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Sample records for high-intensity sub-maximal knee-extensor

  1. Muscular and pulmonary O2 uptake kinetics during moderate- and high-intensity sub-maximal knee-extensor exercise in humans

    DEFF Research Database (Denmark)

    Krustrup, Peter; Jones, Andrew M.; Wilkerson, Daryl P.;

    2009-01-01

    The purpose of this investigation was to determine the contribution of muscle O2 consumption (m O2) to pulmonary O2 uptake (p O2) during both low-intensity (LI) and high-intensity (HI) knee extension exercise, and during subsequent recovery, in humans. Seven healthy male subjects (age 20-25 years...

  2. High-intensity knee extensor training restores skeletal muscle function in COPD patients.

    Science.gov (United States)

    Brønstad, Eivind; Rognmo, Oivind; Tjonna, Arnt Erik; Dedichen, Hans Henrich; Kirkeby-Garstad, Idar; Håberg, Asta K; Bjørk Ingul, Charlotte; Wisløff, Ulrik; Steinshamn, Sigurd

    2012-11-01

    Improving reduced skeletal muscle function is important for optimising exercise tolerance and quality of life in chronic obstructive pulmonary disease (COPD) patients. By applying high-intensity training to a small muscle group, we hypothesised a normalisation of muscle function. Seven patients with COPD performed 6 weeks (3 days·week(-1)) of high-intensity interval aerobic knee extensor exercise training. Five age-matched healthy individuals served as a reference group. Muscle oxygen uptake and mitochondrial respiration of the vastus lateralis muscle were measured before and after the 6-week training programme. Initial peak work and maximal mitochondrial respiration were reduced in COPD patients and improved significantly after the training programme. Peak power and maximal mitochondrial respiration in vastus lateralis muscle increased to the level of the control subjects and were mainly mediated via improved complex I respiration. Furthermore, when normalised to citrate synthase activity, no difference in maximal respiration was found either after the intervention or compared to controls, suggesting normal functioning mitochondrial complexes. The present study shows that high-intensity training of a restricted muscle group is highly effective in restoring skeletal muscle function in COPD patients.

  3. Knee extensor strength and risk of structural, symptomatic and functional decline in knee osteoarthritis

    DEFF Research Database (Denmark)

    Culvenor, Adam G; Ruhdorfer, Anja; Juhl, Carsten

    2017-01-01

    . CONCLUSION: Meta-analysis showed that lower knee extensor strength is associated with an increased risk of symptomatic and functional deterioration, but not tibiofemoral JSN. The risk of patellofemoral deterioration in the presence of knee extensor strength deficits is inconclusive. This article is protected...

  4. Isokinetic and isometric muscle function of the knee extensors and flexors during simulated soccer activity: effect of exercise and dehydration.

    Science.gov (United States)

    Ali, Ajmol; Williams, Clyde

    2013-01-01

    This study investigated the influence of dehydration during soccer-type intermittent exercise on isokinetic and isometric muscle function. Eight soccer players performed two 90-min high-intensity intermittent shuttle-running trials without (NF) or with (FL) fluid ingestion (5 ml · kg(-1) before and 2 ml · kg(-1) every 15 min). Isokinetic and isometric strength and muscular power of knee flexors and knee extensors were measured pre-exercise, at half-time and post-exercise using isokinetic dynamometry. Sprint performance was monitored throughout the simulated-soccer exercise. Isokinetic knee strength was reduced at faster (3.13 rad · s(-1); P = 0.009) but not slower (1.05 rad · s(-1); P = 0.063) contraction speeds with exercise; however, there was no difference between FL and NF. Peak isometric strength of the knee extensors (P = 0.002) but not the knee flexors (P = 0.065) was significantly reduced with exercise with no difference between FL and NF. Average muscular power was reduced over time at both 1.05 rad · s(-1) (P = 0.01) and 3.14 rad · s(-1) (P = 0.033) but was not different between FL and NF. Mean 15-m sprint time increased with duration of exercise (P = 0.005) but was not different between FL and NF. In summary, fluid ingestion during 90 min of soccer-type exercise was unable to offset the reduction in isokinetic and isometric strength and muscular power of the knee extensors and flexors.

  5. Knee extensor muscle strength in middle-aged and older individuals undergoing arthroscopic partial meniscectomy

    DEFF Research Database (Denmark)

    Hall, Michelle; Juhl, Carsten B; Lund, Hans

    2015-01-01

    for a meniscal tear and used either a healthy control group or the contralateral leg to compare knee extensor muscle strength were included. Methodological quality was assessed using guidelines from the Centre for Reviews and Dissemination. RESULTS: Eleven studies, including predominately males were included (n......OBJECTIVE: People with meniscal tears are at high risk to develop or progress knee osteoarthritis. Knee extensor weakness is considered a risk factor for osteoarthritis and is often reported in these individuals. The purpose of this systematic review and meta-analysis was to investigate knee...... extensor strength in people undergoing an arthroscopic partial meniscectomy (APM). METHODS: Six databases (MEDLINE, CINAHL, SportDISCUS, EMBASE, PEDro and AMED) were searched up to June 22(nd) , 2014. Studies that measured knee extensor muscle strength in people aged 30 years and older undergoing APM...

  6. 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.

  7. Knee extensor strength is associated with pressure pain thresholds in adults with fibromyalgia.

    Directory of Open Access Journals (Sweden)

    W Michael Hooten

    Full Text Available OBJECTIVE: Individuals with fibromyalgia (FM have lower muscle strength and lower pressure pain thresholds (PPT. The primary aim of this study was to determine the associations between muscle strength and PPT in adults with FM to test the hypothesis that greater measures of muscle strength would be associated with greater values of PPT. Secondary aims included determining the effects of pain severity and the peak uptake of oxygen (VO2 on the associations between muscle strength and PPT. METHODS: Knee extensor and flexor strength (N = 69 was measured in the dominant leg using a dynamometer, and PPT was assessed using an electronic algometer. Pain severity was determined using the Multidimensional Pain Inventory, and peak VO2 uptake was quantified using an electronically braked cycle ergometer. RESULTS: Univariable linear regression analysis demonstrated a significant association between PPT (dependent variable and isometric knee extensor (P<.001, isokinetic (60°/s knee extensor (P = .002, and isokinetic (60°/s knee flexor strength (P = .043. In a multiple variable linear regression analysis adjusted for age, sex, pain severity, body mass index and peak VO2 uptake, a significant association was found between PPT and isometric knee extensor strength (P = .008. In a similar multiple variable analysis, a significant association was found between PPT and isokinetic knee extensor strength (P = .044. CONCLUSION: Greater measures of isometric and isokinetic knee extensor strength were significantly associated with greater values of PPT in both univariable and multiple variable linear regression models. TRIAL REGISTRATION: ClinicalTrials.gov NCT01253395.

  8. Soreness-related changes in three-dimensional running biomechanics following eccentric knee extensor exercise.

    Science.gov (United States)

    Paquette, Max R; Peel, Shelby A; Schilling, Brian K; Melcher, Dan A; Bloomer, Richard J

    2017-06-01

    Runners often experience delayed onset muscle soreness (DOMS), especially of the knee extensors, following prolonged running. Sagittal knee joint biomechanics are altered in the presence of knee extensor DOMS but it is unclear how muscle soreness affects lower limb biomechanics in other planes of motion. The purpose of this study was to assess the effects of knee extensor DOMS on three-dimensional (3D) lower limb biomechanics during running. Thirty-three healthy men (25.8 ± 6.8 years; 84.1 ± 9.2 kg; 1.77 ± 0.07 m) completed an isolated eccentric knee extensor damaging protocol to elicit DOMS. Biomechanics of over-ground running at a set speed of 3.35 m s(-1)±5% were measured before eccentric exercise (baseline) and, 24 h and 48 h following exercise in the presence of knee extensor DOMS. Knee flexion ROM was reduced at 48 h (P = 0.01; d = 0.26), and peak knee extensor moment was reduced at 24 h (P = 0.001; d = 0.49) and 48 h (P biomechanics were unaffected by the presence of DOMS (P > 0.05). Peak positive ankle and knee joint powers and, peak negative knee joint power were all reduced from baseline to 24 h and 48 h (P biomechanics during running.

  9. Effect of Knee Extensor Strength on Incident Radiographic and Symptomatic Knee Osteoarthritis in Individuals with Meniscal Pathology

    DEFF Research Database (Denmark)

    Thorlund, Jonas B; Felson, David T; Segal, Neil A

    2016-01-01

    OBJECTIVE: High knee extensor strength may be important to protect against development of knee osteoarthritis (OA) in populations at elevated risk, such as individuals with meniscal pathology. We investigated the extent to which high knee extensor muscle strength was associated with a decreased r...

  10. The effects of imagery on fast isometric knee extensor torque development

    NARCIS (Netherlands)

    Ruiter, de C.J.; Hutter, R.I.; Icke, C; Groen, B; Gemmink, A; Smilde, H; Haan, de A.

    2012-01-01

    0.05) to significant increases of knee extensor rectified surface EMG at torque onset (EMG40). In conclusion, only physical training led to a knee angle specific increase of contractile impulse that was significantly different from placebo and controls and that was related to improved onset of neuro

  11. Metabolic demand and muscle damage induced by eccentric cycling of knee extensor and flexor muscles.

    Science.gov (United States)

    Peñailillo, Luis; Guzmán, Nicolás; Cangas, José; Reyes, Alvaro; Zbinden-Foncea, Hermann

    2017-03-01

    The aim of this study was to examine the metabolic demand and extent of muscle damage of eccentric cycling targeting knee flexor (FLEX) and knee extensor (EXT) muscles. Eight sedentary men (23.3 ± 0.7 y) underwent two eccentric cycling sessions (EXT and FLEX) of 30 min each, at 60% of the maximum power output. Oxygen consumption (VO2), heart rate (HR) and rated perceived exertion (RPE) were measured during cycling. Countermovement and squat jumps (CMJ and SJ), muscle flexibility, muscle soreness and pain pressure threshold (PPT) of knee extensor and flexor muscles were measured before, immediately after and 1-4 days after cycling. FLEX showed greater VO2 (+23%), HR (+14%) and RPE (+18%) than EXT. CMJ and SJ performance decreased similarly after cycling. Muscle soreness increased more after EXT than FLEX and PPT decreased in knee extensor muscles after EXT and decreased in knee flexor muscles after FLEX. Greater loss of muscle flexibility in knee flexor muscles after FLEX was observed. Eccentric cycling of knee flexor muscles is metabolically more demanding than that of knee extensors, however muscle damage induced is similar. Knee flexors experienced greater loss of muscle flexibility possibly due to increased muscle stiffness following eccentric contractions.

  12. The Effect of Visual Impairment on the Strength of Children's Hip and Knee Extensors.

    Science.gov (United States)

    Wyatt, L.; Ng, G. Y.

    1997-01-01

    A test of 32 children's hip and knee extensors found that children born blind or with low vision are at risk of developing weak lower-limb extensors, with congenitally blind children at greatest risk. After correcting for lean body weight, the differences between sighted children and those with low vision were insignificant. Results support the…

  13. Speed-related spinal excitation from ankle dorsiflexors to knee extensors during human walking

    DEFF Research Database (Denmark)

    Iglesias, Caroline; Nielsen, Jens Bo; Marchand-Pauvert, Véronique

    2008-01-01

    Automatic adjustments of muscle activity throughout the body are required for the maintenance of balance during human walking. One mechanism that is likely to contribute to this control is the heteronymous spinal excitation between human ankle dorsiflexors and knee extensors (CPQ-reflex). Here, we...

  14. Knee extensor muscle weakness is a risk factor for development of knee osteoarthritis

    DEFF Research Database (Denmark)

    Oiestad, B E; Juhl, C B; Eitzen, I

    2015-01-01

    The objective of this study was to perform a systematic review and meta-analysis on the association between knee extensor muscle weakness and the risk of developing knee osteoarthritis. A systematic review and meta-analysis was conducted with literature searches in Medline, SPORTDiscus, EMBASE, C...

  15. Angle- and gender-specific quadriceps femoris muscle recruitment and knee extensor torque.

    Science.gov (United States)

    Pincivero, Danny M; Salfetnikov, Yuliya; Campy, Robert M; Coelho, Alan J

    2004-11-01

    The objectives were to examine knee angle-, and gender-specific knee extensor torque output and quadriceps femoris (QF) muscle recruitment during maximal effort, voluntary contractions. Fourteen young adult men and 15 young adult women performed three isometric maximal voluntary contractions (MVC), in a random order, with the knee at 0 degrees (terminal extension), 10 degrees, 30 degrees, 50 degrees, 70 degrees, and 90 degrees flexion. Knee extensor peak torque (PT), and average torque (AT) were expressed in absolute (N m), relative (N m kg(-1)) and allometric-modeled (N m kg(-n)) units. Vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) muscle EMG signals were full-wave rectified and integrated over the middle 3 s of each contraction, averaged over the three trials at each knee angle, and normalized to the activity recorded at 0 degrees. Muscle recruitment efficiency was calculated as the ratio of the normalized EMG of each muscle to the allometric-modeled average torque (normalized to the values at 0 degrees flexion), and expressed as a percent. Men generated significantly greater knee extensor PT and AT than women in absolute, relative and allometric-modeled units. Absolute and relative PT and AT were significantly highest at 70 degrees, while allometric-modeled values were observed to increase significantly across knee joint angles 10-90 degrees. VM EMG was significantly greater than the VL and RF muscles across all angles, and followed a similar pattern to absolute knee extensor torque. Recruitment efficiency improved across knee joint angles 10-90 degrees and was highest for the VL muscle. VM recruitment efficiency improved more than the VL and RF muscles across 70-90 degrees flexion. The findings demonstrate angle-, and gender-specific responses of knee extensor torque to maximal-effort contractions, while superficial QF muscle recruitment was most efficient at 90 degrees, and less dependent on gender.

  16. Radiographic analysis of factors predisposing toward tendon tears in the knee extensor mechanism

    Directory of Open Access Journals (Sweden)

    Rodrigo Pires e Albuquerque

    2014-08-01

    Full Text Available Objectives:To review radiographs of patients who suffered tendon tears of the knee extensor apparatus and observe alterations that might be factors predisposing toward this type of injury.Methods:We retrospectively analyzed 60 cases of injury to the knee extensor mechanism that were treated surgically at the Miguel Couto Municipal Hospital between March 2004 and March 2011. Four patients were excluded due to poor quality of the examination.Results:Of the 56 patients evaluated, 23 were considered to be normal and 33 presented radiographic alterations. Among these, eight (24.3% presented suprapatellar osteophytes alone; seven (21.2%, infrapatellar calcification; seven (21.2%, suprapatellar calcification; six (18.2%, supra- and infrapatellar osteophytes; and five (15.1%, infrapatellar osteophytes alone.Conclusion:Radiographic alterations were frequently observed in patients with extensor mechanism tears.

  17. Enhanced spinal excitation from ankle flexors to knee extensors during walking in stroke patients

    DEFF Research Database (Denmark)

    Achache, V.; Mazevet, D.; Iglesias, C.

    2010-01-01

    OBJECTIVES: It is still unclear to what an extent altered reflex activity contributes to gait deficit following stroke. Spinal group I and group II excitations from ankle dorsiflexors to knee extensors were investigated during post-stroke walking. METHODS: Electrical stimulation was applied...... to the common peroneal nerve (CPN) in the early stance, and the short-latency biphasic excitation in Quadriceps motoneurones was evaluated from the Vastus Lateralis (VL) rectified and averaged (N=50) EMG activity in 14 stroke patients walking at 0.6-1.6 km/h, and 14 control subjects walking at 3.2-4.8 and at 1......: The spinal, presumed group II, excitation from ankle dorsiflexors to knee extensors is particularly enhanced during post-stroke walking probably due to plastic adaptations in the descending control. SIGNIFICANCE: This adaptation may help to stabilize the knee in early stance when the patients have recover...

  18. Effects of strength training and detraining on knee extensor strength, muscle volume and muscle quality in elderly women

    OpenAIRE

    Correa, Cleiton Silva; Baroni, Bruno Manfredini; Radaelli, Régis; Lanferdini,Fábio Juner; Cunha, Giovani dos Santos; Reischak-Oliveira, Álvaro; Vaz, Marco Aurélio; Pinto, Ronei Silveira

    2012-01-01

    Strength training seems to be an interesting approach to counteract decreases that affect knee extensor strength, muscle mass and muscle quality (force per unit of muscle mass) associated with ageing. However, there is no consensus regarding the changes in muscle mass and their contribution to strength during periods of training and detraining in the elderly. Therefore, this study aimed at verifying the behaviour of knee extensor muscle strength, muscle volume and muscle quality in elderly wo...

  19. Effect of low-level laser therapy on muscle adaptation to knee extensor eccentric training.

    Science.gov (United States)

    Baroni, Bruno Manfredini; Rodrigues, Rodrigo; Freire, Bruno Bolla; Franke, Rodrigo de Azevedo; Geremia, Jeam Marcel; Vaz, Marco Aurélio

    2015-03-01

    Eccentric training has been popularized for physical conditioning and prevention/rehabilitation of musculoskeletal disorders, especially due to the expressive responses in terms of muscular strength gain. In view of evidence that low-level laser therapy (LLLT) is able to increase exercise performance and accelerate post-exercise recovery, the aim of this study was to verify the effect of LLLT on hypertrophy and strengthening of knee extensor muscles submitted to eccentric training. Thirty healthy male subjects were randomized into three groups: Control Group (CG), Training Group (TG) and Training + LLLT Group (TLG). CG received no intervention, while TG and TLG were engaged on an 8-week knee extensor isokinetic eccentric training program. Only subjects from TLG were treated with LLLT (wavelength = 810 nm; power output = 200 mW; total dosage = 240 J) before each training session. Knee extensor muscle thickness and peak torque were assessed through ultrasonography and isokinetic dynamometry, respectively. CG presented no changes in any variable throughout the study, while eccentric training led to significant increases in muscle thickness and peak torque in TG and TLG. Subjects from TLG reached significantly higher percent changes compared to subjects from TG for sum of muscles' thicknesses (15.4 vs. 9.4%), isometric peak torque (20.5 vs. 13.7%), and eccentric peak torque (32.2 vs. 20.0%). LLLT applied before eccentric training sessions seems to improve the hypertrophic response and muscular strength gain in healthy subjects.

  20. Acute Effects of Kinesio Taping on Knee Extensor Peak Torque and Stretch Reflex in Healthy Adults

    Science.gov (United States)

    Yeung, Simon S.; Yeung, Ella W.

    2016-01-01

    Abstract Kinesio Tex tape (KT) is used to prevent and treat sports-related injuries and to enhance muscle performance. It has been proposed that the direction of taping may either facilitate or inhibit the muscle by having different effects on cutaneous receptors that modulate excitability of the motor neurons. This study had 2 goals. First, we wished to determine if KT application affects muscle performance and if the method of application facilitates or inhibits muscle performance. This was assessed by measuring isokinetic knee extension peak torque in the knee extensor. Second, we assessed neurological effects of taping on the excitability of the motor neurons by measuring the reflex latency and action potential by electromyography (EMG) in the patellar reflex. The study was a single-blind, placebo-controlled crossover trial with 28 healthy volunteers with no history of knee injuries. Participants received facilitative KT treatment, inhibitory KT treatment, or Hypafix taping of the knee extensor. There were significant differences in the peak torque between 3 treatments (F(2,54) = 4.873, P < 0.01). Post hoc analysis revealed that facilitative KT treatment resulted in higher knee extensor peak torque performance than inhibitory KT treatment (P = 0.036, effect size 0.26). There were, however, no significant differences in the reflex latency (F(2,54) = 2.84, P = 0.067) nor in the EMG values (F(2,54) = 0.18, P = 0.837) in the patellar reflex between the 3 taping applications. The findings suggest that the direction of KT application over the muscle has specific effects on muscle performance. Given the magnitude of effect is small, interpretation of clinical significance should be considered with caution. The underlying mechanism warrants further investigation. PMID:26825916

  1. Effect of Preactivation on Torque Enhancement by the Stretch-Shortening Cycle in Knee Extensors.

    Science.gov (United States)

    Fukutani, Atsuki; Misaki, Jun; Isaka, Tadao

    2016-01-01

    The stretch-shortening cycle is one of the most interesting topics in the field of sport sciences, because the performance of human movement is enhanced by the stretch-shortening cycle (eccentric contraction). The purpose of the present study was to examine whether the influence of preactivation on the torque enhancement by stretch-shortening cycle in knee extensors. Twelve men participated in this study. The following three conditions were conducted for knee extensors: (1) concentric contraction without preactivation (CON), (2) concentric contraction with eccentric preactivation (ECC), and (3) concentric contraction with isometric preactivation (ISO). Muscle contractions were evoked by electrical stimulation to discard the influence of neural activity. The range of motion of the knee joint was set from 80 to 140 degrees (full extension = 180 degrees). Angular velocities of the concentric and eccentric contractions were set at 180 and 90 degrees/s, respectively. In the concentric contraction phase, joint torques were recorded at 85, 95, and 105 degrees, and they were compared among the three conditions. In the early phase (85 degrees) of concentric contraction, the joint torque was larger in the ECC and ISO conditions than in the CON condition. However, these clear differences disappeared in the later phase (105 degrees) of concentric contraction. The results showed that joint torque was clearly different among the three conditions in the early phase whereas this difference disappeared in the later phase. Thus, preactivation, which is prominent in the early phase of contractions, plays an important role in torque enhancement by the stretch-shortening cycle in knee extensors.

  2. Effects of Neuromuscular Electrical Stimulation and Resistance Training on Knee Extensor/Flexor Muscles.

    Science.gov (United States)

    Pantović, Milan; Popović, Boris; Madić, Dejan; Obradović, Jelena

    2015-07-01

    Neuromuscular electrical stimulation (NMES) has recently drawn a lot of attention as means for strengthening of voluntary muscle contraction both in sport and rehabilitation. NMES training increases maximal voluntary contraction (MVC) force output through neural adaptations. On the other hand, positive effects of resistance training (RT) on muscle strength are well known. The aim of this study was to investigate effects of a 5-week program of NMES compared to RT program of same duration. Sample of 15 students' of faculty of sport and physical education (age 22 ± 2) were randomized in two groups: NMES (N = 7) and RT (N = 8). NMES group performed NMES superimposed over voluntary muscle contraction, RT group performed resistance training with submaximal loads. Subjects were evaluated for knee isokinetic dynamometry on both sides (60° and 180° s). After intervention no significant difference between groups were observed in isokinetic dynamometry (p = 0.177). However, applying pair sample t test within each group revealed that peak torque increased in NMES-group (p = 0.002 for right knee extensors muscles, p = 0.003 for left, respectively, at 60° and p = 0.004 for left knee extensors muscles, at angular velocity 180°). In RT group (p = 0.033 for right knee extensors muscles, p = 0.029 for right knee flexor muscles, at angular velocity 60°). Our results indicate that NMES has equal potential if not in some way better than classical RT having in mind that overload on locomotor apparatus during NMES is minimal and force of muscle contraction is equal on both sides, for enhancement of knee muscles concentric peak torque.

  3. Acute Effects of Kinesio Taping on Knee Extensor Peak Torque and Stretch Reflex in Healthy Adults.

    Science.gov (United States)

    Yeung, Simon S; Yeung, Ella W

    2016-01-01

    Kinesio Tex tape (KT) is used to prevent and treat sports-related injuries and to enhance muscle performance. It has been proposed that the direction of taping may either facilitate or inhibit the muscle by having different effects on cutaneous receptors that modulate excitability of the motor neurons. This study had 2 goals. First, we wished to determine if KT application affects muscle performance and if the method of application facilitates or inhibits muscle performance. This was assessed by measuring isokinetic knee extension peak torque in the knee extensor. Second, we assessed neurological effects of taping on the excitability of the motor neurons by measuring the reflex latency and action potential by electromyography (EMG) in the patellar reflex. The study was a single-blind, placebo-controlled crossover trial with 28 healthy volunteers with no history of knee injuries. Participants received facilitative KT treatment, inhibitory KT treatment, or Hypafix taping of the knee extensor. There were significant differences in the peak torque between 3 treatments (F(2,54) = 4.873, P < 0.01). Post hoc analysis revealed that facilitative KT treatment resulted in higher knee extensor peak torque performance than inhibitory KT treatment (P = 0.036, effect size 0.26). There were, however, no significant differences in the reflex latency (F(2,54) = 2.84, P = 0.067) nor in the EMG values (F(2,54) = 0.18, P = 0.837) in the patellar reflex between the 3 taping applications. The findings suggest that the direction of KT application over the muscle has specific effects on muscle performance. Given the magnitude of effect is small, interpretation of clinical significance should be considered with caution. The underlying mechanism warrants further investigation.

  4. Effect of Preactivation on Torque Enhancement by the Stretch-Shortening Cycle in Knee Extensors.

    Directory of Open Access Journals (Sweden)

    Atsuki Fukutani

    Full Text Available The stretch-shortening cycle is one of the most interesting topics in the field of sport sciences, because the performance of human movement is enhanced by the stretch-shortening cycle (eccentric contraction. The purpose of the present study was to examine whether the influence of preactivation on the torque enhancement by stretch-shortening cycle in knee extensors. Twelve men participated in this study. The following three conditions were conducted for knee extensors: (1 concentric contraction without preactivation (CON, (2 concentric contraction with eccentric preactivation (ECC, and (3 concentric contraction with isometric preactivation (ISO. Muscle contractions were evoked by electrical stimulation to discard the influence of neural activity. The range of motion of the knee joint was set from 80 to 140 degrees (full extension = 180 degrees. Angular velocities of the concentric and eccentric contractions were set at 180 and 90 degrees/s, respectively. In the concentric contraction phase, joint torques were recorded at 85, 95, and 105 degrees, and they were compared among the three conditions. In the early phase (85 degrees of concentric contraction, the joint torque was larger in the ECC and ISO conditions than in the CON condition. However, these clear differences disappeared in the later phase (105 degrees of concentric contraction. The results showed that joint torque was clearly different among the three conditions in the early phase whereas this difference disappeared in the later phase. Thus, preactivation, which is prominent in the early phase of contractions, plays an important role in torque enhancement by the stretch-shortening cycle in knee extensors.

  5. Modulation of recurrent inhibition from knee extensors to ankle motoneurones during human walking

    DEFF Research Database (Denmark)

    Lamy, Jean-Charles; Iglesias, Caroline; Lackmy, Alexandra

    2008-01-01

    The neural control for muscle coordination during human locomotion involves spinal and supraspinal networks, but little is known about the exact mechanisms implicated. The present study focused on modulation of heteronymous recurrent inhibition from knee extensors to ankle motoneurones at different...... times in the gait cycle, when quadriceps (Quad) muscle activity overlaps that in tibialis anterior (TA) and soleus (Sol). The effects of femoral nerve stimulation on ankle motoneurones were investigated during treadmill walking and during tonic co-contraction of Quad and TA/Sol while standing. Recurrent...

  6. Reliability of contractile properties of the knee extensor muscles in individuals with post-polio syndrome.

    Directory of Open Access Journals (Sweden)

    Eric L Voorn

    Full Text Available To assess the reliability of contractile properties of the knee extensor muscles in 23 individuals with post-polio syndrome (PPS and 18 age-matched healthy individuals.Contractile properties of the knee extensors were assessed from repeated electrically evoked contractions on 2 separate days, with the use of a fixed dynamometer. Reliability was determined for fatigue resistance, rate of torque development (MRTD, and early and late relaxation time (RT50 and RT25, using the intraclass correlation coefficient (ICC and standard error of measurement (SEM, expressed as % of the mean.In both groups, reliability for fatigue resistance was good, with high ICCs (>0.90 and small SEM values (PPS: 7.1%, healthy individuals: 7.0%. Reliability for contractile speed indices varied, with the best values found for RT50 (ICCs>0.82, SEM values <2.8%. We found no systematic differences between test and retest occasions, except for RT50 in healthy subjects (p = 0.016.In PPS and healthy individuals, the reliability of fatigue resistance, as obtained from electrically evoked contractions is high. The reliability of contractile speed is only moderate, except for RT50 in PPS, demonstrating high reliability.This was the first study to examine the reliability of electrically evoked contractile properties in individuals with PPS. Our results demonstrate its potential to study mechanisms underlying muscle fatigue in PPS and to evaluate changes in contractile properties over time in response to interventions or from natural course.

  7. Knee extensor fatigue threshold is related to whole-body VO2max.

    Science.gov (United States)

    de Ruiter, Cornelis J; Maas, Ellen A; Wesseling, Mariska G H; de Haan, Arnold

    2012-07-01

    Above a given exercise intensity, rapid muscle fatigue will occur. We explored the possibility of assessing torque threshold for peripheral fatigue during single-legged repetitive isometric knee extensor exercise. We hypothesized this fatigue threshold to be related to the general aerobic fitness level and the so-called "critical torque" (CT) established with a recently validated 5-min all-out test. Seventeen healthy men (VO(2max) = 44.7-69.6 mL·kg(-1)·min(-1)) performed six submaximal (20%-55% maximal voluntary contraction [MVC]) 5-min bouts of 60 repetitive contractions (3-s on, 2-s off). Torque was changed between bouts in steps of 5% MVC to estimate the highest intensity (fatigue threshold) at which average changes in rsEMG, EMG median power frequency, and tissue deoxygenation (near-infrared spectroscopy) of the three superficial knee extensor muscles were still test torque representing CT. Fatigue threshold (40.0% ± 8.1% MVC) was related (r(2) = 0.57, P test may be used to evaluate changes in endurance capacity of single muscle groups, without the necessity for all-out testing, which could be problematic with frail subjects.

  8. Reliability of knee extensor and flexor muscle strength measurements in persons with late effects of polio.

    Science.gov (United States)

    Flansbjer, Ulla-Britt; Lexell, Jan

    2010-06-01

    To assess the reliability of knee extensor and flexor muscle strength measurements in persons with late effects of polio. A test-retest reliability study. Thirty men and women (mean age 63 (standard deviation 6.4) years) with verified late effects of polio. Knee extensor and flexor muscle strength in both lower limbs were measured twice 7 days apart using a Biodex dynamometer (isokinetic concentric contractions at 60 degrees /sec and isometric contractions with knee flexion angle 90 degrees) and a Leg Extension/Curl Rehab exercise machine with pneumatic resistance (HUR) (isotonic contractions). Reliability was assessed with the intraclass correlation coefficient (ICC1,1), the mean difference between the test sessions (d) together with the 95% confidence intervals for d, the standard error of measurement (SEM and SEM%), the smallest real difference (SRD and SRD%) and Bland-Altman graphs. Test-retest agreements were high, (ICC1,1 0.93-0.99) and measurement errors generally small. The SEM% was 4-14% and the SRD% 11-39%, with the highest values for the isokinetic measurements. Knee muscle strength can be measured reliably and can be used to detect real changes after an intervention for a group of persons with late effects of polio, whereas the values may be too high for single individuals or to detect smaller short-term changes over time for a group of individuals.

  9. Voluntary activation of human knee extensors measured using transcranial magnetic stimulation.

    Science.gov (United States)

    Goodall, S; Romer, L M; Ross, E Z

    2009-09-01

    The aim of this study was to determine the applicability and reliability of a transcranial magnetic stimulation twitch interpolation technique for measuring voluntary activation of a lower limb muscle group. Cortical voluntary activation of the knee extensors was determined in nine healthy men on two separate visits by measuring superimposed twitch torques evoked by transcranial magnetic stimulation during isometric knee extensions of varying intensity. Superimposed twitch amplitude decreased linearly with increasing voluntary torque between 50 and 100% of mean maximal torque, allowing estimation of resting twitch amplitude and subsequent calculation of voluntary activation. There were no systematic differences for maximal voluntary activation within day (mean +/- s.d. 90.9 +/- 6.2 versus 90.7 +/- 5.9%; P = 0.98) or between days (90.8 +/- 6.0 versus 91.2 +/- 5.7%; P = 0.92). Systematic bias and random error components of the 95% limits of agreement were 0.23 and 9.3% within day versus 0.38 and 7.5% between days. Voluntary activation was also determined immediately after a 2 min maximal voluntary isometric contraction; in four of these subjects, voluntary activation was determined 30 min after the sustained contraction. Immediately after the sustained isometric contraction, maximal voluntary activation was reduced from 91.2 +/- 5.7 to 74.2 +/- 12.0% (P knee extensors.

  10. Strength improvement of knee extensor muscles in patients with chronic heart failure by neuromuscular electrical stimulation.

    Science.gov (United States)

    Quittan, M; Sochor, A; Wiesinger, G F; Kollmitzer, J; Sturm, B; Pacher, R; Mayr, W

    1999-05-01

    Patients with severe chronic heart failure (CHF) suffer from marked weakness of skeletal muscles. Neuromuscular electrical stimulation (NMES) proved to be an alternative to active strength training. The objective of this study was to test the feasibility and effectiveness of NMES in patients with chronic heart failure. Seven patients (56.0 +/- 5.0 years, CHF for 20 +/- 4 months, left ventricular ejection fraction 20.1 +/- 10.0%) finished an 8 week course of NMES of the knee extensor muscles. The stimulator delivered biphasic, symmetric, constant voltage impulses of 0.7 ms pulse width with a frequency of 50 Hz, 2 s on and 6 s off. No adverse effects occurred. After the stimulation period, the isokinetic peak torque of the knee extensor muscles increased by 13% from 101.0 +/- 8.7 Nm to 113.5 +/- 7.2 Nm (p = 0.004). The maximal isometric strength increased by 20% from 294.3 +/- 19.6 N to 354.14 +/- 15.7 N (p = 0.04). This increased muscle strength could be maintained in a 20 min fatigue test indicating decreased muscle fatigue. These results demonstrate that NMES of skeletal muscles in patients with severe chronic heart failure is a promising method for strength training in this group of patients.

  11. Strength asymmetry of the knee extensors and physical activity in middle-aged women

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    Michal Lehnert

    2014-09-01

    Full Text Available Background: Differences between muscle strength and power of lower limbs is one of the factors associated with falls in the elderly population. Muscle strength asymmetry of lower limbs increases with age. Objective: The aim of the study is to assess differences in the volume and intensity of physical activity (PA in the subgroups of women being at higher and lower risk of falls (with and without strength asymmetry of the knee extensors of dominant and non-dominant lower limb. Methods: Data from 42 women (age 56.3 ± 4.4 years; weight 76.5 ± 16.1 kg; body height 164.3 ± 5.2 cm; body mass index 28.1 ± 5.3 kg . m-2 were used for the purpose of the presented analysis. Furthermore the sample was divided into subgroups with lower and higher strength asymmetry of quadriceps muscle (as a criterion the asymmetry greater than 15% was chosen. Absolute concentric peak torque of the knee extensors was evaluated by an isokinetic dynamometer IsoMed 2000 in a sitting position at angular velocity of 180° . s-1. PA was monitored using Yamax SW-700 pedometers throughout 7 consecutive days and using the Czech version of standardized International Physical Activity Questionnaire. Results: Statistically significant differences between groups with lower and higher strength asymmetry were found in the amount of self-reported vigorous PA (p = .04; d = 0.6 only. Differences between the observed groups were not significant in self-reported moderate PA and walking. There were also no significant differences in the daily numbers of steps measured objectively. Conclusions: The results of the study indicate that from the point of view of strength asymmetry of knee extensors as a factor associated with falls in middle-aged women, intensity of PA could be an important characteristic of PA. This suggestion should be taken into account in habitual PA and training programs in middle-aged population.

  12. Sit-to-Stand Movement in Children with Hemiplegic Cerebral Palsy: Relationship with Knee Extensor Torque and Social Participation

    Science.gov (United States)

    dos Santos, Adriana Neves; Pavao, Silvia Leticia; Santiago, Paulo Roberto Pereira; Salvini, Tania de Fatima; Rocha, Nelci Adriana Cicuto Ferreira

    2013-01-01

    This study aimed to investigate the relationship between sit-to-stand (STS) movement, knee extensor torque and social participation in children with cerebral palsy (CP). Seven spastic hemiplegic CP patients (8.0 plus or minus 2.2 years), classified by the Gross Motor Function Classification System as I and II, and 18 typical children (8.4 plus or…

  13. Knee extensor strength and body weight in adolescent men and the risk of knee osteoarthritis by middle age

    DEFF Research Database (Denmark)

    Turkiewicz, Aleksandra; Timpka, Simon; Thorlund, Jonas Bloch

    2017-01-01

    OBJECTIVES: To assess the extent to which knee extensor strength and weight in adolescence are associated with knee osteoarthritis (OA) by middle age. METHODS: We studied a cohort of 40 121 men who at age 18 years in 1969/1970 underwent mandatory conscription in Sweden. We retrieved data on isome...

  14. Suspected feigned knee extensor weakness: usefulness of 3D gait analysis. Case report.

    Science.gov (United States)

    Chaler, Joaquim; Müller, Bertram; Maiques, Anna; Pujol, Eduard

    2010-07-01

    The purpose of the present case report is to show the potential for use of 3D gait analysis as an assessment method of feigned muscle weakness. We describe a patient complaining of right leg pain and weakness. Physical examination showed severe quadriceps muscle weakness in a highly abnormal gait pattern context. Conventional diagnostic workup did not show any relevant findings. Three-dimensional (3D) gait analysis was performed with a 3D motion capture system. Joint angles, internal moments and powers were computed from the motion data. Lower leg muscle surface-electromyography was also performed. During the late stance phase, flexor moment and negative power peaks (indicating eccentric knee extensor activity) were generated in the knee, together with relevant Rectus femoris activity. All findings were highly inconsistent with true quadriceps weakness and gave objective ground to suspect insincerity of patient complaints. 3D gait analysis might be a valuable clinical assessment tool in suspected feigned lower limb muscle weakness.

  15. Effects of knee extensor muscle strength on the incidence of osteopenia and osteoporosis after 6 years.

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    Matsui, Yasumoto; Takemura, Marie; Harada, Atsushi; Ando, Fujiko; Shimokata, Hiroshi

    2014-09-01

    The association of knee extensor muscle strength with bone mineral density (BMD) has been reported in cross-sectional epidemiological studies, but it remains unclear whether or not this is the case with longitudinal change. Thus, we investigated whether or not the knee extension strength can predict the incidence of osteopenia or osteoporosis after 6 years, then compared the difference between sexes. Subjects were 1255 community-dwelling Japanese men and menopaused women, aged 40-81 years. BMD of lumbar spine and femoral neck was assessed by dual-energy X-ray absorptiometry twice at 6-year intervals. Subjects were divided into three groups, normal, osteopenia, and osteoporosis, depending on their young adult mean BMD % value. In the cross-sectional analysis the correlations between the knee extension strength and BMD of the two regions were examined, using Pearson's correlation coefficient. Longitudinal analyses were then conducted to determine the odds ratio, controlled for age and BMI, given that those who were normal in the initial stage developed osteopenia or osteoporosis after 6 years, for every 1 SD decrease in knee extension strength, as well as those who first had normal or osteopenia and then developed osteoporosis. Cross-sectional analysis showed a statistically significant relation between knee extensor muscle strength and BMD at both the lumbar spine (p = 0.02) and the femoral neck (p muscle strength on the loss of femoral neck BMD from normal to osteopenia or osteoporosis both in men (OR 1.84, 95 % CI 1.36-2.48, p strength to maintain the bone health of the proximal femur and spine in aging particularly in men.

  16. β-alanine supplementation improves isometric endurance of the knee extensor muscles

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    Sale Craig

    2012-06-01

    Full Text Available Abstract Background We examined the effect of four weeks of β-alanine supplementation on isometric endurance of the knee extensors at 45% maximal voluntary isometric contraction (MVIC. Methods Thirteen males (age 23 ± 6 y; height 1.80 ± 0.05 m; body mass 81.0 ± 10.5 kg, matched for pre-supplementation isometric endurance, were allocated to either a placebo (n = 6 or β-alanine (n = 7; 6.4 g·d-1 over 4 weeks supplementation group. Participants completed an isometric knee extension test (IKET to fatigue, at an intensity of 45% MVIC, before and after supplementation. In addition, two habituation tests were completed in the week prior to the pre-supplementation test and a further practice test was completed in the week prior to the post-supplementation test. MVIC force, IKET hold-time, and impulse generated were recorded. Results IKET hold-time increased by 9.7 ± 9.4 s (13.2% and impulse by 3.7 ± 1.3 kN·s-1 (13.9% following β-alanine supplementation. These changes were significantly greater than those in the placebo group (IKET: t(11 = 2.9, p ≤0.05; impulse: t(11 = 3.1, p ≤ 0.05. There were no significant changes in MVIC force in either group. Conclusion Four weeks of β-alanine supplementation at 6.4 g·d-1 improved endurance capacity of the knee extensors at 45% MVIC, which most likely results from improved pH regulation within the muscle cell as a result of elevated muscle carnosine levels.

  17. Validity and inter-day reliability of a free-oscillation test to measure knee extensor and knee flexor musculo-articular stiffness.

    Science.gov (United States)

    Ditroilo, Massimiliano; Watsford, Mark; De Vito, Giuseppe

    2011-06-01

    The purpose of this study was to assess the validity and inter-day reliability of musculo-articular stiffness (MAS) in the knee-extensor (KE) and knee-flexor (KF) muscle groups, measured with a free-oscillation technique. Fourteen participants were measured, on two occasions, for KE and KF maximal isometric voluntary contraction, rate of torque development (RTD) and electromechanical delay (EMD), along with MAS using multiple sub-maximal loads relative to the individual's maximal voluntary contraction (MAS(%MVC)). Furthermore, 18 participants were tested for MAS using one fixed assessment load for each muscle group (MAS(FL)) during a separate series of tests on three occasions. MAS(%MVC) was significantly increased as load increased both in KE and in KF (p<0.01) fitting a curvilinear relationship as depicted in similar studies. Validity was demonstrated relating MAS(%MVC) to RTD (r=0.51-0.71, p<0.05) and to EMD (r=-0.56 to -0.67, p<0.05). While MAS(%MVC) reliability (ICC=0.62-0.89; CV=8.1-13.1%) was questionable to acceptable, MAS(FL) exhibited good to excellent reliability (ICC=0.81-0.94; CV=3.7-6.5%). No significant systematic bias was detected for any of the variables considered. The assessment of KE and KF MAS using the free-oscillation technique appears to be valid and reliable, with the use of MAS(FL) yielding higher reliability than the use of MAS(%MVC). Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. The Artificial Gravity Bed Rest Pilot Project: Effects on Knee Extensor and Plantar Flexor Muscle Groups

    Science.gov (United States)

    Caiozzo, V. J.; Haddad, F.; Lee, S.; Baker, M.; Baldwin, K. M.

    2007-01-01

    The goal of this project was to examine the effects of artificial gravity (2.5 g) on skeletal muscle strength and key anabolic/catabolic markers known to regulate muscle mass. Two groups of subjects were selected for study: 1) a 21 day-bed rest (BR) control (C) group (N=7); and 2) an AG group (N=8), which was exposed to 21 days of bed-rest plus daily 1 hr exposures to AG (2.5 g). This particular experiment was part of an integrated AG Pilot Project sponsored by NASA/Johnson Space Center. The in vivo torque-velocity relationships of the knee extensors and plantar flexors of the ankle were determined pre and post treatment. Also, pre- and post treatment biopsy samples were obtained from both the vastus lateralis and soleus muscles and were used, in part, for a series of analyses on gene expression (mRNA abundance) of key factors implicated in the anabolic versus catabolic state of the muscle. Post/Pre toque-velocity determinations revealed greater decrements in knee extensor performance in the C versus AG group (P less than 0.04). The plantar flexor muscle group of the AG subjects actually demonstrated a net gain in torque-velocity relationship; whereas, in the C group the overall post/pre responses declined (AG vs C; P less than 0.001). Measurements of muscle fiber cross-sectional area (for both muscles) demonstrated a loss of approx. 20% in the C group while no losses were evident in the AG group. RT-PCR analyses of muscle biopsy specimens demonstrated that markers of growth and cytoskeletal integrity (IGF-1, IGF-1 BP4, mechano growth factor, total RNA, and pro-collagen 3a) were higher in the AG group, whereas catabolic markers (myostatin and atrogen) were elevated in the C group. Importantly, these patterns were seen in both muscles. Based on these observations we conclude that paradigms of AG have the potential to maintain the functional, biochemical, and structural homeostasis of skeletal muscle in the face of chronic unloading states. These findings also

  19. Muscle oxygenation of superficial and deep regions in knee extensor and plantar flexor muscles during repeated isometric contractions.

    Science.gov (United States)

    Kubo, K

    2015-04-01

    The purpose of this study was to investigate changes in muscle oxygenation of knee extensor and plantar flexor muscles during repeated muscle contractions under the same condition. In addition, we compared changes in muscle oxygenation between superficial and deep regions of both muscles. Eleven healthy males participated in this study. During repeated knee extensions and plantar flexions (50 repetitions at 50% of the isometric maximum voluntary contraction for 3 s with 3 s relaxations), blood volume and oxygen saturation (StO₂) of the vastus lateralis and medial gastrocnemius muscles (superficial and deep region of each muscle) were measured using near infrared spectroscopy. The decrement of StO₂at the end of exercises was greater in plantar flexor muscle than in knee extensor muscle (Pmuscles, the decrement of StO₂at the end of exercises was greater in the deep region than in the superficial one (both Pmuscle and deep regions of each muscle were higher than that of knee extensor muscle and superficial regions of each muscle.

  20. Isokinetic Evaluation of Knee Extensor/Flexor Muscle Strength in Behcet’s Patients

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    Bekir Durmus

    2015-10-01

    Full Text Available Background: Behçet’s disease (BD is an idiopathic, multisystemic, progressive disease. The purpose of this study is to compare the knee flexor and extensor isokinetic muscle strengths of Behcet’s patients with that of healthy subjects. Methods: Twenty-five (13 male and 12 female patients with BD and 25 (15 male and 10 female healthy individuals were included in the study. Velocities of 90°/sec, 120°/sec, and 150°/sec were used for the isokinetic muscle strength testing. Patients with active inflammatory knee arthritis were excluded. Peak torque (Nm and peak torque adjusted to body weight (% were taken into consideration for comparison between study groups. Results: Compared to healthy controls, there was a statistically significant decrease in both the bilateral knee extensor and flexor muscle isokinetic peak torques(Nm as well as the peak torques adjusted to body weight (% at velocities of 90°/sec, 120°/sec and 150°/sec in patients with BD (p < 0.05. However, there was no significant difference in the agonist-antagonist ratio of the isokinetic peak torques of knee muscles between the two groups. Conclusion: In light of these findings, we have concluded that both knee flexor and extensor isokinetic muscle strengths are lower in BD. We therefore recommend careful monitoring of patients with BD in terms of muscle strength.

  1. Sex Differences in Neuromuscular Fatigability of the Knee Extensors Post-Stroke

    Science.gov (United States)

    Kirking, Meghan; Berrios Barillas, Reivian; Nelson, Philip Andrew; Hunter, Sandra Kay; Hyngstrom, Allison

    2017-01-01

    Background and Purpose: Despite the implications of optimizing strength training post-stroke, little is known about the differences in fatigability between men and women with chronic stroke. The purpose of this study was to determine the sex differences in knee extensor muscle fatigability and potential mechanisms in individuals with stroke. Methods: Eighteen participants (10 men, eight women) with chronic stroke (≥6 months) and 23 (12 men, 11 women) nonstroke controls participated in the study. Participants performed an intermittent isometric contraction task (6 s contraction, 3 s rest) at 30% of maximal voluntary contraction (MVC) torque until failure to maintain the target torque. Electromyography was used to determine muscle activation and contractile properties were assessed with electrical stimulation of the quadriceps muscles. Results: Individuals with stroke had a briefer task duration (greater fatigability) than nonstroke individuals (24.1 ± 17 min vs. 34.9 ± 16 min). Men were more fatigable than women for both nonstroke controls and individuals with stroke (17.9 ± 9 min vs. 41.6 ± 15 min). Individuals with stroke had less fatigue-related changes in muscle contractile properties and women with stroke differed in their muscle activation strategy during the fatiguing contractions. Conclusions: Men and women fatigue differently post-stroke and this may be due to the way they neurally activate muscle groups. PMID:28085089

  2. DIFFERENCE IN THE MAGNITUDE OF MUSCLE DAMAGE BETWEEN ELBOW FLEXORS AND KNEE EXTENSORS ECCENTRIC EXERCISES

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    Tolga Saka

    2009-03-01

    Full Text Available The aim of this study was to investigate the difference in the magnitude of muscle damage between maximal eccentric exercises of the elbow flexors (EF and knee extensors (KE. Twelve sedentary male volunteers participated in the study. Range of motion (ROM, isometric peak torque (IPT, delayed onset of muscle soreness (DOMS, creatine kinase activity (CK, and myoglobin concentration (Mb were evaluated before, immediately after, and on the 1st , 2nd, 3rd , and 7th days following exercise. Total work (TW during exercises was recorded and corrected by muscle volume (TWc. TWc was greater (p < 0.01 for EF [24 (2 joule·cm-3] than for KE [7 (0.4 joule·cm-3]. Increases in CK on the 2nd , 3rd , and 7th days (p < 0.01 and increases in Mb on the 1st , 2nd , 3rd , and 7th days were significantly (p<0.01 larger for EF than for KE. The decline in IPT was greater (p < 0.05- 0.01 for EF at all test occasions compared with KE. The results of this study demonstrate that the magnitude of muscle damage is greater and the recovery is slower following maximal eccentric exercise of the EF than of the KE for sedentary males

  3. Effects of Constant and Doublet Frequency Electrical Stimulation Patterns on Force Production of Knee Extensor Muscles.

    Science.gov (United States)

    Cometti, Carole; Babault, Nicolas; Deley, Gaëlle

    2016-01-01

    This study compared knee extensors' neuromuscular fatigue in response to two 30-minute stimulation patterns: constant frequency train (CFT) and doublet frequency train (DFT). Fifteen men underwent two separate sessions corresponding to each pattern. Measurements included torque evoked by each contraction and maximal voluntary contractions (MVC) measured before and immediately after the stimulation sessions. In addition, activation level and torque evoked during doublets (Pd) and tetanic contractions at 80-Hz (P80) and 20-Hz (P20) were determined in six subjects. Results indicated greater mean torque during the DFT stimulation session as compared with CFT. But, no difference was obtained between the two stimulation patterns for MVC and evoked torque decreases. Measurements conducted in the subgroup depicted a significant reduction of Pd, P20 and P80. Statistical analyses also revealed bigger P20 immediate reductions after CFT than after DFT. We concluded that DFT could be a useful stimulation pattern to produce and maintain greater force with quite similar fatigue than CFT.

  4. Effects of Constant and Doublet Frequency Electrical Stimulation Patterns on Force Production of Knee Extensor Muscles.

    Directory of Open Access Journals (Sweden)

    Carole Cometti

    Full Text Available This study compared knee extensors' neuromuscular fatigue in response to two 30-minute stimulation patterns: constant frequency train (CFT and doublet frequency train (DFT. Fifteen men underwent two separate sessions corresponding to each pattern. Measurements included torque evoked by each contraction and maximal voluntary contractions (MVC measured before and immediately after the stimulation sessions. In addition, activation level and torque evoked during doublets (Pd and tetanic contractions at 80-Hz (P80 and 20-Hz (P20 were determined in six subjects. Results indicated greater mean torque during the DFT stimulation session as compared with CFT. But, no difference was obtained between the two stimulation patterns for MVC and evoked torque decreases. Measurements conducted in the subgroup depicted a significant reduction of Pd, P20 and P80. Statistical analyses also revealed bigger P20 immediate reductions after CFT than after DFT. We concluded that DFT could be a useful stimulation pattern to produce and maintain greater force with quite similar fatigue than CFT.

  5. Knee Extensor Electromyographic Activity-to-Work Ratio is Greater With Isotonic Than Isokinetic Contractions.

    Science.gov (United States)

    Schmitz, Randy J.; Westwood, Kevin C.

    2001-12-01

    OBJECTIVE: To determine whether isotonic or isokinetic contractions produced greater electromyographic (EMG) activity per unit of work during isotonic and isokinetic knee-extension exercise. DESIGN AND SETTING: Subjects performed three 3-second maximal voluntary isometric contractions of the dominant knee extensors for EMG normalization. Exercise testing performed on the Biodex System 3 Dynamometer involved 10 isokinetic contractions at 180 degrees.s(-1) and 10 isotonic contractions with the resistance set at 50% of the previously recorded maximal voluntary isometric contraction. SUBJECTS: Recreationally active college students (10 men and 11 women). MEASUREMENTS: Surface EMG signals were collected from the vastus medialis and lateralis muscles and then integrated (IEMG) over the concentric phase of each repetition for both exercises. The IEMG was divided by the total work performed during the concentric phase for each exercise (IEMG/W). RESULTS: We analyzed the IEMG/W data using a 1-between (sex), 2-within (exercise and muscle) repeated-measures analysis of variance. There was a significant main effect for exercise, with the isotonic IEMG/W value being significantly greater than the isokinetic IEMG/W value. Additionally, the IEMG/W relationship did not appear to be affected by sex or individual muscle tested. CONCLUSIONS: Per unit of work performed, the isotonic contractions resulted in greater motor unit recruitment or an increased rate of firing, or both. This finding may have implications for the early phase of rehabilitation, when goals include complete motor unit recruitment of injured or atrophied muscles.

  6. The effects of imagery training on fast isometric knee extensor torque development.

    Science.gov (United States)

    de Ruiter, Cornelis J; Hutter, Vana; Icke, Chris; Groen, Bart; Gemmink, Anne; Smilde, Hiltsje; de Haan, Arnold

    2012-01-01

    We hypothesized that imagery training would improve the fast onset of neuromuscular activation and thereby fast knee extensor isometric torque development. Forty young healthy participants, not involved in strength training, were assigned to one of four groups: physical training, imagery training, placebo training or control. The three training groups had three 15 min sessions per week for 4 weeks, with a 90 ° knee angle but were tested also at 120 °. At 90 ° knee angle, maximal torque increased (-8%) similarly in all three training groups. The torque-time integral (contractile impulse) over the first 40 ms after torque onset (TTI40) increased (P training (by -100%), but only at 90 °. This increase was significantly different from the delta values (change pre to post) in the control and placebo groups, whereas delta values in the imagery group were similar to those in the placebo group. The increases in TTI40 following physical training were related (r (2) = 0.81, P training led to a knee angle specific increase of contractile impulse that was significantly different from placebo and controls and that was related to improved onset of neuromuscular activation.

  7. Effect of remote voluntary contractions on knee extensor torque and rate of velocity development.

    Science.gov (United States)

    Cherry, Emily A; Brown, Lee E; Coburn, Jared W; Noffal, Guillermo J

    2010-09-01

    Remote voluntary contractions (RVCs) are described as a muscle action of the prime mover while performing a simultaneous muscle action with another part of the body. Previous studies have shown that RVCs may elicit augmented performance of the prime mover. The purpose of this study was to evaluate the effect of RVCs on knee extensor rate of velocity development (RVD) and peak torque. Fourteen men and 16 women who were regularly active and free of any knee pathology for the past year took part in this study. Subjects performed 3 maximal dynamic knee extensions at 3 velocities with and without an RVC condition. The RVC condition consisted of holding hand dynamometers in each hand and maximally gripping while performing a maximal knee extension movement. The NO-RVC condition was the same only without gripping. Men produced greater peak torque and RVD than did women across speeds and conditions. Analysis demonstrated that RVC had no effect on knee extension peak torque, but RVD decreased in the RVC condition (NO-RVC 2,012.07 [46.52] degrees xs-1xs-1; RVC 1,882.61 [51.84] degrees xs-1xs-1). Grip strength of the left hand at 180 degrees xs-1decreased from 42.03 (14.40) to 38.83 (14.65) kg in the RVC condition. In conclusion, RVC should not be used when attempting to maximize RVD, because it may hinder results when performing a single joint movement.

  8. Severe COPD Alters Muscle Fiber Conduction Velocity During Knee Extensors Fatiguing Contraction.

    Science.gov (United States)

    Boccia, Gennaro; Coratella, Giuseppe; Dardanello, Davide; Rinaldo, Nicoletta; Lanza, Massimo; Schena, Federico; Rainoldi, Alberto

    2016-10-01

    The aim of this study was to assess the changes in muscle fiber conduction velocity (CV), as a sign of fatigue during knee extensor contraction in patients with chronic obstructive pulmonary disease (COPD) as compared with healthy controls. Eleven male patients (5 with severe and 6 with moderate COPD; age 67 ± 5 years) and 11 age-matched healthy male controls (age 65 ± 4 years) volunteered for the study. CV was obtained by multichannel surface electromyography (EMG) from the vastus lateralis (VL) and medialis (VM) of the quadriceps muscle during isometric, 30-second duration knee extension at 70% of maximal voluntary contraction. The decline in CV in both the VL and VM was steeper in the severe COPD patients than in healthy controls (for VL: severe COPD vs. controls -0.45 ± 0.07%/s; p < 0.001, and for VM: severe COPD vs. controls -0.54 ± 0.09%/s, p < 0.001). No difference in CV decline was found between the moderate COPD patients and the healthy controls. These findings suggest that severe COPD may impair muscle functions, leading to greater muscular fatigue, as expressed by CV changes. The results may be due to a greater involvement of anaerobic metabolism and a shift towards fatigable type II fibers in the muscle composition of the severe COPD patients.

  9. Effect of mental fatigue on induced tremor in human knee extensors.

    Science.gov (United States)

    Budini, Francesco; Lowery, Madeleine; Durbaba, Rade; De Vito, Giuseppe

    2014-06-01

    In this study, the effects of mental fatigue on mechanically induced tremor at both a low (3-6Hz) and high (8-12Hz) frequency were investigated. The two distinct tremor frequencies were evoked using two springs of different stiffness, during 20s sustained contractions of the knee extensor muscles at 30% maximum voluntary contraction (MVC) before and after 100min of a mental fatigue task, in 12 healthy (29±3.7years) participants. Mental fatigue resulted in a 6.9% decrease in MVC and in a 9.4% decrease in the amplitude of the agonist muscle EMG during sustained 30% MVC contractions in the induced high frequency only. Following the mental fatigue task, the coefficient of variation and standard deviation of the force signal decreased at 8-12Hz induced tremor by 31.7% and 35.2% respectively, but not at 3-6Hz induced tremor. Similarly, the maximum value and area underneath the peak in the power spectrum of the force signal decreased by 55.5% and 53.1% respectively in the 8-12Hz range only. In conclusion, mental fatigue decreased mechanically induced 8-12Hz tremor and had no effect on induced 3-6Hz tremor. We suggest that the reduction could be attributed to the decreased activation of the agonist muscles.

  10. Sex Differences in Neuromuscular Fatigability of the Knee Extensors Post-Stroke

    Directory of Open Access Journals (Sweden)

    Meghan Kirking

    2017-01-01

    Full Text Available Background and Purpose: Despite the implications of optimizing strength training post-stroke, little is known about the differences in fatigability between men and women with chronic stroke. The purpose of this study was to determine the sex differences in knee extensor muscle fatigability and potential mechanisms in individuals with stroke. Methods: Eighteen participants (10 men, eight women with chronic stroke (≥6 months and 23 (12 men, 11 women nonstroke controls participated in the study. Participants performed an intermittent isometric contraction task (6 s contraction, 3 s rest at 30% of maximal voluntary contraction (MVC torque until failure to maintain the target torque. Electromyography was used to determine muscle activation and contractile properties were assessed with electrical stimulation of the quadriceps muscles. Results: Individuals with stroke had a briefer task duration (greater fatigability than nonstroke individuals (24.1 ± 17 min vs. 34.9 ± 16 min. Men were more fatigable than women for both nonstroke controls and individuals with stroke (17.9 ± 9 min vs. 41.6 ± 15 min. Individuals with stroke had less fatigue-related changes in muscle contractile properties and women with stroke differed in their muscle activation strategy during the fatiguing contractions. Conclusions: Men and women fatigue differently post-stroke and this may be due to the way they neurally activate muscle groups.

  11. Relation between knee extensors' strength, postural stability and variability of centre of pressure displacement during gait in adult women

    Directory of Open Access Journals (Sweden)

    Eliza C. de Souza

    2017-03-01

    Full Text Available Background: It has been shown that variability of walking is related to fall risk similarly as postural control and muscle strength. Joint potential of this group of variables for fall risk assessment is promising, however research interested in relations between them is lacking. Objective: The aim of this study was to investigate the relation between knee extensors' strength, centre of pressure (COP velocity during one-leg stance and variability of COP displacement during various phases of gait cycle in middle-age women. Methods: A single group of 40 healthy women (age 56 ± 4.2 years took part in the study. For assessment of knee extensors' strength (peak torque and average work during concentric and eccentric contractions an isokinetic dynamometer was used. Mean velocity of COP during one-leg stance in anterior-posterior (AP and medial-lateral (ML directions was assessed on a force plate on a rigid surface with eyes open (two 30 s trials. Variability of COP displacement was assessed for loading response, midstance, terminal stance and preswing gait cycle phases (determined by vertical ground reaction force in AP and ML directions. It was measured by two force plates positioned in the middle of an 8 m walkway (5 trials at a self-selected speed. For statistical analysis of relationships between variables Pearson correlation was applied. Results: Our results showed significant correlations between eccentric peak torque and COP velocity in AP direction during one-leg stance, eccentric and concentric peak torque and COP variability during loading response in both ML and AP directions and during terminal stance in AP direction. Conclusion: Loading response and terminal stance seems to be more related to knee extensors' strength. Variables derived from postural stability assessment during one-leg stance are independent from variables derived from assessment of COP displacement variability during walking.

  12. Heterogeneous recruitment of quadriceps muscle portions and fibre types during moderate intensity knee-extensor exercise: effect of thigh occlusion

    DEFF Research Database (Denmark)

    Krustrup, Peter; Söderlund, Karin; Relu, Mihai U.;

    2009-01-01

    The involvement of quadriceps femoris muscle portions and fibre type recruitment was studied during submaximal knee-extensor exercise without and with thigh occlusion (OCC) and compared with responses during intense exercise. Six healthy male subjects performed 90-s of moderate exercise without...... (MOD; 29+/-4 W) and with thigh OCC, and moderate exercise followed by 90-s of intense exercise (HI; 65+/-8 W). Temperatures were continuously measured in m. vastus lateralis (VL), vastus medialis (VM) and rectus femoris (RF) and successive muscle biopsies were obtained from VL. During MOD, muscle...

  13. Influence of acetaminophen and ibuprofen on in vivo patellar tendon adaptations to knee extensor resistance exercise in older adults

    DEFF Research Database (Denmark)

    Carroll, C C; Dickinson, J M; LeMoine, J K

    2011-01-01

    training. Thirty-six individuals were randomly assigned to a placebo (67 ± 2 yr old), acetaminophen (64 ± 1 yr old; 4,000 mg/day), or ibuprofen (64 ± 1 yr old; 1,200 mg/day) group in a double-blind manner and completed 12 wk of knee extensor resistance training. Before and after training in vivo patellar...... adults induces modest changes in the mechanical properties of the patellar tendon. Over-the-counter doses of acetaminophen, but not ibuprofen, have a strong influence on tendon mechanical and material property adaptations to resistance training. These findings add to a growing body of evidence...

  14. Trajectory of self-reported pain and function and knee extensor muscle strength in young patients undergoing arthroscopic surgery for meniscal tears

    DEFF Research Database (Denmark)

    Thorlund, Jonas Bloch; Østengaard, Lasse; Cardy, Nathan

    2017-01-01

    OBJECTIVES: To investigate the trajectory of patient reported pain and function and knee extensor muscle strength over time in young individuals undergoing arthroscopic meniscal surgery. DESIGN: Systematic review and meta-analysis METHODS: Six databases were searched up to October 13th, 2016....... PATIENTS AND INTERVENTION: People aged 30 years or younger undergoing surgery for a meniscal tear. OUTCOMES: and comparator: (1) Self-reported pain and function in patients undergoing meniscal surgery compared to a non-operative control group (2). Knee extensor strength in the leg undergoing surgery...... compared to a healthy control group or the contra-lateral leg. Methodological quality was assessed using the SIGN 50 guidelines. RESULTS: No studies were found on patient reported pain and function. Six studies, including 137 patients were included in the analysis on knee extensor muscle strength. Knee...

  15. Knee extensor and flexor muscle power explains stair ascension time in patients with unilateral late-stage knee osteoarthritis: a cross-sectional study.

    Science.gov (United States)

    Valtonen, Anu M; Pöyhönen, Tapani; Manninen, Mikko; Heinonen, Ari; Sipilä, Sarianna

    2015-02-01

    To determine the extent of asymmetrical deficits in knee extensor and flexor muscles, and to examine whether asymmetrical muscle deficits are associated with mobility limitations in persons with late-stage knee osteoarthritis (OA). Cross-sectional. Research laboratory. A clinical sample (N=56; age range, 50-75y) of eligible persons with late-stage knee OA awaiting knee replacement. Not applicable. Knee extensor and flexor power and torque assessed isokinetically; thigh muscle cross-sectional area (CSA) assessed by computed tomography; mobility limitation assessed by walking speed and stair ascension time; and pain assessed with the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire. The asymmetrical deficits in knee extensor and flexor power and torque were between 18% and 29% (Pmuscle CSA, the asymmetrical deficit was 4% (Ppower deficits and weaker knee extensor and flexor power on the contralateral side were associated with slower stair ascension times. Moreover, weaker knee extensor and flexor power on the ipsilateral side were associated with slower stair ascension times. Greater knee pain in the OA joint was independently associated with slower stair ascending time in both models. The knee extensor and flexor muscle power of both the ipsilateral and contralateral sides and the pain in the OA knee were independently associated with stair ascension times. These results highlight the importance of assessing muscle power on both sides and knee pain in the prevention of mobility limitations in patients with knee OA. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  16. Comparison of elasticity of human tendon and aponeurosis in knee extensors and ankle plantar flexors in vivo.

    Science.gov (United States)

    Kubo, Keitaro; Kanehisa, Hiroaki; Fukunaga, Tetsuo

    2005-05-01

    The purposes of this study were to compare the elasticity of tendon and aponeurosis in human knee extensors and ankle plantar flexors in vivo and to examine whether the maximal strain of tendon was correlated to that of aponeurosis. The elongation of tendon and aponeurosis during isometric knee extension (n = 23) and ankle plantar flexion (n = 22), respectively, were determined using a real-time ultrasonic apparatus, while the participants performed ramp isometric contractions up to voluntary maximum. To calculate the strain values from the measured elongation, we measured the respective length of tendon and aponeurosis. For the knee extensors, the maximal strain of aponeurosis (12.1 +/- 2.8 %) was significantly greater than that of the patella tendon (8.3 +/- 2.4 %), p aponeurosis in ankle plantar flexors (2.7 +/- 1.4 %), p plantar flexors there was no significant correlation between maximal strain of tendon and aponeurosis. These results would be important for understanding the different roles of tendon and aponeurosis during human movements and for more accurate muscle modeling.

  17. Effect of acute dietary nitrate intake on maximal knee extensor speed and power in healthy men and women.

    Science.gov (United States)

    Coggan, Andrew R; Leibowitz, Joshua L; Kadkhodayan, Ana; Thomas, Deepak P; Ramamurthy, Sujata; Spearie, Catherine Anderson; Waller, Suzanne; Farmer, Marsha; Peterson, Linda R

    2015-08-01

    Nitric oxide (NO) has been demonstrated to enhance the maximal shortening velocity and maximal power of rodent muscle. Dietary nitrate (NO3(-)) intake has been demonstrated to increase NO bioavailability in humans. We therefore hypothesized that acute dietary NO3(-) intake (in the form of a concentrated beetroot juice (BRJ) supplement) would improve muscle speed and power in humans. To test this hypothesis, healthy men and women (n = 12; age = 22-50 y) were studied using a randomized, double-blind, placebo-controlled crossover design. After an overnight fast, subjects ingested 140 mL of BRJ either containing or devoid of 11.2 mmol of NO3(-). After 2 h, knee extensor contractile function was assessed using a Biodex 4 isokinetic dynamometer. Breath NO levels were also measured periodically using a Niox Mino analyzer as a biomarker of whole-body NO production. No significant changes in breath NO were observed in the placebo trial, whereas breath NO rose by 61% (P power at the highest angular velocity tested (i.e., 6.28 rad/s). Calculated maximal knee extensor power was therefore greater (i.e., 7.90 ± 0.59 vs. 7.44 ± 0.53 W/kg; P power in healthy men and women.

  18. Comparative assessment of knee extensor and flexor muscle strength measured using a hand-held vs. isokinetic dynamometer.

    Science.gov (United States)

    Muff, Guillaume; Dufour, Stéphane; Meyer, Alain; Severac, François; Favret, Fabrice; Geny, Bernard; Lecocq, Jehan; Isner-Horobeti, Marie-Eve

    2016-09-01

    [Purpose] To compare measurements of knee extensor and flexor muscle strength performed using a hand-held dynamometer and an isokinetic dynamometer in apparently healthy subjects. [Subjects and Methods] Thirty adult volunteers underwent knee muscle strength evaluation using an isokinetic or a hand-held dynamometer. [Results] Strong positive correlations were found between the 2 methods, with correlation coefficients r ranging from 0.72 (95% confidence interval [CI], 0.48-0.86) to 0.87 (95% CI, 0.75-0.94), depending on the muscle group and the isokinetic evaluation mode. The reproducibility of the hand-held dynamometer findings was good, judged by a coefficient of variation of 3.2-4.2%. However, the correlation between the 2 methods for the assessment of flexor/extensor ratios ranged from -0.04 to 0.46. [Conclusion] Knee extensor and flexor muscle strength recorded with a hand-held dynamometer is reproducible and significantly correlated with the isokinetic values, indicating that this method may in some cases be a useful replacement for isokinetic strength measurement. However, for strength ratio assessment, and when judged against the isokinetic standard, a hand-held dynamometer is not a valid option.

  19. Influence of patellofemoral bracing on pain, knee extensor torque, and gait function in females with patellofemoral pain.

    Science.gov (United States)

    Powers, Christopher M; Doubleday, Kathryn L; Escudero, Carina

    2008-01-01

    Our purpose was to evaluate the effects of a patellofemoral brace on pain response, knee extensor torque production, and gait function in females with patellofemoral pain (PFP). Sixteen females between the ages of 14 and 46 with diagnosis of PFP participated. Knee extensor torque was measured by using a LIDO isokinetic dynamometer. Pain levels were documented by using the Visual Analog Pain Scale. Stride characteristics during the conditions of free walk, fast walk, ascend stairs, descend stairs, ascend ramp, and descend ramp were obtained with a stride analyzer unit. EMG activity of the vasti musculature was recorded by using indwelling, bipolar, wire electrodes. Knee joint motion was assessed by using a VICON motion analysis system. All testing was performed with and without the Bauerfeind Genutrain P3 patellofemoral brace. There were no significant differences in torque production, pain levels, and stride characteristics between braced and non-braced trials. In addition, there were no significant differences in mean vasti EMG between braced and non-braced trials. When averaged across all conditions, a small but statistically significant increase in knee flexion was found during the braced trials. Although the current study did not find significant improvements in the clinical measures evaluated, 8 of the 16 subjects did experience a decrease in knee pain. This finding suggests that certain patients with PFP may respond favorably to bracing, and criteria must be established to determine which patients would best benefit from such an intervention.

  20. Low-intensity eccentric contractions attenuate muscle damage induced by subsequent maximal eccentric exercise of the knee extensors in the elderly.

    Science.gov (United States)

    Chen, Trevor C; Tseng, Wei-Chin; Huang, Guan-Ling; Chen, Hsin-Lian; Tseng, Kou-Wei; Nosaka, Kazunori

    2013-04-01

    This study investigated whether low-intensity eccentric contractions of the knee extensors would attenuate the magnitude of muscle damage induced by maximal eccentric exercise of the same muscle performed 7 days later using elderly individuals. Healthy older men (66.4 ± 4.6 years) were assigned to control or experimental (Exp) group (n = 13 per group). The control group performed six sets of ten maximal eccentric contractions (MaxECC) of the knee extensors of non-dominant leg. The Exp group performed six sets of ten low-intensity eccentric contractions of the knee extensors on a leg extension machine by lowering a weight of 10 % maximal voluntary isometric knee extension strength (10 %ECC) 7 days prior to MaxECC. Changes in maximal voluntary isokinetic concentric torque (MVC-CON), angle at peak torque, range of motion (ROM), upper thigh circumference, muscle soreness, plasma creatine kinase activity and myoglobin (Mb) concentration and B-mode ultrasound echo-intensity before and for 5 days after MaxECC were compared between groups by a mixed factor ANOVA. No significant changes in any variables were observed following 10 %ECC. Following MaxECC, all variables changed significantly, and changes in all variables except for angle at peak torque were significantly different between groups. MVC-CON and ROM decreased smaller and recovered faster (P eccentric contractions was effective for attenuating muscle damage induced by subsequent MaxECC of the knee extensors for elderly individuals.

  1. Twitch potentiation induced by stimulated and voluntary isometric contractions at various torque levels in human knee extensor muscles.

    Science.gov (United States)

    Miyamoto, Naokazu; Yanai, Toshimasa; Kawakami, Yasuo

    2011-03-01

    The purpose of this study was to compare the extent of twitch potentiation (TP) after stimulated or voluntary contractions at identical intensities for the human knee extensor muscles. Isometric knee extensions of 10 s were performed at 20%, 40%, and 60% of maximal voluntary contraction (MVC) torque level, through percutaneous electrical stimulation of the quadriceps at 80 Hz or voluntary contraction. Twitch responses were evoked by stimulating the femoral nerve percutaneously with supramaximal intensity. The extent of TP after the stimulated contraction was greater than that after the voluntary contraction at the 20% MVC torque level, whereas a stimulated contraction induced a smaller extent of TP than did a voluntary contraction at contraction intensities higher than 40% MVC. We suggest that this contraction intensity dependence of differences in TP after stimulated and voluntary isometric conditioning contractions is responsible for differences in the recruitment pattern of motor units during the conditioning contractions.

  2. Reduced rate of knee extensor torque development in older adults with knee osteoarthritis is associated with intrinsic muscle contractile deficits.

    Science.gov (United States)

    Callahan, Damien M; Tourville, Timothy W; Slauterbeck, James R; Ades, Philip A; Stevens-Lapsley, Jennifer; Beynnon, Bruce D; Toth, Michael J

    2015-12-01

    We examined the effect of knee osteoarthritis on the rate of torque development (RTD) of the knee extensors in older adults with advanced-stage knee osteoarthritis (OA; n=15) and recreationally-active controls (n=15) of similar age, sex and health status, as well as the relationship between RTD and the size and contractility of single muscle fibers. OA participants had lower RTD when expressed in absolute terms (Nm/ms). There were sex differences in peak RTD (Ptorque (PT). In knee OA volunteers, we found strong correlations between the RTD expressed relative to PT and the velocity of contraction of single myosin heavy chain (MHC) I and IIA/X muscle fibers (r=0.652 and 0.862; both Pknee osteoarthritis and healthy older adults is related, in part, to the size and function of single muscle fibers.

  3. High altitude increases alteration in maximal torque but not in rapid torque development in knee extensors after repeated treadmill sprinting

    Directory of Open Access Journals (Sweden)

    Olivier eGIRARD

    2016-03-01

    Full Text Available We assessed knee extensor neuromuscular adjustments following repeated treadmill sprints in different normobaric hypoxia conditions, with special reference to rapid muscle torque production capacity. Thirteen team- and racquet-sport athletes undertook 8 x 5-s all-out sprints (passive recovery = 25 s on a non-motorized treadmill in normoxia (NM; FiO2 = 20.9%, at low (LA; FiO2 = 16.6% and high (HA; FiO2 = 13.3% normobaric hypoxia (simulated altitudes of ~1800 m and ~3600 m, respectively. Explosive (∼1 s; fast instruction and maximal (∼5 s; hard instruction voluntary isometric contractions (MVC of the knee extensors, with concurrent electromyographic (EMG activity recordings of the vastus lateralis (VL and rectus femoris (RF muscles, were performed before and 1-min post-exercise. Rate of torque development (RTD and EMG (i.e., Root Mean Square or RMS rise from 0 to 30, -50, -100 and -200 ms were recorded, and were also normalized to maximal torque and EMG values, respectively. Distance covered during the first 5-s sprint was similar (P>0.05 in all conditions. A larger (P0.05. Irrespectively of condition (P>0.05, peak RTD (-6±11%; P0.05, whereas it increased (P<0.05 for RF muscle during all epochs post-exercise, independently of the conditions. In summary, alteration in repeated-sprint ability and post-exercise MVC decrease were greater at high altitude than in normoxia or at low altitude. However, the post-exercise alterations in RTD were similar between normoxia and low-to-high hypoxia.

  4. High Altitude Increases Alteration in Maximal Torque but Not in Rapid Torque Development in Knee Extensors after Repeated Treadmill Sprinting

    Science.gov (United States)

    Girard, Olivier; Brocherie, Franck; Millet, Grégoire P.

    2016-01-01

    We assessed knee extensor neuromuscular adjustments following repeated treadmill sprints in different normobaric hypoxia conditions, with special reference to rapid muscle torque production capacity. Thirteen team- and racquet-sport athletes undertook 8 × 5-s “all-out” sprints (passive recovery = 25 s) on a non-motorized treadmill in normoxia (NM; FiO2 = 20.9%), at low (LA; FiO2 = 16.8%) and high (HA; FiO2 = 13.3%) normobaric hypoxia (simulated altitudes of ~1800 m and ~3600 m, respectively). Explosive (~1 s; “fast” instruction) and maximal (~5 s; “hard” instruction) voluntary isometric contractions (MVC) of the knee extensors (KE), with concurrent electromyographic (EMG) activity recordings of the vastus lateralis (VL) and rectus femoris (RF) muscles, were performed before and 1-min post-exercise. Rate of torque development (RTD) and EMG (i.e., Root Mean Square or RMS) rise from 0 to 30, −50, −100, and −200 ms were recorded, and were also normalized to maximal torque and EMG values, respectively. Distance covered during the first 5-s sprint was similar (P > 0.05) in all conditions. A larger (P sprint decrement score and a shorter (P sprints occurred in HA (−8 ± 4% and 178 ± 11 m) but not in LA (−7 ± 3% and 181 ± 10 m) compared to NM (−5 ± 2% and 183 ± 9 m). Compared to NM (−9 ± 7%), a larger (P 0.05). Irrespectively of condition (P > 0.05), peak RTD (−6 ± 11%; P 0.05), whereas it increased (P repeated-sprint ability and post-exercise MVC decrease were greater at high altitude than in normoxia or at low altitude. However, the post-exercise alterations in RTD were similar between normoxia and low-to-high hypoxia. PMID:27014095

  5. Improved knee extensor strength with resistance training associates with muscle specific miRNAs in older adults.

    Science.gov (United States)

    Zhang, Tan; Birbrair, Alexander; Wang, Zhong-Min; Messi, María L; Marsh, Anthony P; Leng, Iris; Nicklas, Barbara J; Delbono, Osvaldo

    2015-02-01

    Regular exercise, particularly resistance training (RT), is the only therapy known to consistently improve muscle strength and quality (force per unit of mass) in older persons, but there is considerable variability in responsiveness to training. Identifying sensitive diagnostic biomarkers of responsiveness to RT may inform the design of a more efficient exercise regimen to improve muscle strength in older adults. MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression. We quantified six muscle specific miRNAs (miR-1, -133a, -133b, -206, -208b and -499) in both muscle tissue and blood plasma, and their relationship with knee extensor strength in seven older (age=70.5 ± 2.5 years) adults before and after 5 months of RT. MiRNAs differentially responded to RT; muscle miR-133b decreased, while all plasma miRNAs tended to increase. Percent changes in knee extensor strength with RT showed strong positive correlations with percent changes in muscle miR-133a, -133b, and -206 and with percent changes in plasma and plasma/muscle miR-499 ratio. Baseline level of plasma or plasma/muscle miR-499 ratio further predicts muscle response to RT, while changes in muscle miR-133a, -133b, and -206 may correlate with muscle TNNT1 gene alternative splicing in response to RT. Our results indicate that RT alters muscle specific miRNAs in muscle and plasma, and that these changes account for some of the variation in strength responses to RT in older adults.

  6. Superior Effects of Eccentric to Concentric Knee Extensor Resistance Training on Physical Fitness, Insulin Sensitivity and Lipid Profiles of Elderly Men

    Science.gov (United States)

    Chen, Trevor Chung-Ching; Tseng, Wei-Chin; Huang, Guan-Ling; Chen, Hsin-Lian; Tseng, Kuo-Wei; Nosaka, Kazunori

    2017-01-01

    It has been reported that eccentric training of knee extensors is effective for improving blood insulin sensitivity and lipid profiles to a greater extent than concentric training in young women. However, it is not known whether this is also the case for elderly individuals. Thus, the present study tested the hypothesis that eccentric training of the knee extensors would improve physical function and health parameters (e.g., blood lipid profiles) of older adults better than concentric training. Healthy elderly men (60–76 years) were assigned to either eccentric training or concentric training group (n = 13/group), and performed 30–60 eccentric or concentric contractions of knee extensors once a week. The intensity was progressively increased over 12 weeks from 10 to 100% of maximal concentric strength for eccentric training and from 50 to 100% for concentric training. Outcome measures were taken before and 4 days after the training period. The results showed that no sings of muscle damage were observed after any sessions. Functional physical fitness (e.g., 30-s chair stand) and maximal concentric contraction strength of the knee extensors increased greater (P ≤ 0.05) after eccentric training than concentric training. Homeostasis model assessment, oral glucose tolerance test and whole blood glycosylated hemoglobin showed improvement of insulin sensitivity only after eccentric training (P ≤ 0.05). Greater (P ≤ 0.05) decreases in fasting triacylglycerols, total, and low-density lipoprotein cholesterols were evident after eccentric training than concentric training, and high-density lipoprotein cholesterols increased only after eccentric training. These results support the hypothesis and suggest that it is better to focus on eccentric contractions in exercise medicine. PMID:28443029

  7. Effects of strength training program on hip extensors and knee extensors strength of lower limb in children with spastic diplegic cerebral palsy

    OpenAIRE

    Aye, Thanda; Thein, Soe; Hlaing, Thaingi

    2016-01-01

    [Purpose] The purpose of this study was to determine whether strength training programs for hip extensors and knee extensors improve gross motor function of children with cerebral palsy in Myanmar. [Subjects and Methods] Forty children (25 boys and 15 girls, mean age: 6.07 ± 2.74 years) from National Rehabilitation Hospital, Yangon, Myanmar, who had been diagnosed with spastic diplegic cerebral palsy, Gross Motor Classification System I and II participated in a 6-week strength training progra...

  8. Superior Effects of Eccentric to Concentric Knee Extensor Resistance Training on Physical Fitness, Insulin Sensitivity and Lipid Profiles of Elderly Men.

    Science.gov (United States)

    Chen, Trevor Chung-Ching; Tseng, Wei-Chin; Huang, Guan-Ling; Chen, Hsin-Lian; Tseng, Kuo-Wei; Nosaka, Kazunori

    2017-01-01

    It has been reported that eccentric training of knee extensors is effective for improving blood insulin sensitivity and lipid profiles to a greater extent than concentric training in young women. However, it is not known whether this is also the case for elderly individuals. Thus, the present study tested the hypothesis that eccentric training of the knee extensors would improve physical function and health parameters (e.g., blood lipid profiles) of older adults better than concentric training. Healthy elderly men (60-76 years) were assigned to either eccentric training or concentric training group (n = 13/group), and performed 30-60 eccentric or concentric contractions of knee extensors once a week. The intensity was progressively increased over 12 weeks from 10 to 100% of maximal concentric strength for eccentric training and from 50 to 100% for concentric training. Outcome measures were taken before and 4 days after the training period. The results showed that no sings of muscle damage were observed after any sessions. Functional physical fitness (e.g., 30-s chair stand) and maximal concentric contraction strength of the knee extensors increased greater (P ≤ 0.05) after eccentric training than concentric training. Homeostasis model assessment, oral glucose tolerance test and whole blood glycosylated hemoglobin showed improvement of insulin sensitivity only after eccentric training (P ≤ 0.05). Greater (P ≤ 0.05) decreases in fasting triacylglycerols, total, and low-density lipoprotein cholesterols were evident after eccentric training than concentric training, and high-density lipoprotein cholesterols increased only after eccentric training. These results support the hypothesis and suggest that it is better to focus on eccentric contractions in exercise medicine.

  9. Effects of strength training program on hip extensors and knee extensors strength of lower limb in children with spastic diplegic cerebral palsy.

    Science.gov (United States)

    Aye, Thanda; Thein, Soe; Hlaing, Thaingi

    2016-01-01

    [Purpose] The purpose of this study was to determine whether strength training programs for hip extensors and knee extensors improve gross motor function of children with cerebral palsy in Myanmar. [Subjects and Methods] Forty children (25 boys and 15 girls, mean age: 6.07 ± 2.74 years) from National Rehabilitation Hospital, Yangon, Myanmar, who had been diagnosed with spastic diplegic cerebral palsy, Gross Motor Classification System I and II participated in a 6-week strength training program (45 minutes per day, 3 days per week) on hip and knee extensors. Assessment was made, before and after intervention, of the amount of training weight in pounds, as well as Gross Motor Function Measure (GMFM) dimensions D (standing) and E (walking, running, jumping). [Results] All scores had increased significantly after the strength-training program. [Conclusion] A simple method of strength-training program for hip and knee extensors might lead to improved muscle strength and gross motor function in children with spastic diplegic cerebral palsy.

  10. Effects of strength training program on hip extensors and knee extensors strength of lower limb in children with spastic diplegic cerebral palsy

    Science.gov (United States)

    Aye, Thanda; Thein, Soe; Hlaing, Thaingi

    2016-01-01

    [Purpose] The purpose of this study was to determine whether strength training programs for hip extensors and knee extensors improve gross motor function of children with cerebral palsy in Myanmar. [Subjects and Methods] Forty children (25 boys and 15 girls, mean age: 6.07 ± 2.74 years) from National Rehabilitation Hospital, Yangon, Myanmar, who had been diagnosed with spastic diplegic cerebral palsy, Gross Motor Classification System I and II participated in a 6-week strength training program (45 minutes per day, 3 days per week) on hip and knee extensors. Assessment was made, before and after intervention, of the amount of training weight in pounds, as well as Gross Motor Function Measure (GMFM) dimensions D (standing) and E (walking, running, jumping). [Results] All scores had increased significantly after the strength-training program. [Conclusion] A simple method of strength-training program for hip and knee extensors might lead to improved muscle strength and gross motor function in children with spastic diplegic cerebral palsy. PMID:27065561

  11. Speed, not magnitude, of knee extensor torque production is associated with self-reported knee function early after anterior cruciate ligament reconstruction.

    Science.gov (United States)

    Hsieh, Chao-Jung; Indelicato, Peter A; Moser, Michael W; Vandenborne, Krista; Chmielewski, Terese L

    2015-11-01

    To examine the magnitude and speed of knee extensor torque production at the initiation of advanced anterior cruciate ligament (ACL) reconstruction rehabilitation and the associations with self-reported knee function. Twenty-eight subjects who were 12 weeks post-ACL reconstruction and 28 age- and sex-matched physically active controls participated in this study. Knee extensor torque was assessed bilaterally with an isokinetic dynamometer at 60°/s. The variables of interest were peak torque, average rate of torque development, time to peak torque and quadriceps symmetry index. Knee function was assessed with the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF). Peak torque and average rate of torque development were lower on the surgical side compared to the non-surgical side and controls. Quadriceps symmetry index was lower in subjects with ACL reconstruction compared to controls. On the surgical side, average rate of torque development was positively correlated with IKDC-SKF score (r = 0.379) while time to peak torque was negatively correlated with IKDC-SKF score (r = -0.407). At the initiation of advanced ACL reconstruction rehabilitation, the surgical side displayed deficits in peak torque and average rate of torque development. A higher rate of torque development and shorter time to peak torque were associated with better self-reported knee function. The results suggest that the rate of torque development should be addressed during advanced ACL reconstruction rehabilitation and faster knee extensor torque generation may lead to better knee function. III.

  12. Protective effect by maximal isometric contractions against maximal eccentric exercise-induced muscle damage of the knee extensors.

    Science.gov (United States)

    Tseng, Kuo-Wei; Tseng, Wei-Chin; Lin, Ming-Ju; Chen, Hsin-Lian; Nosaka, Kazunori; Chen, Trevor C

    2016-01-01

    This study investigated whether maximal voluntary isometric contractions (MVIC) performed before maximal eccentric contractions (MaxEC) would attenuate muscle damage of the knee extensors. Untrained men were placed to an experimental group that performed 6 sets of 10 MVIC at 90° knee flexion 2 weeks before 6 sets of 10 MaxEC or a control group that performed MaxEC only (n = 13/group). Changes in muscle damage markers were assessed before to 5 days after each exercise. Small but significant changes in maximal voluntary concentric contraction torque, range of motion (ROM) and plasma creatine kinase (CK) activity were evident at immediately to 2 days post-MVIC (p < 0.05), but other variables (e.g. thigh girth, myoglobin concentration, B-mode echo intensity) did not change significantly. Changes in all variables after MaxEC were smaller (p < 0.05) by 45% (soreness)-67% (CK) for the experimental than the control group. These results suggest that MVIC conferred potent protective effect against MaxEC-induced muscle damage.

  13. EFFECTS OF BETWEEN-SET INTERVENTIONS ON NEUROMUSCULAR FUNCTION DURING ISOKINETIC MAXIMAL CONCENTRIC CONTRACTIONS OF THE KNEE EXTENSORS

    Directory of Open Access Journals (Sweden)

    Carole Cometti

    2011-12-01

    Full Text Available The presents study investigated the effects of between-set interventions on neuromuscular function of the knee extensors during six sets of 10 isokinetic (120°·s-1 maximal concentric contractions separated by three minutes. Twelve healthy men (age: 23.9 ± 2.4 yrs were tested for four different between-set recovery conditions applied during two minutes: passive recovery, active recovery (cycling, electromyostimulation and stretching, in a randomized, crossover design. Before, during and at the end of the isokinetic session, torque and thigh muscles electromyographic activity were measured during maximal voluntary contractions and electrically-evoked doublets. Activation level was calculated using the twitch interpolation technique. While quadriceps electromyographic activity and activation level were significantly decreased at the end of the isokinetic session (-5.5 ± 14.2 % and -2.7 ± 4.8 %; p < 0.05, significant decreases in maximal voluntary contractions and doublets were observed after the third set (respectively -0.8 ± 12.1% and -5.9 ± 9.9%; p < 0.05. Whatever the recovery modality applied, torque was back to initial values after each recovery period. The present results showed that fatigue appeared progressively during the isokinetic session with peripheral alterations occurring first followed by central ones. Recovery interventions between sets did not modify fatigue time course as compared with passive recovery. It appears that the interval between sets (3 min was long enough to provide recovery regardless of the interventions

  14. Responses of knee extensor muscles to leg press training of various types in human.

    Science.gov (United States)

    Netreba, A; Popov, D; Bravyy, Ya; Lyubaeva, E; Terada, M; Ohira, T; Okabe, H; Vinogradova, O; Ohira, Y

    2013-03-01

    Responses of m. vastus lateralis to 8-week resistive training of various types at leg press mashine were investigated in 30 male subjects. Training loads were 25, 65 and 85% of one repetition maximum for low (LI), medium (MI), and high intensity (HI) training groups respectively, while angular velocities of contraction differed considerably between groups. The total work done during training session was identical. The maximum strengths during isokinetic knee extension in LI and HI groups were increased at most angular velocities. In group MI increments were obtained only during concentric contractions. Significant improvement of fatigue resistance and maximum oxygen consumption (V(O2max)) was seen only in group MI and LI, respectively. The training-related increase of cross-sectional area in type II fibers in m. vastus lateralis was in the order of HI > MI > LI group, and that of type I fibers was opposite. The increased myonuclear number was found for HI group. The data suggest that fiber hypertrophy, fatigue resistance and V(O2max) changes were related to the type of training.

  15. Fatigue reduces the complexity of knee extensor torque fluctuations during maximal and submaximal intermittent isometric contractions in man.

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    Pethick, Jamie; Winter, Samantha L; Burnley, Mark

    2015-04-15

    Neuromuscular fatigue increases the amplitude of fluctuations in torque output during isometric contractions, but the effect of fatigue on the temporal structure, or complexity, of these fluctuations is not known. We hypothesised that fatigue would result in a loss of temporal complexity and a change in fractal scaling of the torque signal during isometric knee extensor exercise. Eleven healthy participants performed a maximal test (5 min of intermittent maximal voluntary contractions, MVCs), and a submaximal test (contractions at a target of 40% MVC performed until task failure), each with a 60% duty factor (6 s contraction, 4 s rest). Torque and surface EMG signals were sampled continuously. Complexity and fractal scaling of torque were quantified by calculating approximate entropy (ApEn), sample entropy (SampEn) and the detrended fluctuation analysis (DFA) scaling exponent α. Fresh submaximal contractions were more complex than maximal contractions (mean ± SEM, submaximal vs. maximal: ApEn 0.65 ± 0.09 vs. 0.15 ± 0.02; SampEn 0.62 ± 0.09 vs. 0.14 ± 0.02; DFA α 1.35 ± 0.04 vs. 1.55 ± 0.03; all P contractions (ApEn to 0.24 ± 0.05; SampEn to 0.22 ± 0.04; DFA α to 1.55 ± 0.03; all P contractions (ApEn to 0.10 ± 0.02; SampEn to 0.10 ± 0.02; DFA α to 1.63 ± 0.02; all P < 0.01). This loss of complexity and shift towards Brownian-like noise suggests that as well as reducing the capacity to produce torque, fatigue reduces the neuromuscular system's adaptability to external perturbations.

  16. Functional imaging of muscle oxygenation and oxygen consumption in the knee extensor muscles during isometric contractions by spatially resolved near-infrared spectroscopy

    Science.gov (United States)

    Kek, Khai Jun; Miyakawa, Takahiro; Kudo, Nobuki; Yamamoto, Katsuyuki

    2007-02-01

    In this study, we showed that exercise type- and intensity-dependent regional differences in muscle oxygenation and oxygen consumption rate (Vo II) of the knee extensor muscles could be imaged in real time with a multi-channel spatially resolved near-infrared spectroscopy (SR-NIRS) imaging device. Healthy subjects performed isometric knee extension exercise for 30 s (without- or with-leg-press action) at different exercise intensities [10%, 40% and 70% of maximum voluntary contraction (MVC)]. "Separation-type" probes were attached to the skin over the major knee extensor muscles: vastus lateralis (VL), rectus femoris (RF) and vastus medialis (VM). Placement of the probes enabled simultaneously measurement of 12 sites over a skin area of about 30 cm2 (temporal resolution = 0.25 s). Local Vo II of each muscle, resting Vo II (Vo II, rest) and recovery Vo II (Vo II, rec ), were determined with arterial occlusion before the start and after the end of contraction, respectively. There was no significant difference between the values of Vo II rest, in the muscles. However, during knee extension exercise without-leg-press action, Vo II rec, value of the RF was significantly greater than the values of the VL and VM at all exercise intensities. In contrast, during exercise with-leg-press action, Vo II rec, values of the RF and VM were greater than those of the VL, especially during exercise at 40% and 70% MVC. In summary, the regional differences in muscle oxygenation and Vo II of the knee extensor muscles, probably due to the differences in relative contributions of muscles to exercise and in muscle architecture, were imaged using SR-NIRS.

  17. Electromechanical delay of the knee extensor muscles is not altered after harvesting the patellar tendon as a graft for ACL reconstruction: implications for sports performance.

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    Georgoulis, A D; Ristanis, S; Papadonikolakis, A; Tsepis, E; Moebius, U; Moraiti, C; Stergiou, N

    2005-09-01

    Although the scar tissue, which heals the donor site defect, has different elasticity from the neighbouring patellar tissue, it remains unclear if this scar tissue can lead to the changes of the electromechanical delay (EMD) of the knee extensor muscles. If such changes do exist, they can possibly affect both the utilization of the stored energy in the series elastic component, as well as the optimal performance of the knee joint movement. The purpose of this study was to investigate the influence of harvesting the patellar tendon during anterior cruciate ligament (ACL) reconstruction and the associated patellar tendon scar tissue development on the EMD of the rectus femoris (RF) and vastus medialis (VM) muscles. Seventeen patients who underwent an ACL reconstruction using the medial third of the patellar tendon were divided in two groups based upon their post-operative time interval. Maximal voluntary contraction from the knee extensors, surface EMG activity, and ultrasonographic measurements of the patellar tendon cross-section area were obtained from both knees. Our results revealed that no significant changes for the maximal voluntary contraction of the knee extensors and for the EMD of the RF and the VM muscles due to patellar scar tissue development after harvesting the tendon for ACL reconstruction. The EMD, as a component of the stretch reflex, is important for the utilization of the stored energy in the series elastic component and thus, optimal sports performance. However, from our results, it can be implied that the ACL reconstruction using a patellar tendon graft would not impair sports performance as far as EMD is concerned.

  18. The Total Work Measured During a High Intensity Isokinetic Fatigue Test Is Associated With Anaerobic Work Capacity

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    Bosquet, Laurent; Gouadec, Kenan; Berryman, Nicolas; Duclos, Cyril; Gremeaux, Vincent; Croisier, Jean Louis

    2016-01-01

    The purpose of the study was to determine whether total work measured during a high intensity isokinetic fatigue test (TWFAT) could be considered as a valid measure of anaerobic work capacity (AWC), such as determined by total work measured during a Wingate Anaerobic Test (TWWAnT). Twenty well-trained cyclists performed 2 randomly ordered sessions involving a high intensity isokinetic fatigue test consisting in 30 reciprocal maximal concentric contractions of knee flexors and extensors at 180°·s-1, and a Wingate Anaerobic Test. We found that TWFAT of knee extensors was largely lower than TWWAnT (4151 ± 691 vs 22313 ± 2901 J, respectively, p knee flexors (2151 ± 540 J) was largely lower than TWWAnT (p knee flexors and knee extensors into a single measure (6302 ± 818 J) did not changed neither improved these observations. We still found a large difference with TWWAnT (p knee extensors could be considered as a valid measure of AWC, since both measure were highly associated. However, the mean difference between both measures and their 95% LoA were too large to warrant interchangeability. Key points Total work performed during a high intensity isokinetic fatigue test can be considered as a valid measure of anaerobic work capacity (as determined by total work performance during a 30-s Wingate anaerobic test). The 95% limits of agreement are two large to allow a direct comparison between both measures. In other words, it is not possible to estimate the magnitude of performance improvement during a 30-s Wingate anaerobic test from that observed during a high intensity isokinetic fatigue test. In addition to provide sport scientists and coaches with measures of peak torque and ratios between agonists and antagonists muscles in a perspective of injury prevention, isokinetic dynamometry can also be used in the physiological assessment of athletes. However, some precautions should be taken in the interpretation of data. PMID:26957935

  19. No Critical Peripheral Fatigue Threshold during Intermittent Isometric Time to Task Failure Test with the Knee Extensors

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    Froyd, Christian; Beltrami, Fernando G.; Millet, Guillaume Y.; Noakes, Timothy D.

    2016-01-01

    critical peripheral fatigue threshold during intermittent isometric exercise to task failure with the knee extensors. PMID:28066260

  20. Effects of neuromuscular electrical stimulation of the knee extensor muscles on muscle soreness and different serum parameters in young male athletes: preliminary data

    Science.gov (United States)

    Zorn, Carina; Szekeres, Thomas; Keilani, Mohammad; Fialka‐Moser, Veronika; Crevenna, Richard

    2007-01-01

    Aim To evaluate the effects of neuromuscular electrical stimulation (NMES) on muscle soreness and on a variety of serum parameters during and after NMES of knee extensor muscles of young, well trained subjects over a study period of 96 h. Methods Five male cyclists were included in this clinical observation. NMES (biphasic, asymmetric impulses) was applied through surface electrodes to both knee extensor muscles of each subject for 30 min. To determine changes in serum concentration of muscle proteins, blood samples were drawn at defined measure points before and after NMES. Muscle soreness was evaluated using a visual analogue scale at all measure points. Results There was a maximum (p<0.05) for “muscle pain” during stimulation but no significant changes could be detected after the stimulation period. Serum creatine kinase showed a peak with a significant increase (p<0.05) 24 h after NMES. Serum lactate levels only increased slightly (p = 0.08) during NMES. Conclusions Although the changes of blood parameters measured in the present work correspond to those reported in the literature on eccentric strength training, no delayed onset muscle pain could be detected. Further studies should be carried out, also investigating different stimulation protocols in non‐trained healthy subjects and in patients with less muscle mass. PMID:18037643

  1. Management of a distal femoral non-union with coexisting failure of the knee extensor mechanism using osteobridge knee-arthrodesis system: A case report

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    Begkas Dimitrios

    2015-01-01

    Full Text Available Introduction. Reconstruction of bone defects is a long, challenging process both for the patient and for the treating surgeon. Bone defects frequently occur as a result of aggressive surgical debridement and bone resection in case of acute trauma, open fractures, chronic bone infections, tumors and non-unions. Early amputation is often superior to prolonged attempts at salvage because they can create serious problems in the patients’ lives. There are numerous alternative methods of limb-salvage nowadays. Case Report. We report a case of a fifty-year-old man with a distal femoral non-union and a co-existing failure of the knee extensor mechanism, who was treated using an intramedullary segmental defect bridging knee arthrodesis system (Osteobridge. At the final check-up twenty four months later, he had excellent clinical, functional and radiological results. Conclusion. Osteobridge is an excellent knee arthrodesis system, which is preferable to other methods in case of resection of the distal femur along with the failure of the knee extensor mechanism.

  2. Relationship between the Modified Modified Ashworth Scale and the Biomechanical Measure in Assessing Knee Extensor Muscle Spasticity in Patients with Post-Stroke Hemiparesia:A Pilot Study

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    N. Nakhostin Ansari

    2014-07-01

    Full Text Available Introduction & Objective: The Modified Modified Ashworth Scale (MMAS is a clinical meas-ure that has been recently developed for the assessment of muscle spasticity. There is a dearth of research on the validity of the MMAS. The aim of the present study was to investi-gate the relationship between the MMAS and the biomechanical measure of work-velocity slope in assessing knee extensor muscle spasticity in patients with hemiparesia. Materials & Methods: Fourteen patients with post-stroke hemiparesia were included in this cross sectional study. Knee extensor spasticity was assessed with MMAS. An isokinetic dy-namometer was used to impose knee passive flexion with the angular velocity of 10, 30, 60, and 90 °/Sec to measure Torque-angle data. Work (Joule was calculated at each velocity to determine the slope of the work-velocity curves as the biomechanical measure of muscle spasticity. Results: The mean work decreased as the velocity increased but was not statistically signifi-cant (P = 0.07. The mean slope was – 0.35 [J /(°/Sec]. There was no significant correlation between the MMAS and the work-velocity slope (r =0.31, P = 0.28. Conclusion: There was no significant relationship between the MMAS and the biomechanical measure of work-velocity slope. Further studies with larger sample size are suggested. (Sci J Hamadan Univ Med Sci 2014; 21 (2: 131-136

  3. Influence of obstructive sleep apnea syndrome in the fluctuation of the submaximal isometric torque of knee extensors in patients with early-grade osteoarthritis

    Science.gov (United States)

    Silva, Andressa; Mello, Marco T.; Serrão, Paula R.; Luz, Roberta P.; Bittencourt, Lia R.; Mattiello, Stela M.

    2015-01-01

    OBJECTIVE: The aim of this study was to investigate whether obstructive sleep apnea (OSA) alters the fluctuation of submaximal isometric torque of the knee extensors in patients with early-grade osteoarthritis (OA). METHOD: The study included 60 male volunteers, aged 40 to 70 years, divided into four groups: Group 1 (G1) - Control (n=15): without OA and without OSA; Group 2 (G2) (n=15): with OA and without OSA; Group 3 (G3) (n=15): without OA and with OSA; and Group 4 (G4) (n=15) with OA and with OSA. Five patients underwent maximal isometric contractions of 10 seconds duration each, with the knee at 60° of flexion to determine peak torque at 60°. To evaluate the fluctuation of torque, 5 submaximal isometric contractions (50% of maximum peak torque) of 10 seconds each, which were calculated from the standard deviation of torque and coefficient of variation, were performed. RESULTS: Significant differences were observed between groups for maximum peak torque, while G4 showed a lower value compared with G1 (p=0.005). Additionally, for the average torque exerted, G4 showed a lower value compared to the G1 (p=0.036). However, no differences were found between the groups for the standard deviation (p=0.844) and the coefficient of variation (p=0.143). CONCLUSION: The authors concluded that OSA did not change the parameters of the fluctuation of isometric submaximal torque of knee extensors in patients with early-grade OA. PMID:26443974

  4. Influence of obstructive sleep apnea syndrome in the fluctuation of the submaximal isometric torque of knee extensors in patients with early-grade osteoarthritis

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    Andressa Silva

    2015-08-01

    Full Text Available OBJECTIVE: The aim of this study was to investigate whether obstructive sleep apnea (OSA alters the fluctuation of submaximal isometric torque of the knee extensors in patients with early-grade osteoarthritis (OA.METHOD: The study included 60 male volunteers, aged 40 to 70 years, divided into four groups: Group 1 (G1 - Control (n=15: without OA and without OSA; Group 2 (G2 (n=15: with OA and without OSA; Group 3 (G3 (n=15: without OA and with OSA; and Group 4 (G4 (n=15 with OA and with OSA. Five patients underwent maximal isometric contractions of 10 seconds duration each, with the knee at 60° of flexion to determine peak torque at 60°. To evaluate the fluctuation of torque, 5 submaximal isometric contractions (50% of maximum peak torque of 10 seconds each, which were calculated from the standard deviation of torque and coefficient of variation, were performed.RESULTS: Significant differences were observed between groups for maximum peak torque, while G4 showed a lower value compared with G1 (p=0.005. Additionally, for the average torque exerted, G4 showed a lower value compared to the G1 (p=0.036. However, no differences were found between the groups for the standard deviation (p=0.844 and the coefficient of variation (p=0.143.CONCLUSION: The authors concluded that OSA did not change the parameters of the fluctuation of isometric submaximal torque of knee extensors in patients with early-grade OA.

  5. Less indication of muscle damage in the second than initial electrical muscle stimulation bout consisting of isometric contractions of the knee extensors.

    Science.gov (United States)

    Aldayel, Abdulaziz; Jubeau, Marc; McGuigan, Michael R; Nosaka, Kazunori

    2010-03-01

    This study compared the first and second exercise bouts consisting of electrically evoked isometric contractions for muscle damage profile. Nine healthy men (31 +/- 4 years) had two electrical muscle stimulation (EMS) bouts separated by 2 weeks. The knee extensors of one leg were stimulated by biphasic rectangular pulses (75 Hz, 400 mus, on-off ratio 5-15 s) at the knee joint angle of 100 degrees (0 degrees , full extension) to induce 40 isometric contractions, while the current amplitude was increased to maintain maximal force generation. Maximal voluntary isometric contraction (MVC) torque of the knee extensors at 100 degrees , muscle soreness, pressure pain threshold and plasma creatine kinase (CK) activity were used as indirect markers of muscle damage, and measured before and 1, 24, 48, 72 and 96 h after EMS bout, and the changes over time were compared between bouts. The torque produced during exercise was approximately 30% of MVC, and no significant difference between bouts was evident for the changes in peak and average torque over 40 contractions. MVC decreased significantly (P < 0.05) by 26% immediately and 1 h after both bouts, but the recovery was significantly (P < 0.05) faster after the second bout (100% at 96 h) compared with the first bout (81% at 96 h). Development of muscle soreness and tenderness, and increases in plasma CK activity were significantly (P < 0.05) smaller after the second than the first bout. These results show that changes in muscle damage markers were attenuated in the second EMS bout compared with the initial EMS bout.

  6. Impact of external resistance and maximal effort on force-velocity characteristics of the knee extensors during strengthening exercise: a randomized controlled experiment.

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    Van Roie, Evelien; Bautmans, Ivan; Boonen, Steven; Coudyzer, Walter; Kennis, Eva; Delecluse, Christophe

    2013-04-01

    It remains controversial whether maximal effort attained by high external resistance is required to optimize muscle adaptation to strengthening exercise. Here, we compared different training protocols reaching maximal effort with either high-resistance (HImax, 80% of 1-repetition maximum [1RM]) or low-resistance (LOmax, ≤40% 1RM). Thirty-six young volunteers were randomly assigned to 9 weeks of leg extension training at either HImax (1 set of 10-12 repetitions at 80% 1RM), LO (1 set of 10-12 repetitions at 40% 1RM, no maximal effort), or LOmax (1 set of 10-12 repetitions at 40% 1RM, preceded [no rest] by 60 repetitions at 20-25% 1RM). Knee extension 1RM was measured preintervention and postintervention and before the 7th, 13th, and 19th training sessions. Preintervention and postintervention, knee extensor static (PTstat) and dynamic (PTdyn) peak torque, maximal work (MW), and speed of movement at 20% (S20), 40% (S40), and 60% (S60) of PTstat were recorded with a Biodex dynamometer. All the groups showed a significant increase in 1RM, with a greater improvement in HImax from the 13th session on (p < 0.05). The HImax was the only group that significantly increased PTstat (+7.4 ± 8.1%, p = 0.01). The LOmax showed a significantly greater increase in S20 (+6.0 ± 3.2%), PTdyn (+9.8 ± 5.6%), and MW (+15.1 ± 10.6%) than both HImax and LO (p = 0.044 for S20, p = 0.030 for PTdyn, p = 0.025 for MW) and was the only group that increased in S40 (+7.7 ± 9.7%, p = 0.032). In conclusion, significant differences between HImax and LOmax on force-velocity characteristics of the knee extensors were found, although maximal effort was achieved in both training regimens. Thus, LOmax may not be considered as a replacement for HImax but rather as an alternative with different training-specific adaptations.

  7. The susceptibility of the knee extensors to eccentric exercise-induced muscle damage is not affected by leg dominance but by exercise order.

    Science.gov (United States)

    Hody, S; Rogister, B; Leprince, P; Laglaine, T; Croisier, J-L

    2013-09-01

    The aims of this study were first to compare the response of dominant and non-dominant legs to eccentric exercise and second, to examine whether there is an effect of exercise order on the magnitude of symptoms associated with intense eccentric protocols. Eighteen young men performed three sets of 30 maximal eccentric isokinetic (60° s(-1)) contractions of the knee extensors (range of motion, ROM: 0°-100°, 0 = full extension) using either dominant or non-dominant leg. They repeated a similar eccentric bout using the contralateral leg 6 weeks later. The sequence of leg's use was allocated to create equally balanced groups. Four indirect markers of muscle damage including subjective pain intensity, maximal isometric strength, muscle stiffness and plasma creatine kinase (CK) activity were measured before and 24 h after exercise. All markers changed significantly following the eccentric bout performed either by dominant or non-dominant legs, but no significant difference was observed between legs. Interestingly, the comparison between the first and second eccentric bouts revealed that muscle soreness (-42%, Pexercise-induced muscle damage and supports for the first time the existence of a contralateral protection against exercise-induced muscle damage in the lower limbs.

  8. Correlation between the 8-repetition maximum test and isokinetic dynamometry in the measurement of muscle strength of the knee extensors: A concurrent validity study.

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    Taylor, J David; Fletcher, James P

    2013-05-01

    The 8-repetition maximum test has the potential to be a feasible, cost-effective method of measuring muscle strength for clinicians. The purpose of this study was to investigate the concurrent validity of the 8-repetition maximum test in the measurement of muscle strength by comparing the 8-repetition maximum test to the gold standard of isokinetic dynamometry. Thirty participants (15 males and 15 females, mean age = 23.2 years [standard deviation = 1.0]) underwent 8-repetition maximum testing and isokinetic dynamometry testing of the knee extensors (at 60, 120, and 240 degrees per second) on two separate sessions with 2-3 days between each mode of testing. Linear regression was used to assess the validity by comparing the findings between 8-repetition maximum testing and isokinetic dynamometry testing. Significant correlations were found between the 8-repetition maximum and isokinetic dynamometry peak torque at each testing velocity (r  =  0.71-0.85). The highest correlations were between the 8-repetition maximum and isokinetic dynamometry peak torques at 60 (r  =  0.85) and 120 (r  =  0.85) degrees per second. The findings of this study provide supportive evidence for the use of 8-repetition maximum testing as a valid, alternative method for measuring muscle strength.

  9. Can a wearable strain sensor based on a carbon nanotube network be an alternative to an isokinetic dynamometer for the measurement of knee-extensor muscle strength?

    Science.gov (United States)

    Benlikaya, Ruhan; Ege, Yavuz; Pündük, Zekine; Slobodian, Petr; Meriç, Gökhan

    2017-04-01

    This study aimed to find out whether a wearable strain sensor including thermoplastic polyurethane composite with a multi-walled carbon nanotube network could be a viable alternative to an isokinetic dynamometer for the measurement of knee-extensor muscle strength. For the first time, the voltage-torque and angle–time relations of the sensor were determined to allow a comparison between the angle-dependent torque changes of the dynamometer and the sensor. This comparison suggested that the torque–angle relations of the dynamometer and the sensor did not have the same characteristics. In this regard, the sensor may be used in the torque measurements due to the moderate correlation between the torque values determined via the isokinetic dynamometer and the sensor and due to the significant difference between low and high torque values of the sensor. By the same token, the torque-angle graph of the sensor may be more informative than that of the dynamometer in evaluation of knee problems.

  10. Effect of a high intensity quadriceps fatigue protocol on knee joint mechanics and muscle activation during gait in young adults.

    Science.gov (United States)

    Murdock, Gillian Hatfield; Hubley-Kozey, Cheryl L

    2012-02-01

    The purpose of this study was to determine the effect of impaired quadriceps function on knee joint biomechanics and neuromuscular function during gait. Surface electromyograms, three-dimensional motion and ground reaction forces were collected during gait before and after 20 healthy adults completed a high intensity quadriceps fatigue protocol. Pattern recognition techniques were utilized to examine changes in amplitude and temporal characteristics of all gait variables. The fatigue protocol resulted in decreased knee extensor torque generation and quadriceps median power frequencies for 18 of 20 participants (p gait data from these 18 participants was analyzed. The knee external rotation angle increased (p knee motion and loading characteristics were altered following a high intensity fatigue protocol in a manner that may place the knee joint at greater risk for joint pathology and injury.

  11. Effects of isokinetic eccentric training on knee extensor and flexor torque and on gait of individuals with long term ACL reconstruction: A controlled clinical trial

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    Heleodório Honorato dos Santos

    2014-12-01

    Full Text Available This study investigated the effects of the isokinetic eccentric training (IET on the knee extensor and flexor torque and kinematic gait parameters in individuals with ACL reconstruction. Sixteen men with ACL reconstructed (ACLr whose torque and the gait were evaluated, before and after 12 weeks of IET, was compared to a control group (14 individuals. Student t, MANOVA and ANOVA tests were performed with 5% of significance. The training increased the isometric, concentric at 30 and 120º/s (p < .05 and eccentric at 30º/s (p < .01 extensor torque on the affected limb (AL, and eccentric at 30 and 120º/s (p < .01, on the non-affected limb (NAL. In the flexors, there was an increase on the torque: isometric, concentric at 30º/s and eccentric at 30 and 120º/s (p < .01 in AL and in eccentric at 30 (p < .05 and 120º/s (p< .01 in NAL. With respect to the angular and spatio-temporal variables gait, there was no difference between pre-and post-training in LCAr group. Compared to control group, the cycle time, in two members, was lower in LCAr group, and stride length and cadence were higher in the AL of the LCAr (p < .05. Moreover, the knee flexion-extension angles (minimum and maximum remained lower in LCAr, pre- and post-training (p < .01. The torque gain associated with eccentric isokinetic training did not affect the kinematic parameters of gait in patients undergoing ACL reconstruction.

  12. Tennis in hot and cool conditions decreases the rapid muscle torque production capacity of the knee extensors but not of the plantar flexors

    Science.gov (United States)

    Girard, Olivier; Racinais, Sébastien; Périard, Julien D

    2014-01-01

    Objectives To assess the time course of changes in rapid muscle force/torque production capacity and neuromuscular activity of lower limb muscles in response to prolonged (∼2 h) match-play tennis under heat stress. Methods The rates of torque development (RTD) and electromyographic activity (EMG; ie, root mean square) rise were recorded from 0 to 30, –50, –100 and –200 ms during brief (3–5 s) explosive maximal isometric voluntary contractions (MVC) of the knee extensors (KE) and plantar flexors (PF), along with the peak RTD within the entirety of the torque-time curve. These values were recorded in 12 male tennis players before (prematch) and after (postmatch, 24 and 48 h) match-play in HOT (∼37°C) and COOL (∼22°C) conditions. Results The postmatch core temperature was greater in the HOT (∼39.4°C) vs COOL (∼38.7°C) condition (p<0.05). Reductions in KE RTD occurred within the 0–200 ms epoch after contraction onset postmatch and at 24 h, compared with prematch, independent of environmental conditions (p<0.05). A similar reduction in the KE peak RTD was also observed postmatch relative to prematch (p<0.05). No differences in KE RTD values were observed after normalisation to MVC torque. Furthermore, the rate of KE EMG activity rise remained unchanged. Conversely, the PF contractile RTD and rate of EMG activity rise were unaffected by the exercise or environmental conditions. Conclusions In the KE, a reduction in maximal torque production capacity following prolonged match-play tennis appears to account for the decrease in the rate of torque development, independent of environmental conditions, while remaining unchanged in the PF. PMID:24668381

  13. The correlation between isokinetic strength of knee extensors and vertical jump performance in adolescent soccer players in an annual training cycle

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    Michal Lehnert

    2013-03-01

    Full Text Available BACKGROUND: Isokinetic testing is often used to provide coaches with important information about the physical status of athletes. Therefore, a number of studies focused on the assessment of the relationship between isokinetic and functional tests including soccer. The results of a limited number of studies indicate that the relationship changes in different training periods. OBJECTIVE: The aim of the study was to determine the relationship between the characteristics of the isokinetic strength of knee extensors and vertical jump performance in three different periods of the annual training cycle in adolescent soccer players. METHODS: A group of adolescent soccer players (n = 16; average age 16.7 ± 0.7 years was tested at the end of the competitive season, at the beginning of the off-season and during the sixth week of a new competitive season. The isokinetic concentric peak torque (PT, peak power (Pmax and time to peak torque (TPT of the dominant leg and non-dominant leg were measured at angular velocities of 60°•s–1, 180°•s–1, 360°•s–1. The explosive strength of the lower extremities was measured using the countermovement jump with free arms (CMJF method and countermovement jump with the arms crossed over the chest. Based on literary reviews, a logically significant value of the correlation was set at > 0.30. RESULTS: The correlations between the isokinetic strength characteristics and vertical jump performance irrespective of the training period were low to moderate; 56% of the correlations were > 0.30. In the different periods of the annual training cycle, the occurrence of correlations > 0.30 as well as their value varied – 67% at the end of the competitive season, 31% at the beginning of the off-season and 64% at the beginning of the competitive season. For both types of jumps, the correlations for Pmax and PT parameters were the lowest during the second measurement in most cases; no trend was observed for the TPT

  14. Avaliação da altura patelar em atletas com tendinopatia crônica do aparelho extensor do joelho Evaluation of the patellar height in athletes with diagnosed with chronic tendinopathy of the knee extensor mechanism

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    Emerson Garms

    2011-01-01

    Full Text Available OBJETIVO: Avaliar radiograficamente a altura patelar de atletas com diagnóstico de tendinopatia crônica do aparelho extensor do joelho (TCAE. MÉTODOS: Na amostra foram avaliados radiograficamente 65 pacientes (110 joelhos com idade entre 15 e 40 anos e de diferentes modalidades esportivas com e sem diagnóstico de tendinopatia crônica do aparelho extensor do joelho (jumper's knee. Os atletas foram divididos em dois grupos: aqueles com diagnóstico de TCAE (grupo 1: 38 atletas - 56 joelhos e um grupo que denominamos de controle (grupo 2: 27 atletas - 54 joelhos. RESULTADOS: No grupo 1 tivemos 18 atletas que apresentavam a doença bilateralmente na ocasião dos exames. Para a medida da altura patelar utilizamos os índices radiográficos de Insall e Salvati e Blackburne e Peel. CONCLUSÃO: A presença de patela alta no grupo de atletas com tendinopatia crônica do aparelho extensor do joelho foi significante maior do que a observada no grupo controle.OBJECTIVES: To carry out a radiographic evaluation of patellar height in athletes diagnosed with chronic tendinopathy of the knee extensor mechanism; METHODS: Radiographic assessments were carried out on 65 patients (110 knees aged between 15 and 40 years, who practiced different kinds of sports, some with of chronic tendinopathy of the knee extensor mechanism (jumper's knee and others without. The athletes were divided into two groups: those with diagnosed "jumper's knee" (group 1:38 athletes - 56 knees and a control group (group 2:27 athletes - 54 knees. In group 1, 18 of the athletes presented the condition in both knees on examination. The height of the patella was measured using the Insall-Salvati and Blackburne-Peel x-ray methods. CONCLUSION: The presence of a high patella in the group of athletes with chronic tendinopathy of the knee extensor mechanism was significantly higher than in the control group.

  15. The effects of knee extensor eccentric training on functional tests in healthy subjects Os efeitos do treino isocinético excêntrico dos extensores do joelho nos testes funcionais em sujeitos saudáveis

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    Heleodório H. Santos

    2010-08-01

    Full Text Available BACKGROUND: It is well known that eccentric training increases muscle strength and promotes greater neural activation, and therefore has been used in the recovery of knee extensors. The hypothesis of this study was that there would be a strong correlation between knee extensor torque and functional tests. OBJECTIVES: To investigate the relationship between knee extensor peak torque and functional tests of agility (runs and propulsion (hop for distance after short-term isokinetic eccentric training. METHODS: Twenty healthy and active male undergraduate students (age 22.5±2.1 years; height 1.72±0.10 m; weight 67.8±9.5 kg; body mass index: 22.5±2.0 kg/m², with no abnormalities or history of injury of the limbs, performed an isokinetic assessment of the knee extensors and flexors and also functional tests before and after isokinetic training, which consisted of 3 sets of 10 MVECs at 30º/s, with 3 minutes of rest between sets, twice a week for 6 weeks. RESULTS: The eccentric training increased the extensor peak torque (16, 27 and 17%; PCONTEXTUALIZAÇÃO: Sabe-se que o treino excêntrico aumenta a força muscular, promovendo uma maior ativação neural e, portanto, tem sido usado na recuperação do torque extensor. A hipótese deste estudo foi a de que possa existir uma forte correlação entre o torque extensor do joelho e os testes funcionais. OBJETIVOS: Correlacionar o torque extensor do joelho com os testes funcionais de agilidade (corridas e impulsão (saltos em distância após o treino isocinético excêntrico de curta duração. MÉTODOS: Vinte homens universitários, ativos e saudáveis (22,5±2,1 anos; 1,72±0,10 m; 67,8±9,5 kg; IMC 22,5±2,0 kg/m², sem reportar anormalidades ou história de lesão no membro inferior, realizaram avaliação isocinética do torque extensor e flexor do joelho e testes funcionais antes e depois do treino isocinético que consistiu em três séries de 10 CEVM a 30º/s, com 3 minutos de repouso entre as

  16. Is energy expenditure taken into account in human sub-maximal jumping?--A simulation study.

    Science.gov (United States)

    Vanrenterghem, Jos; Bobbert, Maarten F; Casius, L J Richard; De Clercq, Dirk

    2008-02-01

    This paper presents a simulation study that was conducted to investigate whether the stereotyped motion pattern observed in human sub-maximal jumping can be interpreted from the perspective of energy expenditure. Human sub-maximal vertical countermovement jumps were compared to jumps simulated with a forward dynamic musculo-skeletal model. This model consisted of four interconnected rigid segments, actuated by six Hill-type muscle actuators. The only independent input of the model was the stimulation of muscles as a function of time. This input was optimized using an objective function, in which targeting a specific sub-maximal height value was combined with minimizing the amount of muscle work produced. The characteristic changes in motion pattern observed in humans jumping to different target heights were reproduced by the model. As the target height was lowered, two major changes occurred in the motion pattern. First, the countermovement amplitude was reduced; this helped to save energy because of reduced dissipation and regeneration of energy in the contractile elements. Second, the contribution of rotation of the heavy proximal segments of the lower limbs to the vertical velocity of the centre of gravity at take-off was less; this helped to save energy because of reduced ineffective rotational energies at take-off. The simulations also revealed that, with the observed movement adaptations, muscle work was reduced through improved relative use of the muscle's elastic properties in sub-maximal jumping. According to the results of the simulations, the stereotyped motion pattern observed in sub-maximal jumping is consistent with the idea that in sub-maximal jumping, subjects are trying to achieve the targeted jump height with minimal energy expenditure.

  17. Estudo epidemiológico das rupturas tendinosas do mecanismo extensor do joelho em um hospital de nível I Epidemiological study on tendon ruptures of the knee extensor mechanism at a level 1 hospital

    Directory of Open Access Journals (Sweden)

    Rodrigo Pires e Albuquerque

    2012-01-01

    Full Text Available OBJETIVOS: O propósito do presente estudo é revisar aspectos epidemiológicos das rupturas tendinosas do aparelho extensor do joelho em hospital de nível I. MÉTODOS: Analisamos, retrospectivamente, 76 lesões do mecanismo extensor do joelho, tratadas cirurgicamente no Hospital Municipal Miguel Couto, no período de março de 2004 a março de 2011. Levamos em consideração idade, sexo, mecanismo de trauma, classificação anatômica da lesão, lado acometido, comorbidades e lesões associadas. RESULTADOS: Dos pacientes estudados, 68 eram do sexo masculino, com idade média de 36 anos. Quanto ao mecanismo de trauma, 62 foram por trauma direto, 21 casos foram do lado direito, oito apresentavam comorbidades e quatro tiveram lesões associadas. CONCLUSÕES: A maioria dos pacientes foi do sexo masculino, na faixa etária economicamente ativa (jovens, e vítima de trauma direto, sendo as rupturas do ligamento patelar as lesões mais comuns. Lesões associadas são raras, e as comorbidades foram pouco frequentes em nossa casuística.OBJECTIVES: The purpose of the present study was to review the epidemiological aspects of tendon ruptures of the knee extensor apparatus at a level 1 hospital. METHODS: We retrospectively ana lyzed 76 lesions of the knee extensor apparatus that were treated surgically at the Miguel Couto Municipal Hospital between March 2004 and March 2011. We took into consideration age, sex, trauma mechanism, anatomical classification of the lesion, affected side, comorbidities and associated lesions. RESULTS: Among the patients studied, 68 were male and the mean age was 36 years. Regarding the trauma mechanism, 62 lesions occurred due to direct trauma; the right side was affected in 21 cases; eight presented comor bidities and four presented associated lesions. CONCLUSION: The majority of the patients were male, at an economically active age (young people, and were victims of direct trauma. Ruptures of the patellar ligament were the

  18. Force depression following muscle shortening in sub-maximal voluntary contractions of human adductor pollicis.

    Science.gov (United States)

    Rousanoglou, Elissavet N; Oskouei, Ali E; Herzog, Walter

    2007-01-01

    Mechanical properties of skeletal muscles are often studied for controlled, electrically induced, maximal, or supra-maximal contractions. However, many mechanical properties, such as the force-length relationship and force enhancement following active muscle stretching, are quite different for maximal and sub-maximal, or electrically induced and voluntary contractions. Force depression, the loss of force observed following active muscle shortening, has been observed and is well documented for electrically induced and maximal voluntary contractions. Since sub-maximal voluntary contractions are arguably the most important for everyday movement analysis and for biomechanical models of skeletal muscle function, it is important to study force depression properties under these conditions. Therefore, the purpose of this study was to examine force depression following sub-maximal, voluntary contractions. Sets of isometric reference and isometric-shortening-isometric test contractions at 30% of maximal voluntary effort were performed with the adductor pollicis muscle. All reference and test contractions were executed by controlling force or activation using a feedback system. Test contractions included adductor pollicis shortening over 10 degrees, 20 degrees, and 30 degrees of thumb adduction. Force depression was assessed by comparing the steady-state isometric forces (activation control) or average electromyograms (EMGs) (force control) following active muscle shortening with those obtained in the corresponding isometric reference contractions. Force was decreased by 20% and average EMG was increased by 18% in the shortening test contractions compared to the isometric reference contractions. Furthermore, force depression was increased with increasing shortening amplitudes, and the relative magnitudes of force depression were similar to those found in electrically stimulated and maximal contractions. We conclude from these results that force depression occurs in sub-maximal

  19. The Effect of Acute Sub-Maximal Endurance Exercise on Serum Angiogenic Indices in Sedentary Men

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    Kamal Ranjbar

    2014-06-01

    Full Text Available Background: Endurance training increases capillary density of skeletal muscle, but the molecular mechanism of this process is not yet clear. Therefore, the purpose of this study was to investigate the effect of acute sub maximal endurance exercise on serum levels of vascular endothelial growth factor (VEGF and matrix metaloproteinases 2 and 9 (MMP-2 and MMP-9 in sedentary men. Materials and Methods: Twelve healthy men (22.37±2.30 years, BMI=23.16 ±2.61 kg/mP 2 P participated in this study. Subjects exercised for 1h at 70% of VOR2R max, 3 days after the VOR2R max determination. Antecubital vein blood was collected at rest, immediately and 2h after the exercise. Serum VEGF, MMP-2 and MMP-9 were measured by ELISA methods5T. Results: Serum levels of VEGF and MMP-2 decreased immediately after the exercise. 2 hours after the exercise, serum levels of VEGF remained at a lower level but serum MMP-2 returned to its basal level. Also, serum levels of MMP-9 did not change significantly in response to exercise5T. Conclusion: Acute sub-maximal endurance exercise decreased the main factors involved in development of capillary density in sedentary men. This might to due to the fact that, sub maximal exercise could not provide the two main stimulating factors of angiogenesis, i.e. Shear stress and hypoxia. It could also be explained by the fact that the mechanism of development of capillary network following regular endurance training is different from that following an acute exercise5T.5T

  20. [Sub-maximal aerobic capacity and quality of life of patients with rheumatoid arthritis].

    Science.gov (United States)

    Lataoui, S; Belghali, S; Zeglaoui, H; Bouajina, E; Ben Saad, H

    2017-01-01

    Studies about sub-maximal aerobic capacity of patients with rheumatoid arthritis are scarce. To assess the sub-maximal aerobic capacity of these patients through the 6-min walk test, estimated age of the "muscular and cardiorespiratory" chain. Thirty-seven consecutive patients (aged 20 to 60 years) with newly diagnosed rheumatoid arthritis will be included. Non-inclusion criteria will be: use of drugs (e.g.; methotrexate, beta-blockers), orthopaedic or rheumatologic conditions (other than rheumatoid arthritis) that may alter walking ability and recent infections. Exclusion criteria will be: 6-min walking test contra-indications and imperfect performance of the required lung function and walking maneuvers. Signs of walking intolerance will be: test interruption, distance ≤lower limit of normal, dyspnea score ≥5/10 (visual analogue scale) at the end of the test, haemoglobin oxygen saturation (SpO2) drop ≥5%, cardiac frequency at the end of the test ≤60% of maximum predicted. An estimated "muscular and cardiorespiratory chain" age higher than the chronological one will be considered as a sign of accelerated ageing. A high percentage of patients suffering from rheumatoid arthritis would show evidences of walking limitation and accelerated "muscular and cardiorespiratory chain" ageing. There would be a significant correlation between the walking test and clinical, biological, radiological and pulmonary function data and the patients' quality-of-life status. Copyright © 2016 SPLF. Published by Elsevier Masson SAS. All rights reserved.

  1. Effect of energy expenditure and training status on leptin response to sub-maximal cycling.

    Science.gov (United States)

    Bouassida, Anissa; Chatard, Jean-Claude; Chamari, Karim; Zaouali, Monia; Feki, Youssef; Gharbi, Najoua; Zbidi, Abdelkarim; Tabka, Zouhaïr

    2009-01-01

    We examined the leptin response and related hormones during and after two sub-maximal exercise protocols in trained and untrained subjects. During this study, plasma concentrations of leptin [Lep], insulin [I], cortisol [C], growth hormone [GH], glucose [G] and lactate [La] were measured. 7 elite volleyball trained players (TR) and 7 untrained (UTR) subjects (percent body fat: 13.2 ± 1.8 versus 15.7 ± 1.0, p < 0.01, respectively) were examined after short and prolonged sub-maximal cycling exercise protocols (SP and PP). Venous blood samples were collected before each protocol, during, at the end, and after 2 and 24 h of recovery. SP and PP energy expenditures ranged from 470 ± 60 to 740 ± 90 kcal for TR and from 450 ± 60 to 710 ± 90 kcal for UTR, respectively. [Lep] was related to body fat percentage and body fat mass in TR (r = 0. 84, p < 0.05 and r = 0.93, p < 0.01) and in UTR (r = 0.89, p < 0.01 and r = 0.92, p < 0. 01, respectively). [Lep] did not change significantly during both protocols for both groups but was lower (p < 0.05) in all sampling in TR when compared to UTR. Plasma [I] decreased (p < 0.01) and [GH] increased (p < 0.01) significantly during both SP and PP and these hormones remained lower (I: p < 0.01) and higher (GH: p < 0.01) than pre-exercise levels after a 2-h recovery period, returning to base-line at 24-h recovery. Plasma [La] increased (p < 0.01) during both protocols for TR and UTR. There was no significant change in [C] and [G] during and after both protocols for all subjects. It is concluded that 1) leptin is not sensitive to acute short or prolonged sub-maximal exercises (with energy expenditure under 800 kcal) in volleyball/ anaerobically trained athletes as in untrained subjects, 2) volleyball athletes showed significantly lower resting and exercise leptin response with respect to untrained subjects and 3) it appears that in these anaerobically trained athletes leptin response to exercise is more sensitive to the level of energy

  2. EFFECT OF ENERGY EXPENDITURE AND TRAINING STATUS ON LEPTIN RESPONSE TO SUB-MAXIMAL CYCLING

    Directory of Open Access Journals (Sweden)

    Anissa Bouassida

    2009-06-01

    Full Text Available We examined the leptin response and related hormones during and after two sub-maximal exercise protocols in trained and untrained subjects. During this study, plasma concentrations of leptin [Lep], insulin [I], cortisol [C], growth hormone [GH], glucose [G] and lactate [La] were measured. 7 elite volleyball trained players (TR and 7 untrained (UTR subjects (percent body fat: 13.2 ± 1.8 versus 15.7 ± 1.0, p < 0.01, respectively were examined after short and prolonged sub-maximal cycling exercise protocols (SP and PP. Venous blood samples were collected before each protocol, during, at the end, and after 2 and 24 h of recovery. SP and PP energy expenditures ranged from 470 ± 60 to 740 ± 90 kcal for TR and from 450 ± 60 to 710 ± 90 kcal for UTR, respectively. [Lep] was related to body fat percentage and body fat mass in TR (r = 0. 84, p < 0.05 and r = 0.93, p < 0.01 and in UTR (r = 0.89, p < 0.01 and r = 0.92, p < 0. 01, respectively. [Lep] did not change significantly during both protocols for both groups but was lower (p < 0.05 in all sampling in TR when compared to UTR. Plasma [I] decreased (p < 0.01 and [GH] increased (p < 0.01 significantly during both SP and PP and these hormones remained lower (I: p < 0.01 and higher (GH: p < 0.01 than pre-exercise levels after a 2-h recovery period, returning to base-line at 24-h recovery. Plasma [La] increased (p < 0.01 during both protocols for TR and UTR. There was no significant change in [C] and [G] during and after both protocols for all subjects. It is concluded that 1 leptin is not sensitive to acute short or prolonged sub-maximal exercises (with energy expenditure under 800 kcal in volleyball/ anaerobically trained athletes as in untrained subjects, 2 volleyball athletes showed significantly lower resting and exercise leptin response with respect to untrained subjects and 3 it appears that in these anaerobically trained athletes leptin response to exercise is more sensitive to the level of

  3. Imaging of postoperative knee extensor mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Motamedi, Kambiz [David Geffen School of Medicine at UCLA, Musculoskeletal Imaging-Department of Radiology, 200 Medical Plaza, Suite 165-59, Los Angeles, CA 90095 (United States); Seeger, Leanne L. [David Geffen School of Medicine at UCLA, Musculoskeletal Imaging-Department of Radiology, 200 Medical Plaza, Suite 165-57, Los Angeles, CA 90095 (United States); Hame, Sharon L. [David Geffen School of Medicine at UCLA, Department of Orthopedic Surgery, Box 956902, 76-143 CHS, Los Angeles, CA 90095 (United States)

    2005-05-01

    Disorders of the anterior knee are common and include patellofemoral syndrome, patella instability, patella fracture, and patellar and quadriceps tendon ruptures. Depending on the operative procedure performed, the post-operative imaging appearance of these knees may be confusing. It is crucial for the radiologist to be familiar with the procedures performed in order to recognize the postoperative findings. Radiologists must be able to interpret hardware (anchors, screw and wires) and disruptions in soft tissue planes that may persist with these types of procedures.

  4. Effects of different methods of antagonist muscles pre-activation on knee extensors neuromuscular responses Efeitos da ordem de pré-ativação dos músculos antagonistas nas respostas neuromusculares dos extensores do joelho

    Directory of Open Access Journals (Sweden)

    Rodrigo L. Carregaro

    2011-12-01

    Full Text Available BACKGROUND: Pre-activation of antagonistic muscles is used in different modalities of exercise and neuromuscular rehabilitation protocols, but its effectiveness is still controversial. OBJECTIVE: To verify the impact of two different methods of pre-activation of knee antagonist muscles in the neuromuscular performance and electromyographic activity of knee extensors. METHODS: Fifteen healthy men (23.9±4.2 years of age, 1.78±0.08 meters and 81.4±10.7 kg performed, on different days, two protocols of isokinetic muscle contraction with 4 sets of 10 repetitions at 60°.s-1 and 1 minute between sets: (1 Reciprocal Contraction (RC: reciprocal concentric exercise of agonist/antagonist muscles (knee flexion [KF] immediately followed by knee extension [KE] and (2 Superset (SS: alternated concentric exercise of agonist/antagonist muscles (KF set followed by a set of KE. A repeated measures ANOVA with least-significant difference post-hoc test was used to detect differences between protocols. RESULTS: There were no significant differences between protocols (p>0.05 for peak torque (PT and total work (Tw. On the SS protocol there was a significant decrease in Tw on the last two sets (pCONTEXTUALIZAÇÃO: A pré-ativação de músculos antagonistas é utilizada em diferentes modalidades de exercício e em diferentes protocolos de reabilitação neuromuscular, porém suas respostas ainda são controversas. OBJETIVO: Verificar o impacto de duas diferentes estratégias de pré-ativação de músculos antagonistas no desempenho neuromuscular e na atividade eletromiográfica dos extensores do joelho. MÉTODOS: Quinze homens sadios (23,9±4,2 anos; 1,78±0,08 m e 81,4±10,7 kg realizaram, em dias distintos, dois protocolos de ações musculares isocinéticas com quatro séries de dez repetições a 60°.s-1 e intervalo de 1 minuto entre séries: 1 contração recíproca (CR: exercício concêntrico recíproco de antagonistas/agonistas (uma repetição de flex

  5. Effects of the training status on the hormonal response and recovery from high-intensity isokinetic exercise: comparisons between endurance-trained athletes and sedentary subjects.

    Science.gov (United States)

    Minetto, M A; Paccotti, P; Borrione, P; Massazza, G; Ventura, M; Termine, A; Di Luigi, L; Pigozzi, F; Angeli, A

    2006-09-01

    Aims of the study were: to determine the differences in the mechanical, hormonal and lactate responses to a high-intensity isokinetic exercise in two groups of endurance-trained athletes (EA, n = 11) and sedentary subjects (SED, n = 11); to evaluate the relationships between the hormonal and lactate responses; to evaluate the effects of the training status on the pituitary responsiveness to the exercise. EA and SED completed, for each leg, 4 sets of 20 maximal concentric contractions of the knee extensor muscle groups at 180 degrees s-1 angular velocity. Blood and saliva for hormonal and lactate determinations were sampled before, immediately after the test and during the subsequent recovery of 2 hours. The exercise was completed by all subjects and elicited significant mechanical and biochemical responses both in EA and in SED subjects. No differences were found between the two groups both in the mechanical performances and in the increases of lactate and hormones of the pituitary-adrenal axis or in the comparison of the slopes of adrenocorticotropic hormone (ACTH), cortisol, and dehydroepiandrosterone recovery after the peak. The correlation analyses showed significant positive relationships between lactate peak values and percentages of change for ACTH (r2 = 0.16, P training status on the pituitary responsiveness to exercise was evident, as it was indirectly confirmed by no abnormalities in the rates of hormonal recovery after the exercise session.

  6. LHC Report: reaching high intensity

    CERN Multimedia

    Jan Uythoven

    2015-01-01

    After both beams having been ramped to their full energy of 6.5 TeV, the last two weeks saw the beam commissioning process advancing on many fronts. An important milestone was achieved when operators succeeded in circulating a nominal-intensity bunch. During the operation, some sudden beam losses resulted in beam dumps at top energy, a problem that needed to be understood and resolved.   In 2015 the LHC will be circulating around 2800 bunches in each beam and each bunch will contain just over 1 x 1011 protons. Until a few days ago commissioning was taking place with single bunches of 5 x 109 protons. The first nominal bunch with an intensity of 1 x 1011 protons was injected on Tuesday, 21 April. In order to circulate such a high-intensity bunch safely, the whole protection system must be working correctly: collimators, which protect the aperture, are set at preliminary values known as coarse settings; all kicker magnets for injecting and extracting the beams are commissioned with beam an...

  7. Isokinetic training for knee extensor and flexor after partial denervation or hemiplegia%神经功能异常屈伸膝肌的等速运动训练

    Institute of Scientific and Technical Information of China (English)

    郑光新; 邹毅; 瞿玮

    2001-01-01

    Objective To study the effect of isokinetic training on knee extensor and flexor with nerve function abnormality caused by partial denervation or hemiplegia.Methods Both knees of 16 cases with nerve function abnormality and 16 cases with traumatic osteoarthropathy were evaluated by Cybex 300(60°/s) before and after isokinetic training.The angular velocity began at 60°/s,90°/s,120°/s,150°/s to 180°/s,from here the velocity was gradually descended to 60°/s.Each speed repeated 10 times.Before and after training,peak torque-flexor(PT-F),peak torque-extensor(PT-E),F/Q ratio and difference in % of involved knees were recorded.The change rate of mean muscle strength per week was calculated.The design method was repeatedly measured using analysis of variance to compare the difference in both groups.Results After training:1.The PT-F and PT-E were enhanced.The change rate of PT-F and PT-E in involved knees per week was greater than that of uninvolved knees,but that of abnormal nerve group was obviously lower than that of the control group(PT-F:F=8.82,P<0.01;PT-E:F=4.99,P<0.05).2.The difference in % of PT-F and PT-E in involved knees all was decreased,the reducing amplitude in abnormal nerve group was respectively 3.7% and 4.4% vs. the 11.0% and 13.4% of control group.The difference in % of PT-F and PT-E in control group after training was markedly lower than before(PT-F:F=6.40,P<0.01;PT-E:F=22.69,P<0.01).3.F/Q ratio all was significantly decreased in two groups,but there wasn't obvious difference(F=0.95,P>0.05).Conclusion The study suggests that isokinetic training can improve the muscle strength of nerve function abnormality and stabilize the knee joints in partial denervation and hemiplegia.%目的 了解常用等速肌力训练方案对伴神经异常性屈、伸膝肌力的影响。方法 伴神经异常和单纯骨关节伤病后的患者各16例,用Cybex330型等速运动仪评定(60°/s)双侧膝关节,用60°/s~180

  8. Creatine supplementation spares muscle glycogen during high intensity intermittent exercise in rats

    Directory of Open Access Journals (Sweden)

    Costa André

    2010-01-01

    Full Text Available Abstract Background The effects of creatine (CR supplementation on glycogen content are still debatable. Thus, due to the current lack of clarity, we investigated the effects of CR supplementation on muscle glycogen content after high intensity intermittent exercise in rats. Methods First, the animals were submitted to a high intensity intermittent maximal swimming exercise protocol to ensure that CR-supplementation was able to delay fatigue (experiment 1. Then, the CR-mediated glycogen sparing effect was examined using a high intensity intermittent sub-maximal exercise test (fixed number of bouts; six bouts of 30-second duration interspersed by two-minute rest interval (experiment 2. For both experiments, male Wistar rats were given either CR supplementation or placebo (Pl for 5 days. Results As expected, CR-supplemented animals were able to exercise for a significant higher number of bouts than Pl. Experiment 2 revealed a higher gastrocnemius glycogen content for the CR vs. the Pl group (33.59%. Additionally, CR animals presented lower blood lactate concentrations throughout the intermittent exercise bouts compared to Pl. No difference was found between groups in soleus glycogen content. Conclusion The major finding of this study is that CR supplementation was able to spare muscle glycogen during a high intensity intermittent exercise in rats.

  9. Stretching Effects: High-intensity & Moderate-duration vs. Low-intensity & Long-duration.

    Science.gov (United States)

    Freitas, S R; Vaz, J R; Bruno, P M; Andrade, R; Mil-Homens, P

    2016-03-01

    This study examined whether a high-intensity, moderate-duration bout of stretching would produce the same acute effects as a low-intensity, long-duration bout of stretching. 17 volunteers performed 2 knee-flexor stretching protocols: a high-intensity stretch (i. e., 100% of maximum tolerable passive torque) with a moderate duration (243.5 ± 69.5-s); and a low-intensity stretch (50% of tolerable passive torque) with a long duration (900-s). Passive torque at a given sub-maximal angle, peak passive torque, maximal range of motion (ROM), and muscle activity were assessed before and after each stretching protocol (at intervals of 1, 30 and 60 min). The maximal ROM and tolerable passive torque increased for all time points following the high-intensity stretching (p0.05). 1 min post-stretching, the passive torque decreased in both protocols, but to a greater extent in the low-intensity protocol. 30 min post-test, torque returned to baseline for the low-intensity protocol and had increased above the baseline for the high-intensity stretches. The following can be concluded: 1) High-intensity stretching increases the maximal ROM and peak passive torque compared to low-intensity stretching; 2) low-intensity, long-duration stretching is the best way to acutely decrease passive torque; and 3) high-intensity, moderate-duration stretching increases passive torque above the baseline 30 min after stretching. © Georg Thieme Verlag KG Stuttgart · New York.

  10. Knee extensor torque of men with early degrees of osteoarthritis is associated with pain, stiffness and function Homens com graus iniciais de osteoartrite apresentam correlação entre torque extensor do joelho e dor, rigidez e função

    Directory of Open Access Journals (Sweden)

    Paula R. M. S. Serrão

    2012-08-01

    Full Text Available BACKGROUND: Osteoarthritis (OA is a chronic-degenerative disease. The knee is the most commonly affected joint and the symptoms are generally attributed to quadriceps muscle weakness. However, few studies have evaluated this relationship in a population with early stages of knee OA. OBJECTIVE: To investigate whether a correlation among the knee extensor torque and the three subscales of the WOMAC questionnaire in men with early stages of knee OA exists. METHOD: Twenty-one men with knee OA grades I or II (according to Kellgren and Lawrence criteria participated in this study. The concentric and eccentric knee extensor torque were assessed using a Biodex System 3 Pro® isokinetic dynamometer, at a speed of 90º/s. Self-reported symptoms and disability were assessed using the WOMAC questionnaire. Spearman's correlation coefficient was used to test the relationship between the dependent variables (three subscales of WOMAC questionnaire and the independent variables (average knee extensor peak torque. RESULTS: We found a strong negative correlation between the concentric extensor torque and pain (r=-0.7, pCONTEXTUALIZAÇÃO: A osteoartrite (OA é uma doença crônico-degenerativa. O joelho é a articulação mais afetada, e os sintomas geralmente são atribuídos à fraqueza do músculo quadríceps. Entretanto, poucos estudos têm avaliado essa relação em indivíduos com graus iniciais de OA. OBJETIVO: Verificar se existe correlação entre o torque extensor do joelho e as seções dor, rigidez e função física do questionário WOMAC de homens com OA de joelho nos graus iniciais. MÉTODO: Participaram deste estudo 21 homens com OA de joelho graus I ou II (segundo critérios de Kelgren e Lawrence. Foi avaliado o torque extensor concêntrico e o excêntrico do joelho por meio do dinamômetro isocinético (Biodex System 3 Pro®, na velocidade de 90º/s. O autorrelato de sintomas e incapacidades foi avaliado por meio do questionário WOMAC. O

  11. High-intensity training in football.

    Science.gov (United States)

    Iaia, F Marcello; Rampinini, Ermanno; Bangsbo, Jens

    2009-09-01

    This article reviews the major physiological and performance effects of aerobic high-intensity and speed-endurance training in football, and provides insight on implementation of individual game-related physical training. Analysis and physiological measurements have revealed that modern football is highly energetically demanding, and the ability to perform repeated high-intensity work is of importance for the players. Furthermore, the most successful teams perform more high-intensity activities during a game when in possession of the ball. Hence, footballers need a high fitness level to cope with the physical demands of the game. Studies on football players have shown that 8 to 12 wk of aerobic high-intensity running training (> 85% HR(max)) leads to VO2(max) enhancement (5% to 11%), increased running economy (3% to 7%), and lower blood lactate accumulation during submaximal exercise, as well as improvements in the yo-yo intermittent recovery (YYIR) test performance (13%). Similar adaptations are observed when performing aerobic high-intensity training with small-sided games. Speed-endurance training has a positive effect on football-specific endurance, as shown by the marked improvements in the YYIR test (22% to 28%) and the ability to perform repeated sprints (approximately 2%). In conclusion, both aerobic and speed-endurance training can be used during the season to improve high-intensity intermittent exercise performance. The type and amount of training should be game related and specific to the technical, tactical, and physical demands imposed on each player.

  12. Restrictions in systemic and locomotor skeletal muscle perfusion, oxygen supply and VO2 during high-intensity whole-body exercise in humans

    DEFF Research Database (Denmark)

    Mortensen, S.P.; Damsgaard, R.; Dawson, E.A.

    2008-01-01

    supramaximal cycling (498 +/- 16 W; 110% of peak power; mean +/- S.E.M.) in addition to both incremental cycling and knee-extensor exercise to exhaustion in 13 trained males. During supramaximal cycling, cardiac output (Q), leg blood flow (LBF), and systemic and leg O(2) delivery and reached peak values after...... 60-90 s and thereafter levelled off at values similar to or approximately 6% (P cycling, while upper body blood flow remained unchanged (approximately 5.5 l min(-1)). In contrast, Q and LBF increased linearly until exhaustion during one-legged knee-extensor exercise accompanying...... increases in non-locomotor tissue blood flow to approximately 12 l min(-1). At exhaustion during cycling compared to knee-extensor exercise, Q, LBF, leg vascular conductance, leg O(2) delivery and leg for a given power were reduced by 32-47% (P

  13. High Intensity Secondary Beams Driven by Protons

    CERN Document Server

    Galambos, John; Nagaitsev, Sergei

    2013-01-01

    As part of the Intensity Frontier effort within the 2013 Community Summer Study, a workshop on the proton machine capabilities was held (High Intensity Secondary Beams Driven by Proton Beams) April 17-20, 2013 at Brookhaven National Laboratory in Upton, NY. Primary aims of the workshop were to understand: 1) the beam requirements for proposed high intensity proton beam based measurements; 2) the capabilities of existing world-wide high power proton machines; 3) proton facility upgrade plans and proposals for new facilities; 4) and to document the R&D needs for proton accelerators and target systems needed to support proposed intensity frontier measurements. These questions are addressed in this summary.

  14. High Intensity Interval Training: New Insights

    Institute of Scientific and Technical Information of China (English)

    Martin J.Gibala

    2008-01-01

    @@ KEY POINTS ·High-intensity interval training(HIT)is characterized by repeated sessions of relatively brief,intermittent exercise.often performed with an“a11 out”effort or at an intensity close to that which elicits peak oxygen uptake(i.e.,≥90%of VO2 peak).

  15. High-intensity, focused ultrasonic fields

    DEFF Research Database (Denmark)

    Jensen, Leif Bjørnø

    1988-01-01

    distribution, etc. involving nonlinearity, diffraction, and absorption in the high-intensity focused ultrasonic fields produced by an ellipsoid as well as a spherical cap focusing geometry. Data from the development of an ESWL of the piezoelectric disk type are reported including demands to transducers...

  16. High Intensity Exercise in Multiple Sclerosis

    DEFF Research Database (Denmark)

    Wens, Inez; Dalgas, Ulrik; Vandenabeele, Frank

    2015-01-01

    Introduction Low-to-moderate intensity exercise improves muscle contractile properties and endurance capacity in multiple sclerosis (MS). The impact of high intensity exercise remains unknown. Methods Thirty-four MS patients were randomized into a sedentary control group (SED, n = 11) and 2...

  17. The high intensity neutron source FRANZ

    CERN Document Server

    Lederer, Claudia

    2014-01-01

    The Frankfurt neutron source of Stern Gerlach Zentrum FRANZ is currently under construction at the University of Frankfurt. At FRANZ, a high intensity neutron beam in the keV energy region will be produced by bombarding a $^7$Li target with a proton beam of several mA. These unprecedented high neutron fluxes will allow a number of neutron induced cross section measurements for the first time. Measurements can be performed by the time-of-flight and by the activation technique.

  18. Cryogenic semiconductor high-intensity radiation monitors

    CERN Document Server

    Palmieri, V G; Borer, K; Casagrande, L; Da Vià, C; Devine, S R H; Dezillie, B; Esposito, A; Granata, V; Hauler, F; Jungermann, L; Li, Z; Lourenço, C; Niinikoski, T O; O'Shea, V

    2003-01-01

    This paper describes a novel technique to monitor high-intensity particle beams by means of a semiconductor detector. It consists of cooling a semiconductor detector down to cryogenic temperature to suppress the thermally generated leakage current and to precisely measure the integrated ionization signal. It will be shown that such a device provides very good linearity and a dynamic range wider than is possible with existing techniques. Moreover, thanks to the Lazarus effect, extreme radiation hardness can be achieved providing in turn absolute intensity measurements against precise calibration of the device at low beam flux.

  19. Cross-talk in mechanomyographic signals from the forearm muscles during sub-maximal to maximal isometric grip force.

    Directory of Open Access Journals (Sweden)

    Md Anamul Islam

    Full Text Available PURPOSE: This study aimed: i to examine the relationship between the magnitude of cross-talk in mechanomyographic (MMG signals generated by the extensor digitorum (ED, extensor carpi ulnaris (ECU, and flexor carpi ulnaris (FCU muscles with the sub-maximal to maximal isometric grip force, and with the anthropometric parameters of the forearm, and ii to quantify the distribution of the cross-talk in the MMG signal to determine if it appears due to the signal component of intramuscular pressure waves produced by the muscle fibers geometrical changes or due to the limb tremor. METHODS: Twenty, right-handed healthy men (mean ± SD: age  = 26.7±3.83 y; height  = 174.47±6.3 cm; mass  = 72.79±14.36 kg performed isometric muscle actions in 20% increment from 20% to 100% of the maximum voluntary isometric contraction (MVIC. During each muscle action, MMG signals generated by each muscle were detected using three separate accelerometers. The peak cross-correlations were used to quantify the cross-talk between two muscles. RESULTS: The magnitude of cross-talk in the MMG signals among the muscle groups ranged from, R2(x, y = 2.45-62.28%. Linear regression analysis showed that the magnitude of cross-talk increased linearly (r2 = 0.857-0.90 with the levels of grip force for all the muscle groups. The amount of cross-talk showed weak positive and negative correlations (r2 = 0.016-0.216 with the circumference and length of the forearm respectively, between the muscles at 100% MVIC. The cross-talk values significantly differed among the MMG signals due to: limb tremor (MMGTF, slow firing motor unit fibers (MMGSF and fast firing motor unit fibers (MMGFF between the muscles at 100% MVIC (p<0.05, η2 = 0.47-0.80. SIGNIFICANCE: The results of this study may be used to improve our understanding of the mechanics of the forearm muscles during different levels of the grip force.

  20. Effects of recovery modes after knee extensor muscles eccentric contractions

    National Research Council Canada - National Science Library

    Martin, Vincent; Millet, Guillaume Y; Lattier, Grégory; Perrod, Loïc

    2004-01-01

    ...) to hasten the recovery process from eccentric-contraction-induced injury. Before and 30 min, 24 h, 48 h, and 96 h after a one-legged downhill run, electrical stimulations were applied to the femoral nerve of healthy volunteers...

  1. A rare knee extensor mechanism injury: Vastus intermedius tendon rupture

    Directory of Open Access Journals (Sweden)

    Engin Cetinkaya

    2015-01-01

    Conclusion: We report the first case of isolated rupture of the vastus intermedius tendon in the literature and we claim that disorder may be succesfully treated with conservative treatment and adequate physiotheraphy.

  2. Myoelectric fatigue profiles of three knee extensor muscles.

    Science.gov (United States)

    Botter, A; Lanfranco, F; Merletti, R; Minetto, M A

    2009-06-01

    Aims of the present study were to: 1) investigate the differences between the myoelectric fatigue profiles of the vasti muscles of the quadriceps during electrically evoked contractions; 2) compare the myoelectric fatigue profiles of the vasti muscles between sedentary subjects and rowers; 3) analyze motor unit activation order during stimulation of the vasti muscles. In nine sedentary subjects and nine rowers surface EMG signals were detected during electrically elicited contractions of the following three muscles: vastus medialis obliquus (VMO), vastus lateralis (VL), and vastus medialis longus (VML). M-waves were recorded as the muscles were stimulated with both variable (increasing-decreasing) and constant stimulation intensities. Changes in M-wave conduction velocity (CV) during trains with non-constant current were adopted for the study of the motor unit recruitment order. Rates of change of myoelectric signal variables were adopted to assess myoelectric manifestations of fatigue during stimulation trains with constant current. We found that: 1) VL muscle was more fatigable than vastus medialis muscles; 2) VL and VML muscles of rowers resulted less fatigable than sedentary subjects; and 3) in the three muscles, motor units tended to be recruited in order of increasing CV and derecruited in order of decreasing CV with increasing/decreasing stimulation current.

  3. High intensity neutrino oscillation facilities in Europe

    CERN Document Server

    Edgecock, T R; Davenne, T; Densham, C; Fitton, M; Kelliher, D; Loveridge, P; Machida, S; Prior, C; Rogers, C; Rooney, M; Thomason, J; Wilcox, D; Wildner, E; Efthymiopoulos, I; Garoby, R; Gilardoni, S; Hansen, C; Benedetto, E; Jensen, E; Kosmicki, A; Martini, M; Osborne, J; Prior, G; Stora, T; Melo-Mendonca, T; Vlachoudis, V; Waaijer, C; Cupial, P; Chancé, A; Longhin, A; Payet, J; Zito, M; Baussan, E; Bobeth, C; Bouquerel, E; Dracos, M; Gaudiot, G; Lepers, B; Osswald, F; Poussot, P; Vassilopoulos, N; Wurtz, J; Zeter, V; Bielski, J; Kozien, M; Lacny, L; Skoczen, B; Szybinski, B; Ustrycka, A; Wroblewski, A; Marie-Jeanne, M; Balint, P; Fourel, C; Giraud, J; Jacob, J; Lamy, T; Latrasse, L; Sortais, P; Thuillier, T; Mitrofanov, S; Loiselet, M; Keutgen, Th; Delbar, Th; Debray, F; Trophine, C; Veys, S; Daversin, C; Zorin, V; Izotov, I; Skalyga, V; Burt, G; Dexter, A C; Kravchuk, V L; Marchi, T; Cinausero, M; Gramegna, F; De Angelis, G; Prete, G; Collazuol, G; Laveder, M; Mazzocco, M; Mezzetto, M; Signorini, C; Vardaci, E; Di Nitto, A; Brondi, A; La Rana, G; Migliozzi, P; Moro, R; Palladino, V; Gelli, N; Berkovits, D; Hass, M; Hirsh, T Y; Schaumann, M; Stahl, A; Wehner, J; Bross, A; Kopp, J; Neuffer, D; Wands, R; Bayes, R; Laing, A; Soler, P; Agarwalla, S K; Villanueva, A Cervera; Donini, A; Ghosh, T; Cadenas, J J Gómez; Hernández, P; Martín-Albo, J; Mena, O; Burguet-Castell, J; Agostino, L; Buizza-Avanzini, M; Marafini, M; Patzak, T; Tonazzo, A; Duchesneau, D; Mosca, L; Bogomilov, M; Karadzhov, Y; Matev, R; Tsenov, R; Akhmedov, E; Blennow, M; Lindner, M; Schwetz, T; Martinez, E Fernández; Maltoni, M; Menéndez, J; Giunti, C; García, M C González; Salvado, J; Coloma, P; Huber, P; Li, T; López-Pavón, J; Orme, C; Pascoli, S; Meloni, D; Tang, J; Winter, W; Ohlsson, T; Zhang, H; Scotto-Lavina, L; Terranova, F; Bonesini, M; Tortora, L; Alekou, A; Aslaninejad, M; Bontoiu, C; Kurup, A; Jenner, L J; Long, K; Pasternak, J; Pozimski, J; Back, J J; Harrison, P; Beard, K; Bogacz, A; Berg, J S; Stratakis, D; Witte, H; Snopok, P; Bliss, N; Cordwell, M; Moss, A; Pattalwar, S; Apollonio, M

    2013-01-01

    The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fr\\'ejus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of {\\mu}+ and {\\mu}- beams in a storage ring. The far detector in this case is a 100 kt Magnetised Iron Neutrino Detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular 6He and 18Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fr\\'ejus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the ph...

  4. High intensity neutrino oscillation facilities in Europe

    CERN Document Server

    Edgecock, T.R.; Davenne, T.; Densham, C.; Fitton, M.; Kelliher, D.; Loveridge, P.; Machida, S.; Prior, C.; Rogers, C.; Rooney, M.; Thomason, J.; Wilcox, D.; Wildner, E.; Efthymiopoulos, I.; Garoby, R.; Gilardoni, S.; Hansen, C.; Benedetto, E.; Jensen, E.; Kosmicki, A.; Martini, M.; Osborne, J.; Prior, G.; Stora, T.; Melo-Mendonca, T.; Vlachoudis, V.; Waaijer, C.; Cupial, P.; Chancé, A.; Longhin, A.; Payet, J.; Zito, M.; Baussan, E.; Bobeth, C.; Bouquerel, E.; Dracos, M.; Gaudiot, G.; Lepers, B.; Osswald, F.; Poussot, P.; Vassilopoulos, N.; Wurtz, J.; Zeter, V.; Bielski, J.; Kozien, M.; Lacny, L.; Skoczen, B.; Szybinski, B.; Ustrzycka, A.; Wroblewski, A.; Marie-Jeanne, M.; Balint, P.; Fourel, C.; Giraud, J.; Jacob, J.; Lamy, T.; Latrasse, L.; Sortais, P.; Thuillier, T.; Mitrofanov, S.; Loiselet, M.; Keutgen, Th.; Delbar, Th.; Debray, F.; Trophine, C.; Veys, S.; Daversin, C.; Zorin, V.; Izotov, I.; Skalyga, V.; Burt, G.; Dexter, A.C.; Kravchuk, V.L.; Marchi, T.; Cinausero, M.; Gramegna, F.; De Angelis, G.; Prete, G.; Collazuol, G.; Laveder, M.; Mazzocco, M.; Mezzetto, M.; Signorini, C.; Vardaci, E.; Di Nitto, A.; Brondi, A.; La Rana, G.; Migliozzi, P.; Moro, R.; Palladino, V.; Gelli, N.; Berkovits, D.; Hass, M.; Hirsh, T.Y.; Schaumann, M.; Stahl, A.; Wehner, J.; Bross, A.; Kopp, J.; Neuffer, D.; Wands, R.; Bayes, R.; Laing, A.; Soler, P.; Agarwalla, S.K.; Cervera Villanueva, A.; Donini, A.; Ghosh, T.; Gómez Cadenas, J.J.; Hernández, P.; Martín-Albo, J.; Mena, O.; Burguet-Castell, J.; Agostino, L.; Buizza-Avanzini, M.; Marafini, M.; Patzak, T.; Tonazzo, A.; Duchesneau, D.; Mosca, L.; Bogomilov, M.; Karadzhov, Y.; Matev, R.; Tsenov, R.; Akhmedov, E.; Blennow, M.; Lindner, M.; Schwetz, T.; Fernández Martinez, E.; Maltoni, M.; Menéndez, J.; Giunti, C.; González García, M. C.; Salvado, J.; Coloma, P.; Huber, P.; Li, T.; López-Pavón, J.; Orme, C.; Pascoli, S.; Meloni, D.; Tang, J.; Winter, W.; Ohlsson, T.; Zhang, H.; Scotto-Lavina, L.; Terranova, F.; Bonesini, M.; Tortora, L.; Alekou, A.; Aslaninejad, M.; Bontoiu, C.; Kurup, A.; Jenner, L.J.; Long, K.; Pasternak, J.; Pozimski, J.; Back, J.J.; Harrison, P.; Beard, K.; Bogacz, A.; Berg, J.S.; Stratakis, D.; Witte, H.; Snopok, P.; Bliss, N.; Cordwell, M.; Moss, A.; Pattalwar, S.; Apollonio, M.

    2013-02-20

    The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fr\\'ejus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of {\\mu}+ and {\\mu}- beams in a storage ring. The far detector in this case is a 100 kt Magnetised Iron Neutrino Detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular 6He and 18Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fr\\'ejus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the ph...

  5. High intensity neutrino oscillation facilities in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Edgecock, T. R.; Caretta, O.; Davenne, T.; Densam, C.; Fitton, M.; Kelliher, D.; Loveridge, P.; Machida, S.; Prior, C.; Rogers, C.; Rooney, M.; Thomason, J.; Wilcox, D.; Wildner, E.; Efthymiopoulos, I.; Garoby, R.; Gilardoni, S.; Hansen, C.; Benedetto, E.; Jensen, E.; Kosmicki, A.; Martini, M.; Osborne, J.; Prior, G.; Stora, T.; Melo Mendonca, T.; Vlachoudis, V.; Waaijer, C.; Cupial, P.; Chancé, A.; Longhin, A.; Payet, J.; Zito, M.; Baussan, E.; Bobeth, C.; Bouquerel, E.; Dracos, M.; Gaudiot, G.; Lepers, B.; Osswald, F.; Poussot, P.; Vassilopoulos, N.; Wurtz, J.; Zeter, V.; Bielski, J.; Kozien, M.; Lacny, L.; Skoczen, B.; Szybinski, B.; Ustrycka, A.; Wroblewski, A.; Marie-Jeanne, M.; Balint, P.; Fourel, C.; Giraud, J.; Jacob, J.; Lamy, T.; Latrasse, L.; Sortais, P.; Thuillier, T.; Mitrofanov, S.; Loiselet, M.; Keutgen, Th.; Delbar, Th.; Debray, F.; Trophine, C.; Veys, S.; Daversin, C.; Zorin, V.; Izotov, I.; Skalyga, V.; Burt, G.; Dexter, A. C.; Kravchuk, V. L.; Marchi, T.; Cinausero, M.; Gramegna, F.; De Angelis, G.; Prete, G.; Collazuol, G.; Laveder, M.; Mazzocco, M.; Mezzetto, M.; Signorini, C.; Vardaci, E.; Di Nitto, A.; Brondi, A.; La Rana, G.; Migliozzi, P.; Moro, R.; Palladino, V.; Gelli, N.; Berkovits, D.; Hass, M.; Hirsh, T. Y.; Schaumann, M.; Stahl, A.; Wehner, J.; Bross, A.; Kopp, J.; Neuffer, D.; Wands, R.; Bayes, R.; Laing, A.; Soler, P.; Agarwalla, S. K.; Cervera Villanueva, A.; Donini, A.; Ghosh, T.; Gómez Cadenas, J. J.; Hernández, P.; Martín-Albo, J.; Mena, O.; Burguet-Castell, J.; Agostino, L.; Buizza-Avanzini, M.; Marafini, M.; Patzak, T.; Tonazzo, A.; Duchesneau, D.; Mosca, L.; Bogomilov, M.; Karadzhov, Y.; Matev, R.; Tsenov, R.; Akhmedov, E.; Blennow, M.; Lindner, M.; Schwetz, T.; Fernández Martinez, E.; Maltoni, M.; Menéndez, J.; Giunti, C.; González García, M. C.; Salvado, J.; Coloma, P.; Huber, P.; Li, T.; López Pavón, J.; Orme, C.; Pascoli, S.; Meloni, D.; Tang, J.; Winter, W.; Ohlsson, T.; Zhang, H.; Scotto-Lavina, L.; Terranova, F.; Bonesini, M.; Tortora, L.; Alekou, A.; Aslaninejad, M.; Bontoiu, C.; Kurup, A.; Jenner, L. J.; Long, K.; Pasternak, J.; Pozimski, J.; Back, J. J.; Harrison, P.; Beard, K.; Bogacz, A.; Berg, J. S.; Stratakis, D.; Witte, H.; Snopok, P.; Bliss, N.; Cordwell, M.; Moss, A.; Pattalwar, S.; Apollonio, M.

    2013-02-01

    The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fr\\'ejus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of {\\mu}+ and {\\mu}- beams in a storage ring. The far detector in this case is a 100 kt Magnetised Iron Neutrino Detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular 6He and 18Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fr\\'ejus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. However, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive.

  6. High intensity specular reflectometry - first experiments

    CERN Document Server

    Stahn, J; Panzner, T

    2011-01-01

    Selene is the attempt to implement a new scheme for high-intensity specular reflectometry. Instead of a highly collimated beam one uses a convergent beam covering a large angular range. The angular resolution is then performed by a position-sensitive detector. Off-specular scattering in this set-up leads to some background, but for screening of wide parameter ranges (e.g. temperature, electric and magnetic fields) the intensity gain of at least one order of magnitude is essential. If necessary, the high precession measurements (even with off-specular components) then are performed with the conventional set-up. The heart of this new set-up is an elliptically focusing guide element of 2\\,m length. Though this guide is optimised for the use on the TOF reflectometer Amor at SINQ, it can be used as stand-alone device to check the possible application also for other neutron scattering techniques. The first measurements on AMOR confirmed the general concept and the various operation modes. A draw-back occurred due t...

  7. High-intensity sweeteners and energy balance.

    Science.gov (United States)

    Swithers, Susan E; Martin, Ashley A; Davidson, Terry L

    2010-04-26

    Recent epidemiological evidence points to a link between a variety of negative health outcomes (e.g. metabolic syndrome, diabetes and cardiovascular disease) and the consumption of both calorically sweetened beverages and beverages sweetened with high-intensity, non-caloric sweeteners. Research on the possibility that non-nutritive sweeteners promote food intake, body weight gain, and metabolic disorders has been hindered by the lack of a physiologically-relevant model that describes the mechanistic basis for these outcomes. We have suggested that based on Pavlovian conditioning principles, consumption of non-nutritive sweeteners could result in sweet tastes no longer serving as consistent predictors of nutritive postingestive consequences. This dissociation between the sweet taste cues and the caloric consequences could lead to a decrease in the ability of sweet tastes to evoke physiological responses that serve to regulate energy balance. Using a rodent model, we have found that intake of foods or fluids containing non-nutritive sweeteners was accompanied by increased food intake, body weight gain, accumulation of body fat, and weaker caloric compensation, compared to consumption of foods and fluids containing glucose. Our research also provided evidence consistent with the hypothesis that these effects of consuming saccharin may be associated with a decrement in the ability of sweet taste to evoke thermic responses, and perhaps other physiological, cephalic phase, reflexes that are thought to help maintain energy balance.

  8. High intensity neutrino oscillation facilities in Europe

    Directory of Open Access Journals (Sweden)

    T. R. Edgecock

    2013-02-01

    Full Text Available The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fréjus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of μ^{+} and μ^{-} beams in a storage ring. The far detector in this case is a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular ^{6}He and ^{18}Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fréjus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. However, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive.

  9. EFFECT OF INTERMITTENT SUB-MAXIMAL EXERCISE ON PERCENT BODY FAT USING LEG-TO-LEG BIOELECTRICAL IMPEDANCE ANALYSIS IN CHILDREN

    Directory of Open Access Journals (Sweden)

    Joseph L. Andreacci

    2006-09-01

    Full Text Available The purpose of this investigation was to determine the effect of intermittent sub-maximal exercise on percent body fat (%BF estimated by leg-to-leg bioelectrical impedance analysis (LBIA in children. Fifty-nine children (29 girls; 30 boys mean age 9.0 ± 1.3 years participated in this study. LBIA measured %BF values were obtained immediately before and within five minutes after completing an intermittent exercise protocol consisting of three 8-minute sub-maximal exercise bouts (2.74 km·hr-1, 0% grade; 4.03 km·hr-1, 0% grade; and 5.47 km·hr-1, 0% grade each separated by a 5-min seated rest period. The three exercise bouts corresponded to 56%, 61% and 71% of maximal heart rate. Significant differences (p < 0.001 were observed for fat mass, fat free mass, total body water, and body weight, post-exercise in both groups. Significant reductions (p < 0.001 in %BF were observed post-exercise in the female (23.1 ± 9.9 vs. 21.8 ± 9. 9 % and male (23.3 ± 10.5 vs. 21.8 ± 10.2 % children when compared to pre-exercise values. However, for the majority of the subjects (females = 86%; males = 73% the decrease in %BF post- exercise was less than 2.0 %BF. These data indicate that sub-maximal intermittent exercise, that may be representative of daily free-form activities in children, will most likely have a limited impact on %BF estimates when the assessment is performed immediately post-exercise

  10. Effect of intermittent sub-maximal exercise on percent body fat using leg-to-leg bioelectrical impedance analysis in children.

    Science.gov (United States)

    L Andreacci, Joseph; B Dixon, Curt; Ledezma, Christina; L Goss, Fredric

    2006-01-01

    The purpose of this investigation was to determine the effect of intermittent sub-maximal exercise on percent body fat (%BF) estimated by leg-to-leg bioelectrical impedance analysis (LBIA) in children. Fifty-nine children (29 girls; 30 boys) mean age 9.0 ± 1.3 years participated in this study. LBIA measured %BF values were obtained immediately before and within five minutes after completing an intermittent exercise protocol consisting of three 8-minute sub-maximal exercise bouts (2.74 km·hr(-1), 0% grade; 4.03 km·hr(-1), 0% grade; and 5.47 km·hr(-1), 0% grade) each separated by a 5-min seated rest period. The three exercise bouts corresponded to 56%, 61% and 71% of maximal heart rate. Significant differences (p < 0.001) were observed for fat mass, fat free mass, total body water, and body weight, post-exercise in both groups. Significant reductions (p < 0.001) in %BF were observed post-exercise in the female (23.1 ± 9.9 vs. 21.8 ± 9. 9 %) and male (23.3 ± 10.5 vs. 21.8 ± 10.2 %) children when compared to pre-exercise values. However, for the majority of the subjects (females = 86%; males = 73%) the decrease in %BF post- exercise was less than 2.0 %BF. These data indicate that sub-maximal intermittent exercise, that may be representative of daily free-form activities in children, will most likely have a limited impact on %BF estimates when the assessment is performed immediately post-exercise. Key PointsLBIA measures of body weight, percent body fat, fat mass, fat free mass and total body water were significantly lower after the intermittent sub-maximal exercise.The reductions in percent body fat for girls (1.4%) and boys (1.5%) compare favorably to previous investigations.Intermittent exercise, that may be representative of daily free-form activities in children, will most likely have a limited impact on LBIA percent body fat estimates.

  11. Effects of exercise-induced muscle damage on resting metabolic rate, sub-maximal running and post-exercise oxygen consumption.

    Science.gov (United States)

    Burt, Dean Gareth; Lamb, Kevin; Nicholas, Ceri; Twist, Craig

    2014-01-01

    Exercise-induced muscle damage (EIMD), described as the acute weakness of the musculature after unaccustomed eccentric exercise, increases oxidative metabolism at rest and during endurance exercise. However, it is not known whether oxygen uptake during recovery from endurance exercise is increased when experiencing symptoms of EIMD. Therefore, the purpose of this study was to investigate the effects of EIMD on physiological and metabolic responses before, during and after sub-maximal running. After a 12 h fast, eight healthy male participants completed baseline measurements comprising resting metabolic rate (RMR), indirect markers of EIMD, 10 min of sub-maximal running and 30 min of recovery to ascertain excess post-exercise oxygen consumption (EPOC). Measurements were then repeated at 24 and 48 h after 100 Smith-machine squats. Data analysis revealed significant (PEPOC were increased in the two days after squatting exercise (PEPOC. Individuals engaging in unaccustomed resistance exercise that results in muscle damage should be mindful of the increases in resting energy expenditure and increased metabolic demand to exercise in the days that follow.

  12. The effect of high pass filtering and non-linear normalization on the EMG-force relationship during sub-maximal finger exertions.

    Science.gov (United States)

    McDonald, Alison C; Sanei, Kia; Keir, Peter J

    2013-06-01

    Muscle force estimates are important for full understanding of the musculoskeletal system and EMG is a modeling method used to estimate muscle force. The purpose of this investigation was to examine the effect of high pass filtering and non-linear normalization on the EMG-force relationship of sub-maximal finger exertions. Sub-maximal isometric ramp exertions were performed under three conditions (i) extension with restraint at the mid-proximal phalanx, (ii) flexion at the proximal phalanx and (iii) flexion at the distal phalanx. Thirty high pass filter designs were compared to a standardized processing procedure and an exponential fit equation was used for non-linear normalization. High pass filtering significantly reduced the %RMS error and increased the peak cross correlation between EMG and force in the distal flexion condition and in the other two conditions there was a trend towards improving force predictions with high pass filtering. The degree of linearity differed between the three contraction conditions and high pass filtering improved the linearity in all conditions. Non-linear normalization had greater impact on the EMG-force relationship than high pass filtering. The difference in optimal processing parameters suggests that high pass filtering and linearity are dependent on contraction mode as well as the muscle analyzed.

  13. The effect of Sub-maximal exercise-rehabilitation program on cardio-respiratory endurance indexes and oxygen pulse in patients with spastic cerebral palsy

    Directory of Open Access Journals (Sweden)

    M Izadi

    2006-05-01

    Full Text Available Background: Physical or cardio-respiratory fitness are of the best important physiological variables in children with cerebral palsy (CP, but the researches on exercise response of individuals with CP are limited. Our aim was to determine the effect of sub-maximal rehabilitation program (aerobic exercise on maximal oxygen uptake, oxygen pulse and cardio- respiratory physiological variables of children with moderate to severe spastic cerebral palsy diplegia and compare with able-bodied children. Methods: In a controlled clinical trial study, 15 children with diplegia spastic cerebral palsy, were recruited on a voluntarily basis (experimental group and 18 subjects without neurological impairments selected as control group. In CP group, aerobic exercise program performed on the average of exercise intensity (144 beat per minute of heart rate, 3 times a week for 3 months. The time of each exercise session was 20-25 minutes. Dependent variables were measured in before (pretest and after (post test of rehabilitation program through Mac Master Protocol on Tantories cycle ergometer in CP group and compared with the control group. Results: The oxygen pulse (VO2/HR during ergometery protocol was significantly lower in CP group than normal group (P<0.05. No significant statistical difference in maximal oxygen uptake (VO2 max was found between groups. The rehabilitation program leads to little increase of this variable in CP group. After sub-maximal exercise in pretest and post test, the heart rate of patient group was greater than control group, and aerobic exercise leads to significant decrease in heart rate in CP patients(P<0.05. Conclusion: The patients with spastic cerebral palsy, because of high muscle tone, severe spasticity and involuntarily movements have higher energy cost and lower aerobic fitness than normal people. The rehabilitation exercise program can improve physiological function of muscle and cardio-respiratory endurance in these

  14. Análise da resposta da freqüência cardíaca durante a realização de exercício isocinético excêntrico de grupamento extensor de joelho Analysis of heart rate response during eccentric isokinetic exercise of knee extensor muscle group

    Directory of Open Access Journals (Sweden)

    CA Malfatti

    2006-01-01

    Full Text Available Objetivo: Investigar a magnitude da resposta da freqüência cardíaca durante o exercício isocinético excêntrico do grupamento extensor do joelho, em diferentes velocidades angulares. Materiais e Métodos: Dez voluntários jovens, sadios e ativos foram submetidos a contração excêntrica máxima do grupo extensor do joelho dominante. Foi utilizado um dinamômetro isocinético, nas velocidades de 30º/s, 60º/s e 120º/s, ordenadas aleatoriamente. A FC foi obtida batimento a batimento, na derivação eletrocardiográfica MC5 modificada, durante 60s pré-exercício, durante o tempo de contração, sendo cinco repetições para cada velocidade, e por 120s após o esforço. Foram calculadas: FC média dos 60s pré-exercício, FC pico atingida ao final do esforço, e variação da FC (DFC, além dos valores do pico de torque. Também foram comparados valores da FC média dos 6 minutos pré-exercício com os 6 minutos de recuperação. Os resultados foram comparados pelo teste de Friedman com post hoc de Dunn. O nível de significância estabelecido foi de 5%. Resultados: Não foram observadas diferenças estatisticamente significantes entre os valores medianos da FC de repouso (68bpm para 30º/s e 60º/s, 70bpm para 120º/s, FC pico (107bpm para 30º/s, 103 em 60º/s e 100bpm em 120º/s e DFC (37bpm para 30º/s, 35bpmem 60º/s e 27bpm para 120ºs, além do pico de torque (209,5N/m para 30º/s, 217,2N/m em 60º/s e 210,6N/m para 120º/s. A mediana dos valores de FC anteriores ao esforço foi semelhante aos de recuperação (67bpm. Conclusão:A magnitude de resposta da FC foi semelhante, durante atividade muscular excêntrica, indicando uma mesma sobrecarga cardíaca, independente da velocidade angular realizada.Objective: To investigate heart rate response magnitudes during eccentric isokinetic exercise of the knee extensor muscles, at different angular velocities. Method: Ten healthy and active young volunteers underwent maximum eccentric

  15. High Intensity Accelerator and Neutron Source in China

    Science.gov (United States)

    Guan, Xialing; Wei, J.; Loong, Chun

    2011-06-01

    High intensity Accelerator is being studied all over world for numerous applications, which includes the waste transmutation, spallation neutron source and material irradiation facilities. The R/D activities of the technology of High intensity accelerator are also developed in China for some year, and have some good facilities around China. This paper will reports the status of some high intensity accelerators and neutron source in China, which including ADS/RFQ; CARR; CSNS; PKUNIFTY & CPHS. This paper will emphatically report the Compact Pulsed Hadron Source (CPHS) led by the Department of Engineering Physics of Tsinghua University in Beijing, China.

  16. ELECTRON CLOUD EFFECTS IN HIGH INTENSITY PROTON ACCELERATORS.

    Energy Technology Data Exchange (ETDEWEB)

    WEI,J.; MACEK,R.J.

    2002-04-14

    One of the primary concerns in the design and operation of high-intensity proton synchrotrons and accumulators is the electron cloud and associated beam loss and instabilities. Electron-cloud effects are observed at high-intensity proton machines like the Los Alamos National Laboratory's PSR and CERN's SPS, and investigated experimentally and theoretically. In the design of next-generation high-intensity proton accelerators like the Spallation Neutron Source ring, emphasis is made in minimizing electron production and in enhancing Landau damping. This paper reviews the present understanding of the electron-cloud effects and presents mitigation measures.

  17. High Intensity Tactical Power Sources for the 1990 Army.

    Science.gov (United States)

    conceptual or physical study which may become feasible as high intensity power sources . These considerations include present state of the art of...requirements, energy and power output capabilities, and fixed costs. From these tables, it may be seen that a variety of electrical power sources would be...required to satisfy diverse requirements, but an attempt is made to categorize possible high intensity power sources into their areas of optimum

  18. Concept for a new high resolution high intensity diffractometer

    Energy Technology Data Exchange (ETDEWEB)

    Stuhr, U. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    A concept of a new time-of-flight powder-diffractometer for a thermal neutral beam tube at SINQ is presented. The design of the instrument optimises the contradictory conditions of high intensity and high resolution. The high intensity is achieved by using many neutron pulses simultaneously. By analysing the time-angle-pattern of the detected neutrons an assignment of the neutrons to a single pulse is possible. (author) 3 figs., tab., refs.

  19. Effect of high intensity ultrasound on the allergenicity of shrimp

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The tropomyosin fraction of shrimp proteins is potentially responsible for allergic reaction in individuals with genetic predisposition to allergy. However, there are no efficient and safe methods to reduce its allergenicity. High intensity ultrasound is known to change the structure of proteins. This study is aimed at assessing high intensity ultrasound's effect on the allergenicity of shrimp allergen. Shrimp and purified shrimp allergen were treated with high intensity ultrasound for 30~180 min. Extracts of treated samples were analyzed by enzyme-linked immunosorbent assay (ELISA) with pool serum of shrimp allergy patients and polyclonal anti-allergen antibodies and by immunoblotting after polyacrylamide gel electrophoresis. Shrimp treated with high intensity ultrasound showed a decrease in allergenicity measured with ELISA. A linear relationship between the immune response induced by treated shrimp allergen and the applied treatment time was observed. The decrease in allergenicity was confirmed by immunoblot assays with shrimp allergic patients serum. Allergenicity of shrimp allergen extracted from treated shrimp was higher than that of purified shrimp allergen with the same treatment time. Gel-filtration HPLC was applied for analysis of shrimp allergen after treatment with high intensity ultrasound. Some fractions were appeared with increasing treatment time. The results suggested that high intensity ultrasound could be used to reduce the allergenicity of shrimp.

  20. Repeated high-intensity exercise in professional rugby union.

    Science.gov (United States)

    Austin, Damien; Gabbett, Tim; Jenkins, David

    2011-07-01

    The aim of the present study was to describe the frequency, duration, and nature of repeated high-intensity exercise in Super 14 rugby union. Time-motion analysis was used during seven competition matches over the 2008 and 2009 Super 14 seasons; five players from each of four positional groups (front row forwards, back row forwards, inside backs, and outside backs) were assessed (20 players in total). A repeated high-intensity exercise bout was considered to involve three or more sprints, and/or tackles and/or scrum/ruck/maul activities within 21 s during the same passage of play. The range of repeated high-intensity exercise bouts for each group in a match was as follows: 11-18 for front row forwards, 11-21 for back row forwards, 13-18 for inside backs, and 2-11 for outside backs. The durations of the most intense repeated high-intensity exercise bouts for each position ranged from 53 s to 165 s and the minimum recovery periods between repeated high-intensity exercise bouts ranged from 25 s for the back row forwards to 64 s for the front row forwards. The present results show that repeated high-intensity exercise bouts vary in duration and activities relative to position but all players in a game will average at least 10 changes in activity in the most demanding bouts and complete at least one tackle and two sprints. The most intense periods of activity are likely to last as long as 120 s and as little as 25 s recovery may separate consecutive repeated high-intensity exercise bouts. The present findings can be used by coaches to prepare their players for the most demanding passages of play likely to be experienced in elite rugby union.

  1. Sub-maximal and maximal Yo-Yo intermittent endurance test level 2: heart rate response, reproducibility and application to elite soccer

    DEFF Research Database (Denmark)

    Bradley, Paul S; Mohr, Magni; Bendiksen, Mads

    2011-01-01

    The aims of this study were to (1) determine the reproducibility of sub-maximal and maximal versions of the Yo-Yo intermittent endurance test level 2 (Yo-Yo IE2 test), (2) assess the relationship between the Yo-Yo IE2 test and match performance and (3) quantify the sensitivity of the Yo-Yo IE2 test...... to detect test-retest changes and discriminate between performance for different playing standards and positions in elite soccer. Elite (n = 148) and sub-elite male (n = 14) soccer players carried out the Yo-Yo IE2 test on several occasions over consecutive seasons. Test-retest coefficient of variation (CV......) in Yo-Yo IE2 test performance and heart rate after 6 min were 3.9% (n = 37) and 1.4% (n = 32), respectively. Elite male senior and youth U19 players Yo-Yo IE2 performances were better (P ...

  2. COMPARATIVE STUDY OF SUB - MAXIMAL EXERCISE TEST IN A GROUP OF 20 COLLEGE STUDENTS IN THE AGE GROUP OF 18 - 21 YEARS

    Directory of Open Access Journals (Sweden)

    Karuna Devi

    2013-10-01

    Full Text Available ABSTRACT : This study aims to compa re two widely applied tests such as step - test and bicycle ergometer. It was seen that body - weight has significant influence on the validity of sub - maximal exercise test [1]. In the development of exercise prescription knowing the actual energy expenditure with prescribed activity is essential particularly in weight loss programmes [2]. Recovery heart - rate from standardized stepping exercise, can classify people on cardiovascular fitness and VO 2 max with reasonable acceptable accuracy. Post - exercise heart - ra te is the primary parameter for estimating aerobic capacity [3], these evaluations are based on the regression among resting heart - rate, load intensity and maximum O 2 uptake. In the present study, the influence of body weight VO 2 max, BMI and speed were ta ken into consideration. The results showed the reliability & sensitivity of two tests are remarkably different. Evaluation of maximal O 2 consumption was determined by Astrand’s evaluation test on Bicycle Ergometer [4] and the step - test evaluated by Von Dob len formula, results seen were significantly different. The participants had a higher O 2 consumption rate in the step - test. The assessment of cardiovascular fitness commonly assessed by the measurements of maximum O 2 uptake can be a useful tool in promotin g health. It enables the baseline of the fitness to be established, it enables an exercise programme to be more individually prescribed, the assessment of aerobic capacity is becoming more common in medical screening.

  3. High-Intensity Interval Training for Improving Postprandial Hyperglycemia

    Science.gov (United States)

    Little, Jonathan P.; Francois, Monique E.

    2014-01-01

    High-intensity interval training (HIIT) has garnered attention in recent years as a time-efficient exercise option for improving cardiovascular and metabolic health. New research demonstrates that HIIT may be particularly effective for improving postprandial hyperglycemia in individuals with, or at risk for, type 2 diabetes (T2D). These findings…

  4. Nonlinear Behavior in High-Intensity Discharge Lamps

    CERN Document Server

    Baumann, Bernd; Wolff, Marcus; Manders, Freddy; Suijker, Jos

    2015-01-01

    The light flicker problem of high intensity discharge lamps is studied numerically and experimentally. It is shown that in some respects the systems behaves very similar to the forced Duffing oscillator with a softening spring. In particular, the jump phenomenon and hysteresis are observed in the simulations and in the experiments.

  5. Nonlinear behavior in high-intensity discharge lamps

    Science.gov (United States)

    Baumann, Bernd; Schwieger, Joerg; Wolff, Marcus; Manders, Freddy; Suijker, Jos

    2016-06-01

    The light flicker problem of high intensity discharge lamps is studied numerically and experimentally. It is shown that in some respects the systems behave very similar to the forced Duffing oscillator with a softening spring. In particular, the jump phenomenon and hysteresis are observed in the simulations and in the experiments.

  6. Acute plasma volume change with high-intensity sprint exercise.

    Science.gov (United States)

    Bloomer, Richard J; Farney, Tyler M

    2013-10-01

    When exercise is of long duration or of moderate to high intensity, a decrease in plasma volume can be observed. This has been noted for both aerobic and resistance exercise, but few data are available with regard to high-intensity sprint exercise. We measured plasma volume before and after 3 different bouts of acute exercise, of varying intensity, and/or duration. On different days, men (n = 12; 21-35 years) performed aerobic cycle exercise (60 minutes at 70% heart rate reserve) and 2 different bouts of cycle sprints (five 60-second sprints at 100% maximum wattage obtained during graded exercise testing (GXT) and ten 15-second sprints at 200% maximum wattage obtained during GXT). Blood was collected before and 0, 30, and 60 minutes postexercise and analyzed for hematocrit and hemoglobin and plasma volume was calculated. Plasma volume decreased significantly for all exercise bouts (p sprint bouts (∼19%) compared with aerobic exercise bouts (∼11%). By 30 minutes postexercise, plasma volume approached pre-exercise values. We conclude that acute bouts of exercise, in particular high-intensity sprint exercise, significantly decrease plasma volume during the immediate postexercise period. It is unknown what, if any negative implications these transient changes may have on exercise performance. Strength and conditioning professionals may aim to rehydrate athletes appropriately after high-intensity exercise bouts.

  7. Parallel Beam Dynamics Code Development for High Intensity Cyclotron

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>1 Parallel PIC algorithm Self field solver is the key part of a high intensity beam dynamic PIC code which usually adopts the P-M (Particle-Mesh) method to solve the space charge. The P-M method is composed of four major

  8. Annotated bibliography on high-intensity linear accelerators. [240 citations

    Energy Technology Data Exchange (ETDEWEB)

    Jameson, R.A.; Roybal, E.U.

    1978-01-01

    A technical bibliography covering subjects important to the design of high-intensity beam transport systems and linear accelerators is presented. Space charge and emittance growth are stressed. Subject and author concordances provide cross-reference to detailed citations, which include an abstract and notes on the material. The bibliography resides in a computer database that can be searched for key words and phrases.

  9. Simulation study of the high intensity S-Band photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiongwei; Nakajima, Kazuhisa [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

    2001-10-01

    In this paper, we report the results of simulation study of the high intensity S-Band photoinjector. The aim of the simulation study is to transport high bunch charge with low emittance evolution. The simulation result shows that 7nC bunch with rms emittance 22.3 {pi} mm mrad can be outputted at the exit of photoinjector. (author)

  10. Reuse Recycler: High Intensity Proton Stacking at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, P. [Fermilab

    2016-07-17

    After a successful career as an antiproton storage and cooling ring, Recycler has been converted to a high intensity proton stacker for the Main Injector. We discuss the commissioning and operation of the Recycler in this new role, and the progress towards the 700 kW design goal.

  11. Efeito de um programa de resistência muscular na capacidade funcional e na força muscular dos extensores do joelho em idosas pré-frágeis da comunidade: ensaio clínico aleatorizado do tipo crossover Impact of resistance exercise program on functional capacity and muscular strength of knee extensor in pre-frail community-dwelling older women: a randomized crossover trial

    Directory of Open Access Journals (Sweden)

    Lygia P. Lustosa

    2011-08-01

    vulnerability. OBJECTIVE: The aim of this study was to verify the effect of a muscle-strengthening program with load in pre-frail elder women with regards to the functional capacity, knee extensor muscle strength and their correlation. METHODS: Thrity-two pre-frail community-dwelling women participated in this study. Potential participants with cognitive impairment (MEEM, lower extremities orthopedic surgery, fractures, inability to walk unaided, neurological diseases, acute inflammatory disease, tumor growth, regular physical activity and current use of immunomodulators were excluded. All partcipants were evaluated by a blinded assessor using: Timed up and go (TUG, 10-Meter Walk Test (10MWT and knee extensor muscle strength (Byodex System 3 Pro® isokinetic dynamometer at angular speeds of 60 and 180(0/s. The intervention consisted of strengthening exercises of the lower extremities at 70% of 1RM, three times/ week for ten weeks. The statistical analysis was performed using the ANOVA and Spearman tests RESULTS: After the intervention, it was observed statistical significance on the work at 180(0/s (F=12.71, p=0.02, on the power at 180(0/s (F=15.40, p=0.02 and on the functional capacity (TUG, F=9.54, p=0.01; TC10, F=3.80, p=0.01. There was a good negative and statistically significant correlation between the TUG and work at 60(0/s, such as the TUG and work at 180(0/s (r=-0.65, p=0.01; r=-0.72, p=0.01. CONCLUSION: The intervention improved the muscular power and the functional capacity. The increase of the power correlated with function, which is an important variable of the quality of life in the pre-frail elders. Article registered in the ISRCT register under number ISRCTN62824599.

  12. High-Intensity Focused Ultrasound Therapy: an Overview for Radiologists

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Sun; Rhim, Hyun Chul; Lim, Hyo Keun; Choi, Dong Il [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Choi, Min Joo [College of Medicine, Cheju National University, Jeju (Korea, Republic of)

    2008-08-15

    High-intensity focused ultrasound therapy is a novel, emerging, therapeutic modality that uses ultrasound waves, propagated through tissue media, as carriers of energy. This completely non-invasive technology has great potential for tumor ablation as well as hemostasis, thrombolysis and targeted drug/gene delivery. However, the application of this technology still has many drawbacks. It is expected that current obstacles to implementation will be resolved in the near future. In this review, we provide an overview of high-intensity focused ultrasound therapy from the basic physics to recent clinical studies with an interventional radiologist's perspective for the purpose of improving the general understanding of this cutting-edge technology as well as speculating on future developments

  13. High-intensity focused ultrasound therapy: an overview for radiologists.

    Science.gov (United States)

    Kim, Young-sun; Rhim, Hyunchul; Choi, Min Joo; Lim, Hyo Keun; Choi, Dongil

    2008-01-01

    High-intensity focused ultrasound therapy is a novel, emerging, therapeutic modality that uses ultrasound waves, propagated through tissue media, as carriers of energy. This completely non-invasive technology has great potential for tumor ablation as well as hemostasis, thrombolysis and targeted drug/gene delivery. However, the application of this technology still has many drawbacks. It is expected that current obstacles to implementation will be resolved in the near future. In this review, we provide an overview of high-intensity focused ultrasound therapy from the basic physics to recent clinical studies with an interventional radiologist's perspective for the purpose of improving the general understanding of this cutting-edge technology as well as speculating on future developments.

  14. Review of High-intensity Interval Training in Cardiac Rehabilitation.

    Science.gov (United States)

    Ito, Shigenori; Mizoguchi, Tatsuya; Saeki, Tomoaki

    2016-01-01

    For the secondary prevention of cardiovascular disease, comprehensive cardiac rehabilitation is required. This involves optimal medical therapy, education on nutrition and exercise therapy, and smoking cessation. Of these, efficient exercise therapy is a key factor. A highly effective training protocol is therefore warranted, which requires a high rate of compliance. Although moderate-intensity continuous training has been the main training regimen recommended in cardiac rehabilitation guidelines, high-intensity interval training has been reported to be more effective in the clinical and experimental setting from the standpoint of peak oxygen uptake and central and peripheral adaptations. In this review, we illustrate the scientific evidence for high-intensity interval training. We then verify this evidence and discuss its significance and the remaining issues.

  15. Plasma-based polarization modulator for high-intensity lasers

    Science.gov (United States)

    Chen, Zi-Yu; Pukhov, Alexander

    2016-12-01

    Manipulation of laser pulses at high intensities is an important yet challenging issue. New types of plasma-based optical devices are promising alternatives to achieve this goal. Here we propose to modulate the polarization state of intense lasers based on oblique reflection from solid-plasma surfaces. A new analytical description is presented considering the plasma as an uniaxial medium that causes birefringence effect. Particle-in-cell simulation results numerically demonstrate that such a scheme can provide a tunable polarization control of the laser pulses even in the relativistic regime. The results are thus relevant for the design of compact, easy to use, and versatile polarization modulators for high-intensity laser pulses.

  16. CW high intensity non-scaling FFAG proton drivers

    CERN Document Server

    Johnstone, C; Makino, K; Snopok, P

    2012-01-01

    Accelerators are playing increasingly important roles in basic science, technology, and medicine including nuclear power, industrial irradiation, material science, and neutrino production. Proton and light-ion accelerators in particular have many research, energy and medical applications, providing one of the most effective treatments for many types of cancer. Ultra high-intensity and high-energy (GeV) proton drivers are a critical technology for accelerator-driven sub-critical reactors (ADS) and many HEP programs (Muon Collider). These high-intensity GeV-range proton drivers are particularly challenging, encountering duty cycle and space-charge limits in the synchrotron and machine size concerns in the weaker-focusing cyclotrons; a 10-20 MW proton driver is not presently considered technically achievable with conventional re-circulating accelerators. One, as-yet, unexplored re-circulating accelerator, the Fixed-field Alternating Gradient, or FFAG, is an attractive alternative to the cyclotron. Its strong foc...

  17. Spallation neutron source and other high intensity froton sources

    Energy Technology Data Exchange (ETDEWEB)

    Weiren Chou

    2003-02-06

    This lecture is an introduction to the design of a spallation neutron source and other high intensity proton sources. It discusses two different approaches: linac-based and synchrotron-based. The requirements and design concepts of each approach are presented. The advantages and disadvantages are compared. A brief review of existing machines and those under construction and proposed is also given. An R&D program is included in an appendix.

  18. Muscle fatigue during high-intensity exercise in children.

    Science.gov (United States)

    Ratel, Sébastien; Duché, Pascale; Williams, Craig A

    2006-01-01

    Children are able to resist fatigue better than adults during one or several repeated high-intensity exercise bouts. This finding has been reported by measuring mechanical force or power output profiles during sustained isometric maximal contractions or repeated bouts of high-intensity dynamic exercises. The ability of children to better maintain performance during repeated high-intensity exercise bouts could be related to their lower level of fatigue during exercise and/or faster recovery following exercise. This may be explained by muscle characteristics of children, which are quantitatively and qualitatively different to those of adults. Children have less muscle mass than adults and hence, generate lower absolute power during high-intensity exercise. Some researchers also showed that children were equipped better for oxidative than glycolytic pathways during exercise, which would lead to a lower accumulation of muscle by-products. Furthermore, some reports indicated that the lower ability of children to activate their type II muscle fibres would also explain their greater resistance to fatigue during sustained maximal contractions. The lower accumulation of muscle by-products observed in children may be suggestive of a reduced metabolic signal, which induces lower ratings of perceived exertion. Factors such as faster phosphocreatine resynthesis, greater oxidative capacity, better acid-base regulation, faster readjustment of initial cardiorespiratory parameters and higher removal of metabolic by-products in children could also explain their faster recovery following high-intensity exercise.From a clinical point of view, muscle fatigue profiles are different between healthy children and children with muscle and metabolic diseases. Studies of dystrophic muscles in children indicated contradictory findings of changes in contractile properties and the muscle fatigability. Some have found that the muscle of boys with Duchenne muscular dystrophy (DMD) fatigued less

  19. The effect of progressive high-intensity inspiratory muscle training and fixed high-intensity inspiratory muscle training on the asymmetry of diaphragm thickness in stroke patients

    OpenAIRE

    Jung, Ju-hyeon; Kim, Nan-soo

    2015-01-01

    [Purpose] This study investigated the effects of progressive load and fixed load high-intensity inspiratory muscle training on the asymmetry of diaphragm thickness in stroke patients. [Subjects] Twenty-one stroke patients were assigned to one of three groups: progressive load high-intensity inspiratory muscle training (n = 8), fixed load high-intensity inspiratory muscle training (n = 6), and controls (n = 7). [Methods] The progressive load and fixed load high-intensity inspiratory muscle tra...

  20. Electron cloud instability in high intensity proton rings

    Directory of Open Access Journals (Sweden)

    K. Ohmi

    2002-11-01

    Full Text Available An e^{-}p instability has been observed in some proton rings. The instability, which causes beam loss, limits the performance of the ring. The instability may be serious for 3 and 50 GeV proton storage rings in the Japan Proton Accelerator Research Complex (J-PARC. We study the e^{-}p instability in several high intensity proton storage rings operated in the world. This work informs J-PARC of the necessity to cure the instability, for example, by applying a TiN coating on the chamber surface.

  1. Intelligent Controller of Digital High Intensity Discharge Lamp

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    High-intensity discharge (HID) lamps include these types of electrical lamps: mercury vapor, metal halide (also HQI), high-pressure sodium, low-pressure sodium and less commonly, xenon short-arc lamps. The light-producing element of these lamp types is a well-stabilized arc discharge contained within a refractory envelope (arc tube) with wall loading in excess of 3 W/cm (19.4 W/in.). Compared to fluorescent and incandescent lamps, HID lamps produce a much larger quantity of light in a relatively small package. With tests made by the National Quality Supervision and

  2. The joint project for high-intensity proton accelerators

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-08-01

    Japan Atomic Energy Research Institute (JAERI) and the High Energy Accelerator Research Organization (KEK) agreed to promote the joint project integrating both the Neutron Science Project (NSP) of JAERI and the Japan Hadron Facility Project (JHF) of KEK for comprehensive studies on basic science and technology using high-intensity proton accelerator. This document describes the joint proposal prepared by the Joint Project Team of JAERI and KEK to construct accelerators and research facilities necessary both for the NSP and the JHF at the site of JAERI Tokai Establishment. (author)

  3. The development of a high intensity dance performance fitness test.

    Science.gov (United States)

    Redding, Emma; Weller, Peter; Ehrenberg, Shantel; Irvine, Sarah; Quin, Edel; Rafferty, Sonia; Wyon, Matthew; Cox, Carol

    2009-01-01

    While there is currently a validated dance-specific exercise method of measuring aerobic fitness, no such test has been developed to measure high intensity capabilities in dance. The purpose of this study was to initiate an intermittent high intensity dance-specific fitness test. The test was designed to be able to observe changes in heart rate (HR), thereby allowing for a measurement of physical fitness at high intensities. Sixteen professional dancers (4 males and 12 females) volunteered to take part in this study. The fitness test protocol consists of movements that are representative of contemporary dance, and contains exercise and rest periods that mimic the intermittent nature of dance. The participants performed four trials. The physiological variables measured were HR (b.min(-1)) for each one minute bout of the four minute test for all trials, oxygen uptake (VO(2)) throughout the test, and end blood lactate (BLa mmol.L) for each trial. In addition, five of the participants undertook a maximal oxygen uptake treadmill test, and the scores obtained were compared with those from the dance test. Results show HR consistency across each one minute bout of the test and across each of the four trials of testing for all participants, indicating that the test is reliable. There was good reliability between bouts of each trial (typical error as % of CV = 1.5), intraclass "r" = 0.8, and good reliability between the four trials (typical error as % of CV = 2.1), intraclass "r" = 0.82. There were no significant differences between the maximal VO(2) and BLa scores established in the treadmill and dance tests, demonstrating validity. Thus, the results of this study indicate that the high intensity dance-specific test is a reliable and valid means of assessing and monitoring the cardiovascular fitness of dancers. The test allows dancers to be assessed within an environment that they are accustomed to (the studio), using a mode of exercise that is relevant (dance), and it is

  4. High-Intensity, High Charge-State Heavy Ion Sources

    CERN Document Server

    Alessi, J

    2004-01-01

    There are many accelerator applications for high intensity heavy ion sources, with recent needs including dc beams for RIA, and pulsed beams for injection into synchrotrons such as RHIC and LHC. The present status of sources producing high currents of high charge state heavy ions will be reviewed. These sources include ECR, EBIS, and Laser ion sources. The benefits and limitations for these type sources will be described, for both dc and pulsed applications. Possible future improvements in these type sources will also be discussed.

  5. Beam instrumentation for future high intense hadron accelerators at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, M.; Hu, M.; Tassotto, G.; Thurman-Keup, R.; Scarpine, V.; Shin, S.; Zagel, J.; /Fermilab

    2008-08-01

    High intensity hadron beams of up to 2 MW beam power are a key element of new proposed experimental facilities at Fermilab. Project X, which includes a SCRF 8 GeV H{sup -} linac, will be the centerpiece of future HEP activities in the neutrino sector. After a short overview of this, and other proposed projects, we present the current status of the beam instrumentation activities at Fermilab with a few examples. With upgrades and improvements they can meet the requirements of the new beam facilities, however design and development of new instruments is needed, as shown by the prototype and conceptual examples in the last section.

  6. Development of High Intensity Beam Emittance Measurement Unit

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Three sets of High Intensity Beam Emittance Measurement Units (HIBEMUs) are being developed at Peking University. They are HIBEMU-2 (slit-wire type, one direction), HIBEMU-3 (Allison scanner type, one direction) and HIBEMU-4 (slit-wire type, two directions). For HIBEMU-2 and HIBEMU-3, more recent work has been done on software redesign in order to measure beam emittance and to draw phase diagram more efficiently and precisely. Software for control and data processing of them were developed in Labveiw environment, trying to improve calculation rationality and to offer user-friendly interface. Mechanical modification was also done for HIBEMU-3, mainly concentrating on the protection of Faraday cups from being overheated by the high intensity beam and also from interference of secondary electrons. This paper will also cover the mechanical structure as well as the software development of HIBEMU-4, which is a two-direction emittance scanner newly designed and manufactured for the high energy beam transport (HEBT) of Peking University Neutron Imaging FaciliTY (PKUNIFTY). At the end of this paper, comparison and analysis of the three HIBEMUs are given to draw forth better design of the future emittance measurement facility.

  7. Use of High Intensity Focused Ultrasound for Treating Malignant Tumors

    Institute of Scientific and Technical Information of China (English)

    WenzhiChen; ZhibiaoWang; FengWu; JinBai; HuiZhu; JianzhongZou; KequanLi; FanglinXie; ZhilongWang

    2004-01-01

    OBJECTIVE To investigate the efficacy and side effects of high intensity focused ultrasound(HIFU) in the treatment of malignant solid tumors. METHODS Thirty patients who refused surgery and/or were refractory to chemotherapy were treated by HIFU alone, with the efficacy and side effects monitored as follows: observation of vital organ signs; functional assay of important organs; imaging examinations including: digital subtraction angiography (DSA), CT, MRI, single photon emission computed tomography (SPECT), large core needle biopsy, complications and metastasis. RESULTS After HIFU therapy, the vital signs remained stable and the functions of the heart, lung, kidney and liver were also normal. DSA images showed that small or larger arteries were not damaged. After a follow-up of 10-38 months(mean 23.1 months), 26 patients(87%) were alive. The volume of the tumor underwent complete regression in 10 patients. Shrinkage of the tumor volume ≥50% was observed in 13 patients. Eight of 13 patients were examined by large core needle biopsy, all showing necrosis and/or fibrosis though 3 patients(10%) had local recurrence. Two of these were retreated again by HIFU and the locally recurrent tumors were controlled. New metastases developed in 5 patients after H IFU. Two patients suffered from peripheral nerve injuriy and they have recovered during the follow-up. One patient developed skin injury. CONCLUSION High intensity focused ultrasound is effective and safe in the treatment of malignant solid tumors.

  8. A transparent vacuum window for high-intensity pulsed beams

    CERN Document Server

    Monteil, M; Veness, R

    2011-01-01

    The HiRadMat (High-Radiation to Materials) facility Ill will allow testing of accelerator components, in particular those of the Large Hadron Collider (LHC) at CERN, under the impact of high-intensity pulsed beams. To reach this intensity range, the beam will be focused on a focal point where the target to be tested is located. A 60 mm aperture vacuum window will separate the vacuum of the beam line which is kept under high vacuum 10(-8) mbar, from the test area which is at atmospheric pressure. This window has to resist collapse due to beam passage. The high-intensity of the beam means that typical materials used for standard vacuum windows (such as stainless steel, aluminium and titanium alloy) cannot endure the energy deposition induced by the beam passage. Therefore, a vacuum window has been designed to maintain the differential pressure whilst resisting collapse due to the beam impact on the window. In this paper, we will present calculations of the energy transfer from beam to window, the design of the ...

  9. High Intensity Particle Physics at PW-class laser facilities

    Science.gov (United States)

    Bulanov, Stepan; Schroeder, Carl; Esarey, Eric; Esirkepov, Timur; Kando, Masaki; Rosanov, Nikolay; Korn, Georg; Bulanov, Sergey V.; Leemans, Wim P.

    2015-11-01

    The processes typical for high intensity particle physics, i.e., the interactions of charged particles with strong electromagnetic fields, have attracted considerable interest recently. Some of these processes, previously believed to be of theoretical interest only, are now becoming experimentally accessible. High intensity electromagnetic (EM) fields significantly modify the interactions of particles and EM fields, giving rise to the phenomena that are not encountered either in classical or perturbative quantum theory of these interactions. One of such phenomena is the radiation reaction, which radically influences the electron motion in an electromagnetic standing wave formed by two super-intense counter-propagating laser pulses. Depending on the laser intensity and wavelength, either classical or quantum mode of radiation reaction prevail, or both are strong. When radiation reaction dominates, electron motion evolves to limit cycles and strange attractors. This creates a new framework for high energy physics experiments on an interaction of energetic charged particle beams and colliding super-intense laser pulses. Work supported by U.S. DOE under Contract No. DE-AC02-05CH11231.

  10. High-Intensity Sweeteners in Alternative Tobacco Products.

    Science.gov (United States)

    Miao, Shida; Beach, Evan S; Sommer, Toby J; Zimmerman, Julie B; Jordt, Sven-Eric

    2016-11-01

    Sweeteners in tobacco products may influence use initiation and reinforcement, with special appeal to adolescents. Recent analytical studies of smokeless tobacco products (snuff, snus, dissolvables) detected flavorants identical to those added to confectionary products such as hard candy and chewing gum. However, these studies did not determine the levels of sweeteners. The objective of the present study was to quantify added sweeteners in smokeless tobacco products, a dissolvable product, electronic cigarette liquids and to compare with sweetener levels in confectionary products. Sweetener content of US-sourced smokeless tobacco, electronic cigarette liquid, and confectionary product samples was analyzed by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). All smokeless products contained synthetic high intensity sweeteners, with snus and dissolvables exceeding levels in confectionary products (as much as 25-fold). All snus samples contained sucralose and most also aspartame, but no saccharin. In contrast, all moist snuff samples contained saccharin. The dissolvable sample contained sucralose and sorbitol. Ethyl maltol was the most common sweet-associated component in electronic cigarette liquids. Sweetener content was dependent on product category, with saccharin in moist snuff, an older category, sucralose added at high levels to more recently introduced products (snus, dissolvable) and ethyl maltol in electronic cigarette liquid. The very high sweetener concentrations may be necessary for the consumer to tolerate the otherwise aversive flavors of tobacco ingredients. Regulation of sweetener levels in smokeless tobacco products may be an effective measure to modify product attractiveness, initiation and use patterns. Dissolvables, snus and electronic cigarettes have been promoted as risk-mitigation products due to their relatively low content of nitrosamines and other tobacco toxicants. This study is the first to quantify high

  11. High-Intensity Sweeteners in Alternative Tobacco Products

    Science.gov (United States)

    Miao, Shida; Beach, Evan S.; Sommer, Toby J.; Zimmerman, Julie B.

    2016-01-01

    Introduction: Sweeteners in tobacco products may influence use initiation and reinforcement, with special appeal to adolescents. Recent analytical studies of smokeless tobacco products (snuff, snus, dissolvables) detected flavorants identical to those added to confectionary products such as hard candy and chewing gum. However, these studies did not determine the levels of sweeteners. The objective of the present study was to quantify added sweeteners in smokeless tobacco products, a dissolvable product, electronic cigarette liquids and to compare with sweetener levels in confectionary products. Methods: Sweetener content of US-sourced smokeless tobacco, electronic cigarette liquid, and confectionary product samples was analyzed by liquid chromatography-electrospray ionization–mass spectrometry (LC-ESI-MS). Results: All smokeless products contained synthetic high intensity sweeteners, with snus and dissolvables exceeding levels in confectionary products (as much as 25-fold). All snus samples contained sucralose and most also aspartame, but no saccharin. In contrast, all moist snuff samples contained saccharin. The dissolvable sample contained sucralose and sorbitol. Ethyl maltol was the most common sweet-associated component in electronic cigarette liquids. Discussion: Sweetener content was dependent on product category, with saccharin in moist snuff, an older category, sucralose added at high levels to more recently introduced products (snus, dissolvable) and ethyl maltol in electronic cigarette liquid. The very high sweetener concentrations may be necessary for the consumer to tolerate the otherwise aversive flavors of tobacco ingredients. Regulation of sweetener levels in smokeless tobacco products may be an effective measure to modify product attractiveness, initiation and use patterns. Implications: Dissolvables, snus and electronic cigarettes have been promoted as risk-mitigation products due to their relatively low content of nitrosamines and other tobacco

  12. Pedalling rate affects endurance performance during high-intensity cycling

    DEFF Research Database (Denmark)

    Nielsen, Jens Steen; Hansen, Ernst Albin; Sjøgaard, Gisela

    2004-01-01

    , such as muscle fibre type composition and power reserve, relate to endurance time. Twenty males underwent testing to determine their maximal oxygen uptake (VO(2max)), power output corresponding to 90% of VO(2max) at 80 rpm (W90), FCPR at W90, percentage of slow twitch muscle fibres (% MHC I), maximal leg power...... time was negatively related to VO(2max), W90 and % MHC I, while positively related to power reserve. In conclusion, at group level, endurance time was longer at FCPR and at a pedalling rate 25% lower compared to a pedalling rate 25% higher than FCPR. Further, inter-individual physiological variables......The purpose of this study into high-intensity cycling was to: (1) test the hypothesis that endurance time is longest at a freely chosen pedalling rate (FCPR), compared to pedalling rates 25% lower (FCPR-25) and higher (FCPR+25) than FCPR, and (2) investigate how physiological variables...

  13. Vortex dynamics and shear layer instability in high intensity cyclotrons

    CERN Document Server

    Cerfon, Antoine J

    2016-01-01

    We show that the space charge dynamics of high intensity beams in the plane perpendicular to the magnetic field in cyclotrons is described by the two-dimensional Euler equations for an incompressible fluid. This analogy with fluid dynamics gives a unified and intuitive framework to explain the beam spiraling and beam break up behavior observed in experiments and in simulations. In particular, we demonstrate that beam break up is the result of a classical instability occurring in fluids subject to a sheared flow. We give scaling laws for the instability and predict the nonlinear evolution of beams subject to it. Our work suggests that cyclotrons may be uniquely suited for the experimental study of shear layers and vortex distributions that are not achievable in Penning-Malmberg traps.

  14. High Intensity Beam Issues in the CERN Proton Synchrotron

    CERN Document Server

    Aumon, Sandra; Rivkin, Leonid

    This PhD work is about limitations of high intensity proton beams observed in the CERN Proton Synchrotron (PS) and, in particular, about issues at injection and transition energies. With its 53 years, the CERN PS would have to operate beyond the limit of its performance to match the future requirements. Beam instabilities driven by transverse impedance and aperture restrictions are important issues for the operation and for the High-Luminosity LHC upgrade which foresees an intensity increase delivered by the injectors. The main subject of the thesis concerns the study of a fast transverse instability occurring at transition energy. The proton beams crossing this energy range are particularly sensitive to wake forces because of the slow synchrotron motion. This instability can cause a strong vertical emittance blow-up and severe losses in less than a synchrotron period. Experimental observations show that the particles at the peak density of the beam longitudinal distribution oscillate in the vertical plane du...

  15. Increased collection efficiency of LIFI high intensity electrodeless light source

    Science.gov (United States)

    Hafidi, Abdeslam; DeVincentis, Marc; Duelli, Markus; Gilliard, Richard

    2008-02-01

    Recently, RF driven electrodeless high intensity light sources have been implemented successfully in the projection display systems for HDTV and videowall applications. This paper presents advances made in the RF waveguide and electric field concentrator structures with the purpose of reducing effective arc size and increasing light collection. In addition, new optical designs are described that further improve system efficiency. The results of this work demonstrate that projection system light throughput is increased relative to previous implementations and performance is optimized for home theater and other front projector applications that maintain multi-year lifetime without re-lamping, complete spectral range, fast start times and high levels of dynamic contrast due to dimming flexibility in the light source system.

  16. Simplified shielding calculation system for high-intensity proton accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Masumura, Tomomi; Nakashima, Hiroshi; Nakane, Yoshihiro; Sasamoto, Nobuo [Center for Neutron Science, Tokai Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan)

    2000-06-01

    A simplified shielding calculation system is developed for applying conceptual shielding design of facilities in the joint project for high-intensity proton accelerators. The system is composed of neutron transmission calculation part for bulk shielding using simplified formulas: Moyer model and Tesch's formula, and neutron skyshine calculation part using an empirical formula: Stapleton's formula. The system is made with the Microsoft Excel software for user's convenience. This report provides a manual for the system as well as calculation conditions used in the calculation such as Moyer model's parameters. In this report preliminary results based on data at December 8, 1999, are also shown as an example. (author)

  17. Repeated high-intensity exercise in a professional rugby league.

    Science.gov (United States)

    Austin, Damien J; Gabbett, Tim J; Jenkins, David J

    2011-07-01

    The primary aim of this study was to identify and describe the frequency and duration of repeated high-intensity exercise (RHIE) bouts in Australian professional rugby league (National Rugby League) and whether these occurred at critical times during a game. Time motion analysis was used during 5 competition matches; 1 player from 3 positional groups (hit-up forward, adjustable, and outside back) was analyzed in each match. The ranges of RHIE bouts for the 3 positional groups were hit-up forwards 9-17, adjustables 2-8, and outside backs 3-7. Hit-up forwards were involved in a significantly greater number of RHIE bouts (p rugby league players are likely to encounter.

  18. Raman forward scattering of high-intensity chirped laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, C.B.; Esarey, E.; Shadwick, B.A.; Leemans, W.P.

    2002-06-23

    Raman forward scattering of a high-intensity, short-duration, frequency-chirped laser pulse propagating in an underdense plasma is examined. The growth of the direct forward scattered light is calculated for a laser pulse with a linear frequency chirp in various spatio-temporal regimes. This includes a previously undescribed regime of strongly-coupled four-wave nonresonant interaction, which is important for relativistic laser intensities. In all regimes of forward scattering, it is shown that the growth rate increases (decreases) for positive (negative) frequency chirp. The effect of chirp on the growth rate is relatively minor, i.e., a few percent chirp yields few percent changes in the growth rates. Relation of these results to recent experiments is discussed.

  19. High intensity ion beams in rf undulator linac

    Directory of Open Access Journals (Sweden)

    E. S. Masunov

    2008-07-01

    Full Text Available The possibility of using a radio frequency undulator field to accelerate a high intensity ion beam in a linac is discussed. Such an accelerator can be realized using the periodical interdigital H-type resonator structure. The accelerating force is produced by an electric field which is a combination of two or more spatial harmonics, none of them being synchronous with the ion beam. The value of this force is proportional to the squared charge. The equations of motion in Hamiltonian form are derived by means of smooth approximation. The analysis of the 3D effective potential function allows finding the conditions of the beam focusing and acceleration. Two ways to increase ion beam intensity are considered: (i to enlarge beam cross section; (ii to neutralize the beam space charge by accelerating ions with opposite charge signs within the same bunch. The basic results are confirmed by a numerical simulation.

  20. Fermilab main injector: High intensity operation and beam loss control

    Science.gov (United States)

    Brown, Bruce C.; Adamson, Philip; Capista, David; Chou, Weiren; Kourbanis, Ioanis; Morris, Denton K.; Seiya, Kiyomi; Wu, Guan Hong; Yang, Ming-Jen

    2013-07-01

    From 2005 through 2012, the Fermilab Main Injector provided intense beams of 120 GeV protons to produce neutrino beams and antiprotons. Hardware improvements in conjunction with improved diagnostics allowed the system to reach sustained operation at 400 kW beam power. Transmission was very high except for beam lost at or near the 8 GeV injection energy where 95% beam transmission results in about 1.5 kW of beam loss. By minimizing and localizing loss, residual radiation levels fell while beam power was doubled. Lost beam was directed to either the collimation system or to the beam abort. Critical apertures were increased while improved instrumentation allowed optimal use of available apertures. We will summarize the improvements required to achieve high intensity, the impact of various loss control tools and the status and trends in residual radiation in the Main Injector.

  1. Fast damping in mismatched high intensity beam transportation

    Directory of Open Access Journals (Sweden)

    V. Variale

    2001-08-01

    Full Text Available A very fast damping of beam envelope oscillation amplitudes was recently observed in simulations of high intensity beam transport, through periodic FODO cells, in mismatched conditions [V. Variale, Nuovo Cimento Soc. Ital. Fis. 112A, 1571–1582 (1999 and T. Clauser et al., in Proceedings of the Particle Accelerator Conference, New York, 1999 (IEEE, Piscataway, NJ, 1999, p. 1779]. A Landau damping mechanism was proposed at the origin of observed effect. In this paper, to further investigate the source of this fast damping, extensive simulations have been carried out. The results presented here support the interpretation of the mechanism at the origin of the fast damping as a Landau damping effect.

  2. Relativistic electron mirrors from high intensity laser nanofoil interactions

    Energy Technology Data Exchange (ETDEWEB)

    Kiefer, Daniel

    2012-12-21

    The reflection of a laser pulse from a mirror moving close to the speed of light could in principle create an X-ray pulse with unprecedented high brightness owing to the increase in photon energy and accompanying temporal compression by a factor of 4γ{sup 2}, where γ is the Lorentz factor of the mirror. While this scheme is theoretically intriguingly simple and was first discussed by A. Einstein more than a century ago, the generation of a relativistic structure which acts as a mirror is demanding in many different aspects. Recently, the interaction of a high intensity laser pulse with a nanometer thin foil has raised great interest as it promises the creation of a dense, attosecond short, relativistic electron bunch capable of forming a mirror structure that scatters counter-propagating light coherently and shifts its frequency to higher photon energies. However, so far, this novel concept has been discussed only in theoretical studies using highly idealized interaction parameters. This thesis investigates the generation of a relativistic electron mirror from a nanometer foil with current state-of-the-art high intensity laser pulses and demonstrates for the first time the reflection from those structures in an experiment. To achieve this result, the electron acceleration from high intensity laser nanometer foil interactions was studied in a series of experiments using three inherently different high power laser systems and free-standing foils as thin as 3nm. A drastic increase in the electron energies was observed when reducing the target thickness from the micrometer to the nanometer scale. Quasi-monoenergetic electron beams were measured for the first time from ultrathin (≤5nm) foils, reaching energies up to ∝35MeV. The acceleration process was studied in simulations well-adapted to the experiments, indicating the transition from plasma to free electron dynamics as the target thickness is reduced to the few nanometer range. The experience gained from those

  3. Semicircular Canal Pressure Changes During High-intensity Acoustic Stimulation.

    Science.gov (United States)

    Maxwell, Anne K; Banakis Hartl, Renee M; Greene, Nathaniel T; Benichoux, Victor; Mattingly, Jameson K; Cass, Stephen P; Tollin, Daniel J

    2017-08-01

    Acoustic stimulation generates measurable sound pressure levels in the semicircular canals. High-intensity acoustic stimuli can cause hearing loss and balance disruptions. To examine the propagation of acoustic stimuli to the vestibular end-organs, we simultaneously measured fluid pressure in the cochlea and semicircular canals during both air- and bone-conducted sound presentation. Five full-cephalic human cadaveric heads were prepared bilaterally with a mastoidectomy and extended facial recess. Vestibular pressures were measured within the superior, lateral, and posterior semicircular canals, and referenced to intracochlear pressure within the scala vestibuli with fiber-optic pressure probes. Pressures were measured concurrently with laser Doppler vibrometry measurements of stapes velocity during stimulation with both air- and bone-conduction. Stimuli were pure tones between 100 Hz and 14 kHz presented with custom closed-field loudspeakers for air-conducted sounds and via commercially available bone-anchored device for bone-conducted sounds. Pressures recorded in the superior, lateral, and posterior semicircular canals in response to sound stimulation were equal to or greater in magnitude than those recorded in the scala vestibuli (up to 20 dB higher). The pressure magnitudes varied across canals in a frequency-dependent manner. High sound pressure levels were recorded in the semicircular canals with sound stimulation, suggesting that similar acoustical energy is transmitted to the semicircular canals and the cochlea. Since these intralabyrinthine pressures exceed intracochlear pressure levels, our results suggest that the vestibular end-organs may also be at risk for injury during exposure to high-intensity acoustic stimuli known to cause trauma in the auditory system.

  4. New Zealand Blackcurrant Extract Improves High-Intensity Intermittent Running.

    Science.gov (United States)

    Perkins, Ian Craig; Vine, Sarah Anne; Blacker, Sam David; Willems, Mark Elisabeth Theodorus

    2015-10-01

    We examined the effect of New Zealand blackcurrant (NZBC) extract on high-intensity intermittent running and postrunning lactate responses. Thirteen active males (age: 25 ± 4 yrs, height: 1.82 ± 0.07 m, body mass: 81 ± 14 kg, VO2max: 56 ± 4 ml·kg-1·min-1, vVO2max: 17.6 ± 0.8 km·h-1) performed a treadmill running protocol to exhaustion, which consisted of stages with 6 × 19 s of sprints with 15 s of low-intensity running between sprints. Interstage rest time was 1 min and stages were repeated with increasing sprint speeds. Subjects consumed capsuled NZBC extract (300 mg·day-1 CurraNZ; containing 105 mg anthocyanin) or placebo for 7 days (double-blind, randomized, crossover design, wash-out at least 14 days). Blood lactate was collected for 30 min postexhaustion. NZBC increased total running distance by 10.6% (NZBC: 4282 ± 833 m, placebo: 3871 ± 622 m, p = .02), with the distance during sprints increased by 10.8% (p = .02). Heart rate, oxygen uptake, lactate and rating of perceived exertion were not different between conditions for the first 4 stages completed by all subjects. At exhaustion, blood lactate tended to be higher for NZBC (NZBC: 6.01 ± 1.07 mmol·L-1, placebo: 5.22 ± 1.52 mmol·L-1, p = .07). There was a trend for larger changes in lactate following 15 min (NZBC: -2.89 ± 0.51 mmol·L-1, placebo: -2.46 ± 0.39 mmol·L-1, p = .07) of passive recovery. New Zealand blackcurrant extract (CurraNZ) may enhance performance in sports characterized by high-intensity intermittent exercise as greater distances were covered with repeated sprints, there was higher lactate at exhaustion, and larger changes in lactate during early recovery after repeated sprints to exhaustion.

  5. Nanobiotechnology promotes noninvasive high-intensity focused ultrasound cancer surgery.

    Science.gov (United States)

    Chen, Yu; Chen, Hangrong; Shi, Jianlin

    2015-01-07

    The successful cancer eradication in a noninvasive manner is the ultimate objective in the fight against cancer. As a "bloodless scalpel," high-intensity focused ultrasound (HIFU) is regarded as one of the most promising and representative noninvasive therapeutic modalities for cancer surgery. However, large-scale clinical applications of HIFU are still in their infancy because of critical efficiency and safety issues which remain to be solved. Fortunately, recently developed nanobiotechnology provides an alternative efficient approach to improve such important issues in HIFU, especially for cancer therapy. This Research News presents the very recent exciting progresses on the elaborate design and fabrication of organic, inorganic, and organic/inorganic hybrid nanoparticles for enhancing the HIFU ablation efficiency against tumor tissues. It is highly expected that this Research News can arouse more extensive research enthusiasm on the development of functional nanomaterials for highly efficient HIFU-based synergistic therapy, which will give a promising noninvasive therapeutic modality for the successful cancer therapy with minimal damage to surrounding normal tissues, due to the noninvasive and site-specific therapeutic features of HIFU.

  6. A review of adolescent high-intensity interval training.

    Science.gov (United States)

    Logan, Greig R M; Harris, Nigel; Duncan, Scott; Schofield, Grant

    2014-08-01

    Despite the promising evidence supporting positive effects of high-intensity interval training (HIIT) on the metabolic profile in adults, there is limited research targeting adolescents. Given the rising burden of chronic disease, it is essential to implement strategies to improve the cardiometabolic health in adolescence, as this is a key stage in the development of healthy lifestyle behaviours. This narrative review summarises evidence of the relative efficacy of HIIT regarding the metabolic health of adolescents. Methodological inconsistencies confound our ability to draw conclusions; however, there is meaningful evidence supporting HIIT as a potentially efficacious exercise modality for use in the adolescent cohort. Future research must examine the effects of various HIIT protocols to determine the optimum strategy to deliver cardiometabolic health benefits. Researchers should explicitly show between-group differences for HIIT intervention and steady-state exercise or control groups, as the magnitude of difference between HIIT and other exercise modalities is of key interest to public health. There is scope for research to examine the palatability of HIIT as an exercise modality for adolescents through investigating perceived enjoyment during and after HIIT, and consequent long-term exercise adherence.

  7. Longitudinal tracking studies for a high intensity proton synchrotron

    Energy Technology Data Exchange (ETDEWEB)

    Lessner, E.; Cho, Y.; Harkay, K.; Symon, K. [Argonne National Laboratory, 9700 Cass Ave., Argonne, Illinois 60439 (United States)

    1996-06-01

    Results from longitudinal tracking studies for a high intensity proton synchrotron designed for a 1-MW spallation source are presented. The machine delivers a proton beam of 0.5 mA time-averaged current at a repetition rate of 30 Hz. The accelerator is designed to have radiation levels that allow hands-on-maintenance. However, the high beam intensity causes strong space charge fields whose effects may lead to particle loss and longitudinal instabilities. The space charge fields modify the particle distribution, distort the stable bucket area and reduce the rf linear restoring force. Tracking simulations were conducted to analyze the space charge effects on the dynamics of the injection and acceleration processes and means to circumvent them. The tracking studies led to the establishment of the injected beam parameters and rf voltage program that minimized beam loss and longitudinal instabilities. Similar studies for a 10-GeV synchrotron that uses the 2-GeV synchrotron as its injector are also discussed. {copyright} {ital 1996 American Institute of Physics.}

  8. Formation of a high intensity low energy positron string

    Science.gov (United States)

    Donets, E. D.; Donets, E. E.; Syresin, E. M.; Itahashi, T.; Dubinov, A. E.

    2004-05-01

    The possibility of a high intensity low energy positron beam production is discussed. The proposed Positron String Trap (PST) is based on the principles and technology of the Electron String Ion Source (ESIS) developed in JINR during the last decade. A linear version of ESIS has been used successfully for the production of intense highly charged ion beams of various elements. Now the Tubular Electron String Ion Source (TESIS) concept is under study and this opens really new promising possibilities in physics and technology. In this report, we discuss the application of the tubular-type trap for the storage of positrons cooled to the cryogenic temperatures of 0.05 meV. It is intended that the positron flux at the energy of 1-5 eV, produced by the external source, is injected into the Tubular Positron Trap which has a similar construction as the TESIS. Then the low energy positrons are captured in the PST Penning trap and are cooled down because of their synchrotron radiation in the strong (5-10 T) applied magnetic field. It is expected that the proposed PST should permit storing and cooling to cryogenic temperature of up to 5×109 positrons. The accumulated cooled positrons can be used further for various physics applications, for example, antihydrogen production.

  9. High intensity ultrasound modified ovalbumin: Structure, interface and gelation properties.

    Science.gov (United States)

    Xiong, Wenfei; Wang, Yuntao; Zhang, Chunlan; Wan, Jiawei; Shah, Bakht Ramin; Pei, Yaqiong; Zhou, Bin; Li, Jin; Li, Bin

    2016-07-01

    Influence of high intensity ultrasound (HIUS) on the structure and properties of ovalbumin (OVA) were investigated. It was found that the subunits and secondary structure of OVA did not change significantly with HIUS treatment from the electrophoretic patterns and circular dichroism (CD) spectrum. The amount of free sulfhydryl groups increased and intrinsic fluorescence spectra analysis indicated changes in the tertiary structure and partial unfold of OVA after sonication increased. Compared with the untreated OVA, HIUS treatment increased the emulsifying activity and foaming ability, and decreased interface tension (oil-water and air-water interface), which due to the increased surface hydrophobicity and decreased the surface net charge in OVA, while the emulsifying and foaming stability had no remarkable differences. The increased particle size may be attributed to formation of protein aggregates. Moreover, the gelation temperatures of HIUS-treated samples were higher than the untreated OVA according to the temperature sweep model rheology, and this effect was consistent with the increased in surface hydrophobicity for ultrasound treated OVA. These changes in functional properties of OVA would promote its application in food industry. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Echinococcus granulosus: protoscolicidal effect of high intensity focused ultrasound.

    Science.gov (United States)

    Zou, Xiaoyi; Wang, Junan; Zhao, Hailong; Zhang, Jing; Wu, Weihua; Ye, Bin

    2009-04-01

    High intensity focused ultrasound (HIFU) is a new non-invasive technique which can cause cell death and tissue necrosis by focusing high-energy ultrasonic waves on a single location. The aim of our work is to investigate the damaging effect of HIFU on Echinococcus granulosus protoscolices, as well as its inhibitory effect on growth of hydatid cysts derived from protoscolices. The damaging effect of HIFU on protoscolices was investigated by following parasite mortality after irradiation, while the inhibitory effect was investigated by infection experiments in vivo. The results demonstrated that HIFU was able to damage protoscolices and the protoscolicidal effect was dose-dependent and showed late-onset. The growth of protoscolices that survived the exposure to HIFU was obviously suppressed in vitro, and the mean weight of hydatid cysts resulting from such protoscolices in the experimental group was less than that in controls. Evidences including the protoscolicidal effect, fragmentized protoscolices and low post exposure temperatures, suggest that cavitation may contribute to the protoscolicidal effect of HIFU. In addition, the structure of the germinal membrane in cysts developing from the irradiated protoscolices was not as normal or intact as that from non-irradiated ones, and morphological changes related to degeneration were observed, suggesting that HIFU could prevent protoscolices from developing normal germinal membrane and consequently stop the proliferation of secondary hydatid cysts. HIFU demonstrated damaging effect on protoscolices, inhibited the growth of protoscolices in vitro and in vivo, and could be a possible therapeutic option for cystic echinococcosis.

  11. Treatment of glaucoma with high intensity focused ultrasound.

    Science.gov (United States)

    Aptel, Florent; Lafon, Cyril

    2015-05-01

    Glaucoma is a common disease mainly due to an increase in pressure inside the eye, leading to a progressive destruction of the optic nerve, potentially to blindness. Intraocular pressure (IOP) is the result of a balance between production of liquid that fills the eye--aqueous humour--and its resorption. All treatments for glaucoma aim to reduce IOP and can therefore have two mechanisms of action: reducing aqueous humour production by the partial destruction or medical inhibition of the ciliary body--the anatomical structure responsible for production of aqueous humour--or facilitating the evacuation of aqueous humour from the eye. Several physical methods can be used to destroy the ciliary body, e.g. laser, cryotherapy, microwave. All these methods have two major drawbacks: they are non-selective for the organ to be treated and they have an unpredictable dose–effect relationship. High intensity focused ultrasound (HIFU) can be used to coagulate the ciliary body and avoid these drawbacks. A commercially available device was marketed in the 1980s, but later abandoned, essentially for technical reasons. A smaller circular device using miniaturised transducers was recently developed and proposed for clinical practice. Experimental studies have shown selective coagulation necrosis of the treated ciliary body. The first three clinical trials in humans have shown that this device was well tolerated and allowed a significant, predictable and sustained reduction of IOP. The aim of this contribution is to present a summary of the work concerning the use of HIFU to treat glaucoma.

  12. High Intensity Focused Ultrasound Tumor Therapy System and Its Application

    Science.gov (United States)

    Sun, Fucheng; He, Ye; Li, Rui

    2007-05-01

    At the end of last century, a High Intensity Focused Ultrasound (HIFU) tumor therapy system was successfully developed and manufactured in China, which has been already applied to clinical therapy. This article aims to discuss the HIFU therapy system and its application. Detailed research includes the following: power amplifiers for high-power ultrasound, ultrasound transducers with large apertures, accurate 3-D mechanical drives, a software control system (both high-voltage control and low-voltage control), and the B-mode ultrasonic diagnostic equipment used for treatment monitoring. Research on the dosage of ultrasound required for tumour therapy in multiple human cases has made it possible to relate a dosage formula, presented in this paper, to other significant parameters such as the volume of thermal tumor solidification, the acoustic intensity (I), and the ultrasound emission time (tn). Moreover, the HIFU therapy system can be applied to the clinical treatment of both benign and malignant tumors in the pelvic and abdominal cavity, such as uterine fibroids, liver cancer and pancreatic carcinoma.

  13. High-intensity positron microprobe at Jefferson Lab

    CERN Document Server

    Golge, Serkan; Wojtsekhowski, Bogdan

    2014-01-01

    We present a conceptual design for a novel continuous wave electron-linac based high-intensity slow-positron production source with a projected intensity on the order of 10$^{10}$ e$^+$/s. Reaching this intensity in our design relies on the transport of positrons (T$_+$ below 600 keV) from the electron-positron pair production converter target to a low-radiation and low-temperature area for moderation in a high-efficiency cryogenic rare gas moderator, solid Ne. The performance of the integrated beamline has been verified through computational studies. The computational results include Monte Carlo calculations of the optimized electron/positron beam energies, converter target thickness, synchronized raster system, transport of the beam from the converter target to the moderator, extraction of the beam from the channel, and moderation efficiency calculations. For the extraction of positrons from the magnetic channel a magnetic field terminator plug prototype has been built and experimental data on the effective...

  14. Blood coagulation using High Intensity Focused Ultrasound (HIFU)

    Science.gov (United States)

    Nguyen, Phuc V.; Oh, Junghwan; Kang, Hyun Wook

    2014-03-01

    High Intensity Focused Ultrasound (HIFU) technology provides a feasible method of achieving thermal coagulation during surgical procedures. One of the potential clinical benefits of HIFU can induce immediate hemostasis without suturing. The objective of this study was to investigate the efficiency of a HIFU system for blood coagulation on severe vascular injury. ngHIFU treatment was implemented immediately after bleeding in artery. The ultrasound probe was made of piezoelectric material, generating a central frequency of 2.0 MHz as well as an ellipsoidal focal spot of 2 mm in lateral dimension and 10 mm in axial dimension. Acoustic coagulation was employed on a perfused chicken artery model in vitro. A surgical incision (1 to 2 mm long) was made with a scapel on the arterial wall, and heparinized autologous blood was made to leak out from the incision with a syringe pump. A total of 5 femoral artery incisions was treated with the HIFU beam. The intensity of 4500 W/cm2 at the focus was applied for all treatments. Complete hemostasis was achieved in all treatments, along with the treatment times of 25 to 50 seconds. The estimated intraoperative blood loss was from 2 to 5 mL. The proposed HIFU system may provide an effective method for immediate blood coagulation for arteries and veins in clinical applications.

  15. Robotic Assisted Laparoscopic Prostatectomy after High Intensity Focused Ultrasound Failure

    Directory of Open Access Journals (Sweden)

    Leon Telis

    2017-01-01

    Full Text Available Background. Prostate cancer is the most common cancer diagnosed in men. As new focal therapies become more popular in treatment of prostate cancer, failure cases requiring salvage therapy with either surgical or other techniques are being reported. Objective. To report the options in treatment of prostate cancer after recurrence or failure of the primary treatment modality. Methods. We report a salvage robotic assisted laparoscopic radical prostatectomy (RALP for prostate cancer recurrence following high intensity focused ultrasound treatment (HIFU in the United States. Results. A 67-year-old man who underwent HIFU treatment for prostate adenocarcinoma 2 years prior was presented with a rising prostate specific antigen of 6.1 ng/mL to our clinic. A biopsy proven recurrent disease in the area of previous treatment documented the failure of treatment. The patient elected to undergo a salvage RALP. The operation time was 159 minutes. The patient was discharged from the hospital on postoperative day 1 with no complications. The catheter was removed on post-op day 10. The patient reserved sexual function and urinary continence. The PSA levels on 6 months’ follow-up are undetectable. Conclusions. Salvage RALP is an effective and safe treatment choice for recurrent prostate adenocarcinoma following failed HIFU treatment if operated by an experienced surgeon.

  16. Bunching high intensity proton beams with a CH-DTL

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, Malte; Claessens, Christine; Heilmann, Manuel; Hinrichs, Ole; Koser, Daniel; Meusel, Oliver; Noll, Daniel; Podlech, Holger; Ratzinger, Ulrich; Seibel, Anja [Institut fuer Angewandte Physik, Goethe-Universitaet Frankfurt am Main (Germany)

    2014-07-01

    The Frankfurt Neutron Source at the Stern-Gerlach-Zentrum (FRANZ) will provide ultra short neutron pulses at high intensities and repetition rates. The facility is under construction with an expected first beam by the end of 2014. A 5-Gap CH rebuncher is installed behind a coupled RFQ/IH-DTL combination at the end of the LINAC section between two magnetic quadrupole triplets. It will be used for varying the final energy between 1.8 and 2.2 MeV, as well as for focusing the proton beam bunch longitudinally, to compensate RF defocusing effects and huge space charge forces at currents up to 200 mA at the final stage of extension. Therefore high current beam dynamic simulations are in progress. They include benchmarking of different beam dynamic codes like LORASR, TraceWin and Bender (a new PIC tracking code developed at IAP), as well as validating the results by measurements. Detailed error tolerance studies, thermal simulations and examination of multipole field impact, due to the cavity geometry, are also done. Furthermore, this CH rebuncher serves as prototype for CH cavity operation at MYRRHA (Belgium), an Accelerator Driven System (ADS) for transmutation of high level nuclear waste. After copper-plating the cavity, RF conditioning will start in spring 2014.

  17. Creatine kinase response to high-intensity aerobic exercise in adult-onset muscular dystrophy

    DEFF Research Database (Denmark)

    Andersen, Søren P; Sveen, Marie-Louise; Hansen, Regitze S

    2013-01-01

    We investigated the effect of high-intensity exercise on plasma creatine kinase (CK) in patients with muscular dystrophies.......We investigated the effect of high-intensity exercise on plasma creatine kinase (CK) in patients with muscular dystrophies....

  18. Inelastic scattering in condensed matter with high intensity Moessbauer radiation

    Energy Technology Data Exchange (ETDEWEB)

    Yelon, W.B.; Schupp, G.

    1990-10-01

    We give a progress report for the work which has been carried out in the last three years with DOE support. A facility for high-intensity Moessbauer scattering is now fully operational at the University of Missouri Research Reactor (MURR) as well as facility at Purdue, using special isotopes produced at MURR. High precision, fundamental Moessbauer effect studies have been carried out using scattering to filter the unwanted radiation. These have led to a new Fourier transform method for describing Moessbauer effect (ME) lineshape and a direct method of fitting ME data to the convolution integral. These methods allow complete correction for source resonance self absorption (SRSA) and the accurate representation of interference effects that add an asymmetric component to the ME lines. We have begun applying these techniques to attenuated ME sources whose central peak has been attenuated by stationary resonant absorbers, to more precisely determine interference parameters and line-shape behavior in the resonance asymptotic region. This analysis is important to both the fundamental ME studies and to scattering studies for which a deconvolution is essential for extracting the correct recoilless fractions and interference parameters. A number of scattering studies have been successfully carried out including a study of the thermal diffuse scattering in Si, which led to an analysis of the resolution function for gamma-ray scattering. Also studied was the anharmonic motion in Na and the satellite reflection Debye-Waller factor in TaS{sub 2}, which indicate phason rather than phonon behavior. We have begun quasielastic diffusion studies in viscous liquids and current results are summarized. These advances, coupled to our improvements in MIcrofoil Conversion Electron spectroscopy lay the foundation for the proposed research outlined in this request for a three-year renewal of DOE support.

  19. Gamma scattering in condensed matter with high intensity Moessbauer radiation

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    We give a progress report for the work which has been carried out in the last three years with DOE support. A facility for high-intensity Moessbauer scattering is now fully operational at the University of Missouri Research Reactor (MURR) as well as a facility at Purdue, using special isotopes produced at MURR. High precision, fundamental Moessbauer effect studies have been carried out using scattering to filter the unwanted radiation. These have led to a new Fourier transform method for describing Moessbauer effect (ME) lineshape and a direct method of fitting ME data to the convolution integral. These methods allow complete correction for source resonance self absorption (SRSA) and the accurate representation of interference effects that add an asymmetric component to the ME lines. We have begun applying these techniques to attenuated ME sources whose central peak has been attenuated by stationary resonant absorbers, to more precisely determine interference parameters and line-shape behavior in the resonance asymptotic region. This analysis is important to both the fundamental ME studies and to scattering studies for which a deconvolution is essential for extracting the correct recoilless fractions and interference parameters. A number of scattering studies have been successfully carried out including a study of the thermal diffuse scattering in Si, which led to an analysis of the resolution function for gamma-ray scattering. Also studied was the anharmonic motion in Na and the satellite reflection Debye-Waller factor in TaS{sub 2}, which indicate phason rather than phonon behavior. We have begun quasielastic diffusion studies in viscous liquids and current results are summarized. These advances, coupled to our improvements in MIcrofoil Conversion Electron spectroscopy lay the foundation for the proposed research outlined in this request for a three-year renewal of DOE support.

  20. Compliance with High-Intensity Radiated Fields Regulations - Emitter's Perspective

    Science.gov (United States)

    Statman, Joseph; Jamnejad, Vahraz; Nguyen, Lee

    2012-01-01

    NASA's Deep Space Network (DSN) uses high-power transmitters on its large antennas to communicate with spacecraft of NASA and its partner agencies. The prime reflectors of the DSN antennas are parabolic, at 34m and 70m in diameter. The DSN transmitters radiate Continuous Wave (CW) signals at 20 kW - 500 kW at X-band and S-band frequencies. The combination of antenna reflector size and high frequency results in a very narrow beam with extensive oscillating near-field pattern. Another unique feature of the DSN antennas is that they (and the radiated beam) move mostly at very slow sidereal rate, essentially identical in magnitude and at the opposite direction of Earth rotation.The DSN is in the process of revamping its documentation to provide analysis of the High Intensity Radiation Fields (HIRF) environment resulting from radio frequency radiation from DSN antennas for comparison to FAA regulations regarding certification of HIRF protection as outlined in the FAA regulations on HIRF protection for aircraft electrical and electronic systems (Title 14, Code of Federal Regulations (14 CFR) [section sign][section sign] 23.1308, 25.1317, 27.1317, and 29.1317).This paper presents work done at JPL, in consultation with the FAA. The work includes analysis of the radiated field structure created by the unique DSN emitters (combination of transmitters and antennas) and comparing it to the fields defined in the environments in the FAA regulations. The paper identifies areas that required special attention, including the implications of the very narrow beam of the DSN emitters and the sidereal rate motion. The paper derives the maximum emitter power allowed without mitigation and the mitigation zones, where required.Finally, the paper presents summary of the results of the analyses of the DSN emitters and the resulting DSN process documentation.

  1. High intensity ultrasound transducer used in gene transfection

    Science.gov (United States)

    Morrison, Kyle P.; Keilman, George W.; Noble, Misty L.; Brayman, Andrew A.; Miao, Carol H.

    2012-11-01

    This paper describes a novel therapeutic high intensity non-focused ultrasound (HIU) transducer designed with uniform pressure distribution to aid in accelerated gene transfer in large animal liver tissues in vivo. The underlying HIU transducer was used to initiate homogeneous cavitation throughout the tissue while delivering up to 2.7 MPa at 1.1 MHz across its radiating surface. The HIU transducer was built into a 6 cm diameter x 1.3 cm tall housing ergonomically designed to avoid collateral damage to the surrounding anatomy during dynamic motion. The ultrasound (US) radiation was applied in a 'paintbrush-like' manner to the surface of the liver. The layers and geometry of the transducer were carefully selected to maximize the active diameter (5.74 cm), maximize the electrical to acoustic conversion efficiency (85%) to achieve 2.7 MPa of peak negative pressure, maximize the frequency operating band at the fundamental resonance to within a power transfer delta of 1 dB, and reduce the pressure delta to within 2 dB across the radiating surface. For maximum peak voltage into the transducer, a high performance piezoceramic was chosen and a DC bias circuit was built integral to the system. An apodized two element annular pattern was made from a single piezoceramic element, resulting in significant pressure uniformity enhancement. In addition to using apodization for pressure uniformity, a proprietary multi-layered structure was used to improve efficiency while sustaining an operating band from 900 kHz to 1.3 MHz. The resultant operating band allowed for dithering techniques using frequency modulation. The underlying HIU transducer for use in large animals enhances gene expression up to 6300-fold.

  2. Outcomes of exertional rhabdomyolysis following high-intensity resistance training.

    Science.gov (United States)

    Huynh, A; Leong, K; Jones, N; Crump, N; Russell, D; Anderson, M; Steinfort, D; Johnson, D F

    2016-05-01

    High-intensity resistance training (HIRT) programmes are increasingly popular amongst personal trainers and those attending gymnasiums. We report the experience of exertional rhabdomyolysis (ER) at two tertiary hospitals in Melbourne, Australia. To compare the clinical outcomes of ER with other causes of rhabdomyolysis. Retrospective cross-sectional study of patients presenting with a serum creatine kinase (CK) of greater than 25 000 units/L from 1 September 2013 to 31 August 2014 at two tertiary referral hospitals in Melbourne, Australia. Records were examined to identify care measures implemented during hospital stay, clinical outcomes during admission and on subsequent follow up. Thirty four cases of rhabdomyolysis with a CK of greater than 25 000 units/L (normal range: 20-180 units/L) were identified during the 12-month study period. Twelve of the 34 cases (35%) had ER with 10 of 12 related to HIRT. No acute kidney injury, intensive care admission or death were seen among those with ER. All cases were managed conservatively, with 11 admitted and 9 receiving intravenous fluids only. In contrast, patients with rhabdomyolysis from other causes experienced significantly higher rates of intensive care admission (64%, P = 0.0002), acute kidney injury (82%, P = 0.0001) and death (27%, P = 0.069). ER resulting from HIRT appears to have a benign course compared with rhabdomyolysis of other aetiologies in patients with a serum CK greater than 25 000 units/L. Conservative management of ER appears to be adequate, although this requires confirmation in future prospective studies. © 2016 Royal Australasian College of Physicians.

  3. HIGH-INTENSITY FOCUSED ULTRASOUND CASTRATION FOR BREAST CANCER PATIENTS

    Institute of Scientific and Technical Information of China (English)

    王书文; 和新盈; 石景森; 赵东利; 李明众; 王诚; 薛文华

    2003-01-01

    Objective: To evaluate the safety and efficacy of external high-intensity focused ultrasound(HIFU) castration for breast cancerous patients after mastectomy if they are at a high risk of recurrence. Methods: We recruited 52 consecutive patients with primary operable breast cancer who were treated with mastectomy with excision of regional lymph nodes. Patients were positive for ER and PR immuno- cytochemical staining, node-positive, un-menopause, over 40 years old and were divided into two groups randomly. For castration, 26 patients received one or two times of HIFU treatment within five days, and the other patients received radiotherapy with DT 18Gy/9 f/11days. During and after the treatment, local changes and systemic response of the patients were observed. Results: After 1 month treatment, levels of serum E1 and E2 were significantly decreased compared to before treatment in HIFU groups (P<0.01 and P<0.001). The same changes were occurred in radiotherapy(RT) groups (P<0.05 and P<0.01). The levels of serum E1 or E2 in RT groups were higher than in HIFU groups (P<0.05). The symptom distribution of 'climacteric syndrome' of HIFU groups were significantly different from RT groups (P<0.01). The follow-up time was 4 months. The incidence of amenorrhea was 100% in all patients. No serious complications were seen. The temperature, pulse, blood pressure, and respiratory rate of the patients were almost normal. Conclusion: We have shown that the use of HIFU in the castrating of patients with breast cancer is feasible, safe and effective. This technology may provide a rapid noninvasive alterative to conventional bilateral oophorectomy or RT castration.

  4. Advanced approaches to high intensity laser-driven ion acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Henig, Andreas

    2010-04-26

    Since the pioneering work that was carried out 10 years ago, the generation of highly energetic ion beams from laser-plasma interactions has been investigated in much detail in the regime of target normal sheath acceleration (TNSA). Creation of ion beams with small longitudinal and transverse emittance and energies extending up to tens of MeV fueled visions of compact, laser-driven ion sources for applications such as ion beam therapy of tumors or fast ignition inertial con finement fusion. However, new pathways are of crucial importance to push the current limits of laser-generated ion beams further towards parameters necessary for those applications. The presented PhD work was intended to develop and explore advanced approaches to high intensity laser-driven ion acceleration that reach beyond TNSA. In this spirit, ion acceleration from two novel target systems was investigated, namely mass-limited microspheres and nm-thin, free-standing diamond-like carbon (DLC) foils. Using such ultrathin foils, a new regime of ion acceleration was found where the laser transfers energy to all electrons located within the focal volume. While for TNSA the accelerating electric field is stationary and ion acceleration is spatially separated from laser absorption into electrons, now a localized longitudinal field enhancement is present that co-propagates with the ions as the accompanying laser pulse pushes the electrons forward. Unprecedented maximum ion energies were obtained, reaching beyond 0.5 GeV for carbon C{sup 6+} and thus exceeding previous TNSA results by about one order of magnitude. When changing the laser polarization to circular, electron heating and expansion were shown to be efficiently suppressed, resulting for the first time in a phase-stable acceleration that is dominated by the laser radiation pressure which led to the observation of a peaked C{sup 6+} spectrum. Compared to quasi-monoenergetic ion beam generation within the TNSA regime, a more than 40 times

  5. Leg vascular and skeletal muscle mitochondrial adaptations to aerobic high-intensity exercise training are enhanced in the early postmenopausal phase

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Egelund, Jon; Mandrup Jensen, Camilla Maria

    2017-01-01

    Exercise training leads to favourable adaptations within skeletal muscle; however, this effect of exercise training may be blunted in postmenopausal women due to the loss of oestrogens. Furthermore, postmenopausal women may have an impaired vascular response to acute exercise. We examined......) years of age were included. Before training, leg blood flow, O2 delivery, O2 uptake, and lactate release during knee-extensor exercise were similar in pre- and postmenopausal women. Exercise training reduced (P heart...... rate during the same absolute workloads in the postmenopausal women. These effects were not detected in the premenopausal women. Quadriceps muscle protein contents of mitochondrial complex II, III, and IV, endothelial nitric oxide synthase (eNOS), cyclooxygenase-1 (COX.1), COX-2, and oestrogen related...

  6. The effect of progressive high-intensity inspiratory muscle training and fixed high-intensity inspiratory muscle training on the asymmetry of diaphragm thickness in stroke patients.

    Science.gov (United States)

    Jung, Ju-Hyeon; Kim, Nan-Soo

    2015-10-01

    [Purpose] This study investigated the effects of progressive load and fixed load high-intensity inspiratory muscle training on the asymmetry of diaphragm thickness in stroke patients. [Subjects] Twenty-one stroke patients were assigned to one of three groups: progressive load high-intensity inspiratory muscle training (n = 8), fixed load high-intensity inspiratory muscle training (n = 6), and controls (n = 7). [Methods] The progressive load and fixed load high-intensity inspiratory muscle training participants undertook an exercise program for 20 minutes, three times weekly, for 6 weeks. After each session, diaphragm thickness was measured using ultrasonography. The diaphragm asymmetry ratio and diaphragm thickening ratio were standardized using a formula. [Results] After intervention, the diaphragm asymmetry ratio significantly differed among the three groups, and the diaphragm asymmetry ratio significantly increased in the control group. A significant increase was identified in the diaphragm thickening ratio within the progressive load and fixed load high-intensity inspiratory muscle training groups. [Conclusion] Progressive load and fixed load high-intensity inspiratory muscle training decreased the asymmetry of diaphragm thickness in stroke patients; this effect, in turn, increased the diaphragm thickening ratio in stroke patients. The two interventions examined here should be selectively applied to individuals in the clinical field.

  7. Causative factors of high intensity areas identified by MRI in the pontine base

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Masaki; Takahashi, Akira [Nagoya Univ. (Japan). Faculty of Medicine; Arahata, Yutaka; Motegi, Yoshimasa

    1994-08-01

    High intensity areas in the pontine base were found more frequently in patients of group A who had multiple supratentorial high intensity areas smaller than 15 mm in size and of group B whose vertebral arteries were asymmetric on MR angiography, as compared to those who had none of the above findings of MRI and MR angiography. The high intensity areas of group A were often found bilaterally in the upper pons and those of group B were present unilaterally in the lower pons. Pontine high intensity areas were found frequently on the same side as the smaller vertebral artery in group B. Periventricular hyperintensity was more severe in group A than than in group B. These results suggest that high intensity lesions in the pontine base may conform with the following conditions: (1) multiple small high intensity areas in the supratentorium due to diffuse arteriosclerosis, and (2) asymmetry of the vertebral arteries inducing hemodynamic disorders. (author).

  8. Max Tech and Beyond: High-Intensity Discharge Lamps

    Energy Technology Data Exchange (ETDEWEB)

    Scholand, Michael

    2012-04-01

    High-intensity discharge (HID) lamps are most often found in industrial and commercial applications, and are the light source of choice in street and area lighting, and sports stadium illumination. HID lamps are produced in three types - mercury vapor (MV), high pressure sodium (HPS) and metal halide (MH). Of these, MV and MH are considered white-light sources (although the MV exhibits poor color rendering) and HPS produces a yellow-orange color light. A fourth lamp, low-pressure sodium (LPS), is not a HID lamp by definition, but it is used in similar applications and thus is often grouped with HID lamps. With the notable exception of MV which is comparatively inefficient and in decline in the US from both a sales and installed stock point of view; HPS, LPS and MH all have efficacies over 100 lumens per watt. The figure below presents the efficacy trends over time for commercially available HID lamps and LPS, starting with MV and LPS in 1930's followed by the development of HPS and MH in the 1960's. In HID lamps, light is generated by creating an electric arc between two electrodes in an arc tube. The particles in the arc are partially ionized, making them electrically conductive, and a light-emitting 'plasma' is created. This arc occurs within the arc tube, which for most HID lamps is enclosed within an evacuated outer bulb that thermally isolates and protects the hot arc tube from the surroundings. Unlike a fluorescent lamp that produces visible light through down-converting UV light with phosphors, the arc itself is the light source in an HID lamp, emitting visible radiation that is characteristic of the elements present in the plasma. Thus, the mixture of elements included in the arc tube is one critical factor determining the quality of the light emitted from the lamp, including its correlated color temperature (CCT) and color rendering index (CRI). Similar to fluorescent lamps, HID lamps require a ballast to start and maintain stable

  9. Max Tech and Beyond: High-Intensity Discharge Lamps

    Energy Technology Data Exchange (ETDEWEB)

    Scholand, Michael

    2012-04-01

    High-intensity discharge (HID) lamps are most often found in industrial and commercial applications, and are the light source of choice in street and area lighting, and sports stadium illumination. HID lamps are produced in three types - mercury vapor (MV), high pressure sodium (HPS) and metal halide (MH). Of these, MV and MH are considered white-light sources (although the MV exhibits poor color rendering) and HPS produces a yellow-orange color light. A fourth lamp, low-pressure sodium (LPS), is not a HID lamp by definition, but it is used in similar applications and thus is often grouped with HID lamps. With the notable exception of MV which is comparatively inefficient and in decline in the US from both a sales and installed stock point of view; HPS, LPS and MH all have efficacies over 100 lumens per watt. The figure below presents the efficacy trends over time for commercially available HID lamps and LPS, starting with MV and LPS in 1930's followed by the development of HPS and MH in the 1960's. In HID lamps, light is generated by creating an electric arc between two electrodes in an arc tube. The particles in the arc are partially ionized, making them electrically conductive, and a light-emitting 'plasma' is created. This arc occurs within the arc tube, which for most HID lamps is enclosed within an evacuated outer bulb that thermally isolates and protects the hot arc tube from the surroundings. Unlike a fluorescent lamp that produces visible light through down-converting UV light with phosphors, the arc itself is the light source in an HID lamp, emitting visible radiation that is characteristic of the elements present in the plasma. Thus, the mixture of elements included in the arc tube is one critical factor determining the quality of the light emitted from the lamp, including its correlated color temperature (CCT) and color rendering index (CRI). Similar to fluorescent lamps, HID lamps require a ballast to start and maintain stable

  10. High-intensity intermittent swimming improves cardiovascular health status for women with mild hypertension

    DEFF Research Database (Denmark)

    Mohr, Magni; Nordsborg, Nikolai Baastrup; Lindenskov, Annika;

    2014-01-01

    To test the hypothesis that high-intensity swim training improves cardiovascular health status in sedentary premenopausal women with mild hypertension, sixty-two women were randomized into high-intensity (n = 21; HIT), moderate-intensity (n = 21; MOD), and control groups (n = 20; CON). HIT...... high-intensity intermittent swimming is an effective training strategy to improve cardiovascular health and physical performance...... in sedentary women with mild hypertension. Adaptations are similar with high- and moderate-intensity training, despite markedly less total time spent and distance covered in the high-intensity group....

  11. Personalized metabolomics for predicting glucose tolerance changes in sedentary women after high-intensity interval training

    National Research Council Canada - National Science Library

    Kuehnbaum, Naomi L; Gillen, Jenna B; Gibala, Martin J; Britz-McKibbin, Philip

    2014-01-01

    High-intensity interval training (HIIT) offers a practical approach for enhancing cardiorespiratory fitness, however its role in improving glucose regulation among sedentary yet normoglycemic women remains unclear...

  12. Nakagami imaging for detecting thermal lesions induced by high-intensity focused ultrasound in tissue.

    Science.gov (United States)

    Rangraz, Parisa; Behnam, Hamid; Tavakkoli, Jahan

    2014-01-01

    High-intensity focused ultrasound induces focalized tissue coagulation by increasing the tissue temperature in a tight focal region. Several methods have been proposed to monitor high-intensity focused ultrasound-induced thermal lesions. Currently, ultrasound imaging techniques that are clinically used for monitoring high-intensity focused ultrasound treatment are standard pulse-echo B-mode ultrasound imaging, ultrasound temperature estimation, and elastography-based methods. On the contrary, the efficacy of two-dimensional Nakagami parametric imaging based on the distribution of the ultrasound backscattered signals to quantify properties of soft tissue has recently been evaluated. In this study, ultrasound radio frequency echo signals from ex vivo tissue samples were acquired before and after high-intensity focused ultrasound exposures and then their Nakagami parameter and scaling parameter of Nakagami distribution were estimated. These parameters were used to detect high-intensity focused ultrasound-induced thermal lesions. Also, the effects of changing the acoustic power of the high-intensity focused ultrasound transducer on the Nakagami parameters were studied. The results obtained suggest that the Nakagami distribution's scaling and Nakagami parameters can effectively be used to detect high-intensity focused ultrasound-induced thermal lesions in tissue ex vivo. These parameters can also be used to understand the degree of change in tissue caused by high-intensity focused ultrasound exposures, which could be interpreted as a measure of degree of variability in scatterer concentration in various parts of the high-intensity focused ultrasound lesion.

  13. Muscle damage and adaptation after the second bout of eccentric exercise of the knee extensors.

    Science.gov (United States)

    Hassan, E S

    2014-10-01

    This study examined the muscles ability to adapt to eccentric exercise by the changes in serum myoglobin (Mb), creatine kinase (CK) activity and muscle soreness. The study involved 54 healthy young men from the 23± 2yr age group. These were distributed as subjects for three types of experiments with 18 men in each. Subjects performed 300 maximal eccentric exercises. In experiment I, after performing the first bout of exercise, they were split into three subgroups to perform the second bout after a period of 4, 6, and 8 weeks (WK), respectively. In experiment II, performed the second exercise after a period of 2, 3, and 5 wk, respectively. In experiment III, they performed four exercise bouts spaced 1 wk apart. in experiment II a significant (Pexercise bout 2. In experiment III, serum CK, Mb and muscle soreness responses were highest following bout 1. It was concluded that performance of a single exercise bout had a prophylactic effect on muscle soreness and serum protein responses that lasts approximately 2 wk, with the greatest adaptation occurring after one bout.

  14. Low-intensity eccentric contractions of the knee extensors and flexors protect against muscle damage.

    Science.gov (United States)

    Lin, Min-Ju; Chen, Trevor Chung-Ching; Chen, Hsin-Lian; Wu, Bo-Han; Nosaka, Kazunori

    2015-10-01

    This study investigated the magnitude and duration of the protective effect of low-intensity eccentric contractions (LowEC) against damage induced by maximal eccentric contractions (MaxEC) of the knee flexors (KF) and extensors (KE). Young men were assigned to 8 experimental groups and 2 control groups (n = 13/group); the experimental groups performed LowEC of KF or KE 2 days (2d), 1 week (1wk), 2 weeks (2wk), or 3 weeks (3wk) before MaxEC, while the control groups performed MaxEC of KF or KE without LowEC. The 2d, 1wk, 2wk, and 3wk groups performed 30 LowEC of KF or 60 LowEC of KE with a load of 10% of maximal voluntary isometric contraction strength on a resistance-training machine, and all groups performed 30 MaxEC of KF or 60 MaxEC of KE on an isokinetic dynamometer. Several muscle damage markers were measured from before to 2 days after exercise (LowEC) or from before to 5 days after exercise (MaxEC). No significant changes in any variables were evident after LowEC. The changes in all variables after MaxEC were smaller (P < 0.05) for the 2d and 1wk groups (e.g., peak creatine kinase activity: 1002 ± 501 IU/L; peak muscle soreness: 13 ± 5 mm) than for the control group (peak creatine kinase activity: 3005 ± 983 IU/L; peak muscle soreness 28 ± 6 mm) for both KE and KF. There were no significant differences between the 2d and 1wk groups or among the 2wk, 3wk, and control groups. These results show that LowEC provided 30%-66% protection against damage induced by MaxEC of KF and KE, and the protective effect lasted 1 week.

  15. Knee Extensor and Flexor Torque Development with Concentric and Eccentric Isokinetic Training

    Science.gov (United States)

    Miller, Larry E.; Pierson, Lee M.; Nickols-Richardson, Sharon M.; Wootten, David F.; Selmon, Serah E.; Ramp, Warren K.; Herbert, William G.

    2006-01-01

    This study assessed muscular torque and rate of torque development following concentric (CON) or eccentric (ECC) isokinetic training. Thirty-eight women were randomly assigned to either CON or ECC training groups. Training consisted of knee extension and flexion of the nondominant leg three times per week for 20 weeks (SD = 1). Eccentric training…

  16. Muscle protein degradation and amino acid metabolism during prolonged knee-extensor exercise in humans

    DEFF Research Database (Denmark)

    Van Hall, Gerrit; Saltin, B; Wagenmakers, A J

    1999-01-01

    to a substantial increase in net muscle protein degradation, and that a lowering of the starting muscle glycogen content leads to a further increase. The carbon atoms of the branched-chain amino acids (BCAA), glutamate, aspartate and asparagine, liberated by protein degradation, and the BCAA and glutamate...

  17. Relationship between muscle volume and contractile properties of the human knee extensors.

    Science.gov (United States)

    Behrens, Martin; Brown, Niklas; Bollinger, Robert; Bubeck, Dieter; Mau-Moeller, Anett; Weippert, Matthias; Zschorlich, Volker; Bruhn, Sven; Alt, Wilfried

    2016-01-01

    The present study was designed to investigate the relationship between volume and electrically evoked twitch properties of the quadriceps muscle. Supramaximal single and doublet stimulation of the femoral nerve was used to assess contractile properties at 45° and 80° knee flexion. Muscle volume was measured using a 1.5-Tesla magnetic resonance imaging scanner. Quadriceps muscle volume was only significantly correlated (r = 0.629) with peak twitch torque induced by doublet stimulation at 80° but not at 45° knee flexion.

  18. Knee Extensor and Flexor Torque Development with Concentric and Eccentric Isokinetic Training

    Science.gov (United States)

    Miller, Larry E.; Pierson, Lee M.; Nickols-Richardson, Sharon M.; Wootten, David F.; Selmon, Serah E.; Ramp, Warren K.; Herbert, William G.

    2006-01-01

    This study assessed muscular torque and rate of torque development following concentric (CON) or eccentric (ECC) isokinetic training. Thirty-eight women were randomly assigned to either CON or ECC training groups. Training consisted of knee extension and flexion of the nondominant leg three times per week for 20 weeks (SD = 1). Eccentric training…

  19. ALTERATION OF MUSCLE FUNCTION AFTER ELECTRICAL STIMULATION BOUT OF KNEE EXTENSORS AND FLEXORS

    Directory of Open Access Journals (Sweden)

    Marc Vanderthommen

    2012-12-01

    Full Text Available The purpose was to study the effects on muscle function of an electrical stimulation bout applied unilaterally on thigh muscles in healthy male volunteers. One group (ES group, n = 10 received consecutively 100 isometric contractions of quadriceps and 100 isometric contractions of hamstrings (on-off ratio 6-6 s induced by neuromuscular electrical stimulations (NMES. Changes in muscle torque, muscle soreness (0-10 VAS, muscle stiffness and serum creatine kinase (CK activity were assessed before the NMES exercise (pre-ex as well as 24h (d+1, 48h (d+2 and 120h (d+5 after the bout. A second group (control group, n = 10 were submitted to the same test battery than the ES group and with the same time-frame. The between-group comparison indicated a significant increase in VAS scores and in serum levels of CK only in the ES group. In the ES group, changes were more pronounced in hamstrings than in quadriceps and peaked at d+2 (quadriceps VAS scores = 2.20 ± 1.55 a.u. (0 at pre-ex; hamstrings VAS scores = 3.15 ± 2.14 a.u. (0 at pre-ex; hip flexion angle = 62 ± 5° (75 ± 6° at pre-ex; CK activity = 3021 ± 2693 IU·l-1 (136 ± 50 IU·l-1 at pre-ex. The results of the present study suggested the occurrence of muscle damage that could have been induced by the peculiar muscle recruitment in NMES and the resulting overrated mechanical stress. The sensitivity to the damaging effects of NMES appeared higher in the hamstrings than in quadriceps muscles

  20. Downhill walking training with and without exercise-induced muscle damage similarly increase knee extensor strength.

    Science.gov (United States)

    Maeo, Sumiaki; Yamamoto, Masayoshi; Kanehisa, Hiroaki

    2016-11-01

    This study examined whether avoiding or experiencing exercise-induced muscle damage (EIMD) influences strength gain after downhill walking training. Healthy young males performed treadmill downhill walking (gradient: -28%, velocity: 5 km · h(-1) and load: 10% of body mass) 1 session per week for four weeks using either a ramp-up protocol (n = 16), where exercise duration was gradually increased from 10 to 30, 50 and 70 min over four sessions, or a constant protocol (n = 14), where exercise duration was 40 min for all four sessions. Indirect markers of EIMD were measured throughout the training period. Maximal knee extension torque in eccentric (-1.05 rad·s(-1)), isometric and concentric (1.05 rad·s(-1)) conditions were measured at pre- and post-training. The ramp-up group showed no indications of EIMD throughout the training period (e.g., plasma creatine kinase (CK) activity: always <185 U · L(-1)) while EIMD was evident after the first session in the constant group (CK: peak 485 U · L(-1)). Both groups significantly increased maximal knee extension torque in all conditions with greater gains in eccentric (ramp-up: +19%, constant: +21%) than isometric (+16%, +15%) and concentric (+12%, +10%) strength without any significant group-difference. The current results suggest that EIMD can be avoided by the ramp-up protocol and is not a major determinant of training-induced strength gain.

  1. DIFFERENCES IN BIOMECHANICAL PROPERTIES OF KNEE EXTENSOR REBOUND WITH THE DIFFERENT SURFACE ELASTICITY

    Directory of Open Access Journals (Sweden)

    Katarina Herodek

    2013-07-01

    Full Text Available The sample includes 40 subjects of both sexes: male (20 and female (20 population of students of the Faculty of Sport and Physical Education, University of Nis. The research involves the application of the rebound in gymnastics with two different heights (40 and 50cm on three different surfaces of elasticity: hard, demyelastic and elastic surface. The subject of the research were the dynamic parameters of movement laid down from Drop Jump (DJ with Myotest device and in the following parameters: height (in cm, power (in W/ kg, force (in N/ kg and speed (cm/ s. Using canonical-discrimination analysis showed no statistically significant differences in the performance jump of hard and demyelastic surface from a height 40 cm and 50 cm for men and women, thethe studied parameters (height, strength ,power and speed of the bounce . Revealed a statistically significant difference in performance with the elastic rebound surface elevations of 40 cm and 50 cm for men and women (p = 0.00. Of the examined parameters was obtained that there are significant differences in the Force reflection to the significance level of 98% (0.0255 and the power of reflection on the significance level of 100% (0.0009 in men. In women of the examined parameters was obtained a statistically significant difference in the strength of the rebound only from positions of 40cm and 50cm and 100% (0.0075.

  2. Explosive Strength of the Knee Extensors: The Influence of Criterion Trial Detection Methodology on Measurement Reproducibility

    Directory of Open Access Journals (Sweden)

    Dirnberger Johannes

    2016-04-01

    Full Text Available The present study was conducted to assess test-retest reproducibility of explosive strength measurements during single-joint isometric knee extension using the IsoMed 2000 dynamometer. Thirty-one physically active male subjects (mean age: 23.7 years were measured on two occasions separated by 48–72 h. The intraclass correlation coefficient (ICC 2,1 and the coefficient of variation (CV were calculated for (i maximum torque (MVC, (ii the peak rate of torque development (RTDpeak as well as for (iii the average rate of torque development (RTD and the impulse taken at several predefined time intervals (0–30 to 0–300 ms; thereby explosive strength variables were derived in two conceptually different versions: on the one hand from the MVC-trial (version I, on the other hand from the trial showing the RTDpeak (version II. High ICC-values (0.80–0.99 and acceptable CV-values (1.9–8.7% could be found for MVC as well as for the RTD and the impulse taken at time intervals of ≥100 ms, regardless of whether version I or II was used. In contrast, measurements of the RTDpeak as well as the RTD and the impulse taken during the very early contraction phase (i.e. RTD/impulse0–30ms and RTD/impulse0–50ms showed clearly weaker reproducibility results (ICC: 0.53–0.84; CV: 7.3–16.4% and gave rise to considerable doubts as to clinical usefulness, especially when derived using version I. However, if there is a need to measure explosive strength for earlier time intervals in practice, it is, in view of stronger reproducibility results, recommended to concentrate on measures derived from version II, which is based on the RTDpeak-trial.

  3. Evaluation of knee extensor mechanism disorders: clinical presentation of 1 12 patients*.

    Science.gov (United States)

    Antich, T J; Randall, C C; Westbrook, R A; Morrissey, M C; Brewster, C E

    1986-01-01

    Results of physical therapy evaluation of 112 patients with extensor mechanism disorders (chondromalacia patella, infrapatellar tendinitis, and peripatellar pain) are presented. An equal number of male and female patients were evaluated and of the 73 patients with unilateral involvement (65%) there were equal numbers of right and left involved knees. Running was the activity most commonly associated with pain, followed by basketball and tennis. Stairclimbing was painful in 79% of the patients, with ascending being more painful than descending in patients reporting a clear-cut difference. Hamstring and quadriceps tightness was statistically significant relative to the uninvolved limb although clinically, negligible differences were measured. The inferior pole of the patella was the most tender site to palpation, followed by medial peripatellar structures, then lateral sites. Biomechanical malalignment was not detected by the attending therapist in the majority of patients. The authors emphasize careful assessment of flexibility, quadriceps (VMOIVL) imbalance, and biomechanical alignment in performing a thorough evaluation of patients with extensor mechanism disorders. J Orthop Sports Phys Ther 1986;8(5):248-254.

  4. Isometric knee extensor fatigue following a Wingate test: peripheral and central mechanisms.

    Science.gov (United States)

    Fernandez-del-Olmo, M; Rodriguez, F A; Marquez, G; Iglesias, X; Marina, M; Benitez, A; Vallejo, L; Acero, R M

    2013-02-01

    Central and peripheral fatigue have been explored during and after running or cycling exercises. However, the fatigue mechanisms associated with a short maximal cycling exercise (30 s Wingate test) have not been investigated. In this study, 10 volunteer subjects performed several isometric voluntary contractions using the leg muscle extensors before and after two bouts of cycling at 25% of maximal power output and two bouts of Wingate tests. Transcranial magnetic stimulation (TMS) and electrical motor nerve stimulation (NM) were applied at rest and during the voluntary contractions. Maximal voluntary contraction (MVC), voluntary activation (VA), twitch amplitude evoked by electrical nerve stimulation, M wave and motor potential evoked by TMS (MEP) were recorded. MVC, VA and twitch amplitude evoked at rest by NM decreased significantly after the first and second Wingate tests, indicating central and peripheral fatigue. MVC and VA, but not the twitch amplitude evoked by NM, recovered before the second Wingate test. These results suggest that the Wingate test results in a decrease in MVC associated with peripheral and central fatigue. While the peripheral fatigue is associated with an intramuscular impairment, the central fatigue seems to be the main reason for the Wingate test-induced impairment of MVC.

  5. [Reflected high-intensity motion signals as markers of left ventricular diastolic dysfunction].

    Science.gov (United States)

    Makarenko, E S

    2013-01-01

    Reflected high-intensity signals of left ventricular motion can be used for assessment of diastolic function of left ventricle. There are many correlations between reflected high-intensity signals, transmitral flow, and tissue Doppler imaging parameters. Diagnostic criteria of LV diastolic dysfunction based on measurement of LV motion are suggested.

  6. High-intensity intermittent swimming improves cardiovascular health status for women with mild hypertension

    DEFF Research Database (Denmark)

    Mohr, Magni; Nordsborg, Nikolai Baastrup; Lindenskov, Annika

    2014-01-01

    To test the hypothesis that high-intensity swim training improves cardiovascular health status in sedentary premenopausal women with mild hypertension, sixty-two women were randomized into high-intensity (n = 21; HIT), moderate-intensity (n = 21; MOD), and control groups (n = 20; CON). HIT perfor...

  7. The influence of basketball dribbling on repeated high-intensity intermittent runs

    Directory of Open Access Journals (Sweden)

    Zhaowei Kong

    2015-12-01

    Conclusion: The results suggest that the Yo-Yo IE2 test could reflect the repeatability of high-intensity intermittent basketball dribbling performance, while dribbling skills may have different influences on high-intensity intermittent exercise capacity in adolescent players at different ages.

  8. Refinement of Eutectic Silicon Phase of Aluminum A356 Alloy Using High-Intensity Ultrasonic Vibration

    Energy Technology Data Exchange (ETDEWEB)

    Jian, Xiaogang [ORNL; Han, Qingyou [ORNL

    2006-01-01

    The eutectic silicon in A356 alloy can be refined and modified using either chemical, quench, or superheating modification. We observed, for the first time, that the eutectic silicon can also be significantly refined using high-intensity ultrasonic vibration. Rosette-like eutectic silicon is formed during solidification of specimen treated with high-intensity ultrasonic vibration.

  9. High Performance Human Face Recognition using Independent High Intensity Gabor Wavelet Responses: A Statistical Approach

    CERN Document Server

    Kar, Arindam; Basu, Dipak Kumar; Nasipuri, Mita; Kundu, Mahantapas

    2011-01-01

    In this paper, we present a technique by which high-intensity feature vectors extracted from the Gabor wavelet transformation of frontal face images, is combined together with Independent Component Analysis (ICA) for enhanced face recognition. Firstly, the high-intensity feature vectors are automatically extracted using the local characteristics of each individual face from the Gabor transformed images. Then ICA is applied on these locally extracted high-intensity feature vectors of the facial images to obtain the independent high intensity feature (IHIF) vectors. These IHIF forms the basis of the work. Finally, the image classification is done using these IHIF vectors, which are considered as representatives of the images. The importance behind implementing ICA along with the high-intensity features of Gabor wavelet transformation is twofold. On the one hand, selecting peaks of the Gabor transformed face images exhibit strong characteristics of spatial locality, scale, and orientation selectivity. Thus these...

  10. Short-term effects of implemented high intensity shoulder elevation during computer work

    Directory of Open Access Journals (Sweden)

    Madeleine Pascal

    2009-08-01

    Full Text Available Abstract Background Work-site strength training sessions are shown effective to prevent and reduce neck-shoulder pain in computer workers, but difficult to integrate in normal working routines. A solution for avoiding neck-shoulder pain during computer work may be to implement high intensity voluntary contractions during the computer work. However, it is unknown how this may influence productivity, rate of perceived exertion (RPE as well as activity and rest of neck-shoulder muscles during computer work. The aim of this study was to investigate short-term effects of a high intensity contraction on productivity, RPE and upper trapezius activity and rest during computer work and a subsequent pause from computer work. Methods 18 female computer workers performed 2 sessions of 15 min standardized computer mouse work preceded by 1 min pause with and without prior high intensity contraction of shoulder elevation. RPE was reported, productivity (drawings per min measured, and bipolar surface electromyography (EMG recorded from the dominant upper trapezius during pauses and sessions of computer work. Repeated measure ANOVA with Bonferroni corrected post-hoc tests was applied for the statistical analyses. Results The main findings were that a high intensity shoulder elevation did not modify RPE, productivity or EMG activity of the upper trapezius during the subsequent pause and computer work. However, the high intensity contraction reduced the relative rest time of the uppermost (clavicular trapezius part during the subsequent pause from computer work (p Conclusion Since a preceding high intensity shoulder elevation did not impose a negative impact on perceived effort, productivity or upper trapezius activity during computer work, implementation of high intensity contraction during computer work to prevent neck-shoulder pain may be possible without affecting the working routines. However, the unexpected reduction in clavicular trapezius rest during a

  11. The high intensity solar cell: Key to low cost photovoltaic power

    Science.gov (United States)

    Sater, B. L.; Goradia, C.

    1975-01-01

    The design considerations and performance characteristics of the 'high intensity' (HI) solar cell are presented. A high intensity solar system was analyzed to determine its cost effectiveness and to assess the benefits of further improving HI cell efficiency. It is shown that residential sized systems can be produced at less than $1000/kW peak electric power. Due to their superior high intensity performance characteristics compared to the conventional and VMJ cells, HI cells and light concentrators may be the key to low cost photovoltaic power.

  12. High-intensity focused ultrasound treatment of abnormal vaginal bleeding secondary to uterine myoma.

    Science.gov (United States)

    Lim, Jung Hyun; Chung, Dong Jin; Lim, Young Tec; Cho, Sae Hyun; Lee, Jae Mun; Hahn, Seong-Tae

    2011-03-01

    We describe the use of high-intensity focused ultrasound for acute vaginal bleeding secondary to uterine myoma in 2 young female patients. Both patients had episodes of abnormal vaginal bleeding with severe dysmenorrhea that was not efficiently controlled by medical treatment. After high-intensity focused ultrasound ablation, both vaginal bleeding control and symptom relief were achieved without postinterventional complications. The patients remained free of symptoms during 2 months of follow-up and regained normal menstruation after high-intensity focused ultrasound therapy. High-intensity focused ultrasound treatment is one of the least invasive options for dysfunctional vaginal bleeding and may be an effective and safe alternative to other procedures in women of reproductive age with abnormal vaginal bleeding secondary to uterine myoma.

  13. Extremely short duration high intensity interval training substantially improves insulin action in young healthy males

    DEFF Research Database (Denmark)

    Babraj, John A; Vollaard, Niels B J; Keast, Cameron

    2009-01-01

    BACKGROUND: Traditional high volume aerobic exercise training reduces cardiovascular and metabolic disease risk but involves a substantial time commitment. Extremely low volume high-intensity interval training (HIT) has recently been demonstrated to produce improvements to aerobic function, but i...

  14. Effect of preseason concurrent muscular strength and high-intensity interval training in professional soccer players.

    Science.gov (United States)

    Wong, Pui-lam; Chaouachi, Anis; Chamari, Karim; Dellal, Alexandre; Wisloff, Ulrik

    2010-03-01

    This study examined the effect of concurrent muscular strength and high-intensity running interval training on professional soccer players' explosive performances and aerobic endurance. Thirty-nine players participated in the study, where both the experimental group (EG, n = 20) and control group (CG, n = 19) participated in 8 weeks of regular soccer training, with the EG receiving additional muscular strength and high-intensity interval training twice per week throughout. Muscular strength training consisted of 4 sets of 6RM (repetition maximum) of high-pull, jump squat, bench press, back half squat, and chin-up exercises. The high-intensity interval training consisted of 16 intervals each of 15-second sprints at 120% of individual maximal aerobic speed interspersed with 15 seconds of rest. EG significantly increased (p aerobic speed test, and maximal aerobic speed. High-intensity interval running can be concurrently performed with high load muscular strength training to enhance soccer players' explosive performances and aerobic endurance.

  15. High-Intensity Intermittent Exercise: Effect on Young People's Cardiometabolic Health and Cognition.

    Science.gov (United States)

    Cooper, Simon B; Dring, Karah J; Nevill, Mary E

    2016-01-01

    With only a quarter of young people currently meeting physical activity guidelines, two key areas of concern are the effects of exercise on cardiometabolic health and cognition. Despite the fact that physical activity in young people is typically high intensity and intermittent in nature, much of the literature examines traditional endurance-type exercise. This review provides an update on the effects of high-intensity intermittent exercise on young people's cardiometabolic health and cognition. High-intensity intermittent exercise has acute beneficial effects on endothelial function and postprandial lipemia and chronic positive effects on weight management. In addition, there is emerging evidence regarding chronic benefits on the blood lipid profile, blood pressure, and proinflammatory and anti-inflammatory cytokines. Furthermore, emerging evidence suggests beneficial acute and chronic effects of high-intensity intermittent exercise on cognition. However, further research is required in both cardiometabolic health and cognition, particularly regarding the impact of school-based interventions in adolescents.

  16. High-intensity training reduces CD8+ T-cell redistribution in response to exercise

    NARCIS (Netherlands)

    Witard, O.C.; Turner, J.E.; Jackman, S.R.; Tipton, K.D.; Jeukendrup, A.E.; Kies, A.K.; Bosch, J.A.

    2012-01-01

    Purpose: We examined whether exercise-induced lymphocytosis and lymphocytopenia are impaired with high-intensity training. Methods: Eight trained cyclists (V·O2max = 64.2 ± 6.5 mL·kg-1·min-1) undertook 1 wk of normal-intensity training and a second week of high-intensity training. On day 7 of each w

  17. Design and implementation of capacitive micromachined ultrasonic transducers for high intensity focused ultrasound

    OpenAIRE

    Yamaner, Yalçın Feysel; Yamaner, Yalcin Feysel

    2011-01-01

    High intensity focused ultrasound (HIFU) is a medical procedure for noninvasive treatment of cancers. High intensity focused ultrasound is used to heat and destroy the diseased tissue. Piezoelectricity has been the core mechanism for generation of ultrasound waves in the treatment. Focusing can be done by using spherically curved transducers or using a lens or electronically steering sound waves by using phased arrays. Current research in HIFU technology targets the development of MR-guided m...

  18. Anthropometric, Sprint, and High-Intensity Running Profiles of English Academy Rugby Union Players by Position.

    Science.gov (United States)

    Darrall-Jones, Joshua D; Jones, Ben; Till, Kevin

    2016-05-01

    The purpose of this study was to evaluate the anthropometric, sprint, and high-intensity running profiles of English academy rugby union players by playing positions, and to investigate the relationships between anthropometric, sprint, and high-intensity running characteristics. Data were collected from 67 academy players after the off-season period and consisted of anthropometric (height, body mass, sum of 8 skinfolds [∑SF]), 40-m linear sprint (5-, 10-, 20-, and 40-m splits), the Yo-Yo intermittent recovery test level 1 (Yo-Yo IRTL-1), and the 30-15 intermittent fitness test (30-15 IFT). Forwards displayed greater stature, body mass, and ∑SF; sprint times and sprint momentum, with lower high-intensity running ability and sprint velocities than backs. Comparisons between age categories demonstrated body mass and sprint momentum to have the largest differences at consecutive age categories for forwards and backs; whereas 20-40-m sprint velocity was discriminate for forwards between under 16s, 18s, and 21s. Relationships between anthropometric, sprint velocity, momentum, and high-intensity running ability demonstrated body mass to negatively impact on sprint velocity (10 m; r = -0.34 to -0.46) and positively affect sprint momentum (e.g., 5 m; r = 0.85-0.93), with large to very large negative relationships with the Yo-Yo IRTL-1 (r = -0.65 to -0.74) and 30-15 IFT (r = -0.59 to -0.79). These findings suggest that there are distinct anthropometric, sprint, and high-intensity running ability differences between and within positions in junior rugby union players. The development of sprint and high-intensity running ability may be impacted by continued increases in body mass as there seems to be a trade-off between momentum, velocity, and the ability to complete high-intensity running.

  19. The effect of short-duration sub-maximal cycling on balance in single-limb stance in patients with anterior cruciate ligament injury: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Roberts David

    2004-11-01

    Full Text Available Abstract Background It has previously been shown that an anterior cruciate ligament (ACL injury may lead to impaired postural control, and that the ability to maintain postural control is decreased by fatigue in healthy subjects. To our knowledge, no studies have reported the effect of fatigue on postural control in subjects with ACL injury. This study was aimed at examining the effect of fatigue on balance in single-limb stance in subjects with ACL injury, and to compare the effects, and the ability to maintain balance, with that of a control group of uninjured subjects. Methods Thirty-six patients with unilateral, non-operated, non-acute ACL injury, and 24 uninjured subjects were examined with stabilometry before (pre-exercise and immediately after (post-exercise short-duration, sub-maximal cycling. In addition, the post-exercise measurements were compared, to evaluate the instantaneous ability to maintain balance and any possible recovery. The amplitude and average speed of center of pressure movements were registered in the frontal and sagittal planes. The paired t-test was used for the intra-group comparisons, and the independent t-test for the inter-group comparisons, with Bonferroni correction for multiple comparisons. Results No differences were found in the effects of exercise between the patients and the controls. Analysis of the post-exercise measurements revealed greater effects or a tendency towards greater effects on the injured leg than in the control group. The average speed was lower among the patients than in the control group. Conclusions The results of the present study showed no differences in the effects of exercise between the patients and the controls. However, the patients seemed to react differently regarding ability to maintain balance in single-limb stance directly after exercise than the control group. The lower average speed among the patients may be an expression of different neuromuscular adaptive strategies than

  20. EFFECT OF HIGH INTENSITY INTERVAL TRAINING ON ENDOTHELIAL FUNCTION IN POSTMENOPAUSAL HYPERTENSIVE PATIENTS RANDOMIZED CONTROLLED TRIAL

    Directory of Open Access Journals (Sweden)

    Mona Mohamed Taha

    2016-02-01

    Full Text Available Background: Postmenopausal hypertension is the most common risk factor of cardiovascular morbidity and mortality. As the exercises training conveys benefits of the setting of secondary prevention of hypertension. High intensity interval training (HIIT emerged as a new form of physical training and presents as therapeutic alternative to patients and health care professionals. This study aimed to investigate the effect of high intensity interval training on endothelial function in postmenopausal hypertension. Methods: Forty six mildly hypertensive postmenopausal women, their ages ranged from (45-55 years old, were randomly allocated to two groups: HIIT group (group-I; n=23 performed a high intensity interval training 3 times a week for 10 weeks at an intensity of (80-85% HR max for 40 minutes and control group (group-II; n=23 remains sedentary during this period. Serum nitric oxide (NO, vascular endothelial growth factor levels (VEGF and blood pressures were measured before and after intervention. Results: A significant reduction in both systolic and diastolic blood pressure values by 9.5% and 7 % respectively, was seen after high intensity interval training which was accompanied by increase in NO and VEGF levels by 43.3% and 15.2 % respectively, while no significant change observed in the control group. Conclusion: High intensity interval training had obvious benefits in improving plasma No, VEGF concentrations and controlling hypertension in postmenopausal women.

  1. Observation of fine particle aggregating behavior induced by high intensity conditioning using high speed CCD

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The aggregating behavior between bubbles and particles induced by high intensity conditioning (HIC) was studied using high speed CCD technique. Bubble size measurement was conducted, and the attachment behavior between bubbles and particles in HIC cell and flotation cell were observed. The results show that in HIC cell, high intensity conditioning creates an advantage environment for the formation of small size bubble due to hydrodynamic cavitations, and these fine bubbles have high probability of bubble-particle collision,which will enhance fine particle flotation. The bubble-particle attachment experiments indicate that in high intensity conditioning cell, a lot of fine bubbles are produced in situ on the surface of fine particles, and most of fine particles are aggregated under the bridging action of fine bubbles. The observation of bubble-particle interaction in flotation cell illustrates that aggregates created by HIC can be loaded more easily by big air bubble in flotation cell than those created by normal conditioning.

  2. Formation of Nanoscale Intermetallic Phases in Ni Surface Layer at High Intensity Implantation of Al Ions

    Institute of Scientific and Technical Information of China (English)

    I.A.Bozhko; S.V.Fortuna; I.A.Kurzina; I.B.Stepanov; E.V.Kozlov; Yu.P. Sharkeev

    2004-01-01

    The results of experimental study of nanoscale intermetallic formation in surface layer of a metal target at ion implantation are presented. To increase the thickness of the ion implanted surface layer the high intensive ion implantation is used. Compared with the ordinary ion implantation, the high intensive ion implantation allows a much thicker modified surface layer. Pure polycrystalline nickel was chosen as a target. Nickel samples were irradiated with Al ions on the vacuum-arc ion beam and plasma flow source "Raduga-5". It was shown that at the high intensity ion implantation the fine dispersed particles of Ni3Al, NiAl intermetallic compounds and solid solution Al in Ni are formed in the nickel surface layer of 200 nm and thicker. The formation of phases takes place in complete correspondence with the Ni-Al phase diagram.

  3. The high intensity solar cell - Key to low cost photovoltaic power

    Science.gov (United States)

    Sater, B. L.; Goradia, C.

    1975-01-01

    This paper discusses the problems associated with conventional solar cells at high intensities and presents the design considerations and performance characteristics of the 'high intensity' (HI) solar cell which appears to eliminate the major problems. Test data obtained at greater than 250 AM1 suns gave a peak output power density of 2 W per sq cm at an efficiency exceeding 6% with an unoptimized cell operating at over 100 C. It appears that operation at 1000 AM1 suns at efficiencies greater than 10% is possible. At 1000 AM1 suns and 10% efficiency, the HI cell manufacturing cost is estimated to be $0.25/watt, with multi-megawatt annual production capability already existing within the industrial sector. A high intensity solar system was also analyzed to determine its cost effectiveness and to assess the benefits of further improving HI cell efficiency.

  4. High-intensity intermittent swimming improves cardiovascular health status for women with mild hypertension

    DEFF Research Database (Denmark)

    Mohr, Magni; Nordsborg, Nikolai Baastrup; Lindenskov, Annika;

    2014-01-01

    To test the hypothesis that high-intensity swim training improves cardiovascular health status in sedentary premenopausal women with mild hypertension, sixty-two women were randomized into high-intensity (n = 21; HIT), moderate-intensity (n = 21; MOD), and control groups (n = 20; CON). HIT...... performed 6-10 × 30 s all-out swimming interspersed by 2 min recovery and MOD swam continuously for 1 h at moderate intensity for a 15-week period completing in total 44 ± 1 and 43 ± 1 sessions, respectively. In CON, all measured variables were similar before and after the intervention period. Systolic BP...... swim (13 ± 3% and 22 ± 3%), interval swimming (23 ± 3% and 8 ± 3%), and Yo-Yo IE1 running performance (58 ± 5% and 45 ± 4%). In conclusion, high-intensity intermittent swimming is an effective training strategy to improve cardiovascular health and physical performance...

  5. The clinical study on high intensity zone of magnetic resonance imaging using Scolopendrid Aquacupuncture.

    Directory of Open Access Journals (Sweden)

    Jeong-a Lim

    2006-12-01

    Full Text Available Objective : This study was designed to find out the effect of scolopendrid aquacupuncture on low back pain with or without sciatica showing high intensity zone of magnetic resonance imaging. Methods : The 30 patients who had a diagnosis of high intensity zone by lumbar-MRI and admitted to Gwangju oriental medical hospital in wonkwang university from January 2005 to August 2004 were observed. The symptom of inpatients is low back pain with or without sciatica. We treated 30 patients by scolopendrid aquacupuncture besides the general conservative treatment of oriental medicine. Results and Conclusion : The scolopendrid aquacupuncture treatment led to improvement in the pain and symptom of disability as determined by all efficacy measures. After scolopendrid aquacupuncture treatment, there was improvement in VAS, ROM and SLRT. This results suggest that scolopendrid aquacupuncture is good method for treatment of low back pain with or without sciatica showing high intensity zone of magnetic resonance imaging.

  6. Changes in satellite cells in human skeletal muscle after a single bout of high intensity exercise

    DEFF Research Database (Denmark)

    Crameri, Regina M; Langberg, Henning; Magnusson, Peter

    2004-01-01

    desmin or dystrophin, were not observed, and hence did not appear to induce the expression of either N-CAM or FA1. We therefore propose that satellite cells can be induced to re-enter the cell growth cycle after a single bout of unaccustomed high intensity exercise. However, a single bout of exercise......No studies to date have reported activation of satellite cells in vivo in human muscle after a single bout of high intensity exercise. In this investigation, eight individuals performed a single bout of high intensity exercise with one leg, the contralateral leg being the control. A significant...... increase in mononuclear cells staining for the neural cell adhesion molecule (N-CAM) and fetal antigen 1 (FA1) were observed within the exercised human vastus lateralis muscle on days 4 and 8 post exercise. In addition, a significant increase in the concentration of the FA1 protein was determined...

  7. Repeated high-intensity exercise modulates Ca(2+) sensitivity of human skeletal muscle fibers

    DEFF Research Database (Denmark)

    Gejl, K D; Hvid, L G; Willis, S J;

    2016-01-01

    The effects of short-term high-intensity exercise on single fiber contractile function in humans are unknown. Therefore, the purposes of this study were: (a) to access the acute effects of repeated high-intensity exercise on human single muscle fiber contractile function; and (b) to examine whether...... the fourth sprint with respect to Ca(2+) sensitivity and maximal Ca(2+) -activated force. To investigate the oxidative effects of exercise on single fiber contractile function, a subset of fibers was incubated with dithiothreitol (DTT) before analysis. Ca(2+) sensitivity was enhanced by exercise in both MHC...... I (17%, P exercise. In conclusion, repeated high-intensity exercise increased Ca(2+) sensitivity in both MHC I and MHC II...

  8. Enhancement of High-Intensity Focused Ultrasound Heating by Short-Pulse Generated Cavitation

    Directory of Open Access Journals (Sweden)

    Shin Yoshizawa

    2017-03-01

    Full Text Available A target tissue can be thermally coagulated in high-intensity focused ultrasound (HIFU treatment noninvasively. HIFU thermal treatments have been clinically applied to various solid tumors. One of the problems in HIFU treatments is a long treatment time. Acoustically driven microbubbles can accelerate the ultrasonic heating, resulting in the significant reduction of the treatment time. In this paper, a method named “trigger HIFU exposure” which employs cavitation microbubbles is introduced and its results are reviewed. A trigger HIFU sequence consists of high-intensity short pulses followed by moderate-intensity long bursts. Cavitation bubbles induced in a multiple focal regions by rapidly scanning the focus of high-intensity pulses enhanced the temperature increase significantly and produced a large coagulation region with high efficiency.

  9. High-intensity running in English FA Premier League soccer matches

    DEFF Research Database (Denmark)

    Bradley, Paul S.; Sheldon, William; Wooster, Blake

    2009-01-01

    The aims of this study were to (1) determine the activity profiles of a large sample of English FA Premier League soccer players and (2) examine high-intensity running during elite-standard soccer matches for players in various playing positions. Twenty-eight English FA Premier League games were.......01), attackers (2341 m, s=575, P game, high-intensity running distance was approximately 20% less than in the first 15-min period for wide midfielders (467 m, s=104 vs. 589 m, s=134, P ....01) and without ball possession (229 m, s=85 vs. 278 m, s=97, P game. Mean recovery time between very high-intensity running bouts was 72 s (s=28), with a 28% longer recovery time during the last 15 min than the first 15 min of the game (83 s, s=26 vs...

  10. Effect of high-intensity training on endothelial function in patients with cardiovascular and cerebrovascular disease

    DEFF Research Database (Denmark)

    Kolmos, Mia; Krawcyk, Rikke Steen; Kruuse, Christina

    2016-01-01

    OBJECTIVES: Exercise improves endothelial dysfunction, the key manifestation of cardiovascular and cerebrovascular disease, and is recommended in both cardiovascular and cerebrovascular rehabilitation. Disagreement remains, however, on the role of intensity of exercise. The purpose of this review...... was to gather current knowledge on the effects of high-intensity training versus moderate-intensity continuous exercise on endothelial function in cardiovascular and cerebrovascular patients. METHODS: A systematic review was performed in PubMed database, Embase and Cochrane libraries and on PEDro using...... the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were restricted to cardiovascular and cerebrovascular patients, and healthy subjects as general reference. Interventions comprised of high-intensity training alone, high-intensity training compared to moderate...

  11. Study in Parkinson Disease of Exercise (SPARX): Translating high-intensity exercise from animals to humans

    Science.gov (United States)

    Moore, Charity G.; Schenkman, Margaret; Kohrt, Wendy M.; Delitto, Anthony; Hall, Deborah A.; Corcos, Daniel

    2013-01-01

    A burgeoning literature suggests that exercise has a therapeutic benefit in persons with Parkinson disease (PD) and in animal models of PD, especially when animals exercise at high intensity. If exercise is to be prescribed as “first-line” or “add-on” therapy in patients with PD, we must demonstrate its efficacy and dose-response effects through testing phases similar to those used in the testing of pharmacologic agents. The SPARX Trial is a multicenter, randomized, controlled, single-blinded, Phase II study that we designed to test the feasibility of using high-intensity exercise to modify symptoms of PD and to simultaneously test the nonfutility of achieving a prespecified change in patients’ motor scores on the Unified Parkinson Disease Rating Scale (UPDRS). The trial began in May 2102 and is in the process of screening, enrolling, and randomly assigning 126 patients with early-stage PD to 1 of 3 groups: usual care (wait-listed controls), moderate-intensity exercise (4 days/week at 60%–65% maximal heart rate [HRmax]), or high-intensity exercise (4 days/week at 80%–85% HRmax). At 6-month follow-up, the trial is randomly reassigning usual care participants to a moderate-intensity or high-intensity exercise group for the remaining 6 months. The goals of the Phase II trial are to determine if participants can exercise at moderate and high intensities; to determine if either exercise yields benefits consistent with meaningful clinical change (nonfutility); and to document safety and attrition. The advantage of using a non-futility approach allows us to efficiently determine if moderate- or high-intensity exercise warrants further large-scale investigation in PD. PMID:23770108

  12. High-intensity erotic visual stimuli de-activate the primary visual cortex in women.

    Science.gov (United States)

    Huynh, Hieu K; Beers, Caroline; Willemsen, Antoon; Lont, Erna; Laan, Ellen; Dierckx, Rudi; Jansen, Monique; Sand, Michael; Weijmar Schultz, Willibrord; Holstege, Gert

    2012-06-01

    The primary visual cortex, Brodmann's area (BA 17), plays a vital role in basic survival mechanisms in humans. In most neuro-imaging studies in which the volunteers have to watch pictures or movies, the primary visual cortex is similarly activated independent of the content of the pictures or movies. However, in case the volunteers perform demanding non-visual tasks, the primary visual cortex becomes de-activated, although the amount of incoming visual sensory information is the same. Do low- and high-intensity erotic movies, compared to neutral movies, produce similar de-activation of the primary visual cortex? Brain activation/de-activation was studied by Positron Emission Tomography scanning of the brains of 12 healthy heterosexual premenopausal women, aged 18-47, who watched neutral, low- and high-intensity erotic film segments. We measured differences in regional cerebral blood flow (rCBF) in the primary visual cortex during watching neutral, low-intensity erotic, and high-intensity erotic film segments. Watching high-intensity erotic, but not low-intensity erotic movies, compared to neutral movies resulted in strong de-activation of the primary (BA 17) and adjoining parts of the secondary visual cortex. The strong de-activation during watching high-intensity erotic film might represent compensation for the increased blood supply in the brain regions involved in sexual arousal, also because high-intensity erotic movies do not require precise scanning of the visual field, because the impact is clear to the observer. © 2012 International Society for Sexual Medicine.

  13. Influence of mature men way of life on highly intensive physical activity

    Directory of Open Access Journals (Sweden)

    O.B. Pryshva

    2017-04-01

    Full Text Available Highly intensive physical activity is the most effective for men’s health protection. In modern life conditions its level is insufficient. It requires organism’s appropriate physical activity, which is determined by way of life. Especially important it is before trainings. Purpose: to study special aspects of different intensity’s physical activity; of eating special food and sleeping regime of mature men before their highly intensive physical trainings. Material: in experiment men (n=26, age - 35-53years, who practice healthy life style and independent physical activity of high intensity, participated. We used bio-register Basis B1. Every day we registered: Peak - physical activity of different intensity; duration and quality of sleep; relative weight of consumed food. Besides, we calculated body mass index and physical condition. The study was conducted during 30 days in winter period. The following results were compared: indicators before not planned physical activity and average-monthly indicators. Results: Before arbitrary physical functioning we found in men: confident weakening of average intensity (by 9-11% and low intensity (by 10% physical activity; confident increase of consumed food’s relative weight (by 6.82%, vegetarian food (by 10.64% and raw food (by 7.61%; confident reduction of animal origin food (by 8.7%. No changes were found in duration and quality of sleep before highly intensive physical functioning. Conclusions: specific features of mature men’s way of life before their not planned highly intensive physical functioning are as follows: reduction of general physical activity; increase of consumed food. These factors facilitate energy accumulation in organism for its realization in highly intensive physical functioning the next day.

  14. Moderate-to-high intensity aerobic exercise in patients with mild to moderate Alzheimer's disease

    DEFF Research Database (Denmark)

    Frederiksen, Kristian S; Sobol, Nanna; Beyer, Nina

    2014-01-01

    OBJECTIVES: Physical exercise may modulate neuropathology and symptoms of Alzheimer's disease (AD). This pilot study assessed the feasibility of conducting a study of moderate-to-high intensity aerobic exercise in home-dwelling patients with mild AD. METHODS: An uncontrolled preintervention...

  15. Dynamics of cavitation clouds within a high-intensity focused ultrasonic beam

    NARCIS (Netherlands)

    Lu, Yuan; Katz, Joseph; Prosperetti, Andrea

    2013-01-01

    In this experimental study, we generate a 500 kHz high-intensity focused ultrasonic beam, with pressure amplitude in the focal zone of up to 1.9 MPa, in initially quiescent water. The resulting pressure field and behavior of the cavitation bubbles are measured using high-speed digital in-line hologr

  16. High Intensity Pressure Noise Transmission in Human Ear: A Three Dimensional Simulation Study

    Science.gov (United States)

    Hawa, Takumi; Gan, Rong; Leckness, Kegan

    2015-03-01

    High intensity pressure noise generated by explosions and jet engines causes auditory damage and hearing loss of the military service personals, which are the most common disabilities in the veterans. Authors have investigated the high intensity pressure noise transmission from the ear canal to middle ear cavity. A fluid-structure interaction with a viscoelastic model for the tympanic membrane (TM) as well as the ossicular chain has been considered in the study. For the high intensity pressure simulation the geometry of the ear was based on a 3D finite element (FE) model of the human ear reported by Gan et al. (Ann Biomed Eng 2004). The model consists of the ear canal, TM, ossicular chain, and the middle ear cavity. The numerical approach includes two steps: 1) FE based finite-volume method simulation to compute pressure distributions in the ear canal and the middle ear cavity using CFX; and 2) FE modeling of TM and middle ear ossicles in response to high intensity sound using multi-physics analysis in ANSYS. The simulations provide the displacement of the TM/ossicular chain and the pressure fields in the ear canal and the middle ear cavity. These results are compared with human temporal bone experimental data obtained in our group. This work was supported by DOD W81XWH-14-1-0228.

  17. Edward Teller medal lecture: high intensity lasers and the road to ignition

    Energy Technology Data Exchange (ETDEWEB)

    Key, M.H.

    1997-06-02

    There has been much progress in the development of high intensity lasers and in the science of laser driven inertially confined fusion such that ignition is now a near term prospect. This lecture reviews the field with particular emphasis on areas of my own involvement.

  18. [Metabolic response to high intensity exercise training in sedentary hyperglycemic and hypercholesterolemic women].

    Science.gov (United States)

    Alvarez L, Cristian; Ramírez-Campillo, Rodrigo; Flores O, Marcelo; Henríquez-Olguín, Carlos; Campos J, Christian; Carrasco, Vanesa; Martínez S, Cristian; Celis-Morales, Carlos

    2013-10-01

    High intensity training could be an effective way of improving health on individuals at high metabolic risk. To investigate the effects of a high intensity training intervention on metabolic-related markers in sedentary women at high metabolic risk. Forty six sedentary women with a body mass index (BMI) over 25 kg/m² were assigned to four groups, according to their metabolic profile; hyperglycemia (H, n = 12), hyperglycemia/hypercholesterolemia (HH, n = 13), normoglycemia (N, n = 10) and normoglycemia/hypercholesterolemia (NH, n = 11). For 12 weeks and five days per week, subjects performed seven intervals of high intensity training (20 to 30 seconds) during a training session of 20 minutes. Anthropometric (body weight, body mass index (BMI), waist circumference) and metabolic variables (glucose, total cholesterol, LDL, HDL and TG) were measured at baseline, at 6 and 12 weeks of intervention. BMI and waist circumference decreased significantly after 12 weeks of intervention. Similarly, glucose decreased significantly after 12 weeks of intervention in all groups. The reduction was of higher magnitude in those groups with hyperglycemia (H = -16%, HH = -22%, N = -7,5%, NH = -9,6%). However, lipid profile (TG, total cholesterol, LDL and HDL) improved significantly only in the hypercholesterolemic groups. Physical activity programs incorporating high intensity training can improve glucose and lipid profile in women with metabolic disorders. Moreover, this benefit is greatest in those individuals with highest metabolic burden.

  19. High-intensity interval training evokes larger serum BDNF levels compared with intense continuous exercise.

    Science.gov (United States)

    Saucedo Marquez, Cinthia Maria; Vanaudenaerde, Bart; Troosters, Thierry; Wenderoth, Nicole

    2015-12-15

    Exercise can have a positive effect on the brain by activating brain-derived neurotrophic factor (BDNF)-related processes. In healthy humans there appears to be a linear relationship between exercise intensity and the positive short-term effect of acute exercise on BDNF levels (i.e., the highest BDNF levels are reported after high-intensity exercise protocols). Here we performed two experiments to test the effectiveness of two high-intensity exercise protocols, both known to improve cardiovascular health, to determine whether they have a similar efficacy in affecting BDNF levels. Participants performed a continuous exercise (CON) protocol at 70% of maximal work rate and a high-intensity interval-training (HIT) protocol at 90% of maximal work rate for periods of 1 min alternating with 1 min of rest (both protocols lasted 20 min). We observed similar BDNF kinetics in both protocols, with maximal BDNF concentrations being reached toward the end of training (experiment 1). We then showed that both exercise protocols significantly increase BDNF levels compared with a rest condition (CON P = 0.04; HIT P exercise are slightly more effective than continuous high-intensity exercise for elevating serum BDNF. Additionally, 73% of the participants preferred the HIT protocol (P = 0.02). Therefore, we suggest that the HIT protocol might represent an effective and preferred intervention for elevating BDNF levels and potentially promoting brain health.

  20. High intensity polarization entangled source with a 2D nonlinear photonic crystal

    DEFF Research Database (Denmark)

    Wang, Qin

    2009-01-01

    We gave a proposal on how to use a piece of two-dimension (2D) nonlinear photonic crystal to generate a polarization entangled source. It provides not only has a high stability, but also a high entangled quality and a high intensity. Moreover, our scheme involves only practical experimental...

  1. High-intensity interval training and athletic performance in Taekwondo athletes.

    Science.gov (United States)

    Monks, Lynne; Seo, Myong-Won; Kim, Hyun-Bae; Jung, Hyun C; Song, Jong K

    2017-10-01

    The purpose of this study was to determine the effects of high-intensity interval training (HIIT) on athletic performance in Taekwondo athletes. Thirty-three male and female collegiate Taekwondo athletes were randomly divided into a HIIT group (N.=16) or a high-intensity continuous running (HICR) group (N.=17). The HIIT group undertook training of high-intensity sprints interspersed with active rest periods whilst the HICR group participated in high-intensity running for a continuous period. Both groups completed 11 sessions over 4 weeks. Physique, body composition, Wingate anaerobic test and VO2max test were measured. The vertical jump test, agility T-test and sit-ups were used to assess physical fitness. Repeated measures ANCOVAs with sex as a covariate were applied and significant level was set at 0.05. Following 11 sessions of training, significant improvements in anaerobic peak power (PTaekwondo competition performance in collegiate Taekwondo athletes. This could inform the future planning of Taekwondo athletes' pre-competition training, specifically the influence of training intensity on anaerobic capacity.

  2. Windowless microfluidic platform based on capillary burst valves for high intensity x-ray measurements

    DEFF Research Database (Denmark)

    Vig, Asger Laurberg; Haldrup, Kristoffer; Enevoldsen, Nikolaj Brandt;

    2009-01-01

    We propose and describe a microfluidic system for high intensity x-ray measurements. The required open access to a microfluidic channel is provided by an out-of-plane capillary burst valve (CBV). The functionality of the out-of-plane CBV is characterized with respect to the diameter of the window...

  3. Selected List of Low Energy Beam Transport Facilities for Light-Ion, High-Intensity Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Prost, L. R. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)

    2016-02-17

    This paper presents a list of Low Energy Beam Transport (LEBT) facilities for light-ion, high-intensity accelerators. It was put together to facilitate comparisons with the PXIE LEBT design choices. A short discussion regarding the importance of the beam perveance in the choice of the transport scheme follows.

  4. Triggered Drug Release from Superhydrophobic Meshes using High-Intensity Focused Ultrasound

    OpenAIRE

    Yohe, Stefan T.; Kopechek, Jonathan A.; Porter, Tyrone M; Colson, Yolonda L.; Grinstaff, Mark W.

    2013-01-01

    Application of high-intensity focused ultrasound to drug-loaded superhydrophobic meshes affords triggered drug release by displacing an entrapped air layer. The air layer within the superhydrophobic meshes is characterized using direct visualization and B-mode imaging. Drug-loaded superhydrophobic meshes are cytotoxic in an in vitro assay after ultrasound treatment.

  5. Towards MR-guided high intensity focused ultrasound ablation of liver tumors

    NARCIS (Netherlands)

    Wijlemans, J.W.

    2015-01-01

    Magnetic Resonance-guided High Intensity Focused Ultrasound (MR-HIFU) is a promising technique which can be used for completely non-invasive tissue ablation. The converging ultrasound beam penetrates the skin and subcutaneous tissues with damage, while heating the tissue only in the focal point. The

  6. MRI-guided High-Intensity Focused Ultrasound of Breast Cancer

    NARCIS (Netherlands)

    Merckel, L.G.

    2014-01-01

    Magnetic resonance imaging-guided high-intensity focused ultrasound (MR-HIFU) is a promising technique for completely noninvasive tumor ablation. This thesis focuses on its application for the treatment of patients with breast cancer. The first part of the thesis describes the role of breast MRI for

  7. Work in progress at the North Area High Intensity Facility (NAHIF)

    CERN Document Server

    1979-01-01

    The photo shows the exit of the two MBN-type magnets in tunnel TDC85 (upstream of TCC8), used to 'switch' the primary proton beam either towards target T8 (to the left) or onto target T10 (straight) to produce the H10 or the F12 (high-intensity electron/gamma) beam, respectively.

  8. 21 CFR 1040.30 - High-intensity mercury vapor discharge lamps.

    Science.gov (United States)

    2010-04-01

    ... mercury and that is contained within an outer envelope. (2) Advertisement means any catalog, specification... ballast is an inductive reactor designed to have the operating characteristics as listed in Section 7 in... advertisement. Advertising for any high-intensity mercury vapor discharge lamp that does not comply...

  9. Bone metastasis treatment using magnetic resonance-guided high intensity focused ultrasound

    NARCIS (Netherlands)

    Yeo, Sin Yuin; Elevelt, Aaldert; Donato, Katia; van Rietbergen, Bert; ter Hoeve, Natalie D.; van Diest, Paul J.; Grüll, Holger

    2015-01-01

    Objectives: Bone pain resulting from cancer metastases reduces a patient's quality of life. Magnetic Resonance-guided High Intensity Focused Ultrasound (MR-HIFU) is a promising alternative palliative thermal treatment technique for bone metastases that has been tested in a few clinical studies. Here

  10. Productions of hollow atoms from solids irradiated by high intensity laser

    Energy Technology Data Exchange (ETDEWEB)

    Moribayashi, K.; Sasaki, A.; Zhidkov, A. [Advanced Photon Research Center, Kansai Research Establishment, Japan Atomic Energy Research Inst. (Japan)

    2001-07-01

    The production of hollow atoms through the collisions of fast electrons with a solid is studied. These electrons are produced by high-intensity short-pulse laser irradiation on a solid. The inner-shell ionization and excitation processes by the fast electron impact are investigated. It is found that ionization processes give more significant contribution to the production of hollow atoms. (orig.)

  11. Status of High Intensity Polarized Electron Gun at Mit-Bates

    Science.gov (United States)

    Tsentalovich, E.; Bessuille, J.; Tiunov, M.

    2011-01-01

    MIT-Bates, in collaboration with BNL, has developed a high intensity polarized electron gun for the eRHIC project. The gun implements large area cathode, ring-shaped beam and active cathode cooling. The paper describes the current status of the project.

  12. The Edward Teller Medal Lecture: High Intensity Lasers and the Road to Ignition (lirpp Vol. 13)

    Science.gov (United States)

    Key, M. H.

    2016-10-01

    There has been much progress in the development of high intensity lasers and in the science of laser driven inertially confined fusion such that ignition is now a near term prospect. This lecture reviews the field with particular emphasis on areas of my own involvement.

  13. MRI-guided High-Intensity Focused Ultrasound of Breast Cancer

    NARCIS (Netherlands)

    Merckel, L.G.

    2014-01-01

    Magnetic resonance imaging-guided high-intensity focused ultrasound (MR-HIFU) is a promising technique for completely noninvasive tumor ablation. This thesis focuses on its application for the treatment of patients with breast cancer. The first part of the thesis describes the role of breast MRI for

  14. Postexercise cold-water immersion improves intermittent high-intensity exercise performance in normothermia.

    Science.gov (United States)

    McCarthy, Avina; Mulligan, James; Egaña, Mikel

    2016-11-01

    A brief cold water immersion between 2 continuous high-intensity exercise bouts improves the performance of the latter compared with passive recovery in the heat. We investigated if this effect is apparent in normothermic conditions (∼19 °C), employing an intermittent high-intensity exercise designed to reflect the work performed at the high-intensity domain in team sports. Fifteen young active men completed 2 exhaustive cycling protocols (Ex1 and Ex2: 12 min at 85% ventilatory threshold (VT) and then an intermittent exercise alternating 30-s at 40% peak power (Ppeak) and 30 s at 90% Ppeak to exhaustion) separated by 15 min of (i) passive rest, (ii) 5-min cold-water immersion at 8 °C, and (iii) 10-min cold-water immersion at 8 °C. Core temperature, heart rate, rates of perceived exertion, and oxygen uptake kinetics were not different during Ex1 among conditions. Time to failure during the intermittent exercise was significantly (P intermittent high-intensity exercise compared with passive rest in normothermia due, at least in part, to reductions in core temperature, circulatory strain, and effort perception.

  15. Effects of 12 weeks high-intensity & reduced-volume training in elite athletes

    DEFF Research Database (Denmark)

    Kilen, Anders; Larsson, Tanja Hultengren; Jørgensen, Majke;

    2014-01-01

    It was investigated if high-intensity interval training (HIT) at the expense of total training volume improves performance, maximal oxygen uptake and swimming economy. 41 elite swimmers were randomly allocated to a control (CON) or HIT group. For 12 weeks both groups trained ∼12 h per week. HIT c...

  16. Responses of Plasma Atrial Natriuretic Peptide to High Intensity Submaximal Exercise in the Heat,

    Science.gov (United States)

    1987-06-01

    Natriuretic Peptide to LnHigh Intensity Submaximal Exercise in the Heat 0 " William J. Kraemer. Lawrence E. Armstrong, Roger W. Hubbard. :I[_] Louis J...atriopeptins in rat adrenal cells. Cir Res 57: 113-118. f V-0C -- V- - IF -I 7 - % 7 -. 17 Chartier L. Schiffrin EL. Thibault G (1984). Effects of atrial

  17. Acute Effect of High-Intensity Eccentric Exercise on Vascular Endothelial Function in Young Men.

    Science.gov (United States)

    Choi, Youngju; Akazawa, Nobuhiko; Zempo-Miyaki, Asako; Ra, Song-Gyu; Shiraki, Hitoshi; Ajisaka, Ryuichi; Maeda, Seiji

    2016-08-01

    Choi, Y, Akazawa, N, Zempo-Miyaki, A, Ra, S-G, Shiraki, H, Ajisaka, R, and Maeda, S. Acute effect of high-intensity eccentric exercise on vascular endothelial function in young men. J Strength Cond Res 30(8): 2279-2285, 2016-Increased central arterial stiffness is as an independent risk factor for cardiovascular disease. Evidence regarding the effects of high-intensity resistance exercise on vascular endothelial function and central arterial stiffness is conflicting. The purpose of this study was to examine the effects of acute high-intensity eccentric exercise on vascular endothelial function and central arterial stiffness. We evaluated the acute changes in endothelium-dependent flow-mediated dilation (FMD), low-flow-mediated constriction (L-FMC), and arterial stiffness after high-intensity eccentric exercise. Seven healthy, sedentary men (age, 24 ± 1 year) performed maximal eccentric elbow flexor exercise using their nondominant arm. Before and 45 minutes after eccentric exercise, carotid arterial compliance and brachial artery FMD and L-FMC in the nonexercised arm were measured. Carotid arterial compliance was significantly decreased, and β-stiffness index significantly increased after eccentric exercise. Brachial FMD was significantly reduced after eccentric exercise, whereas there was no significant difference in brachial L-FMC before and after eccentric exercise. A positive correlation was detected between change in arterial compliance and change in FMD (r = 0.779; p ≤ 0.05), and a negative correlation was detected between change in β-stiffness index and change in FMD (r = -0.891; p eccentric exercise. In this study, acute high-intensity eccentric exercise increased central arterial stiffness; this increase was accompanied by a decrease in endothelial function caused by reduced endothelium-dependent vasodilation but not by a change in endothelium-dependent vasoconstriction.

  18. High-intensity exercise attenuates postprandial lipaemia and markers of oxidative stress.

    Science.gov (United States)

    Gabriel, Brendan; Ratkevicius, Aivaras; Gray, Patrick; Frenneaux, Michael P; Gray, Stuart R

    2012-09-01

    Regular exercise can reduce the risk of CVD (cardiovascular disease). Although moderate-intensity exercise can attenuate postprandial TAG (triacylglycerol), high-intensity intermittent exercise might be a more effective method to improve health. We compared the effects of high-intensity intermittent exercise and 30 min of brisk walking on postprandial TAG, soluble adhesion molecules and markers of oxidative stress. Nine men each completed three 2-day trials. On day 1, subjects rested (control), walked briskly for 30 min (walking) or performed 5×30 s maximal sprints (high-intensity). On day 2, subjects consumed a high-fat meal for breakfast and 3 h later for lunch. Blood samples were taken at various times and analysed for TAG, glucose, insulin, ICAM-1 (intracellular adhesion molecule-1), VCAM-1 (vascular adhesion molecule-1), TBARS (thiobarbituric acid- reactive substances), protein carbonyls and β-hydroxybutyrate. On day 2 of the high-intensity trial, there was a lower (Phigh-intensity trial (14.13±2.83 mmol/l per 7 h) compared with control (17.18±3.92 mmol/l per 7 h), walking showed no difference (16.33±3.51 mmol/l per 7 h). On day 2 of the high-intensity trial plasma TBARS and protein carbonyls were also reduced (Phigh-intensity intermittent exercise attenuates postprandial TAG and markers of oxidative stress after the consumption of a high-fat meal.

  19. Is high-intensity exercise better than moderate-intensity exercise for weight loss?

    Science.gov (United States)

    De Feo, P

    2013-11-01

    This viewpoint debates the state-of-the-art research focusing on the optimal intensity of the exercise programs for inducing a sustained weight or fat-mass loss in overweight/obese people. In our demanding society, the most attractive messages in the popular press are those promising the best results in a short time. This might explain the emphasis given by media to those scientific articles that report the efficacy on weight loss of exercise programs by their shorter duration and higher intensity. However, in the literature on overweight or obese people, there is little conclusive evidence for more favorable effects with high-intensity training than with continuous moderate-intensity exercise on body weight or fat mass loss. Since both exercise protocols have been demonstrated as useful to reduce body weight, the decision on the intensity of exercise prescription should be individualized and based on outcomes different from fat or weight loss. In this regard, there are pro and contra arguments for the prescription of high-intensity aerobic exercise in obese people. Among the pro arguments, is the demonstration that, in several studies, high-intensity training appears to induce superior improvements in aerobic fitness. Among the contra arguments to prescribe high-intensity exercise is the demonstration that prescribing a higher-intensity exercise decreases adherence and results in the completion of less exercise. Thus, a successful exercise program should be proposed at a moderate intensity and a low perceived effort because obese subjects who have low self-efficacy, poor mood status, and are not familiar with high-intensity workouts could easily drop out. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Psychophysiological effects of music on acute recovery from high-intensity interval training.

    Science.gov (United States)

    Jones, Leighton; Tiller, Nicholas B; Karageorghis, Costas I

    2017-03-01

    Numerous studies have examined the multifarious effects of music applied during exercise but few have assessed the efficacy of music as an aid to recovery. Music might facilitate physiological recovery via the entrainment of respiratory rhythms with music tempo. High-intensity exercise training is not typically associated with positive affective responses, and thus ways of assuaging negative affect warrant further exploration. This study assessed the psychophysiological effects of music on acute recovery and prevalence of entrainment in between bouts of high-intensity exercise. Thirteen male runners (Mage=20.2±1.9years; BMI=21.7±1.7; V̇O2 max=61.6±6.1mL·kg·min(-1)) completed three exercise sessions comprising 5×5-min bouts of high-intensity intervals interspersed with 3-min periods of passive recovery. During recovery, participants were administered positively-valenced music of a slow-tempo (55-65bpm), fast-tempo (125-135bpm), or a no-music control. A range of measures including affective responses, RPE, cardiorespiratory indices (gas exchange and pulmonary ventilation), and music tempo-respiratory entrainment were recorded during exercise and recovery. Fast-tempo, positively-valenced music resulted in higher Feeling Scale scores throughout recovery periods (p<0.01, ηp(2)=0.38). There were significant differences in HR during initial recovery periods (p<0.05, ηp(2)=0.16), but no other music-moderated differences in cardiorespiratory responses. In conclusion, fast-tempo, positively-valenced music applied during recovery periods engenders a more pleasant experience. However, there is limited evidence that music expedites cardiorespiratory recovery in between bouts of high-intensity exercise. These findings have implications for athletic training strategies and individuals seeking to make high-intensity exercise sessions more pleasant.

  1. Transverse Beam Halo Measurements at High Intensity Neutrino Source (HINS) using Vibrating Wire Monitor

    Energy Technology Data Exchange (ETDEWEB)

    Chung, M.; Hanna, B.; Scarpine, V.; Shiltsev, V.; Steimel, J.; Artinian, S.; Arutunian, S.

    2015-02-26

    The measurement and control of beam halos will be critical for the applications of future high-intensity hadron linacs. In particular, beam profile monitors require a very high dynamic range when used for the transverse beam halo measurements. In this study, the Vibrating Wire Monitor (VWM) with aperture 60 mm was installed at the High Intensity Neutrino Source (HINS) front-end to measure the transverse beam halo. A vibrating wire is excited at its resonance frequency with the help of a magnetic feedback loop, and the vibrating and sensitive wires are connected through a balanced arm. The sensitive wire is moved into the beam halo region by a stepper motor controlled translational stage. We study the feasibility of the vibrating wire for the transverse beam halo measurements in the low-energy front-end of the proton linac.

  2. Beam Dynamics Observations of the 2015 High Intensity Scrubbing Runs at the Cern Sps

    CERN Document Server

    Bartosik, Hannes; Li, Kevin; Mether, Lotta; Romano, Annalisa; Rumolo, Giovanni; Schenk, Michael

    2016-01-01

    Beam quality degradation caused by e-cloud effects has been identified as one of the main performance limitations for high intensity LHC beams with 25 ns bunch spacing in the SPS. In view of the beam parameters targeted with the LHC injectors upgrade (LIU) project, about two weeks of SPS machine time in 2015 were devoted to dedicated scrubbing runs with high intensity LHC 25 ns and dedicated 'doublet' beams in order to study the achievable reduction of e-cloud effects and quantify the consequent beam performance improvements. This paper describes the main observations concerning the coherent instabilities and beam dynamics limitations encountered as well as a detailed characterisation of the performance reach with the highest beam intensity presently available from the pre-injectors.

  3. Effect of moderate- and high-intensity acute exercise on appetite in obese individuals

    DEFF Research Database (Denmark)

    Martins, Catia; Stensvold, Dorthe; Finlayson, Graham

    2015-01-01

    cycling (MICC) or short-duration HIIC (S-HIIC) (125 kcal) and a resting control condition on the appetite hormone responses, subjective feelings of appetite, energy intake (EI), and food reward in overweight/obese individuals. METHODS: This study is a randomized crossover study on 12 overweight/obese......, hunger or fullness ratings, EI, or food reward. CONCLUSIONS: Our findings suggest that, in overweight/obese individuals, isocaloric bouts of moderate- or high-intensity exercise lead to a similar appetite response. This strengthens previous findings in normal-weight individuals that acute exercise, even......PURPOSE: The effect of acute exercise, and exercise intensity, on appetite control in obese individuals requires further study. The aim of this study was to compare the effects of acute isocaloric bouts (250 kcal) of high-intensity intermittent cycling (HIIC) and moderate-intensity continuous...

  4. Beam Dynamics Studies for High-Intensity Beams in the CERN Proton Synchrotron

    CERN Document Server

    AUTHOR|(CDS)2082016; Benedikt, Michael

    With the discovery of the Higgs boson, the existence of the last missing piece of the Standard Model of particle physics (SM) was confirmed. However, even though very elegant, this theory is unable to explain, for example, the generation of neutrino masses, nor does it account for dark energy or dark matter. To shed light on some of these open questions, research in fundamental particle physics pursues two complimentary approaches. On the one hand, particle colliders working at the high-energy frontier, such as the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN), located in Geneva, Switzerland, are utilized to investigate the fundamental laws of nature. Alternatively, fixed target facilities require high-intensity beams to create a large flux of secondary particles to investigate, for example, rare particle decay processes, or to create neutrino beams. This thesis investigates limitations arising during the acceleration of high-intensity beams at the CERN Proton Synchrotro...

  5. Short-term effects of implemented high intensity shoulder elevation during computer work

    DEFF Research Database (Denmark)

    Larsen, Mette K.; Samani, Afshin; Madeleine, Pascal

    2009-01-01

    elevation. RPE was reported, productivity (drawings per min) measured, and bipolar surface electromyography (EMG) recorded from the dominant upper trapezius during pauses and sessions of computer work. Repeated measure ANOVA with Bonferroni corrected post-hoc tests was applied for the statistical analyses......BACKGROUND: Work-site strength training sessions are shown effective to prevent and reduce neck-shoulder pain in computer workers, but difficult to integrate in normal working routines. A solution for avoiding neck-shoulder pain during computer work may be to implement high intensity voluntary...... contractions during the computer work. However, it is unknown how this may influence productivity, rate of perceived exertion (RPE) as well as activity and rest of neck-shoulder muscles during computer work. The aim of this study was to investigate short-term effects of a high intensity contraction...

  6. High Intensity Laser Power Beaming Architecture for Space and Terrestrial Missions

    Science.gov (United States)

    Nayfeh, Taysir; Fast, Brian; Raible, Daniel; Dinca, Dragos; Tollis, Nick; Jalics, Andrew

    2011-01-01

    High Intensity Laser Power Beaming (HILPB) has been developed as a technique to achieve Wireless Power Transmission (WPT) for both space and terrestrial applications. In this paper, the system architecture and hardware results for a terrestrial application of HILPB are presented. These results demonstrate continuous conversion of high intensity optical energy at near-IR wavelengths directly to electrical energy at output power levels as high as 6.24 W from the single cell 0.8 cm2 aperture receiver. These results are scalable, and may be realized by implementing receiver arraying and utilizing higher power source lasers. This type of system would enable long range optical refueling of electric platforms, such as MUAV s, airships, robotic exploration missions and provide power to spacecraft platforms which may utilize it to drive electric means of propulsion.

  7. A New Scheme for High-Intensity Laser-Driven Electron Acceleration in a Plasma 2

    CERN Document Server

    Sadykova, S P; Samkharadze, T G

    2015-01-01

    We propose a new approach to high-intensity relativistic laser-driven electron acceleration in a plasma. Here, we demonstrate that a plasma wave generated by a stimulated forward-scattering of an incident laser pulse can be in the longest acceleration phase with injected relativistic beam electrons. This is why the plasma wave has the maximum amplification coefficient which is determined by the acceleration time and the breakdown (overturn) electric field in which the acceleration of the injected beam electrons occurs. We must note that for the longest acceleration phase the relativity of the injected beam electrons plays a crucial role in our scheme. We estimate qualitatively the acceleration parameters of relativistic electrons in the field of a plasma wave generated at the stimulated forward-scattering of a high-intensity laser pulse in a plasma.

  8. High performance computation on beam dynamics problems in high intensity compact cyclotrons

    Institute of Scientific and Technical Information of China (English)

    ADELMANN; Andreas

    2011-01-01

    This paper presents the research progress in the beam dynamics problems for future high intensity compact cyclotrons by utilizing the state-of-the-art high performance computation technology. A "Start-to-Stop" model, which includes both the interaction of the internal particles of a single bunch and the mutual interaction of neighboring multiple bunches in the radial direction, is established for compact cyclotrons with multi-turn extraction. This model is then implemented in OPAL-CYCL, which is a 3D object-oriented parallel code for large scale particle simulations in cyclotrons. In addition, to meet the running requirement of parallel computation, we have constructed a small scale HPC cluster system and tested its performance. Finally, the high intensity beam dynamics problems in the 100 MeV compact cyclotron, which is being constructed at CIAE, are studied using this code and some conclusions are drawn.

  9. Effects of High-Intensity Blood Flow Restriction Exercise on Muscle Fatigue

    Directory of Open Access Journals (Sweden)

    Neto Gabriel R.

    2014-07-01

    Full Text Available Strength training combined with blood flow restriction (BFR have been used to improve the levels of muscle adaptation. The aim of this paper was to investigate the acute effect of high intensity squats with and without blood flow restriction on muscular fatigue levels. Twelve athletes (aged 25.95 ± 0.84 years were randomized into two groups: without Blood Flow Restriction (NFR, n = 6 and With Blood Flow Restriction (WFR, n = 6 that performed a series of free weight squats with 80% 1-RM until concentric failure. The strength of the quadriceps extensors was assessed in a maximum voluntary isometric contraction integrated to signals from the surface electromyogram. The average frequency showed significant reductions in the WFR group for the vastus lateralis and vastus medialis muscles, and intergroup only for the vastus medialis. In conclusion, a set of squats at high intensity with BFR could compromise muscle strength immediately after exercise, however, differences were not significant between groups.

  10. Recovery of a soil under different vegetation one year after a high intensity wildfire

    Directory of Open Access Journals (Sweden)

    A. Martín

    2013-05-01

    Full Text Available Studies on soil recovery in fragile ecosystems following high intensity wildfires are scarce. The aim of the present investigation is to evaluate the impact of a high intensity wildfire in an ecosystem under different vegetation (shrubland and pinewood located at Vilardevós (Galicia, NW Spain and highly susceptible to suffer soil erosion due to the steep relief and high erositivity of the rainfall. Soil samples were collected from the A horizon (0-5 cm 1 year after the fire and soil quality was evaluated by analysis of several physical, chemical and biochemical properties measured in the fraction chemical properties > physical properties. The data also showed that the fire impact was different depending on the soil vegetation considered (shrubland and pinewood. Moreover, the data confirmed the slow soil recovery in this fragile ecosystem and, therefore, the need of adopting post-fire stabilisation and rehabilitation treatments in order to minimize the post-fire erosion and soil degradation.

  11. Current status of high-intensity focused ultrasound for the management of uterine adenomyosis

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Vincent Y. T. [Dept. of Obstetrics and Gynaecology, Queen Mary Hospital, The University of Hong Kong, Hong Kong (China)

    2017-04-15

    While high-intensity focused ultrasound has been used for some time in the management of uterine fibroids, its effectiveness and safety in managing adenomyosis is less well established. A literature review was performed of all eligible reports using this modality as a treatment for adenomyosis. Relevant publications were obtained from the PubMed electronic database from inception through March 2016. Eleven articles, including information from 1,150 treatments and follow-up data from 990 patients, were reviewed. High-intensity focused ultrasound appears to be effective and safe in the management of symptomatic adenomyosis, and can be considered as an alternative uterine-sparing option for women with this condition.

  12. Specificity of high-intensity intermittent action remains important to MMA athletes' physical conditioning: response to Paillard (2011).

    Science.gov (United States)

    Del Vecchio, Fabrício Boscolo; Franchini, Emerson

    2013-02-01

    This response to Paillard (2011) focuses on the intermittent nature of mixed martial arts (MMA). It also emphasizes that the main goal of MMA athletes is to win by knockout or submission and that these actions normally are high-intensity actions or preceded by high-intensity actions. Additionally, there is evidence that high-intensity intermittent exercise protocols are able to improve aerobic fitness. It is important only to adjust physical training to the athletes' techniques and tactics.

  13. Ion source choices - an h- source for the high intensity neutrino source

    Energy Technology Data Exchange (ETDEWEB)

    Moehs, Douglas P.; /Fermilab; Welton, Robert F.; /SNS Project, Oak Ridge; Stockli, Martin P.; Peters, Jens; /DESY; Alessi, James; /Brookhaven

    2006-08-01

    The High Intensity Neutrino Source (HINS) program at Fermilab (formerly the Proton Driver) aims to develop a multi-mission linear accelerator (LINAC) capable of accelerate H{sup -} ions to 8 GeV. This paper touches on the ion source requirements for the HINS and discusses long pulse length testing of three ion sources which appear to have the capability of meeting these requirements.

  14. Proceedings of the third ICFA mini-workshop on high intensity, high brightness hadron accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Roser, T.

    1997-11-01

    The third mini-workshop on high intensity, high brightness hadron accelerators was held at Brookhaven National Laboratory on May 7-9, 1997 and had about 30 participants. The workshop focussed on rf and longitudinal dynamics issues relevant to intense and/or bright hadron synchrotrons. A plenary session was followed by four sessions on particular topics. This document contains copies of the viewgraphs used as well as summaries written by the session chairs.

  15. Lymphocyte Redox Imbalance and Reduced Proliferation after a Single Session of High Intensity Interval Exercise

    OpenAIRE

    Tossige-Gomes, Rosalina; Costa, Karine Beatriz; Ottone, Vinícius de Oliveira; Magalhães, Flávio de Castro; Amorim, Fabiano Trigueiro; Rocha-Vieira, Etel

    2016-01-01

    This study investigated whether an acute session of high-intensity interval training (HIIT) is sufficient to alter lymphocyte function and redox status. Sixteen young healthy men underwent a HIIT session on a cycloergometer, consisting of eight bouts of 1 min at 90–100% of peak power, with 75 seconds of active recovery at 30 W between bouts. Venous blood was collected before, immediately after, and 30 minutes after the HIIT session. In response to Staphylococcus aureus superantigen B (SEB) st...

  16. Proceedings of the third ICFA mini-workshop on high intensity, high brightness hadron accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Roser, T.

    1997-11-01

    The third mini-workshop on high intensity, high brightness hadron accelerators was held at Brookhaven National Laboratory on May 7-9, 1997 and had about 30 participants. The workshop focussed on rf and longitudinal dynamics issues relevant to intense and/or bright hadron synchrotrons. A plenary session was followed by four sessions on particular topics. This document contains copies of the viewgraphs used as well as summaries written by the session chairs.

  17. High-intensity focused ultrasound to treat primary hyperparathyroidism: a feasibility study in four patients

    DEFF Research Database (Denmark)

    Kovatcheva, Roussanka D; Vlahov, Jordan D; Shinkov, Alexander D;

    2010-01-01

    Many patients with primary hyperparathyroidism either decline or are not candidates for surgical parathyroidectomy. There are drawbacks to medical therapy as well as percutaneous ethanol injection as alternative therapies for primary hyperparathyroidism. Therefore, in this pilot study, our aim...... was to test the feasibility, safety, and efficacy of a newly developed noninvasive high-intensity focused ultrasound (HIFU) technique for the nonsurgical management of primary hyperparathyroidism....

  18. High-intensity exercise training produces morphological and biochemical changes in adrenal gland of mice.

    Science.gov (United States)

    Bartalucci, A; Ferrucci, M; Fulceri, F; Lazzeri, G; Lenzi, P; Toti, L; Serpiello, F R; La Torre, A; Gesi, M

    2012-06-01

    The effects of training are dependent on complex, adaptive changes which are induced by acute physical exercise at different levels. In particular, evidence shows that the hypothalamus-pituitary-adrenocortical axis, as well as the sympatho-adrenomedullary system, is mainly involved in mediating the physiological effects of physical exercise. The aim of the present study was to investigate, through a morphological and biochemical approach, the effects of training on the adrenal gland of mice, following two different protocols consisting of either low- or high-intensity training. Mice were run daily on a motorised treadmill for 8 weeks, at a velocity corresponding to 60% (low-intensity exercise) or 90% (high-intensity exercise) of the maximal running velocity previously determined by an incremental exercise test. We found that physical exercise produced an increase in the adrenal gland size compared with the control (sedentary) mice. The increase was 31.04% for mice that underwent high-intensity exercise and 10.08% for mice that underwent low intensity exercise, and this appeared to be the result of an increase in the area of both the adrenal cortex and adrenal medulla. Morphological analysis of the adrenal cortex showed that both types of exercise produced an increase in cytoplasmic vacuoles in steroidogenic cells, appearing more abundant after high-intensity exercise. No change was found in the reticulate zone. In the adrenal medulla, despite the absence of morphological changes, immunohistochemistry for tyrosine hydroxylase, dopamine β-hydroxylase and phenyl-ethanolamine-N-methyltransferase demonstrated an increased immunopositivity for these cathecolamine-synthesizing enzymes after intense exercise. These results were confirmed by immunoblot accompanied by densitometric analysis.

  19. High-Intensity Intermittent Swimming Improves Cardiovascular Health Status for Women with Mild Hypertension

    Directory of Open Access Journals (Sweden)

    Magni Mohr

    2014-01-01

    Full Text Available To test the hypothesis that high-intensity swim training improves cardiovascular health status in sedentary premenopausal women with mild hypertension, sixty-two women were randomized into high-intensity (n=21; HIT, moderate-intensity (n=21; MOD, and control groups (n=20; CON. HIT performed 6–10 × 30 s all-out swimming interspersed by 2 min recovery and MOD swam continuously for 1 h at moderate intensity for a 15-week period completing in total 44±1 and 43±1 sessions, respectively. In CON, all measured variables were similar before and after the intervention period. Systolic BP decreased (P<0.05 by 6±1 and 4±1 mmHg in HIT and MOD; respectively. Resting heart rate declined (P<0.05 by 5±1 bpm both in HIT and MOD, fat mass decreased (P<0.05 by 1.1±0.2 and 2.2±0.3 kg, respectively, while the blood lipid profile was unaltered. In HIT and MOD, performance improved (P<0.05 for a maximal 10 min swim (13±3% and 22±3%, interval swimming (23±3% and 8±3%, and Yo-Yo IE1 running performance (58±5% and 45±4%. In conclusion, high-intensity intermittent swimming is an effective training strategy to improve cardiovascular health and physical performance in sedentary women with mild hypertension. Adaptations are similar with high- and moderate-intensity training, despite markedly less total time spent and distance covered in the high-intensity group.

  20. A Mechanism Underlying Preventive Effect of High-Intensity Training on Colon Cancer.

    Science.gov (United States)

    Matsuo, Kaori; Sato, Koji; Suemoto, Ken; Miyamoto-Mikami, Eri; Fuku, Noriyuki; Higashida, Kazuhiko; Tsuji, Katsunori; Xu, Yuzhong; Liu, Xin; Iemitsu, Motoyuki; Hamaoka, Takafumi; Tabata, Izumi

    2017-09-01

    We examined effects of high-intensity training on chemically induced aberrant crypt foci (ACF) in rat colon. We also investigated mechanisms that may underlie the results obtained, with a focus on secreted protein acidic and rich in cysteine (SPARC), which has been proposed as an exercise-related factor of colon cancer prevention. After an administration of 1,2-dimethylhydrazine, F344 rats executed high-intensity intermittent swimming training (HIIST) (twelve 20-s swimming with a weight [16% body weight] with 10-s pauses between the bouts) 5 d·wk for 4 wk. The acute and chronic effects of the HIIST on SPARC were evaluated in rats. We evaluated the in vitro and in vivo effects of 5' AMP-activated protein kinase (AMPK) activator on SPARC in rat serum and epitrochlearis muscle. In human subjects, we determined serum SPARC after exhaustive bicycling consisting of six to seven bouts of exercise at 170% V˙O2max with 10-s rests between the bouts (high-intensity intermittent bicycling [HIIB]). The SPARC mRNA in human vastus lateralis was measured before and after the HIIB for 4 d·wk for 6 wk (HIIB-training [HIIBT]). The numbers of ACF were lower in the HIIST (47 ± 22) compared with the control (122 ± 47) rats (P < 0.05). SPARC in epitrochlearis and serum after HIIS of the trained rat was higher than that in the control resting rats. In vitro and vivo AMPK stimulation increased mRNA and SPARC protein in rat epitrochlearis, respectively. The human serum SPARC after the HIIB was elevated. SPARC mRNA in human muscle was elevated after the HIIBT. The results demonstrated that HIIST inhibits 1,2-dimethylhydrazine-induced colon ACF development. This effect may be explained by SPARC induction by the exercise intensity-related factor AMPK, potentially explaining the preventive effects of high-intensity intermittent exercise training against colon cancer.

  1. MR-guided high-intensity focused ultrasound treatment of uterine fibroids

    OpenAIRE

    2016-01-01

    Antonia Wiggermann,1 Michael Beldoch,1 Friederike Hoellen,2 Peter Hunold1 1Clinic for Radiology and Nuclear Medicine, 2Department of Obstetrics and Gynecology, University Hospital Schleswig-Holstein, Lübeck, Germany Abstract: Uterine fibroids are benign, encapsulated uterine tumors, representing the most common reason for hysterectomy in premenopausal women. High-intensity focused ultrasound (HIFU; also known as focused ultrasound surgery) is a noninvasive technique leading to tissu...

  2. Personalized Metabolomics for Predicting Glucose Tolerance Changes in Sedentary Women After High-Intensity Interval Training

    OpenAIRE

    Kuehnbaum, Naomi L.; Gillen, Jenna B.; Gibala, Martin J.; Britz-McKibbin, Philip

    2014-01-01

    High-intensity interval training (HIIT) offers a practical approach for enhancing cardiorespiratory fitness, however its role in improving glucose regulation among sedentary yet normoglycemic women remains unclear. Herein, multi-segment injection capillary electrophoresis-mass spectrometry is used as a high-throughput platform in metabolomics to assess dynamic responses of overweight/obese women (BMI > 25, n = 11) to standardized oral glucose tolerance tests (OGTTs) performed before and after...

  3. A Rectourethral Fistula due to Transrectal High-Intensity Focused Ultrasound Treatment: Diagnosis and Management

    OpenAIRE

    2012-01-01

    Colovesical fistula (CVF) is an abnormal connection between the enteric and the urinary systems. The rectourethral fistula (RUF) is a possible but extremely rare complication of treatment of prostate cancer with “transrectal High-Intensity Focused Ultrasound (HIFU) treatment.” We present a case of CVF due to HIFU treatment of recurrent prostate cancer. The case was assessed with cystography completed with a pelvic CT scan—with MPR, MIP, and VR reconstruction—before emptying the bladder. Since...

  4. Report from the NSLS workshop: Sources and applications of high intensity uv-vuv light

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, E.D.; Hastings, J.B. [eds.

    1990-12-31

    A workshop was held to evaluate sources and applications of high intensity, ultra violet (UV) radiation for biological, chemical, and materials sciences. The proposed sources are a UV free electron laser (FEL) driven by a high brightness linac and undulators in long, straight sections of a specially designed low energy (400 MeV) storage ring. These two distinct types of sources will provide a broad range of scientific opportunities that were discussed in detail during the workshop.

  5. Report from the NSLS workshop: Sources and applications of high intensity uv-vuv light

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, E.D.; Hastings, J.B. (eds.)

    1990-01-01

    A workshop was held to evaluate sources and applications of high intensity, ultra violet (UV) radiation for biological, chemical, and materials sciences. The proposed sources are a UV free electron laser (FEL) driven by a high brightness linac and undulators in long, straight sections of a specially designed low energy (400 MeV) storage ring. These two distinct types of sources will provide a broad range of scientific opportunities that were discussed in detail during the workshop.

  6. High-intensity cycle interval training improves cycling and running performance in triathletes.

    Science.gov (United States)

    Etxebarria, Naroa; Anson, Judith M; Pyne, David B; Ferguson, Richard A

    2014-01-01

    Effective cycle training for triathlon is a challenge for coaches. We compared the effects of two variants of cycle high-intensity interval training (HIT) on triathlon-specific cycling and running. Fourteen moderately-trained male triathletes ([Formula: see text]O2peak 58.7 ± 8.1 mL kg(-1) min(-1); mean ± SD) completed on separate occasions a maximal incremental test ([Formula: see text]O2peak and maximal aerobic power), 16 × 20 s cycle sprints and a 1-h triathlon-specific cycle followed immediately by a 5 km run time trial. Participants were then pair-matched and assigned randomly to either a long high-intensity interval training (LONG) (6-8 × 5 min efforts) or short high-intensity interval training (SHORT) (9-11 × 10, 20 and 40 s efforts) HIT cycle training intervention. Six training sessions were completed over 3 weeks before participants repeated the baseline testing. Both groups had an ∼7% increase in [Formula: see text]O2peak (SHORT 7.3%, ±4.6%; mean, ±90% confidence limits; LONG 7.5%, ±1.7%). There was a moderate improvement in mean power for both the SHORT (10.3%, ±4.4%) and LONG (10.7%, ±6.8%) groups during the last eight 20-s sprints. There was a small to moderate decrease in heart rate, blood lactate and perceived exertion in both groups during the 1-h triathlon-specific cycling but only the LONG group had a substantial decrease in the subsequent 5-km run time (64, ±59 s). Moderately-trained triathletes should use both short and long high-intensity intervals to improve cycling physiology and performance. Longer 5-min intervals on the bike are more likely to benefit 5 km running performance.

  7. Repeated high-intensity running and sprinting in elite women’s soccer competition

    OpenAIRE

    Gabbett, Tim J; Wiig, Håvard; Spencer, Matt

    2013-01-01

    Background: To the authors’ knowledge, no study has investigated the concurrent repeated, high-intensity (RHIA) and repeated-sprint activity (RSA) of intermittent team-sport competition. Purpose: In this study, they report on the RSA of elite women’s football competition. In addition, they describe the nature of RHIA (eg, striding and sprinting activities) that involve a high energy cost and are associated with short (ie, ≤20 s) recovery periods. Methods: Thirteen elite women soccer players u...

  8. Circulating adiponectin concentration and body composition are altered in response to high-intensity interval training.

    Science.gov (United States)

    Shing, Cecilia M; Webb, Jessica J; Driller, Matthew W; Williams, Andrew D; Fell, James W

    2013-08-01

    Adiponectin influences metabolic adaptations that would prove beneficial to endurance athletes, and yet to date there is little known about the response of adiponectin concentrations to exercise, and, in particular, the response of this hormone to training in an athlete population. This study aimed to determine the response of plasma adiponectin concentrations to acute exercise after 2 different training programs and to determine the influence of the training on body composition. Seven state-level representative rowers (age: 19 ± 1.2 years [mean ± SD], height: 1.77 ± 0.10 m, body mass: 74.0 ± 10.7 kg, VO2peak 62.1 ± 7.0 ml·kg·min) participated in the double-blind, randomized crossover investigation. Rowers performed an incremental graded exercise test before and after completing 4 weeks of high-intensity interval ergometer training and 4 weeks of traditional ergometer rowing training. Rowers' body composition was assessed at baseline and after each training program. Significant increases in plasma adiponectin concentration occurred in response to maximal exercise after completion of the high-intensity interval training (p = 0.016) but not after traditional ergometer rowing training (p = 0.69). The high-intensity interval training also resulted in significant increases in mean 4-minute power output (p = 0.002) and VO2peak (p = 0.05), and a decrease in body fat percentage (p = 0.022). Mean 4-minute power output, VO2peak, and body fat percentage were not significantly different after 4 weeks of traditional ergometer rowing training (p > 0.05). Four weeks of high-intensity interval training is associated with an increase in adiponectin concentration in response to maximal exercise and a reduction in body fat percentage. The potential for changes in adiponectin concentration to reflect positive training adaptations and athlete performance level should be further explored.

  9. A Highly intense DC muon source, MuSIC and muon CLFV search

    Science.gov (United States)

    Hino, Y.; Kuno, Y.; Sato, A.; Sakamoto, H.; Matsumoto, Y.; Tran, N. H.; Hashim, I. H.; Fukuda, M.; Hayashida, Y.; Ogitsu, T.; Yamamoto, A.; Yoshida, M.

    2014-08-01

    MuSIC is a new muon facility, which provides the world's highest intense muon beam with continuous time structure at Research Center of Nuclear Physics (RCNP), Osaka University. It's intensity is designed to be 108 muons per second with only 0.4 kW proton beam. Such a high intense muon beam is very important for searches of rare decay processes, for example search for the muon to electron conversion.

  10. Design concept of radiation control system for the high intensity proton accelerator facility

    CERN Document Server

    Miyamoto, Y; Harada, Y; Ikeno, K

    2002-01-01

    Description is given for the characteristic radiation environment for the High Intensity Proton Accelerator Facility and the design concept of the radiation control system of it. The facility is a large scale accelerator complex consisting of high energy proton accelerators carrying the highest beam intensity in the world and the related experimental facilities and therefore provides various issues relevant to the radiation environment. The present report describes the specifications for the radiation control system for the facility, determined in consideration of these characteristics.

  11. Laser-enhanced cavitation during high intensity focused ultrasound: An in vivo study

    OpenAIRE

    Cui, Huizhong; Zhang, Ti; Yang, Xinmai

    2013-01-01

    Laser-enhanced cavitation during high intensity focused ultrasound (HIFU) was studied in vivo using a small animal model. Laser light was employed to illuminate the sample concurrently with HIFU radiation. The resulting cavitation was detected with a passive cavitation detector. The in vivo measurements were made under different combinations of HIFU treatment depths, laser wavelengths, and HIFU durations. The results demonstrated that concurrent light illumination during HIFU has the potentia...

  12. A Highly intense DC muon source, MuSIC and muon CLFV search

    Energy Technology Data Exchange (ETDEWEB)

    Hino, Y.; Kuno, Y.; Sato, A. [Department of Physics, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Sakamoto, H. [Department of Physics, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Research Center of Nuclear Physics, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Matsumoto, Y.; Tran, N.H.; Hashim, I.H. [Department of Physics, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Fukuda, M.; Hayashida, Y. [Research Center of Nuclear Physics, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Ogitsu, T.; Yamamoto, A.; Yoshida, M. [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2014-08-15

    MuSIC is a new muon facility, which provides the world's highest intense muon beam with continuous time structure at Research Center of Nuclear Physics (RCNP), Osaka University. It's intensity is designed to be 10{sup 8} muons per second with only 0.4 kW proton beam. Such a high intense muon beam is very important for searches of rare decay processes, for example search for the muon to electron conversion.

  13. The effects of light emitting diode therapy following high intensity exercise.

    Science.gov (United States)

    Denis, Romain; O'Brien, Christopher; Delahunt, Eamonn

    2013-05-01

    To determine the effects of light emitting diode therapy (LEDT) irradiation on blood lactate concentration ([La]) clearance, peak power output and fatigue index (FI) following high intensity fatiguing exercise. Single-blinded randomised cross-over placebo controlled trial. University College Dublin, Institute for Sport and Health, Human performance laboratory. Eighteen healthy male athletes were recruited from field-based sports (including soccer, hockey and rugby union) and participated in the present study. Dependent variables were the peak power output elicited during the Wingate Anaerobic Test (WAnT), FI and [La] before and after each exercise. WAnT performance was measured prior to high intensity fatiguing exercise (Yo-Yo IR2), prior to LEDT or placebo, and following LEDT or placebo. [La] was measured at baseline, immediately after the Yo-Yo IR2, and in the 3rd, 9th, and 15th min following LEDT or placebo condition. No significant group by treatment interactions were observed for any outcome measures (P > 0.05). We conclude that LEDT irradiation applied following high intensity exercise was not effective and has no immediate effect on [La] clearance, peak power and FI, and thus has no significant effect on muscle recovery in athletes at the intensity and irradiation parameters used in the present study. Further research using different parameters is required to determine how LEDT may contribute to post-exercise recovery. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. High intensity aerobic interval training improves peak oxygen consumption in patients with metabolic syndrome: CAT

    Directory of Open Access Journals (Sweden)

    Alexis Espinoza Salinas

    2014-06-01

    Full Text Available Introduction A number of cardiovascular risk factors characterizes the metabolic syndrome: insulin resistance (IR, low HDL cholesterol and high triglycerides. The aforementioned risk factors lead to elevated levels of abdominal adipose tissue, resulting in oxygen consumption deficiency. Purpose To verify the validity and applicability of using high intensity interval training (HIIT in subjects with metabolic syndrome and to answer the following question: Can HIIT improve peak oxygen consumption? Method The systematic review "Effects of aerobic interval training on exercise capacity and metabolic risk factors in individuals with cardiometabolic disorders" was analyzed. Results Data suggests high intensity aerobic interval training increases peak oxygen consumption by a standardized mean difference of 3.60 mL/kg-1/min-1 (95% confidence interval, 0.28-4.91. Conclusion In spite of the methodological shortcomings of the primary studies included in the systematic review, we reasonably conclude that implementation of high intensity aerobic interval training in subjects with metabolic syndrome, leads to increases in peak oxygen consumption.

  15. Dose estimation and shielding calculation for X-ray hazard at high intensity laser facilities

    Science.gov (United States)

    Qiu, Rui; Zhang, Hui; Yang, Bo; James, C. Liu; Sayed, H. Rokni; Michael, B. Woods; Li, Jun-Li

    2014-12-01

    An ionizing radiation hazard produced from the interaction between high intensity lasers and solid targets has been observed. Laser-plasma interactions create “hot” electrons, which generate bremsstrahlung X-rays when they interact with ions in the target. However, up to now only limited studies have been conducted on this laser-induced radiological protection issue. In this paper, the physical process and characteristics of the interaction between high intensity lasers and solid targets are analyzed. The parameters of the radiation sources are discussed, including the energy conversion efficiency from laser to hot electrons, hot electron energy spectrum and electron temperature, and the bremsstrahlung X-ray energy spectrum produced by hot electrons. Based on this information, the X-ray dose generated with high-Z targets for laser intensities between 1014 and 1020 W/cm2 is estimated. The shielding effects of common shielding items such as the glass view port, aluminum chamber wall and concrete wall are also studied using the FLUKA Monte Carlo code. This study provides a reference for the dose estimation and the shielding design of high intensity laser facilities.

  16. Postprandial lipoprotein profile in two modes of high-intensity intermittent exercise

    Science.gov (United States)

    Panissa, Valéria Leme Gonçalves; Julio, Ursula Ferreira; Diniz, Tiego Aparecido; de Moura Mello Antunes, Barbara; Lira, Fabio Santos; Takito, Monica Yuri; Franchini, Emerson

    2016-01-01

    The aim of present study was to compare blood lipid postprandial profile response in two modes of high-intensity intermittent exercise. Twelve individuals (6 men and 6 women) were submitted to a maximal incremental test (to determine maximal aerobic power [MAP] and V. O2peak [peak oxygen uptake]), high-intensity intermittent all-out exercise (60×8-sec bouts interspersed by 12-sec passive recovery) and fixed high-intensity intermittent exercise (100% maximal aerobic speed, consisted of 1-min repetitions at MAP [70 rpm] separated by 1-min of passive recovery). Blood samples were collected pre, immediately, 45 and 90-min postexercise. Serum was analyzed for total cholesterol and its ratio, high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), very low-density lipoprotein (VLDL) cholesterol, and triacylglycerol (TAG). For TAG there was a main effect of moment with higher values immediately postexercise compared to 45-min postexercise. For VLDL there was a main effect to moment with higher values immediately post exercise than pre and 45-min postexercise; higher values 90-min postexercise than 45-min postexercise. There was no effect for HDL-c, LDL-c, and cholesterol. For area under the curve there was no difference for any variable. Our results indicated that both kinds of acute exercise session lead to no improvement in the acute response of serum lipid profile of healthy young. PMID:27807528

  17. Nutritional strategies to support adaptation to high-intensity interval training in team sports.

    Science.gov (United States)

    Gibala, Martin J

    2013-01-01

    Team sports are characterized by intermittent high-intensity activity patterns. Typically, play consists of short periods of very intense or all-out efforts interspersed with longer periods of low-intensity activity. Fatigue is a complex, multi-factorial process, but intense intermittent exercise performance can potentially be limited by reduced availability of substrates stored in skeletal muscle and/or metabolic by-products associated with fuel breakdown. High-intensity interval training (HIT) has been shown to induce adaptations in skeletal muscle that enhance the capacity for both oxidative and non-oxidative metabolism. Nutrient availability is a potent modulator of many acute physiological responses to exercise, including various molecular signaling pathways that are believed to regulate cellular adaptation to training. Several nutritional strategies have also been reported to acutely alter metabolism and enhance intermittent high-intensity exercise performance. However, relatively little is known regarding the effect of chronic interventions, and whether supplementation over a period of weeks or months augments HIT-induced physiological remodeling and promotes greater performance adaptations. Theoretically, a nutritional intervention could augment HIT adaptation by improving energy metabolism during exercise, which could facilitate greater total work and an enhanced chronic training stimulus, or promoting some aspect of the adaptive response during recovery, which could lead to enhanced physiological adaptations over time.

  18. The effect of an intermittent, high-intensity warm-up on supramaximal kayak ergometer performance.

    Science.gov (United States)

    Bishop, David; Bonetti, Darrel; Spencer, Matthew

    2003-01-01

    It has previously been shown that the metabolic acidaemia induced by a continuous warm-up at the 'lactate threshold' is associated with a reduced accumulated oxygen deficit and decreased supramaximal performance. The aim of this study was to determine if an intermittent, high-intensity warm-up could increase oxygen uptake (VO2) without reducing the accumulated oxygen deficit, and thus improve supramaximal performance. Seven male 500 m kayak paddlers, who had represented their state, volunteered for this study. Each performed a graded exercise test to determine VO2max and threshold parameters. On subsequent days and in a random, counterbalanced order, the participants then performed a continuous or intermittent, high-intensity warm-up followed by a 2 min, all-out kayak ergometer test. The continuous warm-up consisted of 15 min of exercise at approximately 65% VO2max. The intermittent, high-intensity warm-up was similar, except that the last 5 min was replaced with five 10 s sprints at 200% VO2max, separated by 50 s of recovery at approximately 55% VO2max. Significantly greater (P kayak ergometer performance is significantly better after an intermittent rather than a continuous warm-up.

  19. Repeated High Intensity Bouts with Long Recovery: Are Bicarbonate or Carbohydrate Supplements an Option?

    Directory of Open Access Journals (Sweden)

    Thomas Stöggl

    2014-01-01

    Full Text Available The effects of varying recovery modes and the influence of preexercise sodium bicarbonate and carbohydrate ingestion on repeated high intensity performance, acid-base response, and recovery were analyzed in 12 well-trained males. They completed three repeated high intensity running bouts to exhaustion with intervening recovery periods of 25 min under the following conditions: sodium bicarbonate, active recovery (BIC; carbohydrate ingestion, active recovery (CHO; placebo ingestion, active recovery (ACTIVE; placebo ingestion, passive recovery (PASSIVE. Blood lactate (BLa, blood gases, heart rate, and time to exhaustion were collected. The three high intensity bouts had a duration of 138±9, 124±6, and 121±6 s demonstrating a decrease from bout 1 to bout 3. Supplementation strategy had no effect on performance in the first bout, even with differences in pH and bicarbonate (HCO3-. Repeated sprint performance was not affected by supplementation strategy when compared to ACTIVE, while PASSIVE resulted in a more pronounced decrease in performance compared with all other interventions. BIC led to greater BLa, pH, and HCO3- values compared with all other interventions, while for PASSIVE the opposite was found. BLa recovery was lowest in PASSIVE; recovery in pH, and HCO3- was lower in PASSIVE and higher in BIC.

  20. Influence of repeated bouts of eccentric exercise on high-intensity aerobic performance.

    Science.gov (United States)

    Higino, Wonder Passoni; Aparecido de Souza, Renato; Cavalcanti, Fabio de Sousa; Cardoso, Anderlei Dos Santos; Vasconcelos, Murilo Victor; Fernandes da Silva, Fabiano; Leme, José Alexandre C A

    2016-08-01

    [Purpose] It is believed that eccentric high-intensity exercise can decrease performance in subsequent exercise. However, with repetition, the deleterious effects can be minimized. Thus, this study evaluated the influence of repeated bouts of eccentric exercise on subsequent high-intensity aerobic performance. [Subjects and Methods] Seven healthy and sedentary male volunteers were recruited. a) Visit 1: determination of maximum oxygen uptake (VO2max) and speed associated with maximum oxygen uptake (vVO2max) in incremental treadmill testing; b) Visit 2: run to exhaustion at vVO2max (Tlim control); c) Visit 3: 10 sets of 10 depth jumps, followed by a run to exhaustion at vVO2max (Tlim 1); d) Visit 4: after 6 weeks without any physical training, the volunteers carried out the same procedures as on the third visit (Tlim 2). Data were analyzed using one-way analysis of variance (ANOVA) with the post-hoc Tukey test. [Results] Significant differences were found between Tlim control and Tlim 1 (283.4 ± 47.7 s vs. 125.2 ± 64.1 s, respectively), these were not different from Tlim 2. [Conclusion] Eccentric exercise showed deleterious effects on subsequent high-intensity aerobic performance. These effects were minimized after the exercise protocol was repeated 6 weeks after the first event.

  1. Joint Cooling does not Hinder Athletic Performance during High-intensity Intermittent Exercise.

    Science.gov (United States)

    Kim, H; Lee, D; Choi, H-M; Park, J

    2016-07-01

    We examined the effects of ankle and knee joint cooling on 20-m sprint times and maximal vertical jump heights during high-intensity intermittent exercise. 21 healthy collegiate male basketball (n=14) and handball players (n=7) underwent 3 experimental sessions. Each session consisted of four 15-min quarters of high-intensity intermittent exercises including various intensities of 20-m shuttle running and jumping. A 20-min bilateral joint cooling (ankle, knee, or control-no cooling: in a counterbalanced order) was applied before quarters 1 and 3. After joint cooling, no warm-up activity other than the exercise protocol was given. The 20-m sprint times and maximal vertical jump heights in each experimental session were recorded at baseline (prior to quarter-1) and during each quarter. To test joint cooling effects over time, we performed 3×5 mixed model ANOVAs. Neither ankle nor knee joint cooling changed 20-m sprint times (F8,280=1.45; p=0.18) or maximal vertical jump heights (F8,280=0.76; p=0.64). However, a trend was observed in which joint cooling immediately decreased (quarters 1 and 3) but active warm-up for approximately 20 min improved 20-min sprint times (quarters 2 and 4). Our study suggests that athletic performance such as sprinting and jumping are not altered by joint cooling applied prior to or during high-intensity intermittent exercise.

  2. Hot electron generation and energy coupling in planar experiments with shock ignition high intensity lasers

    Science.gov (United States)

    Wei, M. S.; Krauland, C.; Alexander, N.; Zhang, S.; Peebles, J.; Beg, F. N.; Theobald, W.; Borwick, E.; Ren, C.; Yan, R.; Haberberger, D.; Betti, R.; Campbell, E. M.

    2016-10-01

    Hot electrons produced in nonlinear laser plasma interactions are critical issues for shock ignition (SI) laser fusion. We conducted planar target experiments to characterize hot electron and energy coupling using the high energy OMEGA EP laser system at SI high intensities. Targets were multilayered foils consisting of an ablator (either plastic or lithium) and a Cu layer to facilitate hot electron detection via fluorescence and bremsstrahlung measurements. The target was first irradiated by multi-kJ, low-intensity UV beams to produce a SI-relevant mm-scale hot ( 1 keV) preformed plasma. The main interaction pulse, either a kJ 1-ns UV pulse with intensity 1.6x1016 Wcm-2 or a kJ 0.1-ns IR pulse with intensity up to 2x1017 Wcm-2was injected at varied timing delays. The high intensity IR beam was found to strongly interact with underdense plasmas breaking into many filaments near the quarter critical density region followed by propagation of those filaments to critical density, producing hot electrons with Thot 70 keV in a well-contained beam. While the high intensity UV beam showed poor energy coupling. Details of the experiments and the complementary PIC modeling results will be presented. Work supported by U.S. DOE under contracts DE-NA0002730 (NLUF) and DE-SC0014666 (HEDLP).

  3. Changes in technique and efficiency after high-intensity exercise in cross-country skiers.

    Science.gov (United States)

    Åsan Grasaas, Christina; Ettema, Gertjan; Hegge, Ann Magdalen; Skovereng, Knut; Sandbakk, Øyvind

    2014-01-01

    This study investigated changes in technique and efficiency after high-intensity exercise to exhaustion in elite cross-country skiers. Twelve elite male skiers completed 4 min submaximal exercise before and after a high-intensity incremental test to exhaustion with the G3 skating technique on a 5% inclined roller-ski treadmill. Kinematics and kinetics were monitored by instrumented roller skis, work rate was calculated as power against roller friction and gravity, aerobic metabolic cost was determined from gas exchange, and blood lactate values indicated the anaerobic contribution. Gross efficiency was the work rate divided by aerobic metabolic rate. A recovery period of 10 min between the incremental test and the posttest was included to allow the metabolic values to return to baseline. Changes in neuromuscular fatigue in upper and lower limbs before and after the incremental test were indicated by peak power in concentric bench press and squat-jump height. From pretest to posttest, cycle length decreased and cycle rate increased by approximately 5% (P ski forces did not change significantly. Oxygen uptake increased by 4%, and gross efficiency decreased from 15.5% ± 0.7% to 15.2% ± 0.5% from pretest to posttest (both P cross-country skiers demonstrated a less efficient technique and shorter cycle length during submaximal roller-ski skating after high-intensity exercise. However, there were no changes in ski forces or peak power in the upper and lower limbs that could explain these differences.

  4. Benefits of High-Intensity Intensive Care Unit Physician Staffing under the Affordable Care Act

    Directory of Open Access Journals (Sweden)

    Sachin Logani

    2011-01-01

    Full Text Available The Affordable Care Act signed into law by President Obama, with its value-based purchasing program, is designed to link payment to quality processes and outcomes. Treatment of critically ill patients represents nearly 1% of the gross domestic product and 25% of a typical hospital budget. Data suggest that high-intensity staffing patterns in the intensive care unit (ICU are associated with cost savings and improved outcomes. We evaluate the literature investigating the cost-effectiveness and clinical outcomes of high-intensity ICU physician staffing as recommended by The Leapfrog Group (a consortium of companies that purchase health care for their employees and identify ways to overcome barriers to nationwide implementation of these standards. Hospitals that have implemented the Leapfrog initiative have demonstrated reductions in mortality and length of stay and increased cost savings. High-intensity staffing models appear to be an immediate cost-effective way for hospitals to meet the challenges of health care reform.

  5. HIGH INTENSITY EXERCISE AND FLEXIBILITY OF THE LOWER LIMBS: DOSE-EFFECT STUDY

    Directory of Open Access Journals (Sweden)

    João Rafael Valentim-Silva

    Full Text Available ABSTRACT Introduction: Sports scientists have been studying the phenomenon involving different types of exercises and their influence on other activities. Stretching exercises have a negative influence on muscular strength and power output, as do high intensity or long duration cardiovascular training. Nevertheless, several studies have found the opposite to be true Nevertheless, few investigations have studied the opposite. Objective: To determine whether high intensity power exercise influences muscular flexibility in an acute manner. Methods: A sample of forty-three male and female young adults aged between 18 and 28 years, with a mean age of 22.88 + 3.04 years, who have practiced physical activity for at least six months. To determine flexibility, the sit-and-reach test was used. For the high intensity training, a 45º leg press was used. A 10-rep movement was performed at 85% of 1 RM, in both pre- and post-tests. Statistic analysis was conducted using the ANOVA and Scheffer's post-hoc tests, with a level of significance for differences of < 0.05. Results: Comparison of the pre- and post-tests proved to be statistically significant from the baseline from the fourth to the seventh repetitions. Conclusion: Strength exercises at 85% of 1RM seem to significantly increase range of motion in an acute manner, and the growth of this range of motion has a dose-effect response.

  6. Perceptual feeling and time-of-day effects on high intensity exercise performance

    Directory of Open Access Journals (Sweden)

    MARIE CLARE MCCORMICK

    2012-01-01

    Full Text Available The present study was designed to investigate the effect of time of day and perceptual feeling on high intensity cycle ergometry and related performance during ‘normal working hours’. Eleven male participants (22.9 ± 2.6yrs; 182 ± 0.06cm; 80.43 ± 14.39kg were tested over a 12 h period (08:00-20:00 h. Every hour, on the hour, participants performed a 10s maximal leg cycle ergometry test and completed an Exercise-Induced Feeling Inventory (EFI; every hour, on the half hour, they performed a standing broad jump (SBJ, hand grip test (HG and vertical jump (VJ. Participants were instructed that each test required maximum effort. The main results show that there were no significant differences during the 12h experimental period in any of the performance variables (P > 0.05. However, peak power output during the high intensity cycle ergometry and distance and height achieved during the SBJ and VJ test along with positive engagement all peaked at 19:00h. The results show that high intensity cycle ergometry and related physiological measures are not affected by the time of day during ‘normal working hours’. However, the data suggests that maximal performance is moderately affected by motivational levels of participants and therefore when using maximal exercise tests investigators should ensure that participants are highly motivated.

  7. Rapid response of soil fungal communities to low and high intensity fire

    Science.gov (United States)

    Smith, Jane E.; Cowan, Ariel D.; Reazin, Chris; Jumpponen, Ari

    2016-04-01

    Contemporary fires have created high-severity burn areas exceeding historical distributions in forests in the western United States. Until recently, the response of soil ecosystems to high intensity burns has been largely unknown. In complementary studies, we investigated the environmental effect of extreme soil heating, such that occurs with the complete combustion of large down wood during wildfires, on soil fungi and nutrients. We used TRFLP and next generation sequencing (Illumina MiSeq) to investigate the fungal communities. During the burning of large down wood, temperatures lethal to fungi were detected at 0-cm, 5-cm, and 10-cm depths in soils compared to 0-cm depth in soils receiving low intensity broadcast burns. We compared the soil fungal diversity in ten high intensity burned plots paired with adjacent low intensity burned plots before and one week after at 0-10 cm soil depth. Nonmetric Multidimensional Scaling (NMS) ordinations and analyses of taxon frequencies reveal a substantial community turnover and corresponding near complete replacement of the dominant basidiomycetes by ascomycetes in high intensity burns. These coarse-level taxonomic responses were primarily attributable to a few fire-responsive (phoenicoid) fungi, particularly Pyronema sp. and Morchella sp., whose frequencies increased more than 100-fold following high intensity burns. Pinus ponderosa seedlings planted one week post-burn were harvested after four months for EMF root tip analysis. We found: a) greater differences in soil properties and nutrients in high intensity burned soils compared to low intensity burned and unburned soils; b) no differences in EMF richness and diversity; and c) weak differences in community composition based on relative abundance between unburned and either burn treatments. These results confirm the combustion of large downed wood can alter the soil environment directly beneath it. However, an EMF community similar to low burned soils recolonized high

  8. SALIVARY CORTISOL RESPONSES AND PERCEIVED EXERTION DURING HIGH INTENSITY AND LOW INTENSITY BOUTS OF RESISTANCE EXERCISE

    Directory of Open Access Journals (Sweden)

    Alison D. Egan

    2004-03-01

    Full Text Available The purpose of this study was to measure the salivary cortisol response to different intensities of resistance exercise. In addition, we wanted to determine the reliability of the session rating of perceived exertion (RPE scale to monitor resistance exercise intensity. Subjects (8 men, 9 women completed 2 trials of acute resistance training bouts in a counterbalanced design. The high intensity resistance exercise protocol consisted of six, ten-repetition sets using 75% of one repetition maximum (RM on a Smith machine squat and bench press exercise (12 sets total. The low intensity resistance exercise protocol consisted of three, ten-repetition sets at 30% of 1RM of the same exercises as the high intensity protocol. Both exercise bouts were performed with 2 minutes of rest between each exercise and sessions were repeated to test reliability of the measures. The order of the exercise bouts was randomized with least 72 hours between each session. Saliva samples were obtained immediately before, immediately after and 30 mins following each resistance exercise bout. RPE measures were obtained using Borg's CR-10 scale following each set. Also, the session RPE for the entire exercise session was obtained 30 minutes following completion of the session. There was a significant 97% increase in the level of salivary cortisol immediately following the high intensity exercise session (P<0.05. There was also a significant difference in salivary cortisol of 145% between the low intensity and high intensity exercise session immediately post-exercise (P<0.05. The low intensity exercise did not result in any significant changes in cortisol levels. There was also a significant difference between the session RPE values for the different intensity levels (high intensity 7.1 vs. low intensity 1.9 (P<0.05. The intraclass correlation coefficient for the session RPE measure was 0.95. It was concluded that the session RPE method is a valid and reliable method of

  9. High-intensity Exercise in Men with Type 1 Diabetes and Mode of Insulin Therapy.

    Science.gov (United States)

    Gawrecki, Andrzej; Naskret, Dariusz; Niedzwiecki, Pawel; Duda-Sobczak, Anna; Araszkiewicz, Aleksandra; Zozulinska-Ziolkiewicz, Dorota

    2017-04-01

    The purpose of this study was to evaluate the impact of high intensity exercise on glucose levels and risk of metabolic decompensation in males with type 1 diabetes (T1D), depending on the method of insulin administration. The study comprised 29 males (aged 25.3±5.1 years; duration of diabetes 10.3±3.2 years) treated with continuous subcutaneous insulin infusion (CSII) or multiple daily insulin injections (MDI). Treadmill exercise test was performed twice in each patient until subjective exhaustion as maximum according to the Borg scale. All the patients achieved ≥85% of the maximal heart rate. Distance during the test was 4 500±1 400 m and 4 473±1 559 m in the MDI and CSII groups, respectively, which was achieved in 31±8 min. During the test and in the 6 h after, no clinically significant episodes of hypoglycemia occurred. Mean glucose levels did not exceed 10 mmol/L in most patients. The risk of the composite endpoint (hypoglycemia2.2 mmol/L) was higher in patients treated with MDI than CSII (OR3.75, 95%CI:1.22-11.52, p=0.02). In conclusion, planned high intensity physical effort in men with well-controlled T1D is metabolically safe. CSII shows greater metabolic advantage over MDI during and after high intensity exercise in men with T1D. © Georg Thieme Verlag KG Stuttgart · New York.

  10. Locomotor muscle fatigue does not alter oxygen uptake kinetics during high-intensity exercise

    Directory of Open Access Journals (Sweden)

    James Hopker

    2016-10-01

    Full Text Available The slow component (VO2sc that develops during high-intensity aerobic exercise is thought to be strongly associated with locomotor muscle fatigue. We sought to experimentally test this hypothesis by pre-fatiguing the locomotor muscles used during subsequent high-intensity cycling exercise. Over two separate visits, eight healthy male participants were asked to either perform a non-metabolically stressful 100 intermittent drop-jumps protocol (pre fatigue condition or rest for 33 minutes (control condition according to a random and counterbalanced order. Locomotor muscle fatigue was quantified with 6-second maximal sprints at a fixed pedaling cadence of 90 rev·min-1. Oxygen kinetics and other responses (heart rate, capillary blood lactate concentration and rating of perceived exertion, RPE were measured during two subsequent bouts of 6 min cycling exercise at 50% of the delta between the lactate threshold and VO2max determined during a preliminary incremental exercise test. All tests were performed on the same cycle ergometer. Despite significant locomotor muscle fatigue (P = 0.03, the VO2sc was not significantly different between the pre fatigue (464 ± 301 mL·min-1 and the control (556 ± 223 mL·min-1 condition (P = 0.50. Blood lactate response was not significantly different between conditions (P = 0.48 but RPE was significantly higher following the pre-fatiguing exercise protocol compared with the control condition (P < 0.01 suggesting higher muscle recruitment. These results demonstrate experimentally that locomotor muscle fatigue does not significantly alter the VO2 kinetic response to high intensity aerobic exercise, and challenge the hypothesis that the VO2sc is strongly associated with locomotor muscle fatigue.

  11. Beetroot Juice Supplementation Improves High-Intensity Intermittent Type Exercise Performance in Trained Soccer Players

    Science.gov (United States)

    Nyakayiru, Jean; Jonvik, Kristin L.; Trommelen, Jorn; Pinckaers, Philippe J. M.; Senden, Joan M.; van Loon, Luc J. C.; Verdijk, Lex B.

    2017-01-01

    It has been shown that nitrate supplementation can enhance endurance exercise performance. Recent work suggests that nitrate ingestion can also increase intermittent type exercise performance in recreational athletes. We hypothesized that six days of nitrate supplementation can improve high-intensity intermittent type exercise performance in trained soccer players. Thirty-two male soccer players (age: 23 ± 1 years, height: 181 ± 1 m, weight: 77 ± 1 kg, playing experience: 15.2 ± 0.5 years, playing in the first team of a 2nd or 3rd Dutch amateur league club) participated in this randomized, double-blind cross-over study. All subjects participated in two test days in which high-intensity intermittent running performance was assessed using the Yo-Yo IR1 test. Subjects ingested nitrate-rich (140 mL; ~800 mg nitrate/day; BR) or a nitrate-depleted beetroot juice (PLA) for six subsequent days, with at least eight days of wash-out between trials. The distance covered during the Yo-Yo IR1 was the primary outcome measure, while heart rate (HR) was measured continuously throughout the test, and a single blood and saliva sample were collected just prior to the test. Six days of BR ingestion increased plasma and salivary nitrate and nitrite concentrations in comparison to PLA (p < 0.001), and enhanced Yo-Yo IR1 test performance by 3.4 ± 1.3% (from 1574 ± 47 to 1623 ± 48 m; p = 0.027). Mean HR was lower in the BR (172 ± 2) vs. PLA trial (175 ± 2; p = 0.014). Six days of BR ingestion effectively improves high-intensity intermittent type exercise performance in trained soccer players. PMID:28327503

  12. Effects of high-intensity swimming training on the bones of ovariectomized rats.

    Science.gov (United States)

    Oh, Taewoong; Tanaka, Sakura; Naka, Tatsuki; Igawa, Shoji

    2016-09-01

    This study was performed to assess the effects of high-intensity intermittent swimming training(HIT) on bone in ovariectomized rats. Six-week-old female Sprague-Dawley rats were randomly assigned to either sham operation or bilateral ovariectomy. After surgery, they were divided into the following four groups: 1) sham-operated sedentary (S), 2) sham-operated exercise training (SE), 3) OVX sedentary (O), 4) OVX exercise training (OE) 5) OVX given 17β-estradiol (OE2) and 6) OVX exercise training and given 17β-estradiol (OEE). SE, OE and OEE rats were used extremely high-intensity swim exercise. The rats repeated fourteen 20-s swimming bouts with a weight equivalent to 14, 15, and 16% of body weight for the first 5, the next 9, and the last 5 days, respectively. Between exercise bouts, a 10-s pause was allowed. HIT was originally designed as an exercise method; a method that very quickly induces an increase in the maximum oxygen intake (Tabata I et al., 1996). OEE and OE2 rats were subcutaneously injected ethanol with 25μg/kg body weight 17β-estradiol 3 times per week. Bone strength, bone mineral density and trabecular bone parameters were measured after a 8-weeks experimental period. Bone strength was significantly higher in the SE, OE, OE2 and OEE group compared with the O group. BV/TV was significant increase in the SE, OE groups compared with the O group. BMD showed no difference in the OE group compared with the O group. This study demonstrate some beneficial effects of postmenopausal osteoporosis of high-intensity intermittent swimming training on bone structure and strength.

  13. Plasma Irisin Modestly Increases during Moderate and High-Intensity Afternoon Exercise in Obese Females

    Science.gov (United States)

    Winn, Nathan C.; Grunewald, Zachary I.; Liu, Ying; Heden, Timothy D.; Nyhoff, Lauren M.; Kanaley, Jill A.

    2017-01-01

    Background and Purpose Irisin is an exercise-responsive myokine that has been proposed to exert anti-obesity benefits; yet its response during exercise in obese women is not described. This study characterized plasma irisin levels during a single bout of afternoon isocaloric-exercise of different intensities (moderate- vs high-intensity) in obese females. Methods Eleven obese females participated in 3 randomized study days beginning at 1600h: 1) no exercise (NoEx), 2) moderate exercise (ModEx; 55%VO2max) and 3) high intensity interval exercise (IntEx; 4 min (80%VO2max)/3 min (50% VO2max). Frequent blood samples were analyzed for glucose and lactate (whole-blood), and insulin, c-peptide, glucagon, and irisin (plasma) throughout 190 min of testing. Results Plasma irisin increased above baseline during ModEx and IntEx (P0.05). Peak irisin levels during ModEx and IntEx exercise were 11.9± 3.4% and 12.3 ± 4.1% relative to baseline (Pexercise intensities (P>0.05). Irisin levels remained elevated above resting for 125 minutes post-exercise during ModEx, whereas levels returned to baseline within 15 minutes post-exercise during IntEx. Similarly, no associations were found between plasma irisin levels and circulating lactate, glucose, insulin, c-peptide, or glucagon among study days (P>0.05). However, there was an inverse association between basal irisin and lean mass (r = -0.70, P = 0.01). Conclusion A single bout of moderate and high intensity afternoon exercise induces modest increases in circulating irisin concentrations during exercise; however the regulation post-exercise appears to be dimorphic between exercise intensity in obese females. Future studies are needed to compare morning and afternoon exercise on irisin secretion. PMID:28125733

  14. Beetroot Juice Supplementation Improves High-Intensity Intermittent Type Exercise Performance in Trained Soccer Players

    Directory of Open Access Journals (Sweden)

    Jean Nyakayiru

    2017-03-01

    Full Text Available It has been shown that nitrate supplementation can enhance endurance exercise performance. Recent work suggests that nitrate ingestion can also increase intermittent type exercise performance in recreational athletes. We hypothesized that six days of nitrate supplementation can improve high-intensity intermittent type exercise performance in trained soccer players. Thirty-two male soccer players (age: 23 ± 1 years, height: 181 ± 1 m, weight: 77 ± 1 kg, playing experience: 15.2 ± 0.5 years, playing in the first team of a 2nd or 3rd Dutch amateur league club participated in this randomized, double-blind cross-over study. All subjects participated in two test days in which high-intensity intermittent running performance was assessed using the Yo-Yo IR1 test. Subjects ingested nitrate-rich (140 mL; ~800 mg nitrate/day; BR or a nitrate-depleted beetroot juice (PLA for six subsequent days, with at least eight days of wash-out between trials. The distance covered during the Yo-Yo IR1 was the primary outcome measure, while heart rate (HR was measured continuously throughout the test, and a single blood and saliva sample were collected just prior to the test. Six days of BR ingestion increased plasma and salivary nitrate and nitrite concentrations in comparison to PLA (p < 0.001, and enhanced Yo-Yo IR1 test performance by 3.4 ± 1.3% (from 1574 ± 47 to 1623 ± 48 m; p = 0.027. Mean HR was lower in the BR (172 ± 2 vs. PLA trial (175 ± 2; p = 0.014. Six days of BR ingestion effectively improves high-intensity intermittent type exercise performance in trained soccer players.

  15. Increased high-intensity activity in elite Australian football finals matches.

    Science.gov (United States)

    Aughey, Robert J

    2011-09-01

    Australian football (AF) is a highly intermittent sport, requiring athletes to accelerate hundreds of times with repeated bouts of high-intensity running (HIR). Players aim to be in peak physical condition for finals, with anecdotal evidence of increased speed and pressure of these games. However, no data exists on the running demands of finals games, and therefore the aim of this study was to compare the running demands of finals to regular season games with matched players and opponents. Player movement was recorded by GPS at 5 Hz and expressed per period of the match (rotation), for total distance, high-intensity running (HIR, 4.17-10.00 m·s-1) and maximal accelerations (2.78-10.00 m·s-2). All data was compared for regular season and finals games and the magnitude of effects was analyzed with the effect size (ES) statistic and expressed with confidence intervals. Each of the total distance (11%; ES: 0.78 ± 0.30), high-intensity running distance (9%; ES: 0.29 ± 0.25) and number of maximal accelerations (97%; ES: 1.30 ± 0.20) increased in finals games. The largest percentage increases in maximal accelerations occurred from a commencement velocity of between 3-4 (47%; ES: 0.56 ± 0.21) and 4-5 m·s-1 (51%; ES: 0.72 ± 0.26), and with players nearly double the number of maximal accelerations in finals compared with regular season games. This large increase is superimposed on requirements to cover a greater total distance and spend more time at high velocity during finals games. Players can be effectively conditioned to cope with these increased demands, even during a long competitive season.

  16. Effects of high-intensity interval training on the VO2 response during severe exercise.

    Science.gov (United States)

    Duffield, Rob; Edge, Johann; Bishop, David

    2006-06-01

    This study examined the effect of high-intensity interval training on the VO2 response during severe, constant-load exercise. Prior to, and following training, 10 females (V O2 peak 37.4+/-6.0 mL kg-1 min-1) performed a graded exercise test to determine VO2 peak and lactate threshold (LT) and a 6 min cycle test (CT) at the pre-training VO2 peak intensity. Training involved high-intensity intervals (2 min work, 1 min rest) performed 3x week for 8 weeks. Breath-by-breath data from 0 to 6 min during the CT were smoothed using 5s averages and fit to a bi-exponential model starting from 20s. Training resulted in significant improvements in VO2 max (2.34+/-0.37-2.78+/-0.30 L min-1), power at VO2 max (170+/-26-204+/-25 W) and power at LT (113+/-17-136+/-20 W) (pVO2 response showed a significant increase in the amplitude of the primary phase (A1) (1396+/-103-1695+/-100 mL min-1; pVO2 (VO2 EE), with no difference (p>0.05) in the time constants of either phase or the amplitude of the slow component (318+/-67-380+/-48 mL; p=0.15). In conjunction, accumulated oxygen deficit (AOD) (43.7+/-9.8-17.2+/-2.8 mL O2 eq kg-1) and anaerobic contribution to the CT (19.4+/-4.4-7.2+/-1.2%) were significantly reduced. In contrast to previous moderate-intensity research, a high-intensity interval training program increased A1 and VO2 EE for the same absolute exercise intensity, decreasing the AOD during a severe-intensity CT.

  17. Effects of high-intensity swimming training on the bones of ovariectomized rats

    Science.gov (United States)

    Oh, Taewoong; Tanaka, Sakura; Naka, Tatsuki; Igawa, Shoji

    2016-01-01

    [Purpose] This study was performed to assess the effects of high-intensity intermittent swimming training(HIT) on bone in ovariectomized rats. [Methods] Six-week-old female Sprague-Dawley rats were randomly assigned to either sham operation or bilateral ovariectomy. After surgery, they were divided into the following four groups: 1) sham-operated sedentary (S), 2) sham-operated exercise training (SE), 3) OVX sedentary (O), 4) OVX exercise training (OE) 5) OVX given 17β-estradiol (OE2) and 6) OVX exercise training and given 17β-estradiol (OEE). SE, OE and OEE rats were used extremely high-intensity swim exercise. The rats repeated fourteen 20-s swimming bouts with a weight equivalent to 14, 15, and 16% of body weight for the first 5, the next 9, and the last 5 days, respectively. Between exercise bouts, a 10-s pause was allowed. HIT was originally designed as an exercise method; a method that very quickly induces an increase in the maximum oxygen intake (Tabata I et al., 1996). OEE and OE2 rats were subcutaneously injected ethanol with 25μg/kg body weight 17β-estradiol 3 times per week. [Results] Bone strength, bone mineral density and trabecular bone parameters were measured after a 8-weeks experimental period. Bone strength was significantly higher in the SE, OE, OE2 and OEE group compared with the O group. BV/TV was significant increase in the SE, OE groups compared with the O group. BMD showed no difference in the OE group compared with the O group. [Conclusion] This study demonstrate some beneficial effects of postmenopausal osteoporosis of high-intensity intermittent swimming training on bone structure and strength. PMID:27757386

  18. RELATIONSHIP BETWEEN BLOOD LACTATE AND HYPERVENTILATION DURING HIGH-INTENSITY CONSTANT-LOAD EXERCISE IN HEAT

    Directory of Open Access Journals (Sweden)

    T. Chiba

    2011-09-01

    Full Text Available The purpose of this study was to examine the relationship between hyperventilation and increase in blood lactate during high-intensity constant-load exercise in heat and normal conditions. Seven male volunteers exercised for 10 min on a cycle ergometer at 80%·VO2max in heat (40ºC, 50%relative humidity: HT and normal conditions (20ºC, 50% relative humidity: CON. Oxygen uptake, carbon dioxide output, ventilation, blood lactate and blood electrolytes (K , Na , Cl− were measured in HT and CON. We found that ventilation was significantly higher during exercise in HT compared with CON (p<0.05 and RER tends to be higher in HT than in CON. Blood lactate was significantly higher at 3 min during exercise in HT compared with CON (5.96 ± 0.57 mEq·l-1 5.00 ± 0.28 mEq·l-1, p<0.05. Change in strong ion difference [∆SID = (∆K ∆Na − (∆Cl− ∆La−], which affects ∆HCO3− in blood significantly, was lower at 5 min during exercise in HT compared with in CON (p<0.05. These results suggest that hyperventilation during exercise in heat would induce lower HCO3− in blood and consequently would result in an increase in blood lactate at an earlier time during high-intensity exercise in heat. It was concluded that hyperventilation during short-term high-intensity exercise in heat is temporarily associated with an increase in blood lactate.

  19. Enhancing gas-phase reaction in a plasma using high intensity and high power ultrasonic acoustic waves

    DEFF Research Database (Denmark)

    2010-01-01

    is absorbed into said plasma (104), and where a sound pressure level of said generated ultrasonic high intensity and high power acoustic waves (102) is at least substantially 140 dB and where an acoustic power of said generated ultrasonic high intensity and high power acoustic waves (102); is at least......This invention relates to enhancing a gas-phase reaction in a plasma comprising: creating plasma (104) by at least one plasma source (106), and wherein that the method further comprises: generating ultrasonic high intensity and high power acoustic waves (102) having a predetermined amount...... of acoustic energy by at least one ultrasonic high intensity and high power gas-jet acoustic wave generator (101), where said ultrasonic high intensity and high power acoustic waves are directed to propagate towards said plasma (104) so that at least a part of said predetermined amount of acoustic energy...

  20. Design and construction of a reverberation chamber for high-intensity acoustic testing.

    Science.gov (United States)

    Slusser, R. A.

    1973-01-01

    A high-intensity acoustic test facility was constructed at the Jet Propulsion Laboratory (JPL) to support the Mariner Mars 1971 project. For ease of construction, the reverberation chamber itself is rectangular, which resulted in very little sacrifice in acoustic performance. Levels as high as 156 dB can be achieved with the chamber empty and test levels of 150 dB have been used with a Mariner Mars spacecraft model (full size) in the chamber. Levels as high as this must be generated using electropneumatic transducers, which modulate gaseous nitrogen to this facility.

  1. New initiatives on lepton flavor violation and neutrino oscillation with high intense muon and neutrino sources

    CERN Document Server

    Kuno, Yoshitaka; Pakvasa, Sandip

    2002-01-01

    The area of physics involving muons and neutrinos has become exciting in particle physics. Using their high intensity sources, physicists undertake, in various ways, extensive searches for new physics beyond the Standard Model, such as tests of supersymmetric grand unification (SUSY-GUT) and precision measurements of the muon and neutrino properties, which will in future extend to ambitious studies such as determination of the three-generation neutrino mixing matrix elements and CP violation in the lepton sector. The physics of this field is advancing, with potential improvements of the source

  2. Development of a cryogenic hydrogen microjet for high-intensity, high-repetition rate experiments

    Science.gov (United States)

    Kim, J. B.; Göde, S.; Glenzer, S. H.

    2016-11-01

    The advent of high-intensity, high-repetition-rate lasers has led to the need for replenishing targets of interest for high energy density sciences. We describe the design and characterization of a cryogenic microjet source, which can deliver a continuous stream of liquid hydrogen with a diameter of a few microns. The jet has been imaged at 1 μm resolution by shadowgraphy with a short pulse laser. The pointing stability has been measured at well below a mrad, for a stable free-standing filament of solid-density hydrogen.

  3. Reactor target from metal chromium for "pure" high-intensive artificial neutrino source

    Science.gov (United States)

    Gavrin, V. N.; Kozlova, Yu. P.; Veretenkin, E. P.; Logachev, A. V.; Logacheva, A. I.; Lednev, I. S.; Okunkova, A. A.

    2017-01-01

    The paper presents the first results of development of manufacturing technology of metallic chromium targets from highly enriched isotope 50Cr for irradiation in a high flux nuclear reactor to obtain a compact high intensity neutrino source with low content of radionuclide impurities and minimum losses of enriched isotope. The main technological stages are the hydrolysis of chromyl fluoride, the electrochemical reduction of metallic chromium, the hot isostatic pressing of chromium powder and the electrical discharge machining of chromium bars. The technological stages of hot isostatic pressing of chromium powder and of electrical discharge machining of Cr rods have been tested.

  4. HIGH INTENSITY FOCUSED ULTRASOUND FOR TREATMENT UNRESECTABLE MALIGNANT TUMORS IN 75 PATIENTS

    Institute of Scientific and Technical Information of China (English)

    郑国强

    2004-01-01

    Objective: To study preliminary experience of high intensity focused ultrasound (HIFU) for unresectable malignant tumors in 75 patients. Methods: The clinical data of 75 patients with unresectable tumor was analyzed retrospectively. Results: Among 75 patients, ten out of 57 cases achieved good local control in short-term, 5 patients liver tumor, 4 patients with tumor in the chest wall and one patient with bone matestics. Seven patients had skin burn and 2 patients developed intestinal perforations. Conclusion: HIFU is a novel tool for local tumor treatment. HIFU treatment for patients with unresectable tumor in the chest wall is effective.

  5. Effects and Sustainability of a 13-Day High-Intensity Shock Microcycle in Soccer

    Directory of Open Access Journals (Sweden)

    Patrick Wahl

    2014-06-01

    Full Text Available The preseason in soccer is a short period of 6-8 weeks where conditional abilities, technical and tactical elements need to be trained. Therefore, time is lacking to perform long term preparation periods for different abilities, especially endurance training. There is evidence that the implementation of high-intensity shock microcycles in preseason training could be one way to improve physical performance in a short period of time. Therefore, the purpose of the present study was to examine the effects and the sustainability of a high-intensity shock microcycle on soccer specific performance. Over 2 weeks, 12 male soccer players (26.1 ± 4.5 years performed 12 high-intensity training (HIT sessions in addition to their usual training. Before (pre, 6 days (6d and 25 days (25d after training, subjects performed Counter Movement Jump (CMJ, Repeated-Sprint Ability (RSA test and Yo-Yo Intermittent Recovery Test Level 2 (YYIR2. Mean sprint time (RSAMean (cohen’s d = -1.15, percentage decrement score (RSAIndex (cohen’s d = -1.99 and YYIR2 (cohen’s d = +1.92 improved significantly from pre to 6d. 25d after, values showed a significant reduction for YYIR2 (cohen’s d = -0.81 and small to moderate but not significant increase for RSAMean (cohen’s d = +0.37 and RSAIndex (cohen’s d = +0.7 compared to 6d values. Small but no significant increases were found for CMJ (cohen’s d = +0.33 and no significant and substantial changes were found for RSABest (cohen’s d = -0.07 from pre to 6d. For competitive soccer players, block periodization of HIT offers a promising way to largely improve RSA and YYIR2 in a short period of time. Despite moderate to large decreases in RSAIndex and YYIR2 performance in the 19 day period without HIT, values still remained significantly higher 25d after the last HIT session compared to pre-values. However, it might be necessary to include isolated high-intensity sessions after a HIT training block in order to maintain the

  6. Th.P-19. Collisional effects and dynamic aperture in high-intensity storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Benedetti, C. [Dipartimento di Fisica Universita di Bologna and INFN, Via Irnerio 46, Bologna 40126 (Italy)]. E-mail: benedetti@bo.infn.it; Rambaldi, S. [Dipartimento di Fisica Universita di Bologna and INFN, Via Irnerio 46, Bologna 40126 (Italy); Turchetti, G. [Dipartimento di Fisica Universita di Bologna and INFN, Via Irnerio 46, Bologna 40126 (Italy)

    2005-05-21

    We analyze the dynamic aperture in the presence of strong sextupolar errors for a high-intensity beam. The scaling laws for the short-term dynamic aperture are examined and its dependence on the perveance is discussed in a mean field approximation for a coasting beam. The collisional effects of Coulombian interaction are estimated for a linear lattice using a scaling law for the relaxation time. The collisional effects on the long-time dynamic aperture are discussed by comparing the results of full Hamiltonian integration with a mean field theory. An application to a storage ring with the HIDIF parameters is briefly outlined.

  7. A focusable, convergent fast-electron beam from ultra-high-intensity laser-solid interactions

    CERN Document Server

    Scott, R H H

    2015-01-01

    A novel scheme for the creation of a convergent, or focussing, fast-electron beam generated from ultra-high-intensity laser-solid interactions is described. Self-consistent particle-in-cell simulations are used to demonstrate the efficacy of this scheme in two dimensions. It is shown that a beam of fast-electrons of energy 500 keV - 3 MeV propagates within a solid-density plasma, focussing at depth. The depth of focus of the fast-electron beam is controlled via the target dimensions and focussing optics.

  8. Vacuum Outgassing Behavior of Carbon Nanotube Cathode with High-Intensity Pulsed Electron Emission

    Science.gov (United States)

    Shen, Yi; Zhang, Huang; Xia, Liansheng; Liu, Xingguang; Pan, Haifeng; Lv, Lu; Yang, Anmin; Shi, Jinshui; Zhang, Linwen; Deng, Jianjun

    2015-02-01

    Experimental investigations on the vacuum outgassing of a carbon nanotube (CNT) cathode with high-intensity pulsed electron emission on a 2 MeV linear induction accelerator injector are presented. Under the 1.60 MV diode voltage, the CNT cathode could provide 1.67 kA electron beam with the amount of outgassing of about 0.51 Pa·L. It is found that the amount of outgassing, which determines the cathode emission current, depends on the diode voltage and the vacuum.

  9. Impact of high intensity exercise on muscle morphology in EAE rats

    DEFF Research Database (Denmark)

    Wens, I; Dalgas, U; Verboven, K

    2015-01-01

    The impact of high-intensity exercise on disease progression and muscle contractile properties in experimental autoimmune encephalomyelitis (EAE) remains unclear. Control (CON) and EAE rats were divided into sedentary and exercise groups. Before onset (experiment 1, n=40) and after hindquarter...... paralysis (experiment 2, n=40), isokinetic foot extensor strength, cross sectional area (CSA) of tibialis anterior (TA), extensor digitorum longus (EDL) and soleus (SOL) and brain-derived neurotrophic factor (BDNF) levels were assessed. EAE reduced muscle fiber CSA of TA, EDL and SOL. In general, exercise...

  10. Analysis of a high intensity shear zone between overlapping fiber ends in a polymer matrix composite

    DEFF Research Database (Denmark)

    Lindgreen, Britta

    2008-01-01

    The formation of high intensity shear zones in a glass fiber reinforced thermoplast is studied numerically. The thermoplast is characterized by a finite strain elastic-viscoplastic constitutive relation and the calculations are carried out using a dynamic finite element program where plane strain...... conditions are assumed to prevail in the direction of the thickness. Different ratios of the elongation strain and the transverse strain are studied to consider the effect of different levels of stress triaxiality and the effect of these states on the shear zone development and emerging strain and stress...

  11. High-Intensity Training Improves Exercise Performance in Elite Women Volleyball Players During a Competitive Season.

    Science.gov (United States)

    Purkhús, Elisabeth; Krustrup, Peter; Mohr, Magni

    2016-11-01

    Purkhús, E, Krustrup, P, and Mohr, M. High-intensity training improves exercise performance in elite women volleyball players during a competitive season. J Strength Cond Res 30(11): 3066-3072, 2016-Elite women volleyball players (n = 25; mean ± SD: age, 19 ± 5 years; height, 171 ± 7 cm; weight, 63 ± 10 kg) volunteered to participate in the study. They were randomized into a high-intensity training (HIT; n = 13) group and a control (CON; n = 12) group. In addition to the normal team training and games, HIT performed 6-10 × 30-seconds all-out running intervals separated by 3-minute recovery periods 3 times per week during a 4-week in-season period whereas CON only completed the team training sessions and games. Preintervention and postintervention, all players completed the arrowhead agility test (AAT), a repeated sprint test (RST; 5 × 30 meters separated by 25 seconds of recovery), and the Yo-Yo Intermittent Recovery level 2 test (Yo-Yo IR2) followed by a-10 minute rest period and the Yo-Yo IR1 test. Mean running distance during HIT in week 1 was 152 ± 4 m and increased (p ≤ 0.05) by 4.6% (159 ± 3 m) in week 4. The AAT performance improved (p ≤ 0.05) by 2.3% (18.87 ± 0.97-18.44 ± 1.06 seconds) and RST by 4.3% postintervention in the HIT group only. Baseline RST fatigue index was 7.0 ± 2.9 and 6.2 ± 5.0% in HIT and CON, respectively, but was lowered (p ≤ 0.05) to 2.7 ± 3.0% posttraining in HIT and remained unaltered in CON (5.5 ± 5.0%). In HIT, Yo-Yo IR2 and Yo-Yo IR1 performance improved by 12.6 and 18.3% postintervention, respectively, with greater (p ≤ 0.05) Yo-yo IR1 change scores than in CON. In conclusion, additional high-intensity in-season training performed as interval running improved agility, repeated sprint ability, and high-intensity intermittent exercise performance in elite women volleyball players.

  12. High intensity compact Compton X-ray sources: Challenges and potential of applications

    Energy Technology Data Exchange (ETDEWEB)

    Jacquet, M., E-mail: mjacquet@lal.in2p3.fr

    2014-07-15

    Thanks to the exceptional development of high power femtosecond lasers in the last 15 years, Compton based X-ray sources are in full development over the world in the recent years. Compact Compton sources are able to combine the compactness of the instrument with a beam of high intensity, high quality, tunable in energy. In various fields of applications such as biomedical science, cultural heritage preservation and material science researches, these sources should provide an easy working environment and the methods currently used at synchrotrons could be largely developed in a lab-size environment as hospitals, labs, or museums.

  13. Start-to-end simulations for the proposed Fermilab high intensity proton source

    Energy Technology Data Exchange (ETDEWEB)

    Carneiro, Jean-Paul; Johnson, D.E.; Webber, R.C.; /Fermilab

    2007-06-01

    A High Intensity Proton Source consisting in an 8 GeV superconducting H-minus linac and transfer line to the Main Injector has been proposed. The primary mission is to increase the intensity of the Fermilab Main Injector for the production of neutrino superbeams. Start-to-end simulations from the RFQ to the stripping foil using the simulation code TRACK (ANL) is presented in this paper. In particular, we will study the impact of jitter errors on the H-minus phase space at the stripping foil.

  14. Ultrasound imaging and evaluation of lesion induced by High Intensity Focused Ultrasound

    Institute of Scientific and Technical Information of China (English)

    ZHONG Hui; WAN Mingxi; JIANG Yifeng; WANG Supin

    2006-01-01

    The present study was to investigate the differential imaging method for detecting HIFU (High Intensity Focused Ultrasound)-induced lesions and the estimation of variation of attenuation for lesion evaluation with log spectral difference algorithm. Experiment results of bovine muscle and liver in vitro were acquired. Several algorithms for lesion detection - Absolute Difference (AD), Sum Absolute Differences (SAD) and Sum Squared Differences (SSD) - were analyzed with several window sizes and threshold values. Then three attenuation parameters were compared to evaluate the degree of tissue damage. It was found that variation of the mean attenuation △(α) was an effective parameter to evaluate lesions.

  15. Using high intensity ultrasound as a tool to change the functional properties of interesterified soybean oil.

    Science.gov (United States)

    Ye, Yubin; Wagh, Ashwini; Martini, Silvana

    2011-10-12

    High intensity ultrasound (HIU) was used to change the crystallization behavior, generate small crystals, and improve the texture of a low saturated shortening (interesterified soybean oil). Samples were crystallized at different temperatures (26, 28, 30, and 32 °C) without and with the application of HIU. Different acoustic power levels (110, 72, 61, 54, and 44 W) were used. Results show that higher acoustic powers had a greater effect on crystal size reduction, induced crystallization, and generated harder, more elastic and viscous materials. These effects were more significant when HIU was applied in the presence of crystals and when the sample was crystallized at 32 °C.

  16. Enhancement of antitumor vaccine in ablated hepatocellular carcinoma by high-intensity focused ultrasound

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    AIM:To investigate whether tumor debris created by high-intensity focused ultrasound(HIFU)could trigger antitumor immunity in a mouse hepatocellular carcinoma model. METHODS:Twenty C57BL/6J mice bearing H22 hepatocellular carcinoma were used to generate antitumor vaccines.Ten mice underwent HIFU ablation,and the remaining 10 mice received a sham-HIFU procedure with no ultrasound irradiation.Sixty normal mice were randomly divided into HIFU vaccine,tumor vaccine and control groups.These mice were immunized w...

  17. Salutary effects of high-intensity interval training in persons with elevated cardiovascular risk.

    Science.gov (United States)

    Fleg, Jerome L

    2016-01-01

    Although moderate-intensity continuous training (MICT) has been the traditional model for aerobic exercise training for over four decades, a growing body of literature has demonstrated equal if not greater improvement in aerobic capacity and similar beneficial effects on body composition, glucose metabolism, blood pressure, and quality of life from high-intensity interval training (HIIT). An advantage of HIIT over MICT is the shorter time required to perform the same amount of energy expenditure. The current brief review summarizes the effects of HIIT on peak aerobic capacity and cardiovascular risk factors in healthy adults and those with various cardiovascular diseases, including coronary artery disease, chronic heart failure, and post heart transplantation.

  18. Stimulated recombination of antiproton and positron with ultra-short ultra-high intensity laser pulse

    CERN Document Server

    Ryabinina, M V

    2003-01-01

    Ionization of hydrogen atom in the field of high-intense ultra-short femto-second laser pulse recently became the subject of comprehensive theoretical approaches. On the other hand, there exists experimental evidence that short electric pulses can effectively stimulate electron-proton (as well as antiproton-positron) recombination to high-level (Rydberg) state. In this paper we present the results of the theoretical estimations of antiproton-positron recombination cross-section in cold mixed plasmas in traps in the conditions of ATHENA/ATRAP experiments in CERN under the action of sub-fs laser pulse with TW intensity. (2 refs).

  19. A large aperture reflective wave-plate for high-intensity short-pulse laser experiments

    CERN Document Server

    Aurand, Bastian; Zhao, Huanyu; Kuschel, Stephan; Wünsche, Martin; Jäckel, Oliver; Heyer, Martin; Wunderlich, Frank; Kaluza, Malte C; Paulus, Gerhard G; Kuehl, Thomas

    2012-01-01

    We report on a reflective wave-plate system utilizing phase-shifting mirrors (PSM) for a continuous variation of elliptical polarization without changing the beam position and direction. The scalability of multilayer optics to large apertures and the suitability for high-intensity broad-bandwidth laser beams make reflective wave-plates an ideal tool for experiments on relativistic laser-plasma interaction. Our measurements confirm the preservation of the pulse duration and spectrum when a 30-fs Ti:Sapphire laser beam passes the system.

  20. High-intensity intermittent exercise attenuates ad-libitum energy intake.

    Science.gov (United States)

    Sim, A Y; Wallman, K E; Fairchild, T J; Guelfi, K J

    2014-03-01

    To examine the acute effects of high-intensity intermittent exercise (HIIE) on energy intake, perceptions of appetite and appetite-related hormones in sedentary, overweight men. Seventeen overweight men (body mass index: 27.7±1.6 kg m(-2); body mass: 89.8±10.1 kg; body fat: 30.0±4.3%; VO(2peak): 39.2±4.8 ml kg(-1) min(-1)) completed four 30-min experimental conditions using a randomised counterbalanced design. CON: resting control, MC: continuous moderate-intensity exercise (60% VO(2peak)), HI: high-intensity intermittent exercise (alternating 60 s at 100% VO(2peak) and 240 s at 50% VO(2peak)), VHI: very-high-intensity intermittent exercise (alternating 15 s at 170% VO(2peak) and 60 s at 32% VO(2peak)). Participants consumed a standard caloric meal following exercise/CON and an ad-libitum meal 70 min later. Capillary blood was sampled and perceived appetite assessed at regular time intervals throughout the session. Free-living energy intake and physical activity levels for the experimental day and the day after were also assessed. Ad-libitum energy intake was lower after HI and VHI compared with CON (P=0.038 and P=0.004, respectively), and VHI was also lower than MC (P=0.028). Free-living energy intake in the subsequent 38 h remained less after VHI compared with CON and MC (P≤0.050). These observations were associated with lower active ghrelin (P≤0.050), higher blood lactate (P≤0.014) and higher blood glucose (P≤0.020) after VHI compared with all other trials. Despite higher heart rate and ratings of perceived exertion (RPE) during HI and VHI compared with MC (P≤0.004), ratings of physical activity enjoyment were similar between all the exercise trials (P=0.593). No differences were found in perceived appetite between trials. High-intensity intermittent exercise suppresses subsequent ad-libitum energy intake in overweight inactive men. This format of exercise was found to be well tolerated in an overweight population.

  1. Evaluate thermal lesion using Nakagami imaging for monitoring of high-intensity focused ultrasound

    Science.gov (United States)

    Zhang, Siyuan; Li, Chong; Zhou, Fanyu; Wang, Supin; Wan, Mingxi

    2017-03-01

    High-intensity focused ultrasound (HIFU) is currently being developed as a noninvasive technique for the treatment of cancer located in various tissues. Cavitation microbubbles (MBs) have been potential to aid treatment while the acoustic posterior shadowing effects of MBs influence the accuracy for defining the location and range of ablated thermal lesions during focused ultrasound surgery when using ultrasonic monitoring imaging. This work explored the feasibility of using ultrasonic Nakagami imaging to evaluate the ablated region induced by focused ultrasound exposures at different acoustic power levels in transparent tissue-mimicking phantoms.

  2. Design concept of radiation control system for the high intensity proton accelerator facility

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, Yukihiro; Ikeno, Koichi; Akiyama, Shigenori; Harada, Yasunori [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2002-11-01

    Description is given for the characteristic radiation environment for the High Intensity Proton Accelerator Facility and the design concept of the radiation control system of it. The facility is a large scale accelerator complex consisting of high energy proton accelerators carrying the highest beam intensity in the world and the related experimental facilities and therefore provides various issues relevant to the radiation environment. The present report describes the specifications for the radiation control system for the facility, determined in consideration of these characteristics. (author)

  3. The effect of high-intensity intermittent exercise on body composition of overweight young males.

    Science.gov (United States)

    Heydari, M; Freund, J; Boutcher, S H

    2012-01-01

    To determine the effect of a 12-week high intensity intermittent exercise (HIIE) intervention on total body, abdominal, trunk, visceral fat mass, and fat free mass of young overweight males. Participants were randomly assigned to either exercise or control group. The intervention group received HIIE three times per week, 20 min per session, for 12 weeks. Aerobic power improved significantly (P 0.05) occurred in levels of insulin, HOMA-IR, and blood lipids. Twelve weeks of HIIE resulted in significant reductions in total, abdominal, trunk, and visceral fat and significant increases in fat free mass and aerobic power.

  4. Measurement for titanium density distribution on Ti:sapphire rods for high intensity pump source

    Energy Technology Data Exchange (ETDEWEB)

    Usami, Tsutomu; Nishimura, Akihiko; Sugiyama, Akira [Japan Atomic Energy Research Inst., Kizu, Kyoto (Japan). Kansai Research Establishment

    2001-10-01

    A Ti:sapphire rod of 190 mm length made by Czochralski (CZ) technique was used in the flashlamp pumped high intensity laser for Yb:glass chirped pulse amplification. In the absorption spectroscopy of the rod immersed in an index matching liquid of methylene iodide, heterogeneous Ti{sup 3+} density distribution was measured along the direction of length. It has been first clarified that the Ti:sapphire rod grown by the CZ technique has 20% difference of the Ti{sup 3+} density at the both ends. (author)

  5. High-intensity interval training (HIIT for patients with chronic diseases

    Directory of Open Access Journals (Sweden)

    Leanna M. Ross

    2016-06-01

    Full Text Available Exercise training provides physiological benefits for both improving athletic performance and maintaining good health. Different exercise training modalities and strategies exist. Two common exercise strategies are high-intensity interval training (HIIT and moderate-intensity continuous exercise training (MCT. HIIT was first used early in the 20th century and popularized later that century for improving performance of Olympic athletes. The primary premise underlying HIIT is that, compared to energy expenditure-matched MCT, a greater amount of work is performed at a higher intensity during a single exercise session which is achieved by alternating high-intensity exercise intervals with low-intensity exercise or rest intervals. Emerging research suggests that this same training method can provide beneficial effects for patients with a chronic disease and should be included in the comprehensive medical management plan. Accordingly, a major consideration in developing an individual exercise prescription for a patient with a chronic disease is the selection of an appropriate exercise strategy. In order to maximize exercise training benefits, this strategy should be tailored to the individual's need. The focus of this paper is to provide a brief summary of the current literature regarding the use of HIIT to enhance the functional capacity of individuals with cardiovascular, pulmonary, and diabetes diseases.

  6. Dissimilar Physiological and Perceptual Responses Between Sprint Interval Training and High-Intensity Interval Training.

    Science.gov (United States)

    Wood, Kimberly M; Olive, Brittany; LaValle, Kaylyn; Thompson, Heather; Greer, Kevin; Astorino, Todd A

    2016-01-01

    High-intensity interval training (HIIT) and sprint interval training (SIT) elicit similar cardiovascular and metabolic adaptations vs. endurance training. No study, however, has investigated acute physiological changes during HIIT vs. SIT. This study compared acute changes in heart rate (HR), blood lactate concentration (BLa), oxygen uptake (VO2), affect, and rating of perceived exertion (RPE) during HIIT and SIT. Active adults (4 women and 8 men, age = 24.2 ± 6.2 years) initially performed a VO2max test to determine workload for both sessions on the cycle ergometer, whose order was randomized. Sprint interval training consisted of 8 bouts of 30 seconds of all-out cycling at 130% of maximum Watts (Wmax). High-intensity interval training consisted of eight 60-second bouts at 85% Wmax. Heart rate, VO2, BLa, affect, and RPE were continuously assessed throughout exercise. Repeated-measures analysis of variance revealed a significant difference between HIIT and SIT for VO2 (p HIIT (209.3 ± 40.3 kcal) vs. SIT (193.5 ± 39.6 kcal). During HIIT, subjects burned significantly more calories and reported lower perceived exertion than SIT. The higher VO2 and lower BLa in HIIT vs. SIT reflected dissimilar metabolic perturbation between regimens, which may elicit unique long-term adaptations. If an individual is seeking to burn slightly more calories, maintain a higher oxygen uptake, and perceive less exertion during exercise, HIIT is the recommended routine.

  7. The Effects of High Intensity Interval Training vs Steady State Training on Aerobic and Anaerobic Capacity

    Science.gov (United States)

    Foster, Carl; Farland, Courtney V.; Guidotti, Flavia; Harbin, Michelle; Roberts, Brianna; Schuette, Jeff; Tuuri, Andrew; Doberstein, Scott T.; Porcari, John P.

    2015-01-01

    High intensity interval training (HIIT) has become an increasingly popular form of exercise due to its potentially large effects on exercise capacity and small time requirement. This study compared the effects of two HIIT protocols vs steady-state training on aerobic and anaerobic capacity following 8-weeks of training. Fifty-five untrained college-aged subjects were randomly assigned to three training groups (3x weekly). Steady-state (n = 19) exercised (cycle ergometer) 20 minutes at 90% of ventilatory threshold (VT). Tabata (n = 21) completed eight intervals of 20s at 170% VO2max/10s rest. Meyer (n = 15) completed 13 sets of 30s (20 min) @ 100% PVO2 max/ 60s recovery, average PO = 90% VT. Each subject did 24 training sessions during 8 weeks. Results: There were significant (p HIIT protocols are time efficient, they are not superior to conventional exercise training in sedentary young adults. Key points Steady state training equivalent to HIIT in untrained students Mild interval training presents very similar physiologic challenge compared to steady state training HIIT (particularly very high intensity variants were less enjoyable than steady state or mild interval training Enjoyment of training decreases across the course of an 8 week experimental training program PMID:26664271

  8. High-intensity interval training prevents oxidant-mediated diaphragm muscle weakness in hypertensive mice.

    Science.gov (United States)

    Bowen, T Scott; Eisenkolb, Sophia; Drobner, Juliane; Fischer, Tina; Werner, Sarah; Linke, Axel; Mangner, Norman; Schuler, Gerhard; Adams, Volker

    2017-01-01

    Hypertension is a key risk factor for heart failure, with the latter characterized by diaphragm muscle weakness that is mediated in part by increased oxidative stress. In the present study, we used a deoxycorticosterone acetate (DOCA)-salt mouse model to determine whether hypertension could independently induce diaphragm dysfunction and further investigated the effects of high-intensity interval training (HIIT). Sham-treated (n = 11), DOCA-salt-treated (n = 11), and DOCA-salt+HIIT-treated (n = 15) mice were studied over 4 wk. Diaphragm contractile function, protein expression, enzyme activity, and fiber cross-sectional area and type were subsequently determined. Elevated blood pressure confirmed hypertension in DOCA-salt mice independent of HIIT (P HIIT. Myosin heavy chain (MyHC) protein expression tended to decrease (∼30%; P = 0.06) in DOCA-salt vs. sham- and DOCA-salt+HIIT mice, whereas oxidative stress increased (P HIIT further prevented direct oxidant-mediated diaphragm contractile dysfunction (P HIIT.-Bowen, T. S., Eisenkolb, S., Drobner, J., Fischer, T., Werner, S., Linke, A., Mangner, N., Schuler, G., Adams, V. High-intensity interval training prevents oxidant-mediated diaphragm muscle weakness in hypertensive mice.

  9. Highly intense monocycle terahertz vortex generation by utilizing a Tsurupica spiral phase plate

    Science.gov (United States)

    Miyamoto, Katsuhiko; Kang, Bong Joo; Kim, Won Tae; Sasaki, Yuta; Niinomi, Hiromasa; Suizu, Koji; Rotermund, Fabian; Omatsu, Takashige

    2016-12-01

    Optical vortex, possessing an annular intensity profile and an orbital angular momentum (characterized by an integer termed a topological charge) associated with a helical wavefront, has attracted great attention for diverse applications due to its unique properties. In particular for terahertz (THz) frequency range, several approaches for THz vortex generation, including molded phase plates consisting of metal slit antennas, achromatic polarization elements and binary-diffractive optical elements, have been recently proposed, however, they are typically designed for a specific frequency. Here, we demonstrate highly intense broadband monocycle vortex generation near 0.6 THz by utilizing a polymeric Tsurupica spiral phase plate in combination with tilted-pulse-front optical rectification in a prism-cut LiNbO3 crystal. A maximum peak power of 2.3 MW was obtained for THz vortex output with an expected topological charge of 1.15. Furthermore, we applied the highly intense THz vortex beam for studying unique nonlinear behaviors in bilayer graphene towards the development of nonlinear super-resolution THz microscopy and imaging system.

  10. High-intensity exercise training for the prevention of type 2 diabetes mellitus.

    Science.gov (United States)

    Rynders, Corey A; Weltman, Arthur

    2014-02-01

    Aerobic exercise training and diet are recommended for the primary prevention of type 2 diabetes mellitus and cardiovascular disease. The American Diabetes Association (ADA) recommends that adults with prediabetes engage in ≥ 150 minutes per week of moderate activity and target a 7% weight loss. However, traditional moderate-intensity (MI) exercise training programs are often difficult to sustain for prediabetic adults; a commonly cited barrier to physical activity in this population is the "lack of time" to exercise. When matched for total energy expenditure, high-intensity (HI) exercise training has a lower overall time commitment compared with traditional low-intensity (LI) or MI exercise training. Several recent studies comparing HI exercise training with LI and MI exercise training reported that HI exercise training improves skeletal muscle metabolic control and cardiovascular function in a comparable and/or superior way relative to LI and MI exercise training. Although patients can accrue all exercise benefits by performing LI or MI activities such as walking, HI activities represent a time-efficient alternative to meeting physical activity guidelines. High-intensity exercise training is a potent tool for improving cardiometabolic risk for prediabetic patients with limited time and may be prescribed when appropriate.

  11. High-intensity resistance training attenuates dexamethasone-induced muscle atrophy.

    Science.gov (United States)

    Krug, André L O; Macedo, Anderson G; Zago, Anderson S; Rush, James W E; Santos, Carlos F; Amaral, Sandra L

    2016-05-01

    In this study we investigated the effects of high-intensity resistance training (RT) on dexamethasone (DEX)-induced muscle atrophy in flexor hallucis longus (FHL), tibialis anterior (TA), and soleus (SOL) muscles. Rats underwent either high-intensity RT or were kept sedentary. In the last 10 days they received either DEX (0.5 mg/kg/day, intraperitoneally) or saline. DEX reduced body weight (-21%), food intake (-28%), FHL and TA muscle mass (-20% and -18%, respectively), and increased muscle-specific ring finger 1 (MuRF-1) protein level (+37% and +45.5%). RT attenuated FHL muscle atrophy through a combination of low increase in MuRF-1 protein level (-3.5%) and significant increases in mammalian target of rapamycin (mTOR) (+63%) and p70S6K (+46% and +49% for control and DEX, respectively) protein levels. RT attenuated DEX-induced muscle atrophy through a combination of increases in mTOR and p70S6K protein levels and a low increase in MuRF-1 protein level. © 2016 Wiley Periodicals, Inc.

  12. High-intensity endurance training improves adiponectin mRNA and plasma concentrations.

    Science.gov (United States)

    Moghadasi, Mehrzad; Mohebbi, Hamid; Rahmani-Nia, Farhad; Hassan-Nia, Sadegh; Noroozi, Hamid; Pirooznia, Nazanin

    2012-04-01

    Adiponectin is an anti-inflammatory protein that reduced in obesity. Exercise training may reduce the adipose tissue (AT), although it is not well known whether exercise-induced change in AT, increases the adiponectin mRNA expression and plasma concentrations or not; therefore, the purpose of this study was to investigate the adiponectin mRNA and plasma concentrations in middle-aged men after 12 weeks high-intensity exercise training and after a week detraining. Sixteen sedentary overweight and obese middle-aged men (age 41.18 ± 6.1 years; ± SD) volunteered to participate in this study. The subjects were randomly assigned to training group (n = 8) or control group (n = 8). The training group performed endurance training 4 days a week for 12 weeks at an intensity corresponding to 75-80% individual maximum oxygen consumption for 45 min. After 12 weeks of training, subjects underwent a week of detraining. The results showed that the BMI as well as central and peripheral AT volume were decreased in the training group compared to the control group (P training group resulted in a significant increase (P training compared to the control group (P training group. In conclusion, high-intensity endurance training caused an increase adiponectin mRNA in obese middle-aged men.

  13. The Effects of High Intensity Interval Training vs Steady State Training on Aerobic and Anaerobic Capacity.

    Science.gov (United States)

    Foster, Carl; Farland, Courtney V; Guidotti, Flavia; Harbin, Michelle; Roberts, Brianna; Schuette, Jeff; Tuuri, Andrew; Doberstein, Scott T; Porcari, John P

    2015-12-01

    High intensity interval training (HIIT) has become an increasingly popular form of exercise due to its potentially large effects on exercise capacity and small time requirement. This study compared the effects of two HIIT protocols vs steady-state training on aerobic and anaerobic capacity following 8-weeks of training. Fifty-five untrained college-aged subjects were randomly assigned to three training groups (3x weekly). Steady-state (n = 19) exercised (cycle ergometer) 20 minutes at 90% of ventilatory threshold (VT). Tabata (n = 21) completed eight intervals of 20s at 170% VO2max/10s rest. Meyer (n = 15) completed 13 sets of 30s (20 min) @ 100% PVO2 max/ 60s recovery, average PO = 90% VT. Each subject did 24 training sessions during 8 weeks. There were significant (p training group, as well as significant increases in peak (+8, + 9 and +5%) & mean (+4, +7 and +6%) power during Wingate testing, but no significant differences between groups. Measures of the enjoyment of the training program indicated that the Tabata protocol was significantly less enjoyable (p training in sedentary young adults. Key pointsSteady state training equivalent to HIIT in untrained studentsMild interval training presents very similar physiologic challenge compared to steady state trainingHIIT (particularly very high intensity variants were less enjoyable than steady state or mild interval trainingEnjoyment of training decreases across the course of an 8 week experimental training program.

  14. Can Trained Runners Effectively Attenuate Impact Acceleration During Repeated High-Intensity Running Bouts?

    Science.gov (United States)

    Clansey, Adam C; Lake, Mark J; Wallace, Eric S; Feehally, Tom; Hanlon, Michael

    2016-06-01

    The purpose of this study was to investigate the effects of prolonged high-intensity running on impact accelerations in trained runners. Thirteen male distance runners completed two 20-minute treadmill runs at speeds corresponding to 95% of onset of blood lactate accumulation. Leg and head accelerations were collected for 20 s every fourth minute. Rating of perceived exertion (RPE) scores were recorded during the third and last minute of each run. RPE responses increased (P run to the end (17.7 ± 1.5, very hard) of the second run. Runners maintained their leg impact acceleration, impact attenuation, stride length, and stride frequency characteristics with prolonged run duration. However, a small (0.11-0.14g) but significant increase (P < .001) in head impact accelerations were observed at the end of both first and second runs. It was concluded that trained runners are able to control leg impact accelerations during sustained high-intensity running. Alongside the substantial increases in perceived exertion levels, running mechanics and frequency domain impact attenuation levels remained constant. This suggests that the present trained runners are able to cope from a mechanical perspective despite an increased physiological demand.

  15. REPORT OF THE SNOWMASS M6 WORKING GROUP ON HIGH INTENSITY PROTON SOURCES.

    Energy Technology Data Exchange (ETDEWEB)

    CHOU,W.; WEI,J.

    2001-08-14

    The M6 working group had more than 40 active participants (listed in Section 4). During the three weeks at Snowmass, there were about 50 presentations, covering a wide range of topics associated with high intensity proton sources. The talks are listed in Section 5. This group also had joint sessions with a number of other working groups, including E1 (Neutrino Factories and Muon Colliders), E5 (Fixed-Target Experiments), M1 (Muon Based Systems), T4 (Particle Sources), T5 (Beam dynamics), T7 (High Performance Computing) and T9 (Diagnostics). The M6 group performed a survey of the beam parameters of existing and proposed high intensity proton sources, in particular, of the proton drivers. The results are listed in Table 1. These parameters are compared with the requirements of high-energy physics users of secondary beams in Working Groups E1 and E5. According to the consensus reached in the E1 and E5 groups, the U.S. HEP program requires an intense proton source, a 1-4 MW Proton Driver, by the end of this decade.

  16. Report of the Snowmass M6 Working Group on high intensity proton sources

    Energy Technology Data Exchange (ETDEWEB)

    Weiren Chou and J. Wei

    2002-08-20

    The U.S. high-energy physics program needs an intense proton source, a 1-4 MW Proton Driver (PD), by the end of this decade. This machine will serve as a stand-alone facility that will provide neutrino superbeams and other high intensity secondary beams such as kaons, muons, neutrons, and anti-protons (cf. E1 and E5 group reports) and also serve as the first stage of a neutrino factory (cf. M1 group report). It can also be a high brightness source for a VLHC. Based on present accelerator technology and project construction experience, it is both feasible and cost-effective to construct a 1-4 MW Proton Driver. Two recent PD design studies have been made, one at FNAL and the other at the BNL. Both designed PD's for 1 MW proton beams at a cost of about U.S. $200M (excluding contingency and overhead) and both designs were upgradeable to 4 MW. An international collaboration between FNAL, BNL and KEK on high intensity proton facilities is addressing a number of key design issues. The superconducting (sc) RF cavities, cryogenics, and RF controls developed for the SNS can be directly adopted to save R&D efforts, cost, and schedule. PD studies are also actively being pursued at Europe and Japan.

  17. Matched and equipartitioned design method for modern high-intensity radio frequency quadrupole accelerators

    Science.gov (United States)

    Yan, X. Q.; Jameson, R. A.; Lu, Y. R.; Guo, Z. Y.; Fang, J. X.; Chen, J. E.

    2007-07-01

    A new design method—Matched and equipartitioned (EP) design method—has been proposed for radio frequency quadrupole (RFQ) dynamics design, on the considerations of preventing emittance growth and halo formation in high-intensity linacs by means of keeping beam envelope matched and energy balance within the beam, as well as avoiding structure resonances [R.A. Jameson, IEEE Trans. Nucl. Sci. NS-28 (1981) 2408; R.A. Jameson et al., Scaling and optimization in high-intensity linear accelerators, LA-CP-91-272, Los Alamos National Laboratory, July 1991 (introduction of LINACS design code); R.A. Jameson, AIP Conf. Proc. 279 (1992) 969; R.A. Jameson, An approach to fundamental study of beam loss minimization, in: Y.K. Batygin (Ed.), AIP Conference Proceedings, vol. 480, Space Charge Dominated Beam Physics for Heavy Ion Fusion, Saitama, Japan, December 1998]. As there are more than three parameters for a linear accelerator, but only three equations (two envelope equations and an EP equation) are available to design the structural parameters of the RFQ accelerator around the beam, therefore the others have to be determined by additional rules. Following these equations and rules, a new RFQ design code named MATCHDESIGN has been written at Peking University. Three example designs are generated by this code and their simulation results have been compared with a conventional RFQ, which had proved the feasibilities and merits of the new method.

  18. Effectiveness of High Intensity Laser Therapy for Reduction of Pain in Knee Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Anna Angelova

    2016-01-01

    Full Text Available Introduction. Osteoarthritis is the most common type of arthritis. It is the main cause of chronic musculoskeletal pain and disability among the elderly population. Aim. This is a pilot, randomized clinical study about the effect of high intensity laser therapy in patients with osteoarthritis of the knee (OA of the knee. Material and Method. 72 patients (aged between 39 and 83 years with (clinically and radiographically proved OA of the knee were included in the study. They were randomized in two groups: therapeutic (test one (n=37, 65,11 ± 1,40 (mean ± SD years old; patients were treated with HILT and control group (n=35, 64,71 ± 1,98; patients receive sham laser. Both groups had seven sessions of treatment. VAS and dolorimetry were used for assessment of pain before and after the therapy. Pedobarometric analysis (static and dynamic was used to assess comparatively the contact surface area and maximum pressure under the heel. Results. Pain levels measured by VAS and dolorimetry decreased significantly in the therapeutic group after seven days of treatment (p< 0,001. Conclusion. The results after seven days of treatment show more intensive and cumulative effect after the application of high intensity laser therapy in comparison to sham laser. This is the reason why HILT can be a method of choice in the treatment of gonarthrosis.

  19. Controlled generation of high-intensity optical rogue waves by induced modulation instability.

    Science.gov (United States)

    Zhao, Saili; Yang, Hua; Chen, Nengsong; Zhao, Chujun

    2017-01-04

    Optical rogue waves are featured as the generation of high amplitude events at low probability in optical systems. Moreover, the formation of optical rogue waves is unpredictable and transient in photonic crystal fibers. In this paper, we put forward a method to generate high-intensity optical rogue waves in a more controlled way based on induced modulation instability, which can suppress the noise effect and hence play a leading role in the process of pulse evolution. Our numerical simulations indicate that the generation of rogue wave can be controlled when seeding at the optimal modulation frequency and the intensity of rogue wave can be enhanced with appropriate modulation depth. Further, high-intensity rogue wave can also be ejected in the fiber with a shorter propagation length by regulating the modulation depth. These results all provide a better understanding of optical rogue wave, which can contribute to the generation of tunable long-wavelength spectral components and selective excitation of mid-infrared supercontinuum.

  20. Amino acid supplements and recovery from high-intensity resistance training.

    Science.gov (United States)

    Sharp, Carwyn P M; Pearson, David R

    2010-04-01

    The purpose of this study was to investigate whether short-term amino acid supplementation could maintain a short-term net anabolic hormonal profile and decrease muscle cell damage during a period of high-intensity resistance training (overreaching), thereby enhancing recovery and decreasing the risk of injury and illness. Eight previously resistance trained males were randomly assigned to either a high branched chain amino acids (BCAA) or placebo group. Subjects consumed the supplement for 3 weeks before commencing a fourth week of supplementation with concomitant high-intensity total-body resistance training (overreaching) (3 x 6-8 repetitions maximum, 8 exercises). Blood was drawn prior to and after supplementation, then again after 2 and 4 days of training. Serum was analyzed for testosterone, cortisol, and creatine kinase. Serum testosterone levels were significantly higher (p creatine kinase levels were significantly lower (p resistance training. These findings suggest that short-term amino acid supplementation, which is high in BCAA, may produce a net anabolic hormonal profile while attenuating training-induced increases in muscle tissue damage. Athletes' nutrient intake, which periodically increases amino acid intake to reflect the increased need for recovery during periods of overreaching, may increase subsequent competitive performance while decreasing the risk of injury or illness.

  1. The Effect of High Intensity Intermittent Exercise on Power Output for the Upper Body

    Directory of Open Access Journals (Sweden)

    Leonie Harvey

    2015-06-01

    Full Text Available The aim of the present study was to examine and measure high intensity, intermittent upper body performance, in addition to identifying areas of the body that affect the variance in total work done during the 5 × 6 s sprint test. Fifteen males completed an upper body 5 × 6 s sprint test on a modified electro-magnetically braked cycle ergometer, which consisted of five maximal effort sprints, each 6 s in duration, separated by 24 s of passive recovery. A fly wheel braking force corresponding to 5% of the participants’ body weight was used as the implemented resistance level. Body composition was measured using dual-energy X-ray absorptiometry (DEXA. Percent (% decrement was calculated as 100 − (Total work/ideal work × 100. Significant (P < 0.05 differences were found between sprints for both absolute and relative (W, W·kg−1, W·kg−1 Lean body mass (LBM and W·kg−1 Upper body lean body mass (UBLBM peak (PP and mean (MP power. The % decrement in total work done over the five sprints was 11.4%. Stepwise multiple linear regression analysis revealed that UBLBM accounts for 87% of the variance in total work done during the upper body 5 × 6 s sprint test. These results provide a descriptive analysis of upper body, high intensity intermittent exercise, demonstrating that PP and MP output decreased significantly during the upper body 5 × 6 s sprint test.

  2. Effect of high-intensity hypoxic training on sea-level swimming performances.

    Science.gov (United States)

    Truijens, M J; Toussaint, H M; Dow, J; Levine, B D

    2003-02-01

    The objective of this study was to test the hypothesis that high-intensity hypoxic training improves sea-level performances more than equivalent training in normoxia. Sixteen well-trained collegiate and Masters swimmers (10 women, 6 men) completed a 5-wk training program, consisting of three high-intensity training sessions in a flume and supplemental low- or moderate-intensity sessions in a pool each week. Subjects were matched for gender, performance level, and training history, and they were assigned to either hypoxic [Hypo; inspired O2 fraction (Fi(O(2))) = 15.3%, equivalent to a simulated altitude of 2,500 m] or normoxic (Norm; Fi(O(2)) = 20.9%) interval training in a randomized, double-blind, placebo-controlled design. All pool training occurred under Norm conditions. The primary performance measures were 100- and 400-m freestyle time trials. Laboratory outcomes included maximal O(2) uptake (Vo(2 max)), anaerobic capacity (accumulated O(2) deficit), and swimming economy. Significant (P = 0.02 and swimming performances and Vo(2 max) in well-trained swimmers, with no additive effect of hypoxic training.

  3. Aerobic Fitness for Young Athletes: Combining Game-based and High-intensity Interval Training.

    Science.gov (United States)

    Harrison, C B; Kinugasa, T; Gill, N; Kilding, A E

    2015-11-01

    This study compared the effect of game-based training (GT) vs. a mix of game-based training and high-intensity interval training (MT) on physical performance characteristics. 26 young athletes (13.9±0.3 years) were assigned to either GT (n=13) or MT (n=13) for 6 weeks. Game-based training consisted of 2×8-11 min 3 vs. 3 'bucketball' SSGs separated by 3 min of passive rest twice per week, while MT consisted of one SSGs session and one high-intensity session of 15 s runs at 90-95% of the speed reached at the end of the 30-15 intermittent fitness test (VIFT) interspersed with 15 s passive recovery. Peak oxygen uptake (V˙ O2peak), VIFT, jump height, and speed were assessed pre- and post-training. Following training, V˙ O2peak (5.5±3.3%; ES=large) improved after MT, whereas VIFT improved after MT (6.6±3.2%; ES, large) and GT (4.2±5.5%, ES=small). 5-m sprint improved after GT (ES=small), while 20 m sprint and jump height were unchanged. In conclusion, while MT and GT were both effective at increasing performance parameters, greater effects were seen following MT. Therefore, MT should be considered as the preferred training method for improving aerobic power in young athletes.

  4. High-intensity interval training has positive effects on performance in ice hockey players.

    Science.gov (United States)

    Naimo, M A; de Souza, E O; Wilson, J M; Carpenter, A L; Gilchrist, P; Lowery, R P; Averbuch, B; White, T M; Joy, J

    2015-01-01

    In spite of the well-known benefits that have been shown, few studies have looked at the practical applications of high-intensity interval training (HIIT) on athletic performance. This study investigated the effects of a HIIT program compared to traditional continuous endurance exercise training. 24 hockey players were randomly assigned to either a continuous or high-intensity interval group during a 4-week training program. The interval group (IG) was involved in a periodized HIIT program. The continuous group (CG) performed moderate intensity cycling for 45-60 min at an intensity that was 65% of their calculated heart rate reserve. Body composition, muscle thickness, anaerobic power, and on-ice measures were assessed pre- and post-training. Muscle thickness was significantly greater in IG (p=0.01) when compared to CG. The IG had greater values for both ∆ peak power (p<0.003) and ∆ mean power (p<0.02). Additionally, IG demonstrated a faster ∆ sprint (p<0.02) and a trend (p=0.08) for faster ∆ endurance test time to completion for IG. These results indicate that hockey players may utilize short-term HIIT to elicit positive effects in muscle thickness, power and on-ice performance.

  5. Pacing, the missing piece of the puzzle to high-intensity interval training.

    Science.gov (United States)

    Zadow, E K; Gordon, N; Abbiss, C R; Peiffer, J J

    2015-03-01

    This study examined physiological and perceptual responses to matched work high-intensity interval training using all-out and 2 even-paced methodologies. 15 trained male cyclists performed 3 interval sessions of three 3-min efforts with 3 min of active recovery between efforts. The initial interval session was completed using all-out pacing, with the following 2 sessions being completed with computer- and athlete-controlled pacing in a randomised and semi-counterbalanced manner. Computer- and athlete-controlled intervals were completed at the mean power from the corresponding interval during the all-out trial. Oxygen consumption and ratings of perceived exertion were recorded during each effort. 20 min following each session, participants completed a 4-km time trial and provided sessional rating of perceived exertion. Oxygen consumption was greater during all-out (54.1±6.6 ml.kg(-1).min(-1); pintervals. Distribution of pace throughout high-intensity interval training can influence perceptual and metabolic stress along with subsequent performance and should be considered during the prescription of such training.

  6. Recovering limonite from Australia iron ores by flocculation-high intensity magnetic separation

    Institute of Scientific and Technical Information of China (English)

    LUO Li-qun; ZHANG Jing-sheng; YU Yong-fu

    2005-01-01

    Successful recovery of limonite from iron fines was achieved by using flocculation-high intensity magnetic separation (FIMS) and adding hydrolyzed and causticized flocculants according to the characteristic of iron fines. The separation results of the three iron samples are as follows: iron grade 66.77%-67.98% and the recovery of iron 69.26%-70.70% by the FIMS process with flocculants. The comparative results show that under the same separation conditions the FIMS process can effectively increase the recovery of iron by 10.97%-15.73%. The flowsheet results confirm the reliability of the process in a SHP high intensity magnetic separator. The concentrate product can be used as raw materials for direct reduction iron-smelting. The hydrolyzed and causticized flocculants can selectively flocculate fine feebly-magnetic iron mineral particles to increase their apparent separation sizes. The larger the separation size, the stronger the magnetic force. By comparing the separation results of the three samples it is found that among the three samples the higher the limonite content, the better the separation result. This means that the separation result relates closely to the flocculation process and the adding pattern of the flocculant.

  7. Heart rate variability during high-intensity field exercise in female distance runners.

    Science.gov (United States)

    Sumi, K; Suzuki, S; Matsubara, M; Ando, Y; Kobayashi, F

    2006-10-01

    The purposes of this study were to demonstrate the transition of heart rate variability (HRV) during trials in the field and to examine the relationship between peak frequency of high-frequency band (HF) and stride frequency. Ten healthy long-distance college female runners (age 19-21 years) performed a 3000 m realistic time trial. The time-series power spectrum analysis by maximum entropy method was used to evaluate cardiac autonomic nervous activity during the race. Cross-correlation coefficients were calculated to estimate the degree of linear co-ordination between the central peak frequency of HF and stride frequency. Just after starting, the decrease in HF (0.15-1.00 Hz) and a transient increase of low-frequency band (LF)/HF were found. After that, the HF remained at a low level and LF/HF decreased sharply. These findings suggested that the parasympathetic activity was suppressed and sympathetic activity increased just after starting, and the sympathetic activity reached the saturated level according to continuation of high-intensity exercise. In spite of the significant decrease of HRV during trials, peak frequency of HF could be differentiated clearly. The cross-correlation coefficient of peak frequency of HF and stride frequency was from 0.703 to 0.868. This finding indicated that exercise rhythm reflected HRV during high-intensity running in the field.

  8. A MOTIVATIONAL MUSIC AND VIDEO INTERVENTION IMPROVES HIGH-INTENSITY EXERCISE PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Martin J. Barwood

    2009-09-01

    Full Text Available Music and video are utilised by recreational gym users to enhance their exercise experience. Music and video have not been investigated for their combined ergogenic effect during high intensity exercise. To induce fatigue, this study was performed in warm (~26°C, moist conditions (~50%RH. Six, non-acclimated, male participants took part in the study. Each participant completed three 30-minute exercise bouts on a motorised treadmill under three counterbalanced conditions on separate days: control (CON, motivational music plus video intervention (M, non-motivational intervention (NM. They completed a warm-up (5 km·h-1 [5 minutes], 9km·h-1 [10 minutes] followed by a maximal effort run (15 minutes. Participants did not receive any feedback of time elapsed, distance run or speed. Measures: Distance covered (metres, heart rate, blood lactate accumulation (Blac and ratings of perceived exertion (RPE. Participants in the M condition ran significantly further than in the NM (M: 3524 [388]metres; NM: 3110 [561]metres; CON: 3273 [458]metres and CON conditions, accumulated more Blac, but did not increase their peak RPE rating (p < 0.05. The M intervention improved tolerance of high intensity exercise in warm conditions. It was proposed that a change in attentional processing from internal (physical sensations to external perspective (music and video may have facilitated this improvement. These findings have strong implications for improving health, fitness and engagement in gym-based exercise programs

  9. Experimental analysis of 1-3 piezocomposites for high-intensity focused ultrasound transducer applications.

    Science.gov (United States)

    Chen, Gin-Shin; Liu, Hsin-Chih; Lin, Yu-Cheng; Lin, Yu-Li

    2013-01-01

    Piezocomposites with 1-3 connectivity have been extensively used in medical imaging transducers and high-intensity focused ultrasound transducers, but most studies of 1-3 piezocomposites address medical imaging applications. The purpose of this study was to completely investigate 1-3 composites specifically for high-power ultrasonic transducer applications via a series of experimental analyses. PZT4-epoxy composite focused transducers with various aspect ratios and volume fractions were constructed in-house for the evaluation of the coupling factor, dielectric loss tangent, quality factor, bandwidth, acoustic impedance, and electroacoustic efficiency. The experimental analyses demonstrated that although the coupling factor of composite transducers was higher than that of the ceramic transducer, the composite transducers had a lower efficiency due to the high dielectric loss and high mechanical energy loss of the composites. In addition, the bandwidth and acoustic impedance of composite transducers were superior to the ceramic transducer. For the composite transducers, the efficiency and acoustic impedance were inversely proportional to the aspect ratio and linearly proportional to the volume fraction. The coupling of inter pillars that are too close to each other could cause a significant decrease in the efficiency of the composite transducer. With an appropriate design in terms of the aspect ratio, volume fraction, and PZT-pillar spacing, a high-efficiency composite high-intensity focused ultrasound transducer can be achieved.

  10. Study of Atomization of a Water Jet by High-Intensity Aerial Ultrasonic Waves

    Science.gov (United States)

    Ito, Youichi

    2001-05-01

    An experimental study has been carried out on the atomization of a water jet by aerially radiating it with high-intensity ultrasonic waves. A sound source that enables the linear generation of high-intensity aerial ultrasonic waves (frequency: approximately 20 kHz) is combined with a cylindrical reflection plate in order to create a standing-wave sound field. An attempt has been made to atomize a water jet of 1 mm diameter by passing it through the above sound field at a velocity of approximately 30 m/s. It has been clarified that nodes of sound pressure in the standing-wave sound field are effective for the atomization of a water jet. In addition, the atomizing phenomenon of a water jet has been observed precisely. The relation between the intensity of sound waves required for atomization and the radiation duration has also been clarified. Even the radiation of sound waves for only 2 ms atomizes water. This suggests that a very fast water jet at 300-500 m/s might be atomized.

  11. Influence of carbohydrate supplementation on plasma cytokine and neutrophil degranulation responses to high intensity intermittent exercise.

    Science.gov (United States)

    Bishop, Nicolette C; Gleeson, Michael; Nicholas, Ceri W; Ali, Ajmol

    2002-06-01

    Ingesting carbohydrate (CHO) beverages during prolonged, continuous heavy exercise results in smaller changes in the plasma concentrations of several cytokines and attenuates a decline in neutrophil function. In contrast, ingesting CHO during prolonged intermittent exercise appears to have negligible influence on these responses, probably due to the overall moderate intensity of these intermittent exercise protocols. Therefore, we examine the effect of CHO ingestion on plasma interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) and lipopolysaccharide (LPS)-stimulated neutrophil degranulation responses to high-intensity intermittent running. Six trained male soccer players performed 2 exercise trials, 7 days apart, in a randomized, counterbalanced design. On each occasion, they completed six 15-min periods of intermittent running consisting of maximal sprinting interspersed with less intense periods of running and walking. Subjects consumed either CHO or artificially sweetened placebo (PLA) beverages immediately before and at 15-min intervals during the exercise. At 30 min post-exercise, CHO versus PLA was associated with a higher plasma glucose concentration (p exercise, LPS-stimulated elastase release per neutrophil fell 31% below baseline values on the PLA trial (p = .06) compared with 17% on the CHO trial (p = .30). Plasma TNF-alpha concentration increased following the exercise (main effect of time, p attenuates changes in plasma IL-6 concentration, neutrophil trafficking, and LPS-stimulated neutrophil degranulation in response to intermittent exercise that involves bouts of very high intensity exercise.

  12. Halo Coupling and Cleaning by a Space Charge Resonance in High Intensity Beams

    CERN Document Server

    Hofmann, Ingo

    2013-01-01

    We show that the difference resonance driven by the space charge pseudo-octupole of high-intensity beams not only couples the beam core emittances; it can also lead to emittance exchange in the beam halo, which is of relevance for beam loss in high intensity accelerators. With reference to linear accelerators the "main resonance" kz/kxy =1 (corresponding to the Montague resonance 2Qx-2Qy=0 in circular accelerators) may lead to such a coupling and transfer of halo between planes. Coupling of transverse halo into the longitudinal plane - or vice versa - can occur even if the core (rms) emittances are exactly or nearly equal. This halo argument justifies additional caution in linac design including consideration of avoiding an equipartitioned design. At the same time, however, this mechanism may also qualify as active dynamical halo cleaning scheme by coupling a halo from the longitudinal plane into the transverse plane, where local scraping is accessible. We present semi-analytical emittance coupling rates and ...

  13. High-intensity focused ultrasound for thyroid nodule ablation: the evidence to date

    Directory of Open Access Journals (Sweden)

    Kovatcheva RD

    2017-01-01

    Full Text Available Roussanka D Kovatcheva,1 Katja Zaletel,2 1Department of Thyroid and Metabolic Bone Disorders, Clinical Center of Endocrinology, Medical University, Sofia, Bulgaria; 2Department of Nuclear Medicine, University Medical Centre Ljubljana, Ljubljana, Slovenia Abstract: Thyroid nodules are common in occurrence and most of them are benign in nature. Some of these nodules are to be treated as they continue to grow or cause undesirable symptoms. Recently, several minimally invasive thermal ablation techniques have been introduced to overcome the complications of traditional methods such as surgery. High-intensity focused ultrasound (HIFU is the latest advance in treatment modalities, which is a noninvasive procedure that permits localized target destruction without affecting the surrounding tissues. HIFU is currently used in the treatment of various solid malignant and benign tumors. The purpose of this review is to provide an introduction to the literature, principles, and advances of HIFU therapy of benign thyroid nodules, as well as to provide a discussion on its efficacy, complications, and future. Keywords: thyroid nodule, high-intensity focused ultrasound, ultrasound guidance, ablation techniques

  14. High-intensity interval training (HIIT) for patients with chronic diseases

    Institute of Scientific and Technical Information of China (English)

    Leanna M. Ross; Ryan R. Porter; J. Larry Durstine

    2016-01-01

    Exercise training provides physiological benefits for both improving athletic performance and maintaining good health. Different exercise training modalities and strategies exist. Two common exercise strategies are high-intensity interval training (HIIT) and moderate-intensity continuous exercise training (MCT). HIIT was first used early in the 20th century and popularized later that century for improving performance of Olympic athletes. The primary premise underlying HIIT is that, compared to energy expenditure-matched MCT, a greater amount of work is performed at a higher intensity during a single exercise session which is achieved by alternating high-intensity exercise intervals with low-intensity exercise or rest intervals. Emerging research suggests that this same training method can provide beneficial effects for patients with a chronic disease and should be included in the comprehensive medical management plan. Accordingly, a major consideration in developing an individual exercise prescription for a patient with a chronic disease is the selection of an appropriate exercise strategy. In order to maximize exercise training benefits, this strategy should be tailored to the individual’s need. The focus of this paper is to provide a brief summary of the current literature regarding the use of HIIT to enhance the functional capacity of individuals with cardiovascular, pulmonary, and diabetes diseases.

  15. Energy gain and spectral tailoring of ion beams using ultra-high intensity laser beams

    Science.gov (United States)

    Prasad, Rajendra; Swantusch, Marco; Cerchez, Mirela; Spickermann, Sven; Auorand, Bastian; Wowra, Thomas; Boeker, Juergen; Willi, Oswald

    2015-11-01

    The field of laser driven ion acceleration over the past decade has produced a huge amount of research. Nowadays, several multi-beam facilities with high rep rate system, e.g. ELI, are being developed across the world for different kinds of experiments. The study of interaction dynamics of multiple beams possessing ultra-high intensity and ultra-short pulse duration is of vital importance. Here, we present the first experimental results on ion acceleration using two ultra-high intensity beams. Thanks to the unique capability of Arcturus laser at HHU Düsseldorf, two almost identical, independent beams in laser parameters such as intensity (>1020 W/cm2), pulse duration (30 fs) and contrast (>1010), could be accessed. Both beams are focused onto a 5 μm thin Ti target. While ensuring spatial overlap of the two beams, at relative temporal delay of ~ 50 ps (optimum delay), the proton and carbon ion energies were enhanced by factor of 1.5. Moreover, strong modulation in C4+ions near the high energy cut-off is observed later than the optimum delay for the proton enhancement. This offers controlled tailoring of the spectral content of heavy ions.

  16. Accelerator technical design report for high-intensity proton accelerator facility project, J-PARC

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-03-01

    This report presents the detail of the technical design of the accelerators for the High-Intensity Proton Accelerator Facility Project, J-PARC. The accelerator complex comprises a 400-MeV room-temperature linac (600-MeV superconducting linac), 3-GeV rapid-cycling synchrotron (RCS), and a 50-GeV synchrotron (MR). The 400-MeV beam is injected to the RCS, being accelerated to 3 GEV. The 1-MW beam thus produced is guided to the Materials Life Science Experimental Facility, with both the pulsed spallation neutron source and muon source. A part of the beam is transported to the MR, which provides the 0.75-MW beam to either the Nuclear and Fundamental Particle Experimental Facility or the Neutrino Production Target. On the other hand, the beam accelerated to 600 MeV by the superconducting linac is used for the Nuclear Waster Transmutation Experiment. In this way, this facility is unique, being multipurpose one, including many new inventions and Research and Development Results. This report is based upon the accomplishments made by the Accelerator Group and others of the Project Team, which is organized on the basis of the Agreement between JAERI and KEK on the Construction and Research and Development of the High-Intensity Proton Accelerator Facility. (author)

  17. SU-E-J-04: Integration of Interstitial High Intensity Therapeutic Ultrasound Applicators On a Clinical MRI-Guided High Intensity Focused Ultrasound Treatment Planning Software Platform

    Energy Technology Data Exchange (ETDEWEB)

    Ellens, N [Johns Hopkins University, Baltimore, Maryland (United States); Partanen, A [Philips Healthcare, Andover, Massachusetts (United States); Ghoshal, G; Burdette, E [Acoustic MedSystems Inc., Savoy, IL (United States); Farahani, K [National Cancer Institute, Bethesda, MD (United States)

    2015-06-15

    Purpose: Interstitial high intensity therapeutic ultrasound (HITU) applicators can be used to ablate tissue percutaneously, allowing for minimally-invasive treatment without ionizing radiation [1,2]. The purpose of this study was to evaluate the feasibility and usability of combining multielement interstitial HITU applicators with a clinical magnetic resonance imaging (MRI)-guided focused ultrasound software platform. Methods: The Sonalleve software platform (Philips Healthcare, Vantaa, Finland) combines anatomical MRI for target selection and multi-planar MRI thermometry to provide real-time temperature information. The MRI-compatible interstitial US applicators (Acoustic MedSystems, Savoy, IL, USA) had 1–4 cylindrical US elements, each 1 cm long with either 180° or 360° of active surface. Each applicator (4 Fr diameter, enclosed within a 13 Fr flexible catheter) was inserted into a tissue-mimicking agar-silica phantom. Degassed water was circulated around the transducers for cooling and coupling. Based on the location of the applicator, a virtual transducer overlay was added to the software to assist targeting and to allow automatic thermometry slice placement. The phantom was sonicated at 7 MHz for 5 minutes with 6–8 W of acoustic power for each element. MR thermometry data were collected during and after sonication. Results: Preliminary testing indicated that the applicator location could be identified in the planning images and the transducer locations predicted within 1 mm accuracy using the overlay. Ablation zones (thermal dose ≥ 240 CEM43) for 2 active, adjacent US elements ranged from 18 mm × 24 mm (width × length) to 25 mm × 25 mm for the 6 W and 8 W sonications, respectively. Conclusion: The combination of interstitial HITU applicators and this software platform holds promise for novel approaches in minimally-invasive MRI-guided therapy, especially when bony structures or air-filled cavities may preclude extracorporeal HIFU.[1] Diederich et al

  18. A preliminary study on the changes in some potential markers of muscle-cell degradation in sub-maximally exercised horses supplemented with a protein and amino acid mixture.

    Science.gov (United States)

    van den Hoven, R; Bauer, A; Hackl, S; Zickl, M; Spona, J; Zentek, J

    2011-10-01

    In this preliminary study, time-dependent changes in plasma CK and AST activity, tyrosine (Tyr), 3-methyl-histidine (3mHis), glucose and lactate concentrations were analysed in nine horses under two different conditions. Furthermore, intramuscular concentrations of Tyr, 3mHis and activities of cathepsin B, acid phosphatase (ACP), glucose-6-phosphate dehydrogenase (G6PDH) and mRNA expression of ubiquitin were determined at the same time. After studying the effects of exercise alone, the effects of exercise and feeding of an experimental protein/amino acid (AA) supplement were analysed. Horses were submitted to a total of four standardised exercise tests (SETs) of high intensity. Potential markers of muscle break down were determined prior to, immediately after, 4 and 18 h after exercise. The experiment was subdivided into two consecutive periods of 3 weeks. In each period, two SETs were performed. In the second period, horses were fed with the protein/AA supplement within 1 h after exercise. Significant changes in plasma, intramuscular Tyr levels and mRNA expression of ubiquitin were caused both by time in relation to exercise and by treatment with the protein/AA supplement. The experimental supplement significantly decreased the 4-h post-exercise expression of ubiquitin mRNA in muscle. Only a borderline increase of markers of lysosomal involvement was seen and CK and AST activity generally showed their normal post-exercise patterns. A clear post-exercise reduction of this CK activity, however, was not observed after supplementation with the protein/AA mixture. The current findings indicate that horses might benefit from protein and AA supplementation directly after training by decreasing post-exercise proteolysis. The results support that further studies should be performed to characterize changes in equine protein metabolism caused by exercise including underlying molecular mechanisms.

  19. Effects of anabolic steroids and high-intensity aerobic exercise on skeletal muscle of transgenic mice.

    Directory of Open Access Journals (Sweden)

    Karina Fontana

    Full Text Available In an attempt to shorten recovery time and improve performance, strength and endurance athletes occasionally turn to the illicit use of anabolic-androgenic steroids (AAS. This study evaluated the effects of AAS treatment on the muscle mass and phenotypic characteristics of transgenic mice subjected to a high-intensity, aerobic training program (5d/wk for 6 weeks. The transgenic mice (CETP(+/-LDLr(-/+ were engineered to exhibit a lipid profile closer to humans. Animals were divided into groups of sedentary (Sed and/or training (Ex mice (each treated orally with AAS or gum arabic/vehicle: Sed-C, Sed-M, ex-C, ex-M. The effects of AAS (mesterolone: M on specific phenotypic adaptations (muscle wet weight, cross-sectional area, and fiber type composition in three hindlimb muscles (soleus:SOL, tibialis anterior:TA and gastrocnemius:GAS were assessed. In order to detect subtle changes in fiber type profile, the entire range of fiber types (I, IC, IIAC, IIA, IIAD, IID, IIDB, IIB was delineated using mATPase histochemistry. Body weight gain occurred throughout the study for all groups. However, the body weight gain was significantly minimized with exercise. This effect was blunted with mesterolone treatment. Both AAS treatment (Sed-M and high-intensity, aerobic training (ex-C increased the wet weights of all three muscles and induced differential hypertrophy of pure and hybrid fibers. Combination of AAS and training (ex-M resulted in enhanced hypertrophy. In the SOL, mesterolone treatment (Sed-M and ex-M caused dramatic increases in the percentages of fiber types IC, IIAC, IIAD, IID, with concomitant decrease in IIA, but had minimal impact on fiber type percentages in the predominantly fast muscles. Overall, the AAS-induced differential adaptive changes amounted to significant fiber type transformations in the fast-to-slow direction in SOL. AAS treatment had a significant effect on muscle weights and fiber type composition in SOL, TA and GAS which was

  20. Intermittent and continuous high-intensity exercise training induce similar acute but different chronic muscle adaptations.

    Science.gov (United States)

    Cochran, Andrew J R; Percival, Michael E; Tricarico, Steven; Little, Jonathan P; Cermak, Naomi; Gillen, Jenna B; Tarnopolsky, Mark A; Gibala, Martin J

    2014-05-01

    High-intensity interval training (HIIT) performed in an 'all-out' manner (e.g. repeated Wingate tests) is a time-efficient strategy to induce skeletal muscle remodelling towards a more oxidative phenotype. A fundamental question that remains unclear, however, is whether the intermittent or 'pulsed' nature of the stimulus is critical to the adaptive response. In study 1, we examined whether the activation of signalling cascades linked to mitochondrial biogenesis was dependent on the manner in which an acute high-intensity exercise stimulus was applied. Subjects performed either four 30 s Wingate tests interspersed with 4 min of rest (INT) or a bout of continuous exercise (CONT) that was matched for total work (67 ± 7 kJ) and which required ∼4 min to complete as fast as possible. Both protocols elicited similar increases in markers of adenosine monophosphate-activated protein kinase (AMPK) and p38 mitogen-activated protein kinase activation, as well as Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) mRNA expression (main effects for time, P ≤ 0.05). In study 2, we determined whether 6 weeks of the CONT protocol (3 days per week) would increase skeletal muscle mitochondrial content to a similar extent to what we have previously reported after 6 weeks of INT. Despite similar acute signalling responses to the CONT and INT protocols, training with CONT did not increase the maximal activity or protein content of a range of mitochondrial markers. However, peak oxygen uptake was higher after CONT training (from 45.7 ± 5.4 to 48.3 ± 6.5 ml kg(-1) min(-1); P muscle adaptations to low-volume, all-out HIIT. Despite the lack of skeletal muscle mitochondrial adaptations, our data show that a training programme based on a brief bout of high-intensity exercise, which lasted <10 min per session including warm-up, and performed three times per week for 6 weeks, improved peak oxygen uptake in young healthy subjects.

  1. Hormonal and Physiological Adaptations to High-Intensity Interval Training in Professional Male Canoe Polo Athletes.

    Science.gov (United States)

    Sheykhlouvand, Mohsen; Khalili, Erfan; Agha-Alinejad, Hamid; Gharaat, Mohammadali

    2016-03-01

    This study compared the effects of 2 different high-intensity interval training (HIIT) programs in professional male canoe polo athletes. Responses of peak oxygen uptake (VO2peak), ventilatory threshold (VT), peak and mean anaerobic power output (PPO and MPO), blood volume, and hormonal adaptations to HIIT were examined. Male athletes (n = 21, age: 24 ± 3 years; height: 181 ± 4 cm; mass: 85 ± 6 kg; and body fat: 12.9 ± 2.7%) were randomly assigned to one of 3 groups (N = 7): (a) (G1) interval paddling with variable volume (6, 7, 8, 9, 9, 9, 8, 7, 6 repetitions per session from first to ninth session, respectively) × 60 second at lowest velocity that elicited VO2peak (vVO2peak), 1:3 work to recovery ratio; (b) (G2) interval paddling with variable intensity (6 × 60 second at 100, 110, 120, 130, 130, 130, 120, 110, 100% vVO2peak from first to ninth session, respectively, 1:3 work to recovery); and (c) (GCON) the control group performed three 60 minutes paddling sessions (75% vVO2peak) per week for 3 weeks. High-intensity interval training resulted in significant (except as shown) increases compared with pretest, in VO2peak (G1 = +8.8% and G2 = +8.5%), heart rate at VT (b·min) (G1 = +9.7% and G2 = +5.9%) and (%maximum) (G1 = +6.9%; p = 0.29 and G2 = +6.5%), PPO (G1 = +9.7% and G2 = +12.2%), MPO (G1 = +11.1%; p = 0.29 and G2 = +16.2%), total testosterone (G1 = +29.4% and G2 = +16.7%), total testosterone/cortisol ratio (G1 = +40.9% and G2 = +28.1%), and mean corpuscular hemoglobin (G1 = +1.7% and G2 = +1.3%). No significant changes were found in GCON. High-intensity interval paddling may improve both aerobic and anaerobic performances in professional male canoe polo athletes under the conditions of this study.

  2. The impact of brief high-intensity exercise on blood glucose levels

    Directory of Open Access Journals (Sweden)

    Adams OP

    2013-02-01

    Full Text Available O Peter AdamsFaculty of Medical Sciences, the University of the West Indies, Cave Hill Campus, St Michael, BarbadosBackground: Moderate-intensity exercise improves blood glucose (BG, but most people fail to achieve the required exercise volume. High-intensity exercise (HIE protocols vary. Maximal cycle ergometer sprint interval training typically requires only 2.5 minutes of HIE and a total training time commitment (including rest and warm up of 25 minutes per session. The effect of brief high-intensity exercise on blood glucose levels of people with and without diabetes is reviewed.Methods: HIE (≥80% maximal oxygen uptake, VO2max studies with ≤15 minutes HIE per session were reviewed.Results: Six studies of nondiabetics (51 males, 14 females requiring 7.5 to 20 minutes/week of HIE are reviewed. Two weeks of sprint interval training increased insulin sensitivity up to 3 days postintervention. Twelve weeks near maximal interval running (total exercise time 40 minutes/week improved BG to a similar extent as running at 65% VO2max for 150 minutes/week. Eight studies of diabetics (41 type 1 and 22 type 2 subjects were reviewed. Six were of a single exercise session with 44 seconds to 13 minutes of HIE, and the others were 2 and 7 weeks duration with 20 and 2 minutes/week HIE, respectively. With type 1 and 2 diabetes, BG was generally higher during and up to 2 hours after HIE compared to controls. With type 1 diabetics, BG decreased from midnight to 6 AM following HIE the previous morning. With type 2 diabetes, a single session improved postprandial BG for 24 hours, while a 2-week program reduced the average BG by 13% at 48 to 72 hours after exercise and also increased GLUT4 by 369%.Conclusion: Very brief HIE improves BG 1 to 3 days postexercise in both diabetics and nondiabetics. HIE is unlikely to cause hypoglycemia during and immediately after exercise. Larger and longer randomized studies are needed to determine the safety, acceptability, long

  3. Five Weeks of Sprint and High-Intensity Interval Training Improves Paddling Performance in Adolescent Surfers.

    Science.gov (United States)

    Farley, Oliver R L; Secomb, Josh L; Parsonage, Joanna R; Lundgren, Lina E; Abbiss, Chris R; Sheppard, Jeremy M

    2016-09-01

    Farley, ORL, Secomb, JL, Parsonage, JR, Lundgren, LE, Abbiss, CR, and Sheppard, JM. Five weeks of sprint and high-intensity interval training improves paddling performance in adolescent surfers. J Strength Cond Res 30(9): 2446-2452, 2016-The purpose of our study was to examine the effects of sprint interval training (SIT; 10 seconds) and high-intensity interval training (HIT; 30 seconds) on surfing athletes paddling performance (400-m time trial and repeat-sprint paddle performance). Twenty-four competitive adolescent surfers (19 male, 5 female; age = 14.4 ± 1.3 years, mass: 50.1 ± 10.7 kg, and stature: 159.9 ± 10.3 cm) were assigned to perform either 5 weeks of SIT and HIT. Participants completed a repeated-sprint paddle ability test (RSPT, 15-m surfboard sprint paddle initiated every 40 seconds × 10 bouts) and 400-m endurance surfboard paddle time trial before and after training. High-intensity interval training decreased the total time to complete the 400 m by 15.8 ± 16.1 seconds (p = 0.03), and SIT decreased the total time to complete the RSPT by 6.5 ± 4.3 seconds (p = 0.02). Fatigue index during the RSPT (first-slowest effort) was lower after HIT and SIT (p ≤ 0.001 and p = 0.02, respectively). There were no significant differences in performance changes in the 400 m (total time) and RSPT (total time, fastest 15 m time, and peak velocity) between HIT and SIT. Our study indicates that HIT and SIT may be implemented to the training program of surfers to improve aerobic and repeat-sprint paddle ability, both of which are identified as key aspects of the sport. In addition, these findings indicate that 400-m paddle and RSPT can discriminate between aerobic and anaerobic training adaptations, with aerobic gains likely from HIT and anaerobic gains from SIT.

  4. High-intensity laser-accelerated ion beam produced from cryogenic micro-jet target

    Energy Technology Data Exchange (ETDEWEB)

    Gauthier, M., E-mail: maxence.gauthier@stanford.edu; Kim, J. B.; Curry, C. B.; Gamboa, E. J.; Göde, S.; Propp, A.; Glenzer, S. H. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Aurand, B.; Willi, O. [Heinrich-Heine-University Düsseldorf, Düsseldorf (Germany); Goyon, C.; Hazi, A.; Pak, A.; Ruby, J.; Williams, G. J. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Kerr, S. [University of Alberta, Edmonton, Alberta T6G 1R1 (Canada); Ramakrishna, B. [Indian Institute of Technology, Hyderabad (India); Rödel, C. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Friedrich-Schiller-University Jena, Jena (Germany)

    2016-11-15

    We report on the successful operation of a newly developed cryogenic jet target at high intensity laser-irradiation. Using the frequency-doubled Titan short pulse laser system at Jupiter Laser Facility, Lawrence Livermore National Laboratory, we demonstrate the generation of a pure proton beam a with maximum energy of 2 MeV. Furthermore, we record a quasi-monoenergetic peak at 1.1 MeV in the proton spectrum emitted in the laser forward direction suggesting an alternative acceleration mechanism. Using a solid-density mixed hydrogen-deuterium target, we are also able to produce pure proton-deuteron ion beams. With its high purity, limited size, near-critical density, and high-repetition rate capability, this target is promising for future applications.

  5. Microbubble mediated dual-frequency high intensity focused ultrasound thrombolysis: An In vitro study

    Science.gov (United States)

    Suo, Dingjie; Jin, Zhiyang; Jiang, Xiaoning; Dayton, Paul A.; Jing, Yun

    2017-01-01

    High intensity focused ultrasound (HIFU) has recently emerged as a promising alternative approach for thrombolysis. However, the high acoustic energy required by HIFU could elicit thermal damage bioeffects, impeding the clinical translation of this technique. This paper investigates the use of dual-frequency focused ultrasound (DFFU) mediated by microbubbles (MBs) to minimize the acoustic power required for thrombolysis in vitro. It was found that MBs, with sufficient concentration, could significantly lower the power threshold for thrombolysis for both DFFU and single-frequency focused ultrasound (SFFU). In addition, SFFU needs about 96%-156% higher energy to achieve the same thrombolysis efficiency as that of DFFU. The thrombolysis efficiency is also found to increase with the duty cycle. The measured cavitation signals reveal that the enhanced inertial cavitation is likely responsible for the improved thrombolysis under DFFU and MBs.

  6. Optimisation extraction of chondroitin sulfate from fish bone by high intensity pulsed electric fields.

    Science.gov (United States)

    He, Guidan; Yin, Yongguang; Yan, Xiaoxia; Yu, Qingyu

    2014-12-01

    High intensity pulsed electric fields (PEF) was used to extract chondroitin sulphate (CS) from fish bone. Results show that PEF extraction speed is much faster, and the content of CS is much higher compared with traditional methods. Variation of PEF parameters and the content of CS were determined by single factor experiments. The processing conditions were optimised by quadratic general rotary unitised design experiments. The maximum yield of 6.92 g/L was achieved under the following conditions: material-liquid ratio of 1:15 g/mL, electric field intensity of 16.88 kV/cm, pulse number of 9, and NaOH concentration of 3.24%. The purity of CS was analysed by agarose gel electrophoresis. CS purity was high, and the extract did not contain any other glycosaminoglycans. PEF can be widely used to extract CS with non-thermal performance, high speed, and low pollution.

  7. Responses of the Equatorial Ionosphere to High Intensity Long Duration Continuous Auroral Activity

    Science.gov (United States)

    Sobral, J. H. A.; Abdu, M. A.; Gonzalez, W. D.; Gonzalez, A. C.; Tsurutani, B.; Daniela, D. C.; Arruda, C. S.

    This work focus the responses of the equatorial ionosphere over South America to intense substorms and, on the other hand, in the absence of magnetic storms. The substorms here concerned are related to what is known as High Intensity Long Duration Continuous Auroral Activity HILDCAA's. The analysis of these responses are carried out by means of ground-based ionosonde data from Fortaleza (3° 53'S 38° 25'W dip 2.7S for the epoch 1978-1979) and Cachoeira Paulista (22° 41'S , 45° 00W, dip 25.6S for 1978-1979)and ISEE-3 (Interplanetary Sun-Earth Explorer) satellite data during the 1978-1979 time frame. The substorm disturbed days are compared with the averages of quiet days. The ionospheric height variations are analyzed in the light of satellite data and intercomparisons of the two stations.

  8. Design, construction, activation, and operation of a high intensity acoustic test chamber

    Science.gov (United States)

    Kamel, L. T.

    1986-01-01

    The design philosophy, construction, integration, and activation of the high intensity acoustic test chamber for production acceptance testing of satellites are discussed. The 32,000 cubic-foot acoustic test cell consists of a steel reinforced concrete chamber with six electropneumatic noise generators. One of the innovative features of the chamber is a unique quarter horn assembly that acoustically couples the noise generators to the chamber. Design concepts, model testing, and evaluation results are presented. Considerations such as nitrogen versus compressed air source, digital closed loop spectrum control versus manual equalizers, and microprocessor based interlock systems are included. Construction difficulties, anomalies encountered, and their resolution are also discussed. Results of the readiness testing are highlighted.

  9. 76 FR 44613 - Designation of Eight Counties as High Intensity Drug Trafficking Areas

    Science.gov (United States)

    2011-07-26

    ...The Director of the Office of National Drug Control Policy has designated eight additional counties as High Intensity Drug Trafficking Areas pursuant to 21 U.S.C. 1706. The new counties are (1) Orange County in New York as part of the New York/New Jersey HIDTA; (2) Medocino County in California as part of the Northern California HIDTA; (3) Porter County in Indiana as part of the Lake County HIDTA; (4) Lexington and Richland Counties in South Carolina as part of the Atlanta HIDTA; (5) Harford County in Maryland as part of the Washington/Baltimore HIDTA; (6) Putnam and Mercer Counties in West Virginia as part of the Appalachia HIDTA.

  10. Interpretation of transverse tune spectra in a heavy-ion synchrotron at high intensities

    Directory of Open Access Journals (Sweden)

    R. Singh

    2013-03-01

    Full Text Available Two different tune measurement systems have been installed in the GSI Helmholtzzentrum für Schwerionenforschung heavy-ion synchrotron SIS-18. Tune spectra are obtained with high accuracy using these fast and sensitive systems. Besides the machine tune, the spectra contain information about the intensity dependent coherent tune shift and the incoherent space charge tune shift. The space charge tune shift is derived from a fit of the observed shifted positions of the synchrotron satellites to an analytic expression for the head-tail eigenmodes with space charge. Furthermore, the chromaticity is extracted from the measured head-tail mode structure. The results of the measurements provide experimental evidence of the importance of space charge effects and head-tail modes for the interpretation of transverse beam signals at high intensity.

  11. Interpretation of transverse tune spectra in a heavy-ion synchrotron at high intensities

    CERN Document Server

    Singh, R; Chorniy, O; Forck, P; Haseitl, R; Kaufmann, W; Kowina, P; Lang, K; Weiland, T

    2012-01-01

    Two different tune measurement systems have been installed in the GSI heavy-ion synchrotron SIS-18. Tune spectra are obtained with high accuracy using these fast and sensitive systems. Besides the machine tune, the spectra contain information about the intensity dependent coherent tune shift and the incoherent space charge tune shift. The space charge tune shift is derived from a fit of the observed shifted positions of the synchrotron satellites to an analytic expression for the head-tail eigenmodes with space charge. Furthermore, the chromaticity is extracted from the measured head-tail mode structure. The results of the measurements provide experimental evidence of the importance of space charge effects and head-tail modes for the interpretation of transverse beam signals at high intensity.

  12. Salutary effects of high-intensity interval training in persons with elevated cardiovascular risk

    Science.gov (United States)

    Fleg, Jerome L.

    2016-01-01

    Although moderate-intensity continuous training (MICT) has been the traditional model for aerobic exercise training for over four decades, a growing body of literature has demonstrated equal if not greater improvement in aerobic capacity and similar beneficial effects on body composition, glucose metabolism, blood pressure, and quality of life from high-intensity interval training (HIIT). An advantage of HIIT over MICT is the shorter time required to perform the same amount of energy expenditure. The current brief review summarizes the effects of HIIT on peak aerobic capacity and cardiovascular risk factors in healthy adults and those with various cardiovascular diseases, including coronary artery disease, chronic heart failure, and post heart transplantation. PMID:27635241

  13. An FEL based high-intensity gamma source at the TESLA Test Facility at DESY

    CERN Document Server

    Pagani, C; Schneidmiller, E A; Yurkov, M V

    1999-01-01

    One possible extension of the FEL activity at DESY is connected with the installation of an additional FEL beamline providing tunable UV radiation with peak and average power of 220 GW and 7 kW, respectively. This report presents the feasibility study of a high-intensity, polarized, monochromatic gamma source at the TESLA Test Facility. Gamma quanta are produced in the process of Compton backscattering of the UV FEL radiation on 1 GeV electrons of the TTF accelerator. The ultimate intensity of the gamma source can reach a value up to 10 sup 1 sup 2 gamma quanta per second with a maximum energy of about 100 MeV. The energy resolution of the gamma source can be reduced down to a value of about 0.2%. Potential applications of the intense gamma source at the TESLA Test Facility are discussed as well.

  14. High-intensity power-resolved radiation imaging of an operational nuclear reactor

    Science.gov (United States)

    Beaumont, Jonathan S.; Mellor, Matthew P.; Villa, Mario; Joyce, Malcolm J.

    2015-01-01

    Knowledge of the neutron distribution in a nuclear reactor is necessary to ensure the safe and efficient burnup of reactor fuel. Currently these measurements are performed by in-core systems in what are extremely hostile environments and in most reactor accident scenarios it is likely that these systems would be damaged. Here we present a compact and portable radiation imaging system with the ability to image high-intensity fast-neutron and gamma-ray fields simultaneously. This system has been deployed to image radiation fields emitted during the operation of a TRIGA test reactor allowing a spatial visualization of the internal reactor conditions to be obtained. The imaged flux in each case is found to scale linearly with reactor power indicating that this method may be used for power-resolved reactor monitoring and for the assay of ongoing nuclear criticalities in damaged nuclear reactors. PMID:26450669

  15. The Efficacy of High-Intensity Focused Ultrasound (HIFU) in Advanced Pancreatic Cancer

    Institute of Scientific and Technical Information of China (English)

    Bo Xie; Jiajun Ling; Weiming Zhang; Xueqin Huang; Jihua Zhen; Yanzhe Huang

    2008-01-01

    OBJECTIVE To observe the efficacy of high-intensity focused ultrasound (HIFU)in the treatment of late-stage pancreatic cancer.METHODS Sixteen patients with advanced pancreatic cancer received HIFU therapy.Evaluation of efficacy was made on the basis of changes in clinical symptoms and variations in the tumor echo and size.RESULTS Clinical symptoms such as pain were significantly alleviated,echo of the tumor was enhanced with B-US and the quality of life such as eating,sleeping and mental status was markedly improved;no serious complications were observed.CONCLUSION The use of HIFU in the treatment of advanced pancreatic cancer is feasible and safe.It is effective in killing the carcinoma cells and alleviaring pain.This technique may offer non-invasive therapy for the treatment of patients with late-stage pancreatic cancer.

  16. Improved highly accurate localized motion imaging for monitoring high-intensity focused ultrasound therapy

    Science.gov (United States)

    Qu, Xiaolei; Azuma, Takashi; Sugiyama, Ryusuke; Kanazawa, Kengo; Seki, Mika; Sasaki, Akira; Takeuchi, Hideki; Fujiwara, Keisuke; Itani, Kazunori; Tamano, Satoshi; Takagi, Shu; Sakuma, Ichiro; Matsumoto, Yoichiro

    2016-07-01

    Visualizing an area subjected to high-intensity focused ultrasound (HIFU) therapy is necessary for controlling the amount of HIFU exposure. One of the promising monitoring methods is localized motion imaging (LMI), which estimates coagulation length by detecting the change in stiffness. In this study, we improved the accuracy of our previous LMI by dynamic cross-correlation window (DCCW) and maximum vibration amount (MVA) methods. The DCCW method was used to increase the accuracy of estimating vibration amplitude, and the MVA method was employed to increase signal-noise ratio of the decrease ratio at the coagulated area. The qualitative comparison of results indicated that the two proposed methods could suppress the effect of noise. Regarding the results of the quantitative comparison, coagulation length was estimated with higher accuracy by the improved LMI method, and the root-mean-square error (RMSE) was reduced from 2.51 to 1.69 mm.

  17. A mask for high-intensity heavy-ion beams in the MAYA active target

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez-Tajes, C., E-mail: rodriguez@ganil.fr [Grand Accélérateur National d' Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, Bvd Henri Becquerel, 14076 Caen (France); Universidade de Santiago de Compostela, E-15706 Santiago de Compostela (Spain); Pancin, J.; Damoy, S.; Roger, T.; Babo, M. [Grand Accélérateur National d' Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, Bvd Henri Becquerel, 14076 Caen (France); Caamaño, M. [Universidade de Santiago de Compostela, E-15706 Santiago de Compostela (Spain); Farget, F.; Grinyer, G.F.; Jacquot, B.; Pérez-Loureiro, D. [Grand Accélérateur National d' Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, Bvd Henri Becquerel, 14076 Caen (France); Ramos, D. [Universidade de Santiago de Compostela, E-15706 Santiago de Compostela (Spain); Suzuki, D. [Institut de Physique Nucléaire, Université Paris-Sud 11, CNRS/IN2P3, F-91406 Orsay (France)

    2014-12-21

    The use of high-intensity and/or heavy-ion beams in active targets and time-projection chambers is often limited by the strong ionization produced by the beam. Besides the difficulties associated with the saturation of the detector and electronics, beam-related signals may hide the physical events of interest or reduce the detector performance. In addition, space-charge effects may deteriorate the homogeneity of the electric drift field and distort the subsequent reconstruction of particle trajectories. In anticipation of future projects involving such conditions, a dedicated beam mask has been developed and tested in the MAYA active target. Experimental results with a {sup 136}Xe beam are presented.

  18. A mask for high-intensity heavy-ion beams in the MAYA active target

    Science.gov (United States)

    Rodríguez-Tajes, C.; Pancin, J.; Damoy, S.; Roger, T.; Babo, M.; Caamaño, M.; Farget, F.; Grinyer, G. F.; Jacquot, B.; Pérez-Loureiro, D.; Ramos, D.; Suzuki, D.

    2014-12-01

    The use of high-intensity and/or heavy-ion beams in active targets and time-projection chambers is often limited by the strong ionization produced by the beam. Besides the difficulties associated with the saturation of the detector and electronics, beam-related signals may hide the physical events of interest or reduce the detector performance. In addition, space-charge effects may deteriorate the homogeneity of the electric drift field and distort the subsequent reconstruction of particle trajectories. In anticipation of future projects involving such conditions, a dedicated beam mask has been developed and tested in the MAYA active target. Experimental results with a 136Xe beam are presented.

  19. RADIATION DOSE MEASUREMENTS FOR HIGH-INTENSITY LASER INTERACTIONS WITH SOLID TARGETS AT SLAC.

    Science.gov (United States)

    Liang, T; Bauer, J; Cimeno, M; Ferrari, A; Galtier, E; Granados, E; Lee, H J; Liu, J; Nagler, B; Prinz, A; Rokni, S; Tran, H; Woods, M

    2016-12-01

    A systematic study of photon and neutron radiation doses generated in high-intensity laser-solid interactions is underway at SLAC National Accelerator Laboratory. These laser-solid experiments are being performed using a 25 TW (up to 1 J in 40 fs) femtosecond pulsed Ti:sapphire laser at the Linac Coherent Light Source's (LCLS) Matter in Extreme Conditions (MEC) facility. Radiation measurements were performed with passive and active detectors deployed at various locations inside and outside the target chamber. Results from radiation dose measurements for laser-solid experiments at SLAC MEC in 2014 with peak intensity between 10(18) and 7.1 × 10(19) W cm(-2) are presented.

  20. Self-organization of high intensity laser pulses propagating in gases

    Energy Technology Data Exchange (ETDEWEB)

    Koga, James [Japan Atomic Energy Research Inst., Kizu, Kyoto (Japan). Kansai Research Establishment

    2001-10-01

    In recent years the development of high intensity short pulse lasers has opened up wide fields of science which had previously been difficult to study. Recent experiments of short pulse lasers propagating in air have shown that these laser pulses can propagate over very long distances (up to 12 km) with little or no distortion of the pulse. Here we present a model of this propagation using a modified version of the self-organized criticality model developed for sandpiles by Bak, Tang, and Weisenfeld. The additions to the sandpile model include the formation of plasma which acts as a threshold diffusion term and self-focusing by the nonlinear index of refraction which acts as a continuous inverse diffusion. Results of this simple model indicate that a strongly self-focusing laser pulse shows self-organized critical behavior. (author)

  1. Probing vacuum birefringence using x-ray free electron and optical high-intensity lasers

    CERN Document Server

    Karbstein, Felix

    2016-01-01

    Vacuum birefringence is one of the most striking predictions of strong field quantum electrodynamics: Probe photons traversing a strong field region can indirectly sense the applied "pump" electromagnetic field via quantum fluctuations of virtual charged particles which couple to both pump and probe fields. This coupling is sensitive to the field alignment and can effectively result in two different indices of refraction for the probe photon polarization modes giving rise to a birefringence phenomenon. In this article we perform a dedicated theoretical analysis of the proposed discovery experiment of vacuum birefringence at a x-ray free electron laser/optical high-intensity laser facility. Describing both pump and probe laser pulses realistically in terms of their macroscopic electromagnetic fields, we go beyond previous analyses by accounting for various effects not considered before in this context. Our study facilitates stringent quantitative predictions and optimizations of the signal in an actual experim...

  2. Probing vacuum birefringence using x-ray free electron and optical high-intensity lasers

    Science.gov (United States)

    Karbstein, Felix; Sundqvist, Chantal

    2016-07-01

    Vacuum birefringence is one of the most striking predictions of strong field quantum electrodynamics: Probe photons traversing a strong field region can indirectly sense the applied "pump" electromagnetic field via quantum fluctuations of virtual charged particles which couple to both pump and probe fields. This coupling is sensitive to the field alignment and can effectively result in two different indices of refraction for the probe photon polarization modes giving rise to a birefringence phenomenon. In this article, we perform a dedicated theoretical analysis of the proposed discovery experiment of vacuum birefringence at an x-ray free electron laser/optical high-intensity laser facility. Describing both pump and probe laser pulses realistically in terms of their macroscopic electromagnetic fields, we go beyond previous analyses by accounting for various effects not considered before in this context. Our study facilitates stringent quantitative predictions and optimizations of the signal in an actual experiment.

  3. High-intensity Exercise Modifies the Effects of Stanozolol on Brain Oxidative Stress in Rats.

    Science.gov (United States)

    Camiletti-Moirón, D; Aparicio, V A; Nebot, E; Medina, G; Martínez, R; Kapravelou, G; Andrade, A; Porres, J M; López-Jurado, M; Aranda, P

    2015-11-01

    We analyzed the effects of high-intensity exercise (HIE) and anabolic androgenic steroids (AAS) on brain redox status. 40 male Wistar rats were randomly distributed in 4 experimental groups (n=10) with or without HIE and with or without weekly Stanozolol administration. Thiobarbituric acid-reactive substances (TBARs) and protein carbonyl content (PCC) were assessed. Total superoxide dismutase (tSOD), manganese superoxide dismutase (Mn-SOD), copper/zinc superoxide dismutase (CuZn-SOD) and catalase (CAT) activities were measured. Finally, protein expression levels of glutathione peroxidase (GPx), NAD(P)H dehydrogenase, Quinone 1 (NQO1), NF-E2-Related Factor 2 (Nrf2), glial fibrillary acidic protein (GFAP), nuclear factor kappa β p65 (NF-κβ) and signal transducer and activator of transcription 3 were determined. Brain PCC concentrations were lower in the HIE groups compared to the untrained controls, whereas CAT activity was higher (both, peffect on brain redox status.

  4. Electron Acceleration and the Propagation of Ultrashort High-Intensity Laser Pulses in Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaofang; Krishnan, Mohan; Saleh, Ned; Wang, Haiwen; Umstadter, Donald

    2000-06-05

    Reported are interactions of high-intensity laser pulses ({lambda}=810 nm and I{<=}3x10{sup 18} W /cm{sup 2} ) with plasmas in a new parameter regime, in which the pulse duration ({tau}=29 fs ) corresponds to 0.6-2.6 plasma periods. Relativistic filamentation is observed to cause laser-beam breakup and scattering of the beam out of the vacuum propagation angle. A beam of megaelectronvolt electrons with divergence angle as small as 1 degree sign is generated in the forward direction, which is correlated to the growth of the relativistic filamentation. Raman scattering, however, is found to be much less than previous long-pulse results. (c) 2000 The American Physical Society.

  5. High intensity and reduced volume training attenuates stress and recovery levels in elite swimmers

    DEFF Research Database (Denmark)

    Elbe, Anne-Marie; Rasmussen, Camilla P; Nielsen, Glen

    2016-01-01

    for baseline values. No significant effects could be observed in sports-specific stress or sports-specific recovery. The results indicate that increasing training intensity and reducing training volume for 12 weeks can reduce general stress and increase general recovery levels in competitive swimmers.......This study investigated the effect of increased high-intensity interval training (HIT) at the expense of total training volume on the stress and recovery levels of elite swimmers. Forty-one elite swimmers participated in the study and were randomly assigned to either a HIT or a control group (CON......). Eleven swimmers did not complete the questionnaires. For 12 weeks both groups trained ~12 h per week. The amount of HIT was ~5 h vs. 1 h, and total distance was ~17 km vs. ~35 km per week for HIT and CON, respectively. HIT was performed as 6-10 × 10-30 s maximal effort interspersed by 2-4 min of rest...

  6. Channeling of multikilojoule high-intensity laser beams in an inhomogeneous plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ivancic, S. [Univ. of Rochester, Rochester, NY (United States); Haberberger, D. [Univ. of Rochester, Rochester, NY (United States); Habara, H. [Osaka Univ., Suita (Japan); Iwawaki, T. [Osaka Univ., Suita (Japan); Anderson, K. S. [Univ. of Rochester, Rochester, NY (United States); Craxton, R. S. [Univ. of Rochester, Rochester, NY (United States); Froula, D. H. [Univ. of Rochester, Rochester, NY (United States); Meyerhofer, D. D. [Univ. of Rochester, Rochester, NY (United States); Stoeckl, C. [Univ. of Rochester, Rochester, NY (United States); Tanaka, K. A. [Osaka Univ., Suita (Japan); Theobald, W. [Univ. of Rochester, Rochester, NY (United States)

    2015-05-01

    Channeling experiments were performed that demonstrate the transport of high-intensity (>10¹⁸ W/cm²), multikilojoule laser light through a millimeter-sized, inhomogeneous (~300-μm density scale length) laser produced plasma up to overcritical density, which is an important step forward for the fast-ignition concept. The background plasma density and the density depression inside the channel were characterized with a novel optical probe system. The channel progression velocity was measured, which agrees well with theoretical predictions based on large scale particle-in-cell simulations, confirming scaling laws for the required channeling laser energy and laser pulse duration, which are important parameters for future integrated fast-ignition channeling experiments.

  7. Initial Results on Neutralized Drift Compression Experiments (NDCX-IA) for High Intensity Ion Beam

    CERN Document Server

    Roy, Prabir K; Baca, David; Bieniosek, Frank; Coleman, Joshua E; Davidson, Ronald C; Efthimion, Philip; Eylon, Shmuel; Gilson, Erik P; Grant Logan, B; Greenway, Wayne; Henestroza, Enrique; Kaganovich, Igor D; Leitner, Matthaeus; Rose, David; Sefkow, Adam; Sharp, William M; Shuman, Derek; Thoma, Carsten H; Vanecek, David; Waldron, William; Welch, Dale; Yu, Simon

    2005-01-01

    Ion beam neutralization and compression experiments are designed to determine the feasibility of using compressed high intensity ion beams for high energy density physics (HEDP) experiments and for inertial fusion power. To quantitatively ascertain the various mechanisms and methods for beam compression, the Neutralized Drift Compression Experiment (NDCX) facility is being constructed at Lawrence Berkeley National Laboratory (LBNL). In the first compression experiment, a 260 KeV, 25 mA, K+ ion beam of centimeters size is radially compressed to a mm size spot by neutralization in a meter-long plasma column and beam peak current is longitudinally compressed by an induction velocity tilt core. Instrumentation, preliminary results of the experiments, and practical limits of compression are presented. These include parameters such as emittance, degree of neutralization, velocity tilt time profile, and accuracy of measurements (fast and spatially high resolution diagnostic) are discussed.

  8. A Rectourethral Fistula due to Transrectal High-Intensity Focused Ultrasound Treatment: Diagnosis and Management.

    Science.gov (United States)

    Fiaschetti, Valeria; Manenti, Guglielmo; Di Poce, Isabelle; Fornari, Maria; Ricci, Aurora; Finazzi Agrò, Enrico; Simonetti, Giovanni

    2012-01-01

    Colovesical fistula (CVF) is an abnormal connection between the enteric and the urinary systems. The rectourethral fistula (RUF) is a possible but extremely rare complication of treatment of prostate cancer with "transrectal High-Intensity Focused Ultrasound (HIFU) treatment." We present a case of CVF due to HIFU treatment of recurrent prostate cancer. The case was assessed with cystography completed with a pelvic CT scan-with MPR, MIP, and VR reconstruction-before emptying the bladder. Since the CT scan confirmed that the fistula involved solely the urethra and excluded even a minimal involvement of the bladder, it was possible to employ a conservative treatment by positioning a Foley catheter of monthly duration, in order to allow the urethra to rest. Still today, after 6 months, the patient is in a good clinical condition and has not shown yet signs of a recurrence of the fistula.

  9. Backcoupling of acoustic streaming on the temperature field inside high-intensity discharge lamps

    CERN Document Server

    Schwieger, Joerg; Wolff, Marcus; Manders, Freddy; Suijker, Jos

    2015-01-01

    Operating high-intensity discharge lamps in the high frequency range (20-300 kHz) provides energy-saving and cost reduction potentials. However, commercially available lamp drivers do not make use of this operating strategy because light intensity fluctuations and even lamp destruction are possible. The reason for the fluctuating discharge arc are acoustic resonances in this frequency range that are excited in the arc tube. The acoustic resonances in turn generate a fluid flow that is caused by the acoustic streaming effect. Here, we present a 3D multiphysics model to determine the influence of acoustic streaming on the temperature field in the vicinity of an acoustic eigenfrequency. In that case a transition from stable to instable behavior occurs. The model is able to predict when light flicker can be expected. The results are in very good accordance with accompanying experiments.

  10. Real-time feedback control for high-intensity focused ultrasound system using localized motion imaging

    Science.gov (United States)

    Sugiyama, Ryusuke; Kanazawa, Kengo; Seki, Mika; Azuma, Takashi; Sasaki, Akira; Takeuchi, Hideki; Fujiwara, Keisuke; Itani, Kazunori; Tamano, Satoshi; Yoshinaka, Kiyoshi; Takagi, Shu; Matsumoto, Yoichiro

    2015-07-01

    High-intensity focused ultrasound (HIFU) is one of the noninvasive treatment for tumors. Visualizing the treated area inside the human body is necessary to control the HIFU exposure. Localized motion imaging (LMI) using ultrasound to induce and detect tissue deformation is one technique to detect a change in tissue stiffness caused by thermal coagulation. In experiments with porcine liver, LMI has shown to detect deformation with less than 20% accuracy. We have developed a prototype feedback control system using real-time LMI. In this system, coagulation size was measured every 1 s and controlled to correspond to a targeted size. The typical size error was reduced to 14% from 35%. LMI displacements in normal and coagulated tissues were sufficiently different to discriminate between coagulated areas and noncoagulated ones after HIFU sonication and to visualize treated areas after HIFU treatment.

  11. Design Considerations of Fast Kicker Systems for High Intensity Proton Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, W; Sandberg, J; Parson, W M; Walstrom, P; Murray, M M; Cook, E; Hartouni, E

    2001-06-12

    In this paper, we discuss the specific issues related to the design of the Fast Kicker Systems for high intensity proton accelerators. To address these issues in the preliminary design stage can be critical since the fast kicker systems affect the machine lattice structure and overall design parameters. Main topics include system architecture, design strategy, beam current coupling, grounding, end user cost vs. system cost, reliability, redundancy and flexibility. Operating experience with the Alternating Gradient Synchrotron injection and extraction kicker systems at Brookhaven National Laboratory and their future upgrade is presented. Additionally, new conceptual designs of the extraction kicker for the Spallation Neutron Source at Oak Ridge and the Advanced Hydrotest Facility at Los Alamos are discussed.

  12. Simulations On Pair Creation In Collision Of γ-Beams Produced With High Intensity Lasers

    Science.gov (United States)

    Jansen, Oliver; Ribeyre, Xavier; D'Humieres, Emmanuel; Lobet, Mathieu; Jequier, Sophie; Tikhonchuk, Vladimir

    2016-10-01

    Direct production of electron-positron pairs in two photon collisions, the Breit-Wheeler process, is one of the most basic processes in the universe. However, this process has never been directly observed in the laboratory due to the lack of high intensity γ sources. For a feasibility study and for the optimisation of experimental set-ups we developed a high-performance tree-code. Different possible set-ups with MeV photon sources were discussed and compared using collision detection for huge number of particles in a quantum-electrodynamic regime. The authors acknowledge the financial support from the French National Research Agency (ANR) in the framework of ''The Investments for the Future'' programme IdEx Bordeaux - LAPHIA (ANR-10IDEX-03-02)-Project TULIMA.

  13. Benchmark of Space Charge Simulations and Comparison with Experimental Results for High Intensity, Low Energy Accelerators

    CERN Document Server

    Cousineau, Sarah M

    2005-01-01

    Space charge effects are a major contributor to beam halo and emittance growth leading to beam loss in high intensity, low energy accelerators. As future accelerators strive towards unprecedented levels of beam intensity and beam loss control, a more comprehensive understanding of space charge effects is required. A wealth of simulation tools have been developed for modeling beams in linacs and rings, and with the growing availability of high-speed computing systems, computationally expensive problems that were inconceivable a decade ago are now being handled with relative ease. This has opened the field for realistic simulations of space charge effects, including detailed benchmarks with experimental data. A great deal of effort is being focused in this direction, and several recent benchmark studies have produced remarkably successful results. This paper reviews the achievements in space charge benchmarking in the last few years, and discusses the challenges that remain.

  14. Comparing Particle-in-Cell QED Models for High-Intensity Laser-Plasma Interactions

    Science.gov (United States)

    Luedtke, Scott V.; Labun, Lance A.; Hegelich, Björn Manuel

    2016-10-01

    High-intensity lasers, such as the Texas Petawatt, are pushing into new regimes of laser-matter interaction, requiring continuing improvement and inclusion of new physics effects in computer simulations. Experiments at the Texas Petawatt are reaching intensity regimes where new physics-quantum electrodynamics (QED) corrections to otherwise classical plasma dynamics-becomes important. We have two particle-in-cell (PIC) codes with different QED implementations. We review the theory of photon emission in QED-strong fields, and cover the differing PIC implementations. We show predictions from the two codes and compare with ongoing experiments. This work was supported by NNSA cooperative agreement DE-NA0002008, the Defense Advanced Research Projects Agency's PULSE program (12-63-PULSE-FP014) and the Air Force Office of Scientific Research (FA9550-14-1-0045). HPC resources provided by TACC.

  15. Investigations on the heating effect of PE-LD induced by high-intensity focused ultrasound.

    Science.gov (United States)

    Oehm, Lukas; Bach, Sascha; Majschak, Jens-Peter

    2016-08-01

    High-intensity focused ultrasound is widely applied in tissue treatment as well as for heating of solid polymer materials. Previous studies investigating the heating effect in polymer materials utilized sound transmission through water or other fluids at low HIFU power. In this study, the ultrasonic transducer possesses a solid sound conductor made of aluminum and a high HIFU power of above 100W was applied to heat solid PE-LD samples. Temperature measurements were performed by calibrated non-invasive infrared thermal imaging. A strong heating effect with heating above melting temperature and evaporation temperature within less than 1s of irradiation was observed. Furthermore, the acoustic coupling defined by the force applied by the ultrasonic applicator to the polymer material was found to be fundamental to induce the heating effect. This investigation reveals HIFU for new applications in the field of polymer processing.

  16. Detailed studies of Minor Actinide transmutation-incineration in high-intensity neutron fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Bringer, O. [CEA/Saclay/DSM/DAPNIA, Gif-sur-Yvette (France); Al Mahamid, I. [Lawrence Berkeley National Laboratory, E.H. and S. Div., CA (United States); Blandin, C. [CEA/Cadarache/DEN/DER/SPEX, Saint-Paul-lez-Durances (France); Chabod, S. [CEA/Saclay/DSM/DAPNIA, Gif-sur-Yvette (France); Chartier, F. [CEA/Cadarache/DEN/DPC/SECR, Gif-sur-Yvette (France); Dupont, E.; Fioni, G. [CEA/Saclay/DSM/DAPNIA, Gif-sur-Yvette (France); Isnard, H. [CEA/Cadarache/DEN/DPC/SECR, Gif-sur-Yvette (France); Letourneau, A.; Marie, F. [CEA/Saclay/DSM/DAPNIA, Gif-sur-Yvette (France); Mutti, P. [Institut Laue-Langevin, Grenoble (France); Oriol, L. [CEA/Cadarache/DEN/DER/SPEX, Saint-Paul-lez-Durances (France); Panebianco, S.; Veyssiere, C. [CEA/Saclay/DSM/DAPNIA, Gif-sur-Yvette (France)

    2006-07-01

    The Mini-INCA project is dedicated to the measurement of incineration-transmutation chains and potentials of minor actinides in high-intensity thermal neutron fluxes. In this context, new types of detectors and methods of analysis have been developed. The {sup 241}Am and {sup 232}Th transmutation-incineration chains have been studied and several capture and fission cross sections measured very precisely, showing some discrepancies with existing data or evaluated data. An impact study was made on different based-like GEN-IV reactors. It underlines the necessity to proceed to precise measurements for a large number of minor-actinides that contribute to these future incineration scenarios. (authors)

  17. A research plan based on high intensity proton accelerator Neutron Science Research Center

    Energy Technology Data Exchange (ETDEWEB)

    Mizumoto, Motoharu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    A plan called Neutron Science Research Center (NSRC) has been proposed in JAERI. The center is a complex composed of research facilities based on a proton linac with an energy of 1.5GeV and an average current of 10mA. The research facilities will consist of Thermal/Cold Neutron Facility, Neutron Irradiation Facility, Neutron Physics Facility, OMEGA/Nuclear Energy Facility, Spallation RI Beam Facility, Meson/Muon Facility and Medium Energy Experiment Facility, where high intensity proton beam and secondary particle beams such as neutron, pion, muon and unstable radio isotope (RI) beams generated from the proton beam will be utilized for innovative researches in the fields on nuclear engineering and basic sciences. (author)

  18. Dynamics of self-generated, large amplitude magnetic fields following high-intensity laser matter interaction

    CERN Document Server

    Sarri, G; Cecchetti, C A; Kar, S; Liseykina, T V; Yang, X H; Dieckmann, M E; Fuchs, J; Galimberti, M; Gizzi, L A; Jung, R; Kourakis, I; Osterholz, J; Pegoraro, F; Robinson, A P L; Romagnani, L; Willi, O; Borghesi, M

    2012-01-01

    The dynamics of magnetic fields with amplitude of several tens of Megagauss, generated at both sides of a solid target irradiated with a high intensity (? 1019W/cm2) picosecond laser pulse, has been spatially and temporally resolved using a proton imaging technique. The amplitude of the magnetic fields is sufficiently large to have a constraining effect on the radial expansion of the plasma sheath at the target surfaces. These results, supported by numerical simulations and simple analytical modeling, may have implications for ion acceleration driven by the plasma sheath at the rear side of the target as well as for the laboratory study of self-collimated high-energy plasma jets.

  19. Radiation Dose Measurement for High-Intensity Laser Interactions with Solid Targets at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Taiee [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-09-25

    A systematic study of photon and neutron radiation doses generated in high-intensity laser-solid interactions is underway at SLAC National Accelerator Laboratory. We found that these laser-solid experiments are being performed using a 25 TW (up to 1 J in 40 fs) femtosecond pulsed Ti:sapphire laser at the Linac Coherent Light Source’s (LCLS) Matter in Extreme Conditions (MEC) facility. Additionally, radiation measurements were performed with passive and active detectors deployed at various locations inside and outside the target chamber. Results from radiation dose measurements for laser-solid experiments at SLAC MEC in 2014 with peak intensity between 1018 to 7.1x1019 W/cm2 are presented.

  20. Relationship between the exposure dose of high intensity focused ultrasound and the heated necrosis element

    Institute of Scientific and Technical Information of China (English)

    FENG Ruo; ZHANG Qiang; LI Faqi; ZHENG Xiaozheng; BAI Jin; XU Jianyi; WANG Yaojun; WANG Zhibiao

    2004-01-01

    Heated necrosis element of tissues is the basis for treating tumor by high intensity focused ultrasound (HIFU), so study on the relationship between the HIFU exposure dose and the heated necrosis element of tissues is of great significance for both HIFU clinical applications and basic research. Using Pennes and Rayleigh formulae the relationship between the exposure dose of an annular focused transducer and the heated necrosis element (I.e. Biological focused region) in a bovine liver in vitro at a depth of 2 cm is simulated in an exposure dose range with radiation sound intensity of 7000~25400 W/cm2 and exposure time of 0~20 s. The theoretical results appear to be in quite good agreement with the experimental ones. It is shown that on the basis of existing theories the heated necrosis element produced by HIFU exposure can be predicted. The deviation of the theory from the experiments under higher exposure dose has also been discussed.

  1. Fabrication of silver nanoparticles by highly intense laser irradiation of aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Takahiro; Magara, Hideyuki; Herbani, Yuliati; Sato, Shunichi [Tohoku University, Institute of Multidisciplinary Research for Advanced Materials, Sendai (Japan)

    2011-09-15

    Silver (Ag) nanoparticles were fabricated by highly intense femtosecond laser irradiation of aqueous solutions of silver nitrate (AgNO{sub 3}) with various concentrations. After irradiation, a broad absorption peak at around 420 nm originating from surface plasmon resonance of Ag nanoparticles was observed in 30 and 300 mM solutions. Transmission electron microscopy revealed that Ag nanoparticles produced in 300 mM AgNO{sub 3} solution had a typical size in the range of 2 to 20 nm and a mean size of 4 nm. The addition of 1.0 x 10{sup -2} wt% polyvinylpyrrolidone as a dispersant to the 300 mM solution caused a narrower particle size distribution as well as a narrower absorption peak width after the laser irradiation. As a result, Ag nanoparticles with a mean particle size of about 2 nm were fabricated. (orig.)

  2. High intensity physical exercise and pain in the neck and upper limb among slaughterhouse workers

    DEFF Research Database (Denmark)

    Sundstrup, Emil; Jakobsen, Markus D.; Andersen, Kenneth Jay

    2014-01-01

    about the effect among workers with repetitive and forceful work demands. Before performing randomized controlled trials it may be beneficial to assess the cross-sectional connection between exercise and musculoskeletal pain. We investigated the association between high intensity physical exercise...... and pain among 595 slaughterhouse workers in Denmark, Europe. Using logistic regression analyses, odds ratios for pain and work disability as a function of physical exercise, gender, age, BMI, smoking, and job position were estimated. The prevalence of pain in the neck, shoulder, elbow, and hand....../wrist was 48%, 60%, 40%, and 52%, respectively. The odds for experiencing neck pain were significantly lower among slaughterhouse workers performing physical exercise (OR = 0.70, CI: 0.49-0.997), whereas the odds for pain in the shoulders, elbow, or hand/wrist were not associated with exercise. The present...

  3. Moderate-to-High Intensity Physical Exercise in Patients with Alzheimer's Disease: A Randomized Controlled Trial

    DEFF Research Database (Denmark)

    Hoffmann, Kristine; Sobol, Nanna A; Frederiksen, Kristian S

    2016-01-01

    Background: Studies of physical exercise in patients with Alzheimer’s disease (AD) are few and results have been inconsistent. Objective: To assess the effects of a moderate-to-high intensity aerobic exercise program in patients with mild AD. Methods: In a randomized controlled trial, we recruited...... 200 patients with mild AD to a supervised exercise group (60-min sessions three times a week for 16 weeks) or to a control group. Primary outcome was changed from baseline in cognitive performance estimated by Symbol Digit Modalities Test (SDMT) in the intention-to-treat (ITT) group. Secondary...... outcomes included changes in quality of life, ability to perform activities of daily living, and in neuropsychiatric and depressive symptoms. Results: The ITT analysis showed no significant differences between intervention and control groups in change from baseline of SDMT, other cognitive tests, quality...

  4. High-intensity power-resolved radiation imaging of an operational nuclear reactor

    Science.gov (United States)

    Beaumont, Jonathan S.; Mellor, Matthew P.; Villa, Mario; Joyce, Malcolm J.

    2015-10-01

    Knowledge of the neutron distribution in a nuclear reactor is necessary to ensure the safe and efficient burnup of reactor fuel. Currently these measurements are performed by in-core systems in what are extremely hostile environments and in most reactor accident scenarios it is likely that these systems would be damaged. Here we present a compact and portable radiation imaging system with the ability to image high-intensity fast-neutron and gamma-ray fields simultaneously. This system has been deployed to image radiation fields emitted during the operation of a TRIGA test reactor allowing a spatial visualization of the internal reactor conditions to be obtained. The imaged flux in each case is found to scale linearly with reactor power indicating that this method may be used for power-resolved reactor monitoring and for the assay of ongoing nuclear criticalities in damaged nuclear reactors.

  5. Final Report for "Modeling Electron Cloud Diagnostics for High-Intensity Proton Accelerators"

    Energy Technology Data Exchange (ETDEWEB)

    Seth A Veitzer

    2009-09-25

    Electron clouds in accelerators such as the ILC degrade beam quality and limit operating efficiency. The need to mitigate electron clouds has a direct impact on the design and operation of these accelerators, translating into increased cost and reduced performance. Diagnostic techniques for measuring electron clouds in accelerating cavities are needed to provide an assessment of electron cloud evolution and mitigation. Accurate numerical modeling of these diagnostics is needed to validate the experimental techniques. In this Phase I, we developed detailed numerical models of microwave propagation through electron clouds in accelerating cavities with geometries relevant to existing and future high-intensity proton accelerators such as Project X and the ILC. Our numerical techniques and simulation results from the Phase I showed that there was a high probability of success in measuring both the evolution of electron clouds and the effects of non-uniform electron density distributions in Phase II.

  6. Calculation of acceptance of high intensity superconducting proton linac for Project X

    CERN Document Server

    Saini, A; Solyak, N; Mishra, S; Yakovlev, V

    2011-01-01

    Project-X is the proposed high intensity proton facility to be built at Fermilab, US. Its Superconducting Linac, to be used at first stage of acceleration, will be operated in continuous wave (CW) mode. The Linac is divided into three sections on the basis of operating frequencies & six sections on the basis of family of RF cavities to be used for the acceleration of beam from 2.5 MeV to 3 GeV. The transition from one section to another can limit the acceptance of the Linac if these are not matched properly. We performed a study to calculate the acceptance of the Linac in both longitudinal and transverse plane. Investigation of most sensitive area which limits longitudinal acceptance and study of influence of failure of beam line elements at critical position, on acceptance are also performed.

  7. Effect of acoustic streaming on tissue heating due to high-intensity focused ultrasound

    CERN Document Server

    Solovchuk, Maxim A; Thiriet, Marc; Lin, Win-Li

    2011-01-01

    The influences of blood vessels and focused location on temperature distribution during high-intensity focused ultrasound (HIFU) ablation of liver tumors is studied. A three-dimensional acoustics-thermal-fluid coupling model is employed to compute the temperature field in the hepatic cancerous region. The model is based on the linear Westervelt and bioheat equations as well as the nonlinear Navier-Stokes equations for the liver parenchyma and blood vessels. The effect of acoustic streaming is also taken into account in the present HIFU simulation study. Different blood vessel diameters and focal point locations were investigated. We found from this three-dimensional numerical study that in large blood vessels both the convective cooling and acoustic streaming can change considerably the temperature field and the thermal lesion near blood vessels. If the blood vessel is located within the beam width, both acoustic streaming and blood flow cooling effects should be taken into account. The predicted temperature ...

  8. X-ray Absorption Imaging of High-Intensity Discharge Lamps Using Monochromatic Synchrotron Radiation

    Science.gov (United States)

    Curry, John J.; Sansonetti, Craig J.; Hechtfischer, Ulrich; Adler, Helmar G.

    2002-10-01

    We will report results from the imaging of Hg vapor in high-intensity discharge lamps using synchrotron radiation and digital detectors. These measurements extend previous work on x-ray absorption imaging in arc lamps using an x-ray tube and a passive phosphor image plate detector^i. The large x-ray flux obtained from the Advanced Photon Source (Argonne National Laboratory) combined with the electronic gating capabilities of an intensified charge-coupled device detector have allowed us to obtain time-resolved Hg distributions with high spatial resolution. Monochromatic synchrotron radiation improves the accuracy over what can be obtained with quasi-continuum radiation from an x-ray tube source. ^iJ. J. Curry, M. Sakai, and J. E. Lawler, Journal of Applied Physics 84, 3066 (1998).

  9. A radiation emission shielding method for high intensity focus ultrasound probes.

    Science.gov (United States)

    Wu, Hao; Shen, Guofeng; Chen, Yazhu

    2015-01-01

    Electromagnetic compatibility (EMC) is a key issue in the design and development of safe and effective medical instruments. The treatment probes of high intensity focused ultrasound (HIFU) systems not only receive and transmit electromagnetic waves, but also radiate ultrasound waves, resulting in electromagnetic coupling. In this paper, an electromagnetic shielding method involving the enclosure of the probe in a copper wire mesh was introduced. First, sound pressure distribution simulations and measurements were performed using a hydrophone in order to evaluate the effects of the wire mesh on the acoustic performance of the HIFU system. The results indicated that the wire mesh did not disturb the normalized sound pressure field. In addition, the attenuation of the maximum pressure in the focal plane was equal to 6.2%. Then, the electronic emission level was tested in a chamber. After the implementation of the wire mesh, the 10-100 MHz frequency band radiation was suppressed, and the HIFU system satisfied the national EMC standards.

  10. Enhancement of CO2 capture in limestone and dolomite granular beds by high intensity sound waves

    Science.gov (United States)

    Valverde, Jose Manuel; Perez-Ebri, Jose Manuel; Sanchez-Quintanilla, Miguel Angel

    2017-06-01

    The calcium looping (CaL) process, based on the calcination/carbonation of CaCO3 at high temperatures, has emerged in the last years as a potentially low cost technology for CO2 capture. In this work, we show that the application of high intensity sound waves to granular beds of limestone and dolomite in a CaL reactor enhances significantly their multicycle CO2 capture capacity. Sound waves are applied either during the calcination stage of each CaL cycle or in the carbonation stage. The effect of sound is to intensify the transfer of heat, mass and momentum and is more marked when sound is applied during calcination by promoting CaO regeneration. The application of sound would allow reducing the calcination temperature thereby mitigating the decay of capture capacity with the number of cycles and reducing the energy penalty of the technology.

  11. Removal of Liquid Leaked into Narrow Channel Using High-Intensity Aerial Ultrasonic Waves

    Science.gov (United States)

    Ito, Youichi; Kotani, Masayuki

    2004-05-01

    We tried to remove a liquid leaked into a narrow channel immediately by radiating high-intensity aerial ultrasonic waves (at a frequency of 20 kHz) onto the liquid to atomize and disperse it into the atmosphere. Channels of 0.3 to 2 mm width and 1 to 10 mm depth with and without a bottom were used. The results of experiments showed that an ultrasonic radiation of 170 dB or more could remove a liquid in each of the channels immediately, by atomizing and dispersing it. The processes of atomization and dispersion of the liquid in each channel without a bottom largely varied, depending on the channel width and depth as well as the ultrasonic radiation intensity.

  12. Lighting up the Christmas tree: high-intensity laser interactions with a nano-structured target

    CERN Document Server

    Gonoskov, A; Ilderton, A; Mackenroth, F; Marklund, M

    2014-01-01

    We perform a numerical study of the interaction of a high-intensity laser pulse with a nano-structured target. In particular, we study a target where the nano-structuring increases the absorption rate as compared to the flat target case. The transport of electrons within the target, and in particular in the nano-structure, is analysed. It is shown that it is indeed possible, using a terawatt class laser, to light up a nano-scale Christmas tree. Due to the form of the tree we achieve very strong edge fields, in particular at the top where the star is located. Such edge fields, as here located at ion rich spots, makes strong acceleration gradients possible. It also results in a nice, warm glow suitable for the holiday season.

  13. Laser Stripping via a Broad Stark State for a High-Intensity Proton Ring

    CERN Document Server

    Yamane, I; Takayama, K; Yamane, Isao; Suzuki, Toshikazu; Takayama, Ken

    2002-01-01

    A new type of charge-exchange injection scheme for high-intensity proton rings that use a laser beam and an undulator magnet is proposed. The elementary stripping process is resonant photoionization via a broad Stark state formed by the Stark effect at an energy level near the peak of the potential barrier. The method used to estimate the parameters of the necessary laser beam and magnetic field is described. As an application to an actual accelerator, a laser stripping system using a high-finesse Fabry-Perot resonator and an undulator is proposed. An estimation of the photon loss due to the pumping-up of H$^0$ atoms, tunability of the system and the emittance growth due to stripping in the undulator magnet is also given.

  14. Low- Versus High-Intensity Plyometric Exercise During Rehabilitation After Anterior Cruciate Ligament Reconstruction.

    Science.gov (United States)

    Chmielewski, Terese L; George, Steven Z; Tillman, Susan M; Moser, Michael W; Lentz, Trevor A; Indelicato, Peter A; Trumble, Troy N; Shuster, Jonathan J; Cicuttini, Flavia M; Leeuwenburgh, Christiaan

    2016-03-01

    Plyometric exercise is used during rehabilitation after anterior cruciate ligament (ACL) reconstruction to facilitate the return to sports participation. However, clinical outcomes have not been examined, and high loads on the lower extremity could be detrimental to knee articular cartilage. To compare the immediate effect of low- and high-intensity plyometric exercise during rehabilitation after ACL reconstruction on knee function, articular cartilage metabolism, and other clinically relevant measures. Randomized controlled trial; Level of evidence, 2. Twenty-four patients who underwent unilateral ACL reconstruction (mean, 14.3 weeks after surgery; range, 12.1-17.7 weeks) were assigned to 8 weeks (16 visits) of low- or high-intensity plyometric exercise consisting of running, jumping, and agility activities. Groups were distinguished by the expected magnitude of vertical ground-reaction forces. Testing was conducted before and after the intervention. Primary outcomes were self-reported knee function (International Knee Documentation Committee [IKDC] subjective knee form) and a biomarker of articular cartilage degradation (urine concentrations of crosslinked C-telopeptide fragments of type II collagen [uCTX-II]). Secondary outcomes included additional biomarkers of articular cartilage metabolism (urinary concentrations of the neoepitope of type II collagen cleavage at the C-terminal three-quarter-length fragment [uC2C], serum concentrations of the C-terminal propeptide of newly formed type II collagen [sCPII]) and inflammation (tumor necrosis factor-α), functional performance (maximal vertical jump and single-legged hop), knee impairments (anterior knee laxity, average knee pain intensity, normalized quadriceps strength, quadriceps symmetry index), and psychosocial status (kinesiophobia, knee activity self-efficacy, pain catastrophizing). The change in each measure was compared between groups. Values before and after the intervention were compared with the groups

  15. Vortex Dynamics and Shear-Layer Instability in High-Intensity Cyclotrons

    Science.gov (United States)

    Cerfon, Antoine J.

    2016-04-01

    We show that the space-charge dynamics of high-intensity beams in the plane perpendicular to the magnetic field in cyclotrons is described by the two-dimensional Euler equations for an incompressible fluid. This analogy with fluid dynamics gives a unified and intuitive framework to explain the beam spiraling and beam breakup behavior observed in experiments and in simulations. Specifically, we demonstrate that beam breakup is the result of a classical instability occurring in fluids subject to a sheared flow. We give scaling laws for the instability and predict the nonlinear evolution of beams subject to it. Our work suggests that cyclotrons may be uniquely suited for the experimental study of shear layers and vortex distributions that are not achievable in Penning-Malmberg traps.

  16. Erythrocytes and microbubble contrast agents, improve the therapeutic efficiency of high intensity focused ultrasound

    Science.gov (United States)

    Takegami, Kenji; Kaneko, Yukio; Watanabe, Toshiaki; Maruyama, Toshiyuki; Matsumoto, Yoichiro; Nagawa, Hirokazu

    2005-03-01

    Erythrocytes, an well as Levovist microbubble contrast agent, enhance the heating effect of high intensity focused ultrasound (HIFU) and increase the coagulation volume produced by HIFU irradiation. In vitro experiments used human plasma with various concentrations of human erythrocytes in combination with or without Levovist. In vivo experiments used eight Japan white rabbits with three levels of anaemia. Using a 2.17 MHz transducer, HIFU was applied for 60 seconds, and the temperature rise and the volume of coagulation necrosis was evaluated. There was a significant correlation between the HIFU-induced temperature rise and hematocrit, with a correlation coefficient of 0.998 (p=0.0001). Although the temperature rise was smaller at low hematocrit, it was significantly increased by adding Levovist to the suspension (panaemia group was significantly increased by using Levovist (p<0.01).

  17. Laser-enhanced high-intensity focused ultrasound heating in an in vivo small animal model

    Science.gov (United States)

    Jo, Janggun; Yang, Xinmai

    2016-11-01

    The enhanced heating effect during the combination of high-intensity focused ultrasound (HIFU) and low-optical-fluence laser illumination was investigated by using an in vivo murine animal model. The thighs of murine animals were synergistically irradiated by HIFU and pulsed nano-second laser light. The temperature increases in the target region were measured by a thermocouple under different HIFU pressures, which were 6.2, 7.9, and 9.8 MPa, in combination with 20 mJ/cm2 laser exposures at 532 nm wavelength. In comparison with conventional laser therapies, the laser fluence used here is at least one order of magnitude lower. The results showed that laser illumination could enhance temperature during HIFU applications. Additionally, cavitation activity was enhanced when laser and HIFU irradiation were concurrently used. Further, a theoretical simulation showed that the inertial cavitation threshold was indeed decreased when laser and HIFU irradiation were utilized concurrently.

  18. OFI rare-gas excimer amplifier for high-intensity VUV pulse generation

    Science.gov (United States)

    Katto, Masahito; Kaku, Masanori; Oda, Kazuyoshi; Kamikihara, Tadashi; Yokotani, Atsushi; Kubodera, Shoichi; Miyanaga, Noriaki; Mima, Kunioki

    2009-02-01

    We have demonstrated an argon excimer vacuum ultraviolet (VUV) amplifier at 126 nm by using the optical-field induced ionization (OFI) of argon. The gain-length product of 5.6 was achieved as a result of the optical feedback inside the amplifier with a VUV mirror. Plasma self-channeling caused by the high-intensity pump laser was simultaneously observed when the maximum gain-length product was observed. We have also optimized the output power of a subpicosecond VUV seed beam at 126 nm produced in low-pressure rare-gases as a result of the seventh harmonic nonlinear wavelength conversion of a Ti:Sapphire laser at 882 nm.

  19. Vacuum ultraviolet argon excimer laser at 126 nm excited by a high intensity laser

    Science.gov (United States)

    Kaku, Masanori; Harano, Shinya; Katto, Masahito; Kubodera, Shoichi

    2010-09-01

    We have observed the optical amplification of the Ar2* excimer at 126 nm pumped by optical-field-induced ionization (OFI) caused by an infrared high-intensity laser. We have evaluated similar small signal gain coefficients of approximately 1.0 cm-1 in two different experiments, where OFI Ar plasmas as gain media were produced in free space filled with Ar and inside an Ar-filled hollow fiber. This indicates that the function of a hollow fiber was to guide the infrared excitation laser and VUV Ar2* emissions, and not to regulate the OFI plasma. Despite the gain coefficient value at 126 nm, the laser oscillation has not been observed. This was limited by the optical quality of available state-of-the-art vacuum ultraviolet optics.

  20. Cardiorespiratory responses and reduced apneic time to cold-water face immersion after high intensity exercise.

    Science.gov (United States)

    Konstantinidou, Sylvia; Soultanakis, Helen

    2016-01-01

    Apnea after exercise may evoke a neurally mediated conflict that may affect apneic time and create a cardiovascular strain. The physiological responses, induced by apnea with face immersion in cold water (10 °C), after a 3-min exercise bout, at 85% of VO2max,were examined in 10 swimmers. A pre-selected 40-s apnea, completed after rest (AAR), could not be met after exercise (AAE), and was terminated with an agonal gasp reflex, and a reduction of apneic time, by 75%. Bradycardia was evident with immersion after both, 40-s of AAR and after AAE (Pexercise without apnea was not equally elevated. The activation of neurally opposing functions as those elicited by the diving reflex after high intensity exercise may create an autonomic conflict possibly related to oxygen-conserving reflexes stimulated by the trigeminal nerve, and those elicited by exercise.

  1. Left-Right Symmetric Models at the High-Intensity Frontier

    CERN Document Server

    Castillo-Felisola, Oscar; Helo, Juan C; Kovalenko, Sergey G; Ortiz, Sebastian E

    2015-01-01

    We study constraints on Left-Right Symmetric models from searches of semileptonic decays of $D$, $D_{s}$, $B$ mesons, mediated by heavy neutrinos $N$ with masses $m_N\\sim $ GeV that go on their mass shell leading to a resonant enhancement of the rates. Using these processes we examine, as a function of $m_N$ and $M_{W_R}$, the physics reach of the recently proposed high-intensity beam dump experiment SHiP, which is expected to produce a large sample of $D_s$ mesons. We compare these results with the corresponding reach of neutrinoless double beta decay experiments, as well as like-sign dilepton searches with displaced vertices at the LHC. We conclude that the SHiP experiment has clear advantages in probing the Left-Right Symmetric models for heavy neutrinos in the GeV mass range.

  2. Design of a high-intensity RFQ for a possible LHC laser ion source

    CERN Document Server

    Hanke, K

    2002-01-01

    We have designed a 100 MHz RFQ to accelerate Pb25+ ions from 9.6 keV/u to 250 keV/u for the LHC ion program. We assume an input beam from a laser ion source with a total beam current of 90 mA, out of which 9 mA is Pb25+. The main challenge of the design is to match the tight longitudinal acceptance of the downstream Interdigital H structure while dealing with a high intensity beam composed of a variety of charge states. In this paper, we present a baseline setup optimized for nominal conditions, and show the sensitivity of the RFQ performance to varying input beam characteristics and rf parameters. Further studies will cover the compatibility of this design with an upgraded ECR source under investigation at CERN.

  3. Preoperative high-intensity training in frail old patients undergoing pulmonary resection for NSCLC

    Directory of Open Access Journals (Sweden)

    Salvi Rosario

    2016-01-01

    Full Text Available Thoracic surgery remains the better therapeutic option for non-small cell lung cancer patients that are diagnosed in early stage disease. Preoperative lung function assessment includes respiratory function tests (RFT and cardio-pulmonary exercise testing (CPET. Vo2 peak, FEV1 and DLCO as well as recognition of performance status, presence of co-morbidities, frailty indexes, and age predict the potential impact of surgical resection on patient health status and survival risk. In this study we have retrospectively assessed the benefit of a high-intensity preoperative pulmonary rehabilitation program (PRP in 14 patients with underlying lung function impairment prior to surgery. Amongst these, three patients candidate to surgical resection exhibited severe functional impairment associated with high score of frailty according CHS and SOF index, resulting in a substantial mortality risk.

  4. [High-intensity focused ultrasound and prostate cancer: technology, state of the art and future].

    Science.gov (United States)

    Vespasiani, G; Asimakopoulos, A D; Finazzi Agrò, E; Virgili, G

    2008-01-01

    BACKGROUND. The potential applications of the high-intensity focused ultrasound (HIFU) as a minimally invasive therapy of the localized prostate cancer explain the growing interest of the urologic community towards this technique. HIFU has been assessed for its role in the treatment of localized prostate cancer in patients who otherwise would not have benefited from surgery, and in local recurrences after radiation failure. Methods. Relevant information on HIFU treatment was identified through a literature search of published studies. RESULTS. High biochemical efficacy, excellent tumor local control and favorable mid- and long-term oncological data with a low morbidity rate have been shown in many series of patients. CONCLUSIONS. Although HIFU is a recent and emerging technology, it has been well studied and developed to a point that HIFU will undoubtedly be an effective alternative to radiation therapy.

  5. A Rectourethral Fistula due to Transrectal High-Intensity Focused Ultrasound Treatment: Diagnosis and Management

    Directory of Open Access Journals (Sweden)

    Valeria Fiaschetti

    2012-01-01

    Full Text Available Colovesical fistula (CVF is an abnormal connection between the enteric and the urinary systems. The rectourethral fistula (RUF is a possible but extremely rare complication of treatment of prostate cancer with “transrectal High-Intensity Focused Ultrasound (HIFU treatment.” We present a case of CVF due to HIFU treatment of recurrent prostate cancer. The case was assessed with cystography completed with a pelvic CT scan—with MPR, MIP, and VR reconstruction—before emptying the bladder. Since the CT scan confirmed that the fistula involved solely the urethra and excluded even a minimal involvement of the bladder, it was possible to employ a conservative treatment by positioning a Foley catheter of monthly duration, in order to allow the urethra to rest. Still today, after 6 months, the patient is in a good clinical condition and has not shown yet signs of a recurrence of the fistula.

  6. High-intensity laser-accelerated ion beam produced from cryogenic micro-jet target

    Science.gov (United States)

    Gauthier, M.; Kim, J. B.; Curry, C. B.; Aurand, B.; Gamboa, E. J.; Göde, S.; Goyon, C.; Hazi, A.; Kerr, S.; Pak, A.; Propp, A.; Ramakrishna, B.; Ruby, J.; Willi, O.; Williams, G. J.; Rödel, C.; Glenzer, S. H.

    2016-11-01

    We report on the successful operation of a newly developed cryogenic jet target at high intensity laser-irradiation. Using the frequency-doubled Titan short pulse laser system at Jupiter Laser Facility, Lawrence Livermore National Laboratory, we demonstrate the generation of a pure proton beam a with maximum energy of 2 MeV. Furthermore, we record a quasi-monoenergetic peak at 1.1 MeV in the proton spectrum emitted in the laser forward direction suggesting an alternative acceleration mechanism. Using a solid-density mixed hydrogen-deuterium target, we are also able to produce pure proton-deuteron ion beams. With its high purity, limited size, near-critical density, and high-repetition rate capability, this target is promising for future applications.

  7. The Fermilab Main Injector: high intensity operation and beam loss control

    CERN Document Server

    Brown, Bruce C; Capista, David; Chou, Weiren; Kourbanis, Ioanis; Morris, Denton K; Seiya, Kiyomi; Wu, Guan Hong; Yang, Ming-Jen

    2013-01-01

    From 2005 through 2012, the Fermilab Main Injector provided intense beams of 120 GeV protons to produce neutrino beams and antiprotons. Hardware improvements in conjunction with improved diagnostics allowed the system to reach sustained operation at ~400 kW beam power. Transmission was very high except for beam lost at or near the 8 GeV injection energy where 95% beam transmission results in about 1.5 kW of beam loss. By minimizing and localizing loss, residual radiation levels fell while beam power was doubled. Lost beam was directed to either the collimation system or to the beam abort. Critical apertures were increased while improved instrumentation allowed optimal use of available apertures. We will summarize the improvements required to achieve high intensity, the impact of various loss control tools and the status and trends in residual radiation in the Main Injector.

  8. Autonomic cardiovascular modulation in masters and young cyclists following high-intensity interval training.

    Science.gov (United States)

    Borges, Nattai R; Reaburn, Peter R; Doering, Thomas M; Argus, Christos K; Driller, Matthew W

    2017-04-01

    This study aimed at examining the autonomic cardiovascular modulation in well-trained masters and young cyclists following high-intensity interval training (HIT). Nine masters (age 55.6 ± 5.0 years) and eight young cyclists (age 25.9 ± 3.0 years) completed a HIT protocol of 6 x 30 sec at 175% of peak power output, with 4.5-min' rest between efforts. Immediately following HIT, heart rate and R-R intervals were monitored for 30-min during passive supine recovery. Autonomic modulation was examined by i) heart rate recovery in the first 60-sec of recovery (HRR60); ii) the time constant of the 30-min heart rate recovery curve (HRRτ); iii) the time course of the root mean square for successive 30-sec R-R interval (RMSSD30); and iv) time and frequency domain analyses of subsequent 5-min R-R interval segments. No significant between-group differences were observed for HRR60 (P = 0.096) or HRRτ (P = 0.617). However, a significant interaction effect was found for RMSSD30 (P = 0.021), with the master cyclists showing higher RMSSD30 values following HIT. Similar results were observed in the time and frequency domain analyses with significant interaction effects found for the natural logarithm of the RMSSD (P = 0.008), normalised low-frequency power (P = 0.016) and natural logarithm of high-frequency power (P = 0.012). Following high-intensity interval training, master cyclists demonstrated greater post-exercise parasympathetic reactivation compared to young cyclists, indicating that physical training at older ages has significant effects on autonomic function.

  9. A novel image-guided high-intensity focused ultrasound system for tumor treatment

    Science.gov (United States)

    Wu, Zhiqiang; Wu, Puwei; Chen, Bojie; Guan, Jian; Huang, Zheng

    2004-07-01

    A novel ultrasonography-guided high intensity focused ultrasound (HIFU) system (FS-100; Force Electronics Co. Ltd, Chongqing, China) was developed for non-invasive thermal ablation of tumor. The proprietary therapy delivery system is an integration of the digital image progressing, automatic control and the high intensity focused ultrasound thermal ablation devices. The therapeutic ultrasound probe (φ = 240 mm) consists of eight circular HIFU transducers with a curved surface of a diameter of 60 mm. Dual focused beams generated from the probe were used in this system for thermal delivery. The probe has the maximal resonance frequency of 1 MHz, a maximal treatment depth of 160 mm and focal spot diameter of 3 mm. The maximal intensity at the focal spot is 10,000 W/cm2. The imaging and HIFU components are located on top of the device, therefore, the focused ultrasound beams can be delivered to the patient in a supine position. The motion, targeting and localization of the probe are controlled by a PMAC-PC motion controller and an 8-independent-axis mechanical device. The linear motion error of the probe localization is <= 0.1 mm. The ultrasonographic image information is used for treatment planning and therapeutic interventions, such as target definition and registration, visualization of the three-dimensional anatomy of desired target(s), automatic positioning the thermal beams on targets, controlling thermal delivery, and rapid evaluation of target response post-treatment. The preclinical experimental results will be presented. The safety, feasibility and effectiveness of this novel HIFU system will be tested.

  10. The effect of warm-up on high-intensity, intermittent running using nonmotorized treadmill ergometry.

    Science.gov (United States)

    Brown, Peter I; Hughes, Michael G; Tong, Richard J

    2008-05-01

    The aim of this study was to investigate the effect of previous warming on high-intensity intermittent running using nonmotorized treadmill ergometry. Ten male soccer players completed a repeated sprint test (10 x 6-second sprints with 34-second recovery) on a nonmotorized treadmill preceded by an active warm-up (10 minutes of running: 70% VO2max; mean core temperature (Tc) 37.8 +/- 0.2 degrees C), a passive warm-up (hot water submersion: 40.1 +/- 0.2 degrees C until Tc reached that of the active warm-up; 10 minutes +/- 23 seconds), or no warm-up (control). All warm-up conditions were followed by a 10-minute static recovery period with no stretching permitted. After the 10-minute rest period, Tc was higher before exercise in the passive trial (38.0 +/- 0.2 degrees C) compared to the active (37.7 +/- 0.4 degrees C) and control trials (37.2 +/- 0.2 degrees C; p pre-exercise oxygen consumption and blood lactate concentration; however, heart rate was greater in the active trial (p 0.05), although both were greater than the control. The percentage of decrement in performance fatigue was similar between all conditions (active, 3.4 +/- 1.3%; passive, 4.0 +/- 2.0%; and control, 3.7 +/- 2.4%). We conclude that there is no difference in high-intensity intermittent running performance when preceded by an active or passive warm-up when matched for post-warm-up Tc. However, repeated sprinting ability is significantly improved after both active and passive warm-ups compared to no warm-up.

  11. Sleep monitoring of a six-day microcycle in strength and high-intensity training.

    Science.gov (United States)

    Kölling, Sarah; Wiewelhove, Thimo; Raeder, Christian; Endler, Stefan; Ferrauti, Alexander; Meyer, Tim; Kellmann, Michael

    2016-08-01

    This study examined the effect of microcycles in eccentric strength and high-intensity interval training (HIT) on sleep parameters and subjective ratings. Forty-two well-trained athletes (mean age 23.2 ± 2.4 years) were either assigned to the strength (n = 21; mean age 23.6 ± 2.1 years) or HIT (n = 21; mean age 22.8 ± 2.6 years) protocol. Sleep monitoring was conducted with multi-sensor actigraphy (SenseWear Armband™, Bodymedia, Pittsburg, PA, USA) and sleep log for 14 days. After a five-day baseline phase, participants completed either eccentric accented strength or high-intensity interval training for six days, with two training sessions per day. This training phase was divided into two halves (part 1 and 2) for statistical analyses. A three-day post phase concluded the monitoring. The Recovery-Stress Questionnaire for Athletes was applied at baseline, end of part 2, and at the last post-day. Mood ratings were decreased during training, but returned to baseline values afterwards in both groups. Sleep parameters in the strength group remained constant over the entire process. The HIT group showed trends of unfavourable sleep during the training phase (e.g., objective sleep efficiency at part 2: mean = 83.6 ± 7.8%, F3,60 = 2.57, P = 0.06, [Formula: see text] = 0.114) and subjective improvements during the post phase for awakenings (F3,60 = 2.96, P = 0.04, [Formula: see text] = 0.129) and restfulness of sleep (F3,60 = 9.21, P strength training, and sufficient sleep time should be emphasised and monitored.

  12. High-intensity light-emitting diode vs fluorescent tubes for intensive phototherapy in neonates.

    Science.gov (United States)

    Sherbiny, Hanan S; Youssef, Doaa M; Sherbini, Ahmad S; El-Behedy, Rabab; Sherief, Laila M

    2016-05-01

    Special blue fluorescent tubes are recommended by the American Academy of Pediatrics (AAP) as the most effective light source for lowering serum bilirubin. A high-intensity light-emitting diode ('super LED') could render intensive phototherapy more effective than the above conventional methods. This study compared the efficacy and safety of a high-intensity light-emitting diode bed vs conventional intensive phototherapy with triple fluorescent tube units as a rescue treatment for severe unconjugated neonatal hyperbilirubinaemia. This was a randomised, prospective trial. Two hundred jaundiced neonates ≥ 35 weeks gestation who met the criteria for intensive phototherapy as per AAP guidelines were randomly assigned to be treated either with triple fluorescent tube units (group 1, n = 100) or a super LED bed (group 2, n = 100). The outcome was the avoidance of exchange transfusion by successful control of hyperbilirubinaemia. Statistically significant higher success rates of intensive phototherapy were achieved among neonates treated with super LED (group 2) than in those treated conventionally (group 1) (87% vs 64%, P = 0.003). Significantly higher 'bilirubin decline' rates were reported in both haemolytic and non-haemolytic subgroups treated with the super LED bed compared with a similar sub-population in the conventionally treated group. Comparable numbers of neonates in both groups developed rebound jaundice (8% vs 10% of groups 1 and 2, respectively). Side-effects were mild in both groups, but higher rates of hyperthermia (12% vs 0%, P = 0.03), dehydration (8% vs 2%, P = 0.26) and skin rash (39% vs 1%, P = 0.002) were reported in the fluorescent tubes-treated group compared with the LED group. Super LED is a safe rescue treatment for severe neonatal hyperbilirubinaemia, and its implementation may reduce the need for exchange transfusion.

  13. Central and peripheral adjustments during high-intensity exercise following cold water immersion.

    Science.gov (United States)

    Stanley, Jamie; Peake, Jonathan M; Coombes, Jeff S; Buchheit, Martin

    2014-01-01

    We investigated the acute effects of cold water immersion (CWI) or passive recovery (PAS) on physiological responses during high-intensity interval training (HIIT). In a crossover design, 14 cyclists completed 2 HIIT sessions (HIIT1 and HIIT2) separated by 30 min. Between HIIT sessions, they stood in cold water (10 °C) up to their umbilicus, or at room temperature (27 °C) for 5 min. The natural logarithm of square-root of mean squared differences of successive R-R intervals (ln rMSSD) was assessed pre- and post-HIIT1 and HIIT2. Stroke volume (SV), cardiac output (Q), O2 uptake (VO2), total muscle hemoglobin (t Hb) and oxygenation of the vastus lateralis were recorded (using near infrared spectroscopy); heart rate, Q, and VO2 on-kinetics (i.e., mean response time, MRT), muscle de-oxygenation rate, and anaerobic contribution to exercise were calculated for HIIT1 and HIIT2. ln rMSSD was likely higher [between-trial difference (90% confidence interval) [+13.2% (3.3; 24.0)] after CWI compared with PAS. CWI also likely increased SV [+5.9% (-0.1; 12.1)], possibly increased Q [+4.4% (-1.0; 10.3)], possibly slowed Q MRT [+18.3% (-4.1; 46.0)], very likely slowed VO2 MRT [+16.5% (5.8; 28.4)], and likely increased the anaerobic contribution to exercise [+9.7% (-1.7; 22.5)]. CWI between HIIT slowed VO2 on-kinetics, leading to increased anaerobic contribution during HIIT2. This detrimental effect of CWI was likely related to peripheral adjustments, because the slowing of VO2 on-kinetics was twofold greater than that of central delivery of O2 (i.e., Q). CWI has detrimental effects on high-intensity aerobic exercise performance that persist for ≥ 45 min.

  14. Optical Frequency Optimization of a High Intensity Laser Power Beaming System Utilizing VMJ Photovoltaic Cells

    Science.gov (United States)

    Raible, Daniel E.; Dinca, Dragos; Nayfeh, Taysir H.

    2012-01-01

    An effective form of wireless power transmission (WPT) has been developed to enable extended mission durations, increased coverage and added capabilities for both space and terrestrial applications that may benefit from optically delivered electrical energy. The high intensity laser power beaming (HILPB) system enables long range optical 'refueling" of electric platforms such as micro unmanned aerial vehicles (MUAV), airships, robotic exploration missions and spacecraft platforms. To further advance the HILPB technology, the focus of this investigation is to determine the optimal laser wavelength to be used with the HILPB receiver, which utilizes vertical multi-junction (VMJ) photovoltaic cells. Frequency optimization of the laser system is necessary in order to maximize the conversion efficiency at continuous high intensities, and thus increase the delivered power density of the HILPB system. Initial spectral characterizations of the device performed at the NASA Glenn Research Center (GRC) indicate the approximate range of peak optical-to-electrical conversion efficiencies, but these data sets represent transient conditions under lower levels of illumination. Extending these results to high levels of steady state illumination, with attention given to the compatibility of available commercial off-the-shelf semiconductor laser sources and atmospheric transmission constraints is the primary focus of this paper. Experimental hardware results utilizing high power continuous wave (CW) semiconductor lasers at four different operational frequencies near the indicated band gap of the photovoltaic VMJ cells are presented and discussed. In addition, the highest receiver power density achieved to date is demonstrated using a single photovoltaic VMJ cell, which provided an exceptionally high electrical output of 13.6 W/sq cm at an optical-to-electrical conversion efficiency of 24 percent. These results are very promising and scalable, as a potential 1.0 sq m HILPB receiver of

  15. High-intensity statin therapy alters the natural history of diabetic coronary atherosclerosis: insights from SATURN.

    Science.gov (United States)

    Stegman, Brian; Puri, Rishi; Cho, Leslie; Shao, Mingyuan; Ballantyne, Christie M; Barter, Phillip J; Chapman, M John; Erbel, Raimund; Libby, Peter; Raichlen, Joel S; Uno, Kiyoko; Kataoka, Yu; Nissen, Steven E; Nicholls, Stephen J

    2014-11-01

    Although statins can induce coronary atheroma regression, this benefit has yet to be demonstrated in diabetic individuals. We tested the hypothesis that high-intensity statin therapy may promote coronary atheroma regression in patients with diabetes. The Study of Coronary Atheroma by Intravascular Ultrasound: Effect of Rosuvastatin Versus Atorvastatin (SATURN) used serial intravascular ultrasound measures of coronary atheroma volume in patients treated with rosuvastatin 40 mg or atorvastatin 80 mg for 24 months. This analysis compared changes in biochemistry and coronary percent atheroma volume (PAV) in patients with (n = 159) and without (n = 880) diabetes. At baseline, patients with diabetes had lower LDL cholesterol (LDL-C) and HDL cholesterol (HDL-C) levels but higher triglyceride and CRP levels compared with patients without diabetes. At follow-up, diabetic patients had lower levels of LDL-C (61.0 ± 20.5 vs. 66.4 ± 22.9 mg/dL, P = 0.01) and HDL-C (46.3 ± 10.6 vs. 49.9 ± 12.0 mg/dL, P 70 mg/dL (-0.31 ± 0.23 vs. -1.01 ± 0.21%, P = 0.03) but similar when LDL-C levels were ≤70 mg/dL (-1.09 ± 0.16 vs. -1.24 ± 0.16%, P = 0.50). High-intensity statin therapy alters the progressive nature of diabetic coronary atherosclerosis, yielding regression of disease in diabetic and nondiabetic patients. © 2014 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  16. Extremely short duration high intensity interval training substantially improves insulin action in young healthy males

    Directory of Open Access Journals (Sweden)

    Cottrell Greg

    2009-01-01

    Full Text Available Abstract Background Traditional high volume aerobic exercise training reduces cardiovascular and metabolic disease risk but involves a substantial time commitment. Extremely low volume high-intensity interval training (HIT has recently been demonstrated to produce improvements to aerobic function, but it is unknown whether HIT has the capacity to improve insulin action and hence glycemic control. Methods Sixteen young men (age: 21 ± 2 y; BMI: 23.7 ± 3.1 kg·m-2; VO2peak: 48 ± 9 ml·kg-1·min-1 performed 2 weeks of supervised HIT comprising of a total of 15 min of exercise (6 sessions; 4–6 × 30-s cycle sprints per session. Aerobic performance (250-kJ self-paced cycling time trial, and glucose, insulin and NEFA responses to a 75-g oral glucose load (oral glucose tolerance test; OGTT were determined before and after training. Results Following 2 weeks of HIT, the area under the plasma glucose, insulin and NEFA concentration-time curves were all reduced (12%, 37%, 26% respectively, all P -1, P = 0.058. Insulin sensitivity, as measured by the Cederholm index, was improved by 23% (P Conclusion The efficacy of a high intensity exercise protocol, involving only ~250 kcal of work each week, to substantially improve insulin action in young sedentary subjects is remarkable. This novel time-efficient training paradigm can be used as a strategy to reduce metabolic risk factors in young and middle aged sedentary populations who otherwise would not adhere to time consuming traditional aerobic exercise regimes.

  17. Enjoyment of high-intensity interval training in an overweight/obese cohort: a short report.

    Science.gov (United States)

    Smith-Ryan, Abbie E

    2017-01-01

    Exercise enjoyment has been shown to be important for adherence. Minimal data exist on enjoyment of intense exercise, especially in clinical populations. The purpose of this study was to evaluate enjoyment levels of overweight and obese subjects undergoing 3 weeks of high-intensity interval training. Forty-two generally healthy overweight and obese men and women (body mass index = 30·8 ± 4·8 kg × m(-2) ) volunteered for this study. Exercise enjoyment was quantified using the Exercise Enjoyment Scale before and after each of nine total interval training sessions, over a three-week period. Heart rate and ratings of perceived exertion (RPE) were measured at the end of each interval and training session. There were no significant differences in enjoyment between training groups (P > 0·05). Exercise enjoyment improved significantly over the three-week training phase (P high to begin training: mean ± SD: 4·2 ± 1·0 out of a 7 point scale. Heart rate and RPE were significantly reduced (P training (day 9). High-intensity interval training may be an enjoyable form of exercise for overweight and obese men and women. Enjoyment levels may continue to increase following initial introduction to this type of training. Due to the small time demand and high enjoyment, interval training may be an effective exercise approach in a sedentary population. © 2015 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  18. Light-intensity and high-intensity interval training improve cardiometabolic health in rats.

    Science.gov (United States)

    Batacan, Romeo B; Duncan, Mitch J; Dalbo, Vincent J; Connolly, Kylie J; Fenning, Andrew S

    2016-09-01

    Physical activity has the potential to reduce cardiometabolic risk factors but evaluation of different intensities of physical activity and the mechanisms behind their health effects still need to be fully established. This study examined the effects of sedentary behaviour, light-intensity training, and high-intensity interval training on biometric indices, glucose and lipid metabolism, inflammatory and oxidative stress markers, and vascular and cardiac function in adult rats. Rats (12 weeks old) were randomly assigned to 1 of 4 groups: control (CTL; no exercise), sedentary (SED; no exercise and housed in small cages to reduce activity), light-intensity trained (LIT; four 30-min exercise bouts/day at 8 m/min separated by 2-h rest period, 5 days/week), and high-intensity interval trained (HIIT, four 2.5-min work bouts/day at 50 m/min separated by 3-min rest periods, 5 days/week). After 12 weeks of intervention, SED had greater visceral fat accumulation (p < 0.01) and slower cardiac conduction (p = 0.04) compared with the CTL group. LIT and HIIT demonstrated beneficial changes in body weight, visceral and epididymal fat weight, glucose regulation, low-density lipoprotein cholesterol, total cholesterol, and mesenteric vessel contractile response compared with the CTL group (p < 0.05). LIT had significant improvements in insulin sensitivity and cardiac conduction compared with the CTL and SED groups whilst HIIT had significant improvements in systolic blood pressure and endothelium-independent vasodilation to aorta and mesenteric artery compared with the CTL group (p < 0.05). LIT and HIIT induce health benefits by improving traditional cardiometabolic risk factors. LIT improves cardiac health while HIIT promotes improvements in vascular health.

  19. High-Intensity Training Improves Global and Segmental Strains in Severe Congestive Heart Failure.

    Science.gov (United States)

    Blumberg, Yair; Ertracht, Offir; Gershon, Itai; Bachner-Hinenzon, Noa; Reuveni, Tali; Atar, Shaul

    2017-05-01

    High-intensity training (HIT) is superior to moderate aerobic training (MAT) for improving quality of life in congestive heart failure (CHF) patients. Speckle-tracking echocardiography (STE) has recently been suggested for estimation of left ventricle global and regional function. We evaluated the utility of STE for characterizing differences in cardiac function following MAT or HIT in a CHF rat model. After baseline physiologic assessment, CHF was induced by means of coronary artery ligation in Sprague-Dawley rats. Repeated measurements confirmed the presence of CHF (ejection fraction 52 ± 10%, global circumferential strain (GCS) 10.5 ± 4, and maximal oxygen uptake (V˙O2max) 71 ± 11 mL⋅min(-1)⋅kg(-1); P training protocols: sedentary (SED), MAT, or HIT. After the training period, rats underwent the same measurements and were killed. Training intensity improved V˙O2max (73 ± 13 mL⋅min(-1)⋅kg(-1) in MAT [P  .05 vs baseline]). In addition, strains of specific segments adjacent to the infarct zone regained basal values (P > .05 vs baseline), whereas global cardiac functional parameters as assessed with the use of 2-dimensional echocardiography did not improve. High-intensity exercise training improved function in myocardial segments remote from the scar, which resulted in compensatory cardiac remodeling. This effect is prominent, yet it could be detected only with the use of STE. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. An improved permanent magnet quadrupole design with larger good field region for high intensity proton linacs

    Science.gov (United States)

    Mathew, Jose V.; Rao, S. V. L. S.; Krishnagopal, S.; Singh, P.

    2013-11-01

    The Low Energy High Intensity Proton Accelerator (LEHIPA), being developed at the Bhabha Atomic Research Centre (BARC) will produce a 20 MeV, 30 mA, continuous wave (CW) proton beam. At these low velocities, space-charge forces dominate, and could lead to larger beam sizes and beam halos. Hence in the design of the focusing lattice of the LEHIPA drift tube linac (DTL) using permanent magnet quadrupoles (PMQs), a larger good field region is preferred. Here we study, using the two dimensional (2D) and three dimensional (3D) simulation codes PANDIRA and RADIA, four different types of cylindrical PMQ designs: 16-segment trapezoidal Halbach configuration, bullet-nosed geometry and 8- and 16-segment rectangular geometries. The trapezoidal Halbach geometry is used in a variety of accelerators since it provides very high field gradients in small bores, while the bullet-nosed geometry, which is a combination of the trapezoidal and rectangular designs, is used in some DTLs. This study shows that a larger good field region is possible in the 16-segment rectangular design as compared to the Halbach and bullet-nosed designs, making it more attractive for high-intensity proton linacs. An improvement in good-field region by ˜16% over the Halbach design is obtained in the optimized 16-segment rectangular design, although the field gradient is lower by ˜20%. Tolerance studies show that the rectangular segment PMQ design is substantially less sensitive to the easy axis orientation errors and hence will be a better choice for DTLs.

  1. Time course of strength adaptations following high-intensity resistance training in individuals with multiple sclerosis.

    Science.gov (United States)

    Manca, A; Dvir, Z; Dragone, D; Mureddu, G; Bua, G; Deriu, Franca

    2017-04-01

    No evidence exists regarding the time course and clinical relevance of muscle strength improvements following resistance training in people with multiple sclerosis (PwMS). The purpose of this study was to investigate the temporal course and the clinical meaningfulness of the changes in strength induced by high-intensity resistance training and whether these changes impact on muscle endurance to fatigue and functional outcomes. PwMS with predominantly unilateral hyposthenia of the ankle dorsiflexors underwent a 6-week isokinetic training of the more affected ankle dorsiflexion muscles. Maximal strength was measured at baseline, during the training on a weekly basis, at the end of the intervention (POST) and at the 12-week follow-up. Muscle endurance to fatigue, mobility and walking outcomes were assessed at baseline, POST and follow-up. Reproducibility and responsiveness analyses were performed. Significant gains in muscle strength were already detected after 3 weeks of training with no further improvements in the following weeks. These improvements exceeded the cutoff values for relevant changes and were also positively correlated to improved muscle endurance to fatigue and mobility measures. None of the observed changes in muscle performance and functional outcomes was retained at the follow-up. Preliminary evidence showed that 3 weeks of high-intensity resistance training induces consistent and meaningful improvements in muscle performance of the ankle dorsiflexors in PwMS. These findings may have practical dose-response and cost-effectiveness implications in the management of MS-induced muscle weakness, potentially enhancing the understanding of the response to training exhibited by PwMS. ClinicalTrials.gov identifier NCT02010398; December 2013.

  2. EFFECT OF HIGH-INTENSITY EXERCISE ON ENDOTHELIAL FUNCTION IN PATIENTS WITH T2DM

    Directory of Open Access Journals (Sweden)

    Carlos Alberto da Silva

    2016-04-01

    Full Text Available Introduction: Diabetes mellitus is the most common metabolic disease worldwide. Endothelial dysfunction characteristic of these patients is one of the major risk factors for atherosclerosis. Early diagnosis of endothelial dysfunction is essential for the treatment especially of non-invasive manner, such as flow mediated dilation. Physical exercise is capable of generating beneficial adaptations may improve endothelial function. Objective: Identify the effect of physical exercise, using the clinical technique of ultrasound in the assessment of the endothelial function of patients with metabolic syndrome or type 2 diabetes mellitus. Methods: Thirty-one patients with type 2 diabetes mellitus or metabolic syndrome were studied, with a mean age (± SD of 58±6 years, randomized into three groups. The training was performed for 50 minutes, four times a week. Before and after six weeks of training, subjects performed the endurance test and a study of the endothelial function of the brachial artery by high-resolution ultrasound. Results: After hyperemia, the percentage of arterial diameter was significantly higher for the high-intensity group (HI before = 2.52±2.85mm and after = 31.81±12.21mm; LI before = 3.23±3.52mm and after = 20.61±7.76mm; controls before = 3.56±2.33mm and after = 2.43±2.14mm; p<0.05. Conclusions: The high-intensity aerobic training improved the vasodilatation response-dependent endothelium, recorded by ultrasound, in patients with metabolic syndrome and type 2 diabetes.

  3. Parasitic slow extraction of extremely weak beam from a high-intensity proton rapid cycling synchrotron

    Science.gov (United States)

    Zou, Ye; Tang, Jingyu; Yang, Zheng; Jing, Hantao

    2014-02-01

    This paper proposes a novel method to extract extremely weak beam from a high-intensity proton rapid cycling synchrotron (RCS) in the parasitic mode, while maintaining the normal fast extraction. The usual slow extraction method from a synchrotron by employing third-order resonance cannot be applied in a high-intensity RCS due to a very short flat-top at the extraction energy and the strict control on beam loss. The proposed parasitic slow extraction method moves the beam to scrape a scattering foil prior to the fast beam extraction by employing either a local orbit bump or momentum deviation or their combination, so that the halo part of the beam will be scattered. A part of the scattered particles will be extracted from the RCS and guided to the experimental area. The slow extraction process can last about a few milliseconds before the beam is extracted by the fast extraction system. The method has been applied to the RCS of China Spallation Neutron Source. With 1.6 GeV in the extraction energy, 62.5 μA in the average current and 25 Hz in the repetition rate for the RCS, the proton intensity by the slow extraction method can be up to 2×104 protons per cycle or 5×105 protons per second. The extracted beam has also a good time structure of approximately uniform in a spill which is required for many applications such as detector tests. Detailed studies including the scattering effect in the foil, the local orbit bump by the bump magnets and dispersive orbit bump by modifying the RF pattern, the multi-particle simulations by ORBIT and TURTLE codes, and some technical features for the extraction magnets are presented.

  4. Effects of high-intensity interval training on cardiometabolic risk factors in overweight/obese women.

    Science.gov (United States)

    Smith-Ryan, Abbie E; Trexler, Eric T; Wingfield, Hailee L; Blue, Malia N M

    2016-11-01

    The purpose of this study was to evaluate two practical interval training protocols on cardiorespiratory fitness, lipids and body composition in overweight/obese women. Thirty women (mean ± SD; weight: 88.1 ± 15.9 kg; BMI: 32.0 ± 6.0 kg · m(2)) were randomly assigned to ten 1-min high-intensity intervals (90%VO2 peak, 1 min recovery) or five 2-min high-intensity intervals (80-100% VO2 peak, 1 min recovery) or control. Peak oxygen uptake (VO2 peak), peak power output (PPO), body composition and fasting blood lipids were evaluated before and after 3 weeks of training, completed 3 days per week. Results from ANCOVA analyses demonstrated no significant training group differences for any primary variables (P > 0.05). When training groups were collapsed, 1MIN and 2MIN resulted in a significant increase in PPO (∆18.9 ± 8.5 watts; P = 0.014) and time to exhaustion (∆55.1 ± 16.4 s; P = 0.001); non-significant increase in VO2 peak (∆2.36 ± 1.34 ml · kg(-)(1) · min(-)(1); P = 0.185); and a significant decrease in fat mass (FM) (-∆1.96 ± 0.99 kg; P = 0.011). Short-term interval exercise training may be effective for decreasing FM and improving exercise tolerance in overweight and obese women.

  5. Squeezing the muscle: compression clothing and muscle metabolism during recovery from high intensity exercise.

    Directory of Open Access Journals (Sweden)

    Billy Sperlich

    Full Text Available The purpose of this experiment was to investigate skeletal muscle blood flow and glucose uptake in m. biceps (BF and m. quadriceps femoris (QF 1 during recovery from high intensity cycle exercise, and 2 while wearing a compression short applying ~37 mmHg to the thigh muscles. Blood flow and glucose uptake were measured in the compressed and non-compressed leg of 6 healthy men by using positron emission tomography. At baseline blood flow in QF (P = 0.79 and BF (P = 0.90 did not differ between the compressed and the non-compressed leg. During recovery muscle blood flow was higher compared to baseline in both compressed (P<0.01 and non-compressed QF (P<0.001 but not in compressed (P = 0.41 and non-compressed BF (P = 0.05; effect size = 2.74. During recovery blood flow was lower in compressed QF (P<0.01 but not in BF (P = 0.26 compared to the non-compressed muscles. During baseline and recovery no differences in blood flow were detected between the superficial and deep parts of QF in both, compressed (baseline P = 0.79; recovery P = 0.68 and non-compressed leg (baseline P = 0.64; recovery P = 0.06. During recovery glucose uptake was higher in QF compared to BF in both conditions (P<0.01 with no difference between the compressed and non-compressed thigh. Glucose uptake was higher in the deep compared to the superficial parts of QF (compression leg P = 0.02. These results demonstrate that wearing compression shorts with ~37 mmHg of external pressure reduces blood flow both in the deep and superficial regions of muscle tissue during recovery from high intensity exercise but does not affect glucose uptake in BF and QF.

  6. High intensity single bunch operation with heavy periodic transient beam loading in wide band rf cavities

    Science.gov (United States)

    Tamura, Fumihiko; Hotchi, Hideaki; Schnase, Alexander; Yoshii, Masahito; Yamamoto, Masanobu; Ohmori, Chihiro; Nomura, Masahiro; Toda, Makoto; Shimada, Taihei; Hasegawa, Katsushi; Hara, Keigo

    2015-09-01

    The rapid cycling synchrotron (RCS) in the Japan Proton Accelerator Research Complex (J-PARC) was originally designed to accelerate two high intensity bunches, while some of neutron experiments in the materials and life science experimental facility and a muon experiment using main ring beams require a single bunch operation mode, in which one of the two rf buckets is filled and the other is empty. The beam intensity in the single bunch operation has been limited by longitudinal beam losses due to the rf bucket distortions by the wake voltage of the odd harmonics (h =1 ,3 ,5 ) in the wide band magnetic alloy cavities. We installed an additional rf feedforward system to compensate the wake voltages of the odd harmonics (h =1 ,3 ,5 ). The additional system has a similar structure as the existing feedforward system for the even harmonics (h =2 ,4 ,6 ). We describe the function of the feedforward system for the odd harmonics, the commissioning methodology, and the commissioning results. The longitudinal beam losses during the single bunch acceleration disappeared with feedforward for the odd harmonics. We also confirmed that the beam quality in the single bunch acceleration are similar to that of the normal operation with two bunches. Thus, high intensity single bunch acceleration at the intensity of 2.3 ×1013 protons per bunch has been achieved in the J-PARC RCS. This article is a follow-up of our previous article, Phys. Rev. ST Accel. Beams 14, 051004 (2011). The feedforward system extension for single bunch operation was successful.

  7. EFFECTS OF HIGH-INTENSITY ENDURANCE EXERCISE ON EPIDERMAL BARRIERS AGAINST MICROBIAL INVASION

    Directory of Open Access Journals (Sweden)

    Nobuhiko Eda

    2013-03-01

    Full Text Available For athletes, preventing infectious disease on skin is important. Examination measurement of epidermal barriers could provide valuable information on the risk of skin infections. The aim of this study was to determine the effects of high-intensity endurance exercise on epidermal barriers. Six healthy adult males (age; 22.3 ± 1.6 years performed bicycle exercise at 75%HRmax for 60 min from 18:30 to 19:30. Skin surface samples were measured 18:30 (pre, 19:30 (post, 20:30 (60 min, and 21:30 (120 min. Secretory immunoglobulin A (SIgA and human β-defensin 2 (HBD-2 concentrations were measured using an enzyme-linked immunosorbent assay (ELISA. SIgA concentration at pre was significantly higher than at post, 60 min and 120 min (p < 0.05. HBD-2 concentration at post and 120 min was significantly higher than at pre (p < 0. 05. Moisture content of the stratum corneum was significantly higher at post than at pre, 60 min, and 120 min (p < 0.05. On the chest, moisture content of the stratum corneum was significantly lower at 120 min than at pre (p < 0.05. The number of staphylococci was significantly higher at post than at pre (p < 0.05, and tended to be higher at 60 min than at pre on the chest (p = 0. 08. High-intensity endurance exercise might depress the immune barrier and physical barrier and enhance the risk of skin infection. On the other hand, the biochemical barrier increases after exercise, and our findings suggest that this barrier might supplement the compromised function of other skin barriers.

  8. High-Intensity Interval Training in Patients with Substance Use Disorder

    Directory of Open Access Journals (Sweden)

    Grete Flemmen

    2014-01-01

    Full Text Available Patients with substance use disorder (SUD suffer a higher risk of cardiovascular disease and other lifestyle diseases compared to the general population. High intensity training has been shown to effectively reduce this risk, and therefore we aimed to examine the feasibility and effect of such training in SUD patients in clinical treatment in the present study. 17 males and 7 females (32 ± 8 yr in treatment were randomized to either a training group (TG, treadmill interval training in 4 × 4 minutes at 90–95% of maximal heart rate, 3 days a week for 8 weeks, or a conventional rehabilitation control group (CG. Baseline values for both groups combined at inclusion were 44 ± 8 (males and 34 ± 9 (females mL · min−1 · kg−1, respectively. 9/12 and 7/12 patients completed the TG and CG, respectively. Only the TG significantly improved (15 ± 7% their maximal oxygen consumption (VO2max, from 42.3 ± 7.2 mL · min−1 · kg−1 at pretest to 48.7 ± 9.2 mL · min−1 · kg−1 at posttest. No between-group differences were observed in work economy, and level of insomnia (ISI or anxiety and depression (HAD, but a significant within-group improvement in depression was apparent for the TG. High intensity training was feasible for SUD patients in treatment. This training form should be implemented as a part of the rehabilitation since it, in contrast to the conventional treatment, represents a risk reduction for cardiovascular disease and premature death.

  9. The influence of loading intensity on muscle-tendon unit behavior during maximal knee extensor stretch shortening cycle exercise.

    Science.gov (United States)

    Earp, Jacob E; Newton, Robert U; Cormie, Prue; Blazevich, Anthony J

    2014-01-01

    Tendon stiffness increases as the magnitude and rate of loading increases, according to its viscoelastic properties. Thus, under some loading conditions tendons should become exceptionally stiff and act almost as rigid force transducers. Nonetheless, observations of tendon behavior during multi-joint sprinting and jumping tasks have shown that tendon strain increases whilst muscle strain decreases as the loading intensity increases. The purpose of the current study was to examine the influence of external loading intensity on muscle-tendon unit (MTU) behavior during a high-speed single-joint, stretch-shortening cycle (SSC) knee extension task. Eighteen men (n = 9) and women (n = 9) performed single-leg, maximum intensity SSC knee extensions at loads of 20, 60 and 90% of their one repetition maximum. Vastus lateralis fascicle length (L(f)) and velocity (v(f)) as well as MTU (L(MTU)) and tendinous tissue (L(t)) length were measured using high-speed ultrasonography (96 Hz). Patellar tendon force (F(t)) and rate of force development (RFDt) were estimated using inverse dynamics. Results showed that as loading intensity increased, concentric joint velocity and shortening v f decreased whilst F t and RFDt increased, but no significant differences were observed in eccentric joint velocity or peak L(MTU) or L(f). In addition, the tendon lengthened significantly less at the end of the eccentric phase at heavier loads. This is the first observation that tendon strain decreases significantly during a SSC movement as loading intensity increases in vivo, resulting in a shift in the tendon acting as a power amplifier at light loads to a more rigid force transducer at heavy loads.

  10. Function of a large biarticular hip and knee extensor during walking and running in guinea fowl (Numida meleagris).

    Science.gov (United States)

    Carr, Jennifer A; Ellerby, David J; Marsh, Richard L

    2011-10-15

    Physiological and anatomical evidence suggests that in birds the iliotibialis lateralis pars postacetabularis (ILPO) is functionally important for running. Incorporating regional information, we estimated the mean sarcomere strain trajectory and electromyographic (EMG) amplitude of the ILPO during level and incline walking and running. Using these data and data in the literature of muscle energy use, we examined three hypotheses: (1) active lengthening will occur on the ascending limb of the length-tension curve to avoid potential damage caused by stretch on the descending limb; (2) the active strain cycle will shift to favor active shortening when the birds run uphill and shortening will occur on the plateau and shallow ascending limb of the length-tension curve; and (3) measures of EMG intensity will correlate with energy use when the mechanical function of the muscle is similar. Supporting the first hypothesis, we found that the mean sarcomere lengths at the end of active lengthening during level locomotion were smaller than the predicted length at the start of the plateau of the length-tension curve. Supporting the second hypothesis, the magnitude of active lengthening decreased with increasing slope, whereas active shortening increased. In evaluating the relationship between EMG amplitude and energy use (hypothesis 3), we found that although increases in EMG intensity with speed, slope and loading were positively correlated with muscle energy use, the quantitative relationships between these variables differed greatly under different conditions. The relative changes in EMG intensity and energy use by the muscle probably varied because of changes in the mechanical function of the muscle that altered the ratio of muscle energy use to active muscle volume. Considering the overall function of the cycle of active lengthening and shortening of the fascicles of the ILPO, we conclude that the function of active lengthening is unlikely to be energy conservation and may instead be related to promoting stability at the knee. The work required to lengthen the ILPO during stance is provided by co-contracting knee flexors. We suggest that this potentially energetically expensive co-contraction serves to stabilize the knee in early stance by increasing the mechanical impedance of the joint.

  11. Adaptations in muscular activation of the knee extensor muscles with strength training in young and older adults.

    Science.gov (United States)

    Knight, C A; Kamen, G

    2001-12-01

    The purpose of this study was to compare the extent of muscular activation during maximal voluntary knee extension contractions in old and young individuals and to examine the effects of resistance training on muscular activation in each group. The interpolated twitch technique was used to estimate muscular activation during two pre-training baseline tests, and after two and six weeks of resistance training. Throughout the study, the older group was 30% less strong than the young group (p=0.02). The training protocol was effective in both groups with overall isometric strength gains of 30 and 36% in the older (p=0.01) and young (pmuscular activation between groups (p=0.3) did not explain the large disparity in strength. Muscular activation increased by 2% in both groups throughout training (pmuscular strength in the older group, muscular activation was greater than 95% of maximum and appears to be equal in both young and older individuals. Both groups demonstrated similar but small increases in muscular activation throughout training.

  12. Influence of acetaminophen and ibuprofen on in vivo patellar tendon adaptations to knee extensor resistance exercise in older adults

    DEFF Research Database (Denmark)

    Carroll, Chad C; Dickinson, Jared M; Lemoine, Jennifer K;

    2011-01-01

    Millions of older individuals consume acetaminophen or ibuprofen daily and these same individuals are encouraged to participate in resistance training. Several in vitro studies suggest that cyclooxygenase-inhibiting drugs can alter tendon metabolism and may influence adaptations to resistance...

  13. A study on muscle activity and ratio of the knee extensor depending on the types of squat exercise

    Science.gov (United States)

    Kang, Jeong-Il; Park, Joon-Su; Choi, Hyun; Jeong, Dae-Keun; Kwon, Hye-Min; Moon, Young-Jun

    2017-01-01

    [Purpose] For preventing the patellofemoral pain syndrome, this study aims to suggest a proper squat method, which presents selective muscle activity of Vastus Medialis Oblique and muscle activity ratios of Vastus Medialis Oblique/Vastus Lateralis by applying squat that is a representative weight bearing exercise method in various ways depending on the surface conditions and knee bending angles. [Subjects and Methods] An isometric squat that was accompanied by hip adduction, depending on the surface condition and the knee joint flexion angle, was performed by 24 healthy students. The muscle activity and the ratio of muscle activity were measured. [Results] In a comparison of muscle activity depending on the knee joint flexion angle on a weight-bearing surface, the vastus medialis oblique showed a significant difference at 15° and 60°. Meanwhile, in a comparison of the muscle activity ratio between the vastus medialis oblique and the vastus lateralis depending on the knee joint flexion angle on a weight-bearing surface, significant differences were observed at 15° and 60°. [Conclusion] An efficient squat exercise posture for preventing the patellofemoral pain syndrome is to increase the knee joint bending angle on a stable surface. But it would be efficient for patients with difficulties in bending the knee joint to keep a knee joint bending angle of 15 degrees or less on an unstable surface. It is considered that in future, diverse studies on selective Vastus Medialis Oblique strengthening exercise methods would be needed after applying them to patients with the patellofemoral pain syndrome. PMID:28210036

  14. Contractile properties of knee-extensors in one single family with nemaline myopathy: central and peripheral aspects of muscle activation.

    NARCIS (Netherlands)

    Gerrits, K.; Pauw-Gommans, I.M.P.; Engelen, B.G.M. van; Haan, A. de

    2007-01-01

    Patients with nemaline myopathy, a muscle disorder primarily affecting the thin filaments, suffer from weakness which is poorly understood. As disturbed excitation-contraction coupling has been suggested as a possible mechanism, the present study was designed to investigate whether the contractile

  15. High intensity exercise or conventional exercise for patients with rheumatoid arthritis?: outcome expectations of patients, rheumatologists, and physiotherapists.

    NARCIS (Netherlands)

    Munneke, M.; Jong, Z. de; Zwinderman, A.H.; Ronday, H.K.; Ende, C.H.M. van den; Vliet Vlieland, T.P.M.; Hazes, J.M.W.

    2004-01-01

    OBJECTIVE: To examine the outcome expectations of RA patients, rheumatologists, and physiotherapists regarding high intensity exercise programmes compared with conventional exercise programmes. METHODS: An exercise outcome expectations questionnaire was administered to 807 RA patients, 153 rheumatol

  16. High intensity exercise or conventional exercise for patients with rheumatoid arthritis?: outcome expectations of patients, rheumatologists, and physiotherapists.

    NARCIS (Netherlands)

    Munneke, M.; Jong, Z. de; Zwinderman, A.H.; Ronday, H.K.; Ende, C.H.M. van den; Vliet Vlieland, T.P.M.; Hazes, J.M.W.

    2004-01-01

    OBJECTIVE: To examine the outcome expectations of RA patients, rheumatologists, and physiotherapists regarding high intensity exercise programmes compared with conventional exercise programmes. METHODS: An exercise outcome expectations questionnaire was administered to 807 RA patients, 153

  17. High Intensity Interval Training in Handcycling : The Effects of a 7 Week Training Intervention in Able-bodied Men

    NARCIS (Netherlands)

    Schoenmakers, Patrick; Reed, Kate; Van Der Woude, Luc; Hettinga, Florentina J.

    2016-01-01

    INTRODUCTION: In lower body endurance training, quantities of both moderate intensity continuous training (MICT) and high intensity interval training (HIIT) can lead to an improved physiological capacity and performance. Limited research is available regarding the endurance and muscular capacity of

  18. Predicting changes in high-intensity intermittent running performance with acute responses to short jump rope workouts in children

    National Research Council Canada - National Science Library

    Buchheit, Martin; Rabbani, Alireza; Beigi, Hamid Taghi

    2014-01-01

    The aims of the present study were to 1) examine whether individual HR and RPE responses to a jump rope workout could be used to predict changes in high-intensity intermittent running performance in young athletes, and 2...

  19. Low volume short duration high-intensity interval training and repeated sprint ability in Gaelic football players

    OpenAIRE

    Kelly, David

    2014-01-01

    Gaelic Football is the most popular sport in Ireland and is characterized by irregular changes of pace and high-intensity efforts interspersed with periods of light to moderate intensity activity. Speed, power and aerobic capacity are essential fitness components for optimal performance during match play. A high level of aerobic conditioning is required to generate and maintain power output during repeated high intensity activities. Study 1: Anthropometric, physiological, metabolic and en...

  20. High-protein diet induces oxidative stress in rat brain: protective action of high-intensity exercise against lipid peroxidation

    OpenAIRE

    Camiletti-Moir??n, Daniel; Aparicio Garc??a-Molina, Virginia A.; Nebot Valenzuela, Elena; Medina, Gerardo; Mart??nez, Rosario; Kapravelou, Garyfallia; Andrade, Ana; Porres-Foulquie, Jes??s; L??pez-Jurado, Mar??a; Aranda Ram??rez, Pilar

    2015-01-01

    diets as well as aerobic exercise could promote antioxidant capacity and consequently reduce free radicals overproduction on brain. However, little is know regarding to the high-protein diets and high intensity exercise on oxidative stress production. The aim of this study was to analyse the effects of high-protein diets and high-intensity exercise (HIE) on brain oxidative stress markers. Materials and Methods: A total of 40 male Wistar rats were randomly distributed i...