Effect of additional speed endurance training on performance and muscle adaptations

DEFF Research Database (Denmark)

Gunnarsson, Thomas; Christensen, Peter Møller; Holse, Kris

2012-01-01

PURPOSE: The present study examined the effect of additional speed-endurance training during the season on muscle adaptations and performance of trained soccer players. METHODS: Eighteen sub-elite soccer players performed one session with 6-9 30-s intervals at an intensity of 90-95 % ofmaximal...... intensity (speed endurance training; SET) a week for 5 weeks (SET-intervention). Before and after the SET-intervention the players carried out the Yo-Yo intermittent recovery level 2 (Yo- Yo IR2) test, a sprint test (10- and 30-m) and an agility test. In addition, seven of the players had a resting muscle...

Genome-wide association study identifies three novel genetic markers associated with elite endurance performance

DEFF Research Database (Denmark)

Ahmetov, Ii; Kulemin, Na; Popov, Dv

2015-01-01

To investigate the association between multiple single-nucleotide polymorphisms (SNPs), aerobic performance and elite endurance athlete status in Russians. By using GWAS approach, we examined the association between 1,140,419 SNPs and relative maximal oxygen consumption rate ([Formula: see text]O2......max) in 80 international-level Russian endurance athletes (46 males and 34 females). To validate obtained results, we further performed case-control studies by comparing the frequencies of the most significant SNPs (with P endurance athletes and opposite cohorts (192...... Russian controls, 1367 European controls, and 230 Russian power athletes). Initially, six 'endurance alleles' were identified showing discrete associations with [Formula: see text]O2max both in males and females. Next, case-control studies resulted in remaining three SNPs (NFIA-AS2 rs1572312, TSHR rs...

Endurance performance and nocturnal HRV indices.

Science.gov (United States)

Nummela, A; Hynynen, E; Kaikkonen, P; Rusko, H

2010-03-01

The effects of endurance training on endurance performance characteristics and cardiac autonomic modulation during night sleep were investigated. Twenty-four sedentary subjects trained over four weeks two hours per week at an average running intensity of 76+/-4% of their heart rate reserve. The R to R ECG-intervals were recorded and heart rate variability indices including high frequency power (HFP) were calculated for the nights following the training days every week. The subjects were divided into responders and non-responders according to the improvements in the maximal velocity of the incremental treadmill test (v(max)). The responders improved their v(max) by 10.9+/-46 % (p < 0.001) while no changes were observed in the non-responders (1.6+/-3.0%), although there were no differences in any training load variables between the groups. In the responders nocturnal HFP was significantly higher during the fourth training week compared to the first training week (p=0.036). Furthermore, a significant correlation was observed between the change in v(max) and the change in nocturnal HFP (r=0.482, p=0.042). It was concluded that after similar training, an increase in cardiac vagal modulation was related to improved v(max) in the sedentary subjects. Georg Thieme Verlag KG Stuttgart.New York.

Effects of strength training on endurance capacity in top-level endurance athletes

DEFF Research Database (Denmark)

Aagaard, Per; Andersen, Jesper L

2010-01-01

The effect of concurrent strength (S) and endurance (E) training on adaptive changes in aerobic capacity, endurance performance, maximal muscle strength and muscle morphology is equivocal. Some data suggest an attenuated cardiovascular and musculoskeletal response to combined E and S training......, while other data show unimpaired or even superior adaptation compared with either training regime alone. However, the effect of concurrent S and E training only rarely has been examined in top-level endurance athletes. This review describes the effect of concurrent SE training on short-term and long......-term endurance performance in endurance-trained subjects, ranging from moderately trained individuals to elite top-level athletes. It is concluded that strength training can lead to enhanced long-term (>30 min) and short-term (...

Nutritional habits among high-performance endurance athletes

Directory of Open Access Journals (Sweden)

Marius Baranauskas

2015-01-01

Conclusions: The diet of highly trained endurance athletes does not fully meet their requirements and in this situation cannot ensure maximum adaptation to very intense and/or long-duration physical loads. The diet of highly trained endurance athletes must be optimized, adjusted and individualized. Particular attention should be focused on female athletes.

Measuring Ucrit and endurance: equipment choice influences estimates of fish swimming performance.

Science.gov (United States)

Kern, P; Cramp, R L; Gordos, M A; Watson, J R; Franklin, C E

2018-01-01

This study compared the critical swimming speed (U crit ) and endurance performance of three Australian freshwater fish species in different swim-test apparatus. Estimates of U crit measured in a large recirculating flume were greater for all species compared with estimates from a smaller model of the same recirculating flume. Large differences were also observed for estimates of endurance swimming performance between these recirculating flumes and a free-surface swim tunnel. Differences in estimates of performance may be attributable to variation in flow conditions within different types of swim chambers. Variation in estimates of swimming performance between different types of flumes complicates the application of laboratory-based measures to the design of fish passage infrastructure. © 2017 The Fisheries Society of the British Isles.

Self-Control Strength Depletion Reduces Self-Efficacy and Impairs Exercise Performance.

Science.gov (United States)

Graham, Jeffrey D; Bray, Steven R

2015-10-01

The purpose of this study was to investigate the role of task self-efficacy as a psychological factor involved in the relationship between self-control depletion and physical endurance. Participants (N = 37) completed two isometric handgrip endurance trials, separated by a Stroop task, which was either congruent (control) or incongruent (causing depletion). Task self-efficacy for the second endurance trial was measured following the Stroop task. Participants in the depletion condition reported lower task self-efficacy and showed a greater reduction in performance on the second endurance trial when compared with controls. Task self-efficacy also mediated the relationship between self-control depletion and endurance performance. The results of this study provide evidence that task self-efficacy is negatively affected following self-control depletion. We recommend that task self-efficacy be further investigated as a psychological factor accounting for the negative change in self-control performance of physical endurance and sport tasks following self-control strength depletion.

A Clinician Guide to Altitude Training for Optimal Endurance Exercise Performance at Sea Level.

Science.gov (United States)

Constantini, Keren; Wilhite, Daniel P; Chapman, Robert F

2017-06-01

Constantini, Keren, Daniel P. Wilhite, and Robert F. Chapman. A clinician guide to altitude training for optimal endurance exercise performance at sea level. High Alt Med Biol. 18:93-101, 2017.-For well over 50 years, endurance athletes have been utilizing altitude training in an effort to enhance performance in sea level competition. This brief review will offer the clinician a series of evidence-based best-practice guidelines on prealtitude and altitude training considerations, which can ultimately maximize performance improvement outcomes.

Shoulder Girdle Muscles Endurance in Subjects with and without Impingement Syndrome

Directory of Open Access Journals (Sweden)

Afsoun Nodehi-Moghadam

2011-07-01

Full Text Available Objective: Any minimal alteration in performance and coordination of scapular and glenohumeral muscles has the potential to lead to shoulder joint dysfunction. The impingement syndrome has been reported as is the most common diagnosis of shoulder pain. The purpose of this study was to determine whether endurance deficits could be detected in patients with shoulder impingement. Materials & Methods: By convenient sampling 15 patients with impingement syndrome at average of 45.3 years of age and 15 healthy persons (age 45.8 years through a case–control design participated in the study. Endurance of glenohumeral and scapulothoracic muscles were tested with a hand held dynamometer. Independent t–test was used to statistically analyze different groups. Results: Compared to non–impaired subjects, those with impingement syndrome demonstrated a significantly lower endurance of external rotation, scaption and scapular abduction and upward rotation movements (P<0.05. In impingement syndrome patients, the external–to–internal rotator muscles endurance ratio was significantly lower than the control group (P<0.05. Conclusion: The result of the study suggests that endurance deficit of rotator cuff and scapular upward rotator muscles may be an important aspect of the impingement syndrome. Shoulder girdle muscles endurance should be considered in evaluation and physical therapy of impingement syndrome patients.

Impairments of postural stability, core endurance, fall index and functional mobility skills in patients with patello femoral pain syndrome.

Science.gov (United States)

Yilmaz Yelvar, Gul Deniz; Çirak, Yasemin; Dalkilinç, Murat; Demir, Yasemin Parlak; Baltaci, Gul; Kömürcü, Mahmut; Yelvar, Gul Deniz Yilmaz

2016-06-30

Postural control allows performance of daily and sports activities. The previous studies show that postural sway inceases in orthopaedic injuries such as osteoarthritis and total knee arthroplasty. To compare postural sway, risk of falling and function between individuals with and without patellofemoral pain syndrome (PFS). This study included 22 subjects with patellofemoral pain syndrome, age-matched pain-free 22 females serving as a control group. Visual anolog scale and Kujala were used to evaluate the pain. Posturographic assesment was performed by Tetrax posturographic device. Biering Modified Sorenson test for extensor endurance and sit-up test for flexor endurance were used for the evaluation of trunk endurance. Timed get-up and go test was used for lower extremity function. The Student's t Test was used to compare variables between the groups. The Pearson correlation coefficients were calculated to examine correlation between the quantitative variables. Postural sway included eyes open without pillow, eyes open on pillow, eyes closed on pillow, risk of falling, function and postural stabilization included flexor endurance, extansor endurance are impared in patient with patellofemoral pain syndrome when compare to controls. In subjects with PFPS increased postural sway significantly associated with body mass index (r= 0.52), pain duration (r= 0.43), postural control (extansor endurance) (r= -0.50) and risk of falling (r= 0.62) on pillow with open eyes. In addition we found function significantly related with postural control (extansor endurance and flexor endurance) (r= -0.59 and r= -0.59) and risk of falling (r= 0.77)CONCLUSIONS: Decreased neuromuscular control of the trunk core and increased postural sway and falling risk were found in patients with PFPS. Patients may be evaluated for deficits in postural control and falling risk before treatment.

Testing of badminton specific endurance

DEFF Research Database (Denmark)

Madsen, Christian Møller; Højlyng, Mads; Nybo, Lars

2016-01-01

In the present study, a novel intermittent badminton endurance test (B-ENDURANCE) was developed and tested in elite (n=17) and skilled (n=9) badminton players as well as in age-matched physically active men (non-badminton players; n=8). In addition, B-ENDURANCE test-retest reproducibility...... was evaluated in nine badminton players.B-ENDURANCE is an incremental test where each level consists of repeated sequences of badminton specific actions towards the four corners on the court. The subject starts in the center of the court in front of a computer screen and within each sequence he must...... decreases until the subjects cannot follow the dictated tempo.B-ENDURANCE performance for elite players was better (Pbadminton players. In addition, B-ENDURANCE performance correlated (r=0.8; P

Heart rate variability in prediction of individual adaptation to endurance training in recreational endurance runners.

Science.gov (United States)

Vesterinen, V; Häkkinen, K; Hynynen, E; Mikkola, J; Hokka, L; Nummela, A

2013-03-01

The aim of this study was to investigate whether nocturnal heart rate variability (HRV) can be used to predict changes in endurance performance during 28 weeks of endurance training. The training was divided into 14 weeks of basic training (BTP) and 14 weeks of intensive training periods (ITP). Endurance performance characteristics, nocturnal HRV, and serum hormone concentrations were measured before and after both training periods in 28 recreational endurance runners. During the study peak treadmill running speed (Vpeak ) improved by 7.5 ± 4.5%. No changes were observed in HRV indices after BTP, but after ITP, these indices increased significantly (HFP: 1.9%, P=0.026; TP: 1.7%, P=0.007). Significant correlations were observed between the change of Vpeak and HRV indices (TP: r=0.75, PHRV among recreational endurance runners, it seems that moderate- and high-intensity training are needed. This study showed that recreational endurance runners with a high HRV at baseline improved their endurance running performance after ITP more than runners with low baseline HRV. © 2011 John Wiley & Sons A/S.

The Effect of Two Speed Endurance Training Regimes on Performance of Soccer Players.

Directory of Open Access Journals (Sweden)

F Marcello Iaia

Full Text Available In order to better understand the specificity of training adaptations, we compared the effects of two different anaerobic training regimes on various types of soccer-related exercise performances. During the last 3 weeks of the competitive season, thirteen young male professional soccer players (age 18.5±1 yr, height 179.5±6.5 cm, body mass 74.3±6.5 kg reduced the training volume by ~20% and replaced their habitual fitness conditioning work with either speed endurance production (SEP; n = 6 or speed endurance maintenance (SEM; n = 7 training, three times per wk. SEP training consisted of 6-8 reps of 20-s all-out running bouts followed by 2 min of passive recovery, whereas SEM training was characterized by 6-8 x 20-s all-out efforts interspersed with 40 s of passive recovery. SEP training reduced (p<0.01 the total time in a repeated sprint ability test (RSAt by 2.5%. SEM training improved the 200-m sprint performance (from 26.59±0.70 to 26.02±0.62 s, p<0.01 and had a likely beneficial impact on the percentage decrement score of the RSA test (from 4.07±1.28 to 3.55±1.01% but induced a very likely impairment in RSAt (from 83.81±2.37 to 84.65±2.27 s. The distance covered in the Yo-Yo Intermittent Recovery test level 2 was 10.1% (p<0.001 and 3.8% (p<0.05 higher after SEP and SEM training, respectively, with possibly greater improvements following SEP compared to SEM. No differences were observed in the 20- and 40-m sprint performances. In conclusion, these two training strategies target different determinants of soccer-related physical performance. SEP improved repeated sprint and high-intensity intermittent exercise performance, whereas SEM increased muscles' ability to maximize fatigue tolerance and maintain speed development during both repeated all-out and continuous short-duration maximal exercises. These results provide new insight into the precise nature of a stimulus necessary to improve specific types of athletic performance in

Non-conscious visual cues related to affect and action alter perception of effort and endurance performance

Directory of Open Access Journals (Sweden)

Anthony William Blanchfield

2014-12-01

Full Text Available The psychobiological model of endurance performance proposes that endurance performance is determined by a decision-making process based on perception of effort and potential motivation. Recent research has reported that effort-based decision-making during cognitive tasks can be altered by non-conscious visual cues relating to affect and action. The effect of these non-conscious visual cues on effort and performance during physical tasks is however unknown. We report two experiments investigating the effect of subliminal priming with visual cues related to affect and action on perception of effort and endurance performance. In Experiment 1 thirteen individuals were subliminally primed with happy or sad faces as they cycled to exhaustion in a counterbalanced and randomized crossover design. A paired t-test (happy vs. sad faces revealed that individuals cycled for significantly longer (178 s, p = .04 when subliminally primed with happy faces. A 2 x 5 (condition x iso-time ANOVA also revealed a significant main effect of condition on rating of perceived exertion (RPE during the time to exhaustion (TTE test with lower RPE when subjects were subliminally primed with happy faces (p = .04. In Experiment 2, a single-subject randomization tests design found that subliminal priming with action words facilitated a significantly longer (399 s, p = .04 TTE in comparison to inaction words (p = .04. Like Experiment 1, this greater TTE was accompanied by a significantly lower RPE (p = .03. These experiments are the first to show that subliminal visual cues relating to affect and action can alter perception of effort and endurance performance. Non-conscious visual cues may therefore influence the effort-based decision-making process that is proposed to determine endurance performance. Accordingly, the findings raise notable implications for individuals who may encounter such visual cues during endurance competitions, training, or health related exercise.

Effects of caloric restriction and overnight fasting on cycling endurance performance.

Science.gov (United States)

Ferguson, Lisa M; Rossi, Kelly A; Ward, Emily; Jadwin, Emily; Miller, Todd A; Miller, Wayne C

2009-03-01

In addition to aerobic endurance and anaerobic capacity, high power-to-weight ratio (PWR) is important for cycling performance. Cyclists often try to lose weight before race season to improve body composition and optimize PWR. Research has demonstrated body fat-reducing benefits of exercise after fasting overnight. We hypothesized that fasted-state exercise in calorie-restricted trained cyclists would not result in performance decrements and that their PWR would improve significantly. We also hypothesized that substrate use during fasted-state submaximal endurance cycling would shift to greater reliance on fat. Ten trained, competitive cyclists completed a protocol consisting of baseline testing, 3 weeks of caloric restriction (CR), and post-CR testing. The testing sessions measured pre- and post-CR values for resting metabolic rate (RMR), body composition, VO2, PWR and power-to-lean weight ratio (PLWR), and power output, as well as 2-hour submaximal cycling performance, rating of perceived exertion (RPE), and respiratory exchange ratio (RER). There were no significant differences between baseline and post-CR for submaximal trial RER, power output, VO2, RMR, VO2max, or workload at VO2max. However, RPE was significantly lower, and PWR was significantly higher post-CR, whereas RER did not change. The cyclists' PWR and body composition improved significantly, and their overall weight, fat weight, and body fat percentage decreased. Lean mass was maintained. The cyclists' RPE decreased significantly during 2 hours of submaximal cycling post-CR, and there was no decrement in submaximal or maximal cycling performance after 3 weeks of CR combined with overnight fasting. Caloric restriction (up to 40% for 3 weeks) and exercising after fasting overnight can improve a cyclist's PWR without compromising endurance cycling performance.

Cervical Musculoskeletal Impairments and Temporomandibular Disorders

Science.gov (United States)

Magee, David

2012-01-01

ABSTRACT Objectives The study of cervical muscles and their significance in the development and perpetuation of Temporomandibular Disorders has not been elucidated. Thus this project was designed to investigate the association between cervical musculoskeletal impairments and Temporomandibular Disorders. Material and Methods A sample of 154 subjects participated in this study. All subjects underwent a series of physical tests and electromyographic assessment (i.e. head and neck posture, maximal cervical muscle strength, cervical flexor and extensor muscles endurance, and cervical flexor muscle performance) to determine cervical musculoskeletal impairments. Results A strong relationship between neck disability and jaw disability was found (r = 0.82). Craniocervical posture was statistically different between patients with myogenous Temporomandibular Disorders (TMD) and healthy subjects. However, the difference was too small (3.3º) to be considered clinically relevant. Maximal cervical flexor muscle strength was not statistically or clinically different between patients with TMD and healthy subjects. No statistically significant differences were found in electromyographic activity of the sternocleidomastoid or the anterior scalene muscles in patients with TMD when compared to healthy subjects while executing the craniocervical flexion test (P = 0.07). However, clinically important effect sizes (0.42 - 0.82) were found. Subjects with TMD presented with reduced cervical flexor as well as extensor muscle endurance while performing the flexor and extensor muscle endurance tests when compared to healthy individuals. Conclusions Subjects with Temporomandibular Disorders presented with impairments of the cervical flexors and extensors muscles. These results could help guide clinicians in the assessment and prescription of more effective interventions for individuals with Temporomandibular Disorders. PMID:24422022

Cervical Musculoskeletal Impairments and Temporomandibular Disorders

Directory of Open Access Journals (Sweden)

Susan Armijo-Olivo

2012-09-01

Full Text Available Objectives: The study of cervical muscles and their significance in the development and perpetuation of Temporomandibular Disorders has not been elucidated. Thus this project was designed to investigate the association between cervical musculoskeletal impairments and Temporomandibular Disorders. Material and Methods: A sample of 154 subjects participated in this study. All subjects underwent a series of physical tests and electromyographic assessment (i.e. head and neck posture, maximal cervical muscle strength, cervical flexor and extensor muscles endurance, and cervical flexor muscle performance to determine cervical musculoskeletal impairments. Results: A strong relationship between neck disability and jaw disability was found (r = 0.82. Craniocervical posture was statistically different between patients with myogenous Temporomandibular Disorders (TMD and healthy subjects. However, the difference was too small (3.3º to be considered clinically relevant. Maximal cervical flexor muscle strength was not statistically or clinically different between patients with TMD and healthy subjects. No statistically significant differences were found in electromyographic activity of the sternocleidomastoid or the anterior scalene muscles in patients with TMD when compared to healthy subjects while executing the craniocervical flexion test (P = 0.07. However, clinically important effect sizes (0.42 - 0.82 were found. Subjects with TMD presented with reduced cervical flexor as well as extensor muscle endurance while performing the flexor and extensor muscle endurance tests when compared to healthy individuals. Conclusions: Subjects with Temporomandibular Disorders presented with impairments of the cervical flexors and extensors muscles. These results could help guide clinicians in the assessment and prescription of more effective interventions for individuals with Temporomandibular Disorders.

Training modalities: impact on endurance capacity.

Science.gov (United States)

Flueck, Martin; Eilers, Wouter

2010-03-01

Endurance athletes demonstrate an exceptional resistance to fatigue when exercising at high intensity. Much research has been devoted to the contribution of aerobic capacity for the economy of endurance performance. Important aspects of the fine-tuning of metabolic processes and power output in the endurance athlete have been overlooked. This review addresses how training paradigms exploit bioenergetic pathways in recruited muscle groups to promote the endurance phenotype. A special focus is laid on the genome-mediated mechanisms that underlie the conditioning of fatigue resistance and aerobic performance by training macrocycles and complements. The available data on work-induced muscle plasticity implies that different biologic strategies are exploited in athletic and untrained populations to boost endurance capacity. Olympic champions are probably endowed with a unique constitution that renders the conditioning of endurance capacity for competition particularly efficient. Copyright 2010 Elsevier Inc. All rights reserved.

Critical determinants of combined sprint and endurance performance: an integrative analysis from muscle fiber to the human body.

Science.gov (United States)

van der Zwaard, Stephan; van der Laarse, Willem J; Weide, Guido; Bloemers, Frank W; Hofmijster, Mathijs J; Levels, Koen; Noordhof, Dionne A; de Koning, Jos J; de Ruiter, Cornelis J; Jaspers, Richard T

2018-04-01

Optimizing physical performance is a major goal in current physiology. However, basic understanding of combining high sprint and endurance performance is currently lacking. This study identifies critical determinants of combined sprint and endurance performance using multiple regression analyses of physiologic determinants at different biologic levels. Cyclists, including 6 international sprint, 8 team pursuit, and 14 road cyclists, completed a Wingate test and 15-km time trial to obtain sprint and endurance performance results, respectively. Performance was normalized to lean body mass 2/3 to eliminate the influence of body size. Performance determinants were obtained from whole-body oxygen consumption, blood sampling, knee-extensor maximal force, muscle oxygenation, whole-muscle morphology, and muscle fiber histochemistry of musculus vastus lateralis. Normalized sprint performance was explained by percentage of fast-type fibers and muscle volume ( R 2 = 0.65; P body.

Effect of Glycemic Index of a Pre-exercise Meal on Endurance Exercise Performance

NARCIS (Netherlands)

Burdon, Catriona A.; Spronk, Inge; Cheng, Hoi Lun; O’Connor, Helen T.

2017-01-01

Background: Low glycemic index (GI) pre-exercise meals may enhance endurance performance by maintaining euglycemia and altering fuel utilization. However, evidence for performance benefits is equivocal. Objective: To evaluate the effect of a low GI (LGI) versus a high GI (HGI) pre-exercise meal on

Consumo de aminoácidos de cadeia ramificada não afeta o desempenho de endurance Branched-chain amino acids ingestion does not affect endurance performance

Directory of Open Access Journals (Sweden)

Marco Carlos Uchida

2008-02-01

Full Text Available A suplementação com aminoácidos de cadeia ramificada (BCAA é uma das manipulações dietéticas mais populares entre atletas engajados em atividades de endurance. Entretanto, o papel ergogênico destes aminoácidos ainda não está totalmente estabelecido. Portanto, o objetivo do presente trabalho foi avaliar o efeito do consumo de BCAA sobre o exercício de endurance realizado até a exaustão. A fim de provocar redução do estoque de glicogênio muscular e, por conseguinte, maximizar a utilização dos BCAA, os sujeitos (n=17 foram submetidos a uma sessão prévia de exercício (corrida realizada a 75% do VO2max por 40 min seguida por 2 tiros a 90% do VO2max por 10 min cada um. Subseqüentemente, após o consumo aleatório de BCAA (77 mg.kg-1 ou placebo, seguindo modelo duplo cego cruzado, os participantes executaram um teste para determinação da capacidade de endurance (corrida a 90% do Limiar anaeróbio até a exaustão. Ambos os experimentos, BCAA e placebo, foram separados por uma semana. Com relação ao tempo até a exaustão e a distância percorrida, nenhuma diferença foi detectada entre as condições experimentais. (Placebo: 50,1±8,9 vs BCAA: 52,4±4,5 min, respectivamente (Placebo: 8,8±1,3 vs BCAA: 9,1±0,6 km, respectivamente. Além disto, também não foi evidenciada diferença na concentração plasmática de glicose, de lactato e de amônia entre ambas condições experimentais. Em conclusão, a suplementação de BCAA não afetou o desempenho de endurance em um teste de corrida até a exaustão.Branched-chain amino acids (BCAA supplementation is one of the most popular dietary manipulations used by endurance athletes. However, the ergogenic role of these amino acids in endurance exercise is not well established yet. Therefore, the aim of this study was to evaluate the effect of BCAA supplementation upon endurance exercise performed until exhaustion. In order to induce glycogen supply reduction, and thus maximize BCAA

Effects of respiratory muscle endurance training on wheelchair racing performance in athletes with paraplegia: a pilot study.

NARCIS (Netherlands)

Muller, G.; Perret, C.; Hopman, M.T.E.

2008-01-01

OBJECTIVE: Respiratory muscle endurance training (RMET) has been shown to improve both respiratory muscle and cycling exercise endurance in able-bodied subjects. Since effects of RMET on upper extremity exercise performance have not yet been investigated, we evaluated the effects of RMET on 10-km

Cooling During Exercise: An Overlooked Strategy for Enhancing Endurance Performance in the Heat.

Science.gov (United States)

Stevens, Christopher J; Taylor, Lee; Dascombe, Ben J

2017-05-01

It is well established that endurance performance is negatively affected by environmental heat stress due to a complex interaction of physical, physiological and psychological alterations. Numerous scientific investigations have attempted to improve performance in the heat with pre-cooling (cooling prior to an exercise test), and as such this has become a well-established ergogenic practice for endurance athletes. However, the use of mid-cooling (cooling during an exercise test) has received considerably less research attention in comparison, despite recent evidence to suggest that the advantage gained from mid-cooling may outweigh that of pre-cooling. A range of mid-cooling strategies are beneficial for endurance performance in the heat, including the ingestion of cold fluids and ice slurry, both with and without menthol, as well as cooling of the neck and face region via a cooling collar or water poured on the head and face. The combination of pre-cooling and mid-cooling has also been effective, but few comparisons exist between the timing and type of such interventions. Therefore, athletes should experiment with a range of suitable mid-cooling strategies for their event during mock competition scenarios, with the aim to determine their individual tolerable limits and performance benefits. Based on current evidence, the effect of mid-cooling on core temperature appears largely irrelevant to any subsequent performance improvements, while cardiovascular, skin temperature, central nervous system function and psychophysiological factors are likely involved. Research is lacking on elite athletes, and as such it is currently unclear how this population may benefit from mid-cooling.

Nutritional Supplements for Endurance Athletes

Science.gov (United States)

Rasmussen, Christopher J.

Athletes engaged in heavy endurance training often seek additional nutritional strategies to help maximize performance. Specific nutritional supplements exist to combat certain factors that limit performance beginning with a sound everyday diet. Research has further demonstrated that safe, effective, legal supplements are in fact available for today's endurance athletes. Several of these supplements are marketed not only to aid performance but also to combat the immunosuppressive effects of intense endurance training. It is imperative for each athlete to research the legality of certain supplements for their specific sport or event. Once the legality has been established, it is often up to each individual athlete to decipher the ethics involved with ingesting nutritional supplements with the sole intent of improving performance.

Testing of Badminton-Specific Endurance.

Science.gov (United States)

Madsen, Christian M; Højlyng, Mads; Nybo, Lars

2016-09-01

Madsen, CM, Højlyng, M, and Nybo, L. Testing of badminton-specific endurance. J Strength Cond Res 30(9): 2582-2590, 2016-In the present study, a novel intermittent badminton endurance (B-ENDURANCE) test was developed and tested in elite (n = 17) and skilled (n = 9) badminton players and in age-matched physically active men (nonbadminton players; n = 8). In addition, B-ENDURANCE test-retest reproducibility was evaluated in 9 badminton players. The B-ENDURANCE test is an incremental test where each level consists of repeated sequences of badminton-specific actions toward the 4 corners of the court. The subject starts in the center of the court in front of a computer screen and within each sequence, he must, in a randomized order, complete 8 actions as dictated by the computer, providing the audiovisual input and verifying that the appropriate sensor is activated within the allocated time. Recovery time between each sequence is 10 seconds throughout the test, but the time to complete each sequence is gradually decreased until the subjects cannot follow the dictated tempo. The B-ENDURANCE test performance for elite players was better (p ≤ 0.05) compared with the skilled players and nonbadminton players. In addition, the B-ENDURANCE test performance correlated (r = 0.8 and p badminton-specific endurance but at least 1 familiarization trial is recommended if the test is used for evaluation of longitudinal changes, e.g., tracking training effects.

The effect of different dosages of caffeine on endurance performance time

NARCIS (Netherlands)

Pasman, W.J.; Baak, M.A. van; Jeukendrup, A.E.; Haan, A. de

1995-01-01

The effect of different dosages of caffeine (0 - 5 - 9 - 13 mg · kg body weight-1) on endurance performance was examined. Nine well-trained cyclists participated in this study (VO2max 65.1 + 2.6 ml · kg-1 · min-1). Caffeine capsules were administered in random order and double-blind. One hour after

The role of fluid temperature and form on endurance performance in the heat.

Science.gov (United States)

Tan, P M S; Lee, J K W

2015-06-01

Exercising in the heat often results in an excessive increase in body core temperature, which can be detrimental to health and endurance performance. Research in recent years has shifted toward the optimum temperature at which drinks should be ingested. The ingestion of cold drinks can reduce body core temperature before exercise but less so during exercise. Temperature of drinks does not seem to have an effect on the rate of gastric emptying and intestinal absorption. Manipulating the specific heat capacity of a solution can further induce a greater heat sink. Ingestion of ice slurry exploits the additional energy required to convert the solution from ice to water (enthalpy of fusion). Body core temperature is occasionally observed to be higher at the point of exhaustion with the ingestion of ice slurry. There is growing evidence to suggest that ingesting ice slurry is an effective and practical strategy to prevent excessive rise of body core temperature and improve endurance performance. This information is especially important when only a fixed amount of fluid is allowed to be carried, often seen in some ultra-endurance events and military operations. Future studies should evaluate the efficacy of ice slurry in various exercise and environmental conditions. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Low carbohydrate, high fat diet impairs exercise economy and negates the performance benefit from intensified training in elite race walkers

Science.gov (United States)

Ross, Megan L.; Garvican‐Lewis, Laura A.; Welvaert, Marijke; Heikura, Ida A.; Forbes, Sara G.; Mirtschin, Joanne G.; Cato, Louise E.; Strobel, Nicki; Sharma, Avish P.; Hawley, John A.

2017-01-01

Key points Three weeks of intensified training and mild energy deficit in elite race walkers increases peak aerobic capacity independent of dietary support.Adaptation to a ketogenic low carbohydrate, high fat (LCHF) diet markedly increases rates of whole‐body fat oxidation during exercise in race walkers over a range of exercise intensities.The increased rates of fat oxidation result in reduced economy (increased oxygen demand for a given speed) at velocities that translate to real‐life race performance in elite race walkers.In contrast to training with diets providing chronic or periodised high carbohydrate availability, adaptation to an LCHF diet impairs performance in elite endurance athletes despite a significant improvement in peak aerobic capacity. Abstract We investigated the effects of adaptation to a ketogenic low carbohydrate (CHO), high fat diet (LCHF) during 3 weeks of intensified training on metabolism and performance of world‐class endurance athletes. We controlled three isoenergetic diets in elite race walkers: high CHO availability (g kg−1 day−1: 8.6 CHO, 2.1 protein, 1.2 fat) consumed before, during and after training (HCHO, n = 9); identical macronutrient intake, periodised within or between days to alternate between low and high CHO availability (PCHO, n = 10); LCHF (diets providing chronic or periodised high‐CHO availability, and despite a significant improvement in V˙O2 peak , adaptation to the topical LCHF diet negated performance benefits in elite endurance athletes, in part due to reduced exercise economy. PMID:28012184

Relationship between Achilles tendon length and running performance in well-trained male endurance runners.

Science.gov (United States)

Ueno, Hiromasa; Suga, Tadashi; Takao, Kenji; Tanaka, Takahiro; Misaki, Jun; Miyake, Yuto; Nagano, Akinori; Isaka, Tadao

2018-02-01

This study aimed to determine the relationship between Achilles tendon (AT) length and running performance, including running economy, in well-trained endurance runners. We also examined the reasonable portion of the AT related to running performance among AT lengths measured in three different portions. The AT lengths at three portions and cross-sectional area (CSA) of 30 endurance runners were measured using magnetic resonance imaging. Each AT length was calculated as the distance from the calcaneal tuberosity to the muscle-tendon junction of the soleus, gastrocnemius medialis (GM AT ), and gastrocnemius lateralis, respectively. These AT lengths were normalized with shank length. The AT CSA was calculated as the average of 10, 20, and 30 mm above the distal insertion of the AT and normalized with body mass. Running economy was evaluated by measuring energy cost during three 4-minutes submaximal treadmill running trials at 14, 16, and 18 km/h, respectively. Among three AT lengths, only a GM AT correlated significantly with personal best 5000-m race time (r=-.376, P=.046). Furthermore, GM AT correlated significantly with energy cost during submaximal treadmill running trials at 14 km/h and 18 km/h (r=-.446 and -.429, respectively, Prunning performance. These findings suggest that longer AT, especially GM AT , may be advantageous to achieve superior running performance, with better running economy, in endurance runners. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Running performance at high running velocities is impaired but V'O(₂max and peripheral endothelial function are preserved in IL-6⁻/⁻ mice.

Directory of Open Access Journals (Sweden)

Marta Wojewoda

Full Text Available It has been reported that IL-6 knockout mice (IL-6⁻/⁻ possess lower endurance capacity than wild type mice (WT, however the underlying mechanism is poorly understood. The aim of the present work was to examine whether reduced endurance running capacity in IL-6⁻/⁻ mice is linked to impaired maximal oxygen uptake (V'O(₂max, decreased glucose tolerance, endothelial dysfunction or other mechanisms. Maximal running velocity during incremental running to exhaustion was significantly lower in IL-6⁻/⁻ mice than in WT mice (13.00±0.97 m·min⁻¹ vs. 16.89±1.15 m·min⁻¹, P<0.02, respectively. Moreover, the time to exhaustion during running at 12 m·min⁻¹ in IL-6⁻/⁻ mice was significantly shorter (P<0.05 than in WT mice. V'O(₂max in IL-6⁻/⁻ (n = 20 amounting to 108.3±2.8 ml·kg⁻¹·min⁻¹ was similar as in WT mice (n = 22 amounting to 113.0±1.8 ml·kg⁻¹·min⁻¹, (P = 0.16. No difference in maximal COX activity between the IL-6⁻/⁻ and WT mice in m. soleus and m. gastrocnemius was found. Moreover, no impairment of peripheral endothelial function or glucose tolerance was found in IL-6⁻/⁻ mice. Surprisingly, plasma lactate concentration during running at 8 m·min⁻¹ as well at maximal running velocity in IL-6⁻/⁻ mice was significantly lower (P<0.01 than in WT mice. Interestingly, IL-6⁻/⁻ mice displayed important adaptive mechanisms including significantly lower oxygen cost of running at a given speed accompanied by lower expression of sarcoplasmic reticulum Ca²⁺-ATPase and lower plasma lactate concentrations during running at submaximal and maximal running velocities. In conclusion, impaired endurance running capacity in IL-6⁻/⁻ mice could not be explained by reduced V'O(₂max, endothelial dysfunction or impaired muscle oxidative capacity. Therefore, our results indicate that IL-6 cannot be regarded as a major regulator of exercise capacity but rather as a modulator of endurance

Running performance at high running velocities is impaired but V'O(₂max) and peripheral endothelial function are preserved in IL-6⁻/⁻ mice.

Science.gov (United States)

Wojewoda, Marta; Kmiecik, Katarzyna; Ventura-Clapier, Renée; Fortin, Dominique; Onopiuk, Marta; Jakubczyk, Justyna; Sitek, Barbara; Fedorowicz, Andrzej; Majerczak, Joanna; Kaminski, Karol; Chlopicki, Stefan; Zoladz, Jerzy Andrzej

2014-01-01

It has been reported that IL-6 knockout mice (IL-6⁻/⁻) possess lower endurance capacity than wild type mice (WT), however the underlying mechanism is poorly understood. The aim of the present work was to examine whether reduced endurance running capacity in IL-6⁻/⁻ mice is linked to impaired maximal oxygen uptake (V'O(₂max)), decreased glucose tolerance, endothelial dysfunction or other mechanisms. Maximal running velocity during incremental running to exhaustion was significantly lower in IL-6⁻/⁻ mice than in WT mice (13.00±0.97 m·min⁻¹ vs. 16.89±1.15 m·min⁻¹, P<0.02, respectively). Moreover, the time to exhaustion during running at 12 m·min⁻¹ in IL-6⁻/⁻ mice was significantly shorter (P<0.05) than in WT mice. V'O(₂max) in IL-6⁻/⁻ (n = 20) amounting to 108.3±2.8 ml·kg⁻¹·min⁻¹ was similar as in WT mice (n = 22) amounting to 113.0±1.8 ml·kg⁻¹·min⁻¹, (P = 0.16). No difference in maximal COX activity between the IL-6⁻/⁻ and WT mice in m. soleus and m. gastrocnemius was found. Moreover, no impairment of peripheral endothelial function or glucose tolerance was found in IL-6⁻/⁻ mice. Surprisingly, plasma lactate concentration during running at 8 m·min⁻¹ as well at maximal running velocity in IL-6⁻/⁻ mice was significantly lower (P<0.01) than in WT mice. Interestingly, IL-6⁻/⁻ mice displayed important adaptive mechanisms including significantly lower oxygen cost of running at a given speed accompanied by lower expression of sarcoplasmic reticulum Ca²⁺-ATPase and lower plasma lactate concentrations during running at submaximal and maximal running velocities. In conclusion, impaired endurance running capacity in IL-6⁻/⁻ mice could not be explained by reduced V'O(₂max), endothelial dysfunction or impaired muscle oxidative capacity. Therefore, our results indicate that IL-6 cannot be regarded as a major regulator of exercise capacity but rather as a modulator of endurance

Running Performance at High Running Velocities Is Impaired but V′O2max and Peripheral Endothelial Function Are Preserved in IL-6−/− Mice

Science.gov (United States)

Wojewoda, Marta; Kmiecik, Katarzyna; Ventura-Clapier, Renée; Fortin, Dominique; Onopiuk, Marta; Jakubczyk, Justyna; Sitek, Barbara; Fedorowicz, Andrzej; Majerczak, Joanna; Kaminski, Karol; Chlopicki, Stefan; Zoladz, Jerzy Andrzej

2014-01-01

It has been reported that IL-6 knockout mice (IL-6−/−) possess lower endurance capacity than wild type mice (WT), however the underlying mechanism is poorly understood. The aim of the present work was to examine whether reduced endurance running capacity in IL-6−/− mice is linked to impaired maximal oxygen uptake (V′O2max), decreased glucose tolerance, endothelial dysfunction or other mechanisms. Maximal running velocity during incremental running to exhaustion was significantly lower in IL-6−/− mice than in WT mice (13.00±0.97 m.min−1 vs. 16.89±1.15 m.min−1, P<0.02, respectively). Moreover, the time to exhaustion during running at 12 m.min−1 in IL-6−/− mice was significantly shorter (P<0.05) than in WT mice. V′O2max in IL-6−/− (n = 20) amounting to 108.3±2.8 ml.kg−1.min−1 was similar as in WT mice (n = 22) amounting to 113.0±1.8 ml.kg−1.min−1, (P = 0.16). No difference in maximal COX activity between the IL-6−/− and WT mice in m. soleus and m. gastrocnemius was found. Moreover, no impairment of peripheral endothelial function or glucose tolerance was found in IL-6−/− mice. Surprisingly, plasma lactate concentration during running at 8 m.min−1 as well at maximal running velocity in IL-6−/− mice was significantly lower (P<0.01) than in WT mice. Interestingly, IL-6−/− mice displayed important adaptive mechanisms including significantly lower oxygen cost of running at a given speed accompanied by lower expression of sarcoplasmic reticulum Ca2+-ATPase and lower plasma lactate concentrations during running at submaximal and maximal running velocities. In conclusion, impaired endurance running capacity in IL-6−/− mice could not be explained by reduced V′O2max, endothelial dysfunction or impaired muscle oxidative capacity. Therefore, our results indicate that IL-6 cannot be regarded as a major regulator of exercise capacity but rather as a modulator of endurance performance. Furthermore, we

Pedalling rate affects endurance performance during high-intensity cycling

DEFF Research Database (Denmark)

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

2004-01-01

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......, and endurance time at W90 with FCPR-25, FCPR, and FCPR+25. Power reserve was calculated as the difference between applied power output at a given pedalling rate and peak crank power at this same pedalling rate. W90 was 325 (47) W. FCPR at W90 was 78 (11) rpm, resulting in FCPR-25 being 59 (8) rpm and FCPR+25...... 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...

Decline in measured glomerular filtration rate is associated with a decrease in endurance, strength, balance and fine motor skills.

Science.gov (United States)

Hellberg, Matthias; Höglund, Peter; Svensson, Philippa; Abdulahi, Huda; Clyne, Naomi

2017-07-01

Physical performance in chronic kidney disease affects morbidity and mortality. The aim was to find out which measures of physical performance are important in chronic kidney disease (CKD) and if there are associations with declining measured glomerular filtration rate (GFR). Endurance was assessed by 6 min walk test (6-MWT) and stair climbing, muscular endurance by 30 s sit to stand, heel rises and toe lifts, strength by quadriceps- and handgrip-strength, balance by functional reach and Berg's balance scale, and fine motor skills by Moberg's picking-up test. GFR was measured by Iohexol clearance. The study comprised 101 patients with CKD 3b-5 not started dialysis, 40 women and 61 men, with a mean age of 67 ± 13 (range: 22 - 87) years. All measures of physical performance were impaired. A decrease in GFR of 10 mL/min per 1.73 m 2 corresponded to a 35 metre shorter walking distance in the 6-MWT. Multivariable linear regression analysis showed significant relationships between decline in GFR and the 6-MWT (P = 0.04), isometric quadriceps strength left (P = 0.04), balance measured as functional reach (P = 0.02) and fine motor skills in the left hand as measured by Moberg's picking-up test (P = 0.01), respectively, after sex, age, comorbidity and the interaction between sex and age had been taken into account. Endurance, muscular endurance, strength, balance and fine motor skills were impaired in patients with CKD 3b-5. Walking capacity, isometric quadriceps strength, balance, and fine motor skills were associated with declining GFR. The left extremities were more susceptible to GFR, ageing and comorbidities and seem thus to be more sensitive. © 2016 Asian Pacific Society of Nephrology.

Effect of pre-cooling, with and without thigh cooling, on strain and endurance exercise performance in the heat.

Science.gov (United States)

Cotter, J D; Sleivert, G G; Roberts, W S; Febbraio, M A

2001-04-01

Body cooling before exercise (i.e. pre-cooling) reduces physiological strain in humans during endurance exercise in temperate and warm environments, usually improving performance. This study examined the effectiveness of pre-cooling humans by ice-vest and cold (3 degrees C) air, with (LC) and without (LW) leg cooling, in reducing heat strain and improving endurance performance in the heat (35 degrees C, 60% RH). Nine habitually-active males completed three trials, involving pre-cooling (LC and LW) or no pre-cooling (CON: 34 degrees C air) before 35-min cycle exercise: 20 min at approximately 65% VO2peak then a 15-min work-performance trial. At exercise onset, mean core (Tc, from oesophagus and rectum) and skin temperatures, forearm blood flow (FBF), heart rate (HR), and ratings of exertion, body temperature and thermal discomfort were lower in LW and LC than CON (Pcooling by ice-vest and cold air effectively reduced physiological and psychophysical strain and improved endurance performance in the heat, irrespective of whether thighs were warmed or cooled.

Should Body Size Categories Be More Common in Endurance Running Events?

Science.gov (United States)

Buresh, Robert

2018-05-01

Thousands of endurance running events are held each year in the United States, and most of them use age and sex categories to account for documented effects of those factors on running performance. However, most running events do not provide categories of body mass, despite abundant evidence that it, too, dramatically influences endurance running performance. The purposes of this article are to (1) discuss how body mass affects endurance running performance, (2) explain several mechanisms through which body mass influences endurance running performance, and (3) suggest possible ways in which body mass might be categorized in endurance running events.

Determinants of time trial performance and maximal incremental exercise in highly trained endurance athletes

DEFF Research Database (Denmark)

Jacobs, Robert Acton; Rasmussen, Peter; Siebenmann, Christoph

2011-01-01

Human endurance performance can be predicted from maximal oxygen consumption (VO(2max)), lactate threshold, and exercise efficiency. These physiologic parameters, however, are not wholly exclusive from one another and their interplay is complex. Accordingly, we sought to identify more specific me...

The Effect of Two Speed Endurance Training Regimes on Performance of Soccer Players

Science.gov (United States)

Iaia, F. Marcello; Fiorenza, Matteo; Perri, Enrico; Alberti, Giampietro; Millet, Grégoire P.; Bangsbo, Jens

2015-01-01

In order to better understand the specificity of training adaptations, we compared the effects of two different anaerobic training regimes on various types of soccer-related exercise performances. During the last 3 weeks of the competitive season, thirteen young male professional soccer players (age 18.5±1 yr, height 179.5±6.5 cm, body mass 74.3±6.5 kg) reduced the training volume by ~20% and replaced their habitual fitness conditioning work with either speed endurance production (SEP; n = 6) or speed endurance maintenance (SEM; n = 7) training, three times per wk. SEP training consisted of 6–8 reps of 20-s all-out running bouts followed by 2 min of passive recovery, whereas SEM training was characterized by 6–8 x 20-s all-out efforts interspersed with 40 s of passive recovery. SEP training reduced (pstrategies target different determinants of soccer-related physical performance. SEP improved repeated sprint and high-intensity intermittent exercise performance, whereas SEM increased muscles’ ability to maximize fatigue tolerance and maintain speed development during both repeated all-out and continuous short-duration maximal exercises. These results provide new insight into the precise nature of a stimulus necessary to improve specific types of athletic performance in trained young soccer players. PMID:26394225

Effects of Hemopure on maximal oxygen uptake and endurance performance in healthy humans.

Science.gov (United States)

Ashenden, M J; Schumacher, Y O; Sharpe, K; Varlet-Marie, E; Audran, M

2007-05-01

Haemoglobin-based oxygen carriers (HBOCs) such as Hemopure are touted as a tenable substitute for red blood cells and therefore potential doping agents, although the mechanisms of oxygen transport of HBOCs are incompletely understood. We investigated whether infusion of Hemopure increased maximal oxygen uptake (V.O 2max) and endurance performance in healthy subjects. Twelve male subjects performed two 4-minute submaximal exercise bouts equivalent to 60 % and 75 % of V.O (2max) on a cycle ergometer, followed by a ramped incremental protocol to elicit V.O (2max). A crossover design tested the effect of infusing either 30 g (6 subjects) or 45 g (6 subjects) of Hemopure versus a placebo. Under our study conditions, Hemopure did not increase V.O (2max) nor endurance performance. However, the infusion of Hemopure caused a decrease in heart rate of approximately 10 bpm (p=0.009) and an average increase in mean ( approximately 7 mmHg) and diastolic blood pressure ( approximately 8 mmHg) (p=0.046) at submaximal and maximal exercise intensities. Infusion of Hemopure did not bestow the same physiological advantages generally associated with infusion of red blood cells. It is conceivable that under exercise conditions, the hypertensive effects of Hemopure counter the performance-enhancing effect of improved blood oxygen carrying capacity.

Comparison of an Intermittent Hypoxic Exposure Acclimatization Program to Staging at Moderate Altitude on Endurance Performance at 4300 m

Science.gov (United States)

2009-10-01

Endurance Performance at 4300 m 7 - 6 RTO-MP-HFM-181 breakfast volunteers were provided with two commercially available energy bars and fruit juice ...food composition = 510 kcal, 14 gm fat, 65 gm carbohydrate, 32 gm protein) at 1 to 2 hrs prior to the beginning of each of the cycle endurance test...JE, Robinson SR, Skrinar GS, Lewis SF and Sawka MN. Intermittent altitude exposures improve muscular performance at 4,300 m. J Appl Physiol 95

Significant Effect of a Pre-Exercise High-Fat Meal after a 3-Day High-Carbohydrate Diet on Endurance Performance

Directory of Open Access Journals (Sweden)

Ikuma Murakami

2012-06-01

Full Text Available We investigated the effect of macronutrient composition of pre-exercise meals on endurance performance. Subjects consumed a high-carbohydrate diet at each meal for 3 days, followed by a high-fat meal (HFM; 1007 ± 21 kcal, 30% CHO, 55% F and 15% P or high-carbohydrate meal (HCM; 1007 ± 21 kcal, 71% CHO, 20% F and 9% P 4 h before exercise. Furthermore, just prior to the test, subjects in the HFM group ingested either maltodextrin jelly (M or a placebo jelly (P, while subjects in the HCM ingested a placebo jelly. Endurance performance was measured as running time until exhaustion at a speed between lactate threshold and the onset of blood lactate accumulation. All subjects participated in each trial, randomly assigned at weekly intervals. We observed that the time until exhaustion was significantly longer in the HFM + M (p < 0.05 than in HFM + P and HCM + P conditions. Furthermore, the total amount of fat oxidation during exercise was significantly higher in HFM + M and HFM + P than in HCM + P (p < 0.05. These results suggest that ingestion of a HFM prior to exercise is more favorable for endurance performance than HCM. In addition, HFM and maltodextrin ingestion following 3 days of carbohydrate loading enhances endurance running performance.

Central dopaminergic neurotransmission plays an important role in thermoregulation and performance during endurance exercise.

Science.gov (United States)

Zheng, Xinyan; Hasegawa, Hiroshi

2016-10-01

Dopamine (DA) has been widely investigated for its potential role in determining exercise performance. It was originally thought that DA's ergogenic effect was by mediating psychological responses. Recently, some studies have also suggested that DA may regulate physiological responses, such as thermoregulation. Hyperthermia has been demonstrated as an important limiting factor during endurance exercise. DA is prominent in the thermoregulatory centre, and changes in DA concentration have been shown to affect core temperature regulation during exercise. Some studies have proposed that DA or DA/noradrenaline (NA) reuptake inhibitors can improve exercise performance, despite hyperthermia during exercise in the heat. DA/NA reuptake inhibitors also increase catecholamine release in the thermoregulatory centre. Intracerebroventricularly injected DA has been shown to improve exercise performance through inhibiting hyperthermia-induced fatigue, even at normal ambient temperatures. Further, caffeine has been reported to increase DA release in the thermoregulatory centre and improves endurance exercise performance despite increased core body temperature. Taken together, DA has been shown to have ergogenic effects and increase heat storage and hyperthermia tolerance. The mechanisms underlying these effects seem to involve limiting/overriding the inhibitory signals from the central nervous system that result in cessation of exercise due to hyperthermia.

Effects of Endurance and Endurance Strength Training on Body Composition and Physical Capacity in Women with Abdominal Obesity

Science.gov (United States)

Skrypnik, Damian; Bogdański, Paweł; Mądry, Edyta; Karolkiewicz, Joanna; Ratajczak, Marzena; Kryściak, Jakub; Pupek-Musialik, Danuta; Walkowiak, Jarosław

2015-01-01

Aims To compare the effects of endurance training with endurance strength training on the anthropometric, body composition, physical capacity, and circulatory parameters in obese women. Methods 44 women with abdominal obesity were randomized into groups A and B, and asked to perform endurance (A) and endurance strength training (B) for 3 months, 3 times/week, for 60 min. Dual-energy X-ray absorptiometry and Graded Exercise Test were performed before and after training. Results Significant decreases in body mass, BMI, total body fat, total body fat mass, and waist and hip circumference were observed after both types of intervention. Marked increases in total body lean and total body fat-free mass were documented in group B. In both groups, significant increases in peak oxygen uptake, time to exhaustion, maximal work rate, and work rate at ventilatory threshold were accompanied by noticeably decreased resting heart rate, resting systolic blood pressure, and resting and exercise diastolic blood pressure. No significant differences were noticed between groups for the investigated parameters. Conclusion Our findings demonstrate evidence for a favorable and comparable effect of 3-month endurance and endurance strength training on anthropometric parameters, body composition, physical capacity, and circulatory system function in women with abdominal obesity. PMID:25968470

The effect of almond consumption on elements of endurance exercise performance in trained athletes

Science.gov (United States)

Almonds are a healthy tree nut food with high nutrient density. Their consumption has been shown to ameliorate oxidative stress, inflammation, etc. The objective of the study was to examine the effect of almonds on elements of endurance exercise performance in trained athletes. A 10-week crossover, ...

Increased trunk extension endurance is associated with meaningful improvement in balance among older adults with mobility problems.

Science.gov (United States)

Suri, Pradeep; Kiely, Dan K; Leveille, Suzanne G; Frontera, Walter R; Bean, Jonathan F

2011-07-01

To determine whether trunk extension endurance changes with training are associated with clinically meaningful improvements in balance among mobility-limited older adults. Longitudinal data from a randomized controlled trial. Outpatient rehabilitation research center. Community-dwelling older adults (N=64; mean age, 75.9y) with mobility limitations as defined by a score of 4 to 10 on the Short Physical Performance Battery. Sixteen weeks of progressive resistance training. Outcomes were the Berg Balance Scale (BBS) and the Unipedal Stance Time (UST). Predictors included leg strength, leg power, trunk extension endurance, and the product of heart rate and blood pressure (RPP) at the final stage of an exercise tolerance test. We performed an analysis of data from participants who completed 16 weeks of training by using binary outcomes defined by a clinically meaningful change (CMC) from baseline to completion of the intervention (BBS=4 units; UST=5s). The association of predictor variables with balance outcomes was examined separately and together in multivariate adjusted logistic regression models. Trunk extension endurance in seconds (1.04 [1.00-1.09]) was independently associated with CMC on the BBS. Trunk extension endurance (1.02 [1.00-1.03]) was independently associated with CMC on the UST. Other physical attributes were not associated with meaningful change in balance. Improvements in trunk extension endurance were independently associated with CMCs in balance in older adults. Leg strength, leg power, and RPP were not associated with CMC in balance. Poor trunk extension endurance may be a rehabilitative impairment worthy of further study as a modifiable factor linked to balance among older adults. Copyright © 2011 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Resting sympatho-vagal balance is related to 10 km running performance in master endurance athletes

Directory of Open Access Journals (Sweden)

Angelo Cataldo

2018-02-01

Full Text Available Relationships between heart rate recovery after exercise (HRR, baseline heart rate variability measures (HRV, and time to perform a 10Km running trial (t10Km were evaluated in "master" athletes of endurance to assess whether the measured indexes may be useful for monitoring the training status of the athletes. Ten “master” athletes of endurance, aged 40-60 years, were recruited. After baseline measures of HRV, the athletes performed a graded maximal test on treadmill and HRR was measured at 1 and 2 minutes from recovery. Subsequently they performed a 10Km running trial and t10Km was related to HRV and HRR indexes. The time to perform a 10Km running trial was significantly correlated with baseline HRV indexes. No correlation was found between t10Km and HRR. Baseline HRV measures, but not HRR, were significantly correlated with the time of performance on 10km running in “master” athletes. The enhanced parasympathetic function at rest appears to be a condition to a better performance on 10km running. HRV can be simple and useful measurements for monitoring the training stratus of athletes and their physical condition in proximity of a competition.

Master athletes are extending the limits of human endurance

Directory of Open Access Journals (Sweden)

Romuald Lepers

2016-12-01

Full Text Available The increased participation of master athletes (i.e. > 40 years old in endurance and ultra-endurance events (> 6h duration over the past few decades has been accompanied by an improvement in their performances at a much faster rate than their younger counterparts. Ageing does however result in a decrease in overall endurance performance. Such age-related declines in performance depend upon the modes of locomotion, event duration and gender of the participant. For example, smaller age-related declines in cycling performance than in running and swimming have been documented. The relative stability of gender differences observed across the ages suggests that the age-related declines in physiological function did not differ between males and females. Among the main physiological determinants of endurance performance, the maximal oxygen consumption (VO2max appears to be the parameter that is most altered by age. Exercise economy and the exercise intensity at which a high fraction of VO2max can be sustained (i.e. lactate threshold, seem to decline to a lesser extent with advancing age. The ability to maintain a high exercise-training stimulus with advancing age is emerging as the single most important means of limiting the rate of decline in endurance performance. By constantly extending the limits of (ultra-endurance, master athletes therefore represent an important insight into the ability of humans to maintain physical performance and physiological function with advancing age.

The Supplementation of Branched-Chain Amino Acids, Arginine, and Citrulline Improves Endurance Exercise Performance in Two Consecutive Days

Directory of Open Access Journals (Sweden)

I-Shiung Cheng, Yi-Wen Wang, I-Fan Chen, Gi-Sheng Hsu, Chun-Fang Hsueh, Chen-Kang Chang

2016-09-01

Full Text Available The central nervous system plays a crucial role in fatigue during endurance exercise. Branched-chain amino acids (BCAA could reduce cerebral serotonin synthesis by competing with its precursor tryptophan for crossing the blood brain barrier. Arginine and citrulline could prevent excess hyperammonemia accompanied by BCAA supplementation. This study investigated the combination of BCAA, arginine, and citrulline on endurance performance in two consecutive days. Seven male and three female endurance runners ingested 0.17 g·kg-1 BCAA, 0.05 g·kg-1 arginine and 0.05 g·kg-1 citrulline (AA trial or placebo (PL trial in a randomized cross-over design. Each trial contained a 5000 m time trial on the first day, and a 10000 m time trial on the second day. The AA trial had significantly better performance in 5000 m (AA: 1065.7 ± 33.9 s; PL: 1100.5 ± 40.4 s and 10000 m (AA: 2292.0 ± 211.3 s; PL: 2375.6 ± 244.2 s. The two trials reported similar ratings of perceived exertion. After exercise, the AA trial had significantly lower tryptophan/BCAA ratio, similar NH3, and significantly higher urea concentrations. In conclusion, the supplementation could enhance time-trial performance in two consecutive days in endurance runners, possibly through the inhibition of cerebral serotonin synthesis by BCAA and the prevention of excess hyperammonemia by increased urea genesis.

The human endurance athlete: heterogeneity and adaptability of ...

African Journals Online (AJOL)

In human subjects, large variations between individuals (up to 3-fold) exist in the capacity for endurance exercise performance. In a heterogeneous population, endurance performance is strongly related to whole body maximal oxygen uptake (VO2 max). This is in part genotype dependent (~25%) but is adaptable with ...

Keto-adaptation enhances exercise performance and body composition responses to training in endurance athletes.

Science.gov (United States)

McSwiney, Fionn T; Wardrop, Bruce; Hyde, Parker N; Lafountain, Richard A; Volek, Jeff S; Doyle, Lorna

2018-04-01

Low-carbohydrate diets have recently grown in popularity among endurance athletes, yet little is known about the long-term (>4wk) performance implications of consuming a low-carbohydrate high fat ketogenic diet (LCKD) in well-trained athletes. Twenty male endurance-trained athletes (age 33±11y, body mass 80±11kg; BMI 24.7±3.1kg/m 2 ) who habitually consumed a carbohydrate-based diet, self-selected into a high-carbohydrate (HC) group (n=11, %carbohydrate:protein:fat=65:14:20), or a LCKD group (n=9, 6:17:77). Both groups performed the same training intervention (endurance, strength and high intensity interval training (HIIT)). Prior to and following successful completion of 12-weeks of diet and training, participants had their body composition assessed, and completed a 100km time trial (TT), six second (SS) sprint, and a critical power test (CPT). During post-intervention testing the HC group consumed 30-60g/h carbohydrate, whereas the LCKD group consumed water, and electrolytes. The LCKD group experienced a significantly greater decrease in body mass (HC -0.8kg, LCKD -5.9kg; P=0.006, effect size (ES): 0.338) and percentage body fat percentage (HC -0.7%, LCKD -5.2%; P=0.008, ES: 0.346). Fasting serum beta-hydroxybutyrate (βHB) significantly increased from 0.1 at baseline to 0.5mmol/L in the LCKD group (P=0.011, ES: 0.403) in week 12. There was no significant change in performance of the 100km TT between groups (HC -1.13min·s, LCKD -4.07min·s, P=0.057, ES: 0.196). SS sprint peak power increased by 0.8 watts per kilogram bodyweight (w/kg) in the LCKD group, versus a -0.1w/kg reduction in the HC group (P=0.025, ES: 0.263). CPT peak power decreased by -0.7w/kg in the HC group, and increased by 1.4w/kg in the LCKD group (P=0.047, ES: 0.212). Fat oxidation in the LCKD group was significantly greater throughout the 100km TT. Compared to a HC comparison group, a 12-week period of keto-adaptation and exercise training, enhanced body composition, fat oxidation during

Chronic Endurance Exercise Impairs Cardiac Structure and Function in Middle-Aged Mice with Impaired Nrf2 Signaling

Directory of Open Access Journals (Sweden)

Gobinath Shanmugam

2017-05-01

Full Text Available Nuclear factor erythroid 2 related factor 2 (Nrf2 signaling maintains the redox homeostasis and its activation is shown to suppress cardiac maladaptation. Earlier we reported that acute endurance exercise (2 days evoked antioxidant cytoprotection in young WT animals but not in aged WT animals. However, the effect of repeated endurance exercise during biologic aging (WT characterized by an inherent deterioration in Nrf2 signaling and pathological aging (pronounced oxidative susceptibility—Nrf2 absence in the myocardium remains elusive. Thus, the purpose of our study was to determine the effect of chronic endurance exercise-induced cardiac adaptation in aged mice with and without Nrf2. Age-matched WT and Nrf2-null mice (Nrf2−/− (>22 months were subjected to 6 weeks chronic endurance exercise (25 meter/min, 12% grade. The myocardial redox status was assessed by expression of antioxidant defense genes and proteins along with immunochemical detection of DMPO-radical adduct, GSH-NEM, and total ubiquitination. Cardiac functions were assessed by echocardiography and electrocardiogram. At sedentary state, loss of Nrf2 resulted in significant downregulation of antioxidant gene expression (Nqo1, Ho1, Gclm, Cat, and Gst-α with decreased GSH-NEM immuno-fluorescence signals. While Nrf2−/− mice subjected to CEE showed an either similar or more pronounced reduction in the transcript levels of Gclc, Nqo1, Gsr, and Gst-α in relation to WT littermates. In addition, the hearts of Nrf2−/− on CEE showed a substantial reduction in specific antioxidant proteins, G6PD and CAT along with decreased GSH, a pronounced increase in DMPO-adduct and the total ubiquitination levels. Further, CEE resulted in a significant upregulation of hypertrophy genes (Anf, Bnf, and β-Mhc (p < 0.05 in the Nrf2−/− hearts in relation to WT mice. Moreover, the aged Nrf2−/− mice exhibited a higher degree of cardiac remodeling in association with a significant decrease in

Ketogenic diets and physical performance

Directory of Open Access Journals (Sweden)

Phinney SD

2004-08-01

Full Text Available Impaired physical performance is a common but not obligate result of a low carbohydrate diet. Lessons from traditional Inuit culture indicate that time for adaptation, optimized sodium and potassium nutriture, and constraint of protein to 15-25 % of daily energy expenditure allow unimpaired endurance performance despite nutritional ketosis.

Increased Blood Lactate Level Deteriorates Running Economy in World Class Endurance Athletes.

Science.gov (United States)

Hoff, Jan; Støren, Øyvind; Finstad, Arnstein; Wang, Eivind; Helgerud, Jan

2016-05-01

Blood lactate accumulation is associated with development of muscle fatigue and negatively correlated to endurance performance. No research has quantified the effects of lactate presence at moderate levels of lactate accumulation. The purpose of this study was to test whether 2 moderate blood lactate concentration levels affect running economy (RE) when running at the individual lactate threshold (LT). Seven male world class endurance athletes with an average V[Combining Dot Above]O2max of 80.7 ± 2.7 ml·kg·min or 5.8 ± 0.5 L·min participated in this study. After the V[Combining Dot Above]O2max test, the subjects were resting or walking and in a random order tested for RE at their LT velocity when the blood lactate level reached either 3 mmol·L or 5 mmol·L. After a new 5-minute exercising period at maximal aerobic velocity, the crossover lactate value RE testing was performed. Running economy was significantly (p ≤ 0.05) deteriorated from 0.668 ± 0.044 to 0.705 ± 0.056 ml·kg·m or 5.5% (p ≤ 0.05) for blood lactate level of 3 mmol·L compared with 5 mmol·L, respectively. Increased lactate level from 3 to 5 mmol·L is thus accompanied by deteriorated RE at LT running velocity. The deteriorated RE at moderate levels of lactate concentration emphasizes the importance of avoiding intensities above LT in the early parts of a dominantly aerobic endurance competition. It also emphasizes the importance of a high V[Combining Dot Above]O2max for aerobic endurance athletes and may partly explain the V[Combining Dot Above]O2 slow component as impaired RE.

Ketogenic diets and physical performance

Directory of Open Access Journals (Sweden)

Phinney Stephen D

2004-08-01

Full Text Available Abstract Impaired physical performance is a common but not obligate result of a low carbohydrate diet. Lessons from traditional Inuit culture indicate that time for adaptation, optimized sodium and potassium nutriture, and constraint of protein to 15–25 % of daily energy expenditure allow unimpaired endurance performance despite nutritional ketosis.

Tests for predicting endurance kayak performance | Olivier | South ...

African Journals Online (AJOL)

Methods : The following variables were measured on 23 competitive endurance kayakers, who provided written informed consent : Arm crank VO2 peak; 1 minute dips; armspan; modified sit-and-reach; grip strength; body mass; height. These were selected on the basis of their being identified as possibly contributing to ...

Hypoxic training methods for improving endurance exercise performance

Directory of Open Access Journals (Sweden)

Jacob A. Sinex

2015-12-01

Full Text Available Endurance athletic performance is highly related to a number of factors that can be altered through altitude and hypoxic training including increases in erythrocyte volume, maximal aerobic exercise capacity, capillary density, and economy. Physiological adaptations in response to acute and chronic exposure to hypoxic environments are well documented and range from short-term detrimental effects to longer-term adaptations that can improve performance at altitude and in sea-level competitions. Many altitude and hypoxic training protocols have been developed, employing various combinations of living and training at sea-level, low, moderate, and high altitudes and utilizing natural and artificial altitudes, with varying degrees of effectiveness. Several factors have been identified that are associated with individual responses to hypoxic training, and techniques for identifying those athletes most likely to benefit from hypoxic training continue to be investigated. Exposure to sufficiently high altitude (2000–3000 m for more than 12 h/day, while training at lower altitudes, for a minimum of 21 days is recommended. Timing of altitude training related to competition remains under debate, although general recommendations can be considered.

Effect of Vertical, Horizontal, and Combined Plyometric Training on Explosive, Balance, and Endurance Performance of Young Soccer Players.

Science.gov (United States)

Ramírez-Campillo, Rodrigo; Gallardo, Francisco; Henriquez-Olguín, Carlos; Meylan, Cesar M P; Martínez, Cristian; Álvarez, Cristian; Caniuqueo, Alexis; Cadore, Eduardo L; Izquierdo, Mikel

2015-07-01

The aim of this study was to compare the effects of 6 weeks of vertical, horizontal, or combined vertical and horizontal plyometric training on muscle explosive, endurance, and balance performance. Forty young soccer players aged between 10 and 14 years were randomly divided into control (CG; n = 10), vertical plyometric group (VG; n = 10), horizontal plyometric group (HG; n = 10), and combined vertical and horizontal plyometric group (VHG; n = 10). Players performance in the vertical and horizontal countermovement jump with arms, 5 multiple bounds test (MB5), 20-cm drop jump reactive strength index (RSI20), maximal kicking velocity (MKV), sprint, change of direction speed (CODS), Yo-Yo intermittent recovery level 1 test (Yo-Yo IR1), and balance was measured. No significant or meaningful changes in the CG, apart from small change in the Yo-Yo IR1, were observed while all training programs resulted in meaningful changes in explosive, endurance, and balance performance. However, only VHG showed a statistically significant (p ≤ 0.05) increase in all performance test and most meaningful training effect difference with the CG across tests. Although no significant differences in performance changes were observed between experimental groups, the VHG program was more effective compared with VG (i.e., jumps, MKV, sprint, CODS, and balance performance) and HG (i.e., sprint, CODS, and balance performance) to small effect. The study demonstrated that vertical, horizontal, and combined vertical and horizontal jumps induced meaningful improvement in explosive actions, balance, and intermittent endurance capacity. However, combining vertical and horizontal drills seems more advantageous to induce greater performance improvements.

Endurance training at altitude.

Science.gov (United States)

Saunders, Philo U; Pyne, David B; Gore, Christopher J

2009-01-01

Since the 1968 Olympic Games when the effects of altitude on endurance performance became evident, moderate altitude training ( approximately 2000 to 3000 m) has become popular to improve competition performance both at altitude and sea level. When endurance athletes are exposed acutely to moderate altitude, a number of physiological responses occur that can comprise performance at altitude; these include increased ventilation, increased heart rate, decreased stroke volume, reduced plasma volume, and lower maximal aerobic power ((.)Vo(2max)) by approximately 15% to 20%. Over a period of several weeks, one primary acclimatization response is an increase in the volume of red blood cells and consequently of (.)Vo(2max). Altitudes > approximately 2000 m for >3 weeks and adequate iron stores are required to elicit these responses. However, the primacy of more red blood cells for superior sea-level performance is not clear-cut since the best endurance athletes in the world, from Ethiopia (approximately 2000 to 3000 m), have only marginally elevated hemoglobin concentrations. The substantial reduction in (.)Vo(2max) of athletes at moderate altitude implies that their training should include adequate short-duration (approximately 1 to 2 min), high-intensity efforts with long recoveries to avoid a reduction in race-specific fitness. At the elite level, athlete performance is not dependent solely on (.)Vo(2max), and the "smallest worthwhile change" in performance for improving race results is as little as 0.5%. Consequently, contemporary statistical approaches that utilize the concept of the smallest worthwhile change are likely to be more appropriate than conventional statistical methods when attempting to understand the potential benefits and mechanisms of altitude training.

Effects of caffeine ingestion on endurance performance in mentally fatigued individuals.

Science.gov (United States)

Azevedo, Rafael; Silva-Cavalcante, Marcos David; Gualano, Bruno; Lima-Silva, Adriano E; Bertuzzi, Romulo

2016-12-01

To examine the effects of caffeine ingestion on physiological and perceptual responses in mentally fatigued individuals. Eight male physically active subjects completed four cycling constant-workload tests in four experimental conditions at 80 % of maximal power output: control (C), mental fatigue (MF), mental fatigue plus caffeine ingestion (5 mg/kg) (MF-CAF), and mental fatigue plus placebo (MF-PLA). The mental fatigue was induced by a continuous performance task A-X version (AX-CPT). Before and after the AX-CPT, the profile of mood state (POMS) and blood samples for lactate measurement were collected. Oxygen consumption ([Formula: see text]), rating of perceived exertion (RPE), and electromyography (EMG) activity were measured during the cycling test. The time to exhaustion in C, MF, MF-PLA, and MF-CAF were 251 ± 30, 222 ± 23, 248 ± 28, and 285 ± 42 s, respectively. Delta values (corrected by C condition) were higher in MF-CAF than MF (P = 0.031). MF-CAF reported higher Vigor scores when compared with C (P = 0.046) and MF (P = 0.020). RPE at the first minute was significantly higher in MF-PLA than in C (P = 0.050); at the second minute, RPE was higher in MF-PLA than in C (P = 0.049) and MF-CAF (P = 0.048). EMG activity was not different between the conditions. Caffeine ingestion increased approximately 14 % endurance performance after the induction of mental fatigue. This effect was accompanied by a tendency to improvement in mood state (i.e., vigor). Therefore, caffeine ingestion can promote a beneficial effect on endurance performance in mentally fatigued individuals.

Sleep Deprivation Impairs and Caffeine Enhances My Performance, but Not Always Our Performance.

Science.gov (United States)

Faber, Nadira S; Häusser, Jan A; Kerr, Norbert L

2017-02-01

What effects do factors that impair or enhance performance in individuals have when these individuals act in groups? We provide a framework, called the GIE ("Effects of Grouping on Impairments and Enhancements") framework, for investigating this question. As prominent examples for individual-level impairments and enhancements, we discuss sleep deprivation and caffeine. Based on previous research, we derive hypotheses on how they influence performance in groups, specifically process gains and losses in motivation, individual capability, and coordination. We conclude that the effect an impairment or enhancement has on individual-level performance is not necessarily mirrored in group performance: grouping can help or hurt. We provide recommendations on how to estimate empirically the effects individual-level performance impairments and enhancements have in groups. By comparing sleep deprivation to stress and caffeine to pharmacological cognitive enhancement, we illustrate that we cannot readily generalize from group results on one impairment or enhancement to another, even if they have similar effects on individual-level performance.

Shoulder muscle endurance: the development of a standardized and reliable protocol

Directory of Open Access Journals (Sweden)

Roy Jean-Sébastien

2011-01-01

Full Text Available Abstract Background Shoulder muscle fatigue has been proposed as a possible link to explain the association between repetitive arm use and the development of rotator cuff disorders. To our knowledge, no standardized clinical endurance protocol has been developed to evaluate the effects of muscle fatigue on shoulder function. Such a test could improve clinical examination of individuals with shoulder disorders. Therefore, the purpose of this study was to establish a reliable protocol for objective assessment of shoulder muscle endurance. Methods An endurance protocol was developed on a stationary dynamometer (Biodex System 3. The endurance protocol was performed in isotonic mode with the resistance set at 50% of each subject's peak torque as measured for shoulder external (ER and internal rotation (IR. Each subject performed 60 continuous repetitions of IR/ER rotation. The endurance protocol was performed by 36 healthy individuals on two separate occasions at least two days apart. Maximal isometric shoulder strength tests were performed before and after the fatigue protocol to evaluate the effects of the endurance protocol and its reliability. Paired t-tests were used to evaluate the reduction in shoulder strength due to the protocol, while intraclass correlation coefficients (ICC and minimal detectable change (MDC were used to evaluate its reliability. Results Maximal isometric strength was significantly decreased after the endurance protocol (P 0.84. Conclusions Changes in muscular performance observed during and after the muscular endurance protocol suggests that the protocol did result in muscular fatigue. Furthermore, this study established that the resultant effects of fatigue of the proposed isotonic protocol were reproducible over time. The protocol was performed without difficulty by all volunteers and took less than 10 minutes to perform, suggesting that it might be feasible for clinical practice. This protocol could be used to induce

EFFECTIVENESS OF LAND BASED ENDURANCE TRAINING VERSUS AQUATIC BASED ENDURANCE TRAINING ON IMPROVING ENDURANCE IN NORMAL INDIVIDUALS

Directory of Open Access Journals (Sweden)

Sabitha Eunice Regima

2015-06-01

Full Text Available Background: Recently the exercises and fitness professionals have adopted water as an alternative medium for delivering programs to improve fitness and health. When exercise on dry land our skeletal muscular, cardiovascular, respiratory and other body systems are greatly affected by the forces of gravity. When exercise in water, the effects created by the gravitational pull on the body are attenuated. Therefore the aim of this study was to determine the effectiveness of land based endurance training and aquatic based endurance training for enhancing endurance in normal individuals. Methods: An experimental study design with 30 subjects healthy individuals between 20-30 years of both sexes currently were divided equally into 2 groups. Group A underwent land based exercises while Group B underwent aquatic based exercises. The outcome measures consist of RPP (rate pressure product, REC HR (recovery heart rate, RHR (resting heart rate and 6MWD (6 minute walking distance was measured before (pre-training and after four weeks of endurance training. Results: In this study, the mean improvement between the 2 groups of land and aquatic based endurance exercises were tested for significance using a dependent t test. The calculated t value were 43.550, 4.583, 16, 5.870 for RPP, REC HR, RHR, 6MWD for group A respectively. For group B 25.922, 12.762, 27.495,19.236 for RPP, REC HR, RHR, 6MWD for group A respectively with p<0.05. This clearly indicated that both land based exercises and aquatic based exercises will improve cardiovascular endurance significantly and there is no significant difference between land based exercises and aquatic based exercises for enhancing endurance in normal individuals. Conclusion: It is concluded that both land based and aquatic based endurance exercises methods produce equivalent, if not same effect on the enhancement of aerobic endurance. There was no significant difference between these two exercising mediums. Nonetheless

Effects of Exercise Training under Hyperbaric Oxygen on Oxidative Stress Markers and Endurance Performance in Young Soccer Players: A Pilot Study

Directory of Open Access Journals (Sweden)

Carlos Burgos

2016-01-01

Full Text Available The aim of the present study was to determine the effects of three weeks of hyperbaric oxygen (HBO2 training on oxidative stress markers and endurance performance in young soccer players. Participants (18.6±1.6 years were randomized into hyperbaric-hyperoxic (HH training (n=6 and normobaric normoxic (NN training (n=6 groups. Immediately before and after the 5th, 10th, and 15th training sessions, plasma oxidative stress markers (lipid hydroperoxides and uric acid, plasma antioxidant capacity (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid [TROLOX], arterial blood gases, acid-base balance, bases excess (BE, and blood lactate analyses were performed. Before and after intervention, maximal oxygen uptake (VO2max and peak power output (PPO were determined. Neither HH nor NN experienced significant changes on oxidative stress markers or antioxidant capacity during intervention. VO2max and PPO were improved (moderate effect size after HH training. The results suggest that HBO2 endurance training does not increase oxidative stress markers and improves endurance performance in young soccer players. Our findings warrant future investigation to corroborate that HBO2 endurance training could be a potential training approach for highly competitive young soccer players.

Study of speed endurance middle distance runners

Directory of Open Access Journals (Sweden)

R.V. Golovaschenko

2013-12-01

Full Text Available Purpose : To investigate the boost performance speed endurance runners who specialize in middle-distance running . Material and methods : The study involved team members Vinnytsia region in an amount of 44 people, whose average age was 20,2 ± 2,1 years. Classes are held during the 21-day mesocycle, 5 times a week, twice a day. Things were aimed at enhancing the development of indicators of special speed endurance. Results : The dynamics of the running speed of the model segments that characterize speed endurance athletes. Proved that the improved running 400 meter intervals helps reduce travel time competitive distance of 1500 meters. Conclusion : The use of the program contributes to higher speed endurance, which determines the result in the women's 1,500 meters.

The influences of obesity and age on functional performance during intermittent upper extremity tasks.

Science.gov (United States)

Cavuoto, Lora A; Nussbaum, Maury A

2014-01-01

In this study, the main and interactive effects of obesity and age on functional performance were assessed during intermittent exertions involving the upper extremity. The prevalence of obesity has doubled over the past 30 years and this increase is associated with higher health care costs, rates of workplace injury, and lost workdays. Obesity and aging can modify job demands and affect worker capacity in terms of muscular and psychomotor function. However, there is a lack of empirical studies quantifying the work-relevant (or ergonomic) impacts related to task demands, capacities, and their potential imbalance. Eight obese and eight non-obese participants from each of two age groups (18-25 and 50-65 years) completed three endurance tasks involving fixed levels of task demands: hand grip, shoulder flexion, and a simulated assembly task using the upper extremity. Measures of functional performance including endurance, discomfort, motor control, and task performance were recorded for each of the task conditions. Endurance times were ∼60% longer for the non-obese group, and older participants had longer endurance times; however there was no evidence of interactive effects of obesity and age. Obesity also impaired functional performance, as indicated by higher rates of strength loss, increases in discomfort, and declines in task performance. These observed impairments may reflect underlying physiological differences among individuals who are obese, but that are independent of age. Obesity-related impairments may have implications for the design of work duration and demand level to prevent fatigue development for workers who are obese.

Effects of protein in combination with carbohydrate supplements on acute or repeat endurance exercise performance: a systematic review.

Science.gov (United States)

McLellan, Tom M; Pasiakos, Stefan M; Lieberman, Harris R

2014-04-01

Protein supplements are consumed frequently by athletes and recreationally active adults for various reasons, including improved exercise performance and recovery after exercise. Yet, far too often, the decision to purchase and consume protein supplements is based on marketing claims rather than available evidence-based research. The purpose of this review was to provide a systematic and comprehensive analysis of the literature that tested the hypothesis that protein supplements, when combined with carbohydrate, directly enhance endurance performance by sparing muscle glycogen during exercise and increasing the rate of glycogen restoration during recovery. The analysis was used to create evidence statements based on an accepted strength of recommendation taxonomy. English language articles were searched with PubMed and Google Scholar using protein and supplements together with performance, exercise, competition, and muscle, alone or in combination as keywords. Additional articles were retrieved from reference lists found in these papers. Inclusion criteria specified recruiting healthy active adults less than 50 years of age and evaluating the effects of protein supplements in combination with carbohydrate on endurance performance metrics such as time-to-exhaustion, time-trial, or total power output during sprint intervals. The literature search identified 28 articles, of which 26 incorporated test metrics that permitted exclusive categorization into one of the following sections: ingestion during an acute bout of exercise (n = 11) and ingestion during and after exercise to affect subsequent endurance performance (n = 15). The remaining two articles contained performance metrics that spanned both categories. All papers were read in detail and searched for experimental design confounders such as energy content of the supplements, dietary control, use of trained or untrained participants, number of subjects recruited, direct measures of muscle glycogen utilization and

Effect of Progressive Volume-Based Overload During Plyometric Training on Explosive and Endurance Performance in Young Soccer Players.

Science.gov (United States)

Ramírez-Campillo, Rodrigo; Henríquez-Olguín, Carlos; Burgos, Carlos; Andrade, David C; Zapata, Daniel; Martínez, Cristian; Álvarez, Cristian; Baez, Eduardo I; Castro-Sepúlveda, Mauricio; Peñailillo, Luis; Izquierdo, Mikel

2015-07-01

The purpose of the study was to compare the effects of progressive volume-based overload with constant volume-based overload on muscle explosive and endurance performance adaptations during a biweekly short-term (i.e., 6 weeks) plyometric training intervention in young soccer players. Three groups of young soccer players (age 13.0 ± 2.3 years) were divided into: control (CG; n = 8) and plyometric training with (PPT; n = 8) and without (NPPT; n = 8) a progressive increase in volume (i.e., 16 jumps per leg per week, with an initial volume of 80 jumps per leg each session). Bilateral and unilateral horizontal and vertical countermovement jump with arms (CMJA), 20-cm drop jump reactive strength index (RSI20), maximal kicking velocity (MKV), 10-m sprint, change of direction speed (CODS), and Yo-Yo intermittent recovery level 1 test (Yo-Yo IR1) were measured. Although both experimental groups significantly increased CMJA, RSI20, CODS, and endurance performance, only PPT showed a significant improvement in MKV and 10-m sprint time. In addition, only PPT showed a significantly higher performance improvement in jumping, MKV, and Yo-Yo IR1 compared with CG. Also, PPT showed higher meaningful improvement compared with NPPT in all (except 1) jump performance measures. Furthermore, although PPT involved a higher total volume compared with NPPT, training efficiency (i.e., percentage change in performance/total jump volume) was similar between groups. Our results show that PPT and NPPT ensured significant improvement in muscle explosive and endurance performance measures. However, a progressive increase in plyometric training volume seems more advantageous to induce soccer-specific performance improvements.

Study on Endurance and Performance of Impregnated Ruthenium Catalyst for Thruster System.

Science.gov (United States)

Kim, Jincheol; Kim, Taegyu

2018-02-01

Performance and endurance of the Ru catalyst were studied for nitrous oxide monopropellant thruster system. The thermal decomposition of N2O requires a considerably high temperature, which make it difficult to be utilized as a thruster propellant, while the propellant decomposition temperature can be reduced by using the catalyst through the decomposition reaction with the propellant. However, the catalyst used for the thruster was frequently exposed to high temperature and high-pressure environment. Therefore, the state change of the catalyst according to the thruster operation was analyzed. Characterization of catalyst used in the operation condition of the thruster was performed using FE-SEM and EDS. As a result, performance degradation was occurred due to the volatilization of Ru catalyst and reduction of the specific surface area according to the phase change of Al2O3.

Static and Dynamic Handgrip Strength Endurance: Test-Retest Reproducibility.

Science.gov (United States)

Gerodimos, Vassilis; Karatrantou, Konstantina; Psychou, Dimitra; Vasilopoulou, Theodora; Zafeiridis, Andreas

2017-03-01

This study investigated the reliability of static and dynamic handgrip strength endurance using different protocols and indicators for the assessment of strength endurance. Forty young, healthy men and women (age, 18-22 years) performed 2 handgrip strength endurance protocols: a static protocol (sustained submaximal contraction at 50% of maximal voluntary contraction) and a dynamic one (8, 10, and 12 maximal repetitions). The participants executed each protocol twice to assess the test-retest reproducibility. Total work and total time were used as indicators of strength endurance in the static protocol; the strength recorded at each maximal repetition, the percentage change, and fatigue index were used as indicators of strength endurance in the dynamic protocol. The static protocol showed high reliability irrespective of sex and hand for total time and work. The 12-repetition dynamic protocol exhibited moderate-high reliability for repeated maximal repetitions and percentage change; the 8- and 10-repetition protocols demonstrated lower reliability irrespective of sex and hand. The fatigue index was not a reliable indicator for the assessment of dynamic handgrip endurance. Static handgrip endurance can be measured reliably using the total time and total work as indicators of strength endurance. For the evaluation of dynamic handgrip endurance, the 12-repetition protocol is recommended, using the repeated maximal repetitions and percentage change as indicators of strength endurance. Practitioners should consider the static (50% maximal voluntary contraction) and dynamic (12 repeated maximal repetitions) protocols as reliable for the assessment of handgrip strength endurance. The evaluation of static endurance in conjunction with dynamic endurance would provide more complete information about hand function. Copyright © 2017 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Comparison between two types of anaerobic speed endurance training in competitive soccer players

DEFF Research Database (Denmark)

Mohr, Magni; Krustrup, Peter

2016-01-01

The purpose of the present study was to examine the effects of additional in-season speed endurance production versus speed endurance maintenance training regimes on performance in competitive male soccer players. In a randomised controlled trial 18 male sub-elite players were exposed to additional...... during training were higher (psoccer players with superior...... speed endurance production (SEP) or speed endurance maintenance (SEM) training (two additional sessions/wk for 4 weeks) during the competitive season. Players performed the Yo-Yo intermittent recovery level 2 test (YYIR2) and a repeated sprint test (RST) pre- and postintervention. Yo-Yo IR2 performance...

Effect of a moderate caffeine dose on endurance cycle performance and thermoregulation during prolonged exercise in the heat.

Science.gov (United States)

Beaumont, Ross E; James, Lewis J

2017-11-01

This study investigated the influence of a moderate caffeine dose on endurance cycle performance and thermoregulation during prolonged exercise in high ambient temperature. Double-blind cross-over study. Eight healthy, recreationally active males (mean±SD; age: 22±1 years; body mass: 71.1±8.5kg; VO 2peak : 55.9±5.8mLkg -1 min -1 ; W max : 318±37W) completed one VO 2peak test, one familiarisation trial and two experimental trials. After an overnight fast, participants ingested a placebo or a 6mgkg -1 caffeine dose 60min before exercise. The exercise protocol consisted of 60min of cycle exercise at 55% W max , followed by a 30min performance task (total kJ produced) in 30°C and 50% RH. Performance was enhanced (Cohen's d effect size=0.22) in the caffeine trial (363.8±47.6kJ) compared with placebo (353.0±49.0kJ; p=0.004). Caffeine did not influence core (p=0.188) or skin temperature (p=0.577) during exercise. Circulating prolactin (p=0.572), cortisol (p=0.842) and the estimated rates of fat (p=0.722) and carbohydrate oxidation (p=0.454) were also similar between trial conditions. Caffeine attenuated perceived exertion during the initial 60min of exercise (p=0.033), with no difference in thermal stress across trials (p=0.911). Supplementation with 6mgkg -1 caffeine improved endurance cycle performance in a warm environment, without differentially influencing thermoregulation during prolonged exercise at a fixed work-rate versus placebo. Therefore, moderate caffeine doses which typically enhance performance in temperate environmental conditions also appear to benefit endurance performance in the heat. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Red light and the sleep quality and endurance performance of Chinese female basketball players.

Science.gov (United States)

Zhao, Jiexiu; Tian, Ye; Nie, Jinlei; Xu, Jincheng; Liu, Dongsen

2012-01-01

Good sleep is an important recovery method for prevention and treatment of overtraining in sport practice. Whether sleep is regulated by melatonin after red-light irradiation in athletes is unknown. To determine the effect of red light on sleep quality and endurance performance of Chinese female basketball players. Cohort study. Athletic training facility of the Chinese People's Liberation Army and research laboratory of the China Institute of Sport Science. Patients or Other Participants: Twenty athletes of the Chinese People's Liberation Army team (age = 18.60 6 3.60 years) took part in the study. Participants were divided into red-light treatment (n = 10) and placebo (n = 10) groups. The red-light treatment participants received 30 minutes of irradiation from a red-light therapy instrument every night for 14 days. The placebo group did not receive light illumination. The Pittsburgh Sleep Quality Index (PSQI) questionnaire was completed, serum melatonin was assessed, and 12-minute run was performed at preintervention (baseline) and postintervention (14 days). The 14-day whole-body irradiation with red-light treatment improved the sleep, serum melatonin level, and endurance performance of the elite female basketball players (P Sleep Quality Index and serum melatonin levels (r = -0.695, P = .006). Our study confirmed the effectiveness of body irradiation with red light in improving the quality of sleep of elite female basketball players and offered a nonpharmacologic and noninvasive therapy to prevent sleep disorders after training.

Left Ventricular Function After Prolonged Exercise in Equine Endurance Athletes

DEFF Research Database (Denmark)

Flethøj, M.; Schwarzwald, C. C.; Haugaard, M. M.

2016-01-01

Doppler imaging, and two-dimensional speckle tracking. Correlation between echocardiographic variables and cardiac troponin I was evaluated. Results: Early diastolic myocardial velocities decreased significantly in longitudinal (baseline: −17.4 ± 2.4cm/s; end of ride: −15.8 ± 3.2cm/s (P = .013); morning......Background: Prolonged exercise in human athletes is associated with transient impairment of left ventricular (LV) function, known as cardiac fatigue. Cardiac effects of prolonged exercise in horses remain unknown. Objectives :To investigate the effects of prolonged exercise on LV systolic...... and diastolic function in horses. Animals: Twenty-six horses competing in 120–160 km endurance rides. Methods: Cross-sectional field study. Echocardiography was performed before and after rides, and the following morning, and included two-dimensional echocardiography, anatomical M-mode, pulsed-wave tissue...

Combined speed endurance and endurance exercise amplify the exercise-induced PGC-1α and PDK4 mRNA response in trained human muscle

DEFF Research Database (Denmark)

Skovgaard, Casper; Brandt, Nina; Pilegaard, Henriette

2016-01-01

The aim of this study was to investigate the mRNA response related to mitochondrial biogenesis, metabolism, angiogenesis, and myogenesis in trained human skeletal muscle to speed endurance exercise (S), endurance exercise (E), and speed endurance followed by endurance exercise (S + E). Seventeen...... trained male subjects (maximum oxygen uptake (VO2-max): 57.2 ± 3.7 (mean ± SD) mL·min(-1)·kg(-1)) performed S (6 × 30 sec all-out), E (60 min ~60% VO2-max), and S + E on a cycle ergometer on separate occasions. Muscle biopsies were obtained at rest and 1, 2, and 3 h after the speed endurance exercise (S...... and S + E) and at rest, 0, 1, and 2 h after exercise in E In S and S + E, muscle peroxisome proliferator-activated receptor-γ coactivator-1 (PGC-1α) and pyruvate dehydrogenase kinase-4 (PDK4) mRNA were higher (P endurance exercise than at rest. Muscle PGC-1α and PDK4 m...

The metabolic and performance effects of caffeine compared to coffee during endurance exercise.

Science.gov (United States)

Hodgson, Adrian B; Randell, Rebecca K; Jeukendrup, Asker E

2013-01-01

There is consistent evidence supporting the ergogenic effects of caffeine for endurance based exercise. However, whether caffeine ingested through coffee has the same effects is still subject to debate. The primary aim of the study was to investigate the performance enhancing effects of caffeine and coffee using a time trial performance test, while also investigating the metabolic effects of caffeine and coffee. In a single-blind, crossover, randomised counter-balanced study design, eight trained male cyclists/triathletes (Mean ± SD: Age 41 ± 7 y, Height 1.80 ± 0.04 m, Weight 78.9 ± 4.1 kg, VO2 max 58 ± 3 ml • kg(-1) • min(-1)) completed 30 min of steady-state (SS) cycling at approximately 55% VO2max followed by a 45 min energy based target time trial (TT). One hour prior to exercise each athlete consumed drinks consisting of caffeine (5 mg CAF/kg BW), instant coffee (5 mg CAF/kg BW), instant decaffeinated coffee or placebo. The set workloads produced similar relative exercise intensities during the SS for all drinks, with no observed difference in carbohydrate or fat oxidation. Performance times during the TT were significantly faster (~5.0%) for both caffeine and coffee when compared to placebo and decaf (38.35 ± 1.53, 38.27 ± 1.80, 40.23 ± 1.98, 40.31 ± 1.22 min respectively, pperformance times were similar for both caffeine and coffee. Average power for caffeine and coffee during the TT was significantly greater when compared to placebo and decaf (294 ± 21 W, 291 ± 22 W, 277 ± 14 W, 276 ± 23 W respectively, pcaffeine (5 mg/kg/BW) and coffee (5 mg/kg/BW) consumed 1 h prior to exercise can improve endurance exercise performance.

Effects of Cycling vs. Running Training on Endurance Performance in Preparation for Inline Speed Skating.

Science.gov (United States)

Stangier, Carolin; Abel, Thomas; Hesse, Clemens; Claen, Stephanie; Mierau, Julia; Hollmann, Wildor; Strüder, Heiko K

2016-06-01

Winter weather conditions restrict regular sport-specific endurance training in inline speed skating. As a result, this study was designed to compare the effects of cycling and running training programs on inline speed skaters' endurance performance. Sixteen (8 men, 8 women) high-level athletes (mean ± SD 24 ± 8 years) were randomly assigned to 1 of 2 groups (running and cycling). Both groups trained twice a week for 8 weeks, one group on a treadmill and the other on a cycle ergometer. Training intensity and duration was individually calculated (maximal fat oxidation: ∼52% of V[Combining Dot Above]O2peak: 500 kcal per session). Before and after the training intervention, all athletes performed an incremental specific (inline speed skating) and 1 nonspecific (cycling or running) step test according to the group affiliation. In addition to blood lactate concentration, oxygen uptake (V[Combining Dot Above]O2), ventilatory equivalent (VE/V[Combining Dot Above]O2), respiratory exchange ratio (RER), and heart rate were measured. The specific posttest revealed significantly increased absolute V[Combining Dot Above]O2peak values (2.9 ± 0.4, 3.4 ± 0.7, p = 0.01) and submaximal V[Combining Dot Above]O2 values (p ≤ 0.01). VE/V[Combining Dot Above]O2 and RER significantly decreased at maximal (46.6 ± 6.6, 38.5 ± 3.4, p = 0.005; 1.1 ± 0.03, 1.0 ± 0.04, p = 0.001) and submaximal intensities (p ≤ 0.04). None of the analysis revealed a significant group effect (p ≥ 0.15). The results indicate that both cycling vs. running exercise at ∼52% of V[Combining Dot Above]O2peak had a positive effect on the athletes' endurance performance. The increased submaximal V[Combining Dot Above]O2 values indicate a reduction in athletes' inline speed skating technique. Therefore, athletes would benefit from a focus on technique training in the subsequent period.

Endurance training and GH administration in elderly women

DEFF Research Database (Denmark)

Lange, K H; Lorentsen, J; Isaksson, F

2001-01-01

and after completion of the training program. Similarly, no effect on subcutaneous abdominal adipose tissue lipolysis was observed when combining endurance training with rhGH administration. However, in both the placebo and the GH groups, fat oxidation was significantly increased during exercise performed......In the present study, the effect of endurance training alone and endurance training combined with recombinant human growth hormone (rhGH) administration on subcutaneous abdominal adipose tissue lipolysis was investigated. Sixteen healthy women [age 75 +/- 2 yr (mean +/- SE)] underwent a 12-wk...... endurance training program on a cycle ergometer. rhGH was administered in a randomized, double-blinded, placebo-controlled design in addition to the training program. Subcutaneous abdominal adipose tissue lipolysis was estimated by means of microdialysis combined with measurements of subcutaneous abdominal...

Strength, Endurance, Throwing Velocity and in-Water Jump Performance of Elite German Water Polo Players

Directory of Open Access Journals (Sweden)

Zinner Christoph

2015-03-01

Full Text Available The purpose of this study was threefold: 1 to assess the eggbeater kick and throwing performance using a number of water polo specific tests, 2 to explore the relation between the eggbeater kick and throwing performance, and 3 to investigate the relation between the eggbeater kick in the water and strength tests performed in a controlled laboratory setting in elite water polo players. Fifteen male water polo players of the German National Team completed dynamic and isometric strength tests for muscle groups (adductor, abductor, abdominal, pectoralis frequently used during water polo. After these laboratory strength tests, six water polo specific in-water tests were conducted. The eggbeater kick assessed leg endurance and agility, maximal throwing velocity and jump height. A 400 m test and a sprint test examined aerobic and anaerobic performance. The strongest correlation was found between jump height and arm length (p < 0.001, r = 0.89. The laboratory diagnostics of important muscles showed positive correlations with the results of the in-water tests (p < 0.05, r = 0.52-0.70. Muscular strength of the adductor, abdominal and pectoralis muscles was positively related to in-water endurance agility as assessed by the eggbeater kick (p < 0.05; r = 0.53-0.66. Findings from the current study emphasize the need to assess indices of water polo performance both in and out of the water as well as the relation among these parameters to best assess the complex profile of water polo players.

Effects of a concurrent strength and endurance training on running performance and running economy in recreational marathon runners.

Science.gov (United States)

Ferrauti, Alexander; Bergermann, Matthias; Fernandez-Fernandez, Jaime

2010-10-01

The purpose of this study was to investigate the effects of a concurrent strength and endurance training program on running performance and running economy of middle-aged runners during their marathon preparation. Twenty-two (8 women and 14 men) recreational runners (mean ± SD: age 40.0 ± 11.7 years; body mass index 22.6 ± 2.1 kg·m⁻²) were separated into 2 groups (n = 11; combined endurance running and strength training program [ES]: 9 men, 2 women and endurance running [E]: 7 men, and 4 women). Both completed an 8-week intervention period that consisted of either endurance training (E: 276 ± 108 minute running per week) or a combined endurance and strength training program (ES: 240 ± 121-minute running plus 2 strength training sessions per week [120 minutes]). Strength training was focused on trunk (strength endurance program) and leg muscles (high-intensity program). Before and after the intervention, subjects completed an incremental treadmill run and maximal isometric strength tests. The initial values for VO2peak (ES: 52.0 ± 6.1 vs. E: 51.1 ± 7.5 ml·kg⁻¹·min⁻¹) and anaerobic threshold (ES: 3.5 ± 0.4 vs. E: 3.4 ± 0.5 m·s⁻¹) were identical in both groups. A significant time × intervention effect was found for maximal isometric force of knee extension (ES: from 4.6 ± 1.4 to 6.2 ± 1.0 N·kg⁻¹, p marathon running velocities (2.4 and 2.8 m·s⁻¹) and submaximal blood lactate thresholds (2.0, 3.0, and 4.0 mmol·L⁻¹). Stride length and stride frequency also remained unchanged. The results suggest no benefits of an 8-week concurrent strength training for running economy and coordination of recreational marathon runners despite a clear improvement in leg strength, maybe because of an insufficient sample size or a short intervention period.

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

DEFF Research Database (Denmark)

Rinnov, Anders; Yfanti, Christina; Nielsen, Søren

2014-01-01

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

Nutrition for endurance sports: marathon, triathlon, and road cycling.

Science.gov (United States)

Jeukendrup, Asker E

2011-01-01

Endurance sports are increasing in popularity and athletes at all levels are looking for ways to optimize their performance by training and nutrition. For endurance exercise lasting 30 min or more, the most likely contributors to fatigue are dehydration and carbohydrate depletion, whereas gastrointestinal problems, hyperthermia, and hyponatraemia can reduce endurance exercise performance and are potentially health threatening, especially in longer events (>4 h). Although high muscle glycogen concentrations at the start may be beneficial for endurance exercise, this does not necessarily have to be achieved by the traditional supercompensation protocol. An individualized nutritional strategy can be developed that aims to deliver carbohydrate to the working muscle at a rate that is dependent on the absolute exercise intensity as well as the duration of the event. Endurance athletes should attempt to minimize dehydration and limit body mass losses through sweating to 2-3% of body mass. Gastrointestinal problems occur frequently, especially in long-distance races. Problems seem to be highly individual and perhaps genetically determined but may also be related to the intake of highly concentrated carbohydrate solutions, hyperosmotic drinks, as well as the intake of fibre, fat, and protein. Hyponatraemia has occasionally been reported, especially among slower competitors with very high intakes of water or other low sodium drinks. Here I provide a comprehensive overview of recent research findings and suggest several new guidelines for the endurance athlete on the basis of this. These guidelines are more detailed and allow a more individualized approach.

Memory for Public Events in Mild Cognitive Impairment and Alzheimer's Disease: The Importance of Rehearsal.

Science.gov (United States)

Langlois, Roxane; Joubert, Sven; Benoit, Sophie; Dostie, Valérie; Rouleau, Isabelle

2016-01-01

Ribot's law refers to the better preservation of remote memories compared with recent ones that presumably characterizes retrograde amnesia. Even if Ribot-type temporal gradient has been extensively studied in retrograde amnesia, particularly in Alzheimer's disease (AD), this pattern has not been consistently found. One explanation for these results may be that rehearsal frequency rather than remoteness accounts for the better preservation of these memories. Thus, the aim of present study was to address this question by studying retrograde semantic memory in subjects with amnestic mild cognitive impairment (aMCI) (n = 20), mild AD (n = 20) and in healthy older controls (HC; n = 19). In order to evaluate the impact of repetition as well as the impact of remoteness, we used a test assessing memory for enduring and transient public events that occurred in the recent and remote past. Results show no clear temporal gradient across time periods (1960-1975; 1976-1990; 1991-2005; 2006-2011), but a better performance was observed in all three groups for enduring compared with transient events. Moreover, although deficits were globally found in both patients groups compared with HC, more specific analyses revealed that aMCI patients were only impaired on transient events while AD patients were impaired on both transient and enduring events. Exploratory analyses also revealed a tendency suggesting preservation of remote transient events in aMCI. These findings are discussed with regards to memory consolidation models.

Combined strength and endurance training in competitive swimmers.

Science.gov (United States)

Aspenes, Stian; Kjendlie, Per-Ludvik; Hoff, Jan; Helgerud, Jan

2009-01-01

A combined intervention of strength and endurance training is common practice in elite swimming training, but the scientific evidence is scarce. The influences between strength and endurance training have been investigated in other sports but the findings are scattered. Some state the interventions are negative to each other, some state there is no negative relationship and some find bisected and supplementary benefits from the combination when training is applied appropriately. The aim of this study was to investigate the impact of a combined intervention among competitive swimmers. 20 subjects assigned to a training intervention group (n = 11) or a control group (n = 9) from two different teams completed the study. Anthropometrical data, tethered swimming force, land strength, performance in 50m, 100m and 400m, work economy, peak oxygen uptake, stroke length and stroke rate were investigated in all subjects at pre- and post-test. A combined intervention of maximal strength and high aerobic intensity interval endurance training 2 sessions per week over 11 weeks in addition to regular training were used, while the control group continued regular practice with their respective teams. The intervention group improved land strength, tethered swimming force and 400m freestyle performance more than the control group. The improvement of the 400m was correlated with the improvement of tethered swimming force in the female part of the intervention group. No change occurred in stroke length, stroke rate, performance in 50m or 100m, swimming economy or peak oxygen uptake during swimming. Two weekly dry-land strength training sessions for 11 weeks increase tethered swimming force in competitive swimmers. This increment further improves middle distance swimming performance. 2 weekly sessions of high- intensity interval training does not improve peak oxygen uptake compared with other competitive swimmers. Key pointsTwo weekly sessions of dry land strength training improves the

Reliability and validity of a low load endurance strength test for upper and lower extremities in patients with fibromyalgia.

Science.gov (United States)

Munguía-Izquierdo, Diego; Legaz-Arrese, Alejandro

2012-11-01

, respectively, was required for the differences to be considered as substantial clinical change. Patients with FS showed impaired endurance strength to low loads performance when compared with the general population. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Índices fisiológicos associados com a "performance" aeróbia em corredores de "endurance": efeitos da duração da prova Índices fisiológicos asociados a la "performance" aerobia en competidores de "endurance": efectos de la duración de la prueba Physiological indexes associated with aerobic performance in endurance runners: effects of race duration

Directory of Open Access Journals (Sweden)

Benedito Sérgio Denadai

2004-10-01

Full Text Available O objetivo deste estudo foi analisar a validade do consumo máximo de oxigênio (VO2max, da velocidade correspondente ao VO2max (vVO2max, do tempo de exaustão na vVO2max (Tlim, da economia de corrida (EC e do limiar anaeróbio (LAn para a predição da performance de atletas de endurance. Quatorze corredores de endurance (33,4 ± 4,4 anos; 62,7 ± 4,3kg; 166,1 ± 5,0cm; VO2max = 60,4 ± 5,9ml.kg-1.min-1 realizaram os seguintes testes: a competição simulada nas distâncias de 1.500 e 5.000m. e; b testes de laboratório para a determinação do VO2max, vVO2max, EC, LAn e Tlim na intensidades de 100% vVO2max. As velocidades (km/h da vVO2max (18,7 ± 0,8, LAn (17,3 ± 1,1 v1.500m (19,9 ± 0,8 e v5.000m (17,9 ± 0,9 foram significantemente diferentes. A regressão múltipla stepwise revelou que o LAn foi o único preditor da performance da v5.000m, explicando 50% da variação desta performance. Para a v1.500m, o Tlim e a vVO2max explicaram 88% da variação da performance. Com base em nossos resultados, pode-se concluir que a validade dos índices fisiológicos (VO2max, vVO2max, Tlim, EC e LAn, para a predição da performance aeróbia de atletas de endurance, é dependente da distância da prova (1.500 x 5.000m analisada.El objetivo de este estudio fue analizar la validez del consumo máximo de oxígeno (VO2max, de la velocidad correspondiente al VO2max (vVO2max, del tiempo de exaustión en la vVO2max (Tlim, de la economía de la carrera (EC y del umbral anaeróbico (LAn para predecir la performance de atletas de endurance. Catorce competidores de endurance (33,4 ± 4,4 años; 62,7 ± 4,3kg; 166,1 ± 5,0cm; VO2max = 60,4 ± 5,9ml.kg-1.min-1 realizaron las siguientes pruebas: a competición simulada en las distancias de 1.500 y 5.000m. e; b pruebas de laboratorio para la determinación del VO2max, vVO2max, EC, LAn y Tlim en la intensidad del 100% vVO2max. Las velocidades (km/h de la vVO2max (18,7 ± 0,8, LAn (17,3 ± 1,1 v1.500m (19,9 ± 0,8 y v5

Effect of thyme extract supplementation on lipid peroxidation, antioxidant capacity, PGC-1α content and endurance exercise performance in rats.

Science.gov (United States)

Khani, Mostafa; Motamedi, Pezhman; Dehkhoda, Mohammad Reza; Dabagh Nikukheslat, Saeed; Karimi, Pouran

2017-01-01

Athletes have a large extent of oxidant agent production. In the current study, we aimed to determine the influence of thyme extract on the endurance exercise performance, mitochondrial biogenesis, and antioxidant status in rats. Twenty male Wistar rats were randomly divided into two groups receiving either normal drinking water (non-supplemented group, n  = 10) or thyme extract, 400 mg/kg, (supplemented group, n  = 10). Rats in both groups were subjected to endurance treadmill training (27 m/min, 10% grade, 60 min, and 5 days/week for 8 weeks). Finally, to determine the endurance capacity, time to exhaustion treadmill running at 36 m/min speed was assessed. At the end of the endurance capacity test, serum and soleus muscle samples were collected and their superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity, as well as malondialdehyde (MDA) concentration were measured. Protein expression of PGC-1α, as a marker of mitochondrial biogenesis, was also determined in the soleus muscle tissue by immunoblotting assay. Findings revealed that the exhaustive running time in the treatment group was significantly ( p  extract supplemented group (t 18  = 8.11, p  antioxidant capacity between groups. Furthermore, thyme supplementation significantly ( p  extract supplementation increased endurance exercise tolerance in intact animals, although decrease of oxidative stress and regulation of the PGC-1α protein expression are not considered as underlying molecular mechanisms.

A structural equation model of the relationship between muscle strength, balance performance, walking endurance and community integration in stroke survivors.

Directory of Open Access Journals (Sweden)

P W H Kwong

Full Text Available To use structural equation modelling (SEM to determine (1 the direct and indirect associations of strength of paretic lower limb muscles with the level of community integration, and (2 the direct association of walking endurance and balance performance with the level of community integration in community-dwelling stroke survivors.In this cross-sectional study of 105 stroke survivors, the Subjective Index of Physical and Social Outcome (SIPSO was used to measure the level of community integration. Lower-limb strength measures included isometric paretic ankle strength and isokinetic paretic knee peak torque. The Berg Balance Scale (BBS and the 6-minute walk test (6MWT were used to evaluate balance performance and walking endurance, respectively.SEM revealed that the distance walked on the 6MWT had the strongest direct association with the SIPSO score (β = 0.41, p <0.001. An increase of one standard deviation in the 6MWT distance resulted in an increase of 0.41 standard deviations in the SIPSO score. Moreover, dorsiflexion strength (β = 0.18, p = 0.044 and the BBS score (β = 0.21, p = 0.021 had direct associations with the SIPSO score.The results of the proposed model suggest that rehabilitation training of community-dwelling stroke survivors could focus on walking endurance, balance performance and dorsiflexor muscle strengthening if the aim is to augment the level of community integration.

CAFFEINE INTAKE ENHANCES ENDURANCE PERFORMANCE IN SUB-ELITE BUT NOT IN ELITE ATHLETES

Directory of Open Access Journals (Sweden)

Ondřej Smolka

2015-01-01

Full Text Available The aim of our contribution is to evaluate the influence of caffeine (CAF ingestion on maximal power output (MPO during endurance performance. Two groups of men – 10 sub-elite cyclists and 8 elite cyclists completed a randomized, crossover, double-blind study. Over the course of three days participants completed three identical experimental tests (60min cycling time trial on 70 % VO2max followed by test to exhaustion. Three experimental meals - a combination of 500ml water, a gel supplement and a specific dose of CAF: a placebo (PLA, no caffeine, CAF2 (2 mg / kg body weight (BW and CAF7 (7 mg / kg BW were administered 45min prior to the start of the experimental tests. Subjective RPE values were determined using the Borg 20-category scale. The results show significant differences between MPOPLA and MPOCAF7 and between MPOCAF2 and MPOCAF7 with p = 0.018 and p = 0.019, respectively, in the sub-elite cyclists group only. The mean MPO during experimental test in sub-elite cyclists, but not in elite cyclists, was significantly enhanced following caffeine ingestion (p = 0.05. These findings indicate that caffeine intake at recommended levels is not associated with improved performance in a professional level cyclist. The results of the comparison of the experimental situations using the Borg scale are not persuasive. We found a significant difference (0.008356 between the PLA and CAF2 experimental measurements (p < 0.05. The level of substantive significance was assessed using Cohen’s coefficient effect and only a small “size of effect” (0.19 was found. It is therefore not possible to determine whether the Borg scale might be used to define the effects of caffeine ingestion on endurance performance, due to the multifactorial effects of caffeine.

Effect of increased and maintained frequency of speed endurance training on performance and muscle adaptations in runners

DEFF Research Database (Denmark)

Skovgaard, Casper; Almquist, Nicki Winfield; Bangsbo, Jens

2017-01-01

The aim of the study was, in runners accustomed to speed endurance training (SET), to examine the effect of increased and maintained frequency of SET on performance and muscular adaptations. After familiarization (FAM) to SET, eighteen male (n=14) and female (n=4) runners (VO2-max: 57.3±3.4 ml·mi...

CEPRAM: Compression for Endurance in PCM RAM

OpenAIRE

González Alberquilla, Rodrigo; Castro Rodríguez, Fernando; Piñuel Moreno, Luis; Tirado Fernández, Francisco

2017-01-01

We deal with the endurance problem of Phase Change Memories (PCM) by proposing Compression for Endurance in PCM RAM (CEPRAM), a technique to elongate the lifespan of PCM-based main memory through compression. We introduce a total of three compression schemes based on already existent schemes, but targeting compression for PCM-based systems. We do a two-level evaluation. First, we quantify the performance of the compression, in terms of compressed size, bit-flips and how they are affected by e...

Performance and endurance of a PEMFC operated with synthetic reformate fuel feed

Energy Technology Data Exchange (ETDEWEB)

Sishtla, C; Koncar, G; Platon, R [Institute of Gas Technology, Des Plaines, IL (United States); Gamburzev, S; Appleby, A J [Texas Engineering Experimental Station, Texas A and M Univ. System, College Station, TX (United States). Center for Electrochemical Systems and Hydrogen Research; Velev, O A [AeroVironment, Inc., Monrovia, CA (United States)

1998-03-15

Widespread implementation of polymer electrolyte membrane fuel cell (PEMFC) powerplants for stationary and vehicular applications will be dependent in the near future on using readily available hydrocarbon fuels as the source of the hydrogen fuel. Methane and propane are ideal fuels for stationary applications, while methanol, gasoline, and diesel fuel are better suited for vehicular applications. Various means of fuel processing are possible to produce a gaseous fuel containing H{sub 2}, CO{sub 2} and CO. CO is a known electrocatalyst poison and must be reduced to low (10`s) ppm levels and CO{sub 2} is said to cause additional polarization effects. Even with no CO in the feed gas a H{sub 2}/CO{sub 2}/H{sub 2}O gas mixture will form some CO. Therefore, as a first step of developing a PEMFC that can operate for thousands of hours using a reformed fuel, we used an anode gas feed of 80% H{sub 2} and 20% CO{sub 2} to simulate the reforming of CH{sub 4}. To investigate the effect of reformate on cell performance and endurance, a single cell with an active area of 58 cm{sup 2} was assembled with a membrane electrode assembly (MEA) furnished by Texas A and M University using IGT`s internally manifolded heat exchange (IMHEX{sup TM}) design configuration. The MEA consisted of a Nafion 112 membrane with anode and cathode Pt catalyst loadings of 0.26 and 1.46 mg/cm{sup 2}, respectively. The cell was set to operate on a synthetic reformate - air at 60 C and 1 atm and demonstrated over 5000 h of endurance with a decay rate of less than 1%/1000 h of operation. The cell also underwent four successful thermal cycles with no appreciable loss in performance. The stable performance is attributed to a combination of the IGT IMHEX plate design with its inherent uniform gas flow distribution across the entire active area and MEA quality. The effects of temperature, gas composition, fuel utilization (stoics) and thermal cycle on cell performance are described. (orig.)

Sympatho-adrenergic activation by endurance exercise: Effect on metanephrines spillover and its role in predicting athlete's performance.

Science.gov (United States)

Danese, Elisa; Tarperi, Cantor; Salvagno, Gian Luca; Guzzo, Alessandra; Sanchis-Gomar, Fabian; Festa, Luca; Bertinato, Luciano; Montagnana, Martina; Schena, Federico; Lippi, Giuseppe

2018-03-20

The sympatho-adrenergic activation during exercise is implicated in many cardiovascular respiratory and metabolic adaptations which have been thought to partially explain the different levels of performance observed between trained and untrained subjects. To date, no evidence exists about the association between competition performance and markers of "acute stress response". We designed this study to investigate; (i) the acute sympatho-adrenergic activation during endurance exercise in recreational runners by measuring plasma levels of free metanephrine (MN) and normethanephrine (NMN) before and after a half-marathon run; (ii) the association between the metanephrines levels and the running time. 26 amateur runners (15 males, 11 females) aged 30 to 63 years were enrolled. The quantification of MN and NMN was performed by LC-MS/MS. Anthropometric ergonomic and routine laboratory data were recorded. Statistical analyses included paired T -test, univariate and multivariate regressions. The post-run values of MN and NMN displayed a nearly 3.5 and 7 fold increase respectively compared to the baseline values ( p performance. No correlations were found for MN values. NMN is a reliable marker of sympatho-adrenergic activation by exercise and can predict endurance performance in the individual athlete. Adaptation phenomenon occurring not only in the adrenal medulla might represent the biological mechanism underlying this association. Further studies on sympatho-adrenergic activation, competition performance and training status should contemplate the measurement of these metabolites instead of their unstable precursors.

Caffeine withdrawal and high-intensity endurance cycling performance.

Science.gov (United States)

Irwin, Christopher; Desbrow, Ben; Ellis, Aleisha; O'Keeffe, Brooke; Grant, Gary; Leveritt, Michael

2011-03-01

In this study, we investigated the impact of a controlled 4-day caffeine withdrawal period on the effect of an acute caffeine dose on endurance exercise performance. Twelve well-trained and familiarized male cyclists, who were caffeine consumers (from coffee and a range of other sources), were recruited for the study. A double-blind placebo-controlled cross-over design was employed, involving four experimental trials. Participants abstained from dietary caffeine sources for 4 days before the trials and ingested capsules (one in the morning and one in the afternoon) containing either placebo or caffeine (1.5 mg · kg(-1) body weight · day(-1)). On day 5, capsules containing placebo or caffeine (3 mg · kg(-1) body weight) were ingested 90 min before completing a time trial, equivalent to one hour of cycling at 75% peak sustainable power output. Hence the study was designed to incorporate placebo-placebo, placebo-caffeine, caffeine-placebo, and caffeine-caffeine conditions. Performance time was significantly improved after acute caffeine ingestion by 1:49 ± 1:41 min (3.0%, P = 0.021) following a withdrawal period (placebo-placebo vs. placebo-caffeine), and by 2:07 ± 1:28 min (3.6%, P = 0.002) following the non-withdrawal period (caffeine-placebo vs. caffeine-caffeine). No significant difference was detected between the two acute caffeine trials (placebo-caffeine vs. caffeine-caffeine). Average heart rate throughout exercise was significantly higher following acute caffeine administration compared with placebo. No differences were observed in ratings of perceived exertion between trials. A 3 mg · kg(-1) dose of caffeine significantly improves exercise performance irrespective of whether a 4-day withdrawal period is imposed on habitual caffeine users.

Adaptations to speed endurance training in highly trained soccer players

DEFF Research Database (Denmark)

Nyberg, Michael Permin; Fiorenza, Matteo; Lund, Anders

2016-01-01

PURPOSE: The present study examined whether a period of additional speed endurance training would improve intense intermittent exercise performance in highly trained soccer players during the season and whether the training changed aerobic metabolism and the level of oxidative enzymes in type I...... and II muscle fibers. METHODS: During the last nine weeks of the season, thirteen semi-professional soccer players performed additional speed endurance training sessions consisting of 2-3 sets of 8 - 10 repetitions of 30 m sprints with 10 s of passive recovery (SET). Before and after SET, subjects...... in type I and II fibers did not change. CONCLUSION: In highly trained soccer players, additional speed endurance training is associated with an improved ability to perform repeated high-intensity work. To what extent the training-induced changes in V˙O2 kinetics and mechanical efficiency in type I fibers...

Vitamins and endurance training. Food for running or faddish claims?

Science.gov (United States)

van der Beek, E J

1985-01-01

The inter-relationship of food and physical performance, food is considered as a conglomerate of nutrients and man is depicted as a kind of organic pudding. This 'machine' concept of human performance in combination with the mysticism surrounding vitamins, has led to the faddish belief that additional vitamins are necessary to improve physical performance by means of supercharging the metabolic processes in the body. Various vitamins and their dietary recommendations as well as the indicators for vitamin status are discussed. It is concluded that a marginal or subclinical deficiency state can be defined as an intermediate between optimal vitamin status and frank clinical deficiency. Marginal deficiency is characterised by biochemical values deviating from statistically derived reference limits as well as the absence of clinical signs and symptoms of vitamin deficiency. Besides the static, mostly biochemical, indicators of vitamin status, more functional indicators are considered, among them work capacity. An extensive historical review on depletion studies, epidemiological surveys and supplementation studies is presented. It is concluded that a restricted intake of some B-complex vitamins-individually and in combination-of approximately less than 35 to 45% of the recommended dietary allowance may lead to decreased endurance capacity within a few weeks. Studies on ascorbic acid (vitamin C) depletion and fat-soluble vitamin A deficiency have noted no decrease of endurance capacity. However, in a few recent epidemiological surveys, biochemical vitamin C deficiency was actually shown to decrease aerobic power. Although the general conclusion is that a reduced water-soluble vitamin intake decreases endurance capacity, it is believed that further controlled experimentation is needed with B-complex vitamins and vitamin C individually. Furthermore, usually employed reference limits for vitamins need reappraisal translating them into impairment limits. With respect to the

Mixed maximal and explosive strength training in recreational endurance runners.

Science.gov (United States)

Taipale, Ritva S; Mikkola, Jussi; Salo, Tiina; Hokka, Laura; Vesterinen, Ville; Kraemer, William J; Nummela, Ari; Häkkinen, Keijo

2014-03-01

Supervised periodized mixed maximal and explosive strength training added to endurance training in recreational endurance runners was examined during an 8-week intervention preceded by an 8-week preparatory strength training period. Thirty-four subjects (21-45 years) were divided into experimental groups: men (M, n = 9), women (W, n = 9), and control groups: men (MC, n = 7), women (WC, n = 9). The experimental groups performed mixed maximal and explosive exercises, whereas control subjects performed circuit training with body weight. Endurance training included running at an intensity below lactate threshold. Strength, power, endurance performance characteristics, and hormones were monitored throughout the study. Significance was set at p ≤ 0.05. Increases were observed in both experimental groups that were more systematic than in the control groups in explosive strength (12 and 13% in men and women, respectively), muscle activation, maximal strength (6 and 13%), and peak running speed (14.9 ± 1.2 to 15.6 ± 1.2 and 12.9 ± 0.9 to 13.5 ± 0.8 km Ł h). The control groups showed significant improvements in maximal and explosive strength, but Speak increased only in MC. Submaximal running characteristics (blood lactate and heart rate) improved in all groups. Serum hormones fluctuated significantly in men (testosterone) and in women (thyroid stimulating hormone) but returned to baseline by the end of the study. Mixed strength training combined with endurance training may be more effective than circuit training in recreational endurance runners to benefit overall fitness that may be important for other adaptive processes and larger training loads associated with, e.g., marathon training.

Locomotion characteristics and match-induced impairments in physical performance in male elite team handball players.

Science.gov (United States)

Michalsik, L B; Aagaard, P; Madsen, K

2013-07-01

The purpose of this study was to determine the physical demands and match-induced impairments in physical performance in male elite Team Handball (TH) players in relation to playing position. Male elite TH field players were closely observed during 6 competitive seasons. Each player (wing players: WP, pivots: PV, backcourt players: BP) was evaluated during match-play using video recording and subsequently performing locomotion match analysis. A total distance of 3 627±568 m (group means±SD) was covered per match with a total effective playing time (TPT) of 53:51±5:52 min:s, while full-time players covered 3 945±538 m. The mean speed was 6.40±1.01 km · h - 1. High-intensity running constituted only 1.7±0.9% of TPT per match corresponding to 7.9±4.9% of the total distance covered. An average of 1 482.4±312.6 activity changes per player (n=82) with 53.2±14.1 high-intensity runs were observed per match. Total distance covered was greater in BP (3 765±532 m) and WP (3 641±501 m) than PV (3 295±495 m) (pteam sport that comprises several types of movement categories, which during match-play place moderate-to-high demands on intermittent endurance running capacity and where the amount of high-intensity running may be high during brief periods of the match. Signs of fatigue-related changes were observed in terms of temporary impaired physical performance, since the amount of high-intensity running was reduced in the second half. Notably, physical demands differed between playing positions, with WP demonstrating a more intensive activity pattern than BP and PV, respectively. © Georg Thieme Verlag KG Stuttgart · New York.

Mild Cognitive Impairment Status and Mobility Performance

DEFF Research Database (Denmark)

Pedersen, Mette; Holt, Nicole E; Grande, Laura

2014-01-01

: An analysis was conducted on baseline data from the Boston Rehabilitative Impairment Study in the Elderly study, a cohort study of 430 primary care patients aged 65 or older. Neuropsychological tests identified participants with MCI and further subclassified those with impairment in memory domains (a......BACKGROUND: The prevalence of mild cognitive impairment (MCI) and mobility limitations is high among older adults. The aim of this study was to investigate the association between MCI status and both performance-based and self-report measures of mobility in community-dwelling older adults. METHODS...

Comparison between two types of anaerobic speed endurance training in competitive soccer players

Directory of Open Access Journals (Sweden)

Mohr Magni

2016-06-01

Full Text Available The purpose of the present study was to examine the effects of additional in-season speed endurance production versus speed endurance maintenance training regimes on performance in competitive male soccer players. In a randomised controlled trial 18 male sub-elite players were exposed to additional speed endurance production (SEP or speed endurance maintenance (SEM training (two additional sessions/wk for 4 weeks during the competitive season. Players performed the Yo-Yo intermittent recovery level 2 test (YYIR2 and a repeated sprint test (RST pre- and post-intervention. Yo-Yo IR2 performance increased (p<0.001 by 50 ± 8% and 26 ± 5% in SEP and SEM, respectively, with greater (p=0.03 improvement in SEP. RST performance improved by 2.1 ± 0.3% and 1.3 ± 0.4% in SEP and SEM, respectively, while the RST fatigue index decreased (4.4 ± 0.8 to 3.4 ± 0.5%; p<0.04 in SEP only. Peak and average speed during training were higher (p<0.001 in SEP than in SEM (24.5 ± 0.3 vs 19.2 ± 0.3 and 15.5 ± 0.1 km·h-1 vs 9.4 ± 0.1 km·h-1. Additional in-season anaerobic speed endurance production and maintenance training improves high-intensity exercise performance in competitive soccer players with superior effects of speed endurance production training.

Prevalence in running events and running performance of endurance runners following a vegetarian or vegan diet compared to non-vegetarian endurance runners: the NURMI Study.

Science.gov (United States)

Wirnitzer, Katharina; Seyfart, Tom; Leitzmann, Claus; Keller, Markus; Wirnitzer, Gerold; Lechleitner, Christoph; Rüst, Christoph Alexander; Rosemann, Thomas; Knechtle, Beat

2016-01-01

Beneficial and detrimental effects of various vegetarian and vegan diets on the health status are well known. Considering the growing background numbers of vegetarians and vegans, the number of vegetarian and vegan runners is likely to rise, too. Therefore, the Nutrition and Running High Mileage (NURMI) Study was designed as a comparative study to investigate the prevalence of omnivores, vegetarians, and vegans in running events and to detect potential differences in running performance comparing these three subgroups. The NURMI Study will be conducted in three steps following a cross-sectional design. Step 1 will determine epidemiological aspects of endurance runners (any distance) using a short standardized questionnaire. Step 2 will investigate dietary habits and running history from eligible participants (capable of running a half-marathon at least) using an extended standardized questionnaire. Step 3 will collect data after a running event on finishing time and final ranking as well as a post-race rating of perceived exertion, mood status, nutrient and fluid intake during the race. Our study will provide a major contribution to overcome the lack of data on the prevalence and running performance of vegetarian and vegan runners in endurance running events. We estimate the prevalence of vegetarians and vegans participating in a running event to be less compared to the respective proportion of vegetarians and vegans to the general population. Furthermore we will validate the subject's self-assessment of their respective diet. This comparative study may identify possible effects of dietary behavior on running performance und may detect possible differences between the respective subgroups: omnivorous, vegetarian and vegan runners. Trial registration Current controlled trials, ISRCTN73074080.

Individual responses to combined endurance and strength training in older adults.

Science.gov (United States)

Karavirta, Laura; Häkkinen, Keijo; Kauhanen, Antti; Arija-Blázquez, Alfredo; Sillanpää, Elina; Rinkinen, Niina; Häkkinen, Arja

2011-03-01

A combination of endurance and strength training is generally used to seek further health benefits or enhanced physical performance in older adults compared with either of the training modes alone. The mean change within a training group, however, may conceal a wide range of individual differences in the responses. The purpose, therefore, was to examine the individual trainability of aerobic capacity and maximal strength, when endurance and strength training are performed separately or concurrently. For this study, 175 previously untrained volunteers, 89 men and 86 women between the ages of 40 and 67 yr, completed a 21-wk period of either strength training (S) twice a week, endurance training (E) twice a week, combined training (ES) four times per week, or served as controls. Training adaptations were quantified as peak oxygen uptake (VO2peak) in a bicycle ergometer test to exhaustion and maximal isometric bilateral leg extension force (MVC) in a dynamometer. A large range in training responses, similar to endurance or strength training alone, was also observed with combined endurance and strength training in both ΔVO2peak (from -8% to 42%) and ΔMVC (from -12% to 87%). There were no significant correlations between the training responses in VO2peak and MVC in the E, S, or especially in the ES group, suggesting that the same subjects did not systematically increase both aerobic capacity and maximal strength. The goal of combined endurance and strength training--increasing both aerobic capacity and maximal strength simultaneously--was only achieved by some of the older subjects. New means are needed to personalize endurance, strength, and especially combined endurance and strength training programs for optimal individual adaptations.

Calcaneus length determines running economy: implications for endurance running performance in modern humans and Neandertals.

Science.gov (United States)

Raichlen, David A; Armstrong, Hunter; Lieberman, Daniel E

2011-03-01

The endurance running (ER) hypothesis suggests that distance running played an important role in the evolution of the genus Homo. Most researchers have focused on ER performance in modern humans, or on reconstructing ER performance in Homo erectus, however, few studies have examined ER capabilities in other members of the genus Homo. Here, we examine skeletal correlates of ER performance in modern humans in order to evaluate the energetics of running in Neandertals and early Homo sapiens. Recent research suggests that running economy (the energy cost of running at a given speed) is strongly related to the length of the Achilles tendon moment arm. Shorter moment arms allow for greater storage and release of elastic strain energy, reducing energy costs. Here, we show that a skeletal correlate of Achilles tendon moment arm length, the length of the calcaneal tuber, does not correlate with walking economy, but correlates significantly with running economy and explains a high proportion of the variance (80%) in cost between individuals. Neandertals had relatively longer calcaneal tubers than modern humans, which would have increased their energy costs of running. Calcaneal tuber lengths in early H. sapiens do not significantly differ from those of extant modern humans, suggesting Neandertal ER economy was reduced relative to contemporaneous anatomically modern humans. Endurance running is generally thought to be beneficial for gaining access to meat in hot environments, where hominins could have used pursuit hunting to run prey taxa into hyperthermia. We hypothesize that ER performance may have been reduced in Neandertals because they lived in cold climates. Copyright © 2011 Elsevier Ltd. All rights reserved.

EFFECTS OF PALM VITAMIN E SUPPLEMENTATION ON EXERCISE-INDUCED OXIDATIVE STRESS AND ENDURANCE PERFORMANCE IN THE HEAT

Directory of Open Access Journals (Sweden)

Chen Chee Keong

2006-12-01

Full Text Available This study investigates the effects of tocotrienol-rich palm vitamin E supplementation on exercise-induced lipid peroxidation and endurance performance in the heat. In a double blind, cross-over study, eighteen healthy, male recreational athletes completed two endurance running trials, until exhaustion, on a motorized treadmill at 70% VO2max on two separate occasions following a 6-week supplementation regimen of either tocotrienol-rich palm vitamin E (E or placebo (P. Both trials were conducted in the heat (31oC, 70% relative humidity. During the trials, rectal temperature (Trec, ratings of perceived exertion (RPE and oxygen uptake (VO2 were recorded. Blood samples were collected for the determination of plasma volume changes (PVC, malondialdehyde (MDA, creatine kinase (CK, total antioxidant status (TAS and vitamin E. After the supplementation regimen, serum alpha-tocopherol increased ~33% but serum concentrations of tocotrienols were negligible. No significant differences were evident in mean Trec, RPE, VO2 or in the time to exhaustion between the E-supplemented and the placebo- supplemented groups. Similarly, mean PVC, CK and TAS were also not different between the two groups. Resting plasma mean MDA concentration in the E-supplemented group was significantly lower than that in the placebo-supplemented group. At exhaustion, plasma mean MDA was higher than the resting values in both groups. Although tocotrienol-rich palm vitamin E supplementation decreased lipid peroxidation at rest and, to some extent, during exercise in the heat, as evident from the lower MDA levels, it however did not enhance endurance running performance or prevent exercise-induced muscle damage or influenced body core temperature or plasma volume changes during exercise in the heat

Dehydration: physiology, assessment, and performance effects.

Science.gov (United States)

Cheuvront, Samuel N; Kenefick, Robert W

2014-01-01

This article provides a comprehensive review of dehydration assessment and presents a unique evaluation of the dehydration and performance literature. The importance of osmolality and volume are emphasized when discussing the physiology, assessment, and performance effects of dehydration. The underappreciated physiologic distinction between a loss of hypo-osmotic body water (intracellular dehydration) and an iso-osmotic loss of body water (extracellular dehydration) is presented and argued as the single most essential aspect of dehydration assessment. The importance of diagnostic and biological variation analyses to dehydration assessment methods is reviewed and their use in gauging the true potential of any dehydration assessment method highlighted. The necessity for establishing proper baselines is discussed, as is the magnitude of dehydration required to elicit reliable and detectable osmotic or volume-mediated compensatory physiologic responses. The discussion of physiologic responses further helps inform and explain our analysis of the literature suggesting a ≥ 2% dehydration threshold for impaired endurance exercise performance mediated by volume loss. In contrast, no clear threshold or plausible mechanism(s) support the marginal, but potentially important, impairment in strength, and power observed with dehydration. Similarly, the potential for dehydration to impair cognition appears small and related primarily to distraction or discomfort. The impact of dehydration on any particular sport skill or task is therefore likely dependent upon the makeup of the task itself (e.g., endurance, strength, cognitive, and motor skill). © 2014 American Physiological Society.

Effects of Acute Endurance Exercise Performed in the Morning and Evening on Inflammatory Cytokine and Metabolic Hormone Responses.

Directory of Open Access Journals (Sweden)

Hyeon-Ki Kim

Full Text Available To compare the effects of endurance exercise performed in the morning and evening on inflammatory cytokine responses in young men.Fourteen healthy male participants aged 24.3 ± 0.8 years (mean ± standard error performed endurance exercise in the morning (0900-1000 h on one day and then in the evening (1700-1800 h on another day with an interval of at least 1 week between each trial. In both the morning and evening trials, the participants walked for 60 minutes at approximately 60% of the maximal oxygen uptake (VO2max on a treadmill. Blood samples were collected to determine hormones and inflammatory cytokines at pre-exercise, immediately post exercise, and 2 h post exercise.Plasma interleukin (IL-6 and adrenaline concentrations were significantly higher immediately after exercise in the evening trial than in the morning trial (P < 0.01, both. Serum free fatty acids concentrations were significantly higher in the evening trial than in the morning trial at 2 h after exercise (P < 0.05. Furthermore, a significant correlation was observed between the levels of IL-6 immediately post-exercise and free fatty acids 2 h post-exercise in the evening (r = 0.68, P < 0.01.These findings suggest that the effect of acute endurance exercise in the evening enhances the plasma IL-6 and adrenaline concentrations compared to that in the morning. In addition, IL-6 was involved in increasing free fatty acids, suggesting that the evening is more effective for exercise-induced lipolysis compared with the morning.

Mouth rinsing improves cycling endurance performance during Ramadan fasting in a hot humid environment.

Science.gov (United States)

Che Muhamed, Ahmad Munir; Mohamed, Nazirah Gulam; Ismail, Norjana; Aziz, Abdul Rashid; Singh, Rabindarjeet

2014-04-01

This study examined the effect of mouth rinsing during endurance cycling in a hot humid environment (32 °C and 75% relative humidity) on athletes in the Ramadan fasted state. Nine trained adolescent male cyclists completed 3 trials that consisted of a carbohydrate mouth-rinse (CMR), a placebo mouth-rinse (PMR), and a no-rinse (NOR) trial during the last 2 weeks of Ramadan. Each trial consisted of a preloading cycle at 65% peak rate of oxygen consumption for 30 min followed by a 10-km time trial (TT10 km) under hot humid condition. During the CMR and PMR trials, each cyclist rinsed his mouth with 25 mL of the solution for 5 s before expectorating the solution pre-exercise, after 5, 15, and 25 min of the preloading cycle, and 15 s prior to the start of TT10 km. Time to complete the TT10 km was significantly faster in the CMR and PMR trials compared with the NOR trial (12.9 ± 1.7 and 12.6 ± 1.7 vs. 16.8 ± 1.6 min, respectively; p benefits compared with a no-rinse condition on TT10 km performance in acute Ramadan fasted subjects during endurance cycling in a heat stress environment.

Exercise training reveals trade-offs between endurance performance and immune function, but does not influence growth, in juvenile lizards.

Science.gov (United States)

Husak, Jerry F; Roy, Jordan C; Lovern, Matthew B

2017-04-15

Acquired energetic resources allocated to a particular trait cannot then be re-allocated to a different trait. This often results in a trade-off between survival and reproduction for the adults of many species, but such a trade-off may be manifested differently in juveniles not yet capable of reproduction. Whereas adults may allocate resources to current and/or future reproduction, juveniles can only allocate to future reproduction. Thus, juveniles should allocate resources toward traits that increase survival and their chances of future reproductive success. We manipulated allocation of resources to performance, via endurance exercise training, to examine trade-offs among endurance capacity, immune function and growth in juvenile green anole lizards. We trained male and female captive anoles on a treadmill for 8 weeks, with increasing intensity, and compared traits with those of untrained individuals. Our results show that training enhanced endurance capacity equally in both sexes, but immune function was suppressed only in females. Training had no effect on growth, but males had higher growth rates than females. Previous work showed that trained adults have enhanced growth, so juvenile growth is either insensitive to stimulation with exercise, or they are already growing at maximal rates. Our results add to a growing body of literature indicating that locomotor performance is an important part of life-history trade-offs that are sex and age specific. © 2017. Published by The Company of Biologists Ltd.

No Evidence of a Common DNA Variant Profile Specific to World Class Endurance Athletes

Science.gov (United States)

Wolfarth, Bernd; Wang, Guan; Sarzynski, Mark A.; Alexeev, Dmitry G.; Ahmetov, Ildus I.; Boulay, Marcel R.; Cieszczyk, Pawel; Eynon, Nir; Filipenko, Maxim L.; Garton, Fleur C.; Generozov, Edward V.; Govorun, Vadim M.; Houweling, Peter J.; Kawahara, Takashi; Kostryukova, Elena S.; Kulemin, Nickolay A.; Larin, Andrey K.; Maciejewska-Karłowska, Agnieszka; Miyachi, Motohiko; Muniesa, Carlos A.; Murakami, Haruka; Ospanova, Elena A.; Padmanabhan, Sandosh; Pavlenko, Alexander V.; Pyankova, Olga N.; Santiago, Catalina; Sawczuk, Marek; Scott, Robert A.; Uyba, Vladimir V.; Yvert, Thomas; Perusse, Louis; Ghosh, Sujoy; Rauramaa, Rainer; North, Kathryn N.; Lucia, Alejandro; Pitsiladis, Yannis; Bouchard, Claude

2016-01-01

There are strong genetic components to cardiorespiratory fitness and its response to exercise training. It would be useful to understand the differences in the genomic profile of highly trained endurance athletes of world class caliber and sedentary controls. An international consortium (GAMES) was established in order to compare elite endurance athletes and ethnicity-matched controls in a case-control study design. Genome-wide association studies were undertaken on two cohorts of elite endurance athletes and controls (GENATHLETE and Japanese endurance runners), from which a panel of 45 promising markers was identified. These markers were tested for replication in seven additional cohorts of endurance athletes and controls: from Australia, Ethiopia, Japan, Kenya, Poland, Russia and Spain. The study is based on a total of 1520 endurance athletes (835 who took part in endurance events in World Championships and/or Olympic Games) and 2760 controls. We hypothesized that world-class athletes are likely to be characterized by an even higher concentration of endurance performance alleles and we performed separate analyses on this subsample. The meta-analysis of all available studies revealed one statistically significant marker (rs558129 at GALNTL6 locus, p = 0.0002), even after correcting for multiple testing. As shown by the low heterogeneity index (I2 = 0), all eight cohorts showed the same direction of association with rs558129, even though p-values varied across the individual studies. In summary, this study did not identify a panel of genomic variants common to these elite endurance athlete groups. Since GAMES was underpowered to identify alleles with small effect sizes, some of the suggestive leads identified should be explored in expanded comparisons of world-class endurance athletes and sedentary controls and in tightly controlled exercise training studies. Such studies have the potential to illuminate the biology not only of world class endurance performance but

No Evidence of a Common DNA Variant Profile Specific to World Class Endurance Athletes.

Directory of Open Access Journals (Sweden)

Tuomo Rankinen

Full Text Available There are strong genetic components to cardiorespiratory fitness and its response to exercise training. It would be useful to understand the differences in the genomic profile of highly trained endurance athletes of world class caliber and sedentary controls. An international consortium (GAMES was established in order to compare elite endurance athletes and ethnicity-matched controls in a case-control study design. Genome-wide association studies were undertaken on two cohorts of elite endurance athletes and controls (GENATHLETE and Japanese endurance runners, from which a panel of 45 promising markers was identified. These markers were tested for replication in seven additional cohorts of endurance athletes and controls: from Australia, Ethiopia, Japan, Kenya, Poland, Russia and Spain. The study is based on a total of 1520 endurance athletes (835 who took part in endurance events in World Championships and/or Olympic Games and 2760 controls. We hypothesized that world-class athletes are likely to be characterized by an even higher concentration of endurance performance alleles and we performed separate analyses on this subsample. The meta-analysis of all available studies revealed one statistically significant marker (rs558129 at GALNTL6 locus, p = 0.0002, even after correcting for multiple testing. As shown by the low heterogeneity index (I2 = 0, all eight cohorts showed the same direction of association with rs558129, even though p-values varied across the individual studies. In summary, this study did not identify a panel of genomic variants common to these elite endurance athlete groups. Since GAMES was underpowered to identify alleles with small effect sizes, some of the suggestive leads identified should be explored in expanded comparisons of world-class endurance athletes and sedentary controls and in tightly controlled exercise training studies. Such studies have the potential to illuminate the biology not only of world class endurance

Muscle morphology of the vastus lateralis is strongly related to ergometer performance, sprint capacity and endurance capacity in Olympic rowers

NARCIS (Netherlands)

van der Zwaard, Stephan; Weide, Guido; Levels, Koen; Eikelboom, Michelle R.I.; Noordhof, Dionne A.; Hofmijster, Mathijs J.; van der Laarse, Willem J.; de Koning, Jos J.; de Ruiter, Cornelis J.; Jaspers, Richard T.

2018-01-01

Rowers need to combine high sprint and endurance capacities. Muscle morphology largely explains muscle power generating capacity, however, little is known on how muscle morphology relates to rowing performance measures. The aim was to determine how muscle morphology of the vastus lateralis relates

Endurance Training - Science and Practice

African Journals Online (AJOL)

I have always had an interest in endurance sports and have been fortunate enough to work with endurance athletes while completing my PhD. Professor Mujika is a well-respected scientist who, apart from his research work, consults with many elite endurance athletes. I was surprised at how excited I was to review.

Glucose ingestion during endurance training does not alter adaptation

DEFF Research Database (Denmark)

Åkerström, Thorbjörn; Fischer, Christian P; Plomgaard, Peter

2009-01-01

, 2) lower citrate synthase (CS) and beta-hydroxyacyl-CoA dehydrogenase (beta-HAD) activity and glycogen content in skeletal muscle, and 3) attenuated endurance performance enhancement in the trained state. To investigate this we studied nine male subjects who performed 10 wk of one-legged knee...... extensor training. They trained one leg while ingesting a 6% glucose solution (Glc) and ingested a sweetened placebo while training the other leg (Plc). The subjects trained their respective legs 2 h at a time on alternate days 5 days a week. Endurance training increased peak power (P(max)) and time...

Relationships between trunk performance, gait and postural control in persons with multiple sclerosis.

Science.gov (United States)

Freund, Jane E; Stetts, Deborah M; Vallabhajosula, Srikant

2016-06-30

Multiple sclerosis (MS) is a chronic progressive disease of the central nervous system. Compared to healthy individuals, persons with multiple sclerosis (PwMS) have increased postural sway in quiet stance, decreased gait speed and increased fall incidence. Trunk performance has been implicated in postural control, gait dysfunction, and fall prevention in older adults. However, the relationship of trunk performance to postural control and gait has not been adequately studied in PwMS. To compare trunk muscle structure and performance in PwMS to healthy age and gendered-matched controls (HC); to determine the effects of isometric trunk endurance testing on postural control in both populations; and to determine the relationship of trunk performance with postural control, gait and step activity in PwMS. Fifteen PwMS and HC completed ultrasound imaging of trunk muscles, 10 m walk test, isometric trunk endurance tests, and postural sway test. Participants wore a step activity monitor for 7 days. PwMS had worse isometric trunk endurance compared to HC. PwMS trunk flexion endurance negatively correlated to several postural control measures and positively correlated to gait speed and step activity. Clinicians should consider evaluation and interventions directed at impaired trunk endurance in PwMS.

Conference on "Multidisciplinary approaches to nutritional problems". Symposium on "Performance, exercise and health". Hydration, fluids and performance.

Science.gov (United States)

Shirreffs, Susan M

2009-02-01

Sweat evaporation can be a key thermoregulatory mechanism and it causes a loss of water from all compartments of the body. Hypohydration can also develop with restricted fluid intake or with intake of diuretics. Hypohydration can affect physical and/or mental performance and/or have implications for dietary recommendations. A variety of different types and modes of exercise performance can be influenced by hydration state. Reviews of the published literature are currently most conclusive for endurance exercise. Dehydration equivalent to 2% body mass loss during exercise in a hot environment (31-32 degrees C) impairs endurance performance, but when the exercise is performed in a temperate environment (20-21 degrees C) a 2% body mass loss appears to have a lesser and inconsequential effect. In cold environments a body mass loss >2% may be tolerable for endurance exercise. There is a less conclusive picture as to the effects of hypohydration on other types of physical performance, including strength and power activities, team sports and the skills component of many sports, and for mental performance. A number of physiological mechanisms are responsible for the effects observed. Fluid consumption can be used to attenuate the development of a water deficit or to correct it. The composition and temperature of a drink and the volume and rate of its consumption can all influence the physiological responses to ingestion and can impact on exercise performance.

Endurance time method for Seismic analysis and design of structures

International Nuclear Information System (INIS)

Estekanchi, H.E.; Vafai, A.; Sadeghazar, M.

2004-01-01

In this paper, a new method for performance based earthquake analysis and design has been introduced. In this method, the structure is subjected to accelerograms that impose increasing dynamic demand on the structure with time. Specified damage indexes are monitored up to the collapse level or other performance limit that defines the endurance limit point for the structure. Also, a method for generating standard intensifying accelerograms has been described. Three accelerograms have been generated using this method. Furthermore, the concept of Endurance Time has been described by applying these accelerograms to single and multi degree of freedom linear systems. The application of this method for analysis of complex nonlinear systems has been explained. Endurance Time method provides a uniform approach to seismic analysis and design of complex structures that can be applied in numerical and experimental investigations

Development of bacoside enriched date syrup juice and its evaluation for physical endurance.

Science.gov (United States)

Anand, T; Prakash, K Bhanu; Pandareesh, M D; Khanum, Farhath

2014-12-01

Bacoside rich juice (BRJ) was developed using date syrup as base. BRJ was evaluated for physicochemical, sensory attributes and its effect on physical endurance. Overall acceptability of BRJ and date syrup juice (DSJ) was good according to hedonic scale/ratings. Twenty four adult male Wistar rats were divided into 4 groups (n = 6). Sedentary (Group I) and control (Group II) group rats were allowed to drink water whereas DSJ and BRJ group rats were provided free access to drink DSJ (Group III) and BRJ (Group IV) for 14 days and were subjected to weight-loaded forced swim test (WFST) for every alternate day in order to evaluate the physical endurance. Both BRJ and DSJ group rats swimming efficiency was improved by 3 and 2 folds respectively in comparison with control group on day- 15. Improved physical endurance in BRJ group is due to reduced malondialdehyde levels in brain, liver and muscle tissues by 16.50 %, 17.88 % and 30.20 %, respectively, compared to DSJ group (p < 0.01). In addition, administration of BRJ significantly protected the hepatic and muscle glycogen levels and reduced the levels of lactic acid in comparison to DSJ group. Hence, the present study clearly indicates that BRJ is an effective anti-fatigue drink ameliorates the various impairments associated with physical endurance.

ALCOHOL AND DISTRACTION INTERACT TO IMPAIR DRIVING PERFORMANCE

Science.gov (United States)

Harrison, Emily L. R.; Fillmore, Mark T.

2011-01-01

Background Recognition of the risks associated with alcohol intoxication and driver distraction has led to a wealth of simulated driving research aimed at studying the adverse effects of each of these factors. Research on driving has moved beyond the individual, separate examination of these factors to the examination of potential interactions between alcohol intoxication and driver distraction. In many driving situations, distractions are commonplace and might have little or no disruptive influence on primary driving functions. Yet, such distractions might become disruptive to a driver who is intoxicated. Methods The present study examined the interactive impairing effects of alcohol intoxication and driver distraction on simulated driving performance in 40 young adult drivers using a divided attention task as a distracter activity. The interactive influence of alcohol and distraction was tested by having drivers perform the driving task under four different conditions: 0.65 g/kg alcohol; 0.65 g/kg alcohol + divided attention; placebo; and placebo + divided attention. Results As hypothesized, divided attention had no impairing effect on driving performance in sober drivers. However, under alcohol, divided attention exacerbated the impairing effects of alcohol on driving precision. Conclusions Alcohol and distraction continue to be appropriate targets for research into ways to reduce the rates of driving-related fatalities and injuries. Greater consideration of how alcohol and distraction interact to impair aspects of driving performance can further efforts to create prevention and intervention measures to protect drivers, particularly young adults. PMID:21277119

Alcohol and distraction interact to impair driving performance.

Science.gov (United States)

Harrison, Emily L R; Fillmore, Mark T

2011-08-01

Recognition of the risks associated with alcohol intoxication and driver distraction has led to a wealth of simulated driving research aimed at studying the adverse effects of each of these factors. Research on driving has moved beyond the individual, separate examination of these factors to the examination of potential interactions between alcohol intoxication and driver distraction. In many driving situations, distractions are commonplace and might have little or no disruptive influence on primary driving functions. Yet, such distractions might become disruptive to a driver who is intoxicated. The present study examined the interactive impairing effects of alcohol intoxication and driver distraction on simulated driving performance in 40 young adult drivers using a divided attention task as a distracter activity. The interactive influence of alcohol and distraction was tested by having drivers perform the driving task under four different conditions: 0.65 g/kg alcohol; 0.65 g/kg alcohol+divided attention; placebo; and placebo+divided attention. As hypothesized, divided attention had no impairing effect on driving performance in sober drivers. However, under alcohol, divided attention exacerbated the impairing effects of alcohol on driving precision. Alcohol and distraction continue to be appropriate targets for research into ways to reduce the rates of driving-related fatalities and injuries. Greater consideration of how alcohol and distraction interact to impair aspects of driving performance can further efforts to create prevention and intervention measures to protect drivers, particularly young adults. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Metabolic clues regarding the enhanced performance of elite endurance athletes from orchiectomy-induced hormonal changes.

Science.gov (United States)

Atwood, Craig S; Bowen, Richard L

2007-01-01

This article examines the metabolic performance of an elite cyclist, Lance Armstrong, before and after his diagnosis with testicular cancer. Although a champion cyclist in 1-day events prior to his diagnosis of testicular cancer at age 25, he was not a contender in multi-day endurance cycle races such as the 3-week Tour de France. His genetic makeup and physiology (high VO2max, long femur, strong heavy build) coupled with his ambition and motivation enabled him at an early age to become one of the best 1-day cyclists in the world. Following his cancer diagnosis, he underwent a unilateral orchiectomy, brain surgery and four cycles of chemotherapy. After recovering, he returned to cycling and surprisingly excelled in the Tour de France, winning this hardest of endurance events 7 years running. This dramatic transformation from a 1-day to a 3-week endurance champion has led many to query how this is possible, and under the current climate, has led to suggestions of doping as to the answer to this metamorphosis. Physiological tests following his recovery indicated that physiological parameters such as VO2max were not affected by the unilateral orchiectomy and chemotherapy. We propose that his dramatic improvement in recovery between stages, the most important factor in winning multi-day stage races, is due to his unilateral orchiectomy, a procedure that results in permanent changes in serum hormones. These hormonal changes, specifically an increase in gonadotropins (and prolactin) required to maintain serum testosterone levels, alter fuel metabolism; increasing hormone sensitive lipase expression and activity, promoting increased free fatty acid (FFA) mobilization to, and utilization by, muscles, thereby decreasing the requirement to expend limiting glycogen stores before, during and after exercise. Such hormonal changes also have been associated with ketone body production, improvements in muscle repair and haematocrit levels and may facilitate the loss of body weight

Effect of Conjugated Linoleic Acid Intake on Endurance Exercise Performance and Anti-fatigue in Student Athletes.

Science.gov (United States)

Terasawa, Naoko; Okamoto, Ken; Nakada, Kenta; Masuda, Kazumi

2017-07-01

Conjugated linoleic acids (CLA) intake has been reported to reduce body fat mass or increase lean body mass and to improve exercise outcome by modulating testosterone in humans. These reports have studied mostly overweight subjects; few were athletes. Therefore, in this study, the effect of CLA intake on endurance performance and anti-fatigue in student athletes was investigated. A double-blind, crossover study was conducted with 10 male student athletes. Each subject was administered with either CLA (net 0.9 g/day) or a placebo for 14 days. They were subjected to an exercise tolerance test (steady loading) using a cycle ergometer on days 0 and 14. Peak VO 2 was determined for each subject using a graded loading test. The steady loading test was performed with a pedaling exercise load of 50% peak VO 2 for 40 min and then with a load of 70% peak VO 2 until exhaustion. Blood sampling and measurement of critical flicker frequency (CFF) were performed before and after exercise. The rate of perceived exertion (RPE) was measured serially during exercise. In the results, amount of body weight variation significantly increased and amount of body fat percentage variation tended to decrease by CLA intake, it might have an effect by increase in muscle mass. In addition, amount of exercise time variation significantly increased, amount of variation of CFF before and after exercise tended to increase, that of RPE during exercise tended to decrease, and that of creatine phosphokinase before and after exercise tended to decrease in the CLA group. These results suggested that CLA intake for 14 days might have an effect on endurance performance and anti-fatigue in student athletes.

Beta-blockers do not impair the cardiovascular benefits of endurance training in hypertensives.

Science.gov (United States)

Westhoff, T H; Franke, N; Schmidt, S; Vallbracht-Israng, K; Zidek, W; Dimeo, F; van der Giet, M

2007-06-01

Aerobic physical exercise is broadly recommended as a helpful adjunct to obtain blood pressure control in hypertension. Beta-blockade interacts with heart rate, sympathetic tone, maximal workload and local lactate production. In the present randomized-controlled study, we compared the cardiovascular effects of an endurance training programme in elderly hypertensives with or without beta-blockers and developed a first approach to determine a lactate-based training heart rate in presence of beta-blockade. Fifty-two patients (23 with beta-blocker, 29 without beta-blocker) > or =60 years with systolic 24-h ambulatory blood pressure (ABP) > or =140 mm Hg and/or antihypertensive treatment were randomly assigned to sedentary activity or a heart-rate controlled 12-week treadmill exercise programme (lactate 2.0 mmol/l). In the exercise group, the training significantly decreased systolic and diastolic 24-h ABP, blood pressure on exertion (100 W) and increased endothelium-dependent vasodilation (flow-mediated vasodilation, FMD) and physical performance both in the presence and absence of beta-blockade (Pendurance training evokes comparable cardiovascular benefits in the presence and absence of beta-blockade including a marked improvement of endothelial function. In the present study, target training heart rate with beta-blockers is about 18% lower than without.

Seasonal Variation of Agility, Speed and Endurance Performance in Young Elite Soccer Players

Directory of Open Access Journals (Sweden)

Michal Dragijsky

2017-02-01

Full Text Available The aim of this study was to investigate changes in the linear running speed (LRS for 30 m, change of direction speed (CODS, and endurance in young elite Czech soccer players. The following tests were conducted to assess CODS and endurance: Agility 505 turning toward the dominant (A505DL and non-dominant lower limb (A505NL; Illinois Agility Test (IAT; and intermittent test (Yo-Yo IRT1. During the soccer season, we investigated performance at the following time periods: the start (t1 and the end of the pre-season period (t2; during (t3 and at the end of the competitive period (t4. Repeated measurement analysis of variance revealed a significant effect of time period on selected fitness parameters (p < 0.05. Post hoc analysis for test A505DL revealed significant improvements of performance at t3 (2.71 ± 0.08 s and t4 (2.72 ± 0.06 s compared to t1 (2.81 ± 0.09 s. A505NL was significantly different between t1 (2.83 ± 0.09 s and t2 (2.76 ± 0.09 s, t3 (2.7 ± 0.07 s and t4 (2.71 ± 0.09 s. Performance of CODS at t1 for the IAT (18.82 ± 0.56 s was significantly lower (p < 0.05 than any other time period (t2 = 18.52 ± 0.63 s, t3 = 17.94 ± 0.51 s, t4 = 17.89 ± 0.66 s. The power of LRS was significantly different at t3 (4.99 ± 0.15 s, and t4 (4.98 ± 0.17 s compared to t1 (5.15 ± 0.21 s, and t2 (5.07 ± 0.14 s. For the Yo-Yo IRT1 test, we observed a significant increase in performance between t1 (625.26 ± 170.34 m, t2 (858.95 ± 210.55 m, and t3 (953.68 ± 229.88 m. These results show the impact of soccer season time period on young soccer player performance and may further serve as a basis for comparison with similar research conducted by peers. These results may aid sports practice for clinicians, conditioning coaches, soccer coaches and physiotherapeutic coaches.

Effects of order and sequence of resistance and endurance training on body fat in elementary school-aged girls

Directory of Open Access Journals (Sweden)

Ana R. Alves

2017-12-01

Full Text Available The purpose of this study was to analyse the effects of order and sequence of concurrent resistance and endurance training on body fat percentage (BFP in a large sample of elementary school-aged girls. One hundred and twenty-six healthy girls, aged 10-11 years (10.95 ± 0.48 years, were randomly assigned to six groups to perform different training protocols per week for 8 weeks: Resistance-only (R, Endurance-only (E, Concurrent Distinct Endurance-Resistance (CDER, Concurrent Parallel Endurance-Resistance (CPER, Concurrent Parallel Resistance-Endurance (CPRE, and a Control group (C. In R and E, the subjects performed single sessions of resistance or endurance exercises, respectively (two days per week. In CDER, resistance-endurance training was performed on different days each week (four days per week. CPER and CPRE performed single-session combined endurance-resistance training or combined resistance-endurance training, respectively, each week (two days per week. After an 8-week training period, BFP decreased in all experimental groups (CPER: 13.3%, p0.05; and CDER: 5.6%, p>0.05. However, a significant difference was found in CPER and CPRE when compared to CDER, E, and R, indicating that training sequence may influence BFP. All programmes were effective, but CPER and CPRE obtained better results for BFP than CDER, E, or R. The effects of concurrent resistance and endurance training on body fat percentage can be mediated by order and sequence of exercise. These results provide insight into optimization of school-based fat loss exercise programmes in childhood.

Comparability and repeatability of three commonly used methods for measuring endurance capacity.

Science.gov (United States)

Baxter-Gilbert, James; Mühlenhaupt, Max; Whiting, Martin J

2017-12-01

Measures of endurance (time to exhaustion) have been used to address a wide range of questions in ecomorphological and physiological research, as well as being used as a proxy for survival and fitness. Swimming, stationary (circular) track running, and treadmill running are all commonly used methods for measuring endurance. Despite the use of these methods across a broad range of taxa, how comparable these methods are to one another, and whether they are biologically relevant, is rarely examined. We used Australian water dragons (Intellagama lesueurii), a species that is morphologically adept at climbing, swimming, and running, to compare these three methods of endurance and examined if there is repeatability within and between trial methods. We found that time to exhaustion was not highly repeatable within a method, suggesting that single measures or a mean time to exhaustion across trials are not appropriate. Furthermore, we compared mean maximal endurance times among the three methods, and found that the two running methods (i.e., stationary track and treadmill) were similar, but swimming was distinctly different, resulting in lower mean maximal endurance times. Finally, an individual's endurance rank was not repeatable across methods, suggesting that the three endurance trial methods are not providing similar information about an individual's performance capacity. Overall, these results highlight the need to carefully match a measure of performance capacity with the study species and the research questions being asked so that the methods being used are behaviorally, ecologically, and physiologically relevant. © 2018 Wiley Periodicals, Inc.

Nutritional Ketosis Alters Fuel Preference and Thereby Endurance Performance in Athletes.

Science.gov (United States)

Cox, Pete J; Kirk, Tom; Ashmore, Tom; Willerton, Kristof; Evans, Rhys; Smith, Alan; Murray, Andrew J; Stubbs, Brianna; West, James; McLure, Stewart W; King, M Todd; Dodd, Michael S; Holloway, Cameron; Neubauer, Stefan; Drawer, Scott; Veech, Richard L; Griffin, Julian L; Clarke, Kieran

2016-08-09

Ketosis, the metabolic response to energy crisis, is a mechanism to sustain life by altering oxidative fuel selection. Often overlooked for its metabolic potential, ketosis is poorly understood outside of starvation or diabetic crisis. Thus, we studied the biochemical advantages of ketosis in humans using a ketone ester-based form of nutrition without the unwanted milieu of endogenous ketone body production by caloric or carbohydrate restriction. In five separate studies of 39 high-performance athletes, we show how this unique metabolic state improves physical endurance by altering fuel competition for oxidative respiration. Ketosis decreased muscle glycolysis and plasma lactate concentrations, while providing an alternative substrate for oxidative phosphorylation. Ketosis increased intramuscular triacylglycerol oxidation during exercise, even in the presence of normal muscle glycogen, co-ingested carbohydrate and elevated insulin. These findings may hold clues to greater human potential and a better understanding of fuel metabolism in health and disease. Copyright © 2016 Elsevier Inc. All rights reserved.

Transient impairments in single muscle fibre contractile function after prolonged cycling in elite endurance athletes

DEFF Research Database (Denmark)

Hvid, L G; Gejl, Kasper Degn; Bech, R D

2013-01-01

Prolonged muscle activity impairs whole-muscle performance and function. However, little is known about the effects of prolonged muscle activity on the contractile function of human single muscle fibres. The purpose of this study was to investigate the effects of prolonged exercise and subsequent...... recovery on the contractile function of single muscle fibres obtained from elite athletes....

Postexercise Dietary Protein Strategies to Maximize Skeletal Muscle Repair and Remodeling in Masters Endurance Athletes: A Review.

Science.gov (United States)

Doering, Thomas M; Reaburn, Peter R; Phillips, Stuart M; Jenkins, David G

2016-04-01

Participation rates of masters athletes in endurance events such as long-distance triathlon and running continue to increase. Given the physical and metabolic demands of endurance training, recovery practices influence the quality of successive training sessions and, consequently, adaptations to training. Research has suggested that, after muscle-damaging endurance exercise, masters athletes experience slower recovery rates in comparison with younger, similarly trained athletes. Given that these discrepancies in recovery rates are not observed after non-muscle-damaging exercise, it is suggested that masters athletes have impairments of the protein remodeling mechanisms within skeletal muscle. The importance of postexercise protein feeding for endurance athletes is increasingly being acknowledged, and its role in creating a positive net muscle protein balance postexercise is well known. The potential benefits of postexercise protein feeding include elevating muscle protein synthesis and satellite cell activity for muscle repair and remodeling, as well as facilitating muscle glycogen resynthesis. Despite extensive investigation into age-related anabolic resistance in sedentary aging populations, little is known about how anabolic resistance affects postexercise muscle protein synthesis and thus muscle remodeling in aging athletes. Despite evidence suggesting that physical training can attenuate but not eliminate age-related anabolic resistance, masters athletes are currently recommended to consume the same postexercise dietary protein dose (approximately 20 g or 0.25 g/kg/meal) as younger athletes. Given the slower recovery rates of masters athletes after muscle-damaging exercise, which may be due to impaired muscle remodeling mechanisms, masters athletes may benefit from higher doses of postexercise dietary protein, with particular attention directed to the leucine content of the postexercise bolus.

Endurance training increases the efficiency of rat skeletal muscle mitochondria.

Science.gov (United States)

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

2016-10-01

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

Venous hemogasometry of equines finalists in 90 km endurance races

Directory of Open Access Journals (Sweden)

Cinthia B.S. Dumont

2014-06-01

Full Text Available Front of exercise, the organic systems may suffer water-electrolyte and acid-base imbalances, particularly in the case of blood gases, demonstrating variations from different causes, whether respiratory and/or metabolic. Understanding the physiological adaptations to exercise is essential in the search for the optimum performance. In this way, this study measured the venous blood gases (pO2, pCO2, as well as the oxygen saturation (SatO2 in healthy equines, Arabian horses finalists in 90km endurance races. A total of fourteen Arabian horses were evaluated, nine males and five females, between six and 12 years old, finalists in 90km endurance races. There was a significant reduction in pO2, pCO2 and SatO2 after the exercise, however, the values remained within the normality range, and did not change the athletic performance of the animals, indicating a temporary alteration, assuming thus a character of physiological response to the exercise performed. The equines, finalists in 90 Km endurance races, demonstrated efficient ventilatory process, without any alterations in the athletic performance, being adapted to the type of exercise imposed.

Effects of Beetroot Juice Supplementation on Cardiorespiratory Endurance in Athletes. A Systematic Review

Directory of Open Access Journals (Sweden)

Raúl Domínguez

2017-01-01

Full Text Available Athletes use nutritional supplementation to enhance the effects of training and achieve improvements in their athletic performance. Beetroot juice increases levels of nitric oxide (NO, which serves multiple functions related to increased blood flow, gas exchange, mitochondrial biogenesis and efficiency, and strengthening of muscle contraction. These biomarker improvements indicate that supplementation with beetroot juice could have ergogenic effects on cardiorespiratory endurance that would benefit athletic performance. The aim of this literature review was to determine the effects of beetroot juice supplementation and the combination of beetroot juice with other supplements on cardiorespiratory endurance in athletes. A keyword search of DialNet, MedLine, PubMed, Scopus and Web of Science databases covered publications from 2010 to 2016. After excluding reviews/meta-analyses, animal studies, inaccessible full-text, and studies that did not supplement with beetroot juice and adequately assess cardiorespiratory endurance, 23 articles were selected for analysis. The available results suggest that supplementation with beetroot juice can improve cardiorespiratory endurance in athletes by increasing efficiency, which improves performance at various distances, increases time to exhaustion at submaximal intensities, and may improve the cardiorespiratory performance at anaerobic threshold intensities and maximum oxygen uptake (VO2max. Although the literature shows contradictory data, the findings of other studies lead us to hypothesize that supplementing with beetroot juice could mitigate the ergolytic effects of hypoxia on cardiorespiratory endurance in athletes. It cannot be stated that the combination of beetroot juice with other supplements has a positive or negative effect on cardiorespiratory endurance, but it is possible that the effects of supplementation with beetroot juice can be undermined by interaction with other supplements such as caffeine.

Autonomous Soaring for Improved Endurance of a Small Uninhabited Air Vehicle

Science.gov (United States)

Allen, Michael J.

2005-01-01

A relatively unexplored method to improve the endurance of an autonomous aircraft is to use buoyant plumes of air found in the lower atmosphere called thermals or updrafts. Glider pilots and birds commonly use updrafts to improve range, endurance, or cross-country speed. This report presents a quantitative analysis of a small electric-powered uninhabited air vehicle using updrafts to extend its endurance over a target location. A three-degree-of-freedom simulation of the uninhabited air vehicle was used to determine the yearly effect of updrafts on performance. Surface radiation and rawinsonde balloon measurements taken at Desert Rock, Nevada, were used to determine updraft size, strength, spacing, shape, and maximum height for the simulation. A fixed-width spiral path was used to search for updrafts at the same time as maintaining line-of-sight to the surface target position. Power was used only when the aircraft was flying at the lower-altitude limit in search of updrafts. Results show that an uninhabited air vehicle with a nominal endurance of 2 hours can fly a maximum of 14 hours using updrafts during the summer and a maximum of 8 hours during the winter. The performance benefit and the chance of finding updrafts both depend on what time of day the uninhabited air vehicle is launched. Good endurance and probability of finding updrafts during the year was obtained when the uninhabited air vehicle was launched 30 percent into the daylight hours after sunrise each day. Yearly average endurance was found to be 8.6 hours with these launch times.

RELATIONSHIPS BETWEEN MUSCLE FATIGUE CHARACTERISTICS AND MARKERS OF ENDURANCE PERFORMANCE

Directory of Open Access Journals (Sweden)

Martyn G. Morris

2008-12-01

Full Text Available The aim of this study was to examine the relationship of a range of in-vivo whole muscle characteristics to determinants of endurance performance. Eleven healthy males completed a cycle ergometer step test to exhaustion for the determination of the lactate threshold, gross mechanical efficiency, peak power and VO2max. On two separate occasions, contractile and fatigue characteristics of the quadriceps femoris were collected using a specially designed isometric strength-testing chair. Muscle fatigue was then assessed by stimulating the muscle for 3 minutes. Force, rate of force development and rates of relaxation were calculated at the beginning and end of the 3 minute protocol and examined for reliability and in relation to lactate threshold, VO2max, gross mechanical efficiency and peak power. Muscle characteristics, rate of force development and relaxation rate were demonstrated to be reliable measures. Force drop off over the 3 minutes (fatigue index was related to lactate threshold (r = -0.72 p < 0.01 but not to VO2max. The rate of force development related to the peak power at the end of the cycle ergometer test (r = -0.75 p < 0.01. Rates of relaxation did not relate to any of the performance markers. We found in-vivo whole muscle characteristics, such as the fatigue index and rate of force development, relate to specific markers of peripheral, but not to central, fitness components. Our investigation suggests that muscle characteristics assessed in this way is reliable and could be feasibly utilised to further our understanding of the peripheral factors underpinning performance

Effect of ultra-endurance exercise on left ventricular performance and plasma cytokines in healthy trained men

Directory of Open Access Journals (Sweden)

K Krzemiński

2016-01-01

Full Text Available The purpose of this study was to investigate the effect of ultra-endurance exercise on left ventricular (LV performance and plasma concentration of interleukin (IL-6, IL-10, IL-18 and tumour necrosis factoralpha (TNF-IX as well as to examine the relationships between exercise-induced changes in plasma cytokines and those in echocardiographic indices of LV function in ultra-marathon runners. Nine healthy trained men (mean age 3011.0 years participated in a 100-km ultra-marathon. Heart rate, blood pressure, ejection fraction (EF, fractional shortening (FS, ratio of early (E to late (A mitral inflow peak velocities (E/A, ratio of early (E' to late (A' diastolic mitral annulus peak velocities (E‘/A’ and E-wave deceleration time (DT were obtained by echocardiography before, immediately after and in the 90th minute of the recovery period. Blood samples were taken before each echocardiographic evaluation. The ultra-endurance exercise caused significant increases in plasma IL-6, IL-10, IL-18 and TNF-α. Echocardiography revealed significant decreases in both E and the E/A ratio immediately after exercise, without any significant changes in EF, FS, DT or the E/E’ ratio. At the 90th minute of the recovery period, plasma TNF-or and the E/A ratio did not differ significantly from the pre-exercise values, whereas FS was significantly lower than before and immediately after exercise. The increases in plasma TNF-or correlated with changes in FS (r=0.73 and DT (r=-0.73. It is concluded that ultra-endurance exercise causes alterations in LV diastolic function. The present data suggest that TNF-or might be involved in this effect.

Polarized training has greater impact on key endurance variables than threshold, high intensity or high volume training

Directory of Open Access Journals (Sweden)

Thomas eStöggl

2014-02-01

Full Text Available Endurance athletes integrate four conditioning concepts in their training programs: high-volume training (HVT, ‘threshold-training’ (THR, high-intensity interval training (HIIT and a combination of these aforementioned concepts known as polarized training (POL. The purpose of this study was to explore which of these four training concepts provides the greatest response on key components of endurance performance in well-trained endurance athletes. Methods: Forty eight runners, cyclists, triathletes and cross-country skiers (peak oxygen uptake: (VO2peak: 62.6±7.1 mL∙min-1∙kg-1 were randomly assigned to one of four groups performing over nine weeks. An incremental test, work economy and a VO2peak tests were performed. Training intensity was heart rate controlled. Results: POL demonstrated the greatest increase in VO2peak (+6.8 ml∙min∙kg-1 or 11.7%, P0.05. Conclusion: POL resulted in the greatest improvements in most key variables of endurance performance in well-trained endurance athletes. THR or HVT did not lead to further improvements in performance related variables.

Mental toughness latent profiles in endurance athletes.

Science.gov (United States)

Zeiger, Joanna S; Zeiger, Robert S

2018-01-01

Mental toughness in endurance athletes, while an important factor for success, has been scarcely studied. An online survey was used to examine eight mental toughness factors in endurance athletes. The study aim was to determine mental toughness profiles via latent profile analysis in endurance athletes and whether associations exist between the latent profiles and demographics and sports characteristics. Endurance athletes >18 years of age were recruited via social media outlets (n = 1245, 53% female). Mental toughness was measured using the Sports Mental Toughness Questionnaire (SMTQ), Psychological Performance Inventory-Alternative (PPI-A), and self-esteem was measured using the Rosenberg Self-Esteem Scale (RSE). A three-class solution emerged, designated as high mental toughness (High MT), moderate mental toughness (Moderate MT) and low mental toughness (Low MT). ANOVA tests showed significant differences between all three classes on all 8 factors derived from the SMTQ, PPI-A and the RSE. There was an increased odds of being in the High MT class compared to the Low MT class for males (OR = 1.99; 95% CI, 1.39, 2.83; Pathletes who were over 55 compared to those who were 18-34 (OR = 2.52; 95% CI, 1.37, 4.62; Pathletes. High MT is associated with demographics and sports characteristics. Mental toughness screening in athletes may help direct practitioners with mental skills training.

Mental toughness latent profiles in endurance athletes.

Directory of Open Access Journals (Sweden)

Joanna S Zeiger

Full Text Available Mental toughness in endurance athletes, while an important factor for success, has been scarcely studied. An online survey was used to examine eight mental toughness factors in endurance athletes. The study aim was to determine mental toughness profiles via latent profile analysis in endurance athletes and whether associations exist between the latent profiles and demographics and sports characteristics. Endurance athletes >18 years of age were recruited via social media outlets (n = 1245, 53% female. Mental toughness was measured using the Sports Mental Toughness Questionnaire (SMTQ, Psychological Performance Inventory-Alternative (PPI-A, and self-esteem was measured using the Rosenberg Self-Esteem Scale (RSE. A three-class solution emerged, designated as high mental toughness (High MT, moderate mental toughness (Moderate MT and low mental toughness (Low MT. ANOVA tests showed significant differences between all three classes on all 8 factors derived from the SMTQ, PPI-A and the RSE. There was an increased odds of being in the High MT class compared to the Low MT class for males (OR = 1.99; 95% CI, 1.39, 2.83; P<0.001, athletes who were over 55 compared to those who were 18-34 (OR = 2.52; 95% CI, 1.37, 4.62; P<0.01, high sports satisfaction (OR = 8.17; 95% CI, 5.63, 11.87; P<0.001, and high division placement (OR = 2.18; 95% CI, 1.46,3.26; P<0.001. The data showed that mental toughness latent profiles exist in endurance athletes. High MT is associated with demographics and sports characteristics. Mental toughness screening in athletes may help direct practitioners with mental skills training.

Impairments in site-specific AS160 phosphorylation and effects of exercise training

DEFF Research Database (Denmark)

Consitt, Leslie A; Van Meter, Jessica; Newton, Christopher A

2013-01-01

The purpose of this study was to determine if site-specific phosphorylation at the level of Akt substrate of 160 kDa (AS160) is altered in skeletal muscle from sedentary humans across a wide range of the adult lifespan (18 to 84 years) and if endurance- and/or strength-oriented exercise training ...... population and that exercise training is an effective intervention for treating these impairments.......The purpose of this study was to determine if site-specific phosphorylation at the level of Akt substrate of 160 kDa (AS160) is altered in skeletal muscle from sedentary humans across a wide range of the adult lifespan (18 to 84 years) and if endurance- and/or strength-oriented exercise training...... in whole-body insulin action were associated with impairments in insulin-induced phosphorylation of skeletal muscle AS160 on sites Ser-588, Thr-642, Ser-666 and phospho-Akt substrate (PAS), but not Ser-318 or Ser-751. Twelve weeks of either endurance- or strength-oriented exercise training increased whole...

Energy Monitoring and Control Systems--Performance Verification and Endurance Test Procedures.

Science.gov (United States)

1982-12-01

EM-; tK2 s) trave h.en loadted in qvstem sit ~rp sm:l , o,1 ti-’.~ -1 rouiitthe factoz’, lest. E.VEF.NT Comnmwid the system to display the status of...contractor correction of all outstanding deficiencies . 163 TEST NO: END-i Page I of 1 OBJECTIVE: To demonstrate EMCS normal mode operation 24 TITLE: Endurance

14 CFR 33.49 - Endurance test.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Endurance test. 33.49 Section 33.49... STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.49 Endurance test. (a) General. Each engine must be subjected to an endurance test that includes a total of 150 hours of operation...

Concurrent Development of Endurance Capacity and Explosiveness: Training Characteristics of World-Class Nordic-Combined Athletes.

Science.gov (United States)

Tønnessen, Espen; Rasdal, Vegard; Svendsen, Ida S; Haugen, Thomas A; Hem, Erlend; Sandbakk, Øyvind

2016-07-01

Performing at an elite level in Nordic combined (NC) requires both the explosiveness required for ski jumping performance and the endurance capacity required for cross-country skiing. To describe the characteristics of world-class NC athletes' training and determine how endurance and non-endurance (ie, strength, power, and ski jumping) training is periodized. Annual training characteristics and the periodization of endurance and non-endurance training were determined by analyzing the training diaries of 6 world-class NC athletes. Of 846 ± 72 annual training hours, 540 ± 37 h were endurance training, with 88.6% being low-, 5.9% moderate-, and 5.5% high-intensity training. While training frequency remained relatively constant, the total training volume was reduced from the general preparatory to the competition phase, primarily due to less low- and moderate-intensity training (P ski-jump-specific training (908 ± 165 ski jumps and ski-jump imitations). The proportion of non-endurance training increased significantly toward the competition phase (P ski-jump training. These data provide novel insight on how successful athletes execute their training and may facilitate more-precise coaching of future athletes in this sport. In addition, this information is of high relevance for the training organization of other sports that require optimization of 2 fundamentally different physical capacities.

14 CFR 33.87 - Endurance test.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Endurance test. 33.87 Section 33.87... STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.87 Endurance test. (a) General. Each engine must be subjected to an endurance test that includes a total of at least 150 hours of operation...

14 CFR 35.39 - Endurance test.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Endurance test. 35.39 Section 35.39... STANDARDS: PROPELLERS Tests and Inspections § 35.39 Endurance test. Endurance tests on the propeller system... propellers must be subjected to one of the following tests: (1) A 50-hour flight test in level flight or in...

High-intensity endurance training increases nocturnal heart rate variability in sedentary participants

Directory of Open Access Journals (Sweden)

A Nummela

2016-01-01

Full Text Available The effects of endurance training on endurance performance characteristics and cardiac autonomic modulation during night sleep were investigated during two 4-week training periods. After the first 4-week training period (3 x 40 min per week, at 75% of HRR the subjects were divided into HIGH group (n = 7, who performed three high-intensity endurance training sessions per week; and CONTROL group (n = 8 who did not change their training. An incremental treadmill test was performed before and after the two 4-weektraining periods. Furthermore, nocturnal RR-intervals were recorded after each training day. In the second 4-weektraining period HIGH group increased their V0Zmax (P = 0.005 more than CONTROL group. At the same time, nocturnal HR decreased (P = 0.039 and high-frequency power (HFP increased (P = 0.003 in HIGH group while no changes were observed in CONTROL group. Furthermore, a correlation was observed between the changes in nocturnal HFP and changes in V0Zmax during the second 4-week training period (r = 0.90, P < 0.001. The present study showed that the increased HFP is related to improved VO2max in sedentary subjects suggesting that nocturnal HFP can provide a useful method in monitoring individual responses to endurance training.

Effects of resistance training on endurance capacity and muscle fiber composition in young top-level cyclists

DEFF Research Database (Denmark)

Aagaard, P; Andersen, J L; Bennekou, M

2011-01-01

Equivocal findings exist on the effect of concurrent strength (S) and endurance (E) training on endurance performance and muscle morphology. Further, the influence of concurrent SE training on muscle fiber-type composition, vascularization and endurance capacity remains unknown in top......-level endurance athletes. The present study examined the effect of 16 weeks of concurrent SE training on maximal muscle strength (MVC), contractile rate of force development (RFD), muscle fiber morphology and composition, capillarization, aerobic power (VO(2max) ), cycling economy (CE) and long....../short-term endurance capacity in young elite competitive cyclists (n=14). MVC and RFD increased 12-20% with SE (P...

Effects of resistance training on endurance capacity and muscle fiber composition in young top-level cyclists

DEFF Research Database (Denmark)

Aagaard, P; Andersen, J L; Bennekou, M

2011-01-01

Equivocal findings exist on the effect of concurrent strength (S) and endurance (E) training on endurance performance and muscle morphology. Further, the influence of concurrent SE training on muscle fiber-type composition, vascularization and endurance capacity remains unknown in top......-level endurance athletes. The present study examined the effect of 16 weeks of concurrent SE training on maximal muscle strength (MVC), contractile rate of force development (RFD), muscle fiber morphology and composition, capillarization, aerobic power (VO2max), cycling economy (CE) and long/short-term endurance...... capacity in young elite competitive cyclists (n=14). MVC and RFD increased 12-20% with SE (P...

Thermal endurance tests on silicone rubber specimens

International Nuclear Information System (INIS)

Warburton, C.

1977-07-01

Thermal endurance tests have been performed on a range of silicone rubber specimens at temperature above 300 0 C. It is suggested that the rubber mix A2426, the compound from which Wylfa sealing rings are manufactured, will fail at temperatures above 300 0 C within weeks. Hardness measurements show that this particular rubber performs in a similar manner to Walker's S.I.L./60. (author)

The road to gold: training and peaking characteristics in the year prior to a gold medal endurance performance.

Science.gov (United States)

Tønnessen, Espen; Sylta, Øystein; Haugen, Thomas A; Hem, Erlend; Svendsen, Ida S; Seiler, Stephen

2014-01-01

To describe training variations across the annual cycle in Olympic and World Champion endurance athletes, and determine whether these athletes used tapering strategies in line with recommendations in the literature. Eleven elite XC skiers and biathletes (4 male; 28±1 yr, 85±5 mL x min(-1) x kg(-1) VO2max, 7 female, 25±4 yr, 73±3 mL x min(-1) x kg(-1) VO2max) reported one year of day-to-day training leading up to the most successful competition of their career. Training data were divided into periodization and peaking phases and distributed into training forms, intensity zones and endurance activity forms. Athletes trained ∼800 h/500 sessions x year(-1), including ∼500 h x year(-1) of sport-specific training. Ninety-four percent of all training was executed as aerobic endurance training. Of this, ∼90% was low intensity training (LIT, below the first lactate threshold) and 10% high intensity training (HIT, above the first lactate threshold) by time. Categorically, 23% of training sessions were characterized as HIT with primary portions executed at or above the first lactate turn point. Training volume and specificity distribution conformed to a traditional periodization model, but absolute volume of HIT remained stable across phases. However, HIT training patterns tended to become more polarized in the competition phase. Training volume, frequency and intensity remained unchanged from pre-peaking to peaking period, but there was a 32±15% (Pphase. The annual training data for these Olympic and World champion XC skiers and biathletes conforms to previously reported training patterns of elite endurance athletes. During the competition phase, training became more sport-specific, with 92% performed as XC skiing. However, they did not follow suggested tapering practice derived from short-term experimental studies. Only three out of 11 athletes took a rest day during the final 5 days prior to their most successful competition.

The road to gold: training and peaking characteristics in the year prior to a gold medal endurance performance.

Directory of Open Access Journals (Sweden)

Espen Tønnessen

Full Text Available To describe training variations across the annual cycle in Olympic and World Champion endurance athletes, and determine whether these athletes used tapering strategies in line with recommendations in the literature.Eleven elite XC skiers and biathletes (4 male; 28±1 yr, 85±5 mL x min(-1 x kg(-1 VO2max, 7 female, 25±4 yr, 73±3 mL x min(-1 x kg(-1 VO2max reported one year of day-to-day training leading up to the most successful competition of their career. Training data were divided into periodization and peaking phases and distributed into training forms, intensity zones and endurance activity forms.Athletes trained ∼800 h/500 sessions x year(-1, including ∼500 h x year(-1 of sport-specific training. Ninety-four percent of all training was executed as aerobic endurance training. Of this, ∼90% was low intensity training (LIT, below the first lactate threshold and 10% high intensity training (HIT, above the first lactate threshold by time. Categorically, 23% of training sessions were characterized as HIT with primary portions executed at or above the first lactate turn point. Training volume and specificity distribution conformed to a traditional periodization model, but absolute volume of HIT remained stable across phases. However, HIT training patterns tended to become more polarized in the competition phase. Training volume, frequency and intensity remained unchanged from pre-peaking to peaking period, but there was a 32±15% (P<.01 volume reduction from the preparation period to peaking phase.The annual training data for these Olympic and World champion XC skiers and biathletes conforms to previously reported training patterns of elite endurance athletes. During the competition phase, training became more sport-specific, with 92% performed as XC skiing. However, they did not follow suggested tapering practice derived from short-term experimental studies. Only three out of 11 athletes took a rest day during the final 5 days prior to

The effect of repeated periods of speed endurance training on performance, running economy, and muscle adaptations.

Science.gov (United States)

Skovgaard, C; Almquist, N W; Bangsbo, J

2018-02-01

The effect of repeated intense training interventions was investigated in eight trained male runners (maximum oxygen uptake [VO 2 -max]: 59.3±3.2 mL/kg/min, mean±SD) who performed 10 speed endurance training (SET; repeated 30-seconds "all-out" bouts) and 10 aerobic moderate-intensity training sessions during two 40-day periods (P1 and P2) separated by ~80 days of habitual training. Before and after both P1 and P2, subjects completed an incremental test to exhaustion to determine VO 2 -max and a repeated running test at 90% vVO 2 -max to exhaustion (RRT) to determine short-term endurance capacity. In addition, running economy (RE) was measured at 60% vVO 2 -max (11.9±0.5 km/h) and v10-km (14.3±0.9 km/h), a 10-km track-running test was performed, and a biopsy from m. vastus lateralis was collected. 10-km performance and VO 2 -max (mL/min) were the same prior to P1 and P2, whereas RE was better (P<.05) before P2 than before P1. During P1 and P2, 10-km performance (2.9% and 2.3%), VO 2 -max (2.1% and 2.6%), and RE (1.9% and 1.8% at 60% vVO 2 -max; 1.6% and 2.0% at v10-km) improved (P<.05) to the same extent, respectively. Performance in RRT was 20% better (P<.05) after compared to before P2, with no change in P1. No changes in muscle expression of Na + ,K + -ATPase α1, α2 and β1, NHE1, SERCA1 and SERCA2, actin, and CaMKII were found during neither P1 nor P2. Thus, the present study demonstrates that a second period of intense training leads to improved short-term performance and further improved RE, whereas 10-km performance and VO 2 -max improve to the same extent as during the first period. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Vibration test and endurance test for HANARO 36-element fuel assembly

International Nuclear Information System (INIS)

Ryu, Jeong Soo; Kim, Heon ll; Chung, Heung June

1998-06-01

Vibration test and endurance test for HANARO DU (depleted uranium) 36-element fuel assembly which was fabricated by KAERI were carried out based on the HANARO operation conditions. The endurance test of 22 days was added to the previous 18 days test. The vibration test was performed at various flow rates. Vibration frequency for the 36-element fuel assembly is between 11 to 14.5 Hz. And the maximum vibration displacement is less than 100 μm. From the endurance test result, it can be concluded that the appreciable fretting wear for the 36-element fuel assembly and the hexagonal flow tube was not observed. (author). 4 refs., 5 tabs., 29 figs

Low Proportion of Dietary Plant Protein among Athletes with Premenstrual Syndrome-Related Performance Impairment.

Science.gov (United States)

Yamada, Keiko; Takeda, Takashi

2018-02-01

Premenstrual syndrome (PMS) is psychosomatic disorder that are limited to the late luteal phase in the menstrual cycle. PMS could impair athletic performance. To investigate associations between proportions of dietary plant and animal protein and PMS-related impairment of athletic performance, we surveyed 135 female athletes aged 18-23 years attending Kindai University. Participants belonged to authorized university clubs, all of which have high rankings in Japanese university sports. Participants completed self-administered questionnaires on diet history, demographics, and PMS-related impairment of athletic performance. Total protein, animal protein, and plant protein intake were examined, and the proportion of dietary plant protein was calculated for each participant. We divided athletes into two groups: those without PMS-related impairment of athletic performance (n = 117) and those with PMS-related performance impairment (n = 18). A t-test was used to compare mean values and multivariable adjusted mean values between groups; adjustment variables were energy intake, body mass index, and daily training duration. Total protein intake was not significantly different between the groups. However, athletes whose performance was affected by PMS reported higher intake of animal protein (mean 50.6 g) than athletes whose performance was unaffected by PMS (mean 34.9 g). Plant protein intake was lower among athletes with PMS-related impairment (mean 25.4 g) than among athletes without impairment (mean 26.9 g). The proportion of dietary plant protein was lower among athletes with PMS-related impairment (39.3%) than those without impairment (45.9%). A low proportion of dietary plant protein may cause PMS-related athletic impairment among athletes.

Evidence that communication impairment in schizophrenia is associated with generalized poor task performance.

Science.gov (United States)

Merrill, Anne M; Karcher, Nicole R; Cicero, David C; Becker, Theresa M; Docherty, Anna R; Kerns, John G

2017-03-01

People with schizophrenia exhibit wide-ranging cognitive deficits, including slower processing speed and decreased cognitive control. Disorganized speech symptoms, such as communication impairment, have been associated with poor cognitive control task performance (e.g., goal maintenance and working memory). Whether communication impairment is associated with poorer performance on a broader range of non-cognitive control measures is unclear. In the current study, people with schizophrenia (n =51) and non-psychiatric controls (n =26) completed speech interviews allowing for reliable quantitative assessment of communication impairment. Participants also completed multiple goal maintenance and working memory tasks. In addition, we also examined (a) simple measures of processing speed involving highly automatic prepotent responses and (b) a non-cognitive control measure of general task performance. Schizophrenia communication impairment was significantly associated with poor performance in all cognitive domains, with the largest association found with processing speed (r s =-0.52). Further, communication impairment was also associated with the non-cognitive control measure of poor general task performance (r s =-0.43). In contrast, alogia, a negative speech symptom, and positive symptoms were less if at all related to cognitive task performance. Overall, this study suggests that communication impairment in schizophrenia may be associated with relatively generalized poor cognitive task performance. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Sarcopenia and impairment in cognitive and physical performance

Directory of Open Access Journals (Sweden)

Tolea MI

2015-03-01

Full Text Available Magdalena I Tolea,1 James E Galvin1–3 1Alzheimer’s Disease Center, Department of Neurology, 2Department of Psychiatry, 3Department of Population Health, New York University School of Medicine, New York, NY, USA Background: Whether older adults with sarcopenia who underperform controls on tests of physical performance and cognition also have a higher likelihood of combined cognitive-physical impairment is not clear. We assessed the impact of sarcopenia on impairment in both aspects of functionality and the relative contribution of its components, muscle mass and strength.Methods: Two hundred and twenty-three community-dwelling adults aged 40 years and older (mean age =68.1±10.6 years; 65% female were recruited and underwent physical functionality, anthropometry, and cognitive testing. Participants with low muscle mass were categorized as pre-sarcopenic; those with low muscle mass and muscle strength as sarcopenic; those with higher muscle mass and low muscle strength only were categorized as non-sarcopenic and were compared on risk of cognitive impairment (Montreal Cognitive Assessment <26; Ascertaining Dementia 8 ≥2, physical impairment (Mini Physical Performance Test <12, both, or neither by ordinal logistic regression. Results: Compared to controls, those with sarcopenia were six times more likely to have combined cognitive impairment/physical impairment with a fully adjusted model showing a three-fold increased odds ratio. The results were consistent across different measures of global cognition (odds ratio =3.46, 95% confidence interval =1.07–11.45 for the Montreal Cognitive Assessment; odds ratio =3.61, 95% confidence interval =1.11–11.72 for Ascertaining Dementia 8. Pre-sarcopenic participants were not different from controls. The effect of sarcopenia on cognition is related to low muscle strength rather than low muscle mass. Conclusion: Individuals with sarcopenia are not only more likely to have single but also to have dual

Increasing Endurance by Building Fluency: Precision Teaching Attention Span.

Science.gov (United States)

Binder, Carl; And Others

1990-01-01

Precision teaching techniques can be used to chart students' attention span or endurance. Individual differences in attention span can then be better understood and dealt with effectively. The effects of performance duration on performance level, on error rates, and on learning rates are discussed. Implications for classroom practice are noted.…

Visual-motor integration performance in children with severe specific language impairment.

Science.gov (United States)

Nicola, K; Watter, P

2016-09-01

This study investigated (1) the visual-motor integration (VMI) performance of children with severe specific language impairment (SLI), and any effect of age, gender, socio-economic status and concomitant speech impairment; and (2) the relationship between language and VMI performance. It is hypothesized that children with severe SLI would present with VMI problems irrespective of gender and socio-economic status; however, VMI deficits will be more pronounced in younger children and those with concomitant speech impairment. Furthermore, it is hypothesized that there will be a relationship between VMI and language performance, particularly in receptive scores. Children enrolled between 2000 and 2008 in a school dedicated to children with severe speech-language impairments were included, if they met the criteria for severe SLI with or without concomitant speech impairment which was verified by a government organization. Results from all initial standardized language and VMI assessments found during a retrospective review of chart files were included. The final study group included 100 children (males = 76), from 4 to 14 years of age with mean language scores at least 2SD below the mean. For VMI performance, 52% of the children scored below -1SD, with 25% of the total group scoring more than 1.5SD below the mean. Age, gender and the addition of a speech impairment did not impact on VMI performance; however, children living in disadvantaged suburbs scored significantly better than children residing in advantaged suburbs. Receptive language scores of the Clinical Evaluation of Language Fundamentals was the only score associated with and able to predict VMI performance. A small subgroup of children with severe SLI will also have poor VMI skills. The best predictor of poor VMI is receptive language scores on the Clinical Evaluation of Language Fundamentals. Children with poor receptive language performance may benefit from VMI assessment and multidisciplinary

The right ventricle following prolonged endurance exercise: are we overlooking the more important side of the heart? A meta-analysis.

Science.gov (United States)

Elliott, Adrian D; La Gerche, Andre

2015-06-01

Prolonged endurance exercise is associated with elevated biomarkers associated with myocardial damage and modest evidence of left ventricular (LV) dysfunction. Recent studies have reported more profound effects on right ventricular (RV) function following endurance exercise. We performed a meta-analysis of studies reporting RV function pre-endurance and postendurance exercise. We performed a search of peer-reviewed studies with the criteria for inclusion in the analysis being (1) healthy adult participants; (2) studies examining RV function following an event of at least 90 min duration; (3) studies reporting RV fractional area change (RVFAC), RV strain (S), RV ejection fraction (RVEF) or tricuspid annular plane systolic excursion (TAPSE) and (4) studies evaluating RV function immediately (exercise. Fourteen studies were included with 329 participants. A random-effects meta-analysis revealed significant impairments of RV function when assessed by RVFAC (weighted mean difference (WMD) -5.78%, 95% CI -7.09% to -4.46%), S (WMD 3.71%, 95% CI 2.79% to 4.63%), RVEF (WMD -7.05%, 95% CI -12.3% to -1.8%) and TAPSE (WMD -4.77 mm, 95% CI -8.3 to -1.24 mm). Modest RV dilation was evident in studies reporting RV systolic area postexercise (WMD 1.79 cm(2), 95% CI 0.5 to 3.08 cm(2)). In contrast, no postexercise changes in LV systolic function (expressed as LVFAC or LVEF) were observed in the included studies (standardised mean difference 0.03%, 95% CI -0.13% to 0.18%). Intense prolonged exercise is associated with a measurable reduction in RV function while LV function is relatively unaffected. Future studies should examine the potential clinical consequences of repeated prolonged endurance exercise on the right ventricle. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Medial temporal lobe damage impairs representation of simple stimuli

Directory of Open Access Journals (Sweden)

David E Warren

2010-05-01

Full Text Available Medial temporal lobe damage in humans is typically thought to produce a circumscribed impairment in the acquisition of new enduring memories, but recent reports have documented deficits even in short-term maintenance. We examined possible maintenance deficits in a population of medial temporal lobe amnesics, with the goal of characterizing their impairments as either representational drift or outright loss of representation over time. Patients and healthy comparisons performed a visual search task in which the similarity of various lures to a target was varied parametrically. Stimuli were simple shapes varying along one of several visual dimensions. The task was performed in two conditions, one presenting a sample target simultaneously with the search array and the other imposing a delay between sample and array. Eye-movement data collected during search revealed that the duration of fixations to items varied with lure-target similarity for all participants, i.e., fixations were longer for items more similar to the target. In the simultaneous condition, patients and comparisons exhibited an equivalent effect of similarity on fixation durations. However, imposing a delay modulated the effect differently for the two groups: in comparisons, fixation duration to similar items was exaggerated; in patients, the original effect was diminished. These findings indicate that medial temporal lobe lesions subtly impair short-term maintenance of even simple stimuli, with performance reflecting not the complete loss of the maintained representation but rather a degradation or progressive drift of the representation over time.

Endurance Exercise Ability in the Horse: A Trait with Complex Polygenic Determinism.

Science.gov (United States)

Ricard, Anne; Robert, Céline; Blouin, Christine; Baste, Fanny; Torquet, Gwendoline; Morgenthaler, Caroline; Rivière, Julie; Mach, Nuria; Mata, Xavier; Schibler, Laurent; Barrey, Eric

2017-01-01

Endurance horses are able to run at more than 20 km/h for 160 km (in bouts of 30-40 km). This level of performance is based on intense aerobic metabolism, effective body heat dissipation and the ability to endure painful exercise. The known heritabilities of endurance performance and exercise-related physiological traits in Arabian horses suggest that adaptation to extreme endurance exercise is influenced by genetic factors. The objective of the present genome-wide association study (GWAS) was to identify single nucleotide polymorphisms (SNPs) related to endurance racing performance in 597 Arabian horses. The performance traits studied were the total race distance, average race speed and finishing status (qualified, eliminated or retired). We used three mixed models that included a fixed allele or genotype effect and a random, polygenic effect. Quantile-quantile plots were acceptable, and the regression coefficients for actual vs. expected log 10 p -values ranged from 0.865 to 1.055. The GWAS revealed five significant quantitative trait loci (QTL) corresponding to 6 SNPs on chromosomes 6, 1, 7, 16, and 29 (two SNPs) with corrected p -values from 1.7 × 10 -6 to 1.8 × 10 -5 . Annotation of these 5 QTL revealed two genes: sortilin-related VPS10-domain-containing receptor 3 ( SORCS3 ) on chromosome 1 is involved in protein trafficking, and solute carrier family 39 member 12 ( SLC39A12 ) on chromosome 29 is active in zinc transport and cell homeostasis. These two coding genes could be involved in neuronal tissues (CNS). The other QTL on chromosomes 6, 7, and 16 may be involved in the regulation of the gene expression through non-coding RNAs, CpG islands and transcription factor binding sites. On chromosome 6, a new candidate equine long non-coding RNA ( KCNQ1OT1 ortholog: opposite antisense transcript 1 of potassium voltage-gated channel subfamily Q member 1 gene) was predicted in silico and validated by RT-qPCR in primary cultures of equine myoblasts and fibroblasts

Endurance Exercise Ability in the Horse: A Trait with Complex Polygenic Determinism

Directory of Open Access Journals (Sweden)

Anne Ricard

2017-06-01

Full Text Available Endurance horses are able to run at more than 20 km/h for 160 km (in bouts of 30–40 km. This level of performance is based on intense aerobic metabolism, effective body heat dissipation and the ability to endure painful exercise. The known heritabilities of endurance performance and exercise-related physiological traits in Arabian horses suggest that adaptation to extreme endurance exercise is influenced by genetic factors. The objective of the present genome-wide association study (GWAS was to identify single nucleotide polymorphisms (SNPs related to endurance racing performance in 597 Arabian horses. The performance traits studied were the total race distance, average race speed and finishing status (qualified, eliminated or retired. We used three mixed models that included a fixed allele or genotype effect and a random, polygenic effect. Quantile-quantile plots were acceptable, and the regression coefficients for actual vs. expected log10p-values ranged from 0.865 to 1.055. The GWAS revealed five significant quantitative trait loci (QTL corresponding to 6 SNPs on chromosomes 6, 1, 7, 16, and 29 (two SNPs with corrected p-values from 1.7 × 10−6 to 1.8 × 10−5. Annotation of these 5 QTL revealed two genes: sortilin-related VPS10-domain-containing receptor 3 (SORCS3 on chromosome 1 is involved in protein trafficking, and solute carrier family 39 member 12 (SLC39A12 on chromosome 29 is active in zinc transport and cell homeostasis. These two coding genes could be involved in neuronal tissues (CNS. The other QTL on chromosomes 6, 7, and 16 may be involved in the regulation of the gene expression through non-coding RNAs, CpG islands and transcription factor binding sites. On chromosome 6, a new candidate equine long non-coding RNA (KCNQ1OT1 ortholog: opposite antisense transcript 1 of potassium voltage-gated channel subfamily Q member 1 gene was predicted in silico and validated by RT-qPCR in primary cultures of equine myoblasts and

Acute and Post-Exercise Physiological Responses to High-Intensity Interval Training in Endurance and Sprint Athletes

Science.gov (United States)

Cipryan, Lukas; Tschakert, Gerhard; Hofmann, Peter

2017-01-01

The purpose of the presented study was to compare acute and post-exercise differences in cardiorespiratory, metabolic, cardiac autonomic, inflammatory and muscle damage responses to high-intensity interval exercise (HIIT) between endurance and sprint athletes. The study group consisted of sixteen highly-trained males (age 22.1 ± 2.5 years) participating in endurance (n = 8) or sprint (n = 8) sporting events. All the participants underwent three exercise sessions: short HIIT (work interval duration 30s), long HIIT (3min) and constant load exercise (CE). The exercise interventions were matched for mean power, total time and in case of HIIT interventions also for work-to-relief ratio. The acute cardiorespiratory (HR, V̇O2, RER) and metabolic (lactate) variables as well as the post-exercise changes (up to 3 h) in the heart rate variability, inflammation (interleukin-6, leucocytes) and muscle damage (creatine kinase, myoglobin) were monitored. Endurance athletes performed exercise interventions with moderately (CE) or largely (both HIIT modes) higher mean V̇O2. These differences were trivial/small when V̇O2 was expressed as a percentage of V̇O2max. Moderately to largely lower RER and lactate values were found in endurance athletes. Markers of cardiac autonomic regulation, inflammation and muscle damage did not reveal any considerable differences between endurance and sprint athletes. In conclusions, endurance athletes were able to perform both HIIT formats with increased reliance on aerobic metabolic pathways although exercise intensity was identical in relative terms for all the participants. However, other markers of the acute and early post-exercise physiological response to these HIIT interventions indicated similarities between endurance and sprint athletes. Key points The manner in which each training background (endurance vs. sprint) influences the response to HIIT is not well known. Despite the identical exercise intensity in relative terms, endurance

The effects of creatine and glycerol hyperhydration on running economy in well trained endurance runners

Directory of Open Access Journals (Sweden)

Beis Lukas Y

2011-12-01

Full Text Available Abstract Background Ingestion of creatine (Cr and glycerol (Gly has been reported to be an effective method in expanding water compartments within the human body, attenuating the rise in heart rate (HR and core temperature (Tcore during exercise in the heat. Despite these positive effects, a substantial water retention could potentially impair endurance performance through increasing body mass (BM and consequently impacting negatively on running economy (RE. The objective of the present study was to investigate the effects of a combined Cr and Gly supplementation on thermoregulatory and cardiovascular responses and RE during running for 30 min at speed corresponding to 60% of maximal oxygen uptake (V˙O2max in hot and cool conditions. Methods Cr·H2O (11.4 g, Gly (1 g·kg-1 BM and Glucose polymer (75 g were administered twice daily to 15 male endurance runners during a 7-day period. Exercise trials were conducted pre- and post-supplementation at 10 and 35°C and 70% relative humidity. Results BM and total body water increased by 0.90 ± 0.40 kg (P P V˙O2 and therefore RE. Both HR and Tcore were attenuated significantly after supplementation (P Conclusions Combining Cr and Gly is effective in reducing thermal and cardiovascular strain during exercise in the heat without negatively impacting on RE.

Free-piston Stirling engine/linear alternator 1000-hour endurance test

Science.gov (United States)

Rauch, J.; Dochat, G.

1985-01-01

The Free Piston Stirling Engine (FPSE) has the potential to be a long lived, highly reliable, power conversion device attractive for many product applications such as space, residential or remote site power. The purpose of endurance testing the FPSE was to demonstrate its potential for long life. The endurance program was directed at obtaining 1000 operational hours under various test conditions: low power, full stroke, duty cycle and stop/start. Critical performance parameters were measured to note any change and/or trend. Inspections were conducted to measure and compare critical seal/bearing clearances. The engine performed well throughout the program, completing more than 1100 hours. Hardware inspection, including the critical clearances, showed no significant change in hardware or clearance dimensions. The performance parameters did not exhibit any increasing or decreasing trends. The test program confirms the potential for long life FPSE applications.

Timing and gender determine if acute pain impairs working memory performance.

Science.gov (United States)

Hood, Anna; Pulvers, Kim; Spady, Thomas J

2013-11-01

The effects of pain on memory are complex, and little is known about the vulnerability of working memory (WM) performance when individuals complete a WM test while concurrently experiencing pain. Here, we subjected 78 healthy nonsmoking participants to either acute pain or a control condition while we administered a WM test. In this context, we also tested WM 20 minutes after pain in order to determine if timing of pain affected WM performance, and assessed objective and subjective measures of pain. We hypothesized that pain would impair WM performance during pain. Further, women's WM performance would be impaired more than men. Importantly, there was an interaction between gender and condition, with women exposed to pain experiencing impairments during but not after the cold pressor task. Our data imply that timing and gender are critically important in whether acute pain is costly to WM performance. Our findings have interesting clinical, professional, and educational implications, and understanding the influence of pain could help to improve the interpretation of WM tests in these diverse settings. Results of this study support the growing body of work that attests to the detrimental effect of pain on WM performance. Further, this study provides new evidence that concurrently experiencing cold pressor pain impairs WM in regularly menstruating women and women taking a contraceptive. Copyright © 2013 American Pain Society. Published by Elsevier Inc. All rights reserved.

Endurance testing with Li/Na electrolyte

Energy Technology Data Exchange (ETDEWEB)

Ong, E.T.; Remick, R.J.; Sishtla, C.I. [Institute of Gas Technology, Des Plaines, IL (United States)

1996-12-31

The Institute of Gas Technology (IGT), under subcontract to M-C Power Corporation under DOE funding, has been operating bench-scale fuel cells to investigate the performance and endurance issues of the Li/Na electrolyte because it offers higher ionic conductivity, higher exchange current densities, lower vapor pressures, and lower cathode dissolution rates than the Li/K electrolyte. These cells have continued to show higher performance and lower decay rates than the Li/K cells since the publication of our two previous papers in 1994. In this paper, test results of two long-term 100-cm{sup 2} bench scale cells are discussed. One cell operated continuously at 160 mA/cm{sup 2} for 17,000 hours with reference gases (60H{sub 2}/20CO{sub 2}/20H{sub 2}O fuel at 75% utilization and 30CO{sub 2}/70 air oxidant humidified at room temperature at 50% utilization). The other cell operated at 160 mA/cm{sup 2} for 6900 hours at 3 atm with system gases (64H{sub 2}/16CO{sub 2}/20H{sub 2}O at 75% utilization and an M-C Power system-defined oxidant at 40% utilization). Both cells have shown the highest performance and longest endurance among IGT cells operated to date.

Differences in muscle mechanical properties between elite power and endurance athletes: a comparative study.

Science.gov (United States)

Loturco, Irineu; Gil, Saulo; Laurino, Cristiano Frota de Souza; Roschel, Hamilton; Kobal, Ronaldo; Cal Abad, Cesar C; Nakamura, Fabio Y

2015-06-01

The aim of this study was to compare muscle mechanical properties (using tensiomyography-TMG) and jumping performance of endurance and power athletes and to quantify the associations between TMG parameters and jumping performance indices. Forty-one high-level track and field athletes from power (n = 22; mean ± SD age, height, and weight were 27.2 ± 3.6 years; 180.2 ± 5.4 cm; and 79.4 ± 8.6 kg, respectively) and endurance (endurance runners and triathletes; n = 19; mean ± SD age, height, and weight were 27.1 ± 6.9 years; 169.6 ± 9.8 cm; 62.2 ± 13.1 kg, respectively) specialties had the mechanical properties of their rectus femoris (RF) and biceps femoris (BF) assessed by TMG. Muscle displacement (Dm), contraction time (Tc), and delay time (Td) were retained for analyses. Furthermore, they performed squat jumps (SJs), countermovement jumps (CMJs), and drop jumps to assess reactive strength index (RSI), using a contact platform. Comparisons between groups were performed using differences based on magnitudes, and associations were quantified by the Spearman's ρ correlation. Power athletes showed almost certain higher performance in all jumping performance indices when compared with endurance athletes (SJ = 44.9 ± 4.1 vs. 30.7 ± 6.8 cm; CMJ = 48.9 ± 4.5 vs. 33.6 ± 7.2 cm; RSI = 2.19 ± 0.58 vs. 0.84 ± 0.39, for power and endurance athletes, mean ± SD, respectively; 00/00/100, almost certain, p ≤ 0.05), along with better contractile indices reflected by lower Dm, Tc, and Td (Tc BF = 14.3 ± 2.3 vs. 19.4 ± 3.3 milliseconds; Dm BF = 1.67 ± 1.05 vs. 4.23 ± 1.75 mm; Td BF = 16.8 ± 1.6 vs. 19.6 ± 1.3 milliseconds; Tc RF = 18.3 ± 2.8 vs. 22.9 ± 4.0 milliseconds; Dm RF = 4.98 ± 3.71 vs. 8.88 ± 3.45 mm; Td RF = 17.5 ± 1.0 vs. 20.9 ± 1.6 milliseconds, for power and endurance athletes, mean ± SD, respectively; 00/00/100, almost certain, p ≤ 0.05). Moderate correlations (Spearman's ρ between -0.61 and -0.72) were found between TMG and jumping

Simulated Evaluation of Drug-Impaired Psychomotor Performance

OpenAIRE

Richmond R

2014-01-01

The purpose of this placebo-controlled, randomized-crossover study was to evaluate a computer-based divided-attention task as a method for measure impaired human psychomotor performance. The ability of the divided-attention task to detect and differentiate was evaluated using single oral doses of placebo, caffeine and diphenhydramine. Ten healthy men were the subjects of the study. Subject performance on divided-attention was compared with tests of short-term memory and a set of visual analog...

Do Running Kinematic Characteristics Change over a Typical HIIT for Endurance Runners?

Science.gov (United States)

García-Pinillos, Felipe; Soto-Hermoso, Víctor M; Latorre-Román, Pedro Á

2016-10-01

García-Pinillos, F, Soto-Hermoso, VM, and Latorre-Román, PÁ. Do running kinematic characteristics change over a typical HIIT for endurance runners?. J Strength Cond Res 30(10): 2907-2917, 2016-The purpose of this study was to describe kinematic changes that occur during a common high-intensity intermittent training (HIIT) session for endurance runners. Twenty-eight male endurance runners participated in this study. A high-speed camera was used to measure sagittal-plane kinematics at the first and the last run during a HIIT (4 × 3 × 400 m). The dependent variables were spatial-temporal variables, joint angles during support and swing, and foot strike pattern. Physiological variables, rate of perceived exertion, and athletic performance were also recorded. No significant changes (p ≥ 0.05) in kinematic variables were found during the HIIT session. Two cluster analyses were performed, according to the average running pace-faster vs. slower, and according to exhaustion level reached-exhausted group vs. nonexhausted group (NEG). At first run, no significant differences were found between groups. As for the changes induced by the running protocol, significant differences (p ≤ 0.05) were found between faster and slower athletes at toe-off in θhip and θknee, whereas some changes were found in NEG in θhip during toe-off (+4.3°) and θknee at toe-off (-5.2°) during swing. The results show that a common HIIT session for endurance runners did not consistently or substantially perturb the running kinematics of trained male runners. Additionally, although some differences between groups have been found, neither athletic performance nor exhaustion level reached seems to be determinant in the kinematic response during a HIIT, at least for this group of moderately trained endurance runners.

COMBINED STRENGTH AND ENDURANCE TRAINING IN COMPETITIVE SWIMMERS

Directory of Open Access Journals (Sweden)

Stian Aspenes

2009-09-01

Full Text Available A combined intervention of strength and endurance training is common practice in elite swimming training, but the scientific evidence is scarce. The influences between strength and endurance training have been investigated in other sports but the findings are scattered. Some state the interventions are negative to each other, some state there is no negative relationship and some find bisected and supplementary benefits from the combination when training is applied appropriately. The aim of this study was to investigate the impact of a combined intervention among competitive swimmers. 20 subjects assigned to a training intervention group (n = 11 or a control group (n = 9 from two different teams completed the study. Anthropometrical data, tethered swimming force, land strength, performance in 50m, 100m and 400m, work economy, peak oxygen uptake, stroke length and stroke rate were investigated in all subjects at pre- and post-test. A combined intervention of maximal strength and high aerobic intensity interval endurance training 2 sessions per week over 11 weeks in addition to regular training were used, while the control group continued regular practice with their respective teams. The intervention group improved land strength, tethered swimming force and 400m freestyle performance more than the control group. The improvement of the 400m was correlated with the improvement of tethered swimming force in the female part of the intervention group. No change occurred in stroke length, stroke rate, performance in 50m or 100m, swimming economy or peak oxygen uptake during swimming. Two weekly dry-land strength training sessions for 11 weeks increase tethered swimming force in competitive swimmers. This increment further improves middle distance swimming performance. 2 weekly sessions of high- intensity interval training does not improve peak oxygen uptake compared with other competitive swimmers

Gender differences in alcohol impairment of simulated driving performance and driving-related skills.

Science.gov (United States)

Miller, Melissa A; Weafer, Jessica; Fillmore, Mark T

2009-01-01

Considerable laboratory research indicates that moderate doses of alcohol impair a broad range of skilled activities related to driving performance in young adults. Although laboratory studies show that the intensity of impairment is generally dependent on the blood alcohol concentration, some reviews of this literature suggest that women might be more sensitive to the impairing effects of alcohol than men. The present study tested this hypothesis. Drawing on data from previous experiments in our laboratory, we compared men and women in terms of the degree to which a challenge dose of alcohol (0.65 g/kg) impaired their simulated driving performance and measures of three separate behavioral and cognitive functions important to driving performance: motor coordination, speed of information processing and information-processing capacity. Alcohol significantly impaired all aspects of performance. Moreover, women displayed greater impairment than men on all behavioral tests and also reported higher levels of subjective intoxication compared with men. Both biological and social-cultural factors have been implicated in gender differences in the behavioral responses to alcohol. The current evidence of heightened sensitivity to alcohol in women highlights the need for better understanding the biological and environmental factors underlying this gender difference.

Responsiveness of the Countermovement Jump and Handgrip Strength to an Incremental Running Test in Endurance Athletes: Influence of Sex.

Science.gov (United States)

García-Pinillos, Felipe; Delgado-Floody, Pedro; Martínez-Salazar, Cristian; Latorre-Román, Pedro Á

2018-03-01

The present study analyzed the acute effects of an incremental running test on countermovement jump (CMJ) and handgrip strength performance in endurance athletes, considering the effect of post-exercise recovery time and sex. Thirty-three recreationally trained long-distance runners, 20 men and 13 women, participated voluntarily in this study. The participants performed the Léger test, moreover, the CMJ and handgrip strength tests were carried out before and after the running test and during different stages of recovery (at the 1st min of recovery (posttest1), 5th min of recovery (posttest2), and 10th min of recovery (posttest3)). Two-way analysis of variance revealed a significant improvement in the CMJ (pre-posttest1, p = 0.001) and handgrip strength (pre-posttest2, p = 0.017) during recovery time. The Pearson's Chi-2 test showed no significant relationship ( p ≥ 0.05) between sex and post-activation potentiation (PAP). A linear regression analysis pointed to heart rate recovery as a predictive factor of CMJ improvement (PAP). In conclusion, despite significant fatigue reached during the Léger test, the long-distance runners did not experience an impaired CMJ and handgrip strength performance, either men or women, achieving an improvement (PAP) in posttest conditions. The results obtained showed no significant relationship between sex and PAP. Moreover, significant effect of recovery after running at high intensity on CMJ performance and handgrip strength was found. Finally, the data suggest that PAP condition can be predicted by heart rate recovery in endurance runners.

Physical Performance Measures of Flexibility, Hip Strength, Lower Limb Power and Trunk Endurance in Healthy Navy Cadets: Normative Data and Differences Between Sex and Limb Dominance.

Science.gov (United States)

Lopes, Thiago Jambo Alves; Simic, Milena; Alves, Daniel de Souza; Bunn, Priscila Dos Santos; Rodrigues, Allan Inoue; Terra, Bruno de Souza; Lima, Maicom da Silva; Ribeiro, Fabrício Miranda; Vilão, Patrick; Pappas, Evangelos

2018-01-17

The objectives were to provide normative data on commonly used physical performance tests that may be associated with musculoskeletal injuries in Navy cadets, and assess for sex and limb dominance differences. A large cohort of Navy cadets were assessed for physical performance tests of flexibility (ankle dorsiflexion range of motion and sit and reach), isometric hip strength, lower limb power (single leg hop), and trunk endurance (plank and side plank tests). Besides providing normative data tables, sex and limb dominance differences were assessed by a two-way mixed ANOVA. A total of 545 Brazilian Navy cadets (394 males) representing 79% of the cadets in the Academy participated. Normative reference values were reported as mean±SD, 95%CI and percentiles. For tests of muscle strength, power and endurance, males performed better than females (p<0.001). For flexibility tests, females achieved greater distances than males for the sit and reach test (p<0.001), but no difference for ankle dorsiflexion (p=0.51). Overall, there were no clinically relevant differences between limbs. In conclusion, normative data for commonly used physical performance tests were provided. Although no clinically relevant side-to-side differences were found, males presented higher values for lower limb strength and power, as well as trunk endurance than females, while females demonstrated increased flexibility. Valuable normative data are provided to professionals who work with young, active populations from the injury prevention or rehabilitation perspective; as the current study may help professionals to identify athletes or cadets whose performance is outside the normative values and may be at risk for injury.

'The engine just started coughing!' - Limits of physical performance, aging and career continuity in elite endurance sports.

Science.gov (United States)

Ronkainen, Noora J; Ryba, Tatiana V; Nesti, Mark S

2013-12-01

This research examines male endurance athletes' experience of aging and/or reaching the perceived limits of physical performance. More specifically, the current study aimed to explore how existential meanings attached to these experiences are connected with athletes' decision-making concerning career continuity and retirement. Life story interviews were conducted with 10 Finnish runners and/or orienteers aged between 25 and 62 and the data was analyzed with an existential-narrative framework. Four major storylines related to aging were identified: The end of an era, putting things in perspective, the attitude has to change and winning was never the only motive. Our results suggest that endurance athletes possess diverse ways of bringing meaning to the experience of aging, both confirming and resisting the dominant cultural narrative of decline. While three athletes' stories confirmed the normativity of retirement when unable to improve their results anymore, other athletes demonstrated career continuity and positive aspects in the late career years, such as lack of competitive anxiety, finding perspective and increased enjoyment in running. We suggest that through awareness of alternative narratives, sport psychology consultants may be able to help their clients to explore new meanings in the potentially challenging and beneficial experiences of aging and athletic retirement. © 2013.

Interval endurance capacity of talented youth soccer players

NARCIS (Netherlands)

Visscher, C; Elferink-Gemser, MT; Lemmink, KAPM

The purpose of this study, in which 113 talented Youth soccer players (M = 16.0 yr., SD = 15), selected by their age and level of performance participated, was to investigate interval endurance capacity needed to play at the highest level of competition in the age-category 12 through 18.

Skeletal muscle adaptation and performance responses to once a day versus twice every second day endurance training regimens.

Science.gov (United States)

Yeo, Wee Kian; Paton, Carl D; Garnham, Andrew P; Burke, Louise M; Carey, Andrew L; Hawley, John A

2008-11-01

We determined the effects of a cycle training program in which selected sessions were performed with low muscle glycogen content on training capacity and subsequent endurance performance, whole body substrate oxidation during submaximal exercise, and several mitochondrial enzymes and signaling proteins with putative roles in promoting training adaptation. Seven endurance-trained cyclists/triathletes trained daily (High) alternating between 100-min steady-state aerobic rides (AT) one day, followed by a high-intensity interval training session (HIT; 8 x 5 min at maximum self-selected effort) the next day. Another seven subjects trained twice every second day (Low), first undertaking AT, then 1-2 h later, the HIT. These training schedules were maintained for 3 wk. Forty-eight hours before and after the first and last training sessions, all subjects completed a 60-min steady-state ride (60SS) followed by a 60-min performance trial. Muscle biopsies were taken before and after 60SS, and rates of substrate oxidation were determined throughout this ride. Resting muscle glycogen concentration (412 +/- 51 vs. 577 +/- 34 micromol/g dry wt), rates of whole body fat oxidation during 60SS (1,261 +/- 247 vs. 1,698 +/- 174 micromol.kg(-1).60 min(-1)), the maximal activities of citrate synthase (45 +/- 2 vs. 54 +/- 1 mmol.kg dry wt(-1).min(-1)), and beta-hydroxyacyl-CoA-dehydrogenase (18 +/- 2 vs. 23 +/- 2 mmol.kg dry wt(-1).min(-1)) along with the total protein content of cytochrome c oxidase subunit IV were increased only in Low (all P every second day compromised high-intensity training capacity. While selected markers of training adaptation were enhanced with twice a day training, the performance of a 1-h time trial undertaken after a 60-min steady-state ride was similar after once daily or twice every second day training programs.

Combined supplementation of carbohydrate, alanine, and proline is effective in maintaining blood glucose and increasing endurance performance during long-term exercise in mice.

Science.gov (United States)

Nogusa, Yoshihito; Mizugaki, Ami; Hirabayashi-Osada, Yuri; Furuta, Chie; Ohyama, Kana; Suzuki, Katsuya; Kobayashi, Hisamine

2014-01-01

Carbohydrate supplementation is extremely important during prolonged exercise because it maintains blood glucose levels during later stages of exercise. In this study, we examined whether maintaining blood glucose levels by carbohydrate supplementation could be enhanced during long-term exercise by combining this supplementation with alanine and proline, which are gluconeogenic amino acids, and whether such a combination would affect exercise endurance performance. Male C57BL/6J mice were orally administered either maltodextrin (1.25 g/kg) or maltodextrin (1.0 g/kg) with alanine (0.225 g/kg) and proline (0.025 g/kg) 15 min before running for 170 min. Combined supplementation of maltodextrin, alanine, and proline induced higher blood glucose levels than isocaloric maltodextrin alone during the late exercise phase (100-170 min). The hepatic glycogen content of mice administered maltodextrin, alanine, and proline was higher than that of mice ingesting maltodextrin alone 60 min after beginning exercise, but the glycogen content of the gastrocnemius muscle showed no difference. We conducted a treadmill running test to determine the effect of alanine and proline on endurance performance. The test showed that running time to exhaustion of mice that were supplemented with maltodextrin (2.0 g/kg) was longer than that of mice that were supplemented with water alone. Maltodextrin supplementation (1.0 g/kg) with alanine (0.9 g/kg) and proline (0.1 g/kg) further increased running time to exhaustion compared to maltodextrin alone (2.0 g/kg). These results indicate that combined supplementation of carbohydrate, alanine, and proline is effective for maintaining blood glucose and hepatic glycogen levels and increasing endurance performance during long-term exercise in mice.

Suplementação de carboidrato não reverte o efeito deletério do exercício de endurance sobre o subseqüente desempenho de força Suministrar carbohidratos no revierte el efecto destructivo del ejercicio de endurance sobre el subsiguiente desempeño de fuerza Carbohydrate supplementation fails to revert the deleterious effects of endurance exercise upon subsequent strength performance

Directory of Open Access Journals (Sweden)

Marcelo Saldanha Aoki

2003-10-01

ólicos inducidos por el ejercicio de endurance. Nuestro objetivo fue verificar si el ingerir carbohidratos (CHO puede atenuar los efectos de una sesión aguda de ejercicio de endurance sobre el desempeño de fuerza. Con el fin de verificar esta hipótesis, 6 estudiantes universitarias (164 ± 5,9cm; 64,9 ± 7,2kg, con experiencia en entrenamiento de fuerza, fueron sometidas a un test para determinar el VO2pico (44 ± 4,3ml.min-1 y a un test de 1-RM para leg press (186 ± 22,5kg seguido de un test de repeticiones máximas (2 series de leg press realizado a 70% de 1-RM hasta el cansancio 1ª serie 21 ± 2,6 y 2ª serie 11 ± 1,9 repeticiones en días diferentes. Siguiendo un procedimiento doble-ciego los voluntarios fueron sometidos a dos condiciones experimentales, recibiendo una bebida placebo (P u otra conteniendo carbohidratos (6% - maltodextrina, antes (500ml y durante (500ml la realización de una sesión de ejercicio de endurance (carrera en trotadores, 70% de VO2pico por 45 minutos. Después del ejercicio de endurance, los voluntarios realizaron un test de 1-RM seguido del test de repeticiones máximas. No se observaron cambios en el test de 1-RM o en la concentración plasmática de glicosis entre las condiciones experimentales (P x CHO. El número de repeticiones máximas a 70%-1RM presentó disminución en ambas situaciones (P 1ª serie 13 ± 2,9 reps y 2ª serie 6 ± 2,1 reps; CHO 1ª serie 15 ± 2,5 reps y 2ª serie 7 ± 1,7 reps, p Previous studies indicated that endurance exercise might have an adverse effect on subsequent strength performance. The decrease in strength performance might be related to the changes promoted by endurance exercise in energy metabolism. Authors' aim was verify if carbohydrate (CHO feeding can attenuate the effects of endurance exercise on strength development. To verify that hypothesis, six female university students (164 ± 5.9 cm; 64.9 ± 7.2 kg with strength training experience were submitted to a VO2peak test (44 ± 4.3 ml.min-1 and an

Acute short-term dim light exposure can lower muscle strength endurance

OpenAIRE

Arnold G. Nelson; Joke Kokkonen; Megan Mickenberg

2015-01-01

Background: Since it has been shown that spending 18 h under dim light conditions can result in reduced handgrip endurance, it was questioned whether or not a shorter exposure to dim light (i.e., 1 h) would have similar influence upon muscular endurance. Therefore this study compared the number of weighted knee extension lifts that could be done after spending 1 h in either dim or bright light. Methods: Participants (5 women, 11 men, college students 19–26 years) performed knee extension l...

The communicative performance of a severely hearing-impaired adolescent

Directory of Open Access Journals (Sweden)

Ann Russel

1981-11-01

Full Text Available This study describes the communicative performance of a severely hearing-impaired adolescent.The experimenter taught the subject how to play Russian Backgammon. The subject conversed with, and afterwards taught his mother, speech therapist, and a peer how to play the game. Each dyad played the game once. Videotape recordings were made of each dyadic situation. The channels of communication, both verbal and nonverbal, used by each speaker, were determined. A relational communication coding scheme, involving the analysis of requests and subsequent responses, was applied to the data. Results indicate that the hearing-impaired adolescent, though not always able to hold a dominant position in a dyadic situation, was capable of expressing the same types of control as normal adults. Moreover, the types of control expressed varied as a function of each contextual setting. Whenever the subject did hold a dominant position, the combined verbal plus nonverbal channel was his predominant mode of  communication. These findings  suggest that a sociolinguistic approach provides important information regarding a hearing-impaired adolescent's communicative performance.

Characterisation of baroreflex sensitivity of recreational ultra-endurance athletes.

Science.gov (United States)

Foulds, Heather J A; Cote, Anita T; Phillips, Aaron A; Charlesworth, Sarah A; Bredin, Shannon S D; Burr, Jamie F; Drury, Chipman Taylor; Ngai, Shirley; Fougere, Renee J; Ivey, Adam C; Warburton, Darren E R

2014-01-01

Altered autonomic function has been identified following ultra-endurance event participation among elite world-class athletes. Despite dramatic increases in recreational athlete participation in these ultra-endurance events, the physiological effects on these athletes are less known. This investigation sought to characterise changes in surrogate measures of autonomic function: heart rate variability (HRV), blood pressure variability (BPV) and baroreceptor sensitivity (BRS) following ultra-endurance race participation. Further, we sought to compare baseline measures among ultra-endurance athletes and recreationally active controls not participating in the ultra-endurance race. Recreational ultra-endurance athletes (n = 25, 44.6 ± 8.2 years, 8 females) and recreationally active age, sex and body mass index matched controls (n = 25) were evaluated. Measurements of HRV, BPV and BRS were collected pre- and post-race for recreational ultra-endurance athletes and at baseline, for recreationally active controls. Post-race, ultra-endurance athletes demonstrated significantly greater sympathetic modulation [low frequency (LF) power HRV: 50.3 ± 21.6 normalised units (n.u.) to 65.9 ± 20.4 n.u., p = 0.01] and significantly lower parasympathetic modulation [high frequency (HF) power HRV: 45.0 ± 22.4 n.u. to 23.9 ± 13.1 n.u., p HRV and BPV measures. Recreational ultra-endurance athletes experienced increased sympathetic tone and declines in BRS post-race, similar to previously reported elite world-class ultra-endurance athletes, though still within normal population ranges.

Endurance performance and energy metabolism during exercise in mice with a muscle-specific defect in the control of branched-chain amino acid catabolism.

Science.gov (United States)

Xu, Minjun; Kitaura, Yasuyuki; Ishikawa, Takuya; Kadota, Yoshihiro; Terai, Chihaya; Shindo, Daichi; Morioka, Takashi; Ota, Miki; Morishita, Yukako; Ishihara, Kengo; Shimomura, Yoshiharu

2017-01-01

It is known that the catabolism of branched-chain amino acids (BCAAs) in skeletal muscle is suppressed under normal and sedentary conditions but is promoted by exercise. BCAA catabolism in muscle tissues is regulated by the branched-chain α-keto acid (BCKA) dehydrogenase complex, which is inactivated by phosphorylation by BCKA dehydrogenase kinase (BDK). In the present study, we used muscle-specific BDK deficient mice (BDK-mKO mice) to examine the effect of uncontrolled BCAA catabolism on endurance exercise performance and skeletal muscle energy metabolism. Untrained control and BDK-mKO mice showed the same performance; however, the endurance performance enhanced by 2 weeks of running training was somewhat, but significantly less in BDK-mKO mice than in control mice. Skeletal muscle of BDK-mKO mice had low levels of glycogen. Metabolome analysis showed that BCAA catabolism was greatly enhanced in the muscle of BDK-mKO mice and produced branched-chain acyl-carnitine, which induced perturbation of energy metabolism in the muscle. These results suggest that the tight regulation of BCAA catabolism in muscles is important for homeostasis of muscle energy metabolism and, at least in part, for adaptation to exercise training.

Endurance performance and energy metabolism during exercise in mice with a muscle-specific defect in the control of branched-chain amino acid catabolism.

Directory of Open Access Journals (Sweden)

Minjun Xu

Full Text Available It is known that the catabolism of branched-chain amino acids (BCAAs in skeletal muscle is suppressed under normal and sedentary conditions but is promoted by exercise. BCAA catabolism in muscle tissues is regulated by the branched-chain α-keto acid (BCKA dehydrogenase complex, which is inactivated by phosphorylation by BCKA dehydrogenase kinase (BDK. In the present study, we used muscle-specific BDK deficient mice (BDK-mKO mice to examine the effect of uncontrolled BCAA catabolism on endurance exercise performance and skeletal muscle energy metabolism. Untrained control and BDK-mKO mice showed the same performance; however, the endurance performance enhanced by 2 weeks of running training was somewhat, but significantly less in BDK-mKO mice than in control mice. Skeletal muscle of BDK-mKO mice had low levels of glycogen. Metabolome analysis showed that BCAA catabolism was greatly enhanced in the muscle of BDK-mKO mice and produced branched-chain acyl-carnitine, which induced perturbation of energy metabolism in the muscle. These results suggest that the tight regulation of BCAA catabolism in muscles is important for homeostasis of muscle energy metabolism and, at least in part, for adaptation to exercise training.

Life-long endurance exercise in humans

DEFF Research Database (Denmark)

Mikkelsen, U R; Couppé, C; Karlsen, A

2013-01-01

Human aging is associated with a loss of skeletal muscle and an increase in circulating inflammatory markers. It is unknown whether endurance training (Tr) can prevent these changes. Therefore we studied 15 old trained (O-Tr) healthy males and, for comparison, 12 old untrained (O-Un), 10 Young.......05). Most importantly, life-long endurance exercise was associated with a lower level of the inflammatory markers CRP and IL-6 (p... physical endurance activity may play a role in reducing some markers of systemic inflammation, even within the normal range, and in maintaining muscle mass with aging....

Moderate-intensity endurance training improves endothelial glycocalyx layer integrity in healthy young men.

Science.gov (United States)

Majerczak, Joanna; Grandys, Marcin; Duda, Krzysztof; Zakrzewska, Agnieszka; Balcerczyk, Aneta; Kolodziejski, Leszek; Szymoniak-Chochol, Dorota; Smolenski, Ryszard T; Bartosz, Grzegorz; Chlopicki, Stefan; Zoladz, Jerzy A

2017-01-01

What is the central question of this study? The main aim of the present study was to determine the effect of prolonged moderate-intensity endurance training on the endothelial glycocalyx layer integrity in relationship to the training-induced changes in oxidative stress and antioxidant defence in humans. What is the main finding and its importance? We have shown, for the first time, a protective effect of prolonged moderate-intensity endurance training on endothelial glycocalyx layer integrity, as judged by significantly lower basal and end-exercise serum concentrations of glycocalyx damage markers, i.e. syndecan-1 and heparan sulfate, accompanied by attenuation of oxidative stress and enhancement of antioxidant defence after training in previously untrained healthy young men. In this study, we evaluated the effect of 20 weeks of moderate-intensity endurance training (ET) on the endothelial glycocalyx layer integrity in relationship to the training-induced changes in antioxidant defence. Eleven healthy young, untrained men performed an incremental cycling exercise bout until exhaustion before and after 20 weeks of ET. Endurance training consisted of 40 min sessions, mainly of moderate intensity (∼50% of maximal oxygen uptake), performed four times per week. Venous blood samples were taken at rest and at the end of the maximal exercise test. Muscle biopsies from vastus lateralis were taken before and after the training. Endurance training resulted in a significant increase in physical capacity (P  0.05). Moderate-intensity ET exerts a pronounced protective effect on endothelial glycocalyx integrity at rest and during exercise, probably through an improvement of antioxidant defence that may represent the vasoprotective mechanisms highly responsive to moderate-intensity endurance training. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.

Impact of Dietary Antioxidants on Sport Performance: A Review.

Science.gov (United States)

Braakhuis, Andrea J; Hopkins, Will G

2015-07-01

Many athletes supplement with antioxidants in the belief this will reduce muscle damage, immune dysfunction and fatigue, and will thus improve performance, while some evidence suggests it impairs training adaptations. Here we review the effect of a range of dietary antioxidants and their effects on sport performance, including vitamin E, quercetin, resveratrol, beetroot juice, other food-derived polyphenols, spirulina and N-acetylcysteine (NAC). Older studies suggest vitamin E improves performance at altitude, with possible harmful effects on sea-level performance. Acute intake of vitamin E is worthy of further consideration, if plasma levels can be elevated sufficiently. Quercetin has a small beneficial effect for exercise of longer duration (>100 min), but it is unclear whether this benefits athletes. Resveratrol benefits trained rodents; more research is needed in athletes. Meta-analysis of beetroot juice studies has revealed that the nitrate component of beetroot juice had a substantial but unclear effect on performance when averaged across athletes, non-athletes and modes of exercise (single dose 1.4 ± 2.0%, double dose 0.5 ± 1.9%). The effect of addition of polyphenols and other components to beetroot juice was trivial but unclear (single dose 0.4 ± 3.2%, double dose -0.5 ± 3.3%). Other food-derived polyphenols indicate a range of performance outcomes from a large improvement to moderate impairment. Limited evidence suggests spirulina enhances endurance performance. Intravenous NAC improved endurance cycling performance and reduced muscle fatigue. On the basis of vitamin E and NAC studies, acute intake of antioxidants is likely to be beneficial. However, chronic intakes of most antioxidants have a harmful effect on performance.

Uzobo, Endurance

African Journals Online (AJOL)

Uzobo, Endurance. Vol 11, No 1 (2016) - Articles Population and development in Nigeria: An assesment of the National Policy on Population and Sustainable Development Abstract PDF · Vol 12, No 1 (2017) - Articles Kin networks and migration in Sagbama Local Government Area of Bayelsa State Abstract PDF.

Four weeks of speed endurance training reduces energy expenditure during exercise and maintains muscle oxidative capacity despite a reduction in training volume

DEFF Research Database (Denmark)

Iaia, F. Marcello; Hellsten, Ylva; Nielsen, Jens Jung

2009-01-01

We studied the effect of an alteration from regular endurance to speed endurance training on muscle oxidative capacity, capillarization, as well as energy expenditure during submaximal exercise and its relationship to mitochondrial uncoupling protein 3 (UCP3) in humans. Seventeen endurance...... by lowered mitochondrial UCP3 expression. Furthermore, speed endurance training can maintain muscle oxidative capacity, capillarization, and endurance performance in already trained individuals despite significant reduction in the amount of training....

Contraction-mediated glucose uptake is increased in men with impaired glucose tolerance

DEFF Research Database (Denmark)

Skov-Jensen, Camilla; Skovbro, Mette; Flint, Anne

2007-01-01

stimulation alone and with superimposed exercise. Patients with type 2 diabetes, subjects with impaired glucose tolerance (IGT), healthy controls, and endurance-trained subjects were studied. The groups were matched for age and lean body mass (LBM), and differed in peak oxygen uptake (VO2 peak), body fat...

Veterinary problems of endurance horses in England and Wales.

Science.gov (United States)

Nagy, A; Dyson, S J; Murray, J K

2017-05-01

Several studies have shown that a considerable proportion of horses are eliminated from endurance rides due to lameness and metabolic problems. Limited information is available on specific veterinary issues in endurance horses and there are no descriptive data on veterinary problems in a large population of endurance horses. The aim of this study was to describe veterinary problems occurring in endurance horses in England and Wales, the regions of the United Kingdom where endurance rides are organised and regulated by Endurance Great Britain (Endurance GB). A comprehensive online self-completed questionnaire was used for data collection (30th December 2015-29th February 2016) All members of Endurance GB who were the main rider of one or more endurance horses were eligible to participate. From the target population of 1209 horses, 190 questionnaires were completed by riders, resulting in a 15.7% response rate. The most common rider-reported veterinary problem was lameness, affecting 152/190 (80.0%) of endurance horses at some point during their careers and 101/190 (53.2%) of horses in the previous 12 months. Detailed information on the most recent episode of lameness was available for 147 horses. Seventy-six percent of these lameness episodes (112/147) had been initially identified by a veterinarian, but only 52% of these lameness episodes were investigated further by a veterinarian, despite the high proportion of horses affected by lameness and the proportion of horses with recurrent lameness episodes. The second most common veterinary problem was thoracolumbar region pain, followed by non-specific cough, skin disease and colic. Education of endurance riders may improve the number, quality and timing of veterinary investigations, especially for lameness and thoracolumbar region pain. Copyright © 2017 Elsevier B.V. All rights reserved.

Solution-Space Screening of a Hypersonic Endurance Demonstrator

Science.gov (United States)

Chudoba, Bernd; Coleman, Gary; Oza, Amit; Gonzalez, Lex; Czysz, Paul

2012-01-01

This report documents a parametric sizing study performed to develop a program strategy for research and development and procurement of a feasible next-generation hypersonic air-breathing endurance demonstrator. Overall project focus has been on complementing technical and managerial decision-making during the earliest conceptual design phase towards minimization of operational, technical, and managerial risks.

Effect of salbutamol on neuromuscular function in endurance athletes.

Science.gov (United States)

Decorte, Nicolas; Bachasson, Damien; Guinot, Michel; Flore, Patrice; Levy, Patrick; Verges, Samuel; Wuyam, Bernard

2013-10-01

The potential ergogenic effects of therapeutic inhaled salbutamol doses in endurance athletes have been controversially discussed for decades. We hypothesized that salbutamol inhalation may increase peripheral muscle contractility, reduce fatigability, and improve force recovery after a localized exercise in endurance athletes. Eleven healthy, nonasthmatic male athletes with high aerobic capacities were recruited to be compared in a double-blinded, randomized crossover study of two dose levels of salbutamol (200 and 800 μg) and a placebo administered by inhalation before a quadriceps fatigue test. Subjects performed an incremental exercise protocol consisting in sets of 10 intermittent isometric contractions starting at 20% of maximum voluntary contraction (MVC) with 10% MVC increment until exhaustion. Femoral nerve magnetic stimulation was used during and after MVC to evaluate neuromuscular fatigue after each set, at task failure, and after 10 and 30 min of recovery. Initial MVC and evoked muscular responses were not modified with salbutamol (P > 0.05). The total number of submaximal contractions until task failure significantly differed between treatments (placebo, 72 ± 7; 200 µg, 78 ± 8; and 800 µg, 82 ± 7; P 0.05). Voluntary activation was unaffected by the fatiguing task and treatments (P > 0.05). Supratherapeutic inhaled doses of β2-agonists increased quadriceps endurance during an incremental and localized fatiguing task in healthy endurance-trained athletes without significant effect on neuromuscular fatigue. Further studies are needed to clarify the underlying mechanisms.

Menstrual Cycle Effects on Anaerobic Power, Muscular Strength, and Muscular Endurance in Trained and Untrained Females.

Science.gov (United States)

Rosenburg, Beth S.; And Others

A study determined if anaerobic power, isometric strength, and isometric endurance are affected by the menstrual cycle and if endurance trained females and untrained females are affected in the same manner on these performance parameters. Subjects were healthy, normally menstruating females, ages 18-34 years who were classified as either trained…

Visual Search Performance in Patients with Vision Impairment: A Systematic Review.

Science.gov (United States)

Senger, Cassia; Margarido, Maria Rita Rodrigues Alves; De Moraes, Carlos Gustavo; De Fendi, Ligia Issa; Messias, André; Paula, Jayter Silva

2017-11-01

Patients with visual impairment are constantly facing challenges to achieve an independent and productive life, which depends upon both a good visual discrimination and search capacities. Given that visual search is a critical skill for several daily tasks and could be used as an index of the overall visual function, we investigated the relationship between vision impairment and visual search performance. A comprehensive search was undertaken using electronic PubMed, EMBASE, LILACS, and Cochrane databases from January 1980 to December 2016, applying the following terms: "visual search", "visual search performance", "visual impairment", "visual exploration", "visual field", "hemianopia", "search time", "vision lost", "visual loss", and "low vision". Two hundred seventy six studies from 12,059 electronic database files were selected, and 40 of them were included in this review. Studies included participants of all ages, both sexes, and the sample sizes ranged from 5 to 199 participants. Visual impairment was associated with worse visual search performance in several ophthalmologic conditions, which were either artificially induced, or related to specific eye and neurological diseases. This systematic review details all the described circumstances interfering with visual search tasks, highlights the need for developing technical standards, and outlines patterns for diagnosis and therapy using visual search capabilities.

Effects of curative treatment emphasizing endurance training on the performance and blood pressure of hypertensive and normotensives

Science.gov (United States)

Worms, F.

1981-01-01

The problem of normal values of blood pressure after exercise taking into account the blood pressure at the end of the exercise test is discussed. Hypertensives showed a lower working capacity than normotensives. In normotensives, however, systolic blood pressure at the end of an exercise correlated well with the working capacity. After the endurance cure submaximal blood pressure was markedly lower in hypertensives with a striking dependence on the level of initial values. Systolic blood pressure at the end of an exercise test was not changed significantly. Most probably it is not possible to overcome this malregulation in hypertensives by endurance training alone.

[Comparison of cardiopulmonary endurance and muscular fitness in teenagers between Hong Kong and inland cities].

Science.gov (United States)

Hong, Y; Chan, K; Wang, Y

1997-01-01

A study on the data of the physique investigated in teenagers was carried out between Hong Kong and inland cities to compare their cardiopulmonary endurance and muscular fitness. Results revealed that cardiopulmonary endurance in school teenagers of both sex at different ages in inland cities was better than that in Hong Kong. Muscular strength and endurance of sports performance of teenagers, except for standing long jump, in Hong Kong were weaker than that in inland cities. It suggests that attention should be paid to the involvement of teenagers in physical education with the increase of people's living standard.

Acute and Post-Exercise Physiological Responses to High-Intensity Interval Training in Endurance and Sprint Athletes.

Science.gov (United States)

Cipryan, Lukas; Tschakert, Gerhard; Hofmann, Peter

2017-06-01

The purpose of the presented study was to compare acute and post-exercise differences in cardiorespiratory, metabolic, cardiac autonomic, inflammatory and muscle damage responses to high-intensity interval exercise (HIIT) between endurance and sprint athletes. The study group consisted of sixteen highly-trained males (age 22.1 ± 2.5 years) participating in endurance (n = 8) or sprint (n = 8) sporting events. All the participants underwent three exercise sessions: short HIIT (work interval duration 30s), long HIIT (3min) and constant load exercise (CE). The exercise interventions were matched for mean power, total time and in case of HIIT interventions also for work-to-relief ratio. The acute cardiorespiratory (HR, V̇ O 2 , RER) and metabolic (lactate) variables as well as the post-exercise changes (up to 3 h) in the heart rate variability, inflammation (interleukin-6, leucocytes) and muscle damage (creatine kinase, myoglobin) were monitored. Endurance athletes performed exercise interventions with moderately (CE) or largely (both HIIT modes) higher mean V̇ O 2 . These differences were trivial/small when V̇ O 2 was expressed as a percentage of V̇ O 2max . Moderately to largely lower RER and lactate values were found in endurance athletes. Markers of cardiac autonomic regulation, inflammation and muscle damage did not reveal any considerable differences between endurance and sprint athletes. In conclusions, endurance athletes were able to perform both HIIT formats with increased reliance on aerobic metabolic pathways although exercise intensity was identical in relative terms for all the participants. However, other markers of the acute and early post-exercise physiological response to these HIIT interventions indicated similarities between endurance and sprint athletes.

Acute and Post-Exercise Physiological Responses to High-Intensity Interval Training in Endurance and Sprint Athletes

Directory of Open Access Journals (Sweden)

Lukas Cipryan, Gerhard Tschakert, Peter Hofmann

2017-06-01

Full Text Available The purpose of the presented study was to compare acute and post-exercise differences in cardiorespiratory, metabolic, cardiac autonomic, inflammatory and muscle damage responses to high-intensity interval exercise (HIIT between endurance and sprint athletes. The study group consisted of sixteen highly-trained males (age 22.1 ± 2.5 years participating in endurance (n = 8 or sprint (n = 8 sporting events. All the participants underwent three exercise sessions: short HIIT (work interval duration 30s, long HIIT (3min and constant load exercise (CE. The exercise interventions were matched for mean power, total time and in case of HIIT interventions also for work-to-relief ratio. The acute cardiorespiratory (HR, V̇O2, RER and metabolic (lactate variables as well as the post-exercise changes (up to 3 h in the heart rate variability, inflammation (interleukin-6, leucocytes and muscle damage (creatine kinase, myoglobin were monitored. Endurance athletes performed exercise interventions with moderately (CE or largely (both HIIT modes higher mean V̇O2. These differences were trivial/small when V̇O2 was expressed as a percentage of V̇O2max. Moderately to largely lower RER and lactate values were found in endurance athletes. Markers of cardiac autonomic regulation, inflammation and muscle damage did not reveal any considerable differences between endurance and sprint athletes. In conclusions, endurance athletes were able to perform both HIIT formats with increased reliance on aerobic metabolic pathways although exercise intensity was identical in relative terms for all the participants. However, other markers of the acute and early post-exercise physiological response to these HIIT interventions indicated similarities between endurance and sprint athletes.

Association between vestibular function and motor performance in hearing-impaired children.

Science.gov (United States)

Maes, Leen; De Kegel, Alexandra; Van Waelvelde, Hