or a resting control condition with the opportunity to read for an equal amount of time. Before and after the single interventions the State anxiety inventory and the Subjective exercise experiences scale were completed. Effect sizes were calculated. Only within progressive muscle relaxation, participants (n=27) showed decreased state anxiety, psychological stress and fatigue and increased subjective well-being. Between-group differences in post scores were found for state anxiety, subjective well-being and psychological stress, but not for fatigue. The effect size favouring progressive muscle relaxation was 1.26 for subjective well-being and -1.25 and -1.02 for respectively state anxiety and psychological stress. Progressive muscle relaxation is highly effective in reducing acute feelings of stress and anxiety in patients with schizophrenia. A reduction in stress and state anxiety is associated with an increase in subjective well-being.

  17. Training-induced changes in muscle CSA, muscle strength, EMG, and rate of force development in elderly subjects after long-term unilateral disuse

    DEFF Research Database (Denmark)

    Suetta, Charlotte; Aagaard, Per; Rosted, Anna

    2004-01-01

    The ability to develop muscle force rapidly may be a very important factor to prevent a fall and to perform other tasks of daily life. However, information is still lacking on the range of training-induced neuromuscular adaptations in elderly humans recovering from a period of disuse. Therefore......, the present study examined the effect of three types of training regimes after unilateral prolonged disuse and subsequent hip-replacement surgery on maximal muscle strength, rapid muscle force [rate of force development (RFD)], muscle activation, and muscle size. Thirty-six subjects (60-86 yr) were randomized...... to a 12-wk rehabilitation program consisting of either 1) strength training (3 times/wk for 12 wk), 2) electrical muscle stimulation (1 h/day for 12 wk), or 3) standard rehabilitation (1 h/day for 12 wk). The nonoperated side did not receive any intervention and thereby served as a within-subject control...

  18. Neuromuscular control of scapula muscles during a voluntary task in subjects with Subacromial Impingement Syndrome

    DEFF Research Database (Denmark)

    Larsen, C M; Søgaard, Karen; Chreiteh, S S

    2013-01-01

    Imbalance of neuromuscular activity in the scapula stabilizers in subjects with Subacromial Impingement Syndrome (SIS) is described in restricted tasks and specific populations. Our aim was to compare the scapular muscle activity during a voluntary movement task in a general population with and w......Imbalance of neuromuscular activity in the scapula stabilizers in subjects with Subacromial Impingement Syndrome (SIS) is described in restricted tasks and specific populations. Our aim was to compare the scapular muscle activity during a voluntary movement task in a general population...... with and without SIS (n=16, No-SIS=15). Surface electromyography was measured from Serratus anterior (SA) and Trapezius during bilateral arm elevation (no-load, 1kg, 3kg). Mean relative muscle activity was calculated for SA and the upper (UT) and lower part of trapezius (LWT), in addition to activation ratio...... and time to activity onset. In spite of a tendency to higher activity among SIS 0.10-0.30 between-group differences were not significant neither in ratio of muscle activation 0.80-0.98 nor time to activity onset 0.53-0.98. The hypothesized between-group differences in neuromuscular activity of Trapezius...

  19. The Prevalence of Latent Trigger Points in Lower Limb Muscles in Asymptomatic Subjects.

    Science.gov (United States)

    Zuil-Escobar, Juan Carlos; Martínez-Cepa, Carmen Belén; Martín-Urrialde, Jose Antonio; Gómez-Conesa, Antonia

    2016-11-01

    Latent trigger points (LTrPs) are prevalent in persons with musculoskeletal pain. Because they could be present in healthy persons, it is necessary to evaluate the prevalence of LTrPs in asymptomatic subjects. To assess the prevalence of LTrPs in lower limb muscles, to evaluate the relationship between LTrP prevalence, gender, and leg dominance, and to determine intra-rater reliability for the diagnosis of LTrPs. Cross-sectional study. University community. A total of 206 asymptomatic subjects (113 women and 93 men, aged 23.2 ± 5.2 years). Not applicable. The prevalence of the LTrPs located in the gastrocnemius, soleus, peroneus longus, peroneus brevis, tibialis anterior, extensor digitorum longus, flexor digitorum longus, rectus femoris, vastus medialis, and vastus lateralis was studied, using the diagnosis criteria recommended by Simons, Travell, and Simons. The pressure pain threshold was also evaluated. Of the 206 subjects evaluated, 166 (77.7%; 95% confidence interval [CI], 72-83.4) were found to have at least one LTrP in the lower limb muscles. The average number of LTrPs found per individual was 7.5 ± 7.7. The prevalence in each muscle group ranged from 19.9% (95% CI, 14.4-25.4) to 37.4% (95% CI, 30.8-44), with gastrocnemius LTrPs being the most prevalent. Women had more LTrPs (9.6 ± 7.8) than did men (4.9 ± 6.6) (P .05). The most prevalent diagnosis criteria were the presence of a taut band and a tender spot (98%-100%); the local twitch response was the least prevalent diagnosis criteria (0%-3.5%). Intra-rater reliability was excellent for all the diagnosis criteria in all the muscles evaluated (κ = 0.762-1), except for the jump sign and the referred pain in several LTrPs. LTrPs were prevalent in the lower limb muscles of asymptomatic subjects. Women have more LTrPs than do men. No differences in LTrP prevalence were found between sides. The presence of the taut band and the tender spot were the most prevalent and reliable diagnosis criteria. It is

  20. Occlusal force, electromyographic activity of masticatory muscles and mandibular flexure of subjects with different facial types.

    Science.gov (United States)

    Custodio, William; Gomes, Simone Guimarães Farias; Faot, Fernanda; Garcia, Renata Cunha Matheus Rodrigues; Del Bel Cury, Altair Antoninha

    2011-08-01

    The aim of this study was to evaluate whether vertical facial patterns influence maximal occlusal force (MOF), masticatory muscle electromyographic (EMG) activity, and medial mandibular flexure (MMF). Seventy-eight dentate subjects were divided into 3 groups by Ricketts's analysis: brachyfacial, mesofacial and dolychofacial. Maximum occlusal force in the molar region was bilaterally measured with a force transducer. The electromyographic activities of the masseter and anterior temporal muscles were recorded during maximal voluntary clenching. Medial mandibular flexure was calculated by subtracting the intermolar distance of maximum opening or protrusion from the distance in the rest position. The data were analyzed using ANOVA followed by Tukey's HSD test. The significance level was set at 5%. Data on maximum occlusal force showed that shorter faces had higher occlusal forces (Pmandibular flexure, followed by the mesofacial and dolychofacial groups. Additionally, dolychofacial subjects showed significantly lower electromyographic temporalis activities (Pmandibular flexure were influenced by the vertical facial pattern.

  1. Abnormal epigenetic changes during differentiation of human skeletal muscle stem cells from obese subjects

    DEFF Research Database (Denmark)

    Davegårdh, Cajsa; Broholm, Christa; Perfilyev, Alexander

    2017-01-01

    subjects. Interestingly, numerous genes implicated in metabolic diseases and epigenetic regulation showed differential methylation and expression during differentiation only in obese subjects. CONCLUSIONS: Our study identifies IL-32 as a novel myogenic regulator, provides a comprehensive map of the dynamic...... is associated with low relative muscle mass and diminished metabolism. Epigenetic alterations taking place during myogenesis might contribute to these defects. METHODS: We used Infinium HumanMethylation450 BeadChip Kit (Illumina) and HumanHT-12 Expression BeadChip (Illumina) to analyze genome-wide DNA......-wide changes in DNA methylation and expression patterns during differentiation of primary human muscle stem cells (myoblasts). We identified epigenetic and transcriptional changes of myogenic transcription factors (MYOD1, MYOG, MYF5, MYF6, PAX7, MEF2A, MEF2C, and MEF2D), cell cycle regulators, metabolic...

  2. NF-κB activity in muscle from obese and type 2 diabetic subjects under basal and exercise-stimulated conditions.

    Science.gov (United States)

    Tantiwong, Puntip; Shanmugasundaram, Karthigayan; Monroy, Adriana; Ghosh, Sangeeta; Li, Mengyao; DeFronzo, Ralph A; Cersosimo, Eugenio; Sriwijitkamol, Apiradee; Mohan, Sumathy; Musi, Nicolas

    2010-11-01

    NF-κB is a transcription factor that controls the gene expression of several proinflammatory proteins. Cell culture and animal studies have implicated increased NF-κB activity in the pathogenesis of insulin resistance and muscle atrophy. However, it is unclear whether insulin-resistant human subjects have abnormal NF-κB activity in muscle. The effect that exercise has on NF-κB activity/signaling also is not clear. We measured NF-κB DNA-binding activity and the mRNA level of putative NF-κB-regulated myokines interleukin (IL)-6 and monocyte chemotactic protein-1 (MCP-1) in muscle samples from T2DM, obese, and lean subjects immediately before, during (40 min), and after (210 min) a bout of moderate-intensity cycle exercise. At baseline, NF-κB activity was elevated 2.1- and 2.7-fold in obese nondiabetic and T2DM subjects, respectively. NF-κB activity was increased significantly at 210 min following exercise in lean (1.9-fold) and obese (2.6-fold) subjects, but NF-κB activity did not change in T2DM. Exercise increased MCP-1 mRNA levels significantly in the three groups, whereas IL-6 gene expression increased significantly only in lean and obese subjects. MCP-1 and IL-6 gene expression peaked at the 40-min exercise time point. We conclude that insulin-resistant subjects have increased basal NF-κB activity in muscle. Acute exercise stimulates NF-κB in muscle from nondiabetic subjects. In T2DM subjects, exercise had no effect on NF-κB activity, which could be explained by the already elevated NF-κB activity at baseline. Exercise-induced MCP-1 and IL-6 gene expression precedes increases in NF-κB activity, suggesting that other factors promote gene expression of these cytokines during exercise.

  3. Increased proportion of megafibers in chronically painful muscles

    DEFF Research Database (Denmark)

    Andersen, Lars L; Suetta, Charlotte; Andersen, Jesper Løvind

    2008-01-01

    . The percentage of megafibers was positively related to age and weekly working hours, indicating an effect of long-term exposure. In conclusion, this study shows that trapezius myalgia is associated with a significantly higher percentage of grossly hypertrophied type I muscle fibers with poor capillarization......Trapezius myalgia - chronic pain from the upper trapezius muscle - is frequent in female employees in monotonous stressful jobs, potentially due to chronic overload of type I muscle fibers. In this study, we investigated the intra-individual distribution of trapezius muscle fiber size......, and hypothesized that females with myalgia compared with matched healthy controls have a higher percentage of grossly hypertrophied type I fibers with poor capillarization. Forty-two female office workers with trapezius myalgia (MYA) and 20 healthy matched controls (CON) participated in the study. Standard...

  4. Functional connectivity between core and shoulder muscles increases during isometric endurance contractions in judo competitors

    DEFF Research Database (Denmark)

    Kawczyński, Adam; Samani, Afshin; Mroczek, Dariusz

    2015-01-01

    Purpose: The aim of this study was to assess the surface electromyogram (SEMG) changes within and between muscles of the torso and shoulder region during static endurance contraction in elite judokas. We hypothesized an increased functional connectivity of muscles from the shoulder and torso...... : We concluded that the increases in NMIs highlighted functional changes in the interplay between core and shoulder muscles during an endurance contraction in elite judokas....... endurance contraction consisting of bilateral arm abduction at 90°. The normalized mutual information (NMI) was computed between muscle pairs as an index indicating functional connectivity. Results: The NMIs increased significantly during endurance test for 10 of the 15 muscle pairs (P

  5. Skeletal muscle insulin resistance promotes increased hepatic de novo lipogenesis, hyperlipidemia, and hepatic steatosis in the elderly.

    Science.gov (United States)

    Flannery, Clare; Dufour, Sylvie; Rabøl, Rasmus; Shulman, Gerald I; Petersen, Kitt Falk

    2012-11-01

    Aging is closely associated with muscle insulin resistance, hyperlipidemia, nonalcoholic fatty liver disease (NAFLD), and type 2 diabetes. We examined the hypothesis that muscle insulin resistance in healthy aging promotes increased hepatic de novo lipogenesis (DNL) and hyperlipidemia by altering the distribution pattern of postprandial energy storage. Healthy, normal weight, sedentary elderly subjects pair-matched to young subjects were given two high-carbohydrate meals followed by ¹³C/¹H magnetic resonance spectroscopy measurements of postprandial changes in muscle and liver glycogen and lipid content, and assessment of DNL using ²H₂O. Net muscle glycogen synthesis was reduced by 45% (P < 0.007) in the elderly subjects compared with the young, reflecting severe muscle insulin resistance. Net liver glycogen synthesis was similar between groups (elderly, 143 ± 23 mmol/L vs. young, 138 ± 13 mmol/L; P = NS). Hepatic DNL was more than twofold higher in the elderly than in the young subjects (elderly, 14.5 ± 1.4% vs. young, 6.9 ± 0.7%; P = 0.00015) and was associated with approximately threefold higher postprandial hepatic triglyceride (TG) content (P < 0.005) and increased fasting plasma TGs (elderly, 1.19 ± 0.18 mmol/L vs. young, 0.74 ± 0.11 mmol/L; P = 0.02). These results strongly support the hypothesis that muscle insulin resistance in aging promotes hyperlipidemia and NAFLD by altering the pattern of postprandial carbohydrate storage away from muscle glycogen and into hepatic DNL.

  6. Occlusal force, electromyographic activity of masticatory muscles and mandibular flexure of subjects with different facial types

    Directory of Open Access Journals (Sweden)

    William Custodio

    2011-08-01

    Full Text Available OBJECTIVE: The aim of this study was to evaluate whether vertical facial patterns influence maximal occlusal force (MOF, masticatory muscle electromyographic (EMG activity, and medial mandibular flexure (MMF. MATERIAL AND METHODS: Seventy-eight dentate subjects were divided into 3 groups by Ricketts's analysis: brachyfacial, mesofacial and dolychofacial. Maximum occlusal force in the molar region was bilaterally measured with a force transducer. The electromyographic activities of the masseter and anterior temporal muscles were recorded during maximal voluntary clenching. Medial mandibular flexure was calculated by subtracting the intermolar distance of maximum opening or protrusion from the distance in the rest position. The data were analyzed using ANOVA followed by Tukey's HSD test. The significance level was set at 5%. RESULTS: Data on maximum occlusal force showed that shorter faces had higher occlusal forces (P<0.0001. Brachyfacial subjects presented higher levels of masseter electromyographic activity and medial mandibular flexure, followed by the mesofacial and dolychofacial groups. Additionally, dolychofacial subjects showed significantly lower electromyographic temporalis activities (P<0.05. CONCLUSION: Within the limitations of the study, it may be concluded that maximum occlusal force, masticatory muscle activity and medial mandibular flexure were influenced by the vertical facial pattern.

  7. Contractions but not AICAR increase FABPpm content in rat muscle sarcolemma

    DEFF Research Database (Denmark)

    Jeppesen, Jacob; Albers, Peter; Luiken, Joost J.

    2009-01-01

    In the present study, it was investigated whether acute muscle contractions in rat skeletal muscle increased the protein content of FABPpm in the plasma membrane. Furthermore, the effect of AICAR stimulation on FAT/CD36 and FABPpm protein content in sarcolemma of rat skeletal muscle was evaluated...

  8. Relationships of Muscle Function and Subjective Knee Function in Patients After ACL Reconstruction.

    Science.gov (United States)

    Bodkin, Stephan; Goetschius, John; Hertel, Jay; Hart, Joe

    2017-07-01

    After anterior cruciate ligament reconstruction (ACLR), relationships between objective measures of muscle function and patient-reported outcomes may change over time. Examining these measures at different time frames after surgery may help develop individualized approaches to improve post-ALCR analysis. To examine the associations between subjective knee function and lower-extremity muscle function in individual patients at various time points after ACLR. Descriptive laboratory study. Fifty-one participants who underwent primary, unilateral ACLR (15 males, 36 females; mean age, 22.9 ± 4.5 years; mean height, 172.4 ± 10.1 cm; mean weight, 68.7 ± 13.1 kg) were separated into 3 groups depending on time since surgery (early, 5 years). Subjective knee function was quantified using the International Knee Documentation Committee (IKDC) subjective knee form and the Knee injury and Osteoarthritis Outcome Score (KOOS). Isometric knee extension and flexion strength were collected at 90 deg/s. Single-leg hop performance was measured using the single hop, triple hop, cross-over hop, and 6-m timed hop. Coefficient correlations were calculated between subjective knee function and objective measures of muscle function for each group. The early group demonstrated moderate correlations between the KOOS and unilateral measures of flexion peak torque (r = 0.514, P = .035) and flexion power (r = 0.54, P = .027). The middle group demonstrated the strongest correlations between the KOOS and symmetry measures of the single hop (r = 0.69, P = .002) and extension work (r = 0.71, P = .002) as well as unilateral measures of the triple hop (r = 0.52, P = .034) and extension work (r = 0.66, P = .004). The late group demonstrated strong correlations between the 6-m timed hop symmetry and the IKDC (r = 0.716, P = .001) and KOOS (r = 0.71, P = .001). Patients with a post-ACLR status of less than 2 years exhibited stronger relationships with unilateral strength measures to subjective function

  9. Muscle Synergies Facilitate Computational Prediction of Subject-Specific Walking Motions

    Science.gov (United States)

    Meyer, Andrew J.; Eskinazi, Ilan; Jackson, Jennifer N.; Rao, Anil V.; Patten, Carolynn; Fregly, Benjamin J.

    2016-01-01

    Researchers have explored a variety of neurorehabilitation approaches to restore normal walking function following a stroke. However, there is currently no objective means for prescribing and implementing treatments that are likely to maximize recovery of walking function for any particular patient. As a first step toward optimizing neurorehabilitation effectiveness, this study develops and evaluates a patient-specific synergy-controlled neuromusculoskeletal simulation framework that can predict walking motions for an individual post-stroke. The main question we addressed was whether driving a subject-specific neuromusculoskeletal model with muscle synergy controls (5 per leg) facilitates generation of accurate walking predictions compared to a model driven by muscle activation controls (35 per leg) or joint torque controls (5 per leg). To explore this question, we developed a subject-specific neuromusculoskeletal model of a single high-functioning hemiparetic subject using instrumented treadmill walking data collected at the subject’s self-selected speed of 0.5 m/s. The model included subject-specific representations of lower-body kinematic structure, foot–ground contact behavior, electromyography-driven muscle force generation, and neural control limitations and remaining capabilities. Using direct collocation optimal control and the subject-specific model, we evaluated the ability of the three control approaches to predict the subject’s walking kinematics and kinetics at two speeds (0.5 and 0.8 m/s) for which experimental data were available from the subject. We also evaluated whether synergy controls could predict a physically realistic gait period at one speed (1.1 m/s) for which no experimental data were available. All three control approaches predicted the subject’s walking kinematics and kinetics (including ground reaction forces) well for the model calibration speed of 0.5 m/s. However, only activation and synergy controls could predict the

  10. Electromyographic study of the flexor muscles of the elbow articulation in weightlifting trained subjects.

    Science.gov (United States)

    Bankoff, A D P; Gushi, M S; Boer, N P

    2007-01-01

    The purpose of this work was to register the electromyography data of the muscles brachialis, biceps brachii long portion, biceps brachii short portion and brachioradialis in the movements of elbow flexion, in the "Larry Scott" bench, in supination and pronation positions, in weightlifting trained subjects. Ten male right-handed subjects were selected, with at least one-year experience in weightlifting exercises, without previous neuromuscular diseases, age between 21 and 26 years. After taking the "Maximum Load" (M.L.) test, or a maximum repetition, we had the percent pattern to establish the loads used in the tests, which was 80%0 of the M. L. For the electromyography records was used a six-channel electromyography (lynx) and the AqDados software in four different moments for each subject: an isometric phase lasting five seconds in supination (1), keeping a 90 degrees angle between the arm and forearm; another one in isometric pronation (2); ten repetitions lasting fifty seconds in supination (3); and ten repetitions in pronation (4). The results of the normalization showed a level of similar activation between the involved muscles in one same moment, as much in supination as in pronation. From the analysis of variance ANOVA, having as level of significance p < 0,05, concludes that it did not have significant difference in the performance of these muscles. When compared between itself all the values of p were bigger than 0,05. Of this form we can perceive a joint action of all the flexion muscle of the elbow to resist the load imposed during the effort.

  11. Effects of Traumeel (Tr14 on Exercise-Induced Muscle Damage Response in Healthy Subjects: A Double-Blind RCT

    Directory of Open Access Journals (Sweden)

    Kerstin Muders

    2016-01-01

    Full Text Available The present double-blind, randomized, placebo-controlled clinical trial intended to test whether ingestion of a natural combination medicine (Tr14 tablets affects serum muscle damage and inflammatory immune response after downhill running. 96 male subjects received Tr14 tablets, which consist of 14 diluted biological and mineral components, or a placebo for 72 h after the exercise test, respectively. Changes in postexercise levels of various serum muscle damage and immunological markers were investigated. The area under the curve with respect to the increase (AUCi of perceived pain score and creatine kinase (CK were defined as primary outcome measures. While for CK the p value of the difference between the two groups is borderline, the pain score and muscle strength were not statistically significant. However, a trend towards lower levels of muscle damage (CK, p=0.05; LDH, p=0.06 in the Tr14 group was shown. Less pronounced lymphopenia (p=0.02, a trend towards a lower expression of CD69 count (p=0.07, and antigen-stimulated ICAM-1 (p=0.01 were found in the verum group. The Tr14 group showed a tendentially lower increase of neutrophils (p=0.10, BDNF (p=0.03, stem cell factor (p=0.09, and GM-CSF (p=0.09 to higher levels. The results of the current study indicate that Tr14 seems to limit exercise-induced muscle damage most likely via attenuation of both innate and adaptive immune responses. This study was registered with ClinicalTrials.gov (NCT01912469.

  12. An herbal medicine, Go-sha-jinki-gan (GJG, increases muscle weight in severe muscle dystrophy model mice

    Directory of Open Access Journals (Sweden)

    Yusei Takemoto

    2017-12-01

    Full Text Available Go-sha-jinki-gan (GJG, a traditional Japanese herbal medicine has a clinical implication to alleviate age-related symptoms, especially in some motor disorders. However, the scientific evidence is limited, and there is a possibility to expand the medical application range of GJG. Using senescence-accelerated mice, our group showed that GJG exerted an effect to prevent sarcopenia, the aged-related loss of skeletal muscle. Because muscular dystrophy is characterized by a progressive loss of skeletal muscle, we examined the effects of GJG on a mouse model of muscular dystrophy. Using a newly established mouse model for Duchenne muscular dystrophy (DMD, DBA/2-mdx, we showed that GJG significantly increased the body and skeletal muscle weights in comparison to the control DBA/2-mdx mice, regardless of gender. The increased skeletal muscle mass resulted from an increment in the myofiber size, but not from the myofiber number. Both the skeletal muscle regenerative ability and the accumulation of fibrosis (the dystrophic pathology in GJG-fed DBA/2-mdx mice were comparable to those in control DBA/2-mdx mice, suggesting that the cellular target of GJG is myofibers, with no contribution from the muscle satellite cells neither in an direct nor in an indirect manner. Taken together, GJG increased the skeletal muscle mass in a mouse model of muscular dystrophy, in addition to our previously tested sarcopenia mouse model.

  13. In Graves' disease, increased muscle tension and reduced elasticity of affected muscles is primarily caused by active muscle contraction

    NARCIS (Netherlands)

    H.J. Simonsz (Huib); G. Kommerell (Guntram)

    1989-01-01

    textabstractIn three patients with Graves' disease of recent onset, length-tension diagrams were made during surgery for squint under eyedrop anesthesia, while the other eye looked ahead, into the field of action, or out of the field of action of the muscle that was measured. The affected muscles

  14. Shoulder muscle activation during stable and suspended push-ups at different heights in healthy subjects.

    Science.gov (United States)

    Borreani, Sebastien; Calatayud, Joaquin; Colado, Juan C; Tella, Victor; Moya-Nájera, Diego; Martin, Fernando; Rogers, Michael E

    2015-08-01

    To analyze shoulder muscle activation when performing push-ups under different stability conditions and heights. Comparative study by repeated measures. Valencia University laboratory. 29 healthy males participated. Subjects performed 3 push-ups each with their hands at 2 different heights (10 vs. 65 cm) under stable conditions and using a suspension device. Push-up speed was controlled and the testing order was randomized. The average amplitudes of the electromyographic root mean square of the long head of the triceps brachii (TRICEP), upper trapezius (TRAPS), anterior deltoid (DELT) and clavicular pectoralis (PEC) were recorded. The electromyographic signals were normalized to the maximum voluntary isometric contraction (MVIC). Suspended push-ups at 10 cm resulted in greater activation in the TRICEP (17.14 ± 1.31 %MVIC vs. 37.03 ± 1.80 %MVIC) and TRAPS (5.83 ± 0.58 %MVIC vs. 14.69 ± 1.91 %MVIC) than those performed on the floor. For DELT and PEC similar or higher activation was found performing the push-ups on the floor, respectively. Height determines different muscle activation patterns. Stable push-ups elicit similar PEC and higher DELT muscle activation, being greater at 10 cm; whereas suspended push-ups elicit greater TRAPS and TRICEP muscle activation, being greater at 65 cm. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. PROGRESSIVE MUSCLE RELAXATION INCREASE PEAK EXPIRATORY FLOW RATE ON CHRONIC OBSTRUCTIVE PULMONARY DISEASE PATIENTS

    Directory of Open Access Journals (Sweden)

    Tintin Sukartini

    2017-07-01

    Full Text Available Introduction: Limited progressive air flow in Chronic Obstructive Pulmonary Disease (COPD can caused by small airway disease (bronchiolitis obstructive and loss of elasticity of the lung (emphysema. Further it can be decreasing the quality of life in COPD patients because dyspnea and uncomfortable in activity. Progressive muscle relaxation (PMR is one of the relaxation technique that can repair pulmonary ventilation by decreasing chronic constriction of the respiratory muscles. The objective of this study was to analyze the effect of progressive muscle relaxation on raised peak expiratory flow rate (PEFR. Method: A pre-experimental one group pre-post test design was used in this study. Population was all of the COPD patients at Pulmonary Specialist Polyclinic Dr Mohamad Soewandhie Surabaya. There were 8 respondents taken by using purposive sampling. PEFR was counted by using peak flow meter every six day. Data were analyzed by using Paired t-Test with significance level  p≤0.05. Result: The result showed that PMR had significance level on increasing of PEFR (p=0.012. Discussion: It can be concluded that PMR has an effect on raise PEFR. Further studies are recommended to measure the effect of PMR on respiratory rate (RR, heart rate (HR subjective dyspnoe symptoms, forced expiration volume on the first minute (FEV1 and mid maximum flow rate (MMFR in COPD patients.

  16. Muscle contraction induced arterial shear stress increases endothelial nitric oxide synthase phosphorylation in humans.

    Science.gov (United States)

    Casey, Darren P; Ueda, Kenichi; Wegman-Points, Lauren; Pierce, Gary L

    2017-10-01

    We determined if local increases in brachial artery shear during repetitive muscle contractions induce changes in protein expression of endothelial nitric oxide synthase (eNOS) and/or phosphorylated (p-)eNOS at Ser1177, the primary activation site on eNOS, in endothelial cells (ECs) of humans. Seven young male subjects (25 ± 1 yr) performed 20 separate bouts (3 min each) of rhythmic forearm exercise at 20% of maximum over a 2-h period. Each bout of exercise was separated by 3 min of rest. An additional six male subjects (24 ± 1 yr) served as time controls (no exercise). ECs were freshly isolated from the brachial artery using sterile J-wires through an arterial catheter at baseline and again after the 2-h exercise or time control period. Expression of eNOS or p-eNOS Ser1177 in ECs was determined via immunofluorescence. Brachial artery mean shear rate was elevated compared with baseline and the time control group throughout the 2-h exercise protocol (P 0.05 for both). Our novel results suggest that elevations in brachial artery shear increase eNOS Ser1177 phosphorylation in the absence of changes in total eNOS in ECs of young healthy male subjects, suggesting that this model is sufficient to alter posttranslational modification of eNOS activity in vivo in humans.NEW & NOTEWORTHY Elevations in brachial artery shear in response to forearm exercise increased endothelial nitric oxide synthase Ser1177 phosphorylation in brachial artery endothelial cells of healthy humans. Our present study provides the first evidence in humans that muscle contraction-induced increases in conduit arterial shear lead to in vivo posttranslational modification of endothelial nitric oxide synthase activity in endothelial cells. Copyright © 2017 the American Physiological Society.

  17. Exercise training increases sarcolemmal and mitochondrial fatty acid transport proteins in human skeletal muscle

    National Research Council Canada - National Science Library

    Talanian, Jason L; Holloway, Graham P; Snook, Laelie A; Heigenhauser, George J F; Bonen, Arend; Spriet, Lawrence L

    2010-01-01

    ... examined. Therefore, we determined whether high-intensity interval training (HIIT) increased total skeletal muscle, sarcolemmal, and mitochondrial membrane fatty acid transport protein contents...

  18. Evaluation of masseter muscles in relation to treatment with removable bite-blocks in dolichofacial growing subjects: A prospective controlled study.

    Science.gov (United States)

    Lione, Roberta; Kiliaridis, Stavros; Noviello, Andrea; Franchi, Lorenzo; Antonarakis, Gregory S; Cozza, Paola

    2017-06-01

    The aim of this prospective study was to evaluate the effects of posterior bite-blocks on masseter muscles and on facial growth in prepubertal dolichofacial subjects. The treatment group comprised 21 consecutive prepubertal dolichofacial patients treated with rapid maxillary expansion followed by mandibular removable bite-blocks. Lateral cephalograms and ultrasonographic scans of the masseter muscles were made before (T1) and after (T2) treatment with bite-blocks. The treatment group was compared with a control group of 21 subjects matched for sex, age, and skeletal vertical pattern. An independent samples t test was used to compare the T1 to T2 changes in ultrasonographic scan measurements between the treatment group and the control group, and the T1 to T2 cephalometric changes in the treatment group. Regression analysis was performed to investigate associations between masseter muscle thickness and cephalometric treatment outcomes. Masseter muscle thickness showed a statistically significant decrease (-0.7 mm) in the treatment group compared with an increase (+0.6 mm) in the control group. A significant anterior rotation of the mandibular plane was observed in the treatment group as well as significant increases in overbite (1.8 mm) and total posterior facial height (1.5 mm). No significant associations were found between masseter muscle thickness and treatment outcomes apart from a tendency for overbite to increase more in subjects with thicker muscles. Treatment with removable bite-blocks produced a decrease in masseter muscle thickness and a reduction in vertical facial dimensions due to upward and forward rotation of the mandible. No significant correlation was found between the pretreatment masseter muscle thickness and the T1 to T2 cephalometric changes in the treatment group. Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  19. Glenohumeral contact forces and muscle forces evaluated in wheelchair-related activities of daily living in able-bodied subjects versus subjects with paraplegia and tetraplegia

    NARCIS (Netherlands)

    van Drongelen, S.; van der Woude, L.H.V.; Janssen, T.W.J.; Angenot, E.D.L.; Chadwick, E.K.J.; Veeger, H.E.J.

    2005-01-01

    Objective: To estimate the differences in glenohumeral contact forces and shoulder muscle forces between able-bodied subjects and subjects with paraplegia and tetraplegia during wheelchair-related activities of daily living (ADLs). Design: Kinematics and external forces were measured during

  20. Glenohumeral contact forces and muscle forces evaluated in wheelchair-related activities of daily living in able-bodied subjects versus subjects with paraplegia and tetraplegia

    NARCIS (Netherlands)

    van Drongelen, S; van der Woude, LH; Janssen, Thomas W. J.; Angenot, EL; Chadwick, EK; Veeger, DirkJan (H. E. J.)

    Objective: To estimate the differences in glenohumeral contact forces and shoulder muscle forces between able-bodied subjects and subjects with paraplegia and tetraplegia during wheelchair-related activities of daily living (ADLs). Design: Kinematics and external forces were measured during

  1. Glenohumeral contact forces and muscle forces evaluated in wheelchair-related activities of daily living in able-bodied subjects versus subjects with paraplegia and tetraplegia

    NARCIS (Netherlands)

    van Drongelen, Stefan; van der Woude, Lucas H; Janssen, Thomas W; Angenot, Edmond L; Chadwick, Edward K; Veeger, Dirkjan H

    OBJECTIVE: To estimate the differences in glenohumeral contact forces and shoulder muscle forces between able-bodied subjects and subjects with paraplegia and tetraplegia during wheelchair-related activities of daily living (ADLs). DESIGN: Kinematics and external forces were measured during

  2. Increased sphingosine-1-phosphate improves muscle regeneration in acutely injured mdx mice.

    Science.gov (United States)

    Ieronimakis, Nicholas; Pantoja, Mario; Hays, Aislinn L; Dosey, Timothy L; Qi, Junlin; Fischer, Karin A; Hoofnagle, Andrew N; Sadilek, Martin; Chamberlain, Jeffrey S; Ruohola-Baker, Hannele; Reyes, Morayma

    2013-08-01

    Presently, there is no effective treatment for the lethal muscle wasting disease Duchenne muscular dystrophy (DMD). Here we show that increased sphingosine-1-phoshate (S1P) through direct injection or via the administration of the small molecule 2-acetyl-4(5)-tetrahydroxybutyl imidazole (THI), an S1P lyase inhibitor, has beneficial effects in acutely injured dystrophic muscles of mdx mice. We treated mdx mice with and without acute injury and characterized the histopathological and functional effects of increasing S1P levels. We also tested exogenous and direct administration of S1P on mdx muscles to examine the molecular pathways under which S1P promotes regeneration in dystrophic muscles. Short-term treatment with THI significantly increased muscle fiber size and extensor digitorum longus (EDL) muscle specific force in acutely injured mdx limb muscles. In addition, the accumulation of fibrosis and fat deposition, hallmarks of DMD pathology and impaired muscle regeneration, were lower in the injured muscles of THI-treated mdx mice. Furthermore, increased muscle force was observed in uninjured EDL muscles with a longer-term treatment of THI. Such regenerative effects were linked to the response of myogenic cells, since intramuscular injection of S1P increased the number of Myf5nlacz/+ positive myogenic cells and newly regenerated myofibers in injured mdx muscles. Intramuscular injection of biotinylated-S1P localized to muscle fibers, including newly regenerated fibers, which also stained positive for S1P receptor 1 (S1PR1). Importantly, plasma membrane and perinuclear localization of phosphorylated S1PR1 was observed in regenerating muscle fibers of mdx muscles. Intramuscular increases of S1P levels, S1PR1 and phosphorylated ribosomal protein S6 (P-rpS6), and elevated EDL muscle specific force, suggest S1P promoted the upregulation of anabolic pathways that mediate skeletal muscle mass and function. These data show that S1P is beneficial for muscle regeneration and

  3. Assessment of muscle function using hybrid PET/MRI: comparison of {sup 18}F-FDG PET and T2-weighted MRI for quantifying muscle activation in human subjects

    Energy Technology Data Exchange (ETDEWEB)

    Haddock, Bryan; Holm, Soeren; Poulsen, Jakup M.; Enevoldsen, Lotte H.; Larsson, Henrik B.W.; Kjaer, Andreas; Suetta, Charlotte [Rigshospitalet Glostrup, Copenhagen University Hospital, Department of Clinical Physiology, Nuclear Medicine and PET, Glostrup (Denmark)

    2017-04-15

    The aim of this study was to determine the relationship between relative glucose uptake and MRI T{sub 2} changes in skeletal muscles following resistance exercise using simultaneous PET/MRI scans. Ten young healthy recreationally active men (age 21 - 28 years) were injected with {sup 18}F-FDG while activating the quadriceps of one leg with repeated knee extension exercises followed by hand-grip exercises for one arm. Immediately following the exercises, the subjects were scanned simultaneously with {sup 18}F-FDG PET/MRI and muscle groups were evaluated for increases in {sup 18}F-FDG uptake and MRI T{sub 2} values. A significant linear correlation between {sup 18}F-FDG uptake and changes in muscle T{sub 2} (R {sup 2} = 0.71) was found. for both small and large muscles and in voxel to voxel comparisons. Despite large intersubject differences in muscle recruitment, the linear correlation between {sup 18}F-FDG uptake and changes in muscle T{sub 2} did not vary among subjects. This is the first assessment of skeletal muscle activation using hybrid PET/MRI and the first study to demonstrate a high correlation between {sup 18}F-FDG uptake and changes in muscle T{sub 2} with physical exercise. Accordingly, it seems that changes in muscle T{sub 2} may be used as a surrogate marker for glucose uptake and lead to an improved insight into the metabolic changes that occur with muscle activation. Such knowledge may lead to improved treatment strategies in patients with neuromuscular pathologies such as stroke, spinal cord injuries and muscular dystrophies. (orig.)

  4. Physical activity opposes the age-related increase in skeletal muscle and plasma endothelin-1 levels and normalizes plasma endothelin-1 levels in individuals with essential hypertension

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Mortensen, Stefan Peter; Hellsten, Ylva

    2013-01-01

    AIMS: Endothelin-1 has potent constrictor and proliferative activity in vascular smooth muscle, and essential hypertension and aging are associated with increased endothelin-1-mediated vasoconstrictor tone. The aim of this study was to investigate the effect of physical activity, hypertension...... and age on endothelin-1 levels in plasma and skeletal muscle and endothelin receptors in skeletal muscle in human subjects. METHODS: In study 1, normotensive (46 ± 1 years, n = 11) and hypertensive (47 ± 1 years, n = 10) subjects were studied before and after 8 weeks of aerobic exercise training. In study...... were higher in hypertensive than normotensive individuals. Eight weeks of exercise training normalized plasma endothelin-1 levels in the hypertensive subjects and increased the protein expression of the ET(A) receptor in skeletal muscle of normotensive subjects. Similarly, individuals that had...

  5. E-wars, an increasing subject in international journalism

    OpenAIRE

    Caminos Marcet, José María; Armentia Vizuete, José Ignacio; Marín Murillo, Flora

    2013-01-01

    The aim of this article is to point out the main difficulties that journalists of international information have to discuss about the subject of the cyber wars (e-wars) or cyber attacks, difficulties who obviously are transferred to the audiences. Indeed, new technologies of information and communication have developed their own destructive capability in the form of cyber-attacks. These can be applied to other conflicts or establish their own strategies for foggy actors ranging from superpowe...

  6. Leg general muscle moment and power patterns in able-bodied subjects during recumbent cycle ergometry with ankle immobilization.

    Science.gov (United States)

    Szecsi, J; Straube, A; Fornusek, C

    2014-11-01

    Rehabilitation of persons with pareses commonly uses recumbent pedalling and a rigid pedal boot that fixes the ankle joint from moving. This study was performed to provide general muscle moments (GMM) and joint power data from able-bodied subjects performing recumbent cycling at two workloads. Twenty-six able-bodied subjects pedalled a stationary recumbent tricycle at 60 rpm during passive cycling and at two workloads (low 15 W and high 40 W per leg) while leg kinematics and pedal forces were recorded. GMM and power were calculated using inverse dynamic equations. During the high workload, the hip and knee muscles produced extensor/flexor moments throughout the extensions/flexions phases of the joints. For low workload, a prolonged (crank angle 0-258°) hip extension moment and a shortened range (350-150°) of knee extension moment were observed compared to the corresponding extension phases of each joint. The knee and hip joints generated approximately equal power. At the high workload the hip and knee extensors generated increased power in the propulsion phase. For the first time, this study provides GMM and power patterns for able-bodied subjects performing recumbent cycling with an immobilized ankle. The patterns showed greater similarities to upright cycling with a free ankle, than previously supposed. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.

  7. Short Term Effects of Neurodynamic Stretching and Static Stretching Techniques on Hamstring Muscle Flexibility in Healthy Male Subjects

    Directory of Open Access Journals (Sweden)

    Adel Rashad Ahmed

    2016-05-01

    Full Text Available Flexibility is a key component of rehabilitation and inadequate muscle extensibility remains a commonly accepted factor for musculoskeletal disorders. Studies on the most optimal technique for improving muscle flexibility are a widely debated. The aim of the study was to compare the effectiveness of neurodynamic and static stretching techniques on hamstring flexibility in healthy male subjects. This study was a randomized experimental trial; forty healthy male subjects with hamstring tightness were randomly divided into two equal groups: The neurodynamic group and the static stretching group. Treatment was given for 5 consecutive days and the outcomes were measured using Active knee Extension Test and Straight Leg Raising. There was a significant improvement in hamstring flexibility following application of both neurodynamic and static stretching but the improvement in the neurodynamic group (p<0.001 was better than that of the static group (p<0.02. Results suggest that a neurodynamic stretching could increase hamstring flexibility to a greater extent than static stretching in healthy male subjects with a tight hamstring.

  8. Increased lower limb muscle coactivation reduces gait performance and increases metabolic cost in patients with hereditary spastic paraparesis.

    Science.gov (United States)

    Rinaldi, Martina; Ranavolo, Alberto; Conforto, Silvia; Martino, Giovanni; Draicchio, Francesco; Conte, Carmela; Varrecchia, Tiwana; Bini, Fabiano; Casali, Carlo; Pierelli, Francesco; Serrao, Mariano

    2017-10-01

    The aim of this study was to investigate the lower limb muscle coactivation and its relationship with muscles spasticity, gait performance, and metabolic cost in patients with hereditary spastic paraparesis. Kinematic, kinetic, electromyographic and energetic parameters of 23 patients and 23 controls were evaluated by computerized gait analysis system. We computed ankle and knee antagonist muscle coactivation indexes throughout the gait cycle and during the subphases of gait. Energy consumption and energy recovery were measured as well. In addition to the correlation analysis between coactivation indexes and clinical variables, correlations between coactivation indexes and time-distance, kinematic, kinetic, and energetic parameters were estimated. Increased coactivity indexes of both knee and ankle muscles throughout the gait cycle and during the subphases of gait were observed in patients compared with controls. Energetic parameters were significantly higher in patients than in controls. Both knee and ankle muscle coactivation indexes were positively correlated with knee and ankle spasticity (Ashworth score), respectively. Knee and ankle muscle coactivation indexes were both positively correlated with energy consumption and both negatively correlated with energy recovery. Positive correlations between the Ashworth score and lower limb muscle coactivation suggest that abnormal lower limb muscle coactivation in patients with hereditary spastic paraparesis reflects a primary deficit linked to lower limb spasticity. Furthermore, these abnormalities influence the energetic mechanisms during walking. Identifying excessive muscle coactivation may be helpful in individuating the rehabilitative treatments and designing specific orthosis to restrain spasticity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Relations between muscle endurance and subjectively reported fatigue, walking capacity, and participation in mildly affected adolescents with cerebral palsy

    NARCIS (Netherlands)

    Eken, Maaike M.; Houdijk, Han; Doorenbosch, Caroline A. M.; Kiezebrink, Francisca E. M.; van Bennekom, Coen A. M.; Harlaar, Jaap; Dallmeijer, Annet J.

    2016-01-01

    To investigate the relation between muscle endurance and subjectively reported fatigue, walking capacity, and participation in mildly affected adolescents with cerebral palsy (CP) and peers with typical development. In this case-control study, knee extensor muscle endurance was estimated from

  10. Ca(2+) leakage out of the sarcoplasmic reticulum is increased in type I skeletal muscle fibres in aged humans.

    Science.gov (United States)

    Lamboley, C R; Wyckelsma, V L; McKenna, M J; Murphy, R M; Lamb, G D

    2016-01-15

    The amount of Ca(2+) stored in the sarcoplasmic reticulum (SR) of muscle fibres is decreased in aged individuals, and an important question is whether this results from increased Ca(2+) leakage out through the Ca(2+) release channels (ryanodine receptors; RyRs). The present study examined the effects of blocking the RyRs with Mg(2+), or applying a strong reducing treatment, on net Ca(2+) accumulation by the SR in skinned muscle fibres from Old (∼70 years) and Young (∼24 years) adults. Raising cytoplasmic [Mg(2+)] and reducing treatment increased net SR Ca(2+) accumulation in type I fibres of Old subjects relative to that in Young. The densities of RyRs and dihydropyridine receptors were not significantly changed in the muscle of Old subjects. These findings indicate that oxidative modification of the RyRs causes increased Ca(2+) leakage from the SR in muscle fibres in Old subjects, which probably deleteriously affects normal muscle function both directly and indirectly. The present study examined whether the lower Ca(2+) storage levels in the sarcoplasmic reticulum (SR) in vastus lateralis muscle fibres in Old (70 ± 4 years) relative to Young (24 ± 4 years) human subjects is the result of increased leakage of Ca(2+) out of the SR through the Ca(2+) release channels/ryanodine receptors (RyRs) and due to oxidative modification of the RyRs. SR Ca(2+) accumulation in mechanically skinned muscle fibres was examined in the presence of 1, 3 or 10 mm cytoplasmic Mg(2+) because raising [Mg(2+)] strongly inhibits Ca(2+) efflux through the RyRs. In type I fibres of Old subjects, SR Ca(2+) accumulation in the presence of 1 mm Mg(2+) approached saturation at shorter loading times than in Young subjects, consistent with Ca(2+) leakage limiting net uptake, and raising [Mg(2+)] to 10 mm in such fibres increased maximal SR Ca(2+) accumulation. No significant differences were seen in type II fibres. Treatment with dithiothreitol (10 mm for 5 min), a strong reducing agent, also

  11. Venous capacity, venous refill time and the effectiveness of the calf muscle pump in normal subjects.

    Science.gov (United States)

    Barendsen, G J; van den Berg, J W

    1984-03-01

    With strain gauge plethysmography various procedures to assess the competence of the venous system in the lower leg were compared in 10 normal subjects. The reproducibility and ease of use were established, and normal values were obtained. It is concluded, that measurements in the sitting position are preferable to those in the standing position. To measure the venous capacity, the dependency test is the method of choice. Rhythmic exercise to assess the effectiveness of the calf muscle pump can be restricted to five successive contractions. The refill time after exercise is not a suitable parameter to assess the competence of the venous valves.

  12. Evaluation of the effects of the Arm Light Exoskeleton on movement execution and muscle activities: a pilot study on healthy subjects.

    Science.gov (United States)

    Pirondini, Elvira; Coscia, Martina; Marcheschi, Simone; Roas, Gianluca; Salsedo, Fabio; Frisoli, Antonio; Bergamasco, Massimo; Micera, Silvestro

    2016-01-23

    Exoskeletons for lower and upper extremities have been introduced in neurorehabilitation because they can guide the patient's limb following its anatomy, covering many degrees of freedom and most of its natural workspace, and allowing the control of the articular joints. The aims of this study were to evaluate the possible use of a novel exoskeleton, the Arm Light Exoskeleton (ALEx), for robot-aided neurorehabilitation and to investigate the effects of some rehabilitative strategies adopted in robot-assisted training. We studied movement execution and muscle activities of 16 upper limb muscles in six healthy subjects, focusing on end-effector and joint kinematics, muscle synergies, and spinal maps. The subjects performed three dimensional point-to-point reaching movements, without and with the exoskeleton in different assistive modalities and control strategies. The results showed that ALEx supported the upper limb in all modalities and control strategies: it reduced the muscular activity of the shoulder's abductors and it increased the activity of the elbow flexors. The different assistive modalities favored kinematics and muscle coordination similar to natural movements, but the muscle activity during the movements assisted by the exoskeleton was reduced with respect to the movements actively performed by the subjects. Moreover, natural trajectories recorded from the movements actively performed by the subjects seemed to promote an activity of muscles and spinal circuitries more similar to the natural one. The preliminary analysis on healthy subjects supported the use of ALEx for post-stroke upper limb robotic assisted rehabilitation, and it provided clues on the effects of different rehabilitative strategies on movement and muscle coordination.

  13. Short Term Effects of Neurodynamic Stretching and Static Stretching Techniques on Hamstring Muscle Flexibility in Healthy Male Subjects

    OpenAIRE

    Adel Rashad Ahmed; Ahmed Fathy Samhan

    2016-01-01

    Flexibility is a key component of rehabilitation and inadequate muscle extensibility remains a commonly accepted factor for musculoskeletal disorders. Studies on the most optimal technique for improving muscle flexibility are a widely debated. The aim of the study was to compare the effectiveness of neurodynamic and static stretching techniques on hamstring flexibility in healthy male subjects. This study was a randomized experimental trial; forty healthy male subjects with hamstr...

  14. Intra-Rater Reliability of Rehabilitative Ultrasound Imaging for Multifidus Muscles Thickness and Cross Section Area in Healthy Subjects

    OpenAIRE

    Hosseinifar, Mohammad; Akbari, Asghar; Ghiasi, Fateme

    2015-01-01

    Introduction: Rehabilitative Ultrasound Imaging (RUSI) must be valuable method for research and rehabilitation. So, the reliability of its measurements must be determined. The purpose of this study was to evaluate the intra-rater reliability of RUSI for measurement of multifidus (MF) muscles cross section areas (CSAs), bladder wall diameter, and thickness of MF muscles between 2 sessions in healthy subjects. Method: Fifteen healthy subjects through simple non-probability sampling participated...

  15. Muscle Volume Increases Following 16 Weeks of Resistive Exercise Training with the Advanced Resistive Exercise Device (ARED) and Free Weights

    Science.gov (United States)

    Nash, R. E.; Loehr, J. A.; Lee, S. M. C.; English, K. L.; Evans, H.; Smith, S. A.; Hagan, R. D.

    2009-01-01

    Space flight-induced muscle atrophy, particularly in the postural and locomotorymuscles, may impair task performance during long-duration space missions and planetary exploration. High intensity free weight (FW) resistive exercise training has been shown to prevent atrophy during bed rest, a space flight analog. NASA developed the Advanced Resistive Exercise Device (ARED) to simulate the characteristics of FW exercise (i.e. constant mass, inertial force) and to be used as a countermeasure during International Space Station (ISS) missions. PURPOSE: To compare the efficacy of ARED and FW training to induce hypertrophy in specific muscle groups in ambulatory subjects prior to deploying ARED on the ISS. METHODS: Twenty untrained subjects were assigned to either the ARED (8 males, 3 females) or FW (6 males, 3 females) group and participated in a periodizedtraining protocol consisting of squat (SQ), heel raise (HR), and deadlift(DL) exercises 3 d wk-1 for 16 wks. SQ, HR, and DL muscle strength (1RM) was measured before, after 8 wks, and after 16 wks of training to prescribe exercise and measure strength changes. Muscle volume of the vastigroup (V), hamstring group (H), hip adductor group (ADD), medial gastrocnemius(MG), lateral gastrocnemius(LG), and deep posterior muscles including soleus(DP) was measured using MRI pre-and post-training. Consecutive cross-sectional images (8 mm slices with a 2 mm gap) were analyzed and summed. Anatomical references insured that the same muscle sections were analyzed pre-and post-training. Two-way repeated measures ANOVAs (pvolume between training devices. RESULTS: SQ, HR, and DL 1RM increased in both FW (SQ: 49+/-6%, HR: 12+/-2%, DL: 23+/-4%) and ARED (SQ: 31+/-4%, HR: 18+/-2%, DL: 23+/-3%) groups. Both groups increased muscle volume in the V (FW: 13+/-2%, ARED: 10+/-2%), H (FW: 3+/-1%, ARED: 3+/-1 %), ADD (FW: 15=/-2%, ARED: 10+/-1%), LG (FW: 7+/-2%, ARED: 4+/-1%), MG (FW: 7+/-2%, ARED: 5+/-2%), and DP (FW: 2+/-1%; ARED: 2+/-1%) after

  16. Model and Effectiveness of Endurance Exercise to Increase Physical Fitness in Intellectual Disability Subjects with Obesity: A Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Tirza Z Tamin

    2015-04-01

    Full Text Available Aim: to design a model and assess the effectiveness of endurance exercise to increase physical fitness in intelectual disability (ID patients with obesity. Methods: a randomized-controlled clinical trial was performed in ID patients with obesity aged 10-30 years old from all Special School in DKI Jakarta, which were randomly allocated into 3 groups and then given 3 different type of exercises: lower extremity muscles endurance exercise for 20 RM followed by cardiorespiratory endurance exercise for 24-25 minutes (type I, lower extremity muscles endurance exercises for 10 RM followed by cardiorespiratory endurance exercises for 26-27 minutes (type II, and threw a tennis ball with 10 m distance for 10 minutes as control (type III. These program was performed 3 times a week for 4 months. Assesment of the exercise effectiveness was done by measuring maximum load that can be lifted and six-minutes walking test on rectangular track which was converted with the VO2 max prediction formula. Analysis was perfomed with Kruskal Wallis test. Results: two hundred and twelve (212 subjects were included in the study, randomly allocated into three types (I, II, and III of exercises groups. The type II of endurance exercise model was proved to be more effective in increasing lower extremity muscles endurance level compared to type I and III for ID patients with obesity (p<0.05. Meanwhile, type I of endurance exercise model was proved to be more effective in increasing cardiorespiratory endurance level compared to type II and III for ID patients with obesity (p<0.05. Conclusion: lower extremity muscles endurance exercise followed by a cardiorespiratory endurance exercise can be used to increase physical fitness in ID patients with obesity. Key words: intelectual disability patient, obesity, lower extremity muscles and cardiorespiratory endurance exercise, lower extremity muscles endurance level, cardiorespiratory endurance level.

  17. Discrepancies between Skinned Single Muscle Fibres and Whole Thigh Muscle Function Characteristics in Young and Elderly Human Subjects

    Directory of Open Access Journals (Sweden)

    Hyunseok Jee

    2016-01-01

    Full Text Available We aimed to analyse the mechanical properties of skinned single muscle fibres derived from the vastus lateralis (VL muscle in relation to those of the whole intact thigh muscle and to compare any difference between young and older adults. Sixteen young men (29.25±4.65 years, 11 older men (71.45±2.94 years, 11 young women (29.64±4.88 years, and 7 older women (67.29±1.70 years were recruited. In vivo analyses were performed for mechanical properties such as isokinetic performance, isometric torque, and power. Specific force and maximum shortening velocity (Vo were measured with single muscle fibres. Sex difference showed greater impact on the functional properties of both the whole muscle (p<0.01 and single muscle fibres than aging (p<0.05. Sex difference, rather than aging, yielded more remarkable differences in gross mechanical properties in the single muscle fibre study in which significant differences between young men and young women were found only in the cross-sectional area and Vo (p<0.05. Age and sex differences reflect the mechanical properties of both single muscle fibres and whole thigh muscle, with the whole muscle yielding more prominent functional properties.

  18. Mechanisms of quadriceps muscle weakness in knee joint osteoarthritis: the effects of prolonged vibration on torque and muscle activation in osteoarthritic and healthy control subjects

    OpenAIRE

    Rice, David A; McNair, Peter J; Lewis, Gwyn N.

    2011-01-01

    Introduction A consequence of knee joint osteoarthritis (OA) is an inability to fully activate the quadriceps muscles, a problem termed arthrogenic muscle inhibition (AMI). AMI leads to marked quadriceps weakness that impairs physical function and may hasten disease progression. The purpose of the present study was to determine whether γ-loop dysfunction contributes to AMI in people with knee joint OA. Methods Fifteen subjects with knee joint OA and 15 controls with no history of knee joint p...

  19. 20-Hydroxyecdysone increases fiber size in a muscle-specific fashion in rat.

    Science.gov (United States)

    Tóth, Noémi; Szabó, András; Kacsala, Péter; Héger, Júlia; Zádor, Ernö

    2008-09-01

    20-Hydroxyecdysone (20E) is an ecdysteroid hormone that regulates moulting in insects. Interestingly, 20E is also found most abundantly in plant species and has anabolic effects in vertebrates, i.e. increasing muscle size without androgen influence. The effect of 20E on slow and fast fiber types of skeletal muscle has not been reported yet. Here we present that 20E affects the size (cross-sectional area, CSA) of the different fiber types in a muscle-specific manner. The effect on fiber size was modified by the distance from the site of the treatment and the presence of a regenerating soleus muscle in the animal. Besides the fiber size, 20E also increased the myonuclear number in the fibers of normal and regenerating muscles, suggesting the activation of satellite cells. According to our results 20E may provide an alternative for substitution of anabolic-androgenic steroids in therapeutic treatments against muscle atrophy.

  20. Jaw Dysfunction Is Associated with Neck Disability and Muscle Tenderness in Subjects with and without Chronic Temporomandibular Disorders

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    A. Silveira

    2015-01-01

    Full Text Available Purpose. Tender points in the neck are common in patients with temporomandibular disorders (TMD. However, the correlation among neck disability, jaw dysfunction, and muscle tenderness in subjects with TMD still needs further investigation. This study investigated the correlation among neck disability, jaw dysfunction, and muscle tenderness in subjects with and without chronic TMD. Participants. Forty females between 19 and 49 years old were included in this study. There were 20 healthy controls and 20 subjects who had chronic TMD and neck disability. Methods. Subjects completed the neck disability index and the limitations of daily functions in TMD questionnaires. Tenderness of the masticatory and cervical muscles was measured using an algometer. Results. The correlation between jaw disability and neck disability was significantly high (r=0.915, P<0.05. The correlation between level of muscle tenderness in the masticatory and cervical muscles with jaw dysfunction and neck disability showed fair to moderate correlations (r=0.32–0.65. Conclusion. High levels of muscle tenderness in upper trapezius and temporalis muscles correlated with high levels of jaw and neck dysfunction. Moreover, high levels of neck disability correlated with high levels of jaw disability. These findings emphasize the importance of considering the neck and its structures when evaluating and treating patients with TMD.

  1. Subject-specific tendon-aponeurosis definition in Hill-type model predicts higher muscle forces in dynamic tasks.

    Directory of Open Access Journals (Sweden)

    Pauline Gerus

    Full Text Available Neuromusculoskeletal models are a common method to estimate muscle forces. Developing accurate neuromusculoskeletal models is a challenging task due to the complexity of the system and large inter-subject variability. The estimation of muscles force is based on the mechanical properties of tendon-aponeurosis complex. Most neuromusculoskeletal models use a generic definition of the tendon-aponeurosis complex based on in vitro test, perhaps limiting their validity. Ultrasonography allows subject-specific estimates of the tendon-aponeurosis complex's mechanical properties. The aim of this study was to investigate the influence of subject-specific mechanical properties of the tendon-aponeurosis complex on a neuromusculoskeletal model of the ankle joint. Seven subjects performed isometric contractions from which the tendon-aponeurosis force-strain relationship was estimated. Hopping and running tasks were performed and muscle forces were estimated using subject-specific tendon-aponeurosis and generic tendon properties. Two ultrasound probes positioned over the muscle-tendon junction and the mid-belly were combined with motion capture to estimate the in vivo tendon and aponeurosis strain of the medial head of gastrocnemius muscle. The tendon-aponeurosis force-strain relationship was scaled for the other ankle muscles based on tendon and aponeurosis length of each muscle measured by ultrasonography. The EMG-driven model was calibrated twice - using the generic tendon definition and a subject-specific tendon-aponeurosis force-strain definition. The use of subject-specific tendon-aponeurosis definition leads to a higher muscle force estimate for the soleus muscle and the plantar-flexor group, and to a better model prediction of the ankle joint moment compared to the model estimate which used a generic definition. Furthermore, the subject-specific tendon-aponeurosis definition leads to a decoupling behaviour between the muscle fibre and muscle-tendon unit

  2. Exercise training with dietary counselling increases mitochondrial chaperone expression in middle-aged subjects with impaired glucose tolerance

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    Lindström Jaana

    2008-03-01

    Full Text Available Abstract Background Insulin resistance and diabetes are associated with increased oxidative stress and impairment of cellular defence systems. Our purpose was to investigate the interaction between glucose metabolism, antioxidative capacity and heat shock protein (HSP defence in different skeletal muscle phenotypes among middle-aged obese subjects during a long-term exercise and dietary intervention. As a sub-study of the Finnish Diabetes Prevention Study (DPS, 22 persons with impaired glucose tolerance (IGT taking part in the intervention volunteered to give samples from the vastus lateralis muscle. Subjects were divided into two sub-groups (IGTslow and IGTfast on the basis of their baseline myosin heavy chain profile. Glucose metabolism, oxidative stress and HSP expressions were measured before and after the 2-year intervention. Results Exercise training, combined with dietary counselling, increased the expression of mitochondrial chaperones HSP60 and glucose-regulated protein 75 (GRP75 in the vastus lateralis muscle in the IGTslow group and that of HSP60 in the IGTfast group. In cytoplasmic chaperones HSP72 or HSP90 no changes took place. In the IGTslow group, a significant positive correlation between the increased muscle content of HSP60 and the oxygen radical absorbing capacity values and, in the IGTfast group, between the improved VO2max value and the increased protein expression of GRP75 were found. Serum uric acid concentrations decreased in both sub-groups and serum protein carbonyl concentrations decreased in the IGTfast group. Conclusion The 2-year intervention up-regulated mitochondrial HSP expressions in middle-aged subjects with impaired glucose tolerance. These improvements, however, were not correlated directly with enhanced glucose tolerance.

  3. The transgenic expression of human follistatin-344 increases skeletal muscle mass in pigs.

    Science.gov (United States)

    Chang, Fei; Fang, Rui; Wang, Meng; Zhao, Xin; Chang, Wen; Zhang, Zaihu; Li, Ning; Meng, Qingyong

    2017-02-01

    Follistatin (FST), which was first found in the follicles of cattle and pigs, has been shown to be an essential regulator for muscle development. Mice that were genetically engineered to overexpress Fst specifically in muscle had at least twice the amount of skeletal muscle mass as controls; these findings are similar to earlier results obtained in myostatin-knockout mice. However, the role of follistatin in skeletal muscle development has yet to be clarified in livestock. Here, we describe transgenic Duroc pigs that exogenously express Fst specifically in muscle tissue. The transgenic pigs exhibited an increased proportion of skeletal muscle and a reduced proportion of body fat that were similar to those reported in myostatin-null cattle. The lean percentage of lean meat was significantly higher in the F1 generation of TG pigs (72.95 ± 1.0 %) than in WT pigs (69.18 ± 0.97 %) (N = 16, P < 0.05). Myofiber hypertrophy was also observed in the longissimus dorsi of transgenic pigs, possibly contributing to the increased skeletal muscle mass. Western blot analysis showed a significantly reduced level of Smad2 phosphorylation and an increased level of AktS473 phosphorylation in the skeletal muscle tissue of the transgenic pigs. Moreover, no cardiac muscle hypertrophy or reproductive abnormality was observed. These findings indicate that muscle-specific Fst overexpression in pigs enhances skeletal muscle growth, at least partly due to myofiber hypertrophy and providing a promising approach to increase muscle mass in pigs and other livestock.

  4. Noninvasive quantification of muscle oxygen in subjects with and without claudication.

    Science.gov (United States)

    Lee, B Y; Ostrander, E; Karmakar, M; Frenkel, L; Herz, B

    1997-01-01

    The disabling pain of intermittent claudication (IC) arises from oxygen deprivation in the lower limbs during walking. Measurement of the oxygen deficiency within the limb tissue now appears possible with recently expanded understanding of the photon transport through tissue for photons in the visible and near infrared range. Noninvasive measurement consists of preferentially measuring photons that have traveled more deeply into limb tissues and that, therefore, may reach locations of ischemic tissue. Oxygen measurements appear to be possible up to a depth approaching 1.5 cm beneath the surface of the skin. The present study reports on data acquired from the limbs of 11 subjects with IC and 12 subjects without IC. The subjects with IC are patients with clinical findings of claudication based upon segmental Doppler pressure profiles and subjective reports by the patient of pain during exercise. The subjects without IC are individuals with no prior history of ischemic vascular disease. The results consist of photon reflectance measurements at red and infrared wavelengths (approximately 660 nm and 880 nm respectively) taken before, during, and after exercise. Infrared reflectance indices are plotted as well as oxygenation indices generated from combining red and infrared reflectances. A compilation of exercise data shows responses that are generally consistent with the expected physiological responses to mild exercise in subjects with and without IC. We anticipate that the findings of this study may lead to an objective noninvasive testing procedure for measuring the ischemic and exercise-induced changes in muscle oxygenation in the presence of claudication. If the testing of ischemic hypoxia continues to show consistency and accuracy in determining the disability of the subjects with IC, future studies can more effectively test modes of conservative management, such as cessation of smoking, alternative exercise regimens, weight loss, and alternative pharmacological

  5. Myostatin dysfunction impairs force generation in extensor digitorum longus muscle and increases exercise-induced protein efflux from extensor digitorum longus and soleus muscles.

    Science.gov (United States)

    Baltusnikas, Juozas; Kilikevicius, Audrius; Venckunas, Tomas; Fokin, Andrej; Bünger, Lutz; Lionikas, Arimantas; Ratkevicius, Aivaras

    2015-08-01

    Myostatin dysfunction promotes muscle hypertrophy, which can complicate assessment of muscle properties. We examined force generating capacity and creatine kinase (CK) efflux from skeletal muscles of young mice before they reach adult body and muscle size. Isolated soleus (SOL) and extensor digitorum longus (EDL) muscles of Berlin high (BEH) mice with dysfunctional myostatin, i.e., homozygous for inactivating myostatin mutation, and with a wild-type myostatin (BEH+/+) were studied. The muscles of BEH mice showed faster (P myostatin dysfunction leads to impairment in muscle force generating capacity in EDL and increases susceptibility of SOL and EDL to protein loss after exercise.

  6. Equilibrium and muscle flexibility in elderly people subjected to physiotherapeutic intervention

    Directory of Open Access Journals (Sweden)

    Mariane Fernandes Ribeiro

    2016-09-01

    Full Text Available To evaluate the equilibrium and flexibility of elderly people submitted to a training program involving physical therapy exercises. Six elderly people were selected, average age 69.66 years. Wells’s Bench and the Functional Reach Test (FRT plus Timed Up and Go Test (TUG were employed respectively to assess muscle flexibility and balance analysis. Tests were performed before and after the exercise program which consisted of thirty-five 50 min physical therapy group sessions, twice a week, with stretching exercises, gait training, active exercises, postural correction exercises and breathing exercises. Statistical analysis was done with Sigma-Stat® 3.5. Assessments occurred before and after sessions, and the final test was undertaken after 35 sessions. There was a statistically significant increase in the flexibility of the posterior muscle chain. In the TUG test, the group achieved a shorter time after treatment, with statistical significance between tests. There was a statistically significant increase in the average FRT after the sessions. Current study showed better results in the execution of tests evaluated after the program of physiotherapy activities, contributing towards the improvement of muscle flexibility and balance of elderly people.

  7. Dysfunctional parenting styles increase interpersonal sensitivity in healthy subjects.

    Science.gov (United States)

    Otani, Koichi; Suzuki, Akihito; Shibuya, Naoshi; Matsumoto, Yoshihiko; Kamata, Mitsuhiro

    2009-12-01

    The effects of dysfunctional parenting styles on interpersonal sensitivity were studied in 640 Japanese volunteers. Interpersonal sensitivity was assessed by the Interpersonal Sensitivity Measure (IPSM), and perceived parental rearing was evaluated by the Parental Bonding Instrument (PBI), which is consisted of care and protection factors. Parental rearing was classified into 4 types, i.e., optimal parenting (high care/low protection), affectionate constraint (high care/high protection), neglectful parenting (low care/low protection), and affectionless control (low care/high protection). Males with paternal affectionless control showed higher total IPSM scores than those with paternal optimal parenting (p = 0.022). Females with maternal affectionate constraint (p = 0.001), neglectful parenting (p = 0.022), and affectionless control (p = 0.003) showed higher total IPSM scores than those with maternal optimal parenting. In males and females, dysfunctional parenting styles by the opposite-sex parents did not affected total IPSM scores. The present study suggests that in both males and females interpersonal sensitivity is increased by dysfunctional parenting styles by the same-sex parents.

  8. Intra-Rater Reliability of Rehabilitative Ultrasound Imaging for Multifidus Muscles Thickness and Cross Section Area in Healthy Subjects.

    Science.gov (United States)

    Hosseinifar, Mohammad; Akbari, Asghar; Ghiasi, Fateme

    2015-07-07

    Rehabilitative Ultrasound Imaging (RUSI) must be valuable method for research and rehabilitation. So, the reliability of its measurements must be determined. The purpose of this study was to evaluate the intra-rater reliability of RUSI for measurement of multifidus (MF) muscles cross section areas (CSAs), bladder wall diameter, and thickness of MF muscles between 2 sessions in healthy subjects. Fifteen healthy subjects through simple non-probability sampling participated in this single-group repeated-measures reliability study. MF muscles thickness at rest and during contraction, MF muscles CSAs at rest, and bladder diameters at rest and during pelvic floor muscles (PFM) contraction were measured through RUSI. Pearson's correlation coefficient test was used to determine intra-rater reliability of variables. The results showed that intra-class correlation Coefficient (ICCs) values with 95% confidence interval (CI) and the standard error of the measurement (SEM) were good to excellent agreement for a single investigator between measurement occasions. The intra-rater reliability for the bladder wall displacement was high (ICCs for rest and PFM contraction state: 0.96 and 0.95 respectively), for the MF muscles CSAs at the L4 level was good to high (ICCs 0.75 and 0.91 for right (Rt) and left (Lt) side respectively), and for the thickness of MF muscles at two levels, at rest and during two tasks was moderate to high (ICCs: 0.64 to 0.87). The Trans-Abdominal (TA) method of RUSI is a reliable method to quantify the PFM contraction in healthy subjects. Also, the RUSI is a reliable method to measure the MF muscles CSAs, the MF muscles thickness at rest and during functional tasks in healthy subjects.

  9. Deletion of Galgt2 (B4Galnt2) Reduces Muscle Growth in Response to Acute Injury and Increases Muscle Inflammation and Pathology in Dystrophin-Deficient Mice

    Science.gov (United States)

    Xu, Rui; Singhal, Neha; Serinagaoglu, Yelda; Chandrasekharan, Kumaran; Joshi, Mandar; Bauer, John A.; Janssen, Paulus M.L.; Martin, Paul T.

    2016-01-01

    Transgenic overexpression of Galgt2 (official name B4Galnt2) in skeletal muscle stimulates the glycosylation of α dystroglycan (αDG) and the up-regulation of laminin α2 and dystrophin surrogates known to inhibit muscle pathology in mouse models of congenital muscular dystrophy 1A and Duchenne muscular dystrophy. Skeletal muscle Galgt2 gene expression is also normally increased in the mdx mouse model of Duchenne muscular dystrophy compared with the wild-type mice. To assess whether this increased endogenous Galgt2 expression could affect disease, we quantified muscular dystrophy measures in mdx mice deleted for Galgt2 (Galgt2−/−mdx). Galgt2−/− mdx mice had increased heart and skeletal muscle pathology and inflammation, and also worsened cardiac function, relative to age-matched mdx mice. Deletion of Galgt2 in wild-type mice also slowed skeletal muscle growth in response to acute muscle injury. In each instance where Galgt2 expression was elevated (developing muscle, regenerating muscle, and dystrophic muscle), Galgt2-dependent glycosylation of αDG was also increased. Overexpression of Galgt2 failed to inhibit skeletal muscle pathology in dystroglycan-deficient muscles, in contrast to previous studies in dystrophin-deficient mdx muscles. This study demonstrates that Galgt2 gene expression and glycosylation of αDG are dynamically regulated in muscle and that endogenous Galgt2 gene expression can ameliorate the extent of muscle pathology, inflammation, and dysfunction in mdx mice. PMID:26435413

  10. Increased oxidative metabolism and myoglobin expression in zebrafish muscle during chronic hypoxia

    Directory of Open Access Journals (Sweden)

    Richard T. Jaspers

    2014-07-01

    Full Text Available Fish may be extremely hypoxia resistant. We investigated how muscle fibre size and oxidative capacity in zebrafish (Danio rerio adapt during severe chronic hypoxia. Zebrafish were kept for either 3 or 6 weeks under chronic constant hypoxia (CCH (10% air/90%N2 saturated water. We analyzed cross-sectional area (CSA, succinate dehydrogenase (SDH activity, capillarization, myonuclear density, myoglobin (Mb concentration and Mb mRNA expression of high and low oxidative muscle fibres. After 3 weeks of CCH, CSA, SDH activity, Mb concentration, capillary and myonuclear density of both muscle fibre types were similar as under normoxia. In contrast, staining intensity for Mb mRNA of hypoxic high oxidative muscle fibres was 94% higher than that of normoxic controls (P<0.001. Between 3 and 6 weeks of CCH, CSA of high and low oxidative muscle fibres increased by 25 and 30%, respectively. This was similar to normoxic controls. Capillary and myonuclear density were not changed by CCH. However, in high oxidative muscle fibres of fish maintained under CCH, SDH activity, Mb concentration as well as Mb mRNA content were higher by 86%, 138% and 90%, respectively, than in muscle fibres of fish kept under normoxia (P<0.001. In low oxidative muscle fibres, SDH activity, Mb and Mb mRNA content were not significantly changed. Under normoxia, the calculated interstitial oxygen tension required to prevent anoxic cores in muscle fibres (PO2crit of high oxidative muscle fibres was between 1.0 and 1.7 mmHg. These values were similar at 3 and 6 weeks CCH. We conclude that high oxidative skeletal muscle fibres of zebrafish continue to grow and increase oxidative capacity during CCH. Oxygen supply to mitochondria in these fibres may be facilitated by an increased Mb concentration, which is regulated by an increase in Mb mRNA content per myonucleus.

  11. Coordinated increase in skeletal muscle fiber area and expression of IGF-I with resistance exercise in elderly post-operative patients

    DEFF Research Database (Denmark)

    Suetta, Charlotte; Clemmensen, Christoffer; Andersen, Jesper L

    2010-01-01

    Hypertrophy of developing skeletal muscle involves stimulation by insulin-like growth factor-I (IGF-I), however, the role of IGF-I in adult muscle is less clarified. In the present study, the mRNA splice variants of IGF-I (IGF-IEa and MGF) and the changes in muscle fiber cross sectional area after...... and in addition induces marked increases in the expression of IGF-I splice variants, supporting the idea that IGF-I is involved in regulating muscle hypertrophy.......-operated-side served as a within subject control. Muscle biopsies were obtained from the vastus lateralis of both limbs at +2d post-operative (baseline), at 5weeks and 12weeks post-surgery to analyze for changes in type 1 and type 2 muscle fiber area. Changes in expression levels of IGF-I mRNA isoforms were determined...

  12. Motion of the drawing hand induces a progressive increase in muscle activity of the non-dominant hand in Ramachandran's mirror-box therapy.

    Science.gov (United States)

    Furukawa, Kiminobu; Suzuki, Harue; Fukuda, Jun

    2012-11-01

    To observe the real-time muscle activity of bilateral hands while subjects draw circles under 2 conditions: with and without using Ramachandran's mirror-box. A total of 24 healthy volunteers. Subjects drew 4 circles sequentially using their dominant hand with the other hand at rest, both with and without looking at a mirror image. Circles were marked by 8 dots on the paper, which subjects connected up to draw the shape. The activity of the bilateral first dorsal interosseus muscles was recorded using surface electromyography. Muscle activity of the dominant hand remained constant during each task. In contrast, muscle activity of the non-dominant hand increased under the condition of watching the image in the mirror, but was low under the non-watching condition. Furthermore, muscle activity of the non-dominant hand increased over the duration of the task. However, wide variation between subjects was observed under the mirror-image condition. Increased muscle action potential of the non-dominant hand may be induced by the circle drawing task of the dominant hand during Ramachandran's mirror-box therapy, which supports previous observations of increased brain activity caused by watching a mirror image.

  13. Jaw dysfunction is associated with neck disability and muscle tenderness in subjects with and without chronic temporomandibular disorders.

    Science.gov (United States)

    Silveira, A; Gadotti, I C; Armijo-Olivo, S; Biasotto-Gonzalez, D A; Magee, D

    2015-01-01

    Tender points in the neck are common in patients with temporomandibular disorders (TMD). However, the correlation among neck disability, jaw dysfunction, and muscle tenderness in subjects with TMD still needs further investigation. This study investigated the correlation among neck disability, jaw dysfunction, and muscle tenderness in subjects with and without chronic TMD. Participants. Forty females between 19 and 49 years old were included in this study. There were 20 healthy controls and 20 subjects who had chronic TMD and neck disability. Subjects completed the neck disability index and the limitations of daily functions in TMD questionnaires. Tenderness of the masticatory and cervical muscles was measured using an algometer. The correlation between jaw disability and neck disability was significantly high (r = 0.915, P cervical muscles with jaw dysfunction and neck disability showed fair to moderate correlations (r = 0.32-0.65). High levels of muscle tenderness in upper trapezius and temporalis muscles correlated with high levels of jaw and neck dysfunction. Moreover, high levels of neck disability correlated with high levels of jaw disability. These findings emphasize the importance of considering the neck and its structures when evaluating and treating patients with TMD.

  14. Immediate Effects of Neurodynamic Sliding versus Muscle Stretching on Hamstring Flexibility in Subjects with Short Hamstring Syndrome.

    Science.gov (United States)

    Castellote-Caballero, Yolanda; Valenza, Maríe C; Puentedura, Emilio J; Fernández-de-Las-Peñas, César; Alburquerque-Sendín, Francisco

    2014-01-01

    Background. Hamstring injuries continue to affect active individuals and although inadequate muscle extensibility remains a commonly accepted factor, little is known about the most effective method to improve flexibility. Purpose. To determine if an isolated neurodynamic sciatic sliding technique would improve hamstring flexibility to a greater degree than stretching or a placebo intervention in asymptomatic subjects with short hamstring syndrome (SHS). Study Design. Randomized double-blinded controlled trial. Methods. One hundred and twenty subjects with SHS were randomized to 1 of 3 groups: neurodynamic sliding, hamstring stretching, and placebo control. Each subject's dominant leg was measured for straight leg raise (SLR) range of motion (ROM) before and after interventions. Data were analyzed with a 3 × 2 mixed model ANOVA followed by simple main effects analyses. Results. At the end of the study, more ROM was observed in the Neurodynamic and Stretching groups compared to the Control group and more ROM in the Neurodynamic group compared to Stretching group. Conclusion. Findings suggest that a neurodynamic sliding technique will increase hamstring flexibility to a greater degree than static hamstring stretching in healthy subjects with SHS. Clinical Relevance. The use of neurodynamic sliding techniques to improve hamstring flexibility in sports may lead to a decreased incidence in injuries; however, this needs to be formally tested.

  15. Acute effects of progressive muscle relaxation on state anxiety and subjective well-being in chronic Bulgarian patients with schizophrenia.

    Science.gov (United States)

    Georgiev, Asen; Probst, Michel; De Hert, Marc; Genova, Valentina; Tonkova, Anastasiya; Vancampfort, Davy

    2012-12-01

    Recently, there has been an interest in the relative effectiveness of progressive muscle relaxation (PMR) within the multidisciplinary treatment of patients with schizophrenia.The present study is aimed at providing evidence on the efficacy of PMR as means of alleviating the state anxiety and psychological distress and a way to increase subjective well-being in chronic patients with schizophrenia. Sixty four schizophrenia patients underwent 2 sessions of PMR. On the third session they were randomly allocated to either the PMR or the reading control condition. The State Anxiety Inventory (SAI) was used to assess state anxiety and the Subjective Exercise Experience Scale (SEES) to assess psychological distress and subjective well-being before and after the third session for both groups. Our data show a significant time by group interaction for the SAI and SEES (Wilks λ=0.58, p<0.001). Effect sizes for PMR were -0.22 (95%CI=-0.73 to 0.19) for state anxiety, -0.96 (95%CI=-0.41 to -1.43) for psychological stress, and +1.01 (95%CI=0.45 to 1.54) for subjective well-being. The present study provides scientific evidence for the utility of PMR in the chronic psychiatric settings for patients with schizophrenia.

  16. Functional significance of extent and timing of muscle activation during double poling on-snow with increasing speed.

    Science.gov (United States)

    Zoppirolli, Chiara; Boccia, Gennaro; Bortolan, Lorenzo; Schena, Federico; Pellegrini, Barbara

    2017-11-01

    To evaluate the level of activation and timing of upper- and lower-body muscles during double poling at different speeds on snow. Nineteen well-trained cross-country skiers volunteered to double pole on a flat snowy track at different speeds (15, 18, 21 km h -1 ). The target speeds could be maintained by the skiers thanks to the use of an audio-pace system in combination with cones spaced equally alongside the track. Only 11 subjects were finally included in the analysis, since their actual speeds, calculated through a photocell system, were within ±0.5 km h -1 from those requested. Cycle and poling durations were measured from the recordings of an accelerometer attached to a wrist, while the pattern and the level of muscle activation were evaluated from electromyographyc signals. Double poling speed did not alter the sequence of muscle activation that started with hip flexors, continued with trunk flexors, shoulder, elbow and trunk extensors and ended with ankle plantar-flexors. However, higher speeds required an increasing involvement of thigh, trunk and shoulder muscles (P < 0.05) as well as an anticipation of their activation before pole plant (P < 0.05). A progressively earlier activation of trunk and lower limb muscles is a coordinative strategy that allows rapid achievement of optimal body posture prior to the exertion of poling phase. Moreover, earlier activation of these muscles as the speed increases provides adequate muscle stiffness in the shoulder and core regions for the acceptance of the poling load.

  17. Human muscle fiber types in power lifters, distance runners and untrained subjects.

    Science.gov (United States)

    Prince, F P; Hikida, R S; Hagerman, F C

    1976-05-06

    Muscle biopsies were taken from the vastus lateralis of 12 males: 5 control subjects, 4 power lifters and 3 distance runners. Three fiber "types" were distinguished by comparing serial sections for alkaline myofibrillar adenosine triphosphatase (ATPase) and succinic dehydrogenase (SDH) activities: 1. high ATPase and low SDH; fast-twitch-glycolytic (FG). 2. High ATPase and high SDH; fast-twitch-oxidative-glycolytic (FOG). 3. Low ATPase and high SDH; slow-twitch-oxidative (SO). In some cases the distinction between the FOG and FG classess was not clear and a group termed "transitional" was employed. A variation in percentage of fiber types and fiber area was found among individuals. The percentage of SO fibers varied from 19.6-60.1% within all 3 groups, with a mean of 40.5%. In the control group approximately 75% of the fibers were oxidative (FOG + SO). The major characteristics of the lifters were a decrease in the percentage of FOG fibers and a hypertrophy of FOG and FG fibers. The distance runners had a high percentage of oxidative fibers with few FG fibers. It is suggested that the fast-twitch fibers are mainly involved in the adaptation of muscle to exercise since the percentage of SO fibers varies greatly among individuals within and between the 3 groups studied.

  18. Muscle stimulation waveform timing patterns for upper and lower leg muscle groups to increase muscular endurance in functional electrical stimulation pedaling using a forward dynamic model.

    Science.gov (United States)

    Hakansson, Nils A; Hull, M L

    2009-09-01

    Functional electrical stimulation (FES) of pedaling provides a means by which individuals with spinal cord injury can obtain cardiorespiratory exercise. However, the early onset of muscle fatigue is a limiting factor in the cardiorespiratory exercise obtained while pedaling an FES ergometer. One objective of this study was to determine muscle excitation timing patterns to increase muscle endurance in FES pedaling for three upper leg muscle groups and to compare these timing patterns to those used in a commercially available FES ergometer. The second objective was to determine excitation timing patterns for a lower leg muscle group in conjunction with the three upper leg muscle groups. The final objective was to determine the mechanical energy contributions of each of the muscle groups to drive the crank. To fulfill these objectives, we developed a forward dynamic simulation of FES pedaling to determine electrical stimulation on and off times that minimize the muscle stress-time integral of the stimulated muscles. The computed electrical stimulation on and off times differed from those utilized by a commercially available FES ergometer and resulted in 17% and 11% decrease in the muscle stress-time integral for the three upper leg muscle groups and four upper and lower leg muscle groups, respectively. Also, the duration of muscle activation by the hamstrings increased by 5% over a crank cycle for the computed stimulation on and off times, and the mechanical energy generated by the hamstrings increased by 20%. The lower leg muscle group did not generate sufficient mechanical energy to reduce the energy contributions of the upper leg muscle groups. The computed stimulation on and off times could prolong FES pedaling, and thereby provide improved cardiorespiratory and muscle training outcomes for individuals with spinal cord injury. Including the lower leg muscle group in FES pedaling could increase cardiorespiratory demand while not affecting the endurance of the

  19. Masticatory and cervical muscle tenderness and pain sensitivity in a remote area in subjects with a temporomandibular disorder and neck disability.

    Science.gov (United States)

    Silveira, Anelise; Armijo-Olivo, Susan; Gadotti, Inae C; Magee, David

    2014-01-01

    To compare the masticatory and cervical muscle tenderness and pain sensitivity in the hand (remote region) between patients with temporomandibular disorders (TMD) and healthy controls. Twenty female subjects were diagnosed with chronic TMD, and 20 were considered healthy. Subjects completed the Neck Disability Index and Limitations of Daily Functions in a TMD questionnaire. Tenderness of the masticatory and cervical muscles and pain sensitivity in the hand were measured using an algometer. Three-way mixed analysis of variance (ANOVA) evaluated differences in muscle tenderness between groups. One-way ANOVA compared pain sensitivity in the hand between groups. Effect sizes were assessed using Cohen guidelines. Significantly increased masticatory and cervical muscle tenderness and pain sensitivity in the hand were found in subjects with TMD when compared with healthy subjects. Moderate to high effect sizes showed the clinical relevance of the findings. The results of this study have highlighted the importance of assessing TMD patients not only in the craniofacial region but also in the neck and other parts of the body. Future studies should focus on testing the effectiveness of treatments addressing the neck and the pain sensitivity in the hand in patients with TMD.

  20. Discrepancies between Skinned Single Muscle Fibres and Whole Thigh Muscle Function Characteristics in Young and Elderly Human Subjects

    OpenAIRE

    Hyunseok Jee; Jae-Young Lim

    2016-01-01

    We aimed to analyse the mechanical properties of skinned single muscle fibres derived from the vastus lateralis (VL) muscle in relation to those of the whole intact thigh muscle and to compare any difference between young and older adults. Sixteen young men (29.25 ? 4.65 years), 11 older men (71.45 ? 2.94 years), 11 young women (29.64 ? 4.88 years), and 7 older women (67.29 ? 1.70 years) were recruited. In vivo analyses were performed for mechanical properties such as isokinetic performance, ...

  1. Moderate exercise increases expression for sensory, adrenergic, and immune genes in chronic fatigue syndrome patients but not in normal subjects.

    Science.gov (United States)

    Light, Alan R; White, Andrea T; Hughen, Ronald W; Light, Kathleen C

    2009-10-01

    Chronic fatigue syndrome (CFS) is characterized by debilitating fatigue, often accompanied by widespread muscle pain that meets criteria for fibromyalgia syndrome (FMS). Symptoms become markedly worse after exercise. Previous studies implicated dysregulation of the sympathetic nervous system (SNS), and immune system (IS) in CFS and FMS. We recently demonstrated that acid sensing ion channel (probably ASIC3), purinergic type 2X receptors (probably P2X4 and P2X5) and the transient receptor potential vanilloid type 1 (TRPV1) are molecular receptors in mouse sensory neurons detecting metabolites that cause acute muscle pain and possibly muscle fatigue. These molecular receptors are found on human leukocytes along with SNS and IS genes. Real-time, quantitative PCR showed that 19 CFS patients had lower expression of beta-2 adrenergic receptors but otherwise did not differ from 16 control subjects before exercise. After a sustained moderate exercise test, CFS patients showed greater increases than control subjects in gene expression for metabolite detecting receptors ASIC3, P2X4, and P2X5, for SNS receptors alpha-2A, beta-1, beta-2, and COMT and IS genes for IL10 and TLR4 lasting from 0.5 to 48 hours (P fatigue, mental fatigue, and pain. These new findings suggest dysregulation of metabolite detecting receptors as well as SNS and IS in CFS and CFS-FMS. Muscle fatigue and pain are major symptoms of CFS. After moderate exercise, CFS and CFS-FMS patients show enhanced gene expression for receptors detecting muscle metabolites and for SNS and IS, which correlate with these symptoms. These findings suggest possible new causes, points for intervention, and objective biomarkers for these disorders.

  2. Improved glucose tolerance after intensive life style intervention occurs without changes in muscle ceramide or triacylglycerol in morbidly obese subjects

    DEFF Research Database (Denmark)

    Helge, J. W.; Stallknecht, B.; Drachmann, Tue

    2011-01-01

    Aim: This study investigated the effect of a 15-week life style intervention (hypocaloric diet and regular exercise) on glucose tolerance, skeletal muscle lipids and muscle metabolic adaptations in 14 female and 9 male morbidly obese subjects (age: 32.5 +/- 2.3 years, BMI: 46.1 +/- 1.9 kg m(-2......)). Method: Before and after the life style intervention an oral glucose tolerance test (OGTT) was performed and a muscle biopsy was obtained in the fasted state. Maximal oxygen uptake was measured by an indirect test. Results: After the intervention body weight was decreased (P...

  3. Skeletal muscle lipid quantification in lean and diabetic subjects using in vivo proton MR spectroscopy

    Directory of Open Access Journals (Sweden)

    Sunil K Valaparla

    2014-03-01

    Full Text Available Purpose: To quantify and compare the intramyocellular (IMCL, extramyocellular (EMCL lipids and total fat fraction in human vastus lateralis muscle between lean and type 2 diabetic (T2DM subjects using long echo time (TE STEAM proton MR spectroscopy (1H-MRS. Methods: 1H-MRS using single voxel (15 × 15 × 15 mm3 stimulated acquisition mode (STEAM was performed in right vastus lateralis m. on 10 lean controls (age: 28.3 ± 3.94 yo, BMI: 24.25 ± 3.20 kg/m2 and 7 type 2 diabetic (age: 54.28 ± 6.42 yo, BMI: 31.34 ± 3.13 kg/m2 subjects with Siemens 3T MRI and a four-channel flex coil. Unsuppressed water spectra (NSA = 16 with TR/TE = 3000/30 ms, TM = 10 ms BW = 2000 Hz, and water-suppressed spectra (NSA = 128 with TR/TE = 3000/270 ms, TM = 10 ms, fixed water suppression BW = 50 Hz were acquired. Spectral intensity ratios of IMCL-CH2, EMCL-CH2 and total lipid (IMCL + EMCL with unsuppressed water signal (W were converted into absolute concentrations expressed in mmol/kg. Fat fraction (100 × F/(W+F was also calculated, where F includes the signal intensities of IMCL and EMCL methylene (CH2n, peaks only.Results: Comparison of IMCL (controls: 11.70 ± 6.7, T2DM: 21.74 ± 10.2, p < 0.01, EMCL (controls: 22.89 ± 18.42, T2DM: 77.21 ± 33.4, p < 0.001 and total lipid (64.35 mmol/kg less in controls, p < 0.001 showed statistical significance using two-tailed student’s t-test. Mean fat fraction (% exhibited considerable inter-individual variability for controls (3.14 ± 2.09; range: 1.34 – 7.04 and T2DM (9.34 ± 2.88; range: 4.15 – 13.67 and deemed significant (p < 0.05. Conclusion: Single voxel STEAM 1H-MRS at long TE provides a robust non-invasive method for characterizing lipids within localized muscle regions, with well-resolved IMCL/EMCL peak separation. Regional lipid estimate and fat fraction in vastus lateralis muscle is significantly different in T2DM compared to normal lean controls.------------------------------Cite this article as

  4. Changes of postural control and muscle activation pattern in response to external perturbations after neck flexor fatigue in young subjects with and without chronic neck pain.

    Science.gov (United States)

    Cheng, Chih-Hsiu; Chien, Andy; Hsu, Wei-Li; Yen, Ling-Wei; Lin, Yang-Hua; Cheng, Hsin-Yi Kathy

    2015-03-01

    Previous studies have identified sensorimotor disturbances and greater fatigability of neck muscles in patients with neck pain. The purpose of this study was to investigate the effect of neck pain and neck flexor fatigue on standing balance following postural perturbations. Twenty patients with chronic neck pain (CNP) (24.7±3.6 year-old) and 20 age-matched asymptomatic subjects (22.1±2.2 year-old) were recruited. Subjects stood barefoot on a force plate and experienced backward perturbations before and after neck flexor fatigue. Center of pressure, electromyography of cervical and lumbar muscles, and head/trunk accelerations were recorded. Two-way ANOVA (pain×fatigue) was used for statistical analysis. CNP group showed larger body sway during quiet standing but not during perturbed standing compared with asymptomatic adults. In both groups, neck flexor fatigue resulted in greater body sway during the quiet standing but smaller body sway during perturbed standing, increased neck muscle activations and decreased lumbar muscle activations, as well as increased time to maximal head acceleration. Disturbed balance control was observed in CNP patients during the quiet standing. However, a rigid strategy was used to minimize the postural sway and to protect the head against backward perturbations in both CNP and asymptomatic young adults after neck flexor fatigue. The results facilitate the understanding of how the subjects with chronic neck pain and with neck muscle fatigue deal with the challenging condition. Further studies are needed to verify if such phenomenon could be changed after the intervention of specific flexor muscle retraining and balance control exercises. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Electrically stimulated resistance training in SCI individuals increases muscle fatigue resistance but not femoral artery size or blood flow.

    Science.gov (United States)

    Sabatier, M J; Stoner, L; Mahoney, E T; Black, C; Elder, C; Dudley, G A; McCully, K

    2006-04-01

    Longitudinal. The purpose of this study was to evaluate the effect of lower extremity resistance training on quadriceps fatigability, femoral artery diameter, and femoral artery blood flow. Academic Institution. Five male chronic spinal cord injury (SCI) individuals (American Spinal Injury Association (ASIA): A complete; C5-T10; 36+/-5 years old) completed 18 weeks of home-based neuromuscular electrical stimulation (NMES) resistance training. Subjects trained the quadriceps muscle group twice a week with four sets of 10 dynamic knee extensions against resistance while in a seated position. All measurements were made before training and after 8, 12, and 18 weeks of training. Ultrasound was used to measure femoral artery diameter and blood flow. Blood flow was measured before and after 5 and 10 min of distal cuff occlusion, and during a 4-min isometric electrical stimulation fatigue protocol. Training resulted in significant increases in weight lifted and muscle mass, as well as a 60% reduction in muscle fatigue (P = 0.001). However, femoral arterial diameter did not increase. The range was 0.44+/-0.03 to 0.46+/-0.05 cm over the four time points (P = 0.70). Resting, reactive hyperemic, and exercise blood flow did not appear to change with training. NMES resistance training improved muscle size and fatigue despite an absence of response in the supplying vasculature. These results suggest that the decreases in arterial caliber and blood flow seen with SCI are not tightly linked to muscle mass and fatigue resistance. In addition, muscle fatigue in SCI patients can be improved without increases in arterial diameter or blood flow capacity.

  6. Calorie restriction increases muscle mitochondrial biogenesis in healthy humans.

    OpenAIRE

    Civitarese, Anthony E.; Stacy Carling; Heilbronn, Leonie K.; Hulver, Mathew H; Barbara Ukropcova; Deutsch, Walter A.; Smith, Steven R.; Eric Ravussin

    2007-01-01

    Editors' Summary Background. Life expectancy (the average life span) greatly increased during the 20th century in most countries, largely due to improved hygiene, nutrition, and health care. One possible approach to further increase human life span is “caloric restriction.” A calorie-restricted diet provides all the nutrients necessary for a healthy life but minimizes the energy (calories) supplied in the diet. This type of diet increases the life span of mice and delays the onset of age-rela...

  7. Basic Training of Student’s Outdoor Club Increases Muscle Mass after Five Weeks of Exercise in Males

    Directory of Open Access Journals (Sweden)

    Novie Salsabila

    2015-03-01

    Full Text Available Background: Aerobic and anaerobic exercises, may lead to increase muscle mass. The aim of this study was to determine the change in muscle mass during basic training of students’ outdoor club. Methods: This was an observational analytic study to college students who joined basic training of students’ outdoor club for 19 weeks. Subjects consisted of 17 male and 15 female students, measured five times consecutively by using Body Fat/Hydration monitor scale, with Bioelectrical Impedance Analysis principle. Data collection was performed five times, from February to July 2012 in Bandung. Statistical analysis was processed using Analysis of Variance (ANOVA. Results: The result in males showed the mean 43.35±3.15 on the initial measurement. The muscle mass further increased significantly after five, ten, fifteen, and nineteen weeks of exercise (43.73±3.18 (p0.05; 38.08±1.67 (p>0.05 ; 38.23±1.52 (p>0.05 ; 38.61±1.52 (p<0.05 vs 37.77±2.00 respectively. Conclusion: Basic training of student’s outdoor club increases muscle mass significantly after five weeks of exercise in males, but not in females

  8. Lumbar and abdominal muscle activity during walking in subjects with chronic low back pain: Support of the ''guarding'' hypothesis?

    NARCIS (Netherlands)

    van der Hulst, M.; Vollenbroek-Hutten, Miriam Marie Rosé; Rietman, Johan Swanik; Hermens, Hermanus J.

    It has been hypothesized that changes in trunk muscle activity in chronic low back pain (CLBP) reflect an underlying “guarding��? mechanism, which will manifest itself as increased superficial abdominal – and lumbar muscle activity. During a functional task like walking, it may be further provoked

  9. Hydrogen peroxide production is not primarily increased in human myotubes established from type 2 diabetic subjects

    DEFF Research Database (Denmark)

    Minet, A D; Gaster, M

    2011-01-01

    Increased oxidative stress and mitochondrial dysfunction have been implicated in the development of insulin resistance in type 2 diabetes. To date, it is unknown whether increased mitochondrial reactive oxygen species (ROS) production in skeletal muscle from patients with type 2 diabetes...

  10. Immediate Effects of Neurodynamic Sliding versus Muscle Stretching on Hamstring Flexibility in Subjects with Short Hamstring Syndrome

    Directory of Open Access Journals (Sweden)

    Yolanda Castellote-Caballero

    2014-01-01

    Full Text Available Background. Hamstring injuries continue to affect active individuals and although inadequate muscle extensibility remains a commonly accepted factor, little is known about the most effective method to improve flexibility. Purpose. To determine if an isolated neurodynamic sciatic sliding technique would improve hamstring flexibility to a greater degree than stretching or a placebo intervention in asymptomatic subjects with short hamstring syndrome (SHS. Study Design. Randomized double-blinded controlled trial. Methods. One hundred and twenty subjects with SHS were randomized to 1 of 3 groups: neurodynamic sliding, hamstring stretching, and placebo control. Each subject’s dominant leg was measured for straight leg raise (SLR range of motion (ROM before and after interventions. Data were analyzed with a 3×2 mixed model ANOVA followed by simple main effects analyses. Results. At the end of the study, more ROM was observed in the Neurodynamic and Stretching groups compared to the Control group and more ROM in the Neurodynamic group compared to Stretching group. Conclusion. Findings suggest that a neurodynamic sliding technique will increase hamstring flexibility to a greater degree than static hamstring stretching in healthy subjects with SHS. Clinical Relevance. The use of neurodynamic sliding techniques to improve hamstring flexibility in sports may lead to a decreased incidence in injuries; however, this needs to be formally tested.

  11. Intermittent stretch training of rabbit plantarflexor muscles increases soleus mass and serial sarcomere number.

    Science.gov (United States)

    De Jaeger, Dominique; Joumaa, Venus; Herzog, Walter

    2015-06-15

    In humans, enhanced joint range of motion is observed after static stretch training and results either from an increased stretch tolerance or from a change in the biomechanical properties of the muscle-tendon unit. We investigated the effects of an intermittent stretch training on muscle biomechanical and structural variables. The left plantarflexors muscles of seven anesthetized New Zealand (NZ) White rabbits were passively and statically stretched three times a week for 4 wk, while the corresponding right muscles were used as nonstretched contralateral controls. Before and after the stretching protocol, passive torque produced by the left plantarflexor muscles as a function of the ankle angle was measured. The left and right plantarflexor muscles were harvested from dead rabbits and used to quantify possible changes in muscle structure. Significant mass and serial sarcomere number increases were observed in the stretched soleus but not in the plantaris or medial gastrocnemius. This difference in adaptation between the plantarflexors is thought to be the result of their different fiber type composition and pennation angles. Neither titin isoform nor collagen amount was modified in the stretched compared with the control soleus muscle. Passive torque developed during ankle dorsiflexion was not modified after the stretch training on average, but was decreased in five of the seven experimental rabbits. Thus, an intermittent stretching program similar to those used in humans can produce a change in the muscle structure of NZ White rabbits, which was associated in some rabbits with a change in the biomechanical properties of the muscle-tendon unit. Copyright © 2015 the American Physiological Society.

  12. Local overexpression of the myostatin propeptide increases glucose transporter expression and enhances skeletal muscle glucose disposal.

    Science.gov (United States)

    Cleasby, M E; Jarmin, S; Eilers, W; Elashry, M; Andersen, D K; Dickson, G; Foster, K

    2014-04-01

    Insulin resistance (IR) in skeletal muscle is a prerequisite for type 2 diabetes and is often associated with obesity. IR also develops alongside muscle atrophy in older individuals in sarcopenic obesity. The molecular defects that underpin this syndrome are not well characterized, and there is no licensed treatment. Deletion of the transforming growth factor-β family member myostatin, or sequestration of the active peptide by overexpression of the myostatin propeptide/latency-associated peptide (ProMyo) results in both muscle hypertrophy and reduced obesity and IR. We aimed to establish whether local myostatin inhibition would have a paracrine/autocrine effect to enhance glucose disposal beyond that simply generated by increased muscle mass, and the mechanisms involved. We directly injected adeno-associated virus expressing ProMyo in right tibialis cranialis/extensor digitorum longus muscles of rats and saline in left muscles and compared the effects after 17 days. Both test muscles were increased in size (by 7 and 11%) and showed increased radiolabeled 2-deoxyglucose uptake (26 and 47%) and glycogen storage (28 and 41%) per unit mass during an intraperitoneal glucose tolerance test. This was likely mediated through increased membrane protein levels of GLUT1 (19% higher) and GLUT4 (63% higher). Interestingly, phosphorylation of phosphoinositol 3-kinase signaling intermediates and AMP-activated kinase was slightly decreased, possibly because of reduced expression of insulin-like growth factor-I in these muscles. Thus, myostatin inhibition has direct effects to enhance glucose disposal in muscle beyond that expected of hypertrophy alone, and this approach may offer potential for the therapy of IR syndromes.

  13. Rapid increases in training load affects markers of skeletal muscle damage and mechanical performance

    DEFF Research Database (Denmark)

    Kamandulis, Sigitas; Snieckus, Audrius; Venckunas, Tomas

    2012-01-01

    a program involving a rapid stepwise increase in the number of jumps, drop height, and squat depth, and the addition of weight. Concentric, isometric maximal voluntary contraction (MVC), and stimulated knee extension torque were measured before and 10 min after each session. Muscle soreness and plasma...... creatine kinase activity were assessed after each session. Steep increments in stretch-shortening exercise load in sessions 4 and 7 amplified the postexercise decrease in stimulated muscle torque and slightly increased muscle soreness but had a minimal effect on the recovery of MVC and stimulated torque......The aim of the present study was to monitor the changes in indirect markers of muscle damage during 3 weeks (nine training sessions) of stretch-shortening (drop jump) exercise with constant load alternated with steep increases in load. Physically active men (n = 9, mean age 19.1 years) performed...

  14. Immediate Effects of Combining Local Techniques in the Craniomandibular Area and Hamstring Muscle Stretching in Subjects with Temporomandibular Disorders: A Randomized Controlled Study.

    Science.gov (United States)

    Rodriguez-Blanco, Cleofás; Cocera-Morata, Francisco Miguel; Heredia-Rizo, Alberto Marcos; Ricard, François; Almazán-Campos, Ginés; Oliva-Pascual-Vaca, Ángel

    2015-08-01

    To assess the immediate effects on vertical mouth opening, orofacial mechanosensitivity, and lumbar and suboccipital mobility after adding a myofascial induction technique to a multimodal protocol in subjects with temporomandibular disorders (TMD). A randomized and double-blind controlled trial was carried out. University-based physical therapy research clinic. Sixty subjects (35±11.22 years) with TMD, and restricted mobility of the mandibular condyles and the first cervical vertebrae, were recruited and randomized to either a control group (CG) (n=30) or an experimental group (EG) (n=30). The CG underwent a neuromuscular technique over the masseter muscles and passive hamstring muscle stretching. A suboccipital muscle inhibition technique was added to this protocol in the EG. Primary measurements were made of vertical mouth opening and pressure pain threshold of the masseter muscles. Secondary outcome measures included pressure algometry of the trigeminal nerve, suboccipital range of motion, and lumbar spine mobility, assessed with the sit-and-reach (SAR) test and lumbar forward bending. All evaluations were collected at baseline and immediately after intervention. In the intragroup comparison, the EG observed an increase in suboccipital flexion (p0.05). The inclusion of a myofascial induction maneuver in a protocol combining local (neuromuscular treatment) and distal techniques (hamstring stretching) in subjects with TMD has no impact on improving mouth opening, suboccipital and lumbar mobility, and orofacial sensitivity to mechanical pressure.

  15. Rosmarinic Acid, a Rosemary Extract Polyphenol, Increases Skeletal Muscle Cell Glucose Uptake and Activates AMPK.

    Science.gov (United States)

    Vlavcheski, Filip; Naimi, Madina; Murphy, Brennan; Hudlicky, Tomas; Tsiani, Evangelia

    2017-10-07

    Skeletal muscle is a major insulin-target tissue and plays an important role in glucose homeostasis. Impaired insulin action in muscles leads to insulin resistance and type 2 diabetes mellitus. 5' AMP-activated kinase (AMPK) is an energy sensor, its activation increases glucose uptake in skeletal muscle and AMPK activators have been viewed as a targeted approach in combating insulin resistance. We previously reported AMPK activation and increased muscle glucose uptake by rosemary extract (RE). In the present study, we examined the effects and the mechanism of action of rosmarinic acid (RA), a major RE constituent, in L6 rat muscle cells. RA (5.0 µM) increased glucose uptake (186 ± 4.17% of control, p < 0.001) to levels comparable to maximum insulin (204 ± 10.73% of control, p < 0.001) and metformin (202 ± 14.37% of control, p < 0.001). Akt phosphorylation was not affected by RA, while AMPK phosphorylation was increased. The RA-stimulated glucose uptake was inhibited by the AMPK inhibitor compound C and was not affected by wortmannin, an inhibitor of phosphoinositide 3-kinase (PI3K). The current study shows an effect of RA to increase muscle glucose uptake and AMPK phosphorylation. RA deserves further study as it shows potential to be used as an agent to regulate glucose homeostasis.

  16. Rosmarinic Acid, a Rosemary Extract Polyphenol, Increases Skeletal Muscle Cell Glucose Uptake and Activates AMPK

    Directory of Open Access Journals (Sweden)

    Filip Vlavcheski

    2017-10-01

    Full Text Available Skeletal muscle is a major insulin-target tissue and plays an important role in glucose homeostasis. Impaired insulin action in muscles leads to insulin resistance and type 2 diabetes mellitus. 5′ AMP-activated kinase (AMPK is an energy sensor, its activation increases glucose uptake in skeletal muscle and AMPK activators have been viewed as a targeted approach in combating insulin resistance. We previously reported AMPK activation and increased muscle glucose uptake by rosemary extract (RE. In the present study, we examined the effects and the mechanism of action of rosmarinic acid (RA, a major RE constituent, in L6 rat muscle cells. RA (5.0 µM increased glucose uptake (186 ± 4.17% of control, p < 0.001 to levels comparable to maximum insulin (204 ± 10.73% of control, p < 0.001 and metformin (202 ± 14.37% of control, p < 0.001. Akt phosphorylation was not affected by RA, while AMPK phosphorylation was increased. The RA-stimulated glucose uptake was inhibited by the AMPK inhibitor compound C and was not affected by wortmannin, an inhibitor of phosphoinositide 3-kinase (PI3K. The current study shows an effect of RA to increase muscle glucose uptake and AMPK phosphorylation. RA deserves further study as it shows potential to be used as an agent to regulate glucose homeostasis.

  17. Increased autophagy and apoptosis contribute to muscle atrophy in a myotonic dystrophy type 1 Drosophila model

    Directory of Open Access Journals (Sweden)

    Ariadna Bargiela

    2015-07-01

    Full Text Available Muscle mass wasting is one of the most debilitating symptoms of myotonic dystrophy type 1 (DM1 disease, ultimately leading to immobility, respiratory defects, dysarthria, dysphagia and death in advanced stages of the disease. In order to study the molecular mechanisms leading to the degenerative loss of adult muscle tissue in DM1, we generated an inducible Drosophila model of expanded CTG trinucleotide repeat toxicity that resembles an adult-onset form of the disease. Heat-shock induced expression of 480 CUG repeats in adult flies resulted in a reduction in the area of the indirect flight muscles. In these model flies, reduction of muscle area was concomitant with increased apoptosis and autophagy. Inhibition of apoptosis or autophagy mediated by the overexpression of DIAP1, mTOR (also known as Tor or muscleblind, or by RNA interference (RNAi-mediated silencing of autophagy regulatory genes, achieved a rescue of the muscle-loss phenotype. In fact, mTOR overexpression rescued muscle size to a size comparable to that in control flies. These results were validated in skeletal muscle biopsies from DM1 patients in which we found downregulated autophagy and apoptosis repressor genes, and also in DM1 myoblasts where we found increased autophagy. These findings provide new insights into the signaling pathways involved in DM1 disease pathogenesis.

  18. Niacin supplementation increases the number of oxidative type I fibers in skeletal muscle of growing pigs

    Science.gov (United States)

    2013-01-01

    Background A recent study showed that niacin supplementation counteracts the obesity-induced muscle fiber switching from oxidative type I to glycolytic type II and increases the number of type I fibers in skeletal muscle of obese Zucker rats. These effects were likely mediated by the induction of key regulators of fiber transition, PGC-1α and PGC-1β, leading to muscle fiber switching and up-regulation of genes involved in mitochondrial fatty acid import and oxidation, citrate cycle, oxidative phosphorylation, mitochondrial biogenesis. The aim of the present study was to investigate whether niacin supplementation causes type II to type I muscle and changes the metabolic phenotype of skeletal muscles in growing pigs. Results 25 male, 11 wk old crossbred pigs (Danzucht x Pietrain) with an average body weight of 32.8 ± 1.3 (mean ± SD) kg were randomly allocated to two groups of 12 (control group) and 13 pigs (niacin group) which were fed either a control diet or a diet supplemented with 750 mg niacin/kg diet. After 3 wk, the percentage number of type I fibers in three different muscles (M. longissismus dorsi, M. quadriceps femoris, M. gastrocnemius) was greater in the niacin group and the percentage number of type II fibers was lower in the niacin group than in the control group (P niacin group than in the control group (P niacin supplementation induces type II to type I muscle fiber switching, and thereby an oxidative metabolic phenotype of skeletal muscle in pigs. Given that oxidative muscle types tend to develop dark, firm and dry pork in response to intense physical activity and/or high psychological stress levels preslaughter, a niacin-induced change in the muscle´s fiber type distribution may influence meat quality of pigs. PMID:24010567

  19. Relations between muscle endurance and subjectively reported fatigue, walking capacity, and participation in mildly affected adolescents with cerebral palsy.

    Science.gov (United States)

    Eken, Maaike M; Houdijk, Han; Doorenbosch, Caroline A M; Kiezebrink, Francisca E M; van Bennekom, Coen A M; Harlaar, Jaap; Dallmeijer, Annet J

    2016-08-01

    To investigate the relation between muscle endurance and subjectively reported fatigue, walking capacity, and participation in mildly affected adolescents with cerebral palsy (CP) and peers with typical development. In this case-control study, knee extensor muscle endurance was estimated from individual load-endurance curves as the load corresponding to a 15-repetition maximum in 17 adolescents with spastic CP (six males, 11 females; age 12-19y) and 18 adolescents with typical development (eight males, 10 females; age 13-19y). Questionnaires were used to assess subjectively reported fatigue (Pediatric Quality of Life Inventory Multidimensional Fatigue Scale) and participation (Life-Habits questionnaire). Walking capacity was assessed using the 6-minute walk test. Relations were determined using multiple regression analyses. Muscle endurance related significantly to subjectively reported fatigue and walking capacity in adolescents with CP, while no relations were found for adolescents with typical development (subjectively reported fatigue: regression coefficient β [95% confidence intervals] for CP=23.72 [6.26 to 41.18], for controls=2.72 [-10.26 to 15.69]; walking capacity β for CP=125m [-87 to 337], for controls=2m [-86 to 89]). The 15-repetition maximum did not relate to participation in adolescents with CP. Subjectively reported fatigue and reduced walking capacity in adolescents with CP are partly caused by lower muscle endurance of knee extensors. Training of muscle endurance might contribute to reducing the experience of fatigue and improving walking capacity. Reduced muscle endurance seems to have no effect on participation. © 2016 Mac Keith Press.

  20. Divergent muscle sympathetic responses to dynamic leg exercise in heart failure and age-matched healthy subjects.

    Science.gov (United States)

    Notarius, Catherine F; Millar, Philip J; Murai, Hisayoshi; Morris, Beverley L; Marzolini, Susan; Oh, Paul; Floras, John S

    2015-02-01

    People with diminished ventricular contraction who develop heart failure have higher sympathetic nerve firing rates at rest compared with healthy individuals of a similar age and this is associated with less exercise capacity. During handgrip exercise, sympathetic nerve activity to muscle is higher in patients with heart failure but the response to leg exercise is unknown because its recording requires stillness. We measured sympathetic activity from one leg while the other leg cycled at a moderate level and observed a decrease in nerve firing rate in healthy subjects but an increase in subjects with heart failure. Because these nerves release noradrenaline, which can restrict muscle blood flow, this observation helps explain the limited exercise capacity of patients with heart failure. Lower nerve traffic during exercise was associated with greater peak oxygen uptake, suggesting that if exercise training attenuated sympathetic outflow functional capacity in heart failure would improve. The reflex fibular muscle sympathetic nerve (MSNA) response to dynamic handgrip exercise is elicited at a lower threshold in heart failure with reduced ejection fraction (HFrEF). The present aim was to test the hypothesis that the contralateral MSNA response to mild to moderate dynamic one-legged exercise is augmented in HFrEF relative to age- and sex-matched controls. Heart rate (HR), blood pressure and MSNA were recorded in 16 patients with HFrEF (left ventricular ejection fraction = 31 ± 2%; age 62 ± 3 years, mean ± SE) and 13 healthy control subjects (56 ± 2 years) before and during 2 min of upright one-legged unloaded cycling followed by 2 min at 50% of peak oxygen uptake (V̇O2,peak). Resting HR and blood pressure were similar between groups whereas MSNA burst frequency was higher (50.0 ± 2.0 vs. 42.3 ± 2.7 bursts min(-1), P = 0.03) and V̇O2,peak lower (18.0 ± 2.0 vs. 32.6 ± 2.8 ml kg(-1) min(-1), P Exercise increased HR (P group difference (P = 0.1). MSNA burst

  1. Prevention of denaturation of freshwater crayfish muscle subjected to different freeze-thaw cycles by gelatin hydrolysate.

    Science.gov (United States)

    Yasemi, Mehran

    2017-11-01

    The cryoprotective effect of gelatin hydrolysates from the skin of beluga sturgeon (Huso huso) on freshwater crayfish (Astacus leptodactylus) muscle subjected to different freeze-thaw cycles was investigated. Untreated muscle was particularly susceptible to quality loss as indicated by the formation of secondary lipid oxidation products and the loss in sulfhydryl groups and Ca2+-ATPase activity. Hydrolysate produced using flavourzyme which was mainly consisted of oligopeptides as the main fraction as well as small fraction of polypeptides could lower the denaturation of crayfish myosin heavy chain when compared to the control. In addition, lipid oxidation in treated muscle was impeded to some extent. Peptides with smaller or longer chain length than those in flavourzyme hydrolysate although exhibited antioxidant activity, but were less effective in maintaining the muscle quality during storage. Thus, the potential of flavourzyme hydrolysate as the alternative cryoprotectant might be employed during crustacean processing. Copyright © 2017. Published by Elsevier Ltd.

  2. p53 increases caspase-6 expression and activation in muscle tissue expressing mutant huntingtin

    DEFF Research Database (Denmark)

    Ehrnhoefer, Dagmar E; Skotte, Niels H; Ladha, Safia

    2014-01-01

    a role in the peripheral phenotypes, such as muscle wasting observed in HD. We assessed skeletal muscle tissue from HD patients and well-characterized mouse models of HD. Cleavage of the caspase-6 specific substrate lamin A is significantly increased in skeletal muscle obtained from HD patients as well...... as in muscle tissues from two different HD mouse models. p53, a transcriptional activator of caspase-6, is upregulated in neuronal cells and tissues expressing mutant huntingtin. Activation of p53 leads to a dramatic increase in levels of caspase-6 mRNA, caspase-6 activity and cleavage of lamin A. Using mouse......-6 expression and activation is exacerbated in cells and tissues of both neuronal and peripheral origin expressing mutant huntingtin (Htt). These findings suggest that the presence of the mutant Htt protein enhances p53 activity and lowers the apoptotic threshold, which activates caspase-6...

  3. Hypermetabolism of compensatory laryngeal muscles in unilateral vocal cord palsy: comparison study between speech and silence with normal subjects by co-registered PET-CT fusion images

    Energy Technology Data Exchange (ETDEWEB)

    Pai, Moon Sun; Kim, Hyon Kyong; Kim, Han Su; Chung, Sung Min [College of Medicine, Ewha Womans University, Seoul (Korea, Republic of)

    2005-07-01

    There are a few case reports on asymmetric vocal cord uptake on FDG-PET in patients with unilateral vocal cord paralysis, which could be a potential pitfall in the interpretation of FDG-PET images. We evaluated the metabolic activity of laryngeal muscles of patients with unilateral vocal cord paralysis in comparison to normal controls during both speech and silence. Eleven patients with iatrogenic unilateral vocal cord palsy(thyroidectomy 7, lung cancer = 1, others = 3) and 12 normal controls underwent FDG-PET with usual protocol. They were divided into two groups respectively; one group read books aloud for 20 minutes (phonation group) and the other kept silence (non-phonation groups) after FDG injection. Recent neck CT scan were co-registered with FDG-PET to produce PET-CT fusion images to elaborate small laryngeal muscles. In patients with unilateral vocal cord palsy, contralateral non-paralyzed vocal cord showed increased FDG uptake, more intense with phonation group (SUV =5.88, n =5) than non-phonation group (SUV =2.33, n =6) --mainly on thyroarytenoid muscle. Normal control subjects showed symmetric mildly increased FDG uptake (SUV=1.92, n=6) only in phonation group, which was significantly low against patient groups and was localized in lateral cricoarytenoid muscle. Hypermetabolism of contralateral thyroarytenoid muscle in patients with unilateral vocal cord paralysis could be encountered during FDG-PET imaging even with keeping silence. Phonation during FDG-PET study enhance FDG uptake on different laryngeal muscles between unilateral vocal cord paralysis and normal subjects.

  4. Tumor growth increases neuroinflammation, fatigue and depressive-like behavior prior to alterations in muscle function.

    Science.gov (United States)

    Norden, Diana M; Bicer, Sabahattin; Clark, Yvonne; Jing, Runfeng; Henry, Christopher J; Wold, Loren E; Reiser, Peter J; Godbout, Jonathan P; McCarthy, Donna O

    2015-01-01

    Cancer patients frequently suffer from fatigue, a complex syndrome associated with loss of muscle mass, weakness, and depressed mood. Cancer-related fatigue (CRF) can be present at the time of diagnosis, during treatment, and persists for years after treatment. CRF negatively influences quality of life, limits functional independence, and is associated with decreased survival in patients with incurable disease. Currently there are no effective treatments to reduce CRF. The aim of this study was to use a mouse model of tumor growth and discriminate between two main components of fatigue: loss of muscle mass/function and altered mood/motivation. Here we show that tumor growth increased fatigue- and depressive-like behaviors, and reduced body and muscle mass. Decreased voluntary wheel running activity (VWRA) and increased depressive-like behavior in the forced swim and sucrose preference tests were evident in tumor-bearing mice within the first two weeks of tumor growth and preceded the loss of body and muscle mass. At three weeks, tumor-bearing mice had reduced grip strength but this was not associated with altered expression of myosin isoforms or impaired contractile properties of muscles. These increases in fatigue and depressive-like behaviors were paralleled by increased expression of IL-1β mRNA in the cortex and hippocampus. Minocycline administration reduced tumor-induced expression of IL-1β in the brain, reduced depressive-like behavior, and improved grip strength without altering muscle mass. Taken together, these results indicate that neuroinflammation and depressed mood, rather than muscle wasting, contribute to decreased voluntary activity and precede major changes in muscle contractile properties with tumor growth. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Exercise Training-Induced Adaptations Associated with Increases in Skeletal Muscle Glycogen Content

    Science.gov (United States)

    Manabe, Yasuko; Gollisch, Katja S.C.; Holton, Laura; Kim, Young–Bum; Brandauer, Josef; Fujii, Nobuharu L.; Hirshman, Michael F.; Goodyear, Laurie J.

    2012-01-01

    Chronic exercise training results in numerous skeletal muscle adaptations, including increases in insulin sensitivity and glycogen content. To understand the mechanism for increased muscle glycogen, we studied the effects of exercise training on glycogen regulatory proteins in rat skeletal muscle. Female Sprague Dawley rats performed voluntary wheel running for 1, 4, or 7 weeks. After 7 weeks of training, insulin-stimulated glucose uptake was increased in epitrochlearis muscle. Compared to sedentary control rats, muscle glycogen did not change after 1 week of training, but increased significantly after 4 and 7 weeks. The increases in muscle glycogen were accompanied by elevated glycogen synthase activity and protein expression. To assess the regulation of glycogen synthase, we examined its major activator, protein phosphatase 1 (PP1), and its major deactivator, glycogen synthase kinase 3 (GSK3). Consistent with glycogen synthase activity, PP1 activity was unchanged after 1 week of training but significantly increased after 4 and 7 weeks of training. Protein expression of RGL(GM), another regulatory PP1 subunit, significantly decreased after 4 and 7 weeks of training. Unlike PP1, GSK3 phosphorylation did not follow the pattern of glycogen synthase activity. The ~40% decrease in GSK-3α phosphorylation after 1 week of exercise training persisted until 7 weeks and may function as a negative feedback to elevated glycogen. Our findings suggest that exercise training-induced increases in muscle glycogen content could be regulated by multiple mechanisms including enhanced insulin sensitivity, glycogen synthase expression, allosteric activation of glycogen synthase and PP1activity. PMID:23206309

  6. Atrophy, fibrosis, and increased PAX7-positive cells in pharyngeal muscles of oculopharyngeal muscular dystrophy patients.

    Science.gov (United States)

    Gidaro, Teresa; Negroni, Elisa; Perié, Sophie; Mirabella, Massimiliano; Lainé, Jeanne; Lacau St Guily, Jean; Butler-Browne, Gillian; Mouly, Vincent; Trollet, Capucine

    2013-03-01

    Oculopharyngeal muscular dystrophy (OPMD) is a late-onset autosomal dominant inherited dystrophy caused by an abnormal trinucleotide repeat expansion in the poly(A)-binding-protein-nuclear 1 (PABPN1) gene. Primary muscular targets of OPMD are the eyelid elevator and pharyngeal muscles, including the cricopharyngeal muscle (CPM), the progressive involution of which leads to ptosis and dysphagia, respectively. To understand the consequences of PABPN1 polyalanine expansion in OPMD, we studied muscle biopsies from 14 OPMD patients, 3 inclusion body myositis patients, and 9 healthy controls. In OPMD patient CPM (n = 6), there were typical dystrophic features with extensive endomysial fibrosis and marked atrophy of myosin heavy-chain IIa fibers. There were more PAX7-positive cells in all CPM versus other muscles (n = 5, control; n = 3, inclusion body myositis), and they were more numerous in OPMD CPM versus control normal CPM without any sign of muscle regeneration. Intranuclear inclusions were present in all OPMD muscles but unaffected OPMD patient muscles (i.e. sternocleidomastoid, quadriceps, or deltoid; n = 14) did not show evidence of fibrosis, atrophy, or increased PAX7-positive cell numbers. These results suggest that the specific involvement of CPM in OPMD might be caused by failure of the regenerative response with dysfunction of PAX7-positive cells and exacerbated fibrosis that does not correlate with the presence of PABPN1 inclusions.

  7. Increasing NAD synthesis in muscle via nicotinamide phosphoribosyltransferase is not sufficient to promote oxidative metabolism.

    Science.gov (United States)

    Frederick, David W; Davis, James G; Dávila, Antonio; Agarwal, Beamon; Michan, Shaday; Puchowicz, Michelle A; Nakamaru-Ogiso, Eiko; Baur, Joseph A

    2015-01-16

    The NAD biosynthetic precursors nicotinamide mononucleotide and nicotinamide riboside are reported to confer resistance to metabolic defects induced by high fat feeding in part by promoting oxidative metabolism in skeletal muscle. Similar effects are obtained by germ line deletion of major NAD-consuming enzymes, suggesting that the bioavailability of NAD is limiting for maximal oxidative capacity. However, because of their systemic nature, the degree to which these interventions exert cell- or tissue-autonomous effects is unclear. Here, we report a tissue-specific approach to increase NAD biosynthesis only in muscle by overexpressing nicotinamide phosphoribosyltransferase, the rate-limiting enzyme in the salvage pathway that converts nicotinamide to NAD (mNAMPT mice). These mice display a ∼50% increase in skeletal muscle NAD levels, comparable with the effects of dietary NAD precursors, exercise regimens, or loss of poly(ADP-ribose) polymerases yet surprisingly do not exhibit changes in muscle mitochondrial biogenesis or mitochondrial function and are equally susceptible to the metabolic consequences of high fat feeding. We further report that chronic elevation of muscle NAD in vivo does not perturb the NAD/NADH redox ratio. These studies reveal for the first time the metabolic effects of tissue-specific increases in NAD synthesis and suggest that critical sites of action for supplemental NAD precursors reside outside of the heart and skeletal muscle. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. Prior AICAR stimulation increases insulin sensitivity in mouse skeletal muscle in an AMPK-dependent manner

    DEFF Research Database (Denmark)

    Kjøbsted, Rasmus; Treebak, Jonas Thue; Fentz, Joachim

    2015-01-01

    Acute exercise increases glucose uptake in skeletal muscle by an insulin-independent mechanism. In the period after exercise insulin sensitivity to increase glucose uptake is enhanced. The molecular mechanisms underpinning this phenomenon are poorly understood, but appear to involve an increased ...

  9. Is increase in bone mineral content caused by increase in skeletal muscle mass/strength in adult patients with GH-treated GH deficiency? A systematic literature analysis

    DEFF Research Database (Denmark)

    Klefter, O.; Feldt-Rasmussen, U.

    2009-01-01

    to a muscle modulating effect, and if treatment with GH would primarily increase muscle mass and strength with a secondary increase in BMD/BMC, thus supporting the present physiological concept that mass and strength of bones are mainly determined by dynamic loads from the skeletal muscles. METHOD: We...... performed a systematic literature analysis, including 51 clinical trials published between 1996 and 2008, which had studied the development in muscle mass, muscle strength, BMD, and/or BMC in GH-treated adult GHD patients. RESULTS: GH therapy had an anabolic effect on skeletal muscle. The largest increase...... studied both muscle and bone variables concomitantly. No trials studied the relationship between the changes in muscle and bone measurements. CONCLUSION: Although in vitro studies have shown that GH has a direct effect on bone remodeling, present physiological concepts and the results of clinical trials...

  10. Sex and muscle structural lipids in obese subjects - an impact on insulin action?

    DEFF Research Database (Denmark)

    Haugaard, SB; Vaag, A.; Høy, Carl-Erik

    2008-01-01

    resistance, despite the fact that an android fat distribution is detrimental to insulin action. The increased extramyocellular fat mass of obese women may act in a paracrine manner such that its release of free FA and cytokines may hamper in situ desaturation and elongation of FA in skeletal muscle...... distribution, nine non-diabetic obese men with a typical android fat distribution and 12 (seven females) lean age matched healthy controls (body mass index 34.6 +/- 1.0 kg m(-2), 36.5 +/- 1.2 and 22.5 +/- 0.5; age 47 +/- 2 years, 51 +/- 3 and 49 +/- 2). RESULTS: Obese women displayed decreased LCPUFA n-3...... to controls (Ps android...

  11. Assessment of the strength of the trunk and upper limb muscles in stroke subjects with portable dynamometry: a literature review

    OpenAIRE

    Martins, Júlia Caetano; Teixeira-Salmela, Luci Fuscaldi; Aguiar, Larissa Tavares; Souza, Lucas Araújo Castro e; Lara, Eliza Maria; Faria, Christina Danielli Coelho de Morais

    2015-01-01

    Introduction Clinical measurements of strength in stroke subjects are usually performed and portable dynamometers are one of the most employed instruments. Objective To verify the standardization procedures of the methods used to assess the strength of the trunk and upper limb muscles with portable dynamometers in stroke subjects, as well as to assess the psychometric properties which were already investigated. Materials and methods An extensive search was performed on the MEDLINE, SciELO, LI...

  12. Sensitivity of subject-specific models to Hill muscle-tendon model parameters in simulations of gait

    NARCIS (Netherlands)

    Carbone, V.; Krogt, M.M. van der; Koopman, H.F.J.M.; Verdonschot, N.J.

    2016-01-01

    Subject-specific musculoskeletal (MS) models of the lower extremity are essential for applications such as predicting the effects of orthopedic surgery. We performed an extensive sensitivity analysis to assess the effects of potential errors in Hill muscle-tendon (MT) model parameters for each of

  13. Three distinct cell populations express extracellular matrix proteins and increase in number during skeletal muscle fibrosis.

    Science.gov (United States)

    Chapman, Mark A; Mukund, Kavitha; Subramaniam, Shankar; Brenner, David; Lieber, Richard L

    2017-02-01

    Tissue extracellular matrix (ECM) provides structural support and creates unique environments for resident cells (Bateman JF, Boot-Handford RP, Lamandé SR. Nat Rev Genet 10: 173-183, 2009; Kjaer M. Physiol Rev 84: 649-98, 2004). However, the identities of cells responsible for creating specific ECM components have not been determined. In striated muscle, the identity of these cells becomes important in disease when ECM changes result in fibrosis and subsequent increased tissue stiffness and dysfunction. Here we describe a novel approach to isolate and identify cells that maintain the ECM in both healthy and fibrotic muscle. Using a collagen I reporter mouse, we show that there are three distinct cell populations that express collagen I in both healthy and fibrotic skeletal muscle. Interestingly, the number of collagen I-expressing cells in all three cell populations increases proportionally in fibrotic muscle, indicating that all cell types participate in the fibrosis process. Furthermore, while some profibrotic ECM and ECM-associated genes are significantly upregulated in fibrotic muscle, the fibrillar collagen gene expression profile is not qualitatively altered. This suggests that muscle fibrosis in this model results from an increased number of collagen I-expressing cells and not the initiation of a specific fibrotic collagen gene expression program. Finally, in fibrotic muscle, we show that these collagen I-expressing cell populations differentially express distinct ECM proteins-fibroblasts express the fibrillar components of ECM, fibro/adipogenic progenitors cells differentially express basal laminar proteins, and skeletal muscle progenitor cells differentially express genes important for the satellite cell. Copyright © 2017 the American Physiological Society.

  14. Stimulation of shank muscles during functional electrical stimulation cycling increases ankle excursion in individuals with spinal cord injury.

    Science.gov (United States)

    Fornusek, Ché; Davis, Glen M; Baek, Ilhun

    2012-11-01

    To investigate the effect of shank muscle stimulation on ankle joint excursion during passive and functional electrical stimulation (FES) leg cycling. Within-subject comparisons. Laboratory setting. Well-trained FES cyclists (N=7) with chronic spinal cord injuries. Two experimental sessions were performed on an isokinetic FES cycle ergometer with a pedal boot that allowed the ankle to plantarflex and dorsiflex during cycling. During the first session, the optimal stimulation timings to induce plantarflexion and dorsiflexion were investigated by systematically altering the stimulation angles of the shank muscles (tibialis anterior [TA] and triceps surae [TS]). During the second session, TA and TS stimulation was included with standard FES cycling (quadriceps, hamstrings, and gluteals) for 6 subjects. Ankle, knee, and hip movements were analyzed using 2-dimensional video. The ankle excursions during passive cycling were 19°±6°. TA and TS stimulation increased ankle joint excursion up to 33°±10° and 27°±7°, respectively. Compared with passive cycling, ankle joint excursion was not significantly increased during standard FES cycling (24°±7°). TA and TS stimulation significantly increased the ankle excursion when applied during standard FES cycling (41°±4°). Freeing the ankle joint to rotate during FES cycling was found to be safe. The combination of shank muscle stimulation and repetitive ankle joint movement may be beneficial for improving ankle flexibility and leg conditioning. Further research is required to test and design ankle supports that might maximize the benefits of shank muscle activation. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  15. Increased proinflammatory responses from asthmatic human airway smooth muscle cells in response to rhinovirus infection

    Directory of Open Access Journals (Sweden)

    King Nicholas JC

    2006-05-01

    Full Text Available Abstract Background Exacerbations of asthma are associated with viral respiratory tract infections, of which rhinoviruses (RV are the predominant virus type. Airway smooth muscle is important in asthma pathogenesis, however little is known about the potential interaction of RV and human airway smooth muscle cells (HASM. We hypothesised that rhinovirus induction of inflammatory cytokine release from airway smooth muscle is augmented and differentially regulated in asthmatic compared to normal HASM cells. Methods HASM cells, isolated from either asthmatic or non-asthmatic subjects, were infected with rhinovirus. Cytokine production was assayed by ELISA, ICAM-1 cell surface expression was assessed by FACS, and the transcription regulation of IL-6 was measured by luciferase activity. Results RV-induced IL-6 release was significantly greater in HASM cells derived from asthmatic subjects compared to non-asthmatic subjects. This response was RV specific, as 5% serum- induced IL-6 release was not different in the two cell types. Whilst serum stimulated IL-8 production in cells from both subject groups, RV induced IL-8 production in only asthmatic derived HASM cells. The transcriptional induction of IL-6 was differentially regulated via C/EBP in the asthmatic and NF-κB + AP-1 in the non-asthmatic HASM cells. Conclusion This study demonstrates augmentation and differential transcriptional regulation of RV specific innate immune response in HASM cells derived from asthmatic and non-asthmatics, and may give valuable insight into the mechanisms of RV-induced asthma exacerbations.

  16. Increasing muscle strength and mass of thigh in elderly people with the hybrid-training method of electrical stimulation and volitional contraction.

    Science.gov (United States)

    Takano, Yoshio; Haneda, Yoshihiro; Maeda, Takashi; Sakai, Yutaka; Matsuse, Hiroo; Kawaguchi, Takumi; Tagawa, Yoshihiko; Shiba, Naoto

    2010-05-01

    The "Hybrid training" (HYBT) method utilizing combined electrical stimulation and voluntary muscle contraction has been developed as a muscle training method. It has already been shown that the method is technically sound and clinically effective in healthy young subjects. The purpose of this study was to investigate the effect of the HYBT method on the knee extensor strength considering safety for elderly people. Twenty subjects were randomly divided into two groups: the HYBT group and the weight machine training (WMT) group. All the subjects performed knee flexion and extension for 19 min per session, twice a week for 12 weeks. At the baseline and after the training, the subjects' maximal isometric torque of knee extension and cross-sectional area (CSA) of quadriceps femoris muscle were measured. The subjects completed the study without adverse effects. The knee extension torque significantly increased in both groups (39% in HYBT group and 42% in WMT group, P muscle strength and mass, and that this method is as effective as the WMT. In addition, unlike the WMT, the HYBT device, which is portable and not large in size, is so easy to handle that it can be placed at the bedside. Therefore, the HYBT has potential to become a safe, effective method of muscle training for elderly people.

  17. Collagen peptide supplementation in combination with resistance training improves body composition and increases muscle strength in elderly sarcopenic men: a randomised controlled trial.

    Science.gov (United States)

    Zdzieblik, Denise; Oesser, Steffen; Baumstark, Manfred W; Gollhofer, Albert; König, Daniel

    2015-10-28

    Protein supplementation in combination with resistance training may increase muscle mass and muscle strength in elderly subjects. The objective of this study was to assess the influence of post-exercise protein supplementation with collagen peptides v. placebo on muscle mass and muscle function following resistance training in elderly subjects with sarcopenia. A total of fifty-three male subjects (72·2 (sd 4·68) years) with sarcopenia (class I or II) completed this randomised double-blind placebo-controlled study. All the participants underwent a 12-week guided resistance training programme (three sessions per week) and were supplemented with either collagen peptides (treatment group (TG)) (15 g/d) or silica as placebo (placebo group (PG)). Fat-free mass (FFM), fat mass (FM) and bone mass (BM) were measured before and after the intervention using dual-energy X-ray absorptiometry. Isokinetic quadriceps strength (IQS) of the right leg was determined and sensory motor control (SMC) was investigated by a standardised one-leg stabilisation test. Following the training programme, all the subjects showed significantly higher (Ptraining further improved body composition by increasing FFM, muscle strength and the loss in FM.

  18. Lower limb muscle activation during the sit-to-stand task in subjects who have had a stroke.

    Science.gov (United States)

    Prudente, Cecília; Rodrigues-de-Paula, Fátima; Faria, Christina D C M

    2013-08-01

    The aim of this study was to compare electromyographic activities between and within the paretic and nonparetic lower limb muscles during the sit-to-stand (STS) task in subjects with hemiparesis as a result of stroke. This is a cross-sectional study. All monitored muscles of both lower limbs remained active during most of the sit-to-stand task; the muscles were activated before the seat-off and reached the maximum peak of electromyographic activity after the seat-off (P limb, the nonparetic limb exhibited earlier activation of the hamstrings (P muscles of the nonparetic lower limb (P ≥ 0.053), whereas the tibialis anterior of the paretic lower limb was activated before the hamstring and the soleus (P ≤ 0.015). These results illustrate that muscle activation of both limbs during the sit-to-stand task was impaired but in a higher level in the paretic side. Neuromuscular coordination abnormalities were observed in both lower limbs. The paretic limb was unable to recruit the muscles at the proper time and to achieve the amplitude for executing the sit-to-stand task, whereas significant compensations occurred on the nonparetic side.

  19. Abnormal epigenetic changes during differentiation of human skeletal muscle stem cells from obese subjects

    NARCIS (Netherlands)

    Davegardh, C.; Broholm, C.; Perfilyev, A.; Henriksen, T.; Garcia-Calzon, S.; Peijs, L.; Hansen, N.S.; Volkov, P.; Kjobsted, R.; Wojtaszewski, J.F.; Pedersen, M.; Pedersen, B.K.; Ballak, D.B.; Dinarello, C.A.; Heinhuis, B.; Joosten, L.A.B.; Nilsson, E.; Vaag, A.; Scheele, C.; Ling, C.

    2017-01-01

    BACKGROUND: Human skeletal muscle stem cells are important for muscle regeneration. However, the combined genome-wide DNA methylation and expression changes taking place during adult myogenesis have not been described in detail and novel myogenic factors may be discovered. Additionally, obesity is

  20. Comparison of muscles activity of abled bodied and amputee subjects for around shoulder movement.

    Science.gov (United States)

    Kaur, Amanpreet; Agarwal, Ravinder; Kumar, Amod

    2016-05-12

    Worldwide, about 56% of the amputees are upper limb amputees. This research deals a method with two-channel surface electromyogram (SEMG) signal recorded from around shoulder to estimate the changes in muscle activity in non-amputee and the residual limb of trans humeral amputees with different movements of arm. Identification of different muscles activity of near shoulder amputee and non-amputee persons. SEMG signal were acquired during three distinct exercises from three-selected muscles location around shoulder. The participants were asked to move their dominant arm from an assigned position to record their muscles activity recorded with change in position. Results shows the muscles activity in scalene is more than the other muscles like pectoralis and infraspinatus with the same shoulder motion. In addition, STFT (Short-Time Fourier Transform) spectrogram with window length of 256 samples at maximum of 512 frequency bins using hamming window has used to identify the signal for the maximum muscles activity with best resolution in spectrum plot. The results suggest that one can use this analysis for making a suitable device for around shoulder prosthetic users based on muscles activation of amputee persons.

  1. Phenylephrine increases near-infrared spectroscopy determined muscle oxygenation in men

    DEFF Research Database (Denmark)

    Sørensen, H.; Thomsen, J. H.; Meyer, A. S. Ps

    2017-01-01

    Phenylephrine increases mean arterial pressure (MAP) by enhanced total peripheral resistance (TPR) but near-infrared spectroscopy (NIRS) determined muscle oxygenation (SmO2) increases. We addressed that apparent paradox during supine rest and head-up tilt (HUT). Variables were determined ± phenyl...

  2. Subchronic exposure to diisocyanates increases guinea pig tracheal smooth muscle responses to acetylcholine.

    Science.gov (United States)

    Marek, W; Potthast, J; Marczynski, B; Mensing, T; Baur, X

    1999-01-01

    In order to study the threshold concentrations of isocyanates (IC) for induction of lung disorders, constrictive responses of tracheal smooth muscles to acetylcholine (ACH) in guinea pigs with and without diisocyanate [toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI) and diphenylmethane diisocyanate (MDI)] exposure were investigated. An IC-induced increase in smooth muscle responsiveness was studied by measuring cumulative ACH dose responses (10(-10) to 10(-4) M ACH). Basal ACH dose-response curves, measured twice in intervals of 1 h using tracheal preparations of 11 guinea pigs previously not exposed to IC, were reproducible. Subchronic in vivo exposures to TDI, HDI, and MDI atmospheres of 10 and 20 parts per billion (ppb) on 5 consecutive days led to significantly (p < 0.05) increased ACH responsiveness of tracheal smooth muscle, whereas concentrations of 2.5 and 5 ppb were not effective. Exposure to HDI atmospheres of 10 ppb for 1, 2, 4, or 8 weeks resulted in a time-dependent increase in ACH responses (p < 0.05) of guinea pig tracheal smooth muscle. Increased tracheal muscle responses to ACH were transient since tracheal preparations from animals exposed to 10 and 20 ppb MDI for 4 weeks and with an exposure-free interval of 8 weeks before preparation did not show enlarged ACH responses, which were present in preparations at the end of the exposure period (p < 0.05). Exposure to low IC concentrations as present in workplaces cause increased ACH responsiveness of guinea pig tracheal smooth muscle. The increased responsiveness of the airways seems to be largely reversible, since normal responses were found after 8 weeks of IC avoidance. Reversibility of IC-induced airway hyperresponsiveness is of great occupational and preventive medical importance. Workers with acquired airway hyperresponsiveness might escape lung damage if the changes are detected in an early stage before alterations in lung function are in a chronic stage.

  3. Two-week inhalation of budesonide increases muscle Na,K ATPase content but not endurance in response to terbutaline in men

    DEFF Research Database (Denmark)

    Hostrup, Morten; Jessen, Søren; Onslev, Johan

    2017-01-01

    While chronic systemic administration of glucocorticoids increases muscle Na+,K+ ATPase content, such effect is unexplored after therapeutic inhalation. We investigated the effect of therapeutic inhalation of the glucocorticoid budesonide on Na+,K+ ATPase content of skeletal muscle in men. Ten...... healthy trained subjects, aged 23 ± 4 years (mean ± 95% CI), participated in the study. Before and after 2 weeks of daily inhalation of budesonide (1.6 mg/day), a biopsy was taken from the vastus lateralis muscle for measurement of Na+,K+ ATPase content and blood samples were drawn for determination....... The present observations show that therapeutic inhalation of glucocorticoids increases muscle Na+,K+ ATPase content, but does not enhance high-intensity cycling endurance in response to terbutaline....

  4. Two-week inhalation of budesonide increases muscle Na,K ATPase content but not endurance in response to terbutaline in men

    DEFF Research Database (Denmark)

    Nielsen, Morten Hostrup; Onslev, Johan; Jessen, Søren Kaare

    2017-01-01

    While chronic systemic administration of glucocorticoids increases muscle Na+ ,K+ ATPase content, such effect is unexplored after therapeutic inhalation. We investigated the effect of therapeutic inhalation of the glucocorticoid budesonide on Na+ ,K+ ATPase content of skeletal muscle in men. Ten...... healthy trained subjects, aged 23 ± 4 years (mean ± 95% CI), participated in the study. Before and after 2 weeks of daily inhalation of budesonide (1.6 mg/day), a biopsy was taken from the vastus lateralis muscle for measurement of Na+ ,K+ ATPase content and blood samples were drawn for determination....... The present observations show that therapeutic inhalation of glucocorticoids increases muscle Na+ ,K+ ATPase content, but does not enhance high-intensity cycling endurance in response to terbutaline....

  5. Blood flow after contraction and cuff occlusion is reduced in subjects with muscle soreness after eccentric exercise

    DEFF Research Database (Denmark)

    Souza-Silva, Eduardo; Wittrup Christensen, Steffan; Hirata, Rogerio Pessoto

    2017-01-01

    Purpose: Delayed onset muscle soreness (DOMS) occur within 1-2 days after eccentric exercise but the mechanism mediating hypersensitivity is unclear. This study hypothesized that eccentric exercise reduces the blood flow response following muscle contractions and cuff occlusion, which may result ...... that eccentric contractions decreased vessel diameter, impaired the blood flow response and promoted hyperalgesia. Thus, the results suggest that the blood flow reduction may be involved in the increased pain response after eccentric exercise....

  6. Combined intermittent hypoxia and surface muscle electrostimulation as a method to increase peripheral blood progenitor cell concentration

    Directory of Open Access Journals (Sweden)

    Azqueta Carmen

    2009-10-01

    Full Text Available Abstract Background Our goal was to determine whether short-term intermittent hypoxia exposure, at a level well tolerated by healthy humans and previously shown by our group to increase EPO and erythropoiesis, could mobilize hematopoietic stem cells (HSC and increase their presence in peripheral circulation. Methods Four healthy male subjects were subjected to three different protocols: one with only a hypoxic stimulus (OH, another with a hypoxic stimulus plus muscle electrostimulation (HME and the third with only muscle electrostimulation (OME. Intermittent hypobaric hypoxia exposure consisted of only three sessions of three hours at barometric pressure 540 hPa (equivalent to an altitude of 5000 m for three consecutive days, whereas muscular electrostimulation was performed in two separate periods of 25 min in each session. Blood samples were obtained from an antecubital vein on three consecutive days immediately before the experiment and 24 h, 48 h, 4 days and 7 days after the last day of hypoxic exposure. Results There was a clear increase in the number of circulating CD34+ cells after combined hypobaric hypoxia and muscular electrostimulation. This response was not observed after the isolated application of the same stimuli. Conclusion Our results open a new application field for hypobaric systems as a way to increase efficiency in peripheral HSC collection.

  7. Do the rotator cuff tendons of young athletic subjects hypertrophy in response to increased loading demands?

    Science.gov (United States)

    Milgrom, Charles; Moran, Daniel S; Safran, Ori; Finsestone, Aharon S

    2012-11-01

    The rotator cuff is composed of muscle and tendon units. Although muscle has been shown to adapt to mechanical loads, the response of human tendon is not well defined. We hypothesized that increased loading demands on the rotator cuff of young trainees would cause an adaptive muscle response but not an adaptive hypertrophic tendon response. The hypertrophic response of the rotator cuff tendon, shoulder strength, aerobic fitness, and the lean body weight of 70 young male recruits were studied before and after a 1-year course of elite infantry training. Shoulder strength was assessed by the maximum number of pull-ups done and the rotator cuff thickness by ultrasound measurement of the supraspinatus thickness. Aerobic physical fitness was assessed by maximum oxygen consumption (Vo(2) max). Lean body weight was measured by skin-fold thickness. The mean number of pull-ups done increased from 17.5 to 21.7 (P = .01), but the supraspinatus thickness at the beginning of training (6.1 mm) was unchanged at the end of the training. Vo(2) max increased from 57 to 64 mL/kg/min (P = .0001). Lean body weight increased from 58.3 to 64.7 kg (P = .0001). As a result of increased loading, the strength of the rotator cuff muscles of young trainees increased, but by the parameter of hypertrophy, no evidence was found of a parallel adaptive response of the rotator cuff tendon. Copyright © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

  8. Is increase in bone mineral content caused by increase in skeletal muscle mass/strength in adult patients with GH-treated GH deficiency?

    DEFF Research Database (Denmark)

    Klefter, Oliver; Feldt-Rasmussen, Ulla

    2009-01-01

    OBJECTIVE: Adult patients with GH deficiency (GHD) are characterized by a reduced muscle mass, but also reduced bone mineral density (BMD) and content (BMC), which have been ascribed to GHD per se. The aim of this study was to investigate if changes in BMD/BMC in adult GHD patients could be due...... to a muscle modulating effect, and if treatment with GH would primarily increase muscle mass and strength with a secondary increase in BMD/BMC, thus supporting the present physiological concept that mass and strength of bones are mainly determined by dynamic loads from the skeletal muscles. METHOD: We...... performed a systematic literature analysis, including 51 clinical trials published between 1996 and 2008, which had studied the development in muscle mass, muscle strength, BMD, and/or BMC in GH-treated adult GHD patients. RESULTS: GH therapy had an anabolic effect on skeletal muscle. The largest increase...

  9. Ursolic acid increases skeletal muscle and brown fat and decreases diet-induced obesity, glucose intolerance and fatty liver disease.

    Directory of Open Access Journals (Sweden)

    Steven D Kunkel

    Full Text Available Skeletal muscle Akt activity stimulates muscle growth and imparts resistance to obesity, glucose intolerance and fatty liver disease. We recently found that ursolic acid increases skeletal muscle Akt activity and stimulates muscle growth in non-obese mice. Here, we tested the hypothesis that ursolic acid might increase skeletal muscle Akt activity in a mouse model of diet-induced obesity. We studied mice that consumed a high fat diet lacking or containing ursolic acid. In skeletal muscle, ursolic acid increased Akt activity, as well as downstream mRNAs that promote glucose utilization (hexokinase-II, blood vessel recruitment (Vegfa and autocrine/paracrine IGF-I signaling (Igf1. As a result, ursolic acid increased skeletal muscle mass, fast and slow muscle fiber size, grip strength and exercise capacity. Interestingly, ursolic acid also increased brown fat, a tissue that shares developmental origins with skeletal muscle. Consistent with increased skeletal muscle and brown fat, ursolic acid increased energy expenditure, leading to reduced obesity, improved glucose tolerance and decreased hepatic steatosis. These data support a model in which ursolic acid reduces obesity, glucose intolerance and fatty liver disease by increasing skeletal muscle and brown fat, and suggest ursolic acid as a potential therapeutic approach for obesity and obesity-related illness.

  10. BACK MUSCLES STRENGTH DEVELOPMENT BY MEANS OF INCREASE AND DECREASE OF EFFORT LOAD DURING GIANT SETS IN BODYBUILDING FOR MASSES

    Directory of Open Access Journals (Sweden)

    TIMNEA OLIVIA

    2013-01-01

    Full Text Available Abstract The aim of the study is to highlight methodological issues on the back muscle strength development by combining methodological procedures in masses bodybuilding.Methods. The study was conducted in three stages over a period of two months (March-April 2011, performing three workouts per week, monitoring the effective use of strength exercises to develop back muscles in the same muscle area by means of giant sets during workouts. In this context, we conducted a case study in "Tonik Fitness Club" in Bucharest, applied to two athletes of 28 and 34 years old. We recorded subjects’ evolutions during the training session, using statistical and mathematical method and graphical representation method.Results. The study content highlights the training programs depending on muscle zone and the specific methodological aspects, the weekly training program per muscle groups, the stages of study carrying out, the test and control trials applied in terms of anthropometric measurements and of back muscle strength development, and the application of the methodical procedure of effort load increase and decrease within the giant sets in a training micro-cycle.Discussion. The study focused on the training programs over two months, monitoring statistically the development of back muscle strength through the application of the procedure of effort load increase and decrease during giant sets in bodybuilding for masses. From the analysis of training programs content we noticed that three giant sets of exercises were used, performed in four series; each exercise within the giant sets was applied by means of the procedure of increasing and decreasing effort load. Study results emphasize the anthropometric measurement results: the study subjects have the age mean of 24.75, with a size of 175.2 cm and a weight of 83.75 kg at initial testing and a decrease by 2.12 kg in final testing. Regarding the chest perimeter, the inspiration is averaging 89.5 in initial

  11. Subjectivity

    Directory of Open Access Journals (Sweden)

    Jesús Vega Encabo

    2015-11-01

    Full Text Available In this paper, I claim that subjectivity is a way of being that is constituted through a set of practices in which the self is subject to the dangers of fictionalizing and plotting her life and self-image. I examine some ways of becoming subject through narratives and through theatrical performance before others. Through these practices, a real and active subjectivity is revealed, capable of self-knowledge and self-transformation. 

  12. Reliability of MR-Based Volumetric 3-D Analysis of Pelvic Muscles among Subjects with Low Back with Leg Pain and Healthy Volunteers.

    Directory of Open Access Journals (Sweden)

    Elżbieta Skorupska

    Full Text Available Lately, the diagnostic value of magnetic resonance imaging, Lasègue sign and classic neurological signs have been considered not accurate enough to distinguish the radicular from non-radicular low back with leg pain (LBLP and a calculation of the symptomatic side muscle volume has been indicated as a probable valuable marker. However, only the multifidus muscle volume has been calculated so far. The main objective of the study was to verify whether LBLP subjects presented symptomatic side pelvic muscle atrophy compared to healthy volunteers. The second aim was to assess the inter-rater reliability of 3-D manual method for segmenting and measuring the volume of the gluteus maximus, gluteus medius, gluteus minimus and piriformis muscles in both LBLP patients and healthy subjects.Two independent raters analyzed MR images of LBLP and healthy subjects towards muscle volume of four pelvic muscles, i.e. the piriformis, gluteus minimus, gluteus medius and gluteus maximus. For both sides, the MR images of the muscles without adipose tissue infiltration were manually segmented in 3-D medical images.Symptomatic muscle atrophy was confirmed in only over 50% of LBLP subjects (gluteus maximus (p<0.001, gluteus minimus (p<0.01 and piriformis (p<0.05. The ICC values indicated that the inter-rater reproducibility was greater than 0.90 for all measurements (LBLP and healthy subjects, except for the measurement of the right gluteus medius muscle in LBLP patients, which was equal to 0.848.More than 50% of LBLP subjects presented symptomatic gluteus maximus, gluteus minimus and piriformis muscle atrophy. 3-D manual segmentation reliably measured muscle volume in all the measured pelvic muscles in both healthy and LBLP subjects. To answer the question of what kind of muscle atrophy is indicative of radicular or non-radicular pain further studies are required.

  13. Increased IGF-IEc expression and mechano-growth factor production in intestinal muscle of fibrostenotic Crohn's disease and smooth muscle hypertrophy.

    Science.gov (United States)

    Li, Chao; Vu, Kent; Hazelgrove, Krystina; Kuemmerle, John F

    2015-12-01

    The igf1 gene is alternatively spliced as IGF-IEa and IGF-IEc variants in humans. In fibrostenotic Crohn's disease, the fibrogenic cytokine TGF-β1 induces IGF-IEa expression and IGF-I production in intestinal smooth muscle and results in muscle hyperplasia and collagen I production that contribute to stricture formation. Mechano-growth factor (MGF) derived from IGF-IEc induces skeletal and cardiac muscle hypertrophy following stress. We hypothesized that increased IGF-IEc expression and MGF production mediated smooth muscle hypertrophy also characteristic of fibrostenotic Crohn's disease. IGF-IEc transcripts and MGF protein were increased in muscle cells isolated from fibrostenotic intestine under regulation by endogenous TGF-β1. Erk5 and MEF2C were phosphorylated in vivo in fibrostenotic muscle; both were phosphorylated and colocalized to nucleus in response to synthetic MGF in vitro. Smooth muscle-specific protein expression of α-smooth muscle actin, γ-smooth muscle actin, and smoothelin was increased in affected intestine. Erk5 inhibition or MEF2C siRNA blocked smooth muscle-specific gene expression and hypertrophy induced by synthetic MGF. Conditioned media of cultured fibrostenotic muscle induced muscle hypertrophy that was inhibited by immunoneutralization of endogenous MGF or pro-IGF-IEc. The results indicate that TGF-β1-dependent IGF-IEc expression and MGF production in patients with fibrostenotic Crohn's disease regulates smooth muscle cell hypertrophy a critical factor that contributes to intestinal stricture formation. Copyright © 2015 the American Physiological Society.

  14. Correlation between cervical flexor muscle thickness and craniocervical flexion torque in healthy subjects.

    Science.gov (United States)

    Ishida, Hiroshi; Suehiro, Tadanobu; Watanabe, Susumu

    2018-01-01

    The purpose of this study was to clarify the relationship between the size of the cervical flexor muscles and craniocervical (CC) flexion torque. Thirty-eight healthy men participated in this study. Thickness of the deep cervical flexor (DCF) and sternocleidomastoid (SM) muscles were measured using ultrasonography. Maximal isometric CC flexion torque was measured using dynamometry. The DCF and SM muscle thickness and CC flexion torque were normalized relative to body weight. Correlations between normalized muscle thickness and normalized CC flexion torque were determined. A significant positive correlation was observed between normalized DCF muscle thickness and normalized CC flexion torque (r = 0.361, P = 0.028), whereas there was no significant correlation between normalized SM muscle thickness and normalized CC flexion torque (r = 0.233, P = 0.166). DCF muscle thickness appears to have potential clinical application in the performance of CC flexion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Effects of abdominal drawing-in during prone hip extension on the muscle activities of the hamstring, gluteus maximus, and lumbar erector spinae in subjects with lumbar hyperlordosis

    Science.gov (United States)

    Kim, Tae-Woo; Kim, Yong-Wook

    2015-01-01

    [Purpose] The purpose of this study was to compare the effects of an abdominal drawing-in maneuver (ADIM), measured using a pressure bio-feedback unit, on the activities of the hamstring, gluteus maximus, and erector spinae muscles during prone hip extension. [Subjects and Methods] Thirty healthy adult subjects (14 male, 16 female), were recruited. Subjects’ lumbar lordosis and pelvic tilt angles were measured, and based on the results, the subjects were divided into two groups: a hyperlordotic lumbar angle (HLLA) group (n=15) and a normal lordotic lumbar angle (NLLA) group (n=15). The muscle activities of the hamstring and gluteus maximus, and of the erector spinae on the right side of the body, were recorded using surface electromyography. [Results] When performing ADIM with prone hip extension, the muscle activity of the gluteus maximus of the HLLA group significantly improved compared with that the NLLA group. [Conclusion] This study demonstrated that ADIM with prone hip extension was more effective at eliciting gluteus maximus activity in the HLLA group than in the NLLA group. Therefore, ADIM with prone hip extension may be useful for increasing the gluteus maximus activity of individuals with lumbar hyperlordosis. PMID:25729173

  16. Insulin increases phosphorylation of mitochondrial proteins in human skeletal muscle in vivo

    DEFF Research Database (Denmark)

    Zhao, Xiaolu; Bak, Steffen; Pedersen, Andreas James Thestrup

    2014-01-01

    There is increasing evidence that multiple proteins involved in key regulatory processes in mitochondria are phosphorylated in mammalian tissues. Insulin regulates glucose metabolism by phosphorylation-dependent signaling and has been shown to stimulate ATP synthesis in human skeletal muscle. Here......, we investigated the effect of insulin on the phosphorylation of mitochondrial proteins in human skeletal muscle in vivo. Using a combination of TiO2 phosphopeptide-enrichment, HILIC fractionation, and LC−MS/MS, we compared the phosphoproteomes of isolated mitochondria from skeletal muscle samples...... obtained from healthy individuals before and after 4 h of insulin infusion. In total, we identified 207 phosphorylation sites in 95 mitochondrial proteins. Of these phosphorylation sites, 45% were identified in both basal and insulin-stimulated samples. Insulin caused a 2-fold increase in the number...

  17. Insulin does not stimulate muscle protein synthesis during increased plasma branched-chain amino acids alone but still decreases whole body proteolysis in humans.

    Science.gov (United States)

    Everman, Sarah; Meyer, Christian; Tran, Lee; Hoffman, Nyssa; Carroll, Chad C; Dedmon, William L; Katsanos, Christos S

    2016-10-01

    Insulin stimulates muscle protein synthesis when the levels of total amino acids, or at least the essential amino acids, are at or above their postabsorptive concentrations. Among the essential amino acids, branched-chain amino acids (BCAA) have the primary role in stimulating muscle protein synthesis and are commonly sought alone to stimulate muscle protein synthesis in humans. Fourteen healthy young subjects were studied before and after insulin infusion to examine whether insulin stimulates muscle protein synthesis in relation to the availability of BCAA alone. One half of the subjects were studied in the presence of postabsorptive BCAA concentrations (control) and the other half in the presence of increased plasma BCAA (BCAA). Compared with that prior to the initiation of the insulin infusion, fractional synthesis rate of muscle protein (%/h) did not change (P > 0.05) during insulin in either the control (0.04 ± 0.01 vs 0.05 ± 0.01) or the BCAA (0.05 ± 0.02 vs. 0.05 ± 0.01) experiments. Insulin decreased (P BCAA (0.89 ± 0.07 vs 0.61 ± 0.03) experiments, but the change was not different between the two experiments (P > 0.05). In conclusion, insulin does not stimulate muscle protein synthesis in the presence of increased circulating levels of plasma BCAA alone. Insulin's suppressive effect on proteolysis is observed independently of the levels of circulating plasma BCAA. Copyright © 2016 the American Physiological Society.

  18. More gain less pain: balance control learning shifts the activation patterns of leg and neck muscles and increases muscular parsimony.

    Science.gov (United States)

    Iodice, Pierpaolo; Cesinaro, Stefano; Romani, Gian Luca; Pezzulo, Giovanni

    2015-07-01

    Athletes such as skaters or surfers maintain their balance on very unstable platforms. Remarkably, the most skilled athletes seem to execute these feats almost effortlessly. However, the dynamics that lead to the acquisition of a defined and efficient postural strategy are incompletely known. To understand the posture reorganization process due to learning and expertise, we trained twelve participants in a demanding balance/posture maintenance task for 4 months and measured their muscular activity before and after a (predictable) disturbance cued by an auditory signal. The balance training determined significant delays in the latency of participants' muscular activity: from largely anticipatory muscular activity (prior to training) to a mixed anticipatory-compensatory control strategy (after training). After training, the onset of activation was delayed for all muscles, and the sequence of activation systematically reflected the muscle position in the body from top to bottom: neck/upper body muscles were recruited first and in an anticipatory fashion, whereas leg muscles were recruited after the disturbance onset, producing compensatory adjustments. The resulting control strategy includes a mixture of anticipatory and compensatory postural adjustments, with a systematic sequence of muscular activation reflecting the different demands of neck and leg muscles. Our results suggest that subjects learned the precise timing of the disturbance onset and used this information to deploy postural adjustments just-in-time and to transfer at least part of the control of posture from anticipatory to less-demanding feedback-based strategies. In turn, this strategy shift increases the cost-efficiency of muscular activity, which is a key signature of skilled performance.

  19. Reliability of MR-Based Volumetric 3-D Analysis of Pelvic Muscles among Subjects with Low Back with Leg Pain and Healthy Volunteers.

    Science.gov (United States)

    Skorupska, Elżbieta; Keczmer, Przemysław; Łochowski, Rafał M; Tomal, Paulina; Rychlik, Michał; Samborski, Włodzimierz

    2016-01-01

    Lately, the diagnostic value of magnetic resonance imaging, Lasègue sign and classic neurological signs have been considered not accurate enough to distinguish the radicular from non-radicular low back with leg pain (LBLP) and a calculation of the symptomatic side muscle volume has been indicated as a probable valuable marker. However, only the multifidus muscle volume has been calculated so far. The main objective of the study was to verify whether LBLP subjects presented symptomatic side pelvic muscle atrophy compared to healthy volunteers. The second aim was to assess the inter-rater reliability of 3-D manual method for segmenting and measuring the volume of the gluteus maximus, gluteus medius, gluteus minimus and piriformis muscles in both LBLP patients and healthy subjects. Two independent raters analyzed MR images of LBLP and healthy subjects towards muscle volume of four pelvic muscles, i.e. the piriformis, gluteus minimus, gluteus medius and gluteus maximus. For both sides, the MR images of the muscles without adipose tissue infiltration were manually segmented in 3-D medical images. Symptomatic muscle atrophy was confirmed in only over 50% of LBLP subjects (gluteus maximus (ppelvic muscles in both healthy and LBLP subjects. To answer the question of what kind of muscle atrophy is indicative of radicular or non-radicular pain further studies are required.

  20. Effects of strength training with blood flow restriction on torque, muscle activation and local muscular endurance in healthy subjects

    Directory of Open Access Journals (Sweden)

    JBC Sousa

    2016-12-01

    Full Text Available The present study aimed to analyse the effects of six weeks of strength training (ST, with and without blood flow restriction (BFR, on torque, muscle activation, and local muscular endurance (LME of the knee extensors. Thirty-seven healthy young individuals were divided into four groups: high intensity (HI, low intensity with BFR (LI+BFR, high intensity and low intensity + BFR (COMB, and low intensity (LI. Torque, muscle activation and LME were evaluated before the test and at the 2nd, 4th and 6th weeks after exercise. All groups had increased torque, muscle activation and LME (p<0.05 after the intervention, but the effect size and magnitude were greater in the HI, LI+BFR and COMB groups. In conclusion, the groups with BFR (LI+BFR and COMB produced magnitudes of muscle activation, torque and LME similar to those of the HI group.

  1. Vinegar Consumption Increases Insulin-Stimulated Glucose Uptake by the Forearm Muscle in Humans with Type 2 Diabetes.

    Science.gov (United States)

    Mitrou, Panayota; Petsiou, Eleni; Papakonstantinou, Emilia; Maratou, Eirini; Lambadiari, Vaia; Dimitriadis, Panayiotis; Spanoudi, Filio; Raptis, Sotirios A; Dimitriadis, George

    2015-01-01

    Vinegar has been shown to have a glucose-lowering effect in patients with glucose abnormalities. However, the mechanisms of this effect are still obscure. The aim of this randomised, crossover study was to investigate the effect of vinegar on glucose metabolism in muscle which is the most important tissue for insulin-stimulated glucose disposal. Eleven subjects with DM2 consumed vinegar or placebo (at random order on two separate days, a week apart), before a mixed meal. Plasma glucose, insulin, triglycerides, nonesterified fatty acids (NEFA), and glycerol were measured preprandially and at 30-60 min for 300 min postprandially from the radial artery and from a forearm vein. Muscle blood flow was measured with strain-gauge plethysmography. Glucose uptake was calculated as the arteriovenous difference of glucose multiplied by blood flow. Vinegar compared to placebo (1) increased forearm glucose uptake (p = 0.0357), (2) decreased plasma glucose (p = 0.0279), insulin (p = 0.0457), and triglycerides (p = 0.0439), and (3) did not change NEFA and glycerol. In DM2 vinegar reduces postprandial hyperglycaemia, hyperinsulinaemia, and hypertriglyceridaemia without affecting lipolysis. Vinegar's effect on carbohydrate metabolism may be partly accounted for by an increase in glucose uptake, demonstrating an improvement in insulin action in skeletal muscle. This trial is registered with Clinicaltrials.gov NCT02309424.

  2. Vinegar Consumption Increases Insulin-Stimulated Glucose Uptake by the Forearm Muscle in Humans with Type 2 Diabetes

    Directory of Open Access Journals (Sweden)

    Panayota Mitrou

    2015-01-01

    Full Text Available Background and Aims. Vinegar has been shown to have a glucose-lowering effect in patients with glucose abnormalities. However, the mechanisms of this effect are still obscure. The aim of this randomised, crossover study was to investigate the effect of vinegar on glucose metabolism in muscle which is the most important tissue for insulin-stimulated glucose disposal. Materials and Methods. Eleven subjects with DM2 consumed vinegar or placebo (at random order on two separate days, a week apart, before a mixed meal. Plasma glucose, insulin, triglycerides, nonesterified fatty acids (NEFA, and glycerol were measured preprandially and at 30–60 min for 300 min postprandially from the radial artery and from a forearm vein. Muscle blood flow was measured with strain-gauge plethysmography. Glucose uptake was calculated as the arteriovenous difference of glucose multiplied by blood flow. Results. Vinegar compared to placebo (1 increased forearm glucose uptake (p=0.0357, (2 decreased plasma glucose (p=0.0279, insulin (p=0.0457, and triglycerides (p=0.0439, and (3 did not change NEFA and glycerol. Conclusions. In DM2 vinegar reduces postprandial hyperglycaemia, hyperinsulinaemia, and hypertriglyceridaemia without affecting lipolysis. Vinegar’s effect on carbohydrate metabolism may be partly accounted for by an increase in glucose uptake, demonstrating an improvement in insulin action in skeletal muscle. This trial is registered with Clinicaltrials.gov NCT02309424.

  3. Botulinum toxin injection causes hyper-reflexia and increased muscle stiffness of the triceps surae muscle in the rat

    DEFF Research Database (Denmark)

    Pingel, Jessica; Wienecke, Jacob; Lorentzen, Jakob

    2016-01-01

    and attached to a muscle puller. The resistance of the muscle to stretches of different amplitudes and velocities was systematically investigated. Reflex mediated torque was normalized to the maximal muscle force (Mmax) evoked by supramaximal stimulation of the tibial nerve. Botulinum toxin injection caused......Botulinum toxin is used to diminish spasticity and reduce the risk of development of contractures. Here, we investigated changes in muscle stiffness caused by reflex activity or elastic muscle properties following botulinum toxin injection in the triceps surae muscle in rats. Forty-four rats...... received injection of botulinum toxin in the left triceps surae muscle. Control measurements were performed on the non-injected contralateral side in all rats. Acute experiments were performed 1, 2, 4 and 8 weeks following injection. The triceps surae muscle was dissected free, the Achilles tendon was cut...

  4. Spinal loads and trunk muscles forces during level walking - A combined in vivo and in silico study on six subjects.

    Science.gov (United States)

    Arshad, Rizwan; Angelini, Lorenza; Zander, Thomas; Di Puccio, Francesca; El-Rich, Marwan; Schmidt, Hendrik

    2017-08-26

    During level walking, lumbar spine is subjected to cyclic movements and intricate loading of the spinal discs and trunk musculature. This study aimed to estimate the spinal loads (T12-S1) and trunk muscles forces during a complete gait cycle. Six men, 24-33years walk barefoot at self-selected speed (4-5km/h). 3D kinematics and ground reaction forces were recorded using a motion capturing system and two force plates, implemented in an inverse dynamic musculoskeletal model to predict the spinal loads and trunk muscles forces. Additionally, the sensitivity of the intra-abdominal pressure and lumbar segment rotational stiffness was investigated. Peak spinal loads and trunk muscle forces were between the gait instances of heel strike and toe off. In L4-L5 segment, sensitivity analysis showed that average peak compressive, antero-posterior and medio-lateral shear forces were 130-179%, 2-15% and 1-6%, with max standard deviation (±STD) of 40%, 6% and 3% of the body weight. Average peak global muscles forces were 24-55% (longissimus thoracis), 11-23% (iliocostalis thoracis), 12-16% (external oblique), 17-25% (internal oblique) and 0-8% (rectus abdominus) of body weight whereas, the average peak local muscles forces were 11-19% (longissimus lumborum), 14-31% (iliocostalis lumborum) and 12-17% (multifidus). Maximum±STD of the global and local muscles forces were 13% and 8% of the body weight. Large inter-individual differences were found in peak compressive and trunk muscles forces whereas the sensitivity analysis also showed a substantial variation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Reflex response and control of the human soleus and gastrocnemius muscles during walking and running at increasing velocity

    DEFF Research Database (Denmark)

    Simonsen, Erik B; Alkjær, Tine; Raffalt, Peter C

    2012-01-01

    than the soleus H-reflex. In both muscles the H-reflex increased significantly from walking to running but also with increasing running speed. The peak of EMG activity increased in both muscles with increasing speed. The V-wave of both muscles was absent or rather low during walking, but it increased...... significantly from walking to running with increasing running speed in the soleus but not in the medial gastrocnemius. In both muscles the V-wave was highest just prior to heel strike. It is suggested that this was due to a high firing frequency of the motoneurones in this phase of the movement. It is concluded...

  6. Inward Flux of Lactate- through Monocarboxylate Transporters Contributes to Regulatory Volume Increase in Mouse Muscle Fibres

    Science.gov (United States)

    Lindinger, Michael I.; Leung, Matthew J.; Hawke, Thomas J.

    2013-01-01

    Mouse and rat skeletal muscles are capable of a regulatory volume increase (RVI) after they shrink (volume loss resultant from exposure to solutions of increased osmolarity) and that this RVI occurs mainly by a Na-K-Cl-Cotransporter (NKCC) - dependent mechanism. With high-intensity exercise, increased extracellular osmolarity is accompanied by large increases in extracellular [lactate-]. We hypothesized that large increases in [lactate-] and osmolarity augment the NKCC-dependent RVI response observed with a NaCl (or sucrose) - induced increase in osmolarity alone; a response that is dependent on lactate- influx through monocarboxylate transporters (MCTs). Single mouse muscle fibres were isolated and visualized under light microscopy under varying osmolar conditions. When solution osmolarity was increased by adding NaLac by 30 or 60 mM, fibres lost significantly less volume and regained volume sooner compared to when NaCl was used. Phloretin (MCT1 inhibitor) accentuated the volume loss compared to both NaLac controls, supporting a role for MCT1 in the RVI response in the presence of elevated [lactate-]. Inhibition of MCT4 (with pCMBS) resulted in a volume loss, intermediate to that seen with phloretin and NaLac controls. Bumetanide (NKCC inhibitor), in combination with pCMBS, reduced the magnitude of volume loss, but volume recovery was complete. While combined phloretin-bumetanide also reduced the magnitude of the volume loss, it also largely abolished the cell volume recovery. In conclusion, RVI in skeletal muscle exposed to raised tonicity and [lactate-] is facilitated by inward flux of solute by NKCC- and MCT1-dependent mechanisms. This work demonstrates evidence of a RVI response in skeletal muscle that is facilitated by inward flux of solute by MCT-dependent mechanisms. These findings further expand our understanding of the capacities for skeletal muscle to volume regulate, particularly in instances of raised tonicity and lactate- concentrations, as occurs

  7. Inward flux of lactate⁻ through monocarboxylate transporters contributes to regulatory volume increase in mouse muscle fibres.

    Directory of Open Access Journals (Sweden)

    Michael I Lindinger

    Full Text Available Mouse and rat skeletal muscles are capable of a regulatory volume increase (RVI after they shrink (volume loss resultant from exposure to solutions of increased osmolarity and that this RVI occurs mainly by a Na-K-Cl-Cotransporter (NKCC-dependent mechanism. With high-intensity exercise, increased extracellular osmolarity is accompanied by large increases in extracellular [lactate⁻]. We hypothesized that large increases in [lactate⁻] and osmolarity augment the NKCC-dependent RVI response observed with a NaCl (or sucrose-induced increase in osmolarity alone; a response that is dependent on lactate⁻ influx through monocarboxylate transporters (MCTs. Single mouse muscle fibres were isolated and visualized under light microscopy under varying osmolar conditions. When solution osmolarity was increased by adding NaLac by 30 or 60 mM, fibres lost significantly less volume and regained volume sooner compared to when NaCl was used. Phloretin (MCT1 inhibitor accentuated the volume loss compared to both NaLac controls, supporting a role for MCT1 in the RVI response in the presence of elevated [lactate⁻]. Inhibition of MCT4 (with pCMBS resulted in a volume loss, intermediate to that seen with phloretin and NaLac controls. Bumetanide (NKCC inhibitor, in combination with pCMBS, reduced the magnitude of volume loss, but volume recovery was complete. While combined phloretin-bumetanide also reduced the magnitude of the volume loss, it also largely abolished the cell volume recovery. In conclusion, RVI in skeletal muscle exposed to raised tonicity and [lactate⁻] is facilitated by inward flux of solute by NKCC- and MCT1-dependent mechanisms. This work demonstrates evidence of a RVI response in skeletal muscle that is facilitated by inward flux of solute by MCT-dependent mechanisms. These findings further expand our understanding of the capacities for skeletal muscle to volume regulate, particularly in instances of raised tonicity and lactate

  8. Interleukin-6 markedly decreases skeletal muscle protein turnover and increases nonmuscle amino acid utilization in healthy individuals

    DEFF Research Database (Denmark)

    van Hall, Gerrit; Steensberg, Adam; Fischer, Christian

    2008-01-01

    CONTEXT: IL-6 is a key modulator of immune function and suggested to be involved in skeletal muscle wasting as seen in sepsis. OBJECTIVE: Our objective was to determine the role of IL-6 in human in vivo systemic and skeletal muscle amino acid metabolism and protein turnover. SUBJECTS AND METHODS:...

  9. Delayed trunk muscle reflex responses increase the risk of low back injuries.

    Science.gov (United States)

    Cholewicki, Jacek; Silfies, Sheri P; Shah, Riaz A; Greene, Hunter S; Reeves, N Peter; Alvi, Kashif; Goldberg, Barry

    2005-12-01

    Prospective observational study with a 2- to 3-year follow-up. To determine whether delayed muscle reflex response to sudden trunk loading is a result of or a risk factor for sustaining a low back injury (LBI). Differences in motor control have been identified in individuals with chronic low back pain and in athletes with a history of LBI when compared with controls. However, it is not known whether these changes are a risk for or a result of LBI. Muscle reflex latencies in response to a quick force release in trunk flexion, extension, and lateral bending were measured in 303 college athletes. Information was also obtained regarding their personal data, athletic experience, and history of LBI. The data were entered into a binary logistic regression model to identify the predictors of future LBI. RESULTS.: A total of 292 athletes were used for the final analysis (148 females and 144 males). During the follow-up period, 31 (11%) athletes sustained an LBI. The regression model, consisting of history of LBI, body weight, and the latency of muscles shutting off during flexion and lateral bending load releases, predicted correctly 74% of LBI outcomes. The odds of sustaining LBI increased 2.8-fold when a history of LBI was present and increased by 3% with each millisecond of abdominal muscle shut-off latency. On average, this latency was 14 milliseconds longer for athletes who sustained LBI in comparison to athletes who did not sustain LBI (77 [36] vs. 63 [31]). There were no significant changes in any of the muscle response latencies on retest following the injury. The delayed muscle reflex response significantly increases the odds of sustaining an LBI. These delayed latencies appear to be a preexisting risk factor and not the effect of an LBI.

  10. Muscle strength and carotid artery flow velocity is associated with increased risk of atherosclerosis in adults.

    Science.gov (United States)

    Park, Jinkee; Park, Hyuntae

    2017-01-01

    Carotid intima-media thickness (CIMT) has been proposed as a surrogate marker of atherosclerotic disease. In addition, carotid flow velocity (FV) and muscle strength (MS) are reported to be associated with increased CIMT. As there remains insufficient evidence for a complex association of CIMT with FV and MS, the aim of this study was to examine this association in adults. A total of 426 adults participated in this study. MS in all subjects was measured by hand grip strength. Carotid variables were measured with B-mode ultrasound. Analysis of covariance (ANCOVA) was performed to assess independent differences in the CIMT among four groups, according to the level of peak systolic flow velocity (PSV) and MS after multivariate adjustment. Logistic regression analysis was performed to calculate odds ratios (OR) and 95% confidence intervals (CI) for the independent as-sociations between PSV and MS and the estimated risk of atherosclerosis. Increased CIMT is associated with MS and PSV. ANCOVA showed that the CIMT varied significantly among groups according to the level of PSV and MS after multivariate adjustment. When calculated for the estimated risk of carotid atherosclerosis, the adjusted OR for the low PSV and MS group was 3.87 (95% CI 1.78-8.44). The results suggest that CIMT and risk of carotid atherosclerosis are significantly cor-related with PSV and upper body MS, more closely for the PSV than for the MS after adjustment for po-tential confounders. PSV by itself, and/or PSV with grip strength may be an indicator of atherosclerotic plaque instability. (Cardiol J 2017; 24, 4: 385-392).

  11. Lactobacillus plantarum TWK10 Supplementation Improves Exercise Performance and Increases Muscle Mass in Mice

    Directory of Open Access Journals (Sweden)

    Yi-Ming Chen

    2016-04-01

    Full Text Available Lactobacillus plantarum (L. plantarum is a well-known probiotic among the ingested-microorganism probiotics (i.e., ingested microorganisms associated with beneficial effects for the host. However, few studies have examined the effects of L. plantarum TWK10 (LP10 supplementation on exercise performance, physical fatigue, and gut microbial profile. Male Institute of Cancer Research (ICR strain mice were divided into three groups (n = 8 per group for oral administration of LP10 for six weeks at 0, 2.05 × 108, or 1.03 × 109 colony-forming units/kg/day, designated the vehicle, LP10-1X and LP10-5X groups, respectively. LP10 significantly decreased final body weight and increased relative muscle weight (%. LP10 supplementation dose-dependently increased grip strength (p < 0.0001 and endurance swimming time (p < 0.001 and decreased levels of serum lactate (p < 0.0001, ammonia (p < 0.0001, creatine kinase (p = 0.0118, and glucose (p = 0.0151 after acute exercise challenge. The number of type I fibers (slow muscle in gastrocnemius muscle significantly increased with LP10 treatment. In addition, serum levels of albumin, blood urea nitrogen, creatinine, and triacylglycerol significantly decreased with LP10 treatment. Long-term supplementation with LP10 may increase muscle mass, enhance energy harvesting, and have health-promotion, performance-improvement, and anti-fatigue effects.

  12. Lactobacillus plantarum TWK10 Supplementation Improves Exercise Performance and Increases Muscle Mass in Mice.

    Science.gov (United States)

    Chen, Yi-Ming; Wei, Li; Chiu, Yen-Shuo; Hsu, Yi-Ju; Tsai, Tsung-Yu; Wang, Ming-Fu; Huang, Chi-Chang

    2016-04-07

    Lactobacillus plantarum (L. plantarum) is a well-known probiotic among the ingested-microorganism probiotics (i.e., ingested microorganisms associated with beneficial effects for the host). However, few studies have examined the effects of L. plantarum TWK10 (LP10) supplementation on exercise performance, physical fatigue, and gut microbial profile. Male Institute of Cancer Research (ICR) strain mice were divided into three groups (n = 8 per group) for oral administration of LP10 for six weeks at 0, 2.05 × 10⁸, or 1.03 × 10⁹ colony-forming units/kg/day, designated the vehicle, LP10-1X and LP10-5X groups, respectively. LP10 significantly decreased final body weight and increased relative muscle weight (%). LP10 supplementation dose-dependently increased grip strength (p < 0.0001) and endurance swimming time (p < 0.001) and decreased levels of serum lactate (p < 0.0001), ammonia (p < 0.0001), creatine kinase (p = 0.0118), and glucose (p = 0.0151) after acute exercise challenge. The number of type I fibers (slow muscle) in gastrocnemius muscle significantly increased with LP10 treatment. In addition, serum levels of albumin, blood urea nitrogen, creatinine, and triacylglycerol significantly decreased with LP10 treatment. Long-term supplementation with LP10 may increase muscle mass, enhance energy harvesting, and have health-promotion, performance-improvement, and anti-fatigue effects.

  13. A Longitudinal Study of Body Image and Strategies to Lose Weight and Increase Muscles among Children

    Science.gov (United States)

    McCabe, M. P.; Ricciardelli, L. A.

    2005-01-01

    A longitudinal study was used to examine age differences in the role of body mass index (BMI) and sociocultural pressures in predicting changes in body image and strategies to both lose weight and increase muscles among 443 children aged between 8 and 12 years (207 boys, 236 girls) over a 16-month period. The strongest predictors of body image and…

  14. Exercise-induced regulation of matrix metalloproteinases in the skeletal muscle of subjects with type 2 diabetes

    DEFF Research Database (Denmark)

    Scheede-Bergdahl, Celena; Bergdahl, Andreas; Schjerling, Peter

    2014-01-01

    is maintained in the skeletal muscle of patients with uncomplicated type 2 diabetes (T2DM). Subjects [12 T2DM, 9 healthy control subjects (CON)] underwent 8 weeks of physical training. Messenger RNA (mRNA) was measured at baseline, during and after 8 weeks of training. Protein was measured pre- and post......-training. At baseline, there were no effects of diabetes on MMP or TIMP mRNA or protein. mRNA and protein response to training was similar in both groups, except active MMP-2 protein was elevated post training in T2DM only. Our results indicate that exercise-induced stimulation of MMPs is preserved in skeletal muscle......Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMP) play a critical role during vascular remodelling, in both health and disease. Impaired MMP regulation is associated with many diabetes-related complications. This study examined whether exercise-induced regulation of MMPs...

  15. Immediate Effects of Neurodynamic Sliding versus Muscle Stretching on Hamstring Flexibility in Subjects with Short Hamstring Syndrome

    OpenAIRE

    Yolanda Castellote-Caballero; Valenza, Maríe C.; Puentedura, Emilio J.; César Fernández-de-las-Peñas; Francisco Alburquerque-Sendín

    2014-01-01

    Background. Hamstring injuries continue to affect active individuals and although inadequate muscle extensibility remains a commonly accepted factor, little is known about the most effective method to improve flexibility. Purpose. To determine if an isolated neurodynamic sciatic sliding technique would improve hamstring flexibility to a greater degree than stretching or a placebo intervention in asymptomatic subjects with short hamstring syndrome (SHS). Study Design. Randomized double-blind...

  16. GH receptor signaling in skeletal muscle and adipose tissue in human subjects following exposure to an intravenous GH bolus

    DEFF Research Database (Denmark)

    Jørgensen, Jens O L; Jessen, Niels; Pedersen, Steen Bønløkke

    2006-01-01

    was measured by in vitro phosphorylation of PI. STAT5 DNA binding activity was assessed with EMSA, and the expression of IGF-I and SOCS mRNA was measured by real-time RT-PCR. GH induced a 52% increase in circulating FFA levels with peak values after 155 min (P = 0.03). Tyrosine-phosphorylated STAT5...... = 3) min after an intravenous bolus of GH (0.5 mg) vs. saline in conjunction with serum sampling in six healthy males after an overnight fast. Expression of the following signal proteins were assayed by Western blotting: STAT5/p-STAT5, MAPK, and Akt/PKB. IRS-1-associated PI 3-kinase activity...... was detected in muscle and fat of all subjects after GH. Activation of MAPK was observed in several lysates but without GH dependency. Neither PKB/Akt nor PI 3-kinase activity was affected by GH. GH-induced STAT5 DNA binding and expression of IGF-I mRNA were detected in fat, whereas expression of SOCS-1 and -3...

  17. Leukocytosis, muscle damage and increased lymphocyte proliferative response after an adventure sprint race

    Directory of Open Access Journals (Sweden)

    R. Tossige-Gomes

    2014-06-01

    Full Text Available The effect of an adventure sprint race (ASR on T-cell proliferation, leukocyte count and muscle damage was evaluated. Seven young male runners completed an ASR in the region of Serra do Espinhaço, Brazil. The race induced a strong leukocytosis (6.22±2.04×103 cells/mm3 before vs 14.81±3.53×103 cells/mm3 after the race, marked by a significant increase of neutrophils and monocytes (P<0.05, but not total lymphocytes, CD3+CD4+ or CD3+CD8+ cells. However, the T-cell proliferative response to mitogenic stimulation was increased (P=0.025 after the race, which contradicted our hypothesis that ASR, as a high-demand competition, would inhibit T-cell proliferation. A positive correlation (P=0.03, r=0.79 was observed between the proliferative response of lymphocytes after the race and the time to complete the race, suggesting that the proliferative response was dependent on exercise intensity. Muscle damage was evident after the race by increased serum levels of aspartate amino transferase (24.99±8.30 vs 50.61±15.76 U/L, P=0.003. The results suggest that humoral factors and substances released by damaged muscle may be responsible for lymphocyte activation, which may be involved in muscle recovery and repair.

  18. Nandrolone reduces activation of Notch signaling in denervated muscle associated with increased Numb expression

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xin-Hua [Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peter VA Medical Center, Bronx, NY 10468 (United States); Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029 (United States); Yao, Shen; Qiao, Rui-Fang; Levine, Alice C. [Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029 (United States); Kirschenbaum, Alexander [Department of Urology, Mount Sinai School of Medicine, New York, NY 10029 (United States); Pan, Jiangping; Wu, Yong [Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peter VA Medical Center, Bronx, NY 10468 (United States); Qin, Weiping [Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peter VA Medical Center, Bronx, NY 10468 (United States); Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029 (United States); Bauman, William A. [Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peter VA Medical Center, Bronx, NY 10468 (United States); Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029 (United States); Rehabilitation Medicine, Mount Sinai School of Medicine, New York, NY 10029 (United States); Cardozo, Christopher P., E-mail: chris.cardozo@mssm.edu [Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peter VA Medical Center, Bronx, NY 10468 (United States); Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029 (United States); Rehabilitation Medicine, Mount Sinai School of Medicine, New York, NY 10029 (United States)

    2011-10-14

    Highlights: {yields} Nerve transection increased Notch signaling in paralyzed muscle. {yields} Nandrolone prevented denervation-induced Notch signaling. {yields} Nandrolone induced the expression of an inhibitor of the Notch signaling, Numb. {yields} Reduction of denervation-induced Notch signaling by nandrolone is likely through upregulation of Numb. -- Abstract: Nandrolone, an anabolic steroid, slows denervation-atrophy in rat muscle. The molecular mechanisms responsible for this effect are not well understood. Androgens and anabolic steroids activate Notch signaling in animal models of aging and thereby mitigate sarcopenia. To explore the molecular mechanisms by which nandrolone prevents denervation-atrophy, we investigated the effects of nandrolone on Notch signaling in denervated rat gastrocnemius muscle. Denervation significantly increased Notch activity reflected by elevated levels of nuclear Notch intracellular domain (NICD) and expression of Hey1 (a Notch target gene). Activation was greatest at 7 and 35 days after denervation but remained present at 56 days after denervation. Activation of Notch in denervated muscle was prevented by nandrolone associated with upregulated expression of Numb mRNA and protein. These data demonstrate that denervation activates Notch signaling, and that nandrolone abrogates this response associated with increased expression of Numb, suggesting a potential mechanism by which nandrolone reduces denervation-atrophy.

  19. Magnesium enhances exercise performance via increasing glucose availability in the blood, muscle, and brain during exercise.

    Directory of Open Access Journals (Sweden)

    Hsuan-Ying Chen

    Full Text Available Glucose mobilization and utilization in the periphery and central nervous system are important during exercise and are responsible for exercise efficacy. Magnesium (Mg is involved in energy production and plays a role in exercise performance. This study aimed to explore the effects of Mg on the dynamic changes in glucose and lactate levels in the muscle, blood and brain of exercising rats using a combination of auto-blood sampling and microdialysis. Sprague-Dawley rats were pretreated with saline or magnesium sulfate (MgSO4, 90 mg/kg, i.p. 30 min before treadmill exercise (20 m/min for 60 min. Our results indicated that the muscle, blood, and brain glucose levels immediately increased during exercise, and then gradually decreased to near basal levels in the recovery periods of both groups. These glucose levels were significantly enhanced to approximately two-fold (P<0.05 in the Mg group. Lactate levels in the muscle, blood, and brain rapidly and significantly increased in both groups during exercise, and brain lactate levels in the Mg group further elevated (P<0.05 than those in the control group during exercise. Lactate levels significantly decreased after exercise in both groups. In conclusion, Mg enhanced glucose availability in the peripheral and central systems, and increased lactate clearance in the muscle during exercise.

  20. Meat quality traits and muscle characteristics in high or low fear lines of Japanese quails (Coturnix japonica) subjected to acute stress.

    Science.gov (United States)

    Remignon, H; Mills, A D; Guemene, D; Desrosiers, V; Garreau-Mills, M; Marche, M; Marche, G

    1998-07-01

    1. The influence of acute stress before slaughter on muscle and meat quality was studied in adult male quail from lines divergently selected for long (LTI) or short (STI) duration of tonic immobility (TI) and from the unselected (C) control line. 2. When subjected to acute stress, birds from the long TI line responded differently to those of the control or the low fear lines. LTI birds exhibited: a higher plasma creatine kinase and a smaller increase in plasma corticosterone levels, a higher pHu and drip loss values for breast meat associated with no differences in L*a*b* colour values; a higher percentage of fast glycolytic myofibres (IIb) and correspondingly (correlate) higher glycolytic (activity) in the pectoralis major (PM) muscle, and consequently lower oxidative enzyme activity in the PM muscle. 3. It is concluded that acute stress affected muscle metabolism differently in the STI, C and LTI lines. Hence, selection for TI, which is correlated with underlying fearfulness, can indirectly lead to differences in meat quality.

  1. Insulin Resistance in Non-Obese Subjects Is Associated with Activation of the JNK Pathway and Impaired Insulin Signaling in Skeletal Muscle

    Science.gov (United States)

    Masharani, Umesh B.; Maddux, Betty A.; Li, Xiaojuan; Sakkas, Giorgos K.; Mulligan, Kathleen; Schambelan, Morris; Goldfine, Ira D.; Youngren, Jack F.

    2011-01-01

    Background The pathogenesis of insulin resistance in the absence of obesity is unknown. In obesity, multiple stress kinases have been identified that impair the insulin signaling pathway via serine phosphorylation of key second messenger proteins. These stress kinases are activated through various mechanisms related to lipid oversupply locally in insulin target tissues and in various adipose depots. Methodology/Principal Findings To explore whether specific stress kinases that have been implicated in the insulin resistance of obesity are potentially contributing to insulin resistance in non-obese individuals, twenty healthy, non-obese, normoglycemic subjects identified as insulin sensitive or resistant were studied. Vastus lateralis muscle biopsies obtained during euglycemic, hyperinsulinemic clamp were evaluated for insulin signaling and for activation of stress kinase pathways. Total and regional adipose stores and intramyocellular lipids (IMCL) were assessed by DXA, MRI and 1H-MRS. In muscle of resistant subjects, phosphorylation of JNK was increased (1.36±0.23 vs. 0.78±0.10 OD units, Pincreased (1.30±0.09 vs. 0.22±0.03 OD units, Pinsulin-stimulated tyrosine phosphorylation decreased (10.97±0.95 vs. 0.89±0.50 OD units, Pinsulin resistant subjects (3.26±0.48 vs. 1.58±0.35% H2O peak, Pincreased total fat and abdominal fat when compared to insulin sensitive controls. Conclusions This is the first report demonstrating that insulin resistance in non-obese, normoglycemic subjects is associated with activation of the JNK pathway related to increased IMCL and higher total body and abdominal adipose stores. While JNK activation is consistent with a primary impact of muscle lipid accumulation on metabolic stress, further work is necessary to determine the relative contributions of the various mediators of impaired insulin signaling in this population. PMID:21589939

  2. p53 increases caspase-6 expression and activation in muscle tissue expressing mutant huntingtin.

    Science.gov (United States)

    Ehrnhoefer, Dagmar E; Skotte, Niels H; Ladha, Safia; Nguyen, Yen T N; Qiu, Xiaofan; Deng, Yu; Huynh, Khuong T; Engemann, Sabine; Nielsen, Signe M; Becanovic, Kristina; Leavitt, Blair R; Hasholt, Lis; Hayden, Michael R

    2014-02-01

    Activation of caspase-6 in the striatum of both presymptomatic and affected persons with Huntington's disease (HD) is an early event in the disease pathogenesis. However, little is known about the role of caspase-6 outside the central nervous system (CNS) and whether caspase activation might play a role in the peripheral phenotypes, such as muscle wasting observed in HD. We assessed skeletal muscle tissue from HD patients and well-characterized mouse models of HD. Cleavage of the caspase-6 specific substrate lamin A is significantly increased in skeletal muscle obtained from HD patients as well as in muscle tissues from two different HD mouse models. p53, a transcriptional activator of caspase-6, is upregulated in neuronal cells and tissues expressing mutant huntingtin. Activation of p53 leads to a dramatic increase in levels of caspase-6 mRNA, caspase-6 activity and cleavage of lamin A. Using mouse embryonic fibroblasts (MEFs) from YAC128 mice, we show that this increase in caspase-6 activity can be mitigated by pifithrin-α (pifα), an inhibitor of p53 transcriptional activity, but not through the inhibition of p53's mitochondrial pro-apoptotic function. Remarkably, the p53-mediated increase in caspase-6 expression and activation is exacerbated in cells and tissues of both neuronal and peripheral origin expressing mutant huntingtin (Htt). These findings suggest that the presence of the mutant Htt protein enhances p53 activity and lowers the apoptotic threshold, which activates caspase-6. Furthermore, these results suggest that this pathway is activated both within and outside the CNS in HD and may contribute to both loss of CNS neurons and muscle atrophy.

  3. Assessment of paraspinal muscle hardness in subjects with a mild single scoliosis curve: a preliminary myotonometer study.

    Science.gov (United States)

    Oliva-Pascual-Vaca, Ángel; Heredia-Rizo, Alberto Marcos; Barbosa-Romero, Alejandro; Oliva-Pascual-Vaca, Jesús; Rodríguez-Blanco, Cleofás; Tejero-García, Sergio

    2014-06-01

    The purpose of this study was to evaluate the hardness of the paraspinal muscles in the convexity and concavity of patients with scoliosis curvatures and in the upper trapezius (UT) muscle in subjects with mild idiopathic scoliosis (IS) and to observe the correlation between the myotonometer (MYO) measurements and the value of body mass index (BMI) and the Cobb angle. The sample included 13 patients with a single-curve mild IS (Risser sign ≤ 4) at thoracic, lumbar, or thoracolumbar level (mean Cobb angle of 11.53º). Seven females and 6 males were recruited, with a mean age of 12.84 ± 3.06 (9-18) years. A MYO was used to examine the differences in muscle hardness on both sides of the scoliosis curvature at several points: (a) apex of the curve, (b) upper and lower limits of the curve, and (c) the midpoint between the apex and the upper limit and between the apex and the lower limit. The UT was also explored. Although the MYO recorded lower values in all points on the concave side of the scoliosis, there were no significant differences in the comparison between sides (P > .05). No association was observed between BMI and MYO values, whereas the Cobb angle negatively correlated with muscle hardness only at 2 points on the convex side. The preliminary findings show that, in subjects with a single-curve mild IS, muscular hardness in the UT and paraspinal muscles, as assessed using a MYO, was not found to differ between the concave and the convex sides at different reference levels. Copyright © 2014 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

  4. Abnormally Small Neuromuscular Junctions in the Extraocular Muscles From Subjects With Idiopathic Nystagmus and Nystagmus Associated With Albinism.

    Science.gov (United States)

    McLoon, Linda K; Willoughby, Christy L; Anderson, Jill S; Bothun, Erick D; Stager, David; Felius, Joost; Lee, Helena; Gottlob, Irene

    2016-04-01

    Infantile nystagmus syndrome (INS) is often associated with abnormalities of axonal outgrowth and connectivity. To determine if this manifests in extraocular muscle innervation, specimens from children with idiopathic INS or INS and albinism were examined and compared to normal age-matched control extraocular muscles. Extraocular muscles removed during normal surgery on children with idiopathic INS or INS and albinism were immunostained for neuromuscular junctions, myofiber type, the immature form of the acetylcholine receptor, and brain-derived neurotrophic factor (BDNF) and compared to age-matched controls. Muscles from both the idiopathic INS and INS and albinism groups had neuromuscular junctions that were 35% to 71% smaller based on myofiber area and myofiber perimeter than found in age-matched controls, and this was seen on both fast and slow myosin heavy chain isoform-expressing myofibers (all P albinism showed a 7-fold increase in neuromuscular junction numbers on fast myofibers expressing the immature gamma subunit of the acetylcholine receptor. The extraocular muscles from both INS subgroups showed a significant increase in the number and size of slow myofibers compared to age-matched controls. Brain-derived neurotrophic factor was expressed in control muscle but was virtually absent in the INS muscles. These studies suggest that, relative to the final common pathway, INS is not the same between different patient etiologies. It should be possible to modulate these final common pathway abnormalities, via exogenous application of appropriate drugs, with the hope that this type of treatment may reduce the involuntary oscillatory movements in these children.

  5. Elevation of serum insulin concentration during euglycemic hyperinsulinemic clamp studies leads to similar activation of insulin receptor kinase in skeletal muscle of subjects with and without NIDDM

    DEFF Research Database (Denmark)

    Klein, H H; Vestergaard, H; Kotzke, G

    1995-01-01

    The role of skeletal muscle insulin receptor kinase in the pathogenesis of non-insulin-dependent diabetes mellitus (NIDDM) was investigated. Muscle biopsies from 13 patients with NIDDM and 10 control subjects at fasting serum insulin concentrations and approximately 1,000 pmol/l steady-state serum...... insulin during euglycemic hyperinsulinemic clamps were immediately frozen. The biopsies were then solubilized, and the receptors were immobilized to anti-insulin receptor antibody-coated microwells. Receptor kinase and binding activities were consecutively measured in these wells. The increase in serum...... insulin concentration (73 +/- 14 to 1,004 +/- 83 and 45 +/- 7 to 1,07 +/- 77 pmol/l in the NIDDM and control groups, respectively) had similar effects on receptor kinase activity in both study groups (12 +/- 1 to 42 +/- 5 and 12 +/- 2 to 47 +/- 5 amol P.fmol binding activity-1. min-1 in the NIDDM...

  6. Effect of toe-spread-out exercise on hallux valgus angle and cross-sectional area of abductor hallucis muscle in subjects with hallux valgus.

    Science.gov (United States)

    Kim, Moon-Hwan; Yi, Chung-Hwi; Weon, Jong-Hyuck; Cynn, Heon-Seock; Jung, Do-Young; Kwon, Oh-Yun

    2015-04-01

    [Purpose] This study investigated whether the toe-spread-out exercise affects the hallux valgus angle, the cross-sectional area of the abductor hallucis muscle, and the hallux valgus angle during active abduction. [Subjects and Methods] Twenty-four subjects with hallux valgus were randomly assigned to orthosis and orthosis plus toe-spread-out exercise groups. The orthosis group wore the orthosis for 8 weeks, while the orthosis plus toe-spread-out group also performed the toe-spread-out exercise. The hallux valgus angle, the cross-sectional area of the abductor hallucis muscle, and the hallux valgus angle during active abduction were measured initially and after 8 weeks by radiography and ultrasonography. [Results] While there were no significant changes in the three parameters in the orthosis group, there were significant differences in the orthosis plus toe-spread-out exercise group after 8 weeks. In addition there were significant differences in the three measures between the two groups. [Conclusion] The toe-spread-out exercise reduces the hallux valgus angle and hallux valgus angle during active abduction, and increases the cross-sectional area of the abductor hallucis muscle. The toe-spread-out exercise is recommended for patients with mild to moderate hallux valgus.

  7. Actovegin, a non-prohibited drug increases oxidative capacity in human skeletal muscle

    DEFF Research Database (Denmark)

    Søndergård, Stine D; Dela, Flemming; Helge, Jørn W

    2016-01-01

    Actovegin, a deproteinized haemodialysate of calf blood, is suggested to have ergogenic properties, but this potential effect has never been investigated in human skeletal muscle. To investigate this purported ergogenic effect, we measured the mitochondrial respiratory capacity in permeabilized...... human skeletal muscle fibres acutely exposed to Actovegin in a low and in a high dose. We found that Actovegin, in the presence of complex I-linked substrates increased the oxidative phosphorylation (OXPHOS) capacity significantly in a concentration-dependent manner (19 ± 3, 31 ± 4 and 45 ± 4 pmol....../mg/s). Maximal OXPHOS capacity with complex I and II-linked substrate was increased when the fibres were exposed to the high dose of Actovegin (62 ± 6 and 77 ± 6 pmol/mg/s) (p system as well as Vmax and Km were also increased in a concentration...

  8. Control of support limb muscles in recovery after tripping in young and older subjects

    NARCIS (Netherlands)

    Pijnappels, M.A.G.M.; Bobbert, M.F.; van Dieen, J.H.

    2005-01-01

    Older people fall more often after tripping than young people due to a slower development of mechanical responses. This might be due to age-related changes in muscle properties, but also to changes in motor control. The purpose of the present study was to determine whether (a) timing and sequencing

  9. Electromyographic activity of the shoulder muscles during rehabilitation exercises in subjects with and without subacromial pain syndrome: a systematic review.

    Science.gov (United States)

    Kinsella, Rita; Pizzari, Tania

    2017-04-01

    Subacromial pain syndrome (SPS) is a common cause of shoulder pain and muscle activity deficits are postulated to contribute to the development and progression of the disorder. The purpose of this systematic review was to definitively determine whether evidence exists of differences in electromyography (EMG) characteristics between subjects with and without SPS. Six key databases were searched: MEDLINE, EMBASE, CINAHL, SPORTdiscus, PEDro and The Cochrane Library (inception to May 2016). The search yielded 1414 records using terms relating to shoulder impingement, EMG, scapular and rotator cuff muscles. Twenty-two papers remained once duplicates were removed and selection criteria applied. Data extraction, quality assessment and data synthesis were performed. Effect sizes and 95% confidence intervals were calculated. There was limited evidence that serratus anterior has lower amplitude, delayed activation and earlier termination in SPS participants. For the majority of muscles, regardless of task, load or arm position, significant differences were not demonstrated or results were contradictory. The understanding of SPS is changing and EMG appears unable to capture the complexities associated with this condition. Addressing aberrant movement patterns and facilitating balanced activation of all shoulder muscles may be a more appropriate treatment direction for the future.

  10. Power Training-induced Increases in Muscle Activation during Gait in Old Adults.

    Science.gov (United States)

    Beijersbergen, Chantal M I; Granacher, Urs; Gäbler, Martijn; Devita, Paul; Hortobágyi, Tibor

    2017-11-01

    Aging modifies neuromuscular activation of agonist and antagonist muscles during walking. Power training can evoke adaptations in neuromuscular activation that underlie gains in muscle strength and power but it is unknown if these adaptations transfer to dynamic tasks such as walking. We examined the effects of lower-extremity power training on neuromuscular activation during level gait in old adults. Twelve community-dwelling old adults (age ≥ 65 yr) completed a 10-wk lower-extremity power training program and 13 old adults completed a 10-wk control period. Before and after the interventions, we measured maximal isometric muscle strength and electromyographic (EMG) activation of the right knee flexor, knee extensor, and plantarflexor muscles on a dynamometer and we measured EMG amplitudes, activation onsets and offsets, and activation duration of the knee flexors, knee extensors, and plantarflexors during gait at habitual, fast, and standardized (1.25 ± 0.6 m·s) speeds. Power training-induced increases in EMG amplitude (~41%; 0.47 ≤ d ≤ 1.47; P ≤ 0.05) explained 33% (P = 0.049) of increases in isometric muscle strength (~43%; 0.34 ≤ d ≤ 0.80; P ≤ 0.05). Power training-induced gains in plantarflexor activation during push-off (+11%; d = 0.38; P = 0.045) explained 57% (P = 0.004) of the gains in fast gait velocity (+4%; d = 0.31; P = 0.059). Furthermore, power training increased knee extensor activation (~18%; 0.26 ≤ d ≤ 0.29; P ≤ 0.05) and knee extensor coactivation during the main knee flexor burst (~24%, 0.26 ≤ d ≤ 0.44; P ≤ 0.05) at habitual and fast speed but these adaptations did not correlate with changes in gait velocity. Power training increased neuromuscular activation during isometric contractions and level gait in old adults. The power training-induced neuromuscular adaptations were associated with increases in isometric muscle strength and partly with increases in fast gait velocity.

  11. Atherosclerotic risk factors are increased in clinically healthy subjects with microalbuminuria

    DEFF Research Database (Denmark)

    Jensen, J S; Borch-Johnsen, K; Jensen, G

    1995-01-01

    in clinically healthy subjects. All healthy 40-65 year-old participants with microalbuminuria, examined within the first 21 months of The Copenhagen City Heart Study, were invited, and 28 were studied. An age- and sex-matched group of 60 randomly chosen subjects with normoalbuminuria served as control......Increased morbidity and mortality from atherosclerotic vascular disease were observed in subjects with slightly elevated urinary albumin excretion rate (UAER), known as microalbuminuria. Therefore, the association between microalbuminuria and established atherogenic risk factors was studied...... and fasting serum insulin concentration were slightly elevated in the microalbuminuric group but not statistically significant. It is concluded that microalbuminuria in clinically healthy subjects is associated with increased levels of atherogenic risk factors. This may contribute to the increased vascular...

  12. Masticatory muscle activity evaluation by electromyography in subjects with zygomatic implants

    Science.gov (United States)

    de Rossi, Moara; Lucas, Bárbara; Santos, Carla; Semprini, Marisa; Oliveira, Ligia; Regalo, Isabela; Bersani, Edmilson; Migliorança, Reginaldo; Siéssere, Selma; Regalo, Simone

    2017-01-01

    Background Zygomatic implants are an alternative treatment in the rehabilitation of atrophic maxilla to promote stability in the stomatognathic system. The aim of this study was to compare the electromyographic (EMG) activity of masseter and temporalis muscles in controls and in individuals with complete implant-supported dentures anchored in the zygomatic bone. Material and Methods Fifty-four volunteers of both genders (mean age 52.5 years) were selected and distributed into two groups: Individuals with zygomatic implant (ZIG; n=27) and fully dentate patients (CG; n=27). MyoSystem-BR1 was used to assess masseter and temporalis muscles EMG activity in different mandibular movements: protrusion, clenching, maximal voluntary contraction (MVC) with Parafilm M®, right and left laterality and chewing (peanuts and raisins). Data was processed, normalized (MVC) and analyzed using the SPSS 21.0. Student t-test (P ≤ 0.05) was used for group comparison. Results The results were statistically significant (P ≤ 0.05) for protrusion, clenching, right and left laterality and raisin chewing. For the mandibular posture conditions, the ZIG obtained higher EMG activity patterns when compared to CG. For the masticatory performance during chewing of peanuts and raisins, the ZIG showed higher EMG mean values when compared to CG. Conclusions The zygomatic implant promoted an active response of the muscle fibers (hyperactivity) during both mandibular posture and chewing conditions, probably due to the absence of periodontal receptors, which play a significant role for preparing a bolus for swallowing. Key words:Zygomatic implant, electromyography, masseter muscle, temporal muscle. PMID:28390128

  13. Creatine supplementation augments the increase in satellite cell and myonuclei number in human skeletal muscle induced by strength training

    DEFF Research Database (Denmark)

    Olsen, Steen; Aagaard, Per; Kadi, Fawzi

    2006-01-01

    The present study investigated the influence of creatine and protein supplementation on satellite cell frequency and number of myonuclei in human skeletal muscle during 16 weeks of heavy-resistance training. In a double-blinded design 32 healthy, male subjects (19-26 years) were assigned to stren......The present study investigated the influence of creatine and protein supplementation on satellite cell frequency and number of myonuclei in human skeletal muscle during 16 weeks of heavy-resistance training. In a double-blinded design 32 healthy, male subjects (19-26 years) were assigned...... to strength training (STR) while receiving a timed intake of creatine (STR-CRE) (n=9), protein (STR-PRO) (n=8) or placebo (STR-CON) (n=8), or serving as a non-training control group (CON) (n=7). Supplementation was given daily (STR-CRE: 6-24 g creatine monohydrate, STR-PRO: 20 g protein, STR-CON: placebo...... histochemical analysis. All training regimes were found to increase the proportion of satellite cells, but significantly greater enhancements were observed with creatine supplementation at week 4 (compared to STR-CON) and at week 8 (compared to STR-PRO and STR-CON) (P

  14. Comparative Analysis of Muscle Hypertrophy Models Reveals Divergent Gene Transcription Profiles and Points to Translational Regulation of Muscle Growth through Increased mTOR Signaling

    Directory of Open Access Journals (Sweden)

    Marcelo G. Pereira

    2017-12-01

    Full Text Available Skeletal muscle mass is a result of the balance between protein breakdown and protein synthesis. It has been shown that multiple conditions of muscle atrophy are characterized by the common regulation of a specific set of genes, termed atrogenes. It is not known whether various models of muscle hypertrophy are similarly regulated by a common transcriptional program. Here, we characterized gene expression changes in three different conditions of muscle growth, examining each condition during acute and chronic phases. Specifically, we compared the transcriptome of Extensor Digitorum Longus (EDL muscles collected (1 during the rapid phase of postnatal growth at 2 and 4 weeks of age, (2 24 h or 3 weeks after constitutive activation of AKT, and (3 24 h or 3 weeks after overload hypertrophy caused by tenotomy of the Tibialis Anterior muscle. We observed an important overlap between significantly regulated genes when comparing each single condition at the two different timepoints. Furthermore, examining the transcriptional changes occurring 24 h after a hypertrophic stimulus, we identify an important role for genes linked to a stress response, despite the absence of muscle damage in the AKT model. However, when we compared all different growth conditions, we did not find a common transcriptional fingerprint. On the other hand, all conditions showed a marked increase in mTORC1 signaling and increased ribosome biogenesis, suggesting that muscle growth is characterized more by translational, than transcriptional regulation.

  15. Saffron (Crocus sativus L.) increases glucose uptake and insulin sensitivity in muscle cells via multipathway mechanisms.

    Science.gov (United States)

    Kang, Changkeun; Lee, Hyunkyoung; Jung, Eun-Sun; Seyedian, Ramin; Jo, MiNa; Kim, Jehein; Kim, Jong-Shu; Kim, Euikyung

    2012-12-15

    Saffron (Crocus sativus Linn.) has been an important subject of research in the past two decades because of its various biological properties, including anti-cancer, anti-inflammatory, and anti-atherosclerotic activities. On the other hand, the molecular bases of its actions have been scarcely understood. Here, we elucidated the mechanism of the hypoglycemic actions of saffron through investigating its signaling pathways associated with glucose metabolism in C(2)C(12) skeletal muscle cells. Saffron strongly enhanced glucose uptake and the phosphorylation of AMPK (AMP-activated protein kinase)/ACC (acetyl-CoA carboxylase) and MAPKs (mitogen-activated protein kinases), but not PI 3-kinase (Phosphatidylinositol 3-kinase)/Akt. Interestingly, the co-treatment of saffron and insulin further improved the insulin sensitivity via both insulin-independent (AMPK/ACC and MAPKs) and insulin-dependent (PI 3-kinase/Akt and mTOR) pathways. It also suggested that there is a crosstalk between the two signaling pathways of glucose metabolism in skeletal muscle cells. These results could be confirmed from the findings of GLUT4 translocation. Taken together, AMPK plays a major role in the effects of saffron on glucose uptake and insulin sensitivity in skeletal muscle cells. Our study provides important insights for the possible mechanism of action of saffron and its potential as a therapeutic agent in diabetic patients. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Increased skeletal muscle glucose uptake by rosemary extract through AMPK activation.

    Science.gov (United States)

    Naimi, Madina; Tsakiridis, Theodoros; Stamatatos, Theocharis C; Alexandropoulos, Dimitris I; Tsiani, Evangelia

    2015-04-01

    Stimulation of the energy sensor AMP-activated kinase (AMPK) has been viewed as a targeted approach to increase glucose uptake by skeletal muscle and control blood glucose homeostasis. Rosemary extract (RE) has been reported to activate AMPK in hepatocytes and reduce blood glucose levels in vivo but its effects on skeletal muscle are not known. In the present study, we examined the effects of RE and the mechanism of regulation of glucose uptake in muscle cells. RE stimulated glucose uptake in L6 myotubes in a dose- and time-dependent manner. Maximum stimulation was seen with 5 μg/mL of RE for 4 h (184% ± 5.07% of control, p glucose uptake was significantly reduced by the AMPK inhibitor compound C, but remained unchanged by the PI3K inhibitor, wortmannin. RE did not affect GLUT4 or GLUT1 glucose transporter translocation in contrast with a significant translocation of both transporters seen with insulin or metformin treatment. Our study is the first to show a direct effect of RE on muscle cell glucose uptake by a mechanism that involves AMPK activation.

  17. ANODAL TRANSCRANIAL DIRECT CURRENT STIMULATION (TDCS) INCREASES ISOMETRIC STRENGTH OF SHOULDER ROTATORS MUSCLES IN HANDBALL PLAYERS.

    Science.gov (United States)

    Hazime, Fuad Ahmad; da Cunha, Ronaldo Alves; Soliaman, Renato Rozenblit; Romancini, Ana Clara Bezerra; Pochini, Alberto de Castro; Ejnisman, Benno; Baptista, Abrahão Fontes

    2017-06-01

    Weakness of the rotator cuff muscles can lead to imbalances in the strength of shoulder external and internal rotators, change the biomechanics of the glenohumeral joint and predispose an athlete to injury. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that has demonstrated promising results in a variety of health conditions. However few studies addressed its potential approach in the realm of athletics. The purpose of this study was to investigate if transcranial direct current stimulation (tDCS) technique increases the isometric muscle strength of shoulder external and internal rotators in handball athletes. Randomized, double-blind, placebo-controlled, crossover study. Eight female handball players aged between 17 and 21 years (Mean=19.65; SD=2.55) with 7.1 ± 4.8 years of experience in training, participating in regional and national competitions were recruited. Maximal voluntary isometric contraction (MVIC) of shoulder external and internal rotator muscles was evaluated during and after 30 and 60 minutes post one session of anodal and sham current (2mA; 0.057mA/cm2) with a one-week interval between stimulations. Compared to baseline, MVIC of shoulder external and internal rotators significantly increased after real but not sham tDCS. Between-group differences were observed for external and internal rotator muscles. Maximal voluntary isometric contraction of external rotation increased significantly during tDCS, and 30 and 60 minutes post-tDCS for real tDCS compared to that for sham tDCS. For internal rotation MVIC increased significantly during and 60 minutes post-tDCS. The results indicate that transcranial direct current stimulation temporarily increases maximal isometric contractions of the internal and external rotators of the shoulder in handball players. 2.

  18. Skeletal muscle-specific expression of PGC-1α-b, an exercise-responsive isoform, increases exercise capacity and peak oxygen uptake.

    Directory of Open Access Journals (Sweden)

    Miki Tadaishi

    Full Text Available Maximal oxygen uptake (VO(2max predicts mortality and is associated with endurance performance. Trained subjects have a high VO(2max due to a high cardiac output and high metabolic capacity of skeletal muscles. Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α, a nuclear receptor coactivator, promotes mitochondrial biogenesis, a fiber-type switch to oxidative fibers, and angiogenesis in skeletal muscle. Because exercise training increases PGC-1α in skeletal muscle, PGC-1α-mediated changes may contribute to the improvement of exercise capacity and VO(2max. There are three isoforms of PGC-1α mRNA. PGC-1α-b protein, whose amino terminus is different from PGC-1α-a protein, is a predominant PGC-1α isoform in response to exercise. We investigated whether alterations of skeletal muscle metabolism by overexpression of PGC-1α-b in skeletal muscle, but not heart, would increase VO(2max and exercise capacity.Transgenic mice showed overexpression of PGC-1α-b protein in skeletal muscle but not in heart. Overexpression of PGC-1α-b promoted mitochondrial biogenesis 4-fold, increased the expression of fatty acid transporters, enhanced angiogenesis in skeletal muscle 1.4 to 2.7-fold, and promoted exercise capacity (expressed by maximum speed by 35% and peak oxygen uptake by 20%. Across a broad range of either the absolute exercise intensity, or the same relative exercise intensities, lipid oxidation was always higher in the transgenic mice than wild-type littermates, suggesting that lipid is the predominant fuel source for exercise in the transgenic mice. However, muscle glycogen usage during exercise was absent in the transgenic mice.Increased mitochondrial biogenesis, capillaries, and fatty acid transporters in skeletal muscles may contribute to improved exercise capacity via an increase in fatty acid utilization. Increases in PGC-1α-b protein or function might be a useful strategy for sedentary subjects to perform exercise

  19. Evaluation of jaw and neck muscle activities while chewing using EMG-EMG transfer function and EMG-EMG coherence function analyses in healthy subjects.

    Science.gov (United States)

    Ishii, Tomohiro; Narita, Noriyuki; Endo, Hiroshi

    2016-06-01

    This study aims to quantitatively clarify the physiological features in rhythmically coordinated jaw and neck muscle EMG activities while chewing gum using EMG-EMG transfer function and EMG-EMG coherence function analyses in 20 healthy subjects. The chewing side masseter muscle EMG signal was used as the reference signal, while the other jaw (non-chewing side masseter muscle, bilateral anterior temporal muscles, and bilateral anterior digastric muscles) and neck muscle (bilateral sternocleidomastoid muscles) EMG signals were used as the examined signals in EMG-EMG transfer function and EMG-EMG coherence function analyses. Chewing-related jaw and neck muscle activities were aggregated in the first peak of the power spectrum in rhythmic chewing. The gain in the peak frequency represented the power relationships between jaw and neck muscle activities during rhythmic chewing. The phase in the peak frequency represented the temporal relationships between the jaw and neck muscle activities, while the non-chewing side neck muscle presented a broad range of distributions across jaw closing and opening phases. Coherence in the peak frequency represented the synergistic features in bilateral jaw closing muscles and chewing side neck muscle activities. The coherence and phase in non-chewing side neck muscle activities exhibited a significant negative correlation. From above, the bilateral coordination between the jaw and neck muscle activities is estimated while chewing when the non-chewing side neck muscle is synchronously activated with the jaw closing muscles, while the unilateral coordination is estimated when the non-chewing side neck muscle is irregularly activated in the jaw opening phase. Thus, the occurrence of bilateral or unilateral coordinated features in the jaw and neck muscle activities may correspond to the phase characteristics in the non-chewing side neck muscle activities during rhythmical chewing. Considering these novel findings in healthy subjects, EMG

  20. Evaluation of pelvic floor muscles activity with and without abdominal maneuvers in subjects with and without low back pain.

    Science.gov (United States)

    Ehsani, Fatemeh; Arab, Amir Massoud; Assadi, Hamed; Karimi, Noureddin; Shanbehzadeh, Sanaz

    2016-04-27

    There was controversy in finding of studies related pelvic floor muscle (PFM) rehabilitation of subjects with low back pain (LBP), while this issue is very important for treatment of subjects with LBP. The purpose of this study was to evaluate PFM contraction in three conditions of alone and with abdominal hollowing (AH) or abdominal bracing (AB) maneuvers in subjects with and without chronic LBP. Subjects were divided into two groups: subjects with LBP (N = 25) and without LBP (N = 27). PFM contraction alone and during contraction with AH or AB maneuvers was measured. The amount of bladder base movement was measured as an indicator of PFM activity. There were no differences in PFM activity between subjects with and without chronic LBP, when PFM contracted alone (P = 0.60), contracted with AH (P= 0.12) and AB maneuver (P = 0.54). Our data revealed that contraction of the PFM alone produce greater displacement of the bladder base than contraction of the PFM with AH (P = 0.005) or AB maneuver (P = 0.001) in both groups. However, no significant difference was found between contraction of the PFM with AH and AB maneuver in individuals with LBP (P = 0.31). It seems that PFM contraction alone is more effective than PFM contraction with AH or AB maneuvers in lifting the pelvic floor in subjects with and without LBP.

  1. Failure of activation of spinal motoneurones after muscle fatigue in healthy subjects studied by transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Andersen, Birgit; Westlund, Barbro; Krarup, Christian

    2003-01-01

    response depression. Overall, the results suggest that the outflow from the motor cortex could become insufficient to drive all spinal MNs to discharge when the muscle is fatigued and that complex interactions between failure of activation and compensatory mechanisms to maintain motor unit activation occur......During a sustained maximal effort a progressive decline in the ability to drive motoneurones (MNs) develops. We used the recently developed triple stimulation technique (TST) to study corticospinal conduction after fatiguing exercise in healthy subjects. This method employs a collision technique...... to estimate the proportion of motor units activated by a transcranial magnetic stimulus. Following a sustained contraction of the abductor digiti minimi muscle at 50 % maximal force maintained to exhaustion there was an immediate reduction of the TST response from > 95 % to about 60 %. This effect recovered...

  2. Increase in relative skeletal muscle mass over time and its inverse association with metabolic syndrome development: a 7-year retrospective cohort study.

    Science.gov (United States)

    Kim, Gyuri; Lee, Seung-Eun; Jun, Ji Eun; Lee, You-Bin; Ahn, Jiyeon; Bae, Ji Cheol; Jin, Sang-Man; Hur, Kyu Yeon; Jee, Jae Hwan; Lee, Moon-Kyu; Kim, Jae Hyeon

    2018-02-05

    Skeletal muscle mass was negatively associated with metabolic syndrome prevalence in previous cross-sectional studies. The aim of this study was to investigate the impact of baseline skeletal muscle mass and changes in skeletal muscle mass over time on the development of metabolic syndrome in a large population-based 7-year cohort study. A total of 14,830 and 11,639 individuals who underwent health examinations at the Health Promotion Center at Samsung Medical Center, Seoul, Korea were included in the analyses of baseline skeletal muscle mass and those changes from baseline over 1 year, respectively. Skeletal muscle mass was estimated by bioelectrical impedance analysis and was presented as a skeletal muscle mass index (SMI), a body weight-adjusted appendicular skeletal muscle mass value. Using Cox regression models, hazard ratio for developing metabolic syndrome associated with SMI values at baseline or changes of SMI over a year was analyzed. During 7 years of follow-up, 20.1% of subjects developed metabolic syndrome. Compared to the lowest sex-specific SMI tertile at baseline, the highest sex-specific SMI tertile showed a significant inverse association with metabolic syndrome risk (adjusted hazard ratio [AHR] = 0.61, 95% confidence interval [CI] 0.54-0.68). Furthermore, compared with SMI changes metabolic syndrome development were 0.87 (95% CI 0.78-0.97) for 0-1% changes and 0.67 (0.56-0.79) for > 1% changes in SMI over 1 year after additionally adjusting for baseline SMI and glycometabolic parameters. An increase in relative skeletal muscle mass over time has a potential preventive effect on developing metabolic syndrome, independently of baseline skeletal muscle mass and glycometabolic parameters.

  3. Increased BDNF promoter methylation in the Wernicke area of suicide subjects.

    Science.gov (United States)

    Keller, Simona; Sarchiapone, Marco; Zarrilli, Federica; Videtic, Alja; Ferraro, Angelo; Carli, Vladimir; Sacchetti, Silvana; Lembo, Francesca; Angiolillo, Antonella; Jovanovic, Nikolina; Pisanti, Francesco; Tomaiuolo, Rossella; Monticelli, Antonella; Balazic, Joze; Roy, Alec; Marusic, Andrej; Cocozza, Sergio; Fusco, Alfredo; Bruni, Carmelo B; Castaldo, Giuseppe; Chiariotti, Lorenzo

    2010-03-01

    Brain-derived neurotrophic factor (BDNF) plays a pivotal role in the pathophysiology of suicidal behavior and BDNF levels are decreased in the brain and plasma of suicide subjects. So far, the mechanisms leading to downregulation of BDNF expression are poorly understood. To test the hypothesis that alterations of DNA methylation could be involved in the dysregulation of BDNF gene expression in the brain of suicide subjects. Three independent quantitative methylation techniques were performed on postmortem samples of brain tissue. BDNF messenger RNA levels were determined by quantitative real-time polymerase chain reaction. Academic medical center. Forty-four suicide completers and 33 nonsuicide control subjects of white ethnicity. The DNA methylation degree at BDNF promoter IV and the genome-wide DNA methylation levels in the brain's Wernicke area. Postmortem brain samples from suicide subjects showed a statistically significant increase of DNA methylation at specific CpG sites in BDNF promoter/exon IV compared with nonsuicide control subjects (P Wernicke area of the postmortem brain of suicide subjects irrespective of genome-wide methylation levels, indicating that a gene-specific increase in DNA methylation could cause or contribute to the downregulation of BDNF expression in suicide subjects. The reported data reveal a novel link between epigenetic alteration in the brain and suicidal behavior.

  4. Central projection of pain arising from delayed onset muscle soreness (DOMS in human subjects.

    Directory of Open Access Journals (Sweden)

    Katharina Zimmermann

    Full Text Available Delayed onset muscle soreness (DOMS is a subacute pain state arising 24-48 hours after a bout of unaccustomed eccentric muscle contractions. Functional magnetic resonance imaging (fMRI was used to examine the patterns of cortical activation arising during DOMS-related pain in the quadriceps muscle of healthy volunteers evoked by either voluntary contraction or physical stimulation. The painful movement or physical stimulation of the DOMS-affected thigh disclosed widespread activation in the primary somatosensory and motor (S1, M1 cortices, stretching far beyond the corresponding areas somatotopically related to contraction or physical stimulation of the thigh; activation also included a large area within the cingulate cortex encompassing posteroanterior regions and the cingulate motor area. Pain-related activations were also found in premotor (M2 areas, bilateral in the insular cortex and the thalamic nuclei. In contrast, movement of a DOMS-affected limb led also to activation in the ipsilateral anterior cerebellum, while DOMS-related pain evoked by physical stimulation devoid of limb movement did not.

  5. Magnesium enhances exercise performance via increasing glucose availability in the blood, muscle, and brain during exercise.

    Science.gov (United States)

    Chen, Hsuan-Ying; Cheng, Fu-Chou; Pan, Huan-Chuan; Hsu, Jaw-Cheng; Wang, Ming-Fu

    2014-01-01

    Glucose mobilization and utilization in the periphery and central nervous system are important during exercise and are responsible for exercise efficacy. Magnesium (Mg) is involved in energy production and plays a role in exercise performance. This study aimed to explore the effects of Mg on the dynamic changes in glucose and lactate levels in the muscle, blood and brain of exercising rats using a combination of auto-blood sampling and microdialysis. Sprague-Dawley rats were pretreated with saline or magnesium sulfate (MgSO4, 90 mg/kg, i.p.) 30 min before treadmill exercise (20 m/min for 60 min). Our results indicated that the muscle, blood, and brain glucose levels immediately increased during exercise, and then gradually decreased to near basal levels in the recovery periods of both groups. These glucose levels were significantly enhanced to approximately two-fold (Pbrain rapidly and significantly increased in both groups during exercise, and brain lactate levels in the Mg group further elevated (Pexercise. Lactate levels significantly decreased after exercise in both groups. In conclusion, Mg enhanced glucose availability in the peripheral and central systems, and increased lactate clearance in the muscle during exercise.

  6. Multimodal high-intensity interval training increases muscle function and metabolic performance in females.

    Science.gov (United States)

    Buckley, Stephanie; Knapp, Kelly; Lackie, Amy; Lewry, Colin; Horvey, Karla; Benko, Chad; Trinh, Jason; Butcher, Scotty

    2015-11-01

    High-intensity interval training (HIIT) is a time-efficient method of improving aerobic and anaerobic power and capacity. In most individuals, however, HIIT using modalities such as cycling, running, and rowing does not typically result in increased muscle strength, power, or endurance. The purpose of this study is to compare the physiological outcomes of traditional HIIT using rowing (Row-HIIT) with a novel multimodal HIIT (MM-HIIT) circuit incorporating multiple modalities, including strength exercises, within an interval. Twenty-eight recreationally active women (age 24.7 ± 5.4 years) completed 6 weeks of either Row-HIIT or MM-HIIT and were tested on multiple fitness parameters. MM-HIIT and Row-HIIT resulted in similar improvements (p HIIT group had significant (p HIIT group had no increase in any muscle performance variable (p values 0.33-0.90). Post-training, 1-repetition maximum (1RM) squat (64.2 ± 13.6 vs. 45.8 ± 16.2 kg, p = 0.02), 1RM press (33.2 ± 3.8 vs. 26.0 ± 9.6 kg, p = 0.01), and squat endurance (23.9 ± 12.3 vs. 10.2 ± 5.6 reps, p HIIT group than in the Row-HIIT group. MM-HIIT resulted in similar aerobic and anaerobic adaptations but greater muscle performance increases than Row-HIIT in recreationally active women.

  7. Fenugreek increases insulin-stimulated creatine content in L6C11 muscle myotubes.

    Science.gov (United States)

    Tomcik, Kristyen A; Smiles, William J; Camera, Donny M; Hügel, Helmut M; Hawley, John A; Watts, Rani

    2017-04-01

    Creatine uptake by muscle cells is increased in the presence of insulin. Accordingly, compounds with insulin-like actions may also augment creatine uptake. The aim of this study was to investigate whether Trigonella foenum-graecum (fenugreek), an insulin mimetic, increases total intracellular creatine levels in vitro. Total cellular creatine content was measured fluorometrically in L6C11 muscle myotubes treated for 1, 4, and 24 h with 0.5 mM creatine (CR), CR and 20 μg/mL fenugreek seed extract (CR + FEN), CR and 100 nM insulin (CR + INS), and CR + INS + FEN (n = 6 per treatment group). Alterations in the expression of the sodium- and chloride-dependent creatine transporter, SLC6A8, and key signaling proteins in the PI3-K/Akt pathway were determined. Compared to control (CON), CR + INS + FEN increased total creatine content after 4 h (P  CON and CR at 1 h (P  CON, CR, and CR + INS at 4 h (P creatine content via a mechanism which is independent of the activity of SLC6A8, suggesting that an alternative mechanism is responsible for the regulation and facilitation of insulin-mediated creatine uptake in skeletal muscle cells.

  8. Effects of lipid-lowering drugs on irisin in human subjects in vivo and in human skeletal muscle cells ex vivo.

    Directory of Open Access Journals (Sweden)

    Ioanna Gouni-Berthold

    Full Text Available The myokine irisin has been proposed to regulate energy homeostasis. Little is known about its association with metabolic parameters and especially with parameters influencing pathways of lipid metabolism. In the context of a clinical trial, an exploratory post hoc analysis has been performed in healthy subjects to determine whether simvastatin and/or ezetimibe influence serum irisin levels. The direct effects of simvastatin on irisin were also examined in primary human skeletal muscle cells (HSKMCs.A randomized, parallel 3-group study was performed in 72 men with mild hypercholesterolemia and without apparent cardiovascular disease. Each group of 24 subjects received a 14-day treatment with either simvastatin 40 mg, ezetimibe 10 mg, or their combination.Baseline irisin concentrations were not significantly correlated with age, BMI, estimated GFR, thyroid parameters, glucose, insulin, lipoproteins, non-cholesterol sterols, adipokines, inflammation markers and various molecular markers of cholesterol metabolism. Circulating irisin increased significantly in simvastatin-treated but not in ezetimibe-treated subjects. The changes were independent of changes in LDL-cholesterol and were not correlated with changes in creatine kinase levels. In HSKMCs, simvastatin significantly increased irisin secretion as well as mRNA expression of its parent peptide hormone FNDC5. Simvastatin significantly induced cellular reactive oxygen species levels along with expression of pro- and anti-oxidative genes such as Nox2, and MnSOD and catalase, respectively. Markers of cellular stress such as atrogin-1 mRNA and Bax protein expression were also induced by simvastatin. Decreased cell viability and increased irisin secretion by simvastatin was reversed by antioxidant mito-TEMPO, implying in part that irisin is secreted as a result of increased mitochondrial oxidative stress and subsequent myocyte damage.Simvastatin increases irisin concentrations in vivo and in vitro

  9. Insulin-like growth factor-1 and cardiotrophin 1 increase strength and mass of extraocular muscle in juvenile chicken.

    Science.gov (United States)

    Li, Tian; Wiggins, Larisa M; von Bartheld, Christopher S

    2010-05-01

    Insulin-like growth factor 1 (IGF1) and cardiotrophin 1 (CT1) are known to increase the strength of extraocular muscles in adult and embryonic animals, but no information is available for the early postnatal period, when strabismus treatment in humans is most urgent. Here the authors sought to determine whether these trophic factors strengthen juvenile maturing extraocular muscles and gain insight into mechanisms of force increase. After two injections of IGF1, CT1, or both with different dosages in posthatch chickens, the authors quantified five parameters of the superior oblique extraocular muscle at 2 weeks of age: contractile force, muscle mass, total myofiber area, myofiber diameter, and number of proliferating satellite cells labeled by bromodeoxyuridine. Treatment with IGF1, CT1, and combination of IGF1 and CT1 significantly increased contractile force by 14% to 22%. CT1 and combination treatment significantly increased muscle mass by 10% to 24%. IGF1/CT1 combination treatment did not have additive effects on strengthening muscles, compared with single-drug treatments. Myofiber area increased significantly with IGF1 and CT1 treatment in proximal, but not distal, parts of the muscle and this was due to increased fiber numbers or length (IGF1) or increased diameters of global layer myofibers (CT1). Trophic factors increased the number of proliferating (bromodeoxyuridine-labeled) satellite cells in proximal and middle segments of muscles. Exogenous IGF1 and CT1 strengthen extraocular muscles during maturation. They predominantly remodel the proximal segment of juvenile extraocular muscles. This information about muscle plasticity may aid the design of pharmacologic treatment of strabismus in children during the "critical period" of oculomotor maturation.

  10. Exercise before breakfast increases 24-h fat oxidation in female subjects.

    Directory of Open Access Journals (Sweden)

    Kaito Iwayama

    Full Text Available Exercise performed in a postprandial state does not increase 24-h fat oxidation of male and female subjects. Conversely, it has been shown in male subjects that exercise performed in a postabsorptive state increases 24-h fat oxidation compared with that in sedentary control and that with exercise trials performed after breakfast, lunch, or dinner. There is a paucity of study evaluating the effect of exercise performed in a postabsorptive state in female subjects.Nine young female subjects participated in indirect calorimetry measurement over 24-h using a room-size metabolic chamber in which subjects remained sedentary or performed 60 min exercise before breakfast at 50% of [Formula: see text]. Exercise was accompanied by an increase in energy intake to ensure that subjects were in a similar state of energy balance over 24 h for the two trials.Compared with the sedentary condition, exercise performed before breakfast increased 24-h fat oxidation (519 ± 37 vs. 400 ± 41 kcal/day. Time courses of relative energy balance differed between trials with transient negative energy balance observed before breakfast. The lowest values of relative energy balance observed during the 24-h calorimetry, i.e., transient energy deficit, were greater in exercise trials than in sedentary trials. The transient deficit in carbohydrate balance was also observed before breakfast, and magnitude of the deficit was greater in exercise trial compared to that of sedentary trial.Under energy-balanced conditions, exercise performed in a post-absorptive state increases 24-h fat oxidation in female subjects. The effect of exercise performed before breakfast can be attributed to nutritional state: a transient deficit in energy and carbohydrate at the end of exercise.

  11. Pro-inflammatory macrophages increase in skeletal muscle of high fat-fed mice and correlate with metabolic risk markers in humans

    DEFF Research Database (Denmark)

    Fink, Lisbeth N; Costford, Sheila R; Lee, Yun S

    2014-01-01

    In obesity, immune cells infiltrate adipose tissue. Skeletal muscle is the major tissue of insulin-dependent glucose disposal, and indices of muscle inflammation arise during obesity, but whether and which immune cells increase in muscle remain unclear.......In obesity, immune cells infiltrate adipose tissue. Skeletal muscle is the major tissue of insulin-dependent glucose disposal, and indices of muscle inflammation arise during obesity, but whether and which immune cells increase in muscle remain unclear....

  12. Acute exercise increases adipose tissue interstitial adiponectin concentration in healthy overweight and lean subjects

    DEFF Research Database (Denmark)

    Højbjerre, Lise; Rosenzweig, Mary; Dela, Flemming

    2007-01-01

    OBJECTIVE: We studied how an acute bout of exercise influences expression and concentration of adiponectin and regulators of adiponectin in adipose tissue and plasma. DESIGN AND METHODS: Eight overweight and eight lean males were examined by large-pore microdialysis in s.c. abdominal adipose tissue...... increased the SCAAT interstitial adiponectin concentration in both overweight and lean subjects and concentrations did not differ between groups. Plasma adiponectin did not increase during exercise and was similar in overweight and lean subjects. Adiponectin mRNA in SCAAT decreased during exercise...... and was similar in overweight and lean subjects. Surprisingly, the interstitial adiponectin concentration in SCAAT was only 20% of the plasma concentration. SCAAT interleukin-6 (IL-6) microdialyzate and plasma concentrations and SCAAT IL-6 mRNA increased during exercise in both groups. Tumor necrosis factor- (TNF...

  13. Multiple endocrine neoplasia 2B: Differential increase in enteric nerve subgroups in muscle and mucosa

    Science.gov (United States)

    Hutson, John M; Farmer, Pam J; Peck, Cristal J; Chow, Chung W; Southwell, Bridget R

    2017-01-01

    Multiple endocrine neoplasia 2B (MEN2B) is a rare syndrome caused by an activating mutation of the RET gene, leading to enteric gangliomatosis. This child presented with constipation at 1-mo old, was diagnosed with MEN2B by rectal biopsy at 4 mo, had thyroidectomy at 9 mo and a colectomy at 4 years. We studied the extent of neuronal and nerve fibre proliferation and which classes of enteric nerves are affected by examining the colon with multiple neuronal antibodies. Resected transverse colon was fixed, frozen, sectioned and processed for fluorescence immunohistochemistry labelling with antibodies against TUJ1, Hu, ChAT, NOS, VIP, SP and CGRP and cKit. Control transverse colon was from the normal margin of Hirschsprung (HSCR) colon (4-year-old) and a child with familial adenomatous polyposis (FAP, 12 year). Myenteric ganglia were increased in size to as wide as the circular muscle. There was a large increase in nerve cells and nerve fibres. ChAT-, NOS-, VIP- and SP-immunoreactive nerve fibres all increased in the myenteric ganglia. NOS-IR nerves preferentially increased in the muscle, while VIP and SP increased in submucosal ganglia and mucosal nerve fibres. The density of ICC was normal. RET overactivation in MEN2B lead to a large increase in intrinsic nerve fibres in the myenteric and submucosal ganglia, with a relative increase in NOS-IR nerve fibres in the circular muscle and VIP and SP in the submucosal ganglia and mucosa. The changes were associated with severe constipation resulting in colectomy at 4 years. PMID:28868184

  14. Blood flow restriction increases metabolic stress but decreases muscle activation during high-load resistance exercise.

    Science.gov (United States)

    Teixeira, Emerson L; Barroso, Renato; Silva-Batista, Carla; Laurentino, Gilberto C; Loenneke, Jeremy P; Roschel, Hamilton; Ugrinowitsch, Carlos; Tricoli, Valmor

    2018-01-01

    We investigated differences in metabolic stress (lactate) and muscle activation (electromyography; EMG) when high-load resistance exercise (HL) is compared with a condition in which blood flow restriction (BFR) is applied during the exercise or during the rest interval. Twelve participants performed HL with BFR during the intervals (BFR-I), during the set (BFR-S), and without BFR. Each condition consisted of 3 sets of 8 repetitions with knee extension at 70% of 1-repetition maximum. Lactate and root mean square (RMS) from the surface EMG of the vastus lateralis were calculated. Lactate increased in all protocols but was higher with BFR-I than with BFR-S and HL. RMS decreased under all conditions, with a larger effect size in BFR-I (1.47) than in BFR-S (0.66) and HL (0.59). BFR-I increases lactate, possibly as a result of reduced restoration of ATP. Muscle activation seems to be impacted by mechanical stress but may be reduced by metabolic stress. Muscle Nerve 57: 107-111, 2018. © 2017 Wiley Periodicals, Inc.

  15. Increasing taurine intake and taurine synthesis improves skeletal muscle function in the mdx mouse model for Duchenne muscular dystrophy.

    Science.gov (United States)

    Terrill, Jessica R; Pinniger, Gavin J; Graves, Jamie A; Grounds, Miranda D; Arthur, Peter G

    2016-06-01

    Duchenne muscular dystrophy (DMD) is a fatal muscle wasting disease associated with increased inflammation, oxidative stress and myofibre necrosis. Cysteine precursor antioxidants such as N-acetyl cysteine (NAC) and l-2-oxothiazolidine-4-carboxylate (OTC) reduce dystropathology in the mdx mouse model for DMD, and we propose this is via increased synthesis of the amino acid taurine. We compared the capacity of OTC and taurine treatment to increase taurine content of mdx muscle, as well as effects on in vivo and ex vivo muscle function, inflammation and oxidative stress. Both treatments increased taurine in muscles, and improved many aspects of muscle function and reduced inflammation. Taurine treatment also reduced protein thiol oxidation and was overall more effective, as OTC treatment reduced body and muscle weight, suggesting some adverse effects of this drug. These data suggest that increasing dietary taurine is a better candidate for a therapeutic intervention for DMD. Duchenne muscular dystrophy (DMD) is a fatal muscle wasting disease for which there is no widely available cure. Whilst the mechanism of loss of muscle function in DMD and the mdx mouse model are not fully understood, disruptions in intracellular calcium homeostasis, inflammation and oxidative stress are implicated. We have shown that protein thiol oxidation is increased in mdx muscle, and that the indirect thiol antioxidant l-2-oxothiazolidine-4-carboxylate (OTC), which increases cysteine availability, decreases pathology and increases in vivo strength. We propose that the protective effects of OTC are a consequence of conversion of cysteine to taurine, which has itself been shown to be beneficial to mdx pathology. This study compares the efficacy of taurine with OTC in decreasing dystropathology in mdx mice by measuring in vivo and ex vivo contractile function and measurements of inflammation and protein thiol oxidation. Increasing the taurine content of mdx muscle improved both in vivo and ex

  16. Mechanisms of quadriceps muscle weakness in knee joint osteoarthritis: the effects of prolonged vibration on torque and muscle activation in osteoarthritic and healthy control subjects.

    Science.gov (United States)

    Rice, David A; McNair, Peter J; Lewis, Gwyn N

    2011-01-01

    A consequence of knee joint osteoarthritis (OA) is an inability to fully activate the quadriceps muscles, a problem termed arthrogenic muscle inhibition (AMI). AMI leads to marked quadriceps weakness that impairs physical function and may hasten disease progression. The purpose of the present study was to determine whether γ-loop dysfunction contributes to AMI in people with knee joint OA. Fifteen subjects with knee joint OA and 15 controls with no history of knee joint pathology participated in this study. Quadriceps and hamstrings peak isometric torque (Nm) and electromyography (EMG) amplitude were collected before and after 20 minutes of 50 Hz vibration applied to the infrapatellar tendon. Between-group differences in pre-vibration torque were analysed using a one-way analysis of covariance, with age, gender and body mass (kg) as the covariates. If the γ-loop is intact, vibration should decrease torque and EMG levels in the target muscle; if dysfunctional, then torque and EMG levels should not change following vibration. One-sample t tests were thus undertaken to analyse whether percentage changes in torque and EMG differed from zero after vibration in each group. In addition, analyses of covariance were utilised to analyse between-group differences in the percentage changes in torque and EMG following vibration. Pre-vibration quadriceps torque was significantly lower in the OA group compared with the control group (P = 0.005). Following tendon vibration, quadriceps torque (P 0.299). Hamstrings torque and EMG amplitude were unchanged in both groups (all P > 0.204). The vibration-induced changes in quadriceps torque and EMG were significantly different between the OA and control groups (all P torque or EMG (all P > 0.554). γ-loop dysfunction may contribute to AMI in individuals with knee joint OA, partially explaining the marked quadriceps weakness and atrophy that is often observed in this population.

  17. Increased IGF-IEc expression and mechano-growth factor production in intestinal muscle of fibrostenotic Crohn's disease and smooth muscle hypertrophy

    OpenAIRE

    Li, Chao; Vu, Kent; Hazelgrove, Krystina; Kuemmerle, John F.

    2015-01-01

    The igf1 gene is alternatively spliced as IGF-IEa and IGF-IEc variants in humans. In fibrostenotic Crohn's disease, the fibrogenic cytokine TGF-β1 induces IGF-IEa expression and IGF-I production in intestinal smooth muscle and results in muscle hyperplasia and collagen I production that contribute to stricture formation. Mechano-growth factor (MGF) derived from IGF-IEc induces skeletal and cardiac muscle hypertrophy following stress. We hypothesized that increased IGF-IEc expression and MGF p...

  18. A comparison of abdominal muscle thickness changes after a lifting task in subjects with and without chronic low-back pain.

    Science.gov (United States)

    Seyed Hoseinpoor, Tahere; Kahrizi, Sedighe; Mobini, Bahram; Naji, Mohsen

    2015-03-01

    Using ultrasound imaging, the abdominal muscles' response to the back extensor muscle fatigue was assessed in subjects with chronic low-back pain (CLBP). Lumbar muscle fatigue is a common occurrence among workers. Alteration in motor coordination is one consequence of muscular fatigue. According to previous studies, CLBP subjects use their back and abdominal muscles in different ways, but questions remain about abdominal muscle responses to back muscle fatigue in CLBP patients. Thirteen CLBP patients and 15 healthy subjects participated in this study. The thickness of abdominal muscles-including transverse abdominis (TrA), internal oblique abdominis (IO), and external oblique abdominis (EO) muscles-was measured in standing position with and without axial loads before and after a lifting fatigue task. The results reveal a significant difference for the main effects of group on percentage of change in TrA thickness (F = 8.9, p = .004). Percentage of change in thickness of TrA was 10% greater in the CLBP group. Although IO thickness displayed greater percentage of change in the CLBP group, the difference between groups was not significant. Abdominal muscle behavior changes with back-muscle fatigue in both healthy and CLBP subjects, but responses were more exaggerated in CLBP patients. Ultrasound imaging technique can provide critical information about the effect of fatigue on spinal muscle activation and consequently about the stability of the spine. As a more applicable and easy technique, ergonomists can use ultrasound imaging in musculoskeletal system assessment in worker populations in future studies. © 2014, Human Factors and Ergonomics Society.

  19. Impaired TCA cycle flux in mitochondria in skeletal muscle from type 2 diabetic subjects

    DEFF Research Database (Denmark)

    Gaster, Michael; Nehlin, Jan O; Minet, Ariane D

    2012-01-01

    The diabetic phenotype is complex, requiring elucidation of key initiating defects. Recent research has shown that diabetic myotubes express a primary reduced tricarboxylic acid (TCA) cycle flux. A reduced TCA cycle flux has also been shown both in insulin resistant offspring of T2D patients...... and exercising T2D patients in vivo. This review will discuss the latest advances in the understanding of the molecular mechanisms regulating the TCA cycle with focus on possible underlying mechanism which could explain the impaired TCA flux in insulin resistant human skeletal muscle in type 2 diabetes....... A reduced TCA is both a marker and a maker of the diabetic phenotype....

  20. Gain-of-function R225W mutation in human AMPKgamma(3 causing increased glycogen and decreased triglyceride in skeletal muscle.

    Directory of Open Access Journals (Sweden)

    Sheila R Costford

    Full Text Available BACKGROUND: AMP-activated protein kinase (AMPK is a heterotrimeric enzyme that is evolutionarily conserved from yeast to mammals and functions to maintain cellular and whole body energy homeostasis. Studies in experimental animals demonstrate that activation of AMPK in skeletal muscle protects against insulin resistance, type 2 diabetes and obesity. The regulatory gamma(3 subunit of AMPK is expressed exclusively in skeletal muscle; however, its importance in controlling overall AMPK activity is unknown. While evidence is emerging that gamma subunit mutations interfere specifically with AMP activation, there remains some controversy regarding the impact of gamma subunit mutations. Here we report the first gain-of-function mutation in the muscle-specific regulatory gamma(3 subunit in humans. METHODS AND FINDINGS: We sequenced the exons and splice junctions of the AMPK gamma(3 gene (PRKAG3 in 761 obese and 759 lean individuals, identifying 87 sequence variants including a novel R225W mutation in subjects from two unrelated families. The gamma(3 R225W mutation is homologous in location to the gamma(2R302Q mutation in patients with Wolf-Parkinson-White syndrome and to the gamma(3R225Q mutation originally linked to an increase in muscle glycogen content in purebred Hampshire Rendement Napole (RN- pigs. We demonstrate in differentiated muscle satellite cells obtained from the vastus lateralis of R225W carriers that the mutation is associated with an approximate doubling of both basal and AMP-activated AMPK activities. Moreover, subjects bearing the R225W mutation exhibit a approximately 90% increase of skeletal muscle glycogen content and a approximately 30% decrease in intramuscular triglyceride (IMTG. CONCLUSIONS: We have identified for the first time a mutation in the skeletal muscle-specific regulatory gamma(3 subunit of AMPK in humans. The gamma(3R225W mutation has significant functional effects as demonstrated by increases in basal and AMP

  1. Increased carotid thickness in subjects with recently-diagnosed diabetes from rural Cameroon.

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    Nicola Napoli

    Full Text Available BACKGROUND: We have recently shown a high prevalence of diabetes and obesity in rural Cameroon, despite an improved lifestyle. Diabetes in rural Africa remains underdiagnosed and its role in increasing risk of atherosclerosis in these populations is unknown. We investigated the prevalence of carotid atherosclerosis and cardiovascular risk factors in a population of subjects with recently-diagnosed diabetes from rural Cameroon. METHODOLOGY/PRINCIPAL FINDINGS: In a case-control study, carotid intima-media thickness (IMT was measured in 74 subjects with diabetes (diagnosed 0.9 mm was found in 4%, 45.9% and 20% of diabetic subjects at the common, bulb or internal carotid, respectively. Only 25% of patients had an HbA1c9%. The prevalence of diabetic subjects with abnormal levels of LDL-cholesterol, triglycerides, HDL-cholesterol or blood pressure was 45%, 16.6%, 15% and 65.7%, respectively. CONCLUSIONS: Carotid thickness is increased in subjects with diabetes from a rural area of Cameroon, despite the relatively recent diagnosis. These findings and the high rate of uncontrolled diabetes in this population support the increasing concern of diabetes and cardiovascular diseases in African countries and indicate the need for multifaceted health interventions in urban and rural settings.

  2. Increased phosphorylation of skeletal muscle glycogen synthase at NH2-terminal sites during physiological hyperinsulinemia in type 2 diabetes

    DEFF Research Database (Denmark)

    Højlund, Kurt; Staehr, Peter; Hansen, Bo Falck

    2003-01-01

    In type 2 diabetes, insulin activation of muscle glycogen synthase (GS) is impaired. This defect plays a major role for the development of insulin resistance and hyperglycemia. In animal muscle, insulin activates GS by reducing phosphorylation at both NH(2)- and COOH-terminal sites, but the mecha......In type 2 diabetes, insulin activation of muscle glycogen synthase (GS) is impaired. This defect plays a major role for the development of insulin resistance and hyperglycemia. In animal muscle, insulin activates GS by reducing phosphorylation at both NH(2)- and COOH-terminal sites......, but the mechanism involved in human muscle and the defect in type 2 diabetes remain unclear. We studied the effect of insulin at physiological concentrations on glucose metabolism, insulin signaling and phosphorylation of GS in skeletal muscle from type 2 diabetic and well-matched control subjects during euglycemic......-hyperinsulinemic clamps. Analysis using phospho-specific antibodies revealed that insulin decreases phosphorylation of sites 3a + 3b in human muscle, and this was accompanied by activation of Akt and inhibition of glycogen synthase kinase-3alpha. In type 2 diabetic subjects these effects of insulin were fully intact...

  3. HIV Infection Is Associated with Increased Fatty Infiltration of the Thigh Muscle with Aging Independent of Fat Distribution.

    Directory of Open Access Journals (Sweden)

    Javzandulam Natsag

    Full Text Available Lower muscle density on computed tomography (CT provides a measure of fatty infiltration of muscle, an aspect of muscle quality that has been associated with metabolic abnormalities, weakness, decreased mobility, and increased fracture risk in older adults. We assessed the cross-sectional relationship between HIV serostatus, age, thigh muscle attenuation, and thigh muscle cross-sectional area (CSA.Mean CT-quantified Hounsfield units (HU of the thigh muscle bundle and CSA were evaluated in 368 HIV-infected and 145 HIV-uninfected men enrolled in the Multicenter AIDS Cohort Study (MACS Cardiovascular Substudy using multivariable linear regression. Models all were adjusted for HIV serostatus, age, race, and body mass index (BMI; each model was further adjusted for covariates that differed by HIV serostatus, including insulin resistance, hepatitis C, malignancy, smoking, alcohol use, and self-reported limitation in physical activity.HIV-infected men had greater thigh muscle CSA (p<0.001 but lower muscle density (p<0.001 compared to HIV-uninfected men. Muscle density remained lower in HIV-infected men (p = 0.001 when abdominal visceral adiposity, and thigh subcutaneous adipose tissue area were substituted for BMI in a multivariable model. Muscle density decreased by 0.16 HU per year (p<0.001 of increasing age among the HIV-infected men, but not in the HIV-uninfected men (HIV x age interaction -0.20 HU; p = 0.002.HIV-infected men had lower thigh muscle density compared to HIV-uninfected men, and a more pronounced decline with increasing age, indicative of greater fatty infiltration. These findings suggest that lower muscle quality among HIV-infected persons may be a risk factor for impairments in physical function with aging.

  4. Ischemic Conditioning Increases Strength and Volitional Activation of Paretic Muscle in Chronic Stroke: A Pilot Study.

    Science.gov (United States)

    Hyngstrom, Allison S; Murphy, Spencer A; Nguyen, Jennifer; Schmit, Brian D; Negro, Francesco; Gutterman, David D; Durand, Matthew J

    2018-02-08

    Ischemic conditioning (IC) on the arm or leg has emerged as an intervention to improve strength and performance in healthy populations, but the effects on neurologic populations are unknown. The purpose of this study was to quantify the effects of a single session of IC on knee extensor strength and muscle activation in chronic stroke survivors. Maximal knee extensor torque measurements and surface EMG were quantified in 10 chronic stroke survivors (>1 year post-stroke) with hemiparesis before and after a single session of IC or Sham on the paretic leg. IC consisted of five minutes of compression with a proximal thigh cuff (inflation pressure = 225 mmHg for IC or 25 mmHg for Sham) followed by five minutes of rest. This was repeated five times. Maximal knee extensor strength, EMG magnitude, and motor unit firing behavior were measured before and immediately after IC or Sham. IC increased paretic leg strength by 10.6{plus minus}8.5 Nm while no difference was observed in the Sham group (change in Sham = 1.3{plus minus}2.9 Nm; p = 0.001 IC vs. Sham). IC-induced increases in strength were accompanied by a 31{plus minus}15% increase in the magnitude of muscle EMG during maximal contractions and a 5% decrease in motor unit recruitment thresholds during sub-maximal contractions. Individuals who had the most asymmetry in strength between their paretic and non-paretic legs had the largest increases in strength (r 2 = 0.54). This study provides evidence that a single session of IC can increase strength through improved muscle activation in chronic stroke survivors.

  5. Chronic oral ingestion of l-carnitine and carbohydrate increases muscle carnitine content and alters muscle fuel metabolism during exercise in humans

    Science.gov (United States)

    Wall, Benjamin T; Stephens, Francis B; Constantin-Teodosiu, Dumitru; Marimuthu, Kanagaraj; Macdonald, Ian A; Greenhaff, Paul L

    2011-01-01

    We have previously shown that insulin increases muscle total carnitine (TC) content during acute i.v. l-carnitine infusion. Here we determined the effects of chronic l-carnitine and carbohydrate (CHO; to elevate serum insulin) ingestion on muscle TC content and exercise metabolism and performance in humans. On three visits, each separated by 12 weeks, 14 healthy male volunteers (age 25.9 ± 2.1 years, BMI 23.0 ± 0.8 kg m−2) performed an exercise test comprising 30 min cycling at 50%, 30 min at 80%, then a 30 min work output performance trial. Muscle biopsies were obtained at rest and after exercise at 50% and 80% on each occasion. Following visit one, volunteers ingested either 80 g of CHO (Control) or 2 g of l-carnitine-l-tartrate and 80 g of CHO (Carnitine) twice daily for 24 weeks in a randomised, double blind manner. All significant effects reported occurred after 24 weeks. Muscle TC increased from basal by 21% in Carnitine (P < 0.05), and was unchanged in Control. At 50%, the Carnitine group utilised 55% less muscle glycogen compared to Control (P < 0.05) and 31% less pyruvate dehydrogenase complex (PDC) activation compared to before supplementation (P < 0.05). Conversely, at 80%, muscle PDC activation was 38% higher (P < 0.05), acetylcarnitine content showed a trend to be 16% greater (P < 0.10), muscle lactate content was 44% lower (P < 0.05) and the muscle PCr/ATP ratio was better maintained (P < 0.05) in Carnitine compared to Control. The Carnitine group increased work output 11% from baseline in the performance trial, while Control showed no change. This is the first demonstration that human muscle TC can be increased by dietary means and results in muscle glycogen sparing during low intensity exercise (consistent with an increase in lipid utilisation) and a better matching of glycolytic, PDC and mitochondrial flux during high intensity exercise, thereby reducing muscle anaerobic ATP production. Furthermore, these changes were associated with an

  6. Increased Selenoprotein P Levels in Subjects with Visceral Obesity and Nonalcoholic Fatty Liver Disease

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    Hae Yoon Choi

    2013-02-01

    Full Text Available BackgroundSelenoprotein P (SeP has recently been reported as a novel hepatokine that regulates insulin resistance and systemic energy metabolism in rodents and humans. We explored the associations among SeP, visceral obesity, and nonalcoholic fatty liver disease (NAFLD.MethodsWe examined serum SeP concentrations in subjects with increased visceral fat area (VFA or liver fat accumulation measured with computed tomography. Our study subjects included 120 nondiabetic individuals selected from participants of the Korean Sarcopenic Obesity Study. In addition, we evaluated the relationship between SeP and cardiometabolic risk factors, including homeostasis model of insulin resistance (HOMA-IR, high sensitivity C-reactive protein (hsCRP, adiponectin values, and brachial-ankle pulse wave velocity (baPWV.ResultsSubjects with NAFLD showed increased levels of HOMA-IR, hsCRP, VFA, and several components of metabolic syndrome and decreased levels of adiponectin and high density lipoprotein cholesterol than those of controls. Serum SeP levels were positively correlated with VFA, hsCRP, and baPWV and negatively correlated with the liver attenuation index. Not only subjects with visceral obesity but also those with NAFLD exhibited significantly increased SeP levels (P<0.001. In multiple logistic regression analysis, the subjects in the highest SeP tertile showed a higher risk for NAFLD than those in the lowest SeP tertile, even after adjusting for potential confounding factors (odds ratio, 7.48; 95% confidence interval, 1.72 to 32.60; P=0.007.ConclusionCirculating SeP levels were increased in subjects with NAFLD as well as in those with visceral obesity and may be a novel biomarker for NAFLD.

  7. Electromyographic activity of erector spinae and external oblique muscles during trunk lateral bending and axial rotation in patients with adolescent idiopathic scoliosis and healthy subjects.

    Science.gov (United States)

    Farahpour, Nader; Younesian, Hananeh; Bahrpeyma, Farid

    2015-06-01

    The aim of this study was to analyze electrical activity of trunk muscles in adolescent idiopathic scoliosis patients and healthy subjects during trunk lateral bending and rotation movements. Ten patients with right thoracic scoliosis [Cobb angle: 29.1° (10.4°)] and 10 control adolescents were studied. Electrical activities of erector spinae muscle at 6th and 10th thoracic and 3rd lumbar vertebral level, and external oblique muscles were measured bilaterally during the right and left bending from standing and prone positions, and trunk rotation in sitting position. In trunk rotation to the right, the right-side external oblique (antagonist) muscle in scoliosis group was greater than that in control group (pscoliosis group, the antagonistic activity of EST6 muscle was greater than its agonistic activity (pscoliosis group was higher than that of control group (p=0.02). During the left bending from prone position, right-side EST6 and right-side ESL3 muscles of scoliosis group were greater than that of control group (pscoliosis group, the greater antagonistic activity of erector spinae muscle at 6th thoracic vertebral level than its agonistic activity, indicates that scoliosis is associated with asymmetrical muscle activity. Lateral bending from standing position is appropriate test to distinguish between scoliosis and control subjects. In scoliosis, the asymmetrical muscle activity is not an inherent characteristic since it was not displayed in all back motions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Overexpression of PGC-1α Increases Fatty Acid Oxidative Capacity of Human Skeletal Muscle Cells

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    Nataša Nikolić

    2012-01-01

    Full Text Available We investigated the effects of PGC-1α (peroxisome proliferator-activated receptor γ coactivator-1α overexpression on the oxidative capacity of human skeletal muscle cells ex vivo. PGC-1α overexpression increased the oxidation rate of palmitic acid and mRNA expression of genes regulating lipid metabolism, mitochondrial biogenesis, and function in human myotubes. Basal and insulin-stimulated deoxyglucose uptake were decreased, possibly due to upregulation of PDK4 mRNA. Expression of fast fiber-type gene marker (MHCIIa was decreased. Compared to skeletal muscle in vivo, PGC-1α overexpression increased expression of several genes, which were downregulated during the process of cell isolation and culturing. In conclusion, PGC-1α overexpression increased oxidative capacity of cultured myotubes by improving lipid metabolism, increasing expression of genes involved in regulation of mitochondrial function and biogenesis, and decreasing expression of MHCIIa. These results suggest that therapies aimed at increasing PGC-1α expression may have utility in treatment of obesity and obesity-related diseases.

  9. Children with low muscle strength are at an increased risk of fracture with exposure to exercise.

    Science.gov (United States)

    Clark, E M; Tobias, J H; Murray, L; Boreham, C

    2011-06-01

    To use objective measures of physical fitness and muscle function to assess the interplay between exercise, muscle and fractures during childhood. A cross-sectional analysis was performed using The Young Hearts Project, a population-based cohort recruited from Northern Ireland. Grip strength was assessed with a hand-held dynamometer. Aerobic fitness was assessed using the 20-metre endurance shuttle run. The outcome of interest was reported fractures. Data were also collected on other potential confounders. There were 787 boys (49.5%) and 803 girls aged 13.9±1.5 years. 414 (26.0%) children reported a fracture at anytime since birth. There was a positive association between higher aerobic fitness and reported fracture (OR 1.23, 95%CI 1.05 to 1.45, P=0.012) greatest in those with lowest grip strength (OR 2.10, 95%CI 1.23 to 3.31, P=0.005). Conversely, in those with highest grip strength, no association was seen between aerobic fitness and reported fractures. In children, higher levels of aerobic fitness are associated with an increased risk of fractures, with the greatest risk seen in those with low muscle strength. Our results suggest that there is the potential for exercise protocols that aim to strengthen forearm musculature to reduce upper limb fractures in adolescents.

  10. Prolonged constant load cycling exercise is associated with reduced gross efficiency and increased muscle oxygen uptake.

    Science.gov (United States)

    Hopker, J G; O'Grady, C; Pageaux, B

    2017-04-01

    This study investigated the effects of prolonged constant load cycling exercise on cycling efficiency and local muscle oxygen uptake responses. Fourteen well-trained cyclists each completed a 2-h steady-state cycling bout at 60% of their maximal minute power output to assess changes in gross cycling efficiency (GE) and muscle oxygen uptake (mVO 2 ) at time points 5, 30, 60, 90, and 120 min. Near-infrared spatially resolved spectroscopy (NIRS) was used to continually monitor tissue oxygenation of the Vastus Lateralis muscle, with arterial occlusions (OCC) applied to assess mVO 2 . The half-recovery time of oxygenated hemoglobin (HbO 2 ) was also assessed pre and post the 2-h cycling exercise by measuring the hyperemic response following a 5-min OCC. GE significantly declined during the 2-h cycling bout (18.4 ± 1.6 to 17.4 ± 1.4%; P cycling exercise (+7.1 ± 19s), albeit not significantly (d: 0.48; P = 0.27). This study demonstrates that GE decreases during prolonged constant load cycling exercise and provides evidence of an increased mVO 2 , suggestive of progressive mitochondrial or contractile inefficiency. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. Insulin stimulation of glucose transport activity in rat skeletal muscle: increase in cell surface GLUT4 as assessed by photolabelling.

    OpenAIRE

    Wilson, C. M.; Cushman, S W

    1994-01-01

    We have used a photoaffinity label to quantify cell surface GLUT4 glucose transporters in isolated rat soleus muscles. In this system, insulin stimulated an 8.6-fold increase in 3-O-methylglucose glucose transport, while photolabelled GLUT4 increased 8-fold. These results demonstrate that the insulin-stimulated increase in glucose transport activity in skeletal muscle can be accounted for by an increase in surface-accessible GLUT4 content.

  12. The Effectiveness of a Peer-Helping Programme That Increases Subjective Well-Being

    Science.gov (United States)

    Eryilmaz, Ali

    2017-01-01

    The present study aims to investigate the effectiveness of a peer-helping programme in increasing the subjective well-being of a group of university students compared with a control group with the same characteristics who did not receive the intervention. The intervention recipients consisted of 13 male and 17 female participants. The peer helpers…

  13. 86Rubidium uptake in mononuclear leucocytes from young subjects at increased risk of developing essential hypertension

    DEFF Research Database (Denmark)

    Nielsen, J R; Johansen, Torben; Pedersen, K E

    1988-01-01

    parents. 86Rubidium uptake was significantly increased in the borderline hypertensive subjects, especially in the borderline hypertensive offspring of hypertensive patients. Our results indicate that the sodium-potassium pump is activated in mononuclear leucocytes from borderline hypertensives......, and especially in those borderline hypertensives with at least one hypertensive parent. The latter group was also the group at greatest risk of developing essential hypertension....

  14. Insulin resistance in non-obese subjects is associated with activation of the JNK pathway and impaired insulin signaling in skeletal muscle.

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    Umesh B Masharani

    2011-05-01

    Full Text Available The pathogenesis of insulin resistance in the absence of obesity is unknown. In obesity, multiple stress kinases have been identified that impair the insulin signaling pathway via serine phosphorylation of key second messenger proteins. These stress kinases are activated through various mechanisms related to lipid oversupply locally in insulin target tissues and in various adipose depots.To explore whether specific stress kinases that have been implicated in the insulin resistance of obesity are potentially contributing to insulin resistance in non-obese individuals, twenty healthy, non-obese, normoglycemic subjects identified as insulin sensitive or resistant were studied. Vastus lateralis muscle biopsies obtained during euglycemic, hyperinsulinemic clamp were evaluated for insulin signaling and for activation of stress kinase pathways. Total and regional adipose stores and intramyocellular lipids (IMCL were assessed by DXA, MRI and (1H-MRS. In muscle of resistant subjects, phosphorylation of JNK was increased (1.36±0.23 vs. 0.78±0.10 OD units, P<0.05, while there was no evidence for activation of p38 MAPK or IKKβ. IRS-1 serine phosphorylation was increased (1.30±0.09 vs. 0.22±0.03 OD units, P<0.005 while insulin-stimulated tyrosine phosphorylation decreased (10.97±0.95 vs. 0.89±0.50 OD units, P<0.005. IMCL levels were twice as high in insulin resistant subjects (3.26±0.48 vs. 1.58±0.35% H(2O peak, P<0.05, who also displayed increased total fat and abdominal fat when compared to insulin sensitive controls.This is the first report demonstrating that insulin resistance in non-obese, normoglycemic subjects is associated with activation of the JNK pathway related to increased IMCL and higher total body and abdominal adipose stores. While JNK activation is consistent with a primary impact of muscle lipid accumulation on metabolic stress, further work is necessary to determine the relative contributions of the various mediators of impaired

  15. Decrease of muscle strength is associated with increase of activity limitations in early knee osteoarthritis: 3-year results from the cohort hip and cohort knee study.

    Science.gov (United States)

    van der Esch, Martin; Holla, Jasmijn F; van der Leeden, Marike; Knol, Dirk L; Lems, Willem F; Roorda, Leo D; Dekker, Joost

    2014-10-01

    To determine whether a decrease in muscle strength over 3 years is associated with an increase in activity limitations in persons with early symptomatic knee osteoarthritis (OA), and to examine whether the longitudinal association between muscle strength and activity limitations is moderated by knee joint proprioception and laxity. A longitudinal cohort study with 3-year follow-up. Measurements were performed at the second (t0) and fifth (t1) year of the Cohort Hip and Cohort Knee (CHECK) study. Statistical analyses included paired t tests, chi-square tests, and regression analyses. In regression analyses, the association between muscle strength and activity limitations was adjusted for confounders. A rehabilitation and rheumatology center. Subjects (N=146) with early symptomatic knee OA from the CHECK study. Not applicable. Muscle strength, proprioception, and laxity were assessed using specifically designed measurement devices. Self-reported and performance-based activity limitations were measured with the Western Ontario and McMaster Universities Osteoarthritis Index, the Get Up and Go test, the walk test, and the stair-climb test. A total of 116 women (79.5%) and 30 men (20.5%), with a mean age ± SD of 58.4±4.9 years and a mean body mass index ± SD of 25.5±3.6, were included in the study. Overall, small 3-year changes in muscle strength and activity limitations were observed. At the group level, the average muscle strength increased by 10% (1.0±0.3 to 1.1±0.3Nm/kg) over the 3 years. The 3-year decrease in muscle strength was independently associated with an increase in performance-based activity limitations on all 3 measures (B=-1.12, B=-5.83, and B=-1.25, respectively). Proprioception and laxity did not moderate this association. In patients with early knee OA, decreased muscle strength is associated with an increase in activity limitations. Our results are a step toward understanding the role of muscle weakness in the development of activity limitations

  16. Two weeks of muscle immobilization impairs functional sympatholysis but increases exercise hyperemia and the vasodilatory responsiveness to infused ATP

    DEFF Research Database (Denmark)

    Mortensen, Stefan P; Mørkeberg, Jakob S; Thaning, Pia

    2012-01-01

    with immobilization. These results suggest that muscle inactivity impairs functional sympatholysis and that the magnitude of hyperemia and blood pressure response to exercise is dependent on the training status of the muscle. Immobilization also increases the vasodilatory response to infused ATP....

  17. Medial gastrocnemius muscle growth during adolescence is mediated by increased fascicle diameter rather than by longitudinal fascicle growth.

    Science.gov (United States)

    Weide, Guido; Huijing, Peter A; Maas, Josina C; Becher, Jules G; Harlaar, Jaap; Jaspers, Richard T

    2015-06-01

    Using a cross-sectional design, the purpose of this study was to determine how pennate gastrocnemius medialis (GM) muscle geometry changes as a function of adolescent age. Sixteen healthy adolescent males (aged 10-19 years) participated in this study. GM muscle geometry was measured within the mid-longitudinal plane obtained from a 3D voxel-array composed of transverse ultrasound images. Images were taken at footplate angles corresponding to standardised externally applied footplate moments (between 4 Nm plantar flexion and 6 Nm dorsal flexion). Muscle activity was recorded using surface electromyography (EMG), expressed as a percentage of maximal voluntary contraction (%MVC). To minimise the effects of muscle excitation, EMG inclusion criteria were set at muscle (belly) length increased due to an increase in the length component of the physiological cross-sectional area measured within the mid-longitudinal plane. No difference was found between fascicles at different ages, but the aponeurosis length and pennation angle increased by 0.5 cm year(-1) and 0.5° per year, respectively. Footplate angles corresponding to externally applied 0 and 4 Nm plantarflexion moments were not associated with different adolescent ages. In contrast, footplate angles corresponding to externally applied 4 and 6 Nm dorsal flexion moments decreased by 10° between 10 and 19 years. In conclusion, we found that in adolescents' pennate GM muscles, longitudinal muscle growth is mediated predominantly by increased muscle fascicle diameter. © 2015 Anatomical Society.

  18. Increased muscle tension and reduced elasticity of affected muscles in recent-onset Graves' disease caused primarily by active muscle contraction

    NARCIS (Netherlands)

    H.J. Simonsz (Huib); G. Kommerell (Guntram)

    1989-01-01

    textabstractIn 3 patients with Graves' disease of recent onset, length-tension diagrams were made during surgery for squint under eyedrop anesthesia. The affected muscles were found to be very stiff when the other eye looked straight ahead. It was expected that these stiff muscles would be able to

  19. [Magnetic resonance imaging assessment of the lateral pterygoid muscle in Class III malocclusion subjects].

    Science.gov (United States)

    Liu, Yue-hua; Yang, Xiao-jiang; Gao, Xiao-hui; Li, Yuan

    2012-01-01

    To analyze the relationship between Class III malocclusion and pathological changes in temporomandibular joint (TMJ) structures using magnetic resenonce imaging (MRI). Twenty-four Class III malocclusion adult patients and 10 normal control cases were included in the study. The characteristics of lateral pertygoid muscle (LPM) in the sample group and the control group were assessed. More pathological changes of LPM were found in Class III malocclusion adult patients (36 TMJ). The changes included hypertrophy, atrophy and contracture. And there was no relation between the pathological changes of LPM and the symptom of temporomandibular disorders (TMD). The frequency of pathological changes of LPM was greater in patients with Class III malocclusion than in the control group.

  20. Increased prolactin levels are associated with impaired processing speed in subjects with early psychosis.

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    Itziar Montalvo

    Full Text Available Hyperprolactinaemia, a common side effect of some antipsychotic drugs, is also present in drug-naïve psychotic patients and subjects at risk for psychosis. Recent studies in non-psychiatric populations suggest that increased prolactin may have negative effects on cognition. The aim of our study was to explore whether high plasma prolactin levels are associated with poorer cognitive functioning in subjects with early psychoses. We studied 107 participants: 29 healthy subjects and 78 subjects with an early psychosis (55 psychotic disorders with <3 years of illness, 23 high-risk subjects. Cognitive assessment was performed with the MATRICS Cognitive Consensus Cognitive Battery, and prolactin levels were determined as well as total cortisol levels in plasma. Psychopathological status was assessed and the use of psychopharmacological treatments (antipsychotics, antidepressants, benzodiazepines recorded. Prolactin levels were negatively associated with cognitive performance in processing speed, in patients with a psychotic disorder and high-risk subjects. In the latter group, increased prolactin levels were also associated with impaired reasoning and problem solving and poorer general cognition. In a multiple linear regression analysis conducted in both high-risk and psychotic patients, controlling for potential confounders, prolactin and benzodiazepines were independently related to poorer cognitive performance in the speed of processing domain. A mediation analysis showed that both prolactin and benzodiazepine treatment act as mediators of the relationship between risperidone/paliperidone treatment and speed of processing. These results suggest that increased prolactin levels are associated with impaired processing speed in early psychosis. If these results are confirmed in future studies, strategies targeting reduction of prolactin levels may improve cognition in this population.

  1. Treatment of human muscle cells with popular dietary supplements increase mitochondrial function and metabolic rate

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    Vaughan Roger A

    2012-11-01

    Full Text Available Abstract Background Obesity is a common pathology with increasing incidence, and is associated with increased mortality and healthcare costs. Several treatment options for obesity are currently available ranging from behavioral modifications to pharmaceutical agents. Many popular dietary supplements claim to enhance weight loss by acting as metabolic stimulators, however direct tests of their effect on metabolism have not been performed. Purpose This work identified the effects popular dietary supplements on metabolic rate and mitochondrial biosynthesis in human skeletal muscle cells. Methods Human rhabdomyosarcoma cells were treated with popular dietary supplements at varied doses for 24 hours. Peroxisome proliferator-activated receptor coactivator 1 alpha (PGC-1α, an important stimulator of mitochondrial biosynthesis, was quantified using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR. Mitochondrial content was measured using flow cytometry confirmed with confocal microscopy. Glycolytic metabolism was quantified by measuring extracellular acidification rate (ECAR and oxidative metabolism was quantified by measuring oxygen consumption rate (OCR. Total relative metabolism was quantified using WST-1 end point assay. Results Treatment of human rhabdomyosarcoma cells with dietary supplements OxyElite Pro (OEP or Cellucore HD (CHD induced PGC-1α leading to significantly increased mitochondrial content. Glycolytic and oxidative capacities were also significantly increased following treatment with OEP or CHD. Conclusion This is the first work to identify metabolic adaptations in muscle cells following treatment with popular dietary supplements including enhanced mitochondrial biosynthesis, and glycolytic, oxidative and total metabolism.

  2. Meat Science and Muscle Biology Symposium: manipulating meat tenderness by increasing the turnover of intramuscular connective tissue.

    Science.gov (United States)

    Purslow, P P; Archile-Contreras, A C; Cha, M C

    2012-03-01

    Controlled reduction of the connective tissue contribution to cooked meat toughness is an objective that would have considerable financial impact in terms of added product value. The amount of intramuscular connective tissue in a muscle appears connected to its in vivo function, so reduction of the overall connective tissue content is not thought to be a viable target. However, manipulation of the state of maturity of the collagenous component is a biologically viable target; by increasing connective tissue turnover, less mature structures can be produced that are functional in vivo but more easily broken down on cooking at temperatures above 60°C, thus improving cooked meat tenderness. Recent work using cell culture models of fibroblasts derived from muscle and myoblasts has identified a range of factors that alter the activity of the principal enzymes responsible for connective tissue turnover, the matrix metalloproteinases (MMP). Fibroblasts cultured from 3 different skeletal muscles from the same animal show different cell proliferation and MMP activity, which may relate to the different connective tissue content and architecture in functionally different muscles. Expression of MMP by fibroblasts is increased by vitamins that can counter the negative effects of oxidative stress on new collagen synthesis. Preliminary work using in situ zymography of myotubes in culture also indicates increased MMP activity in the presence of epinephrine and reactive oxidative species. Comparison of the relative changes in MMP expression from muscle cells vs. fibroblasts shows that myoblasts are more responsive to a range of stimuli. Muscle cells are likely to produce more of the total MMP in muscle tissue as a whole, and the expression of latent forms of the enzymes (i.e., pro-MMP) may vary between oxidative and glycolytic muscle fibers within the same muscle. The implication is that the different muscle fiber composition of different muscles eaten as meat may influence the

  3. The Reticulospinal Pathway Does Not Increase Its Contribution to the Strength of Contralesional Muscles in Stroke Survivors as Compared to Ipsilesional Side or Healthy Controls

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    Sheng Li

    2017-11-01

    Full Text Available ObjectiveStartling acoustic stimulation (SAS, via activation of reticulospinal (RS pathways, has shown to increase muscle strength in healthy subjects. We hypothesized that, given RS hyperexcitability in stroke survivors, SAS could increase muscle strength in stroke survivors. The objective was to quantify the effect of SAS on maximal and sub-maximal voluntary elbow flexion on the contralesional (impaired side in stroke survivors as compared to ipsilesional (non-impaired side and healthy controls.DesignThirteen hemiparetic stroke survivors and 12 healthy subjects volunteered for this investigation. Acoustic stimulation was given at rest, during ballistic maximal and sustained sub-maximal isometric elbow contractions using low (80 dB and high intensity sound (105 dB. The effect of acoustic stimuli was evaluated from EMG and force recordings.ResultsPrevalence of acoustic startle reflex with shorter latency in the impaired biceps was greater as compared to the response in the non-impaired side of stroke subjects and in healthy subjects. Delivery of SAS resulted in earlier initiation of elbow flexion and greater peak torque in healthy subjects and in stroke subjects with spastic hemiplegia during maximal voluntary elbow flexion tasks. During sub-maximal elbow flexion tasks, SAS-induced force responses were slightly greater on the impaired side than the non-impaired side. However, no statistically significant difference was found in SAS-induced responses between impaired and non-impaired sides at maximal and sub-maximal elbow flexion tasks.ConclusionThe findings suggest RS hyperexcitability in stroke survivors with spastic hemiplegia. The results of similar SAS-induced responses between healthy and stroke subjects indicate that RS projections via acoustic stimulation are not likely to contribute to muscle strength for stroke survivors to a significant extent.

  4. High-fat feeding inhibits exercise-induced increase in mitochondrial respiratory flux in skeletal muscle

    DEFF Research Database (Denmark)

    Skovbro, Mette; Boushel, Robert Christopher; Hansen, Christina Neigaard

    2011-01-01

    ) and intramyocellular triacylglycerol content did not change with the intervention in either group. Indexes of mitochondrial density were similar across the groups and intervention. Mitochondrial respiratory rates, measured in permeabilized muscle fibers, showed a 31 ± 11 and 26 ± 9% exercise-induced increase (P ... and in exercise-induced mitochondrial substrate oxidation rates, with the effects being present hours after the exercise. The effect of HFD is present even without effects on insulin sensitivity and intramyocellular lipid accumulation. An isocaloric high-fat diet does not cause insulin resistance....

  5. Abdominal Muscle Activity during Mechanical Ventilation Increases Lung Injury in Severe Acute Respiratory Distress Syndrome.

    Directory of Open Access Journals (Sweden)

    Xianming Zhang

    Full Text Available It has proved that muscle paralysis was more protective for injured lung in severe acute respiratory distress syndrome (ARDS, but the precise mechanism is not clear. The purpose of this study was to test the hypothesis that abdominal muscle activity during mechanically ventilation increases lung injury in severe ARDS.Eighteen male Beagles were studied under mechanical ventilation with anesthesia. Severe ARDS was induced by repetitive oleic acid infusion. After lung injury, Beagles were randomly assigned into spontaneous breathing group (BIPAPSB and abdominal muscle paralysis group (BIPAPAP. All groups were ventilated with BIPAP model for 8h, and the high pressure titrated to reached a tidal volume of 6ml/kg, the low pressure was set at 10 cmH2O, with I:E ratio 1:1, and respiratory rate adjusted to a PaCO2 of 35-60 mmHg. Six Beagles without ventilator support comprised the control group. Respiratory variables, end-expiratory volume (EELV and gas exchange were assessed during mechanical ventilation. The levels of Interleukin (IL-6, IL-8 in lung tissue and plasma were measured by qRT-PCR and ELISA respectively. Lung injury scores were determined at end of the experiment.For the comparable ventilator setting, as compared with BIPAPSB group, the BIPAPAP group presented higher EELV (427±47 vs. 366±38 ml and oxygenation index (293±36 vs. 226±31 mmHg, lower levels of IL-6(216.6±48.0 vs. 297.5±71.2 pg/ml and IL-8(246.8±78.2 vs. 357.5±69.3 pg/ml in plasma, and lower express levels of IL-6 mRNA (15.0±3.8 vs. 21.2±3.7 and IL-8 mRNA (18.9±6.8 vs. 29.5±7.9 in lung tissues. In addition, less lung histopathology injury were revealed in the BIPAPAP group (22.5±2.0 vs. 25.2±2.1.Abdominal muscle activity during mechanically ventilation is one of the injurious factors in severe ARDS, so abdominal muscle paralysis might be an effective strategy to minimize ventilator-induce lung injury.

  6. Abdominal Muscle Activity during Mechanical Ventilation Increases Lung Injury in Severe Acute Respiratory Distress Syndrome

    Science.gov (United States)

    Zhang, Xianming; Wu, Weiliang; Zhu, Yongcheng; Jiang, Ying; Du, Juan; Chen, Rongchang

    2016-01-01

    Objective It has proved that muscle paralysis was more protective for injured lung in severe acute respiratory distress syndrome (ARDS), but the precise mechanism is not clear. The purpose of this study was to test the hypothesis that abdominal muscle activity during mechanically ventilation increases lung injury in severe ARDS. Methods Eighteen male Beagles were studied under mechanical ventilation with anesthesia. Severe ARDS was induced by repetitive oleic acid infusion. After lung injury, Beagles were randomly assigned into spontaneous breathing group (BIPAPSB) and abdominal muscle paralysis group (BIPAPAP). All groups were ventilated with BIPAP model for 8h, and the high pressure titrated to reached a tidal volume of 6ml/kg, the low pressure was set at 10 cmH2O, with I:E ratio 1:1, and respiratory rate adjusted to a PaCO2 of 35–60 mmHg. Six Beagles without ventilator support comprised the control group. Respiratory variables, end-expiratory volume (EELV) and gas exchange were assessed during mechanical ventilation. The levels of Interleukin (IL)-6, IL-8 in lung tissue and plasma were measured by qRT-PCR and ELISA respectively. Lung injury scores were determined at end of the experiment. Results For the comparable ventilator setting, as compared with BIPAPSB group, the BIPAPAP group presented higher EELV (427±47 vs. 366±38 ml) and oxygenation index (293±36 vs. 226±31 mmHg), lower levels of IL-6(216.6±48.0 vs. 297.5±71.2 pg/ml) and IL-8(246.8±78.2 vs. 357.5±69.3 pg/ml) in plasma, and lower express levels of IL-6 mRNA (15.0±3.8 vs. 21.2±3.7) and IL-8 mRNA (18.9±6.8 vs. 29.5±7.9) in lung tissues. In addition, less lung histopathology injury were revealed in the BIPAPAP group (22.5±2.0 vs. 25.2±2.1). Conclusion Abdominal muscle activity during mechanically ventilation is one of the injurious factors in severe ARDS, so abdominal muscle paralysis might be an effective strategy to minimize ventilator-induce lung injury. PMID:26745868

  7. Bilateral differences in muscle architecture and increased rate of injury in national basketball association players.

    Science.gov (United States)

    Mangine, Gerald T; Hoffman, Jay R; Gonzalez, Adam M; Jajtner, Adam R; Scanlon, Tyler; Rogowski, Joseph P; Wells, Adam J; Fragala, Maren S; Stout, Jeffrey R

    2014-01-01

    sample, lower extremity side-to-side differences may be related to an increased risk for lower extremity injury. Future researchers using larger sample sizes need to identify normal versus at-risk ranges for bilateral differences in muscle structure and power of the lower extremities of professional basketball players and athletes in other sports.

  8. Bilateral Differences in Muscle Architecture and Increased Rate of Injury in National Basketball Association Players

    Science.gov (United States)

    Mangine, Gerald T.; Hoffman, Jay R.; Gonzalez, Adam M.; Jajtner, Adam R.; Scanlon, Tyler; Rogowski, Joseph P.; Wells, Adam J.; Fragala, Maren S.; Stout, Jeffrey R.

    2014-01-01

    ), these differences were not statistically significant (P = .20). Conclusions In the present sample, lower extremity side-to-side differences may be related to an increased risk for lower extremity injury. Future researchers using larger sample sizes need to identify normal versus at-risk ranges for bilateral differences in muscle structure and power of the lower extremities of professional basketball players and athletes in other sports. PMID:25322345

  9. Two-week inhalation of budesonide increases muscle Na,K ATPase content but not endurance in response to terbutaline in men.

    Science.gov (United States)

    Hostrup, M; Jessen, S; Onslev, J; Clausen, T; Porsbjerg, C

    2017-07-01

    While chronic systemic administration of glucocorticoids increases muscle Na+ ,K+ ATPase content, such effect is unexplored after therapeutic inhalation. We investigated the effect of therapeutic inhalation of the glucocorticoid budesonide on Na+ ,K+ ATPase content of skeletal muscle in men. Ten healthy trained subjects, aged 23 ± 4 years (mean ± 95% CI), participated in the study. Before and after 2 weeks of daily inhalation of budesonide (1.6 mg/day), a biopsy was taken from the vastus lateralis muscle for measurement of Na+ ,K+ ATPase content and blood samples were drawn for determination of plasma budesonide, cortisol, and K+ . Subjects' performance during cycling to fatigue at 90% of incremental peak power output (iPPO) was measured in response to 4 mg inhaled terbutaline to maximally stimulate Na+ ,K+ ATPase activity. Plasma concentrations of budesonide rose to 5.0 ± 1.6 nM with the intervention, whereas no changes were observed in plasma cortisol. Muscle Na+ ,K+ ATPase content increased (P ≤ 0.01) by 46 ± 34 pmol/(g wet wt) (17% increase) with the intervention. Cycling performance at 90% of iPPO did not change (P = 0.21) with the intervention (203 vs 214 s) in response to terbutaline. The present observations show that therapeutic inhalation of glucocorticoids increases muscle Na+ ,K+ ATPase content, but does not enhance high-intensity cycling endurance in response to terbutaline. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Electrostimulation to Increase Peroneal Muscle Strength in Pediatric Patients With Postsurgical Clubfoot

    Directory of Open Access Journals (Sweden)

    Guadalupe Morales-Osorio

    2016-01-01

    Full Text Available Background: Idiopathic congenital clubfoot is a deformity with various components. Its treatment can be conservative and or surgical in order to eliminate the deformity and to obtain a pain-free foot allowing for adequate mobility. Objectives: Our objective was to evaluate whether neuromuscular electrostimulation is useful for improving peroneal muscle strength in post-operative congenital clubfoot in children. Patients and Methods: An experimental, prospective, longitudinal, and comparative study was carried out on 10 patients with congenital clubfoot in the experimental group, and on 10 for historical controls. Initial and post-treatment clinical evaluations were conducted on patients in both groups. Surface electromyography (SEMG was used for the experimental group; each patient received 30 sessions of treatment with neuromuscular electrostimulation in order to obtain muscular contraction. Results: In both groups, there were more males with the average age or 5.5 years (ranging from 3 to 8 years of age. Peroneal muscular strength evaluated through the Daniels and Worthingham’s test increased post-treatment only in the experimental group, and comparing these results to those of the historical group, a significance level of P = 0.001 was obtained. The motor unit potential amplitude in the SEMG increased in the experimental group with a significance level of P < 0.05. Conclusions: Neuromuscular electrostimulation can be used to increase muscle strength, and it is a safe and painless treatment.

  11. Comparison of Inspiratory Muscle Strength Training Effects Between Older Subjects With and Without Chronic Obstructive Pulmonary Disease

    Directory of Open Access Journals (Sweden)

    Chien-Hui Huang

    2011-08-01

    Conclusion: IMST increases maximal inspiratory pressure, relieves dyspnea and improves health-related quality of life in older adults. IMST especially improves functional status in subjects without COPD. IMST benefits subjects with COPD and those without COPD. Therefore, IMST as a treatment tool is not confined to patients with COPD.

  12. Assessment of foetal wellbeing in pregnant women subjected to pelvic floor muscle training: a controlled randomised study.

    Science.gov (United States)

    Okido, Marcos Massaru; Valeri, Fabiana Lellis; Martins, Wellington Paula; Ferreira, Cristine Homsi Jorge; Duarte, Geraldo; Cavalli, Ricardo Carvalho

    2015-10-01

    The objective was to assess foetal wellbeing in pregnant women subjected to pelvic floor muscle training (PFMT) by evaluating the acute and chronic effects of the procedure using the Doppler method. Ninety-six primigravidae with singleton pregnancies and at a low risk of pregnancy complications were randomised to either intervention with PFMT or no intervention. The final analysis included 26 women in the intervention group and 33 in the control group. Women from the intervention group were subjected to a daily PFMT program. Evidence of possible foetal risk was assessed by Doppler and the control group received standard care. The protocol was conducted from 20 to 36 weeks' gestation. The pulsatility indices (PI) of the uterine, umbilical and middle cerebral arteries were determined at 28, 32 and 36 weeks' gestation. The acute effects were determined by comparing the values obtained before and after exercise in the group subjected to PFMT and the chronic effects were determined by comparing the resting values of the trained group with those of the control group. The results obtained showed normal values for the three gestational ages in both groups, with no difference between groups. Comparison before and after exercise showed a significant decline in the PI of uterine artery at 36 weeks without changes in the flow of umbilical and middle cerebral arteries. Pelvic floor muscle training in low-risk primigravidae with singleton pregnancies was associated with a significant decline in PI of the uterine artery after exercise, while no significant changes in the flow of the middle cerebral and umbilical arteries were found. The PFMT may be recommended to women as a first-line measure to prevent of urinary incontinence during pregnancy.

  13. Long-term endurance training increases serum cathepsin S levels in healthy female subjects.

    Science.gov (United States)

    Sponder, M; Minichsdorfer, C; Campean, I-A; Emich, M; Fritzer-Szekeres, M; Litschauer, B; Strametz-Juranek, J

    2017-11-27

    Circulating cathepsin S (CS) has been associated with a lower risk for breast cancer in a large Swedish cohort. Long-term physical activity has been shown to have beneficial effects on the development of various cancer subtypes, in particular breast and colorectal cancers. The aim of this study was to investigate the effect of long-term endurance sport on CS levels in females. Thirty-six of 40 subjects completed the study. Subjects were told to increase their activity pensum for 8 months reaching 150 min/week moderate or 75 min/week intense exercise. Ergometries were performed at the beginning and the end of the study to prove/quantify the performance gain. Blood samples were drawn at baseline and every 2 months. Serum CS levels were measured by ELISA. To analyse the change and the progression of CS, Wilcoxon rank sum and Friedman tests were used. The sportive group (performance gain by > 4.9%) showed a significant increase of CS levels from 3.32/2.73/4.09 to 4.00/3.09/5.04 ng/ml (p = 0.008) corresponding to an increase of 20.5%. We could show a significant increase of circulating CS levels in healthy female subjects induced by long-term physical activity. CS, occurring in the tumour microenvironment, is well-known to promote tumour growth, e.g. by ameliorating angiogenesis. However, the role of circulating CS in cancer growth is not clear. As physical activity is known as preventive intervention, in particular concerning breast and colorectal cancers, and long-term physical activity leads to an increase of CS levels in female subjects, circulating CS might even be involved in this protective effect. Clinical trial registration: NCT02097199.

  14. Transient increase in HDL-cholesterol during weight gain by hyperalimentation in healthy subjects.

    Science.gov (United States)

    Lindström, Torbjörn; Kechagias, Stergios; Carlsson, Martin; Nystrom, Fredrik H

    2011-04-01

    Determination of lipid levels is fundamental in cardiovascular risk assessment. We studied the short-term effects of fast food-based hyperalimentation on lipid levels in healthy subjects. Twelve healthy men and six healthy women with a mean age of 26 ± 6.6 years and an aged-matched control group were recruited for this prospective interventional study. Subjects in the intervention group aimed for a body weight increase of 5-15% by doubling the baseline caloric intake by eating at least two fast food-based meals a day in combination with adoption of a sedentary lifestyle for 4 weeks. This protocol induced a weight gain from 67.6 ± 9.1 kg to 74.0 ± 11 kg (P cholesterol occurred in all subjects during the study and this was apparent already at the first week in 16/18 subjects (mean increase at week 1: +22.0 ± 16%, range from -7 to +50%), whereas the highest level of HDL during the study as compared with baseline values varied from +6% to +58% (mean +31.6 ± 15%). The intake of saturated fat in the early phase of the trial related positively with the HDL-cholesterol-increase in the second week (r = 0.53, P = 0.028). Although the levels of insulin doubled at week 2, the increase in low-density lipoprotein (LDL)-cholesterol was only +12 ± 17%, and there was no statistically significant changes in fasting serum triglycerides. We conclude that hyperalimentation can induce a fast but transient increase in HDL-cholesterol that is of clinical interest when estimating cardiovascular risk based on serum lipid levels.

  15. Inhaled vs. oral alprazolam: subjective, behavioral and cognitive effects, and modestly increased abuse potential.

    Science.gov (United States)

    Reissig, Chad J; Harrison, Joseph A; Carter, Lawrence P; Griffiths, Roland R

    2015-03-01

    Infrahuman and human studies suggest that a determinant of the abuse potential of a drug is rate of onset of subjective effects. This study sought to determine if the rate of onset of subjective effects and abuse potential of alprazolam would be increased when administered via inhalation vs. the oral route. Placebo, inhaled alprazolam (0.5, 1, and 2 mg), and oral alprazolam (1, 2, and 4 mg) were administered under double-blind, double-dummy conditions using a crossover design in 14 healthy participants with histories of drug abuse. Participant and observer ratings and behavioral and cognitive performance measures were assessed repeatedly during 9-h sessions. Both routes of administration produced orderly dose and time-related effects, with higher doses producing greater and longer-lasting effects. Onset of subjective effects following inhaled alprazolam was very rapid (e.g., 2 vs. 49 min after 2 mg inhaled vs. oral). On measures of abuse potential (e.g., liking and good effects), inhaled alprazolam was more potent, as evidenced by a leftward shift in the dose-response curve. Despite the potency difference, at the highest doses, peak ratings of subjective effects related to abuse potential (e.g., "drug liking") were similar across the two routes. On other measures (e.g., sedation and performance), the routes were equipotent. The inhaled route of administration modestly increased the abuse potential of alprazolam despite significantly increasing its rate of onset. If marketed, the reduced availability and increased cost of inhaled alprazolam may render the societal risk of increased abuse to be low.

  16. Pelvic floor muscle training program increases muscular contractility during first pregnancy and postpartum: electromyographic study.

    Science.gov (United States)

    Marques, Joseane; Botelho, Simone; Pereira, Larissa Carvalho; Lanza, Ana Helena; Amorim, Cesar Ferreira; Palma, Paulo; Riccetto, Cassio

    2013-09-01

    The aim of this study was to evaluate the effect of a training program over both pelvic floor muscles contractility and urinary symptoms in primigravid pregnant and postpartum primiparous women. A clinical, prospective and blinded trial was conducted with 33 women divided into three groups: (G1) 13 primigravid pregnant women; (G2) 10 postpartum primiparous women (49.3 ± 5.84 days), after vaginal delivery with right mediolateral episiotomy; (G3) 10 postpartum primiparous women (46.3 ± 3.6 days), after cesarean section delivery. The evaluation was carried out using digital palpation (Modified Oxford Grading Scale), pelvic floor electromyography and, for the investigation of urinary symptoms, validated questionnaires (International Consultation on Incontinence Questionnaire-short form-ICIQ-UI SF and International Consultation on Incontinence Questionnaire Overactive Bladder-ICIQ-OAB). The protocol consisted of 10 individual sessions carried out by the physiotherapist through home visits, three times a week, with 60 min duration each. The statistical analysis was performed using ANOVA and Spearman's correlation coefficient. The pelvic floor muscle contractility increased after the training program (P = 0.0001) for all groups. Decreases in the scores of both ICIQ-UI SF (P = 0.009) and ICIQ-OAB (P = 0.0003) were also observed after training. Pelvic floor muscle training is an effective means for the increase in its own contractility in both primigravid pregnant and primiparous postpartum women, accompanied with a concomitant decrease in urinary symptoms. Copyright © 2012 Wiley Periodicals, Inc.

  17. The Effect of Dry Needling on Range of Motion of Neck Lateral Flexion in Subjects With Active Trigger Point in Upper Trapezius Muscle

    Directory of Open Access Journals (Sweden)

    Ziaeifar

    2014-12-01

    Full Text Available Background Myofascial trigger point is one of the most common causes of musculoskeletal disorders. Myofascial trigger point in upper trapezius has been reported as a symptom in patients with neck and upper thoracic pain. Objectives The purpose of this study was to investigate the effect of dry needling compared with ischemic pressure on trigger point in upper trapezius muscle. Materials and Methods 28 subjects with myofascial trigger point in upper trapezius participated in this study. The subjects were randomly assigned to two groups: dry needling (n = 13 and ischemic pressure (n = 15. The neck lateral flexion range of motion was measured before and after treatment in both groups using a standard goniometer. Paired t-test was used to determine any significant difference in range of motion after treatment sessions compared with pre-treatment score in control and experimental group. Analysis of Covariance (ANCOVA was calculated to determine the significance of differences between the control and experimental groups in post-test scores, with pre-treatment scores used as covariates in the analysis. Results Statistical analysis (paired t-test revealed significant increase in neck lateral flexion range of motion in contra-lateral side after treatment sessions in control and experimental group compared with pre-treatment score (P < 0.05. However, only dry needling was effective in increase of range of motion in Ipsi-lateral side (P = 0.001. In the ANCOVA, controlling for pre-test scores, no significant difference was found between the two groups in the after treatment sessions (P = 0.06 and (P = 0.15. Conclusions The application of DN produces an improvement in ILF and CLF can be prescribed for subjects with MTP in UT muscles.

  18. Increased variability and abnormalities in pancreatic enzyme concentrations in otherwise asymptomatic subjects with type 2 diabetes

    OpenAIRE

    Gurney, Kate; Malloy,; Shan,; Yan,; Chen,

    2012-01-01

    Jaret Malloy, Kate Gurney, Kevin Shan, Ping Yan, Steve ChenAmylin Pharmaceuticals LLC, San Diego, CABackground: Recent studies have demonstrated an increased incidence of pancreatitis in patients with type 2 diabetes compared with obese nondiabetic individuals. Serum lipase and pancreatic amylase concentrations are used in conjunction with clinical findings to diagnose pancreatitis.Methods: In two large clinical trials of overweight/obese nondiabetic and type 2 diabetic subjects, lipase and p...

  19. High-dose inhaled terbutaline increases muscle strength and enhances maximal sprint performance in trained men

    DEFF Research Database (Denmark)

    Hostrup, Morten; Kalsen, Anders; Bangsbo, Jens

    2014-01-01

    PURPOSE: The purpose of the present study was to investigate the effect of high-dose inhaled terbutaline on muscle strength, maximal sprinting, and time-trial performance in trained men. METHODS: Nine non-asthmatic males with a [Formula: see text] of 58.9 ± 3.1 ml min(-1) kg(-1) (mean ± SEM......) participated in a double-blinded randomized crossover study. After administration of inhaled terbutaline (30 × 0.5 mg) or placebo, subjects' maximal voluntary isometric contraction (MVC) of m.quadriceps was measured. After MVC, subjects performed a 30-s Wingate test. Sixty minutes following the Wingate test...... = 0.019) and 3.3 ± 1.0 % (P = 0.009) higher for terbutaline than placebo. Net accumulation of plasma lactate was higher (P = 0.003) for terbutaline than placebo during the Wingate test, whereas [Formula: see text] above baseline was unchanged by terbutaline (P = 0.882). Time-trial performance...

  20. Live high:train low increases muscle buffer capacity and submaximal cycling efficiency.

    Science.gov (United States)

    Gore, C J; Hahn, A G; Aughey, R J; Martin, D T; Ashenden, M J; Clark, S A; Garnham, A P; Roberts, A D; Slater, G J; McKenna, M J

    2001-11-01

    This study investigated whether hypoxic exposure increased muscle buffer capacity (beta(m)) and mechanical efficiency during exercise in male athletes. A control (CON, n=7) and a live high:train low group (LHTL, n=6) trained at near sea level (600 m), with the LHTL group sleeping for 23 nights in simulated moderate altitude (3000 m). Whole body oxygen consumption (VO2) was measured under normoxia before, during and after 23 nights of sleeping in hypoxia, during cycle ergometry comprising 4 x 4-min submaximal stages, 2-min at 5.6 +/- 0.4 W kg(-1), and 2-min 'all-out' to determine total work and VO(2peak). A vastus lateralis muscle biopsy was taken at rest and after a standardized 2-min 5.6 +/- 0.4 W kg(-1) bout, before and after LHTL, and analysed for beta(m) and metabolites. After LHTL, beta(m) was increased (18%, P buffer capacity. Further, reduced VO2 during normoxic exercise after LHTL suggests that improved exercise efficiency is a fundamental adaptation to LHTL.

  1. Diaphragmatic Dysfunction Is Characterized by Increased Duration of Mechanical Ventilation in Subjects With Prolonged Weaning.

    Science.gov (United States)

    Lu, Zhihua; Xu, Qiuping; Yuan, Yuehua; Zhang, Ge; Guo, Feng; Ge, Huiqing

    2016-10-01

    Diaphragmatic dysfunction is often underdiagnosed and is among the risk factors for failed weaning. The purpose of this study was to determine the prevalence of diaphragmatic dysfunction diagnosed by B-mode ultrasonography and to determine whether prolonged weaning subjects with diaphragmatic dysfunction have increased duration of mechanical ventilation compared with those without diaphragmatic dysfunction. This was a prospective observational study in mechanically ventilated subjects who failed ≥3 spontaneous breathing trials or required >7 d of weaning after the first spontaneous breathing trial. Diaphragm thickness was measured in the zone of apposition using a 6-13-MHz ultrasound transducer during a spontaneous breathing trial. The diaphragmatic thickening fraction was calculated as a percentage from the formula: (Thickness at peak inspiration - thickness at end expiration)/thickness at end expiration. Intra-observer and inter-observer reliability were also evaluated. Forty-one subjects (24 males; 62.2 ± 15.9 y old) were included in the study. Of these, the prevalence of ultrasonographic diaphragmatic dysfunction (defined as diaphragmatic thickening fraction of ventilation time after inclusion (293.4 ± 194.8 vs 145.1 ± 101.3 h, P = .02) and ICU stay (29.2 ± 11.4 vs 22.4 ± 7.7 d, P = .03) than subjects without diaphragmatic dysfunction. Diaphragmatic dysfunction as assessed by B-mode ultrasonography is common in subjects with prolonged weaning. Subjects with such diaphragmatic dysfunction show longer mechanical ventilation durations and ICU stays. Copyright © 2016 by Daedalus Enterprises.

  2. Increased neck muscle activity and impaired balance among females with whiplash-related chronic neck pain

    DEFF Research Database (Denmark)

    Juul-Kristensen, Birgit; Clausen, Brian; Ris Hansen, Inge

    2013-01-01

    To investigate neck muscle activity and postural control in patients with whiplash-associated disorder compared with healthy controls.......To investigate neck muscle activity and postural control in patients with whiplash-associated disorder compared with healthy controls....

  3. Increased numbers and functional activity of CD56+ T cells in healthy cytomegalovirus positive subjects

    Science.gov (United States)

    Almehmadi, Mazen; Flanagan, Brian F; Khan, Naeem; Alomar, Suliman; Christmas, Stephen E

    2014-01-01

    Human T cells expressing CD56 are capable of tumour cell lysis following activation with interleukin-2 but their role in viral immunity has been less well studied. Proportions of CD56+ T cells were found to be highly significantly increased in cytomegalovirus-seropositive (CMV+) compared with seronegative (CMV−) healthy subjects (9·1 ± 1·5% versus 3·7 ± 1·0%; P < 0·0001). Proportions of CD56+ T cells expressing CD28, CD62L, CD127, CD161 and CCR7 were significantly lower in CMV+ than CMV− subjects but those expressing CD4, CD8, CD45RO, CD57, CD58, CD94 and NKG2C were significantly increased (P < 0·05), some having the phenotype of T effector memory cells. Levels of pro-inflammatory cytokines and CD107a were significantly higher in CD56+ T cells from CMV+ than CMV− subjects following stimulation with CMV antigens. This also resulted in higher levels of proliferation in CD56+ T cells from CMV+ than CMV− subjects. Using Class I HLA pentamers, it was found that CD56+ T cells from CMV+ subjects contained similar proportions of antigen-specific CD8+ T cells to CD56− T cells in donors of several different HLA types. These differences may reflect the expansion and enhanced functional activity of CMV-specific CD56+ memory T cells. In view of the link between CD56 expression and T-cell cytotoxic function, this strongly implicates CD56+ T cells as being an important component of the cytotoxic T-cell response to CMV in healthy carriers. PMID:24433347

  4. Yoga Poses Increase Subjective Energy and State Self-Esteem in Comparison to 'Power Poses'.

    Science.gov (United States)

    Golec de Zavala, Agnieszka; Lantos, Dorottya; Bowden, Deborah

    2017-01-01

    Research on beneficial consequences of yoga focuses on the effects of yogic breathing and meditation. Less is known about the psychological effects of performing yoga postures. The present study investigated the effects of yoga poses on subjective sense of energy and self-esteem. The effects of yoga postures were compared to the effects of 'power poses,' which arguably increase the sense of power and self-confidence due to their association with interpersonal dominance (Carney et al., 2010). The study tested the novel prediction that yoga poses, which are not associated with interpersonal dominance but increase bodily energy, would increase the subjective feeling of energy and therefore increase self-esteem compared to 'high power' and 'low power' poses. A two factorial, between participants design was employed. Participants performed either two standing yoga poses with open front of the body (n = 19), two standing yoga poses with covered front of the body (n = 22), two expansive, high power poses (n = 21), or two constrictive, low power poses (n = 20) for 1-min each. The results showed that yoga poses in comparison to 'power poses' increased self-esteem. This effect was mediated by an increased subjective sense of energy and was observed when baseline trait self-esteem was controlled for. These results suggest that the effects of performing open, expansive body postures may be driven by processes other than the poses' association with interpersonal power and dominance. This study demonstrates that positive effects of yoga practice can occur after performing yoga poses for only 2 min.

  5. Exercise-induced increase in glucose transport, GLUT-4, and VAMP-2 in plasma membrane from human muscle

    DEFF Research Database (Denmark)

    Kristiansen, S; Hargreaves, Mark; Richter, Erik

    1996-01-01

    contractions may induce trafficking of GLUT-4-containing vesicles via a mechanism similar to neurotransmitter release. Our results demonstrate for the first time exercise-induced translocation of GLUT-4 and VAMP-2 to the plasma membrane of human muscle and increased sarcolemmal glucose transport.......A major effect of muscle contractions is an increase in sarcolemmal glucose transport. We have used a recently developed technique to produce sarcolemmal giant vesicles from human muscle biopsy samples obtained before and after exercise. Six men exercised for 10 min at 50% maximal O2 uptake (Vo2max...

  6. Interrater and intrarater reliability of transverse abdominal and lumbar multifidus muscle thickness in subjects with and without low back pain.

    Science.gov (United States)

    Djordjevic, Olivera; Djordjevic, Aleksandar; Konstantinovic, Ljubica

    2014-12-01

    Two-group, repeated-measures reliability study. To determine interrater and intrarater reliability of ultrasound measurements of transverse abdominal (TrA) and lumbar multifidus (LM) muscle thickness, during rest and contraction, in subjects with low back pain (LBP) and healthy subjects over 3 consecutive days, performed by an experienced and a novice rater. Previous reliability studies of TrA or LM thickness did not simultaneously account for muscle state, rater experience, and multiday assessment in large subject samples. The 2 raters measured TrA and LM thickness on 3 consecutive days in 42 healthy subjects and 56 subjects with LBP, during rest and contraction, and calculated the percent thickness change from rest to contraction. Intraclass correlation coefficients (ICC(2,k)) and 95% minimal detectable change in thickness were derived for a single measure (day 1) and an average measure (days 1-3). The interrater ICC(2,1) values for single-measure thickness (LBP group, 0.71-0.87; healthy group, 0.94-1.00) were similar to those for average-measure thickness (LBP group, 0.73-0.84; healthy group, 0.93-1.00). Both interrater ICC(2,1) and ICC(2,3) were lower for the relative thickness change (0.61-0.96). Intrarater ICC(2,1) values across 3 consecutive days were high for both raters across the 2 groups (LBP group, 0.95-1.00; healthy group, 0.93-1.00), albeit lower for the relative thickness change (0.79-0.99). The 95% minimal detectable changes were < 0.3 mm for the TrA and < 2 mm for the LM (but, in most cases, less than 10% of average thickness). Both experienced and trained novice raters provided reliable measurements of TrA and LM thickness in participants with LBP and healthy participants, during rest and contraction. One-time measurements were similar to averaged measurements. Small absolute errors were observed. Public trial registry: Australian New Zealand Clinical Trials Registry ACTRN12613001077752.

  7. A single bout of exercise increases the expression of glucose but not fatty acid transporters in skeletal muscle of IL-6 KO mice.

    Science.gov (United States)

    Lukaszuk, B; Bialuk, I; Górski, J; Zajączkiewicz, M; Winnicka, M M; Chabowski, A

    2012-08-01

    IL-6 is a biologically active cytokine released during exercise by contracting skeletal muscles. It appears to be highly involved in the regulation of muscles energy substrate utilization. Whether an ablation of IL-6 (IL-6 KO) in mice subjected to a single bout of exercise affects lipid and/or glucose metabolism is currently unknown. In the present study we examined fatty acid (FAT/CD36, FABPpm, FATP-1, FATP-4) as well as glucose (GLUT-1, GLUT-4) transporters expression in IL-6 KO mice. In addition, intramuscular glycogen and lipid content was also evaluated. The expression of all fatty acid transporters (FAT/CD36: +25 %; FATP-1: +31 %; FABPpm: +12.7 %; FATP-4: +7.2 %) was increased in muscles from IL-6 KO mice compared to wild type (WT) mice. Accordingly intramuscular lipid content was also increased in these muscles (FFA: +38 %; DAG: +36 % and TAG: +160 %). Interestingly, IL-6 deficiency had only minor effect on glucose transporters expression (GLUT-1: -4 %, and GLUT-4: -5.1 %), with no apparent difference in muscular glycogen content. A single bout of exercise increased the glucose transporters (GLUT-1: +8 %; GLUT-4: +15 %) as well as FA transporters (FAT/CD36: +13 %; FABPpm: +4.5 %; FATP: +2.5 %, FATP-4: +10 %) expression but only in WT skeletal muscles. In muscles from IL-6 KO mice exercise induced changes only in glucose (GLUT-1: +20 %; GLUT-4: +35 %) but not in the content of FA transporters. Concomitantly, IL-6 KO mice displayed shorter time toward exhaustion with more pronounced reductions in intramuscular lipid and glycogen content. We may speculate, that IL-6 deficiency provokes more pronounced glucose utilization over lipid oxidation during a single bout of exhausting exercise.

  8. Low skeletal muscle mass is associated with increased hospital expenditure in patients undergoing cancer surgery of the alimentary tract.

    Directory of Open Access Journals (Sweden)

    Jeroen L A van Vugt

    Full Text Available Low skeletal muscle mass is associated with poor postoperative outcomes in cancer patients. Furthermore, it is associated with increased healthcare costs in the United States. We investigated its effect on hospital expenditure in a Western-European healthcare system, with universal access.Skeletal muscle mass (assessed on CT and costs were obtained for patients who underwent curative-intent abdominal cancer surgery. Low skeletal muscle mass was defined based on pre-established cut-offs. The relationship between low skeletal muscle mass and hospital costs was assessed using linear regression analysis and Mann-Whitney U-tests.452 patients were included (median age 65, 61.5% males. Patients underwent surgery for colorectal cancer (38.9%, colorectal liver metastases (27.4%, primary liver tumours (23.2%, and pancreatic/periampullary cancer (10.4%. In total, 45.6% had sarcopenia. Median costs were €2,183 higher in patients with low compared with patients with high skeletal muscle mass (€17,144 versus €14,961; P<0.001. Hospital costs incrementally increased with lower sex-specific skeletal muscle mass quartiles (P = 0.029. After adjustment for confounders, low skeletal muscle mass was associated with a cost increase of €4,061 (P = 0.015.Low skeletal muscle mass was independently associated with increased hospital costs of about €4,000 per patient. Strategies to reduce skeletal muscle wasting could reduce hospital costs in an era of incremental healthcare costs and an increasingly ageing population.

  9. Creatine transporter (SLC6A8) knockout mice display an increased capacity for in vitro creatine biosynthesis in skeletal muscle.

    Science.gov (United States)

    Russell, Aaron P; Ghobrial, Lobna; Wright, Craig R; Lamon, Séverine; Brown, Erin L; Kon, Michihiro; Skelton, Matthew R; Snow, Rodney J

    2014-01-01

    The present study aimed to investigate whether skeletal muscle from whole body creatine transporter (CrT; SLC6A8) knockout mice (CrT(-/y)) actually contained creatine (Cr) and if so, whether this Cr could result from an up regulation of muscle Cr biosynthesis. Gastrocnemius muscle from CrT(-/y) and wild type (CrT(+/y)) mice were analyzed for ATP, Cr, Cr phosphate (CrP), and total Cr (TCr) content. Muscle protein and gene expression of the enzymes responsible for Cr biosynthesis L-arginine:glycine amidotransferase (AGAT) and guanidinoacetate methyltransferase (GAMT) were also determined as were the rates of in vitro Cr biosynthesis. CrT(-/y) mice muscle contained measurable (22.3 ± 4.3 mmol.kg(-1) dry mass), but markedly reduced (P < 0.05) TCr levels compared with CrT(+/y) mice (125.0 ± 3.3 mmol.kg(-1) dry mass). AGAT gene and protein expression were higher (~3 fold; P < 0.05) in CrT(-/y) mice muscle, however GAMT gene and protein expression remained unchanged. The in vitro rate of Cr biosynthesis was elevated 1.5 fold (P < 0.05) in CrT(-/y) mice muscle. These data clearly demonstrate that in the absence of CrT protein, skeletal muscle has reduced, but not absent, levels of Cr. This presence of Cr may be at least partly due to an up regulation of muscle Cr biosynthesis as evidenced by an increased AGAT protein expression and in vitro Cr biosynthesis rates in CrT(-/y) mice. Of note, the up regulation of Cr biosynthesis in CrT(-/y) mice muscle was unable to fully restore Cr levels to that found in wild type muscle.

  10. Electrically evoked and voluntary maximal isometric tension in relation to dynamic muscle performance in elderly male subjects, aged 69 years.

    Science.gov (United States)

    Davies, C T; White, M J; Young, K

    1983-01-01

    The dynamic performance and electrically evoked mechanical properties of elderly triceps surae muscle have been investigated in 9 men, aged 69 yr. Dynamic performance consisted of cycling on a force bicycle and a vertical jump off two feet from a force platform. The results showed that the time to peak tension (TPT) and half relaxation time (1/2 RT) were significantly greater (p less than 0.001) by 30 ms and 22 ms and the supramaximal twitch (Pt) and tetanic (20 Hz-P020) tensions and maximal voluntary contraction (MVC) were less by 45 N (-33%), 708 N (-49%), and 899 N (-43%) in the elderly compared with young male control subjects. On the force platform, the height jumped (Ht), maximal force exerted (P), take-off velocity (VT), net impulse (NI) and peak power output (W) were less by 18.6 cm, 173 N, 0.9 ms-1, 52 Ns and 1120 w respectively. Similar differences of power, force and velocity were observed on the force bicycle. The reduction of W in the elderly was associated with the contractile characteristics of the leg muscle. The loss of contractile speed and capacity to to generate force in old people was reflected in their inability to develop power during the performance of a maximal vertical jump and cycling.

  11. High-intensity, unilateral resistance training of a non-paretic muscle group increases active range of motion in a severely paretic upper extremity muscle group after stroke.

    Directory of Open Access Journals (Sweden)

    M. A. Urbin

    2015-05-01

    Full Text Available Limited rehabilitation strategies are available for movement restoration when paresis is too severe following stroke. Previous research has shown that high-intensity resistance training of one muscle group enhances strength of the homologous, contralateral muscle group in neurologically-intact adults. How this cross education phenomenon might be exploited to moderate severe weakness in an upper extremity muscle group after stroke is not well understood. The primary aim of this study was to examine adaptations in force-generating capacity of severely paretic wrist extensors resulting from high-intensity, dynamic contractions of the non-paretic wrist extensors. A secondary, exploratory aim was to probe neural adaptations in a subset of participants from each sample using a single-pulse, transcranial magnetic stimulation protocol. Separate samples of neurologically-intact controls (n=7 and individuals > 4 months post stroke (n=6 underwent 16 sessions of training. Following training, one-repetition maximum of the untrained wrist extensors in the control group and active range of motion of the untrained, paretic wrist extensors in the stroke group were significantly increased. No changes in corticospinal excitability, intracortical inhibition or interhemispheric inhibition were observed in control participants. Both stroke participants who underwent TMS testing, however, exhibited increased voluntary muscle activation following the intervention. In addition, motor-evoked potentials that were unobtainable prior to the intervention were readily elicited afterwards in a stroke participant. Results of this study demonstrate that high-intensity resistance training of a non-paretic upper extremity muscle group can enhance voluntary muscle activation and force-generating capacity of a severely paretic muscle group after stroke. There is also preliminary evidence that corticospinal adaptations may accompany these gains.

  12. Negative mood increases selective attention to food cues and subjective appetite.

    Science.gov (United States)

    Hepworth, Rebecca; Mogg, Karin; Brignell, Catherine; Bradley, Brendan P

    2010-02-01

    Following negative reinforcement and affect-regulation models of dysfunctional appetitive motivation, this study examined the effect of negative mood on objective and subjective cognitive indices of motivation for food; i.e., attentional bias for food cues and self-reported hunger/urge to eat, respectively. The study extended previous research on the effect of mood on food motivation by using (i) an experimental mood manipulation, (ii) an established index of attentional bias from the visual-probe task and (iii) pictorial food cues, which have greater ecological validity than word stimuli. Young female adults (n=80) were randomly allocated to a neutral or negative mood induction procedure. Attentional biases were assessed at two cue exposure durations (500 and 2000ms). Results showed that negative mood increased both attentional bias for food cues and subjective appetite. Attentional bias and subjective appetite were positively inter-correlated, suggesting a common mechanism, i.e. activation of the food-reward system. Attentional bias was also associated with trait eating style, such as external and restrained eating. Thus, current mood and trait eating style each influenced motivation for food (as reflected by subjective appetite and attentional bias). Findings relate to models of cognitive mechanisms underlying normal and dysfunctional appetitive motivation and eating behaviour. 2009 Elsevier Ltd. All rights reserved.

  13. Ultrasound imaging of the diagonal dimension of the deep cervical flexor muscles: A reliability study on healthy subjects.

    Science.gov (United States)

    Ishida, Hiroshi; Suehiro, Tadanobu; Kurozumi, Chiharu; Ono, Koji; Watanabe, Susumu

    2015-07-01

    The purpose of this study is to assess the reliability of a new ultrasound imaging (USI) parameter and procedure for the evaluation of the size of the deep cervical flexor (DCF) muscles. Thirty-one healthy male subjects (21.6 ± 2.5 years old) participated in this study. Two images of the diagonal dimension (DD) of the DCF of the subjects, at 1.5 fingerbreadths below the laryngeal prominence of the thyroid cartilage in a relaxed state, were taken on separate days with a 1-week interval. The intraclass correlation coefficient between the days was 0.82 (95% confidence interval, 0.65-0.91). The standard error of measurement and minimal detectable change were 0.8 mm and 2.1 mm, respectively. The results indicated that the DD may be used as a reliable USI parameter to measure the DCF thickness in healthy subjects. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Single Dose of Intra-Muscular Platlet Rich Plasma Reverses the Increase in Plasma Iron Levels in Exercise Induced Muscle Damage

    Science.gov (United States)

    Pündük, Zekine; Oral, Onur; Özkayın, Nadir; Rahman, Khalid

    2014-01-01

    Objectives: Autologous Platelet Rich Plasma (PRP) therapy, is considered to be a promising solution in accelerating the healing process of injured skeletal muscle tissue. In addition to the release of growth factors, PRP also promotes concentrated anti-inflammatory signals, including interleukins. However, the impact of the intramuscular administration of the PRP on hematologic and biochemical responses has not been fully elucidated in exercise induced muscle damage. Methods: Twelve healthy moderately active male volunteers, without previous experience with eccentric/concentric elbow flexors exercise, participated in this study. They were divided into two groups: control group (CONTROL, n=6) and platelet rich plasma administration group (PRP, n=6) group. To induce muscle damage, subjects in both groups performed concentric/eccentric contractions with load of (80 % 1RM) maximal voluntary contraction of the elbow flexors until point of exhaustion of the non-dominant arm. The non-dominant arms of the PRP group were treated with autologous PRP (Regen ACR-C, Regen Lab, Switzerland) post-24h exercise induced damage (DOMS). Subsequently, 4 ml PRP samples was injected using a 20-gauge needle into the region of the biceps brachii of the non-dominant arm under sterile aseptic conditions. Venous blood samples were collected pre-, and 4 days post-exercise, and analyzed for complete blood counts, serum ferritin, iron, iron binding capacity (IBC), creatinine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), alanine aminotransferase (ALT) as markers of muscle damage and inflammation. Results: We found that the baseline levels of iron, ferritin, IBC, CK, LDH, AST and ALT were similar in control and PRP groups. However, 24 h following exercise induced muscle damage a significant increase in these parameters was observed in both groups. Interestingly, PRP administration decreased plasma iron levels compared to the control group but this was only achieved on

  15. Failure of activation of spinal motoneurones after muscle fatigue in healthy subjects studied by transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Andersen, Birgit; Westlund, Barbro; Krarup, Christian

    2003-01-01

    During a sustained maximal effort a progressive decline in the ability to drive motoneurones (MNs) develops. We used the recently developed triple stimulation technique (TST) to study corticospinal conduction after fatiguing exercise in healthy subjects. This method employs a collision technique...... to control levels within 1 min and implies that a decreased number of spinal MNs were excited. Additional TST experiments after maximal and submaximal efforts showed that the decrease in size of the TST response was related to duration and strength of exercise. Motor evoked potentials (MEPs) after...... response depression. Overall, the results suggest that the outflow from the motor cortex could become insufficient to drive all spinal MNs to discharge when the muscle is fatigued and that complex interactions between failure of activation and compensatory mechanisms to maintain motor unit activation occur...

  16. Expression of the major insulin regulatable glucose transporter (GLUT4) in skeletal muscle of noninsulin-dependent diabetic patients and healthy subjects before and after insulin infusion

    DEFF Research Database (Denmark)

    Andersen, P H; Lund, S; Vestergaard, H

    1993-01-01

    In a cross-sectional study we have examined the regulatory effect of insulin in vivo on the major insulin regulatable glucose transporter (GLUT4) in vastus lateralis muscle from 12 noninsulin-dependent diabetes mellitus (NIDDM) patients and 8 healthy control subjects. Insulin-stimulated glucose...... in the NIDDM patients. The GLUT4 protein per DNA of muscle obtained in the basal state correlated positively with the in vivo insulin-stimulated glucose uptake rate in the control group (r = 0.82, P ... protein content in skeletal muscle after 4 h of insulin infusion did not correlate with insulin-stimulated glucose uptake in any of the groups. In conclusion, 4 h of insulin infusion causing supraphysiological serum insulin levels modulates the expression of GLUT4 in skeletal muscle from healthy subjects...

  17. Muscle Deoxygenation Causes Muscle Fatigue

    Science.gov (United States)

    Murthy, G.; Hargens, A. R.; Lehman, S.; Rempel, D.

    1999-01-01

    Muscle fatigue is a common musculoskeletal disorder in the work place, and may be a harbinger for more disabling cumulative trauma disorders. Although the cause of fatigue is multifactorial, reduced blood flow and muscle oxygenation may be the primary factor in causing muscle fatigue during low intensity muscle exertion. Muscle fatigue is defined as a reduction in muscle force production, and also occurs among astronauts who are subjected to postural constraints while performing lengthy, repetitive tasks. The objectives of this research are to: 1) develop an objective tool to study the role of decreased muscle oxygenation on muscle force production, and 2) to evaluate muscle fatigue during prolonged glovebox work.

  18. A mutation in the myostatin gene increases muscle mass and enhances racing performance in heterozygote dogs.

    Directory of Open Access Journals (Sweden)

    Dana S Mosher

    2007-05-01

    Full Text Available Double muscling is a trait previously described in several mammalian species including cattle and sheep and is caused by mutations in the myostatin (MSTN gene (previously referred to as GDF8. Here we describe a new mutation in MSTN found in the whippet dog breed that results in a double-muscled phenotype known as the "bully" whippet. Individuals with this phenotype carry two copies of a two-base-pair deletion in the third exon of MSTN leading to a premature stop codon at amino acid 313. Individuals carrying only one copy of the mutation are, on average, more muscular than wild-type individuals (p = 7.43 x 10(-6; Kruskal-Wallis Test and are significantly faster than individuals carrying the wild-type genotype in competitive racing events (Kendall's nonparametric measure, tau = 0.3619; p approximately 0.00028. These results highlight the utility of performance-enhancing polymorphisms, marking the first time a mutation in MSTN has been quantitatively linked to increased athletic performance.

  19. New evidence of increased risk of rhinitis in subjects with COPD: a longitudinal population study

    Directory of Open Access Journals (Sweden)

    Bergqvist J

    2016-10-01

    Full Text Available Joel Bergqvist,1 Anders Andersson,2 Anna-Carin Olin,3 Nicola Murgia,3,4 Linus Schiöler,3 Mogens Bove,5 Johan Hellgren1 1Department of Otorhinolaryngology, Head and Neck Surgery, Institute of Clinical Sciences, 2Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, 3Department of Occupational and Environmental Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; 4Department of Medicine, Section of Occupational Medicine, Respiratory Diseases and Toxicology, University of Perugia, Perugia, Italy; 5Department of ENT and Oral Maxillofacial Surgery, NU Hospital Group, Trollhättan, Sweden Background: The aim of this population-based study was to investigate the risk of developing noninfectious rhinitis (NIR in subjects with chronic obstructive pulmonary disease (COPD. Materials and methods: This is a longitudinal population-based study comprising 3,612 randomly selected subjects from Gothenburg, Sweden, aged 25–75 years. Lung function was measured at baseline with spirometry and the included subjects answered a questionnaire on respiratory symptoms. At follow-up, the subjects answered a questionnaire with a response rate of 87%. NIR was defined as symptoms of nasal obstruction, nasal secretion, and/or sneezing attacks without having a cold, during the last 5 years. COPD was defined as a spirometry ratio of forced expiratory volume in 1 second divided by forced vital capacity (FEV1/FVC <0.7. Subjects who reported asthma and NIR at baseline were excluded from the study. The odds ratios for developing NIR (ie, new-onset NIR in relation to age, gender, body mass index, COPD, smoking, and atopy were calculated. Results: In subjects with COPD, the 5-year incidence of NIR was significantly increased (10.8% vs 7.4%, P=0.005 and was higher among subjects aged >40 years. Smoking, atopy, and occupational exposure to gas, fumes, or dust were also associated with new-onset NIR. COPD, smoking, and atopy remained

  20. Effect of increased fruit and vegetable consumption on physical function and muscle strength in older adults.

    Science.gov (United States)

    Neville, Charlotte E; Young, Ian S; Gilchrist, Sarah E C M; McKinley, Michelle C; Gibson, Andrew; Edgar, J David; Woodside, Jayne V

    2013-12-01

    Fruit and vegetable (FV) intake, which is often low in older people, may be associated with improved muscle strength and physical function. However, there is a shortage of intervention trial evidence to support this. The current study examined the effect of increased FV consumption on measures of muscle strength and physical function among healthy, free-living older adults. A randomized controlled intervention study was undertaken. Eighty-three participants aged 65-85 years, habitually consuming ≤ 2 portions of FV/day, were randomised to continue their normal diet (≤ 2 portions/day), or to consume ≥ 5 portions of FV/day for 16 weeks. FV were delivered to all participants each week, free of charge. Compliance was monitored at baseline, 6, 12 and 16 weeks by diet history and by measuring biomarkers of micronutrient status. Grip strength was measured by a hand-held dynamometer, while lower-extremity physical function was assessed by performance-based measures. Eighty-two participants completed the intervention. The 5 portions/day group showed greater change in daily FV consumption compared to the 2 portions/day group (P function between the two groups. However, there was a trend towards a greater change in grip strength in the 5 portions/day compared to the 2 portions/day group (mean change at 16 weeks ± SD, 2.04 ± 5.16 and 0.11 ± 3.26 kg, respectively, P = 0.06). Increased FV consumption may modestly increase grip strength but has no effect on physical function in healthy older adults.

  1. Lower extremity muscle activation onset times during the transition from double-leg stance to single-leg stance in anterior cruciate ligament reconstructed subjects.

    Science.gov (United States)

    Dingenen, Bart; Janssens, Luc; Claes, Steven; Bellemans, Johan; Staes, Filip F

    2016-06-01

    Previous studies mainly focused on muscles at the operated knee after anterior cruciate ligament reconstruction, less on muscles around other joints of the operated and non-operated leg. The aim of this study was to investigate muscle activation onset times during the transition from double-leg stance to single-leg stance in anterior cruciate ligament reconstructed subjects. Lower extremity muscle activation onset times of both legs of 20 fully returned to sport anterior cruciate ligament reconstructed subjects and 20 non-injured control subjects were measured during the transition from double-leg stance to single-leg stance in eyes open and eyes closed conditions. Analysis of covariance (ANCOVA) was used to evaluate differences between groups and differences between legs within both groups, while controlling for peak center of pressure velocity. Significantly delayed muscle activation onset times were found in the anterior cruciate ligament reconstructed group compared to the control group for gluteus maximus, gluteus medius, vastus medialis obliquus, medial hamstrings, lateral hamstrings and gastrocnemius in both eyes open and eyes closed conditions (Panterior cruciate ligament reconstructed group, no significant different muscle activation onset times were found between the operated and non-operated leg (P>.05). Despite completion of rehabilitation and full return to sport, the anterior cruciate ligament reconstructed group showed neuromuscular control deficits that were not limited to the operated knee joint. Clinicians should focus on relearning multi-segmental anticipatory neuromuscular control strategies after anterior cruciate ligament reconstruction. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Strength training to contraction failure increases voluntary activation of the quadriceps muscle shortly after total knee arthroplasty

    DEFF Research Database (Denmark)

    Mikkelsen, Elin Karin; Jakobsen, Thomas Linding; Holsgaard-Larsen, Anders

    2016-01-01

    arthroplasty. One set of knee extensions was performed until contraction failure, using a predetermined 10 repetition maximum loading. In the operated leg, electromyographic (EMG) activity of the lateral and medial vastus, semitendinosus, and biceps femoris muscles was recorded during the set. Muscle activity...... failure (P = 0.0006 and 0.0187). CONCLUSION: In patients shortly after total knee arthroplasty, 10 repetition maximum-loaded knee extensions performed in one set until contraction failure increases voluntary activation of the quadriceps muscle during the set. CLINICAL TRIALS: Gov-identifier: NCT01713140...

  3. Acute ozone exposure increases plasma prostaglandin F2 alpha in ozone-sensitive human subjects

    Energy Technology Data Exchange (ETDEWEB)

    Schelegle, E.S.; Adams, W.C.; Giri, S.N.; Siefkin, A.D.

    1989-07-01

    Twenty O/sub 3/-sensitive and /sup 2/O O/sub 3/-nonsensitive subjects participated in a study to investigate the effects of disparate O/sub 3/ sensitivity on plasma prostaglandin F2 alpha responses consequent to exposure to ambient O3 concentrations. Subjects were selected from a pool of 75 normal healthy college-aged males who had been previously exposed to 0.35 ppm O3 for 1 h at an exercising VE of 60 L/min. The selection criterion used was the observed decrement in FEV1 after the O/sub 3/ exposure: O/sub 3/-sensitive, FEV1 decrement greater than 24%; O/sub 3/-nonsensitive, FEV1 decrement less than 11%. Each subject was exposed to filtered air and to 0.20 and 0.35 ppm O/sub 3/ for 80 min while exercising at a VE of 50 L/min. These experimental protocols were divided into two 40-min sessions separated by a period of 4 to 10 min. PGF2 alpha, FVC, FEV1, and FEF25-75 were evaluated before, during, and after each protocol. SGaw and Vtg were measured before and after each protocol. Plasma PGF2 alpha was significantly increased in the O/sub 3/-sensitive group during and after the 0.35-ppm O/sub 3/ exposure.

  4. Increased CaVβ1a Expression with Aging Contributes to Skeletal Muscle Weakness

    Science.gov (United States)

    Taylor, Jackson R.; Zheng, Zhenlin; Wang, Zhong-Min; Payne, Anthony M.; Messi, María L.; Delbono, Osvaldo

    2009-01-01

    Summary Ca2+ release from the sarcoplasmic reticulum (SR) into the cytosol is a crucial part of excitation-contraction (E-C) coupling. E-C uncoupling, a deficit in Ca2+ release from the SR, is thought to be responsible for at least some of the loss in specific force observed in aging skeletal muscle. E-C uncoupling may be caused by alterations in expression of the voltage-dependent calcium channel α1s (CaV1.1) and β1a (CaVβ1a) subunits, both of which are necessary for E-C coupling to occur. While previous studies have found CaV1.1 expression declines in old rodents, CaVβ1a expression has not been previously examined in aging models. Western blot analysis shows a substantial increase of CaVβ1a expression over the full lifespan of FVB mice. To examine the specific effects of CaVβ1a overexpression, a CaVβ1a -YFP plasmid was electroporated in vivo into young animals. The resulting increase in expression of CaVβ1a corresponded to decline of CaV1.1 over the same time period. YFP fluorescence, used as a measure of CaVβ1a -YFP expression in individual fibers, also showed an inverse relationship with charge movement, measured using the whole-cell patch-clamp technique. Specific force was significantly reduced in young CaVβ1a - YFP electroporated muscle fibers compared to sham-electroporated, age-matched controls. siRNA interference of CaVβ1a in young muscles reduced charge movement, while charge movement in old was restored to young control levels. These studies imply CaVβ1a serves as both a positive and negative regulator CaV1.1 expression, and that endogenous overexpression of CaVβ1a during old age may play a role in the loss of specific force. PMID:19663902

  5. Increased CaVbeta1A expression with aging contributes to skeletal muscle weakness.

    Science.gov (United States)

    Taylor, Jackson R; Zheng, Zhenlin; Wang, Zhong-Min; Payne, Anthony M; Messi, María L; Delbono, Osvaldo

    2009-09-01

    Ca2+ release from the sarcoplasmic reticulum (SR) into the cytosol is a crucial part of excitation-contraction (E-C) coupling. Excitation-contraction uncoupling, a deficit in Ca2+ release from the SR, is thought to be responsible for at least some of the loss in specific force observed in aging skeletal muscle. Excitation-contraction uncoupling may be caused by alterations in expression of the voltage-dependent calcium channel alpha1s (CaV1.1) and beta1a (CaVbeta1a) subunits, both of which are necessary for E-C coupling to occur. While previous studies have found CaV1.1 expression declines in old rodents, CaVbeta1a expression has not been previously examined in aging models. Western blot analysis shows a substantial increase of CaVbeta1a expression over the full lifespan of Friend Virus B (FVB) mice. To examine the specific effects of CaVbeta1a overexpression, a CaVbeta1a-YFP plasmid was electroporated in vivo into young animals. The resulting increase in expression of CaVbeta1a corresponded to decline of CaV1.1 over the same time period. YFP fluorescence, used as a measure of CaVbeta1a-YFP expression in individual fibers, also showed an inverse relationship with charge movement, measured using the whole-cell patch-clamp technique. Specific force was significantly reduced in young CaVbeta1a-YFP electroporated muscle fibers compared with sham-electroporated, age-matched controls. siRNA interference of CaVbeta1a in young muscles reduced charge movement, while charge movement in old was restored to young control levels. These studies imply CaVbeta1a serves as both a positive and negative regulator CaV1.1 expression, and that endogenous overexpression of CaVbeta1a during old age may play a role in the loss of specific force.

  6. Sociocultural influences on strategies to lose weight, gain weight, and increase muscles among ten cultural groups.

    Science.gov (United States)

    McCabe, Marita P; Busija, Lucy; Fuller-Tyszkiewicz, Matthew; Ricciardelli, Lina; Mellor, David; Mussap, Alexander

    2015-01-01

    This study determined how sociocultural messages to change one's body are perceived by adolescents from different cultural groups. In total, 4904 adolescents, including Australian, Chilean, Chinese, Indo-Fijian, Indigenous Fijian, Greek, Malaysian, Chinese Malaysian, Tongans in New Zealand, and Tongans in Tonga, were surveyed about messages from family, peers, and the media to lose weight, gain weight, and increase muscles. Groups were best differentiated by family pressure to gain weight. Girls were more likely to receive the messages from multiple sociocultural sources whereas boys were more likely to receive the messages from the family. Some participants in a cultural group indicated higher, and others lower, levels of these sociocultural messages. These findings highlight the differences in sociocultural messages across cultural groups, but also that adolescents receive contrasting messages within a cultural group. These results demonstrate the difficulty in representing a particular message as being characteristic of each cultural group. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Increased variability and abnormalities in pancreatic enzyme concentrations in otherwise asymptomatic subjects with type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Malloy J

    2012-12-01

    Full Text Available Jaret Malloy, Kate Gurney, Kevin Shan, Ping Yan, Steve ChenAmylin Pharmaceuticals LLC, San Diego, CABackground: Recent studies have demonstrated an increased incidence of pancreatitis in patients with type 2 diabetes compared with obese nondiabetic individuals. Serum lipase and pancreatic amylase concentrations are used in conjunction with clinical findings to diagnose pancreatitis.Methods: In two large clinical trials of overweight/obese nondiabetic and type 2 diabetic subjects, lipase and pancreatic amylase were measured at screening and 2–5 weeks later at baseline (prior to treatment with study medication.Results: Lipase and pancreatic amylase concentrations were above the upper limit of normal (ULN in 13% and 6% of type 2 diabetic subjects, respectively, and were approximately three-fold (3 × higher than the proportion of nondiabetic subjects with levels above ULN. Elevations exceeding ULN were seen in many subjects asymptomatic for pancreatitis; however, elevations >2 × ULN and >3 × ULN were uncommon, and elevations >3 × ULN were often associated with a history of dyslipidemia, hyperlipidemia, and gastrointestinal disorders. Additionally, enzyme concentrations varied within this 2–5-week screening period, including shifts between elevated and normal levels.Conclusion: Results from this post hoc analysis suggest that, although pancreatic enzymes can be a useful marker for pancreatitis within the proper clinical context, diagnosis of pancreatitis may be confounded in populations known to have asymptomatic elevations associated with disease, such as type 2 diabetes. Further effort is needed to clarify the etiology and epidemiology of pancreatic enzyme elevations in type 2 diabetes.Keywords: diabetes, pancreatitis, amylase, lipase

  8. Intense resistance exercise induces early and transient increases in ryanodine receptor 1 phosphorylation in human skeletal muscle.

    Directory of Open Access Journals (Sweden)

    Sebastian Gehlert

    Full Text Available BACKGROUND: While ryanodine receptor 1 (RyR1 critically contributes to skeletal muscle contraction abilities by mediating Ca²⁺ion oscillation between sarcoplasmatic and myofibrillar compartments, AMP-activated protein kinase (AMPK senses contraction-induced energetic stress by phosphorylation at Thr¹⁷². Phosphorylation of RyR1 at serine²⁸⁴³ (pRyR1Ser²⁸⁴³ results in leaky RyR1 channels and impaired Ca²⁺homeostasis. Because acute resistance exercise exerts decreased contraction performance in skeletal muscle, preceded by high rates of Ca²⁺-oscillation and energetic stress, intense myofiber contractions may induce increased RyR1 and AMPK phosphorylation. However, no data are available regarding the time-course and magnitude of early RyR1 and AMPK phosphorylation in human myofibers in response to acute resistance exercise. PURPOSE: Determine the effects and early time-course of resistance exercise on pRyR1Ser²⁸⁴³ and pAMPKThr¹⁷² in type I and II myofibers. METHODS: 7 male subjects (age 23±2 years, height: 185±7 cm, weight: 82±5 kg performed 3 sets of 8 repetitions of maximum eccentric knee extensions. Muscle biopsies were taken at rest, 15, 30 and 60 min post exercise. pRyR1Ser²⁸⁴³ and pAMPKThr¹⁷² levels were determined by western blot and semi-quantitative immunohistochemistry techniques. RESULTS: While total RyR1 and total AMPK levels remained unchanged, RyR1 was significantly more abundant in type II than type I myofibers. pRyR1Ser²⁸⁴³ increased 15 min and peaked 30 min (p<0.01 post exercise in both myofiber types. Type I fibers showed relatively higher increases in pRyR1Ser²⁸⁴³ levels than type II myofibers and remained elevated up to 60 min post resistance exercise (p<0.05. pAMPKThr¹⁷² also increased 15 to 30 min post exercise (p<0.01 in type I and II myofibers and in whole skeletal muscle. CONCLUSION: Resistance exercise induces acutely increased pRyR1Ser²⁸⁴³ and

  9. Reduced efficiency, but increased fat oxidation, in mitochondria from human skeletal muscle after 24-h ultraendurance exercise

    DEFF Research Database (Denmark)

    Fernström, Maria; Bakkman, Linda; Tonkonogi, Michail

    2007-01-01

    The hypothesis that ultraendurance exercise influences muscle mitochondrial function has been investigated. Athletes in ultraendurance performance performed running, kayaking, and cycling at 60% of their peak O(2) consumption for 24 h. Muscle biopsies were taken preexercise (Pre-Ex), postexercise...... exercise (+13%). The increased mitochondrial capacity for PC oxidation indicates plasticity in substrate oxidation at the mitochondrial level, which may be of advantage during prolonged exercise....

  10. Immobilization and therapeutic passive stretching generate thickening and increase the expression of laminin and dystrophin in skeletal muscle

    Energy Technology Data Exchange (ETDEWEB)

    Cação-Benedini, L.O.; Ribeiro, P.G. [Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Medicina e Reabilitação do Aparelho Locomotor, Departamento de Biomecânica, Ribeirão Preto, SP, Brasil, Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Prado, C.M.; Chesca, D.L. [Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Departamento de Patologia, Ribeirão Preto, SP, Brasil, Departamento de Patologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Mattiello-Sverzut, A.C. [Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Medicina e Reabilitação do Aparelho Locomotor, Departamento de Biomecânica, Ribeirão Preto, SP, Brasil, Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)

    2014-05-09

    Extracellular matrix and costamere proteins transmit the concentric, isometric, and eccentric forces produced by active muscle contraction. The expression of these proteins after application of passive tension stimuli to muscle remains unknown. This study investigated the expression of laminin and dystrophin in the soleus muscle of rats immobilized with the right ankle in plantar flexion for 10 days and subsequent remobilization, either by isolated free movement in a cage or associated with passive stretching for up to 10 days. The intensity of the macrophage response was also evaluated. One hundred and twenty-eight female Wistar rats were divided into 8 groups: free for 10 days; immobilized for 10 days; immobilized/free for 1, 3, or 10 days; or immobilized/stretched/free for 1, 3, or 10 days. After the experimental procedures, muscle tissue was processed for immunofluorescence (dystrophin/laminin/CD68) and Western blot analysis (dystrophin/laminin). Immobilization increased the expression of dystrophin and laminin but did not alter the number of macrophages in the muscle. In the stretched muscle groups, there was an increase in dystrophin and the number of macrophages after 3 days compared with the other groups; dystrophin showed a discontinuous labeling pattern, and laminin was found in the intracellular space. The amount of laminin was increased in the muscles treated by immobilization followed by free movement for 10 days. In the initial stages of postimmobilization (1 and 3 days), an exacerbated macrophage response and an increase of dystrophin suggested that the therapeutic stretching technique induced additional stress in the muscle fibers and costameres.

  11. Cyclic strain increases protease-activated receptor-1 expression in vascular smooth muscle cells

    Science.gov (United States)

    Nguyen, K. T.; Frye, S. R.; Eskin, S. G.; Patterson, C.; Runge, M. S.; McIntire, L. V.

    2001-01-01

    Cyclic strain regulates many vascular smooth muscle cell (VSMC) functions through changing gene expression. This study investigated the effects of cyclic strain on protease-activated receptor-1 (PAR-1) expression in VSMCs and the possible signaling pathways involved, on the basis of the hypothesis that cyclic strain would enhance PAR-1 expression, reflecting increased thrombin activity. Uniaxial cyclic strain (1 Hz, 20%) of cells cultured on elastic membranes induced a 2-fold increase in both PAR-1 mRNA and protein levels. Functional activity of PAR-1, as assessed by cell proliferation in response to thrombin, was also increased by cyclic strain. In addition, treatment of cells with antioxidants or an NADPH oxidase inhibitor blocked strain-induced PAR-1 expression. Preincubation of cells with protein kinase inhibitors (staurosporine or Ro 31-8220) enhanced strain-increased PAR-1 expression, whereas inhibitors of NO synthase, tyrosine kinase, and mitogen-activated protein kinases had no effect. Cyclic strain in the presence of basic fibroblast growth factor induced PAR-1 mRNA levels beyond the effect of cyclic strain alone, whereas no additive effect was observed between cyclic strain and platelet-derived growth factor-AB. Our findings that cyclic strain upregulates PAR-1 mRNA expression but that shear stress downregulates this gene in VSMCs provide an opportunity to elucidate signaling differences by which VSMCs respond to different mechanical forces.

  12. Dietary L-arginine supplementation increases muscle gain and reduces body fat mass in growing-finishing pigs.

    Science.gov (United States)

    Tan, Bie; Yin, Yulong; Liu, Zhiqiang; Li, Xinguo; Xu, Haijun; Kong, Xiangfeng; Huang, Ruilin; Tang, Wenjie; Shinzato, Izuru; Smith, Stephen B; Wu, Guoyao

    2009-05-01

    Obesity in humans is a major public health crisis worldwide. In addition, livestock species exhibit excessive subcutaneous fat at market weight. However, there are currently few means of reducing adiposity in mammals. This study was conducted with a swine model to test the hypothesis that dietary L-arginine supplementation may increase muscle gain and decrease fat deposition. Twenty-four 110-day-old barrows were assigned randomly into two treatments, representing supplementation with 1.0% L-arginine or 2.05% L-alanine (isonitrogenous control) to a corn- and soybean meal-based diet. Growth performance was measured based on weight gain and food intake. After a 60-day period of supplementation, carcass and muscle composition were measured. Serum triglyceride concentration was 20% lower (P gain by 6.5% and carcass skeletal-muscle content by 5.5%, while decreasing (P muscle protein, glycogen, and fat contents by 4.8, 42, and 70%, respectively, as well as muscle pH at 45 min post-mortem by 0.32, while reducing muscle lactate content by 37%. These results support our hypothesis that dietary arginine supplementation beneficially promotes muscle gain and reduces body fat accretion in growing-finishing pigs. The findings have a positive impact on development of novel therapeutics to treat human obesity and enhance swine lean-tissue growth.

  13. Diquafosol Tetrasodium Increases the Concentration of Mucin-like Substances in Tears of Healthy Human Subjects.

    Science.gov (United States)

    Shigeyasu, Chika; Hirano, Shinichiro; Akune, Yoko; Yamada, Masakazu

    2015-09-01

    This study was undertaken to determine the effect of topical application of diquafosol tetrasodium on proteins and mucin-like substances from tears of clinically healthy subjects. Tears were collected from both the eyes of 10 healthy volunteers. Diquafosol tetrasodium solution (3%) was applied once to the right eye and 0.9% sodium chloride solution (saline) once to the left eye. Tear samples were collected by Schirmer test strips before application and 5, 15, 30 and 60 min after application. Sialic acid, a marker of mucin-like substances, and major tear proteins including secretory IgA, lactoferrin, lipocalin-1, and lysozyme were measured by high performance liquid chromatography. Levels of total protein, sIgA and lysozyme were transiently decreased in both groups but returned to baseline levels within 15 min after application. The concentration of lactoferrin and lipocalin-1 did not change significantly in both groups. Sialic acid in tears was significantly decreased 5 min after saline application, but significantly increased 5 min after diquafosol application. No significant difference in sialic acid was seen after 15 min in both groups. Topical application of saline and diquafosol resulted in transient decrease of tear proteins possibly due to wash out or dilution effects. In contrast, diquafosol application significantly increased sialic acid, although the effect was transient. This suggests diquafosol stimulates the secretion of mucins from ocular tissues of healthy human subjects.

  14. Stochastic resonance whole body vibration increases perceived muscle relaxation but not cardiovascular activation: A randomized controlled trial.

    Science.gov (United States)

    Elfering, Achim; Burger, Christian; Schade, Volker; Radlinger, Lorenz

    2016-11-18

    To investigate the acute effects of stochastic resonance whole body vibration (SR-WBV), including muscle relaxation and cardiovascular activation. Sixty-four healthy students participated. The participants were randomly assigned to sham SR-WBV training at a low intensity (1.5 Hz) or a verum SR-WBV training at a higher intensity (5 Hz). Systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR) and self-reported muscle relaxation were assessed before and immediately after SR-WBV. Two factorial analyses of variance (ANOVA) showed a significant interaction between pre- vs post-SR-WBV measurements and SR-WBV conditions for muscle relaxation in the neck and back [F(1,55) = 3.35, P = 0.048, η2 = 0.07]. Muscle relaxation in the neck and back increased in verum SR-WBV, but not in sham SR-WBV. No significant changes between pre- and post-training levels of SBD, DBD and HR were observed either in sham or verum SR-WBV conditions. With verum SR-WBV, improved muscle relaxation was the most significant in participants who reported the experience of back, neck or shoulder pain more than once a month (P < 0.05). A single session of SR-WBV increased muscle relaxation in young healthy individuals, while cardiovascular load was low. An increase in musculoskeletal relaxation in the neck and back is a potential mediator of pain reduction in preventive worksite SR-WBV trials.

  15. Increased serum inflammatory markers in the absence of clinical and skeletal muscle inflammation in patients with chronic obstructive pulmonary disease.

    Science.gov (United States)

    Piehl-Aulin, Karin; Jones, Ian; Lindvall, Björn; Magnuson, Anders; Abdel-Halim, Samy M

    2009-01-01

    Muscle wasting and cachexia are common occurrences in patients with chronic obstructive pulmonary disease (COPD). The current study aimed to investigate markers of inflammation in the circulation and skeletal muscle that might be associated with development of muscle wasting. Three groups of patients with mild, moderate and severe COPD and matched healthy controls were recruited. Serum levels of C-reactive protein (CRP), high-sensitivity CRP (hs-CRP), IL-6, IL-8, TNF-alpha, cortisol, insulin-like growth factor 1 (IGF-1), leptin and ghrelin were analysed. Skeletal muscle inflammation was investigated microscopically using a panel of antibodies and standard staining for inflammatory cell infiltration. All COPD patients were clinically stable, with no sign of inflammation and normal CRP values. Compared to controls, significantly increased hs-CRP levels were observed in all COPD patient groups. Significant rises in IL-6 levels were first observed in moderate COPD, while IL-8 levels were significantly elevated at the late severe stage. Circulating levels of TNF-alpha, cortisol, IGF-1, leptin and ghrelin were similar to control levels. No microscopic signs of skeletal muscle inflammation were observed. Our results identify hs-CRP as an early marker of inflammation that is significantly increased in the circulation even in mild COPD. Serum interleukin levels appear to be increased with disease progress. These changes were manifested in the absence of any clinical signs of disease exacerbation, evidence of skeletal muscle inflammation or hormonal changes.

  16. Chronic hypobaric hypoxia increases isolated rat fast-twitch and slow-twitch limb muscle force and fatigue.

    Science.gov (United States)

    El-Khoury, R; Bradford, A; O'Halloran, K D

    2012-01-01

    Chronic hypoxia alters respiratory muscle force and fatigue, effects that could be attributed to hypoxia and/or increased activation due to hyperventilation. We hypothesized that chronic hypoxia is associated with phenotypic change in non-respiratory muscles and therefore we tested the hypothesis that chronic hypobaric hypoxia increases limb muscle force and fatigue. Adult male Wistar rats were exposed to normoxia or hypobaric hypoxia (PB=450 mm Hg) for 6 weeks. At the end of the treatment period, soleus (SOL) and extensor digitorum longus (EDL) muscles were removed under pentobarbitone anaesthesia and strips were mounted for isometric force determination in Krebs solution in standard water-jacketed organ baths at 25 °C. Isometric twitch and tetanic force, contractile kinetics, force-frequency relationship and fatigue characteristics were determined in response to electrical field stimulation. Chronic hypoxia increased specific force in SOL and EDL compared to age-matched normoxic controls. Furthermore, chronic hypoxia decreased endurance in both limb muscles. We conclude that hypoxia elicits functional plasticity in limb muscles perhaps due to oxidative stress. Our results may have implications for respiratory disorders that are characterized by prolonged hypoxia such as chronic obstructive pulmonary disease (COPD).

  17. Regulation of Increased Blood Flow (Hyperemia) to Muscles During Exercise: A Hierarchy of Competing Physiological Needs

    Science.gov (United States)

    Joyner, Michael J.; Casey, Darren P.

    2015-01-01

    This review focuses on how blood flow to contracting skeletal muscles is regulated during exercise in humans. The idea is that blood flow to the contracting muscles links oxygen in the atmosphere with the contracting muscles where it is consumed. In this context, we take a top down approach and review the basics of oxygen consumption at rest and during exercise in humans, how these values change with training, and the systemic hemodynamic adaptations that support them. We highlight the very high muscle blood flow responses to exercise discovered in the 1980s. We also discuss the vasodilating factors in the contracting muscles responsible for these very high flows. Finally, the competition between demand for blood flow by contracting muscles and maximum systemic cardiac output is discussed as a potential challenge to blood pressure regulation during heavy large muscle mass or whole body exercise in humans. At this time, no one dominant dilator mechanism accounts for exercise hyperemia. Additionally, complex interactions between the sympathetic nervous system and the microcirculation facilitate high levels of systemic oxygen extraction and permit just enough sympathetic control of blood flow to contracting muscles to regulate blood pressure during large muscle mass exercise in humans. PMID:25834232

  18. Regulation of increased blood flow (hyperemia) to muscles during exercise: a hierarchy of competing physiological needs.

    Science.gov (United States)

    Joyner, Michael J; Casey, Darren P

    2015-04-01

    This review focuses on how blood flow to contracting skeletal muscles is regulated during exercise in humans. The idea is that blood flow to the contracting muscles links oxygen in the atmosphere with the contracting muscles where it is consumed. In this context, we take a top down approach and review the basics of oxygen consumption at rest and during exercise in humans, how these values change with training, and the systemic hemodynamic adaptations that support them. We highlight the very high muscle blood flow responses to exercise discovered in the 1980s. We also discuss the vasodilating factors in the contracting muscles responsible for these very high flows. Finally, the competition between demand for blood flow by contracting muscles and maximum systemic cardiac output is discussed as a potential challenge to blood pressure regulation during heavy large muscle mass or whole body exercise in humans. At this time, no one dominant dilator mechanism accounts for exercise hyperemia. Additionally, complex interactions between the sympathetic nervous system and the microcirculation facilitate high levels of systemic oxygen extraction and permit just enough sympathetic control of blood flow to contracting muscles to regulate blood pressure during large muscle mass exercise in humans. Copyright © 2015 the American Physiological Society.

  19. Alterations of systemic and muscle iron metabolism in human subjects treated with low-dose recombinant erythropoietin

    DEFF Research Database (Denmark)

    Robach, Paul; Recalcati, Stefania; Girelli, Domenico

    2009-01-01

    no appreciable change in myoglobin levels was observed, which suggests unaltered muscle oxygen homeostasis. In conclusion, under rhEpo stimulation, the changes in the expression of muscle iron proteins indicate the occurrence of skeletal muscle iron accumulation despite the remarkable hepcidin suppression...

  20. Dexamethasone increases glucose cycling, but not glucose production, in healthy subjects

    Energy Technology Data Exchange (ETDEWEB)

    Wajngot, A.; Khan, A.; Giacca, A.; Vranic, M.; Efendic, S. (Karolinska Hospital, Stockholm (Sweden))

    1990-11-01

    We established that measurement of glucose fluxes through glucose-6-phosphatase (G-6-Pase; hepatic total glucose output, HTGO), glucose cycling (GC), and glucose production (HGP), reveals early diabetogenic changes in liver metabolism. To elucidate the mechanism of the diabetogenic effect of glucocorticoids, we treated eight healthy subjects with oral dexamethasone (DEX; 15 mg over 48 h) and measured HTGO with (2-3H)glucose and HGP with (6-3H)glucose postabsorptively and during a 2-h glucose infusion (11.1 mumol.kg-1.min-1). (2-3H)- minus (6-3H)glucose equals GC. DEX significantly increased plasma glucose, insulin, C peptide, and HTGO, while HGP was unchanged. In controls and DEX, glucose infusion suppressed HTGO (82 vs. 78%) and HGP (87 vs. 91%). DEX increased GC postabsorptively (three-fold) P less than 0.005 and during glucose infusion (P less than 0.05) but decreased metabolic clearance and glucose uptake (Rd), which eventually normalized, however. Because DEX increased HTGO (G-6-Pase) and not HGP (glycogenolysis + gluconeogenesis), we assume that DEX increases HTGO and GC in humans by activating G-6-Pase directly, rather than by expanding the glucose 6-phosphate pool. Hyperglycemia caused by peripheral effects of DEX can also contribute to an increase in GC by activating glucokinase. Therefore, measurement of glucose fluxes through G-6-Pase and GC revealed significant early effects of DEX on hepatic glucose metabolism, which are not yet reflected in HGP.

  1. Muscle mass gain observed in patients with short bowel syndrome subjected to resistance training.

    Science.gov (United States)

    Araújo, Ellen Cristini Freitas; Suen, Vivian Marques Miguel; Marchini, Julio Sergio; Vannucchi, Helio

    2008-02-01

    Few studies are available about the evaluation of resistance training in patients with protein-energy malnutrition. To assess the effects of resistance training on the recovery of nutritional status of patients with short bowel syndrome, with a small bowel remnant of less than 100 cm, 9 patients of both sexes with protein-energy malnutrition after extensive resection of the small bowel were submitted to resistance training of progressive intensity consisting of concentric and eccentric work exercises for the upper limbs, trunk, and lower limbs, with the individuality and limitations of each patients being respected. Food consumption was monitored by 24-hour food recall performed during the initial phase of the study, before and 7 and 14 weeks after physical training, and by a dietary record for a period of 3 days of oral feeding. The nutrients administered by the enteral and parenteral route were recorded. A significant increase in total arm area (P mass (P gain of lean mass.

  2. Restricted Blood Flow Exercise in Sedentary, Overweight African-American Females May Increase Muscle Strength and Decrease Endothelial Function and Vascular Autoregulation

    Directory of Open Access Journals (Sweden)

    Vernon Bond

    2017-03-01

    Full Text Available Objectives: Exercise with partially restricted blood flow is a low-load, low-intensity resistance training regimen which may have the potential to increase muscle strength in the obese, elderly and frail who are unable to do high-load training. Restricted blood flow exercise has also been shown to affect blood vessel function variably and can, therefore, contribute to blood vessel dysfunction. This pilot study tests the hypothesis that unilateral resistance training of the leg extensors with partially restricted blood flow increases muscle strength and decreases vascular autoregulation. Methods: The subjects were nine normotensive, overweight, young adult African-Americans with low cardiorespiratory fitness who underwent unilateral training of the quadriceps’ femoris muscles with partially restricted blood flow at 30% of the 1-repetition maximum (1-RM load for 3 weeks. The 1-RM load and post-occlusion blood flow to the lower leg (calf were measured during reactive hyperemia. Results: The 1-RM load increased in the trained legs from 77 ± 3 to 84 ± 4 kg (P 0.1. Post-occlusion blood flow decreased significantly in the trained legs from 19 ± 2 to 13 ± 2 mL· min-1· dL-1 (P < 0.05 and marginally in the contralateral untrained legs from 18 ± 2 to 16 ± 1 mL· min-1· dL-1 (P = 0.09. Changes in post-occlusion blood flow to the skin overlying the trained and the contralateral untrained muscles were not significant. Conclusion: These results demonstrate that restricted blood flow exercise, which results in significant gains in muscle strength, may produce decrements in endothelial dysfunction and vascular autoregulation. Future studies should determine whether pharmacopuncture plays a role in treatments for such blood vessel dysfunction.

  3. Comorbid personality disorders in subjects with panic disorder: which personality disorders increase clinical severity?

    Directory of Open Access Journals (Sweden)

    Mustafa Ozkan

    2003-03-01

    Full Text Available Personality disorders are common in subjects with panic disorder. Personality disorders have shown to affect the course of panic disorder. The purpose of this study was to examine which personality disorders effect clinical severity in subjects with panic disorder. This study included 122 adults (71 female, 41 male, who met DSM-IV criteria for panic disorder (with or without agoraphobia. Clinical assessment was conducted by using the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I, the Structured Clinical Interview for DSM-IV Axis II Personality Disorders (SCID-II and the Panic and Agoraphobia Scale (PAS, Global Assessment Functioning Scale (GAF, Beck Depression Inventory (BDI, and State-Trait Anxiety Inventory (STAI. Patients who had a history of sexual abuse were assessed with Sexual Abuse Severity Scale. Logistic regressions were used to identify predictors of suicide attempts, suicidal ideation, agoraphobia, different panic attack symptoms, sexual abuse, and early onset of disorders. The rates of comorbid Axis I and Axis II psychiatric disorders were 80.3% and 33.9%, consecutively, in patients with panic disorder. Panic disorder patients with comorbid personality disorders had more severe anxiety, depression and agoraphobia symptoms, and had earlier ages of onset, and lower levels of functioning. The rates of suicidal ideation and suicide attempts were 34.8% and 9.8%, consecutively, in subjects with panic disorder. The rate of patients with panic disorder had a history of childhood sexual abuse was 12.5%. The predictor of sexual abuse was more than one comorbid Axis II diagnosis. The predictors of suicide attempt were comorbid paranoid and borderline personality disorders, and the predictor of suicidal ideation was major depressive disorder in subjects with panic disorder. In conclusion, this study documents that comorbid personality disorders increase the clinical severity of panic disorder. Patients with more than one

  4. Endothelial and smooth muscle cells from abdominal aortic aneurysm have increased oxidative stress and telomere attrition.

    Directory of Open Access Journals (Sweden)

    Giuseppe Cafueri

    Full Text Available BACKGROUND: Abdominal aortic aneurysm (AAA is a complex multi-factorial disease with life-threatening complications. AAA is typically asymptomatic and its rupture is associated with high mortality rate. Both environmental and genetic risk factors are involved in AAA pathogenesis. Aim of this study was to investigate telomere length (TL and oxidative DNA damage in paired blood lymphocytes, aortic endothelial cells (EC, vascular smooth muscle cells (VSMC, and epidermal cells from patients with AAA in comparison with matched controls. METHODS: TL was assessed using a modification of quantitative (Q-FISH in combination with immunofluorescence for CD31 or α-smooth muscle actin to detect EC and VSMC, respectively. Oxidative DNA damage was investigated by immunofluorescence staining for 7, 8-dihydro-8-oxo-2'-deoxyguanosine (8-oxo-dG. RESULTS AND CONCLUSIONS: Telomeres were found to be significantly shortened in EC, VSMC, keratinocytes and blood lymphocytes from AAA patients compared to matched controls. 8-oxo-dG immunoreactivity, indicative of oxidative DNA damage, was detected at higher levels in all of the above cell types from AAA patients compared to matched controls. Increased DNA double strand breaks were detected in AAA patients vs controls by nuclear staining for γ-H2AX histone. There was statistically significant inverse correlation between TL and accumulation of oxidative DNA damage in blood lymphocytes from AAA patients. This study shows for the first time that EC and VSMC from AAA have shortened telomeres and oxidative DNA damage. Similar findings were obtained with circulating lymphocytes and keratinocytes, indicating the systemic nature of the disease. Potential translational implications of these findings are discussed.

  5. MUSCLE FATIGUE INCREASES METABOLIC COSTS OF ERGOMETER CYCLING WITHOUT CHANGING VO2 SLOW COMPONENT

    Directory of Open Access Journals (Sweden)

    Aivaras Ratkevicius

    2006-09-01

    Full Text Available The aim of the present study was to investigate effects of muscle fatigue on oxygen costs of ergometer cycling and slow component of pulmonary oxygen uptake (VO2 kinetics. Seven young men performed 100 drop jumps (drop height of 40 cm with 20 s of rest after each jump. After the subsequent hour of rest, they cycled at 70, 105, 140 and 175 W, which corresponded to 29.6 ± 5.4, 39.4 ± 7.0, 50.8 ± 8.4 and 65.8 ± 11.8 % of VO2peak, respectively, for 6 min at each intensity with 4-min intervals of rest in between the exercise bouts. The VO2 response to cycling after the exercise (fatigue condition was compared to ergometer cycling without prior exercise (control condition. From 3rd to 6th min of cycling at 105, 140 and 175 W, VO2 was higher (p < 0.05-0.01 when cycling in the fatigue compared to the control condition. Slow component of VO2 kinetics was observed when cycling at 175 W in the control condition (0.17 ± 0.09, l·min-1, mean ± SD, but tended to decrease in the fatigue condition (0.13 ± 0.15 l·min-1. In summary, results of the study are in agreement with the hypothesis that muscle fatigue increases oxygen costs of cycling exercise, but does not affect significantly the slow component of pulmonary oxygen uptake (VO2 kinetics

  6. Influence of gravity compensation on kinematics and muscle activation patterns during reach and retrieval in subjects with cervical spinal cord injury: an explorative study.

    Science.gov (United States)

    Kloosterman, Marieke G M; Snoek, Govert J; Kouwenhoven, Mirjam; Nene, Anand V; Jannink, Michiel J A

    2010-01-01

    Many interventions in upper-limb rehabilitation after cervical spinal cord injury (CSCI) use arm support (gravity compensation); however, its specific effects on kinematics and muscle activation characteristics in subjects with a CSCI are largely unknown. We conducted a cross-sectional explorative study to study these effects. Nine subjects with a CSCI performed two goal-directed arm movements (maximal reach, reach and retrieval) with and without gravity compensation. Angles at elbow and shoulder joints and muscle activation were measured and compared. Seven subjects reduced elbow extension (range 1.8°-4.5°) during the maximal reaching task with gravity compensation. In the reach and retrieval task with gravity compensation, all subjects decreased elbow extension (range 0.1°-11.0°). Eight subjects executed movement closer to the body. Regarding muscle activation, gravity compensation did not influence timing; however, the amplitude of activation decreased, especially in antigravity muscles, namely mean change +/- standard deviation of descending part of trapezius (18.2% +/- 37.5%), anterior part of deltoid (37.7% +/- 16.7%), posterior part of deltoid (32.0% +/- 13.9%), and long head biceps (49.6% +/- 20.0%). Clinical implications for the use of gravity compensation in rehabilitation (during activities of daily living or exercise therapy) should be further investigated with a larger population.

  7. Increased proliferation of explanted vascular smooth muscle cells: a marker presaging atherogenesis.

    Science.gov (United States)

    Absher, P M; Schneider, D J; Baldor, L C; Russell, J C; Sobel, B E

    1997-06-01

    The JCR:LA-cp homozygous cp/cp corpulent rat is genetically predisposed to develop atherosclerosis evident after 9 and 18 months of age in males and females and to manifest metabolic derangements resembling those seen in type II diabetes in humans (hyperinsulinemia, insulin resistance, hyperglycemia and hypertriglyceridemia). The present study was undertaken to determine whether vascular smooth muscle cells (SMCs) explanted from vessels destined to become atherosclerotic later in life exhibit intrinsic properties ex vivo that presage atherogenesis to provide a means for evaluating promptly intervention designed to modify it. SMCs were cultured from aortic explants of JCR:LA-cp corpulent (cp/cp) and lean control (+/+) rats of 4, 5, 6, and 9 months of age. Compared with SMCs from controls, SMCs from cp/cp rats exhibited increased proliferation, higher saturation density, increased augmentation of proliferation in response to selected mitogens and greater adherence to extracellular matrix proteins. The increased proliferative activity ex vivo anteceded by several months the development of atherosclerotic lesions in vivo. Thus, it is a promising marker in assessments of the efficacy of interventions designed to retard or prevent atherosclerosis.

  8. Metformin increases mitochondrial energy formation in L6 muscle cell cultures.

    Science.gov (United States)

    Vytla, Veeravenkata S; Ochs, Raymond S

    2013-07-12

    A popular hypothesis for the action of metformin, the widely used anti-diabetes drug, is the inhibition of mitochondrial respiration, specifically at complex I. This is consistent with metformin stimulation of glucose uptake by muscle and inhibition of gluconeogenesis by liver. Yet, mitochondrial inhibition is inconsistent with metformin stimulation of fatty acid oxidation in both tissues. In this study, we measured mitochondrial energy production in intact cells adapting an in vivo technique of phosphocreatine (PCr) formation following energy interruption ("PCr recovery") to cell cultures. Metformin increased PCr recovery from either dinitrophenol (DNP) or azide in L6 cells. We found that metformin alone had no effect on cell viability as measured by total ATP concentration, trypan blue exclusion, or 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction. However, treatments with low concentrations of DNP or azide reversibly decreased ATP concentration. Metformin increased 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction during recovery from either agent. Viability measured by trypan blue exclusion indicated that cells were intact under these conditions. We also found that metformin increased free AMP and, to a smaller extent, free ADP concentrations in cells, an action that was duplicated by a structurally unrelated AMP deaminase inhibitor. We conclude that, in intact cells, metformin can lead to a stimulation of energy formation, rather than an inhibition.

  9. Lubiprostone Increases Small Intestinal Smooth Muscle Contractions Through a Prostaglandin E Receptor 1 (EP1)-mediated Pathway.

    Science.gov (United States)

    Chan, Walter W; Mashimo, Hiroshi

    2013-07-01

    Lubiprostone, a chloride channel type 2 (ClC-2) activator, was thought to treat constipation by enhancing intestinal secretion. It has been associated with increased intestinal transit and delayed gastric emptying. Structurally similar to prostones with up to 54% prostaglandin E2 activity on prostaglandin E receptor 1 (EP1), lubiprostone may also exert EP1-mediated procontractile effect on intestinal smooth muscles. We investigated lubiprostone's effects on intestinal smooth muscle contractions and pyloric sphincter tone. Isolated murine small intestinal (longitudinal and circular) and pyloric tissues were mounted in organ baths with modified Krebs solution for isometric recording. Basal muscle tension and response to electrical field stimulation (EFS; 2 ms pulses/10 V/6 Hz/30 sec train) were measured with lubiprostone (10(-10)-10(-5) M) ± EP1 antagonist. Significance was established using Student t test and P Lubiprostone had no effect on the basal tension or EFS-induced contractions of longitudinal muscles. With circular muscles, lubiprostone caused a dose-dependent increase in EFS-induced contractions (2.11 ± 0.88 to 4.43 ± 1.38 N/g, P = 0.020) that was inhibited by pretreatment with EP1 antagonist (1.69 ± 0.70 vs. 4.43 ± 1.38 N/g, P = 0.030). Lubiprostone had no effect on circular muscle basal tension, but it induced a dose-dependent increase in pyloric basal tone (1.07 ± 0.01 to 1.97 ± 0.86 fold increase, P lubiprostone caused a dose-dependent and EP1-mediated increase in contractility of circular but not longitudinal small intestinal smooth muscles, and in basal tone of the pylorus. These findings suggest another mechanism for lubiprostone's observed clinical effects on gastrointestinal motility.

  10. Anorectal stimulation causes increased colonic motor activity in subjects with spinal cord injury.

    Science.gov (United States)

    Korsten, Mark A; Singal, Ashwani K; Monga, Amit; Chaparala, Geeta; Khan, Amir M; Palmon, Ron; Mendoza, John Reagan D; Lirio, Juan P; Rosman, Alan S; Spungen, Ann; Bauman, William A

    2007-01-01

    Difficulty with evacuation (DWE) is a major problem after spinal cord injury (SCI). Stimulation of the anal canal and lower rectum, accomplished using a gloved finger (so-called digital rectal stimulation or DRS) is often used as an adjunct to laxatives and enemas to facilitate bowel evacuation. However, the basis for the efficacy of DRS is not known. This study assessed the effect of DRS on colonic motility. Six subjects with SCI were studied several hours after a bowel care session. Colonic motility was assessed using a manometric catheter (affixed endoscopically to the splenic flexure) at baseline, during DRS, and after DRS. In addition, evacuation of barium oatmeal paste (with the consistency of stool and introduced into the rectum and descending colon) was assessed simultaneously using fluoroscopic techniques. The mean number (+/- SEM) of peristaltic waves per minute increased from 0 at baseline to 1.9 (+/- 0.5/min) during DRS and 1.5 (+/- 0.3/min) during the period immediately after cessation of DRS (P < 0.05). The mean amplitude (+/- SEM) of the peristaltic contractions was 43.4 (+/- 2.2) mmHg. The frequency of contractions, as well as amplitude of contractions, during or immediately after DRS was not significantly different. These manometric changes in response to DRS were accompanied by expulsion of barium oatmeal paste in every subject by the fifth DRS. DRS causes left-sided colonic activity in subjects with SCI. At least in part, an anorectal colonic reflex that results in enhanced contractions of the descending colon and rectum may contribute to bowel evacuation in individuals with SCI.

  11. Single dose of intra-muscular platelet rich plasma reverses the increase in plasma iron levels in exercise-induced muscle damage: A pilot study

    Directory of Open Access Journals (Sweden)

    Zekine Punduk

    2016-03-01

    Conclusion: Acute exhaustive exercise increased muscle damage markers, including plasma iron, IBC, and ferritin levels, indicating muscle damage induced by exercise. PRP administration improves inflammation by reversing the increase in the iron levels post-exercise without displaying any myotoxicity and may have a role to play in the recovery of exercise-induced muscle damage.

  12. PUFAs acutely affect triacylglycerol-derived skeletal muscle fatty acid uptake and increase postprandial insulin sensitivity

    NARCIS (Netherlands)

    Jans, A.; Konings, E.; Goossens, G.H.; Bouwman, F.G.; Moors, C.C.; Boekschoten, M.V.; Afman, L.A.; Muller, M.R.; Mariman, E.C.; Blaak, E.E.

    2012-01-01

    Background: Dietary fat quality may influence skeletal muscle lipid processing and fat accumulation, thereby modulating insulin sensitivity. Objective: The objective was to examine the acute effects of meals with various fatty acid (FA) compositions on skeletal muscle FA processing and postprandial

  13. Single dose of fluoxetine increases muscle activation in chronic stroke patients.

    NARCIS (Netherlands)

    van Genderen, Hanneke Irene; Nijlant, Juliette M.M.; van Putten, Michel Johannes Antonius Maria; Movig, Kris L.L.; IJzerman, Maarten Joost

    2009-01-01

    Objectives: This pilot study explores the influence of a single dose of fluoxetine (20 mg) on the muscle activation patterns and functional ability of the muscles in the lower part of the arm in chronic stroke patients. Methods: A crossover, placebo-controlled clinical trial was conducted in 10

  14. Chronic transformation of muscle in spasticity: a peripheral contribution to increased tone.

    OpenAIRE

    Hufschmidt, A; Mauritz, K H

    1985-01-01

    Mechanical properties of relaxed lower leg muscles were assessed by torque measurements during imposed constant velocity dorsiflexion-plantarflexion cycles. At low angular velocities, they exhibited an elastic and an energy-consuming, velocity-independent (plastic) resistance. In most patients with long-standing spasticity, both of these were enhanced. The results support the hypothesis of secondary structural changes of muscles in spasticity.

  15. Increased health risk in subjects with high self-reported seasonality.

    Directory of Open Access Journals (Sweden)

    Nicolas M Øyane

    Full Text Available BACKGROUND: Seasonal variations in mood and behaviour, termed seasonality, are commonly reported in the general population. As a part of a large cross-sectional health survey in Hordaland, Norway, we investigated the relationship between seasonality, objective health measurements and health behaviours. METHODOLOGY/PRINCIPAL FINDINGS: A total of 11,545 subjects between 40-44 years old participated, completing the Global Seasonality Score, measuring seasonality. Waist/hip circumference, BMI and blood pressure were measured, and blood samples were analyzed for total cholesterol, HDL cholesterol, triglycerides and glucose. Subjects also completed a questionnaire on miscellaneous health behaviours (exercise, smoking, alcohol consumption. Hierarchical linear regression analyses were used to investigate associations between seasonality and objective health measurements, while binary logistic regression was used for analysing associations between seasonality and health behaviours. Analyses were adjusted for sociodemographic factors, month of questionnaire completion and sleep duration. Seasonality was positively associated with high waist-hip-ratio, BMI, triglyceride levels, and in men high total cholesterol. Seasonality was negatively associated with HDL cholesterol. In women seasonality was negatively associated with prevalence of exercise and positively associated with daily cigarette smoking. CONCLUSIONS/SIGNIFICANCE: High seasonality was associated with objective health risk factors and in women also with health behaviours associated with an increased risk for cardiovascular disease.

  16. Intensive blood pressure lowering increases cerebral blood flow in older subjects with hypertension.

    Science.gov (United States)

    Tryambake, Dinesh; He, Jiabao; Firbank, Michael J; O'Brien, John T; Blamire, Andrew M; Ford, Gary A

    2013-06-01

    Hypertension is associated with reduced cerebral blood flow (CBF). Intensive (blood pressure (BP) lowering in older people might give greater reduction in cardiovascular risk, but there are concerns that this might produce hypoperfusion which may precipitate falls and possibly stroke. We determined the effect of intensive compared with usual BP lowering on CBF in hypertensive older subjects. Individuals aged >70 years with a history of systolic hypertension on 1 or no BP lowering drugs were recruited from primary care (n=37; age, 75±4 years; systolic BP, >150 mm Hg) and randomized to receive intensive (target BP, hypertension increases CBF, compared with BP lowering to usual target. These findings suggest hypertension in older people shifts the autoregulatory CBF curve rightward and downward and is reversible with BP lowering.

  17. Trunk muscle co-contraction increases during fatiguing, isometric, lateral bend exertions. Possible implications for spine stability.

    Science.gov (United States)

    Potvin, J R; O'Brien, P R

    1998-04-01

    Surface electromyographic activities were recorded from bilateral trunk muscles as test participants maintained a 50% maximum, voluntary, isometric, lateral bend contraction to volitional exhaustion. To challenge the trunk with a prolonged lateral bend task and observe the responses of the agonist and antagonist muscles to the resulting fatigue. Lateral bend exertions of the trunk have been identified as a risk factor for injury to spine tissues. However, little is known about the response of spine muscles to fatigue and the subsequent implications for spine stability, joint loading, and tissue injury. Surface electromyography provides a window on muscle loading and progressive fatigue. Eleven male participants performed a set of maximum lateral bend exertions at the start of the trial, then maintained an upright standing posture while resisting 50% of the maximum moment until volitional exhaustion, then performed another set of maximum contractions. All contractions were isometric. Measurements were made, throughout each contraction, of the lateral bend moment and abdominal and trunk extensor electromyographic activities at six bilateral surface electromyography sites. Electromyographic amplitude and mean power frequency were calculated with 500-millisecond segments recorded serially every 800 milliseconds. Mean values were calculated with data from the first and last 5% of the trial durations. Statistics determined if fatigue had a significant effect on maximum moment and the electromyographic statistics for each muscle site. Fatigue resulted in a significant decrease in maximum lateral bend moment and increase in moment variability. Decreases in mean power frequency, indicating fatigue, were observed in three agonists (the trunk extensors) and one antagonist muscle. Unfatigued agonist electromyographic amplitudes correlated well with the mechanical advantage of muscles to generate lateral bend moments. Unfatigued antagonist activities were low except for the

  18. Lung volume recruitment acutely increases respiratory system compliance in individuals with severe respiratory muscle weakness.

    Science.gov (United States)

    Molgat-Seon, Yannick; Hannan, Liam M; Dominelli, Paolo B; Peters, Carli M; Fougere, Renee J; McKim, Douglas A; Sheel, A William; Road, Jeremy D

    2017-01-01

    The aim of the present study was to determine whether lung volume recruitment (LVR) acutely increases respiratory system compliance (Crs) in individuals with severe respiratory muscle weakness (RMW). Individuals with RMW resulting from neuromuscular disease or quadriplegia (n=12) and healthy controls (n=12) underwent pulmonary function testing and the measurement of Crs at baseline, immediately after, 1 h after and 2 h after a single standardised session of LVR. The LVR session involved 10 consecutive supramaximal lung inflations with a manual resuscitation bag to the highest tolerable mouth pressure or a maximum of 50 cmH2O. Each LVR inflation was followed by brief breath-hold and a maximal expiration to residual volume. At baseline, individuals with RMW had lower Crs than controls (37±5 cmH2O versus 109±10 mL·cmH2O(-1), p0.05). LVR had no significant effect on measures of pulmonary function at any time point in either group (all p>0.05). During inflations, mean arterial pressure decreased significantly relative to baseline by 10.4±2.8 mmHg and 17.3±3.0 mmHg in individuals with RMW and controls, respectively (both p<0.05). LVR acutely increases Crs in individuals with RMW. However, the high airway pressures during inflations cause reductions in mean arterial pressure that should be considered when applying this technique.

  19. Increased intramyocellular lipid/impaired insulin sensitivity is associated with altered lipid metabolic genes in muscle of high responders to a high-fat diet.

    Science.gov (United States)

    Kakehi, Saori; Tamura, Yoshifumi; Takeno, Kageumi; Sakurai, Yuko; Kawaguchi, Minako; Watanabe, Takahiro; Funayama, Takashi; Sato, Fumihiko; Ikeda, Shin-Ichi; Kanazawa, Akio; Fujitani, Yoshio; Kawamori, Ryuzo; Watada, Hirotaka

    2016-01-01

    The accumulation of intramyocellular lipid (IMCL) is recognized as an important determinant of insulin resistance, and is increased by a high-fat diet (HFD). However, the effects of HFD on IMCL and insulin sensitivity are highly variable. The aim of this study was to identify the genes in muscle that are related to this inter-individual variation. Fifty healthy men were recruited for this study. Before and after HFD for 3 days, IMCL levels in the tibialis anterior were measured by (1)H magnetic resonance spectroscopy, and peripheral insulin sensitivity was evaluated by glucose infusion rate (GIR) during the euglycemic-hyperinsulinemic clamp. Subjects who showed a large increase in IMCL and a large decrease in GIR by HFD were classified as high responders (HRs), and subjects who showed a small increase in IMCL and a small decrease in GIR were classified as low responders (LRs). In five subjects from each group, the gene expression profile of the vastus lateralis muscle was analyzed by DNA microarray analysis. Before HFD, gene expression profiles related to lipid metabolism were comparable between the two groups. Gene Set Enrichment Analysis demonstrated that five gene sets related to lipid metabolism were upregulated by HFD in the HR group but not in the LR group. Changes in gene expression patterns were confirmed by qRT-PCR using more samples (LR, n = 9; HR, n = 11). These results suggest that IMCL accumulation/impaired insulin sensitivity after HFD is closely associated with changes in the expression of genes related to lipid metabolism in muscle. Copyright © 2016 the American Physiological Society.

  20. Moringa Oleifera Leaf Increases Insulin Secretion after Single Dose Administration: A Preliminary Study in Healthy Subjects.

    Science.gov (United States)

    Anthanont, Pimjai; Lumlerdkij, Natchagorn; Akarasereenont, Pravit; Vannasaeng, Sathit; Sriwijitkamol, Apiradee

    2016-03-01

    Herbal medicine has long been used as an alternative medicine for treatment of type 2 diabetes mellitus (T2DM). Recently, Moringa oleifera (MO or ma-rum in Thai) leaf has been widely used in T2DM patients. Several studies in diabetes rat model have shown that MO had effect on glucose metabolism. However study in humans is lacking. Examine effects of MO on plasma glucose and insulin secretion. Ten healthy volunteers were enrolled in this study (mean age 29 ± 5 years; BMI 20.6 ± 1.5 kg/m2; FPG 81 ± 5 mg/dl). After an overnight fast and every two weeks, subjects received an oral dose of MO at increasing dosages of 0, 1, 2, and 4 g. Plasma glucose (PG) and insulin were collected at baseline and at 0.5, 1, 1.5, 2, 4, and 6 hours after each MO dosage administration. Insulin secretion rate was measured using area under the curve (AUC) of insulin and AUC of insulin/glucose ratio. After doses of 0, 1, 2, and 4 g MO, mean plasma insulin increased (2.3 ± 0.9, 2.7 ± 1.0, 3.3 ± 1.4, and 4.1 ± 1.7 μU/ml, respectively) despite there being no differences in mean PG (77 ± 6, 78 ± 5, 79 ± 6, and 79 ± 5 mg/dl, respectively). AUC of insulin was greater after high-dose MO (4 g) than after baseline or low-dose MO capsule (1 g) (24.0 ± 3.5 vs. 14.5 ± 1.8 or 16.1 ± 2.0, respectively; p = 0.03), while there was no difference in AUC of glucose. Accordingly, insulin secretion rate represented by AUC of insulin/glucose ratio after high-dose MO was significantly increased by 74% (P = 0.041), as compared with that of baseline. We concluded that high-dose (4 g) MO leaf powder capsules significantly increased insulin secretion in healthy subjects. These results suggest that MO leaf may be a potential agent in the treatment of type 2 diabetes. Further studies of MO in patients with T2DM are needed.

  1. Erythropoietin over-expression protects against diet-induced obesity in mice through increased fat oxidation in muscles

    DEFF Research Database (Denmark)

    Hojman, Pernille; Brolin, Camilla; Gissel, Hanne

    2009-01-01

    patients. Thus we applied the EPO over-expression model to investigate the metabolic effect of EPO in vivo.At 12 weeks, EPO expression resulted in a 23% weight reduction (Pobese mice; thus the mice weighed 21.9+/-0.8 g (control, normal diet,) 21.9+/-1.4 g (EPO, normal diet), 35...... and inflammation were increased in muscles in response to EPO expression, while genes involved in glucose metabolism were down-regulated. In addition, muscular fat oxidation was increased 1.8-fold in both the EPO transfected and contralateral muscles.In conclusion, we have shown that EPO when expressed in supra......-physiological levels has substantial metabolic effects including protection against diet-induced obesity and normalisation of glucose sensitivity associated with a shift to increased fat metabolism in the muscles....

  2. Aceneuramic Acid Extended Release Administration Maintains Upper Limb Muscle Strength in a 48-week Study of Subjects with GNE Myopathy: Results from a Phase 2, Randomized, Controlled Study

    Science.gov (United States)

    Argov, Zohar; Caraco, Yoseph; Lau, Heather; Pestronk, Alan; Shieh, Perry B.; Skrinar, Alison; Koutsoukos, Tony; Ahmed, Ruhi; Martinisi, Julia; Kakkis, Emil

    2016-01-01

    Background: GNE Myopathy (GNEM) is a progressive adult-onset myopathy likely caused by deficiency of sialic acid (SA) biosynthesis. Objective: Evaluate the safety and efficacy of SA (delivered by aceneuramic acid extended-release [Ace-ER]) as treatment for GNEM. Methods: A Phase 2, randomized, double-blind, placebo-controlled study evaluating Ace-ER 3 g/day or 6 g/day versus placebo was conducted in GNEM subjects (n = 47). After the first 24 weeks, placebo subjects crossed over to 3 g/day or 6 g/day for 24 additional weeks (dose pre-assigned during initial randomization). Assessments included serum SA, muscle strength by dynamometry, functional assessments, clinician- and patient-reported outcomes, and safety. Results: Dose-dependent increases in serum SA levels were observed. Supplementation with Ace-ER resulted in maintenance of muscle strength in an upper extremity composite (UEC) score at 6 g/day compared with placebo at Week 24 (LS mean difference +2.33 kg, p = 0.040), and larger in a pre-specified subgroup able to walk ≥200 m at Screening (+3.10 kg, p = 0.040). After cross-over, a combined 6 g/day group showed significantly better UEC strength than a combined 3 g/day group (+3.46 kg, p = 0.0031). A similar dose-dependent response was demonstrated within the lower extremity composite score, but was not significant (+1.06 kg, p = 0.61). The GNEM-Functional Activity Scale demonstrated a trend improvement in UE function and mobility in a combined 6 g/day group compared with a combined 3 g/day group. Patients receiving Ace-ER tablets had predominantly mild-to-moderate AEs and no serious adverse events. Conclusions: This is the first clinical study to provide evidence that supplementation with SA delivered by Ace-ER may stabilize muscle strength in individuals with GNEM and initiating treatment earlier in the disease course may lead to better outcomes. PMID:27854209

  3. Amla Enhances Mitochondrial Spare Respiratory Capacity by Increasing Mitochondrial Biogenesis and Antioxidant Systems in a Murine Skeletal Muscle Cell Line

    Directory of Open Access Journals (Sweden)

    Hirotaka Yamamoto

    2016-01-01

    Full Text Available Amla is one of the most important plants in Indian traditional medicine and has been shown to improve various age-related disorders while decreasing oxidative stress. Mitochondrial dysfunction is a proposed cause of aging through elevated oxidative stress. In this study, we investigated the effects of Amla on mitochondrial function in C2C12 myotubes, a murine skeletal muscle cell model with abundant mitochondria. Based on cell flux analysis, treatment with an extract of Amla fruit enhanced mitochondrial spare respiratory capacity, which enables cells to overcome various stresses. To further explore the mechanisms underlying these effects on mitochondrial function, we analyzed mitochondrial biogenesis and antioxidant systems, both proposed regulators of mitochondrial spare respiratory capacity. We found that Amla treatment stimulated both systems accompanied by AMPK and Nrf2 activation. Furthermore, we found that Amla treatment exhibited cytoprotective effects and lowered reactive oxygen species (ROS levels in cells subjected to t-BHP-induced oxidative stress. These effects were accompanied by increased oxygen consumption, suggesting that Amla protected cells against oxidative stress by using enhanced spare respiratory capacity to produce more energy. Thus we identified protective effects of Amla, involving activation of mitochondrial function, which potentially explain its various effects on age-related disorders.

  4. S6K1 Is Required for Increasing Skeletal Muscle Force during Hypertrophy

    Directory of Open Access Journals (Sweden)

    Manuela Marabita

    2016-10-01

    Full Text Available Loss of skeletal muscle mass and force aggravates age-related sarcopenia and numerous pathologies, such as cancer and diabetes. The AKT-mTORC1 pathway plays a major role in stimulating adult muscle growth; however, the functional role of its downstream mediators in vivo is unknown. Here, we show that simultaneous inhibition of mTOR signaling to both S6K1 and 4E-BP1 is sufficient to reduce AKT-induced muscle growth and render it insensitive to the mTORC1-inhibitor rapamycin. Surprisingly, lack of mTOR signaling to 4E-BP1 only, or deletion of S6K1 alone, is not sufficient to reduce muscle hypertrophy or alter its sensitivity to rapamycin. However, we report that, while not required for muscle growth, S6K1 is essential for maintaining muscle structure and force production. Hypertrophy in the absence of S6K1 is characterized by compromised ribosome biogenesis and the formation of p62-positive protein aggregates. These findings identify S6K1 as a crucial player for maintaining muscle function during hypertrophy.

  5. S6K1 Is Required for Increasing Skeletal Muscle Force during Hypertrophy.

    Science.gov (United States)

    Marabita, Manuela; Baraldo, Martina; Solagna, Francesca; Ceelen, Judith Johanna Maria; Sartori, Roberta; Nolte, Hendrik; Nemazanyy, Ivan; Pyronnet, Stéphane; Kruger, Marcus; Pende, Mario; Blaauw, Bert

    2016-10-04

    Loss of skeletal muscle mass and force aggravates age-related sarcopenia and numerous pathologies, such as cancer and diabetes. The AKT-mTORC1 pathway plays a major role in stimulating adult muscle growth; however, the functional role of its downstream mediators in vivo is unknown. Here, we show that simultaneous inhibition of mTOR signaling to both S6K1 and 4E-BP1 is sufficient to reduce AKT-induced muscle growth and render it insensitive to the mTORC1-inhibitor rapamycin. Surprisingly, lack of mTOR signaling to 4E-BP1 only, or deletion of S6K1 alone, is not sufficient to reduce muscle hypertrophy or alter its sensitivity to rapamycin. However, we report that, while not required for muscle growth, S6K1 is essential for maintaining muscle structure and force production. Hypertrophy in the absence of S6K1 is characterized by compromised ribosome biogenesis and the formation of p62-positive protein aggregates. These findings identify S6K1 as a crucial player for maintaining muscle function during hypertrophy. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  6. Inspiratory muscle strength in subjects with tetraplegia: viability of evaluation through the measurement of maximal inspiratory pressure

    Directory of Open Access Journals (Sweden)

    Marlene Aparecida Moreno

    Full Text Available Objective To analyze the values of maximal inspiratory pressure (MIP and sniff nasal inspiratory pressure (SNIP and to verify the existence of concordance between the two evaluation methodologies, in subjects with tetraplegia. Materials and methods Cross-sectional study with 17 tetraplegic men, aged 30.42 ± 7.67 years, who underwent MIP and SNIP evaluation using a respiratory pressure meter. Results The MIP and SNIP values obtained showed no difference when compared to each other (88.42 ± 29.39 vs. 86.68 ± 25.40 cmH2O, respectively. They were, however, significantly lower compared to the predicted values (MIP = 128.92 ± 7.18; SNIP = 114.11 ± 3.19 cmH2O, with the MIP values presenting correlation (r2 = 0.94; p < 0.0001 and concordance with those of the SNIP. Conclusions Both the MIP and SNIP values obtained were lower than the predicted values, indicating a reduction in inspiratory muscle strength (IMS. Both techniques showed correlation and concordance, suggesting that MIP can be used as a noninvasive method for IMS evaluation in this population.

  7. Physico-chemical characteristics of Longissimus lumborum muscle in goats subjected to halal slaughter and anesthesia (halothane) pre-slaughter.

    Science.gov (United States)

    Sabow, Azad Behnan; Sazili, Awis Qurni; Zulkifli, Idrus; Goh, Yong Meng; Ab Kadir, Mohd Zainal Abidin; Adeyemi, Kazeem Dauda

    2015-12-01

    This study assessed the effect of halal slaughter and anesthesia pre-slaughter followed by bleeding on meat quality characteristics of goats. Eleven male Boer cross goats were divided into two groups and subjected to either halal slaughter (HS) or anesthesia with halothane and propofol pre-slaughter (AS). At pre-rigor, HS had significantly lower (P < 0.05) muscle pH and glycogen than AS. However, no significant difference was observed in the pH and glycogen content between the treatments on 1, 3 and 7 days post mortem. The drip loss of HS was significantly lower (P < 0.05) than that of AS at all aging periods. Treatment had no effect on sarcomere length, myofibrillar fragmentation index and shear force values, loss of thiol groups and degradation of major myofibrillar proteins. It can be concluded that HS did not have deleterious effect on meat quality traits of goat when compared to AS. © 2015 Japanese Society of Animal Science.

  8. Administration of soluble activin receptor 2B increases bone and muscle mass in a mouse model of osteogenesis imperfecta

    Science.gov (United States)

    DiGirolamo, Douglas J.; Singhal, Vandana; Chang, Xiaoli; Lee, Se-Jin; Germain-Lee, Emily L.

    2015-01-01

    Osteogenesis imperfecta (OI) comprises a group of heritable connective tissue disorders generally defined by recurrent fractures, low bone mass, short stature and skeletal fragility. Beyond the skeletal complications of OI, many patients also report intolerance to physical activity, fatigue and muscle weakness. Indeed, recent studies have demonstrated that skeletal muscle is also negatively affected by OI, both directly and indirectly. Given the well-established interdependence of bone and skeletal muscle in both physiology and pathophysiology and the observations of skeletal muscle pathology in patients with OI, we investigated the therapeutic potential of simultaneous anabolic targeting of both bone and skeletal muscle using a soluble activin receptor 2B (ACVR2B) in a mouse model of type III OI (oim). Treatment of 12-week-old oim mice with ACVR2B for 4 weeks resulted in significant increases in both bone and muscle that were similar to those observed in healthy, wild-type littermates. This proof of concept study provides encouraging evidence for a holistic approach to treating the deleterious consequences of OI in the musculoskeletal system. PMID:26161291

  9. Influence of gravity compensation on kinematics and muscle activation patterns during reach and retrieval in subjects with cervical spinal cord injury An explorative study

    NARCIS (Netherlands)

    Kloosterman, Marieke G. M.; Snoek, Govert J.; Kouwenhoven, Mirjam; Nene, Anand V.; Jannink, Michiel J. A.

    2010-01-01

    Many interventions in upper-limb rehabilitation after cervical spinal cord injury (CSCI) use arm support (gravity compensation), however, its specific effects on kinematics and muscle activation characteristics in subjects with a CSCI are largely unknown We conducted a cross-sectional explorative

  10. Formoterol attenuates increased oxidative stress and myosin protein loss in respiratory and limb muscles of cancer cachectic rats

    Directory of Open Access Journals (Sweden)

    Anna Salazar-Degracia

    2017-12-01

    Full Text Available Muscle mass loss and wasting are characteristic features of patients with chronic conditions including cancer. Therapeutic options are still scarce. We hypothesized that cachexia-induced muscle oxidative stress may be attenuated in response to treatment with beta2-adrenoceptor-selective agonist formoterol in rats. In diaphragm and gastrocnemius of tumor-bearing rats (108 AH-130 Yoshida ascites hepatoma cells inoculated intraperitoneally with and without treatment with formoterol (0.3 mg/kg body weight/day for seven days, daily subcutaneous injection, redox balance (protein oxidation and nitration and antioxidants and muscle proteins (1-dimensional immunoblots, carbonylated proteins (2-dimensional immunoblots, inflammatory cells (immunohistochemistry, and mitochondrial respiratory chain (MRC complex activities were explored. In the gastrocnemius, but not the diaphragm, of cancer cachectic rats compared to the controls, protein oxidation and nitration levels were increased, several functional and structural proteins were carbonylated, and in both study muscles, myosin content was reduced, inflammatory cell counts were greater, while no significant differences were seen in MRC complex activities (I, II, and IV. Treatment of cachectic rats with formoterol attenuated all the events in both respiratory and limb muscles. In this in vivo model of cancer-cachectic rats, the diaphragm is more resistant to oxidative stress. Formoterol treatment attenuated the rise in oxidative stress in the limb muscles, inflammatory cell infiltration, and the loss of myosin content seen in both study muscles, whereas no effects were observed in the MRC complex activities. These findings have therapeutic implications as they demonstrate beneficial effects of the beta2 agonist through decreased protein oxidation and inflammation in cachectic muscles, especially the gastrocnemius.

  11. Shikonin increases glucose uptake in skeletal muscle cells and improves plasma glucose levels in diabetic Goto-Kakizaki rats.

    Directory of Open Access Journals (Sweden)

    Anette I Öberg

    Full Text Available BACKGROUND: There is considerable interest in identifying compounds that can improve glucose homeostasis. Skeletal muscle, due to its large mass, is the principal organ for glucose disposal in the body and we have investigated here if shikonin, a naphthoquinone derived from the Chinese plant Lithospermum erythrorhizon, increases glucose uptake in skeletal muscle cells. METHODOLOGY/PRINCIPAL FINDINGS: Shikonin increases glucose uptake in L6 skeletal muscle myotubes, but does not phosphorylate Akt, indicating that in skeletal muscle cells its effect is medaited via a pathway distinct from that used for insulin-stimulated uptake. Furthermore we find no evidence for the involvement of AMP-activated protein kinase in shikonin induced glucose uptake. Shikonin increases the intracellular levels of calcium in these cells and this increase is necessary for shikonin-mediated glucose uptake. Furthermore, we found that shikonin stimulated the translocation of GLUT4 from intracellular vesicles to the cell surface in L6 myoblasts. The beneficial effect of shikonin on glucose uptake was investigated in vivo by measuring plasma glucose levels and insulin sensitivity in spontaneously diabetic Goto-Kakizaki rats. Treatment with shikonin (10 mg/kg intraperitoneally once daily for 4 days significantly decreased plasma glucose levels. In an insulin sensitivity test (s.c. injection of 0.5 U/kg insulin, plasma glucose levels were significantly lower in the shikonin-treated rats. In conclusion, shikonin increases glucose uptake in muscle cells via an insulin-independent pathway dependent on calcium. CONCLUSIONS/SIGNIFICANCE: Shikonin increases glucose uptake in skeletal muscle cells via an insulin-independent pathway dependent on calcium. The beneficial effects of shikonin on glucose metabolism, both in vitro and in vivo, show that the compound possesses properties that make it of considerable interest for developing novel treatment of type 2 diabetes.

  12. Light-load resistance exercise increases muscle protein synthesis and hypertrophy signaling in elderly men

    DEFF Research Database (Denmark)

    Agergaard, Jakob; Bülow, Jacob; Jensen, Jacob K

    2017-01-01

    INTRODUCTION: The present study investigated whether well-tolerated light-load resistance exercise (LL-RE) affects skeletal muscle fractional synthetic rate (FSR) and anabolic intracellular signaling as a way to counteract age-related loss of muscle mass. METHODS: Untrained healthy men (age: +65...... and 12g whey protein at 7 hours post-exercise; N=10) or placebo (4g maltodextrin/hour; N=10). Quadriceps muscle biopsies were taken at 0, 3, 7 and 10 hours post-exercise from both the resting and exercised leg. Myofibrillar-FSR and activity of select targets from the mTORC1-signalling cascade were...

  13. Simple artificial training device for respiratory muscle strength and lung volumes in healthy young male and female subjects: A pilot study.

    Science.gov (United States)

    Leelarungrayub, Jirakrit; Pinkaew, Decha; Yankai, Araya; Chautrakoon, Busaba; Kuntain, Rungtiwa

    2017-10-01

    The aim of this study was to evaluate the efficiency of a simple artificial device for respiratory muscle strength training and lung volumes using either combined or non-combined exercise with elastic bands in healthy young participants. Forty healthy young participants (20 male and 20 female) aged 19-24 years old were randomized into two main experiments with four sub-groups; (1) artificial device (n = 10) & standard device (n = 10) training, and (2) artificial device training combined with elastic band (EB) exercise (n = 10) & standard device training combined with EB (n = 10) exercise. Respiratory muscle strength with maximal peak inspiratory pressure (PImax), and lung volumes; tidal volume (TV), inspiratory reserve volume (IRV), expiratory reserve volume (ERV) and vital capacity (VC) were evaluated before and after training once daily for 3 weeks. Moreover, the peak dyspnea score and vital sign parameters were compared between the experimental groups after final training. All parameters had no statistical differences (p > 0.5) between the training devices alone and those combined with EB exercise prior to any experiments. Results from the first experiment showed that training with an artificial device increased all parameters (PImax, VC, IRV, ERV) significantly (p < 0.05), except for TV, when compared to pre training results, which were the same as those in the standard device training group. No statistical difference was shown between these groups after the training period had been performed. Furthermore, results of applying artificial device training combined with EB exercise showed a significant increase in all parameters, except for TV, and they were the same as the increased results in training with the standard device combined with EB exercise. There was no significant difference of data between these groups after the training period. Finally, the results of peak dyspnea score and all vital sign parameters from using the artificial device

  14. Do Negative Affect Characteristics and Subjective Memory Concerns Increase Risk for Late Life Anxiety?

    Science.gov (United States)

    Wilkes, Chelsey M.; Wilson, Helen W.; Woodard, John L.; Calamari, John E.

    2013-01-01

    To better understand the development and exacerbation of late-life anxiety, we tested a risk model positing that trait negative affect (NA) characteristics would interact with cognitive functioning, thereby increasing some older adults’ risk for increased anxiety symptoms. The moderator-mediator model consisted of measures of NA, cognitive functioning, and their interaction, as predictors of later Hamilton Anxiety Rating Scale scores (HARS) via a mediational process, subjective memory concerns (SMCs). Older adults (aged 65-years and over; Mage = 76.7 years, SD = 6.90 years) completed evaluations four times over approximately 18 months. A latent growth curve model including Anxiety Sensitivity Index total score (ASI), Mattis Dementia Rating Scale-2 (DRS) total raw score, the ASI x DRS interaction, a SMC measure as mediator, HARS intercept (scores at times 3 and 4), and HARS slope provided good fit The ASI x DRS-2 interaction at Time 1 predicted HARS slope score (β = −.34, p <.05). When ASI score was high, stronger cognitive functioning was associated with fewer anxiety symptoms. The indirect effect of ASI score predicting HARS score 18-months later through the SMC mediator was statistically significant (β = .08, p < .05). Results suggest that the cognitive functioning changes associated with aging might contribute to the development of anxiety symptoms in older adults with specific NA traits. Implications for predicting and preventing late life anxiety disorders are discussed. PMID:23623610

  15. Dynamic vessel wall properties and their reproducibility in subjects with increased cardiovascular risk.

    Science.gov (United States)

    van den Berkmortel, F; Wollersheim, H; van Langen, H; Thien, T

    1998-06-01

    To determine reproducibility figures of dynamic arterial wall properties such as cross-sectional compliance (CC) and distensibility (DC) in subjects with increased cardiovascular risk, in comparison with healthy adults. A total of 34 persons were divided into three groups with varying cardiovascular risk factors. Diameters (D) and diameter changes (deltaD) during the heart cycle of both common carotid (CCA) and right common femoral (CFA) arteries were measured by a vessel wall movement detector system. Blood pressures (BP) were recorded non-invasively by a semi-automated oscillometric device. CC (=piD(deltaD/2deltaP) in unit mm2/kPa) and DC (=2deltaD/D)/deltaP in unit 10(-3)/kPa) were calculated from the above-mentioned parameters. Measurements were performed twice during one visit and twice again with a time interval of at least 3 days to determine intra-observer intra- and intersession variability. Reproducibility figures of CC and DC of the CCA varied between 8 and 12%, and between 13 and 22% for the CFA. Intra-observer intra- and intersession variability were similar in the three groups. In our studies the reproducibility of dynamic vascular wall properties determined by ultrasound was good. Despite differences in the absolute values for CC and DC in groups with increased cardiovascular risk, mean reproducibility figures remained at a similar level (8-12%) as in healthy volunteers.

  16. Effect of Increased Cyclic AMP Concentration on Muscle Protein Synthesis and Beta-Adrenergic Receptor Expression in Chicken Skeletal Muscle Cells in Culture

    Science.gov (United States)

    Young, R. B.; Vaughn, J. R.; Bridge, K. Y.; Smith, C. K.

    1998-01-01

    Analogies of epinephrine are known to cause hypertrophy of skeletal muscle when fed to animals. These compounds presumably exert their physiological action through interaction with the P-adrenergic receptor. Since the intracellular signal generated by the Beta-adrenergic receptor is cyclic AMP (cAMP), experiments were initiated in cell culture to determine if artificial elevation of cAMP by treatment with forskolin would alter muscle protein metabolism and P-adrenergic receptor expression. Chicken skeletal muscle cells after 7 days in culture were treated with 0.2-30 micrometers forskolin for a total of three days. At the end of the treatment period, both the concentration of cAMP and the quantity of myosin heavy chain (MHC) were measured. Concentration of cAMP in forskolin-treated cells increased up to 10-fold in a dose dependent manner. In contrast, the quantity of MHC was increased approximately 50% above control cells at 0.2 micrometers forskolin, but exhibited a gradual decline at higher levels of forskolin so that the quantity of MHC in cells treated with 30 micrometers forskolin was not significantly different from controls. Curiously, the intracellular concentration of cAMP which elicited the maximum increase in the quantity of MHC was only 40% higher than cAMP concentration in control cells.

  17. Progressive resistance-loaded voluntary wheel running increases hypertrophy and differentially affects muscle protein synthesis, ribosome biogenesis, and proteolytic markers in rat muscle.

    Science.gov (United States)

    Mobley, C B; Holland, A M; Kephart, W C; Mumford, P W; Lowery, R P; Kavazis, A N; Wilson, J M; Roberts, M D

    2018-02-01

    We examined if 6 weeks of progressive resistance-loaded voluntary wheel running in rats induced plantaris, soleus, and/or gastrocnemius hypertrophy and/or affected markers of translational efficiency, ribosome biogenesis, and markers of proteolysis. For 6 weeks, 8 male Sprague-Dawley rats (~9-10 weeks of age, ~300-325 g) rats were assigned to the progressive resistance-loaded voluntary wheel running model (EX), and ten rats were not trained (SED). For EX rats, the wheel-loading paradigm was as follows - days 1-7: free-wheel resistance, days 8-15: wheel resistance set to 20%-25% body mass, days 16-24: 40% body mass, days 25-32: 60% body mass, days 33-42: 40% body mass. Following the intervention, muscles were analysed for markers of translational efficiency, ribosome biogenesis, and muscle proteolysis. Raw gastrocnemius mass (+13%, p < .01), relative (body mass-corrected) gastrocnemius mass (+16%, p < .001), raw plantaris mass (+13%, p < .05), and relative plantaris mass (+15%, p < .01) were greater in EX vs. SED rats. In spite of gastrocnemius hypertrophy, EX animals presented a 54% decrease in basal muscle protein synthesis levels (p < .01), a 125% increase in pan 4EBP1 levels (p < .001) and a 31% decrease in pan eIF4E levels (p < .05). However, in relation to SED animals, EX animals presented a 70% increase in gastrocnemius c-Myc protein levels (p < .05). Most markers of translational efficiency and ribosome biogenesis were not altered in the plantaris or soleus muscles of EX vs. SED animals. Gastrocnemius F-box protein 32 and poly-ubiquinated protein levels were approximately 150% and 200% greater in SED vs. EX rats (p < .001). These data suggest that the employed resistance training model increases hind limb muscle hypertrophy, and this may be mainly facilitated through reductions in skeletal muscle proteolysis, rather than alterations in ribosome biogenesis or translational efficiency. © 2017 Blackwell Verlag GmbH.

  18. Heel-strike in walking: assessment of potential sources of intra- and inter-subject variability in the activation patterns of muscles stabilizing the knee joint.

    Science.gov (United States)

    Huber, Cora; Federolf, Peter; Nüesch, Corina; Cattin, Philippe C; Friederich, Niklaus F; Tscharner, Vinzenz von

    2013-04-26

    The electromyographic (EMG) signal is known to show large intra-subject and inter-subject variability. Adaptation to, and preparation for, the heel-strike event have been hypothesized to be major sources of EMG variability in walking. The aim of this study was to assess these hypotheses using a principal component analysis (PCA). Two waveform shapes with distinct characteristic features were proposed based on conceptual considerations of how the neuro-muscular system might prepare for, or adapt to, the heel-strike event. PCA waveforms obtained from knee muscle EMG signals were then compared with the predicted characteristic features of the two proposed waveforms. Surface EMG signals were recorded for ten healthy adult female subjects during level walking at a self-selected speed, for the following muscles; rectus femoris, vastus medialis, vastus lateralis, semitendinosus, and biceps femoris. For a period of 200 ms before and after heel-strike, EMG power was extracted using a wavelet transformation (19-395 Hz). The resultant EMG waveforms (18 per subject) were submitted to intra-subject and inter-subject PCA. In all analyzed muscles, the shapes of the first and second principal component (PC-) vectors agreed well with the predicted waveforms. These two PC-vectors accounted for 50-60% of the overall variability, in both inter-subject and intra-subject analyses. It was also found that the shape of the first PC-vector was consistent between subjects, while higher-order PC-vectors differed between subjects. These results support the hypothesis that adaptation to, and preparation for, a variable heel-strike event are both major sources of EMG variability in walking. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Antidepressants Increase REM Sleep Muscle Tone in Patients with and without REM Sleep Behavior Disorder

    Science.gov (United States)

    McCarter, Stuart J.; St. Louis, Erik K.; Sandness, David J.; Arndt, Katlyn A.; Erickson, Maia K.; Tabatabai, Grace M.; Boeve, Bradley F.; Silber, Michael H.

    2015-01-01

    Study Objectives: REM sleep behavior disorder (RBD) is associated with antidepressant treatment, especially in younger patients; but quantitative REM sleep without atonia (RSWA) analyses of psychiatric RBD patients remain limited. We analyzed RSWA in adults receiving antidepressants, with and without RBD. Design: We comparatively analyzed visual, manual, and automated RSWA between RBD and control groups. RSWA metrics were compared between groups, and regression was used to explore associations with clinical variables. Setting: Tertiary-care sleep center. Participants: Participants included traditional RBD without antidepressant treatment (n = 30, 15 Parkinson disease [PD-RBD] and 15 idiopathic); psychiatric RBD receiving antidepressants (n = 30); and adults without RBD, including antidepressant-treated psychiatric (n = 30), untreated psychiatric (n = 15), and OSA (n = 60) controls. Interventions: N/A. Measurements and Results: RSWA was highest in traditional and psychiatric RBD, intermediate in treated psychiatric controls, and lowest in untreated psychiatric and OSA controls (P Erickson MK, Tabatabai GM, Boeve BF, Silber MH. Antidepressants Increase REM sleep muscle tone in patients with and without REM sleep behavior disorder. SLEEP 2015;38(6):907–917. PMID:25325487

  20. Eccentric resistance training increases and retains maximal strength, muscle endurance, and hypertrophy in trained men.

    Science.gov (United States)

    Coratella, Giuseppe; Schena, Federico

    2016-11-01

    The aim of the present study was to evaluate the effects of different resistance training protocols on muscle strength, endurance, and hypertrophy after training and detraining. Thirty-four resistance-trained males were randomized in concentric-only (CONC), eccentric-only (ECC), traditional concentric-eccentric (TRAD) bench press resistance training or control group. The training volume was equalized among the intervention groups. Bench press of 1-repetition maximum (1RM)/body mass, maximum number of repetitions (MNR), and chest circumference were evaluated at the baseline, after 6 weeks of training, and after 6 weeks of detraining. All intervention groups reported significant 1RM/body mass increases after training (CONC baseline: 1.04 ± 0.06, post-training: 1.12 ± 0.08, p training: 1.15 ± 0.05, p training: 1.11 ± 0.10, p training: 25 ± 3, and post-detraining: 25 ± 4, p training: 101.7 ± 2.2 cm and post-detraining: 100.7 ± 2.3 cm. p training can be recommended for counteracting the negative effects of detraining or forced physical inactivity.

  1. Glucose challenge increases circulating progenitor cells in Asian Indian male subjects with normal glucose tolerance which is compromised in subjects with pre-diabetes: A pilot study

    Directory of Open Access Journals (Sweden)

    Bairagi Soumi

    2011-01-01

    Full Text Available Abstract Background Haematopoietic stem cells undergo mobilization from bone marrow to blood in response to physiological stimuli such as ischemia and tissue injury. The aim of study was to determine the kinetics of circulating CD34+ and CD133+CD34+ progenitor cells in response to 75 g glucose load in subjects with normal and impaired glucose metabolism. Methods Asian Indian male subjects (n = 50 with no prior history of glucose imbalance were subjected to 2 hour oral glucose tolerance test (OGTT. 24 subjects had normal glucose tolerance (NGT, 17 subjects had impaired glucose tolerance (IGT and 9 had impaired fasting glucose (IFG. The IGT and IFG subjects were grouped together as pre-diabetes group (n = 26. Progenitor cell counts in peripheral circulation at fasting and 2 hour post glucose challenge were measured using direct two-color flow cytometry. Results The pre-diabetes group was more insulin resistant (p + cells (p = 0.003 and CD133+CD34+ (p = 0.019 cells was seen 2 hours post glucose challenge in the NGT group. This increase for both the cell types was attenuated in subjects with IGT. CD34+ cell counts in response to glucose challenge inversely correlated with neutrophil counts (ρ = -0.330, p = 0.019, while post load counts of CD133+CD34+ cells inversely correlated with serum creatinine (ρ = -0.312, p = 0.023. Conclusion There is a 2.5-fold increase in the circulating levels of haematopoietic stem cells in response to glucose challenge in healthy Asian Indian male subjects which is attenuated in subjects with pre-diabetes.

  2. Increased expression of atrogenes and TWEAK family members after severe burn injury in non-burned human skeletal muscle

    Science.gov (United States)

    Merritt, Edward K.; Thalacker-Mercer, Anna; Cross, James M.; Windham, Samuel T.; Thomas, Steven J.; Bamman, Marcas M.

    2012-01-01

    Severe burn induces rapid skeletal muscle proteolysis after the injury that persists for up to one year and results in skeletal muscle atrophy despite dietary and rehabilitative interventions. The purpose of this research was to determine acute changes in gene expression of skeletal muscle mass regulators post-burn injury. Biopsies were obtained from the vastus lateralis of a non-burned leg of eight burned subjects (6M, 2F: 34.8 ± 2.7 years: 29.9 ± 3.1% total body surface area burn) at 5.1 ± 1.1 days post-burn injury and from matched controls. mRNA expression of cytokines and receptors in the tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) families, and the ubiquitin proteasome E3 ligases, atrogin-1 and MuRF1, was determined. TNF receptor 1A was over 3.5 fold higher in burn. Expression of TNF-like weak inducer of apoptosis and its receptor were over 1.6 and 6.0-fold higher in burn. IL-6, IL-6 receptor, and glycoprotein 130, were elevated in burned subjects with IL-6 receptor over 13-fold higher. Suppressor of cytokine signaling-3 was also elevated in burn nearly 6-fold. Atrogin-1 and MuRF1, were more than 4- and 3-fold higher in burn. These results demonstrate for the first time that severe burn in humans has a remarkable impact on gene expression in skeletal muscle of a non-burned limb of genes that promote inflammation and proteolysis. Because these changes likely contribute to the acute skeletal muscle atrophy in areas not directly affected by the burn, in the future it will be important to determine the responsible systemic cues. PMID:23816995

  3. Influence of specific muscle training on pain, activity limitation and kinesiophobia in women with back pain post-partum--a 'single-subject research design'.

    Science.gov (United States)

    Gustafsson, Johanna; Nilsson-Wikmar, Lena

    2008-03-01

    Many women suffer from back pain and experience activity limitation post-partum. To our knowledge the physiological factors and physiotherapy related to back pain post-partum have received limited evaluation and the effectiveness of specific physiotherapeutic approaches to exercise should be tested. In addition, there has been limited research on kinesiophobia in women with back pain post-partum. The purpose of the current study was to test the influence of specific trunk muscle training on pain, activity limitation and kinesiophobia in 10 subjects with back pain post-partum. The treatment consisted of specific deep muscle training of the transversus abdominus and multifidus muscles. Pain was rated based on the visual analogue scale (VAS) and pain drawings. Activity limitation was recorded using the Disability Rating Index. Kinesiophobia was evaluated using the Swedish version of the Tampa Scale for Kinesiophobia. An A-B-A single-subject research design was used and a number of measurements were obtained during each phase. The analysis consisted of a visual inspection and a two standard deviation band test (2-SD). The visual analysis showed a trend towards reduced pain and activity limitation for all 10 subjects. The 2-SD test showed mixed results among all subjects. In addition, all subjects reported kinesiophobia before and after treatment. Individual specific deep muscle training of the transversus abdominus and multifidus muscles reduced pain and activity limitation in women with back pain post-partum. Further research is needed to determine more precisely how kinesiophobia affects women with back pain post-partum.

  4. Improved fatigue resistance in Gsα-deficient and aging mouse skeletal muscles due to adaptive increases in slow fibers

    Science.gov (United States)

    Feng, Han-Zhong; Chen, Min; Weinstein, Lee S.

    2011-01-01

    Genetically modified mice with deficiency of the G protein α-subunit (Gsα) in skeletal muscle showed metabolic abnormality with reduced glucose tolerance, low muscle mass, and low contractile force, along with a fast-to-slow-fiber-type switch (Chen M, Feng HZ, Gupta D, Kelleher J, Dickerson KE, Wang J, Hunt D, Jou W, Gavrilova O, Jin JP, Weinstein LS. Am J Physiol Cell Physiol 296: C930–C940, 2009). Here we investigated a hypothesis that the switching to more slow fibers is an adaptive response with specific benefit. The results showed that, corresponding to the switch of myosin isoforms, the thin-filament regulatory proteins troponin T and troponin I both switched to their slow isoforms in the atrophic soleus muscle of 3-mo-old Gsα-deficient mice. This fiber-type switch involving coordinated changes of both thick- and thin-myofilament proteins progressed in the Gsα-deficient soleus muscles of 18- to 24-mo-old mice, as reflected by the expression of solely slow isoforms of myosin and troponin. Compared with age-matched controls, Gsα-deficient soleus muscles with higher proportion of slow fibers exhibited slower contractile and relaxation kinetics and lower developed force, but significantly increased resistance to fatigue, followed by a better recovery. Gsα-deficient soleus muscles of neonatal and 3-wk-old mice did not show the increase in slow fibers. Therefore, the fast-to-slow-fiber-type switch in Gsα deficiency at older ages was likely an adaptive response. The benefit of higher fatigue resistance in adaption to metabolic deficiency and aging provides a mechanism to sustain skeletal muscle function in diabetic patients and elderly individuals. PMID: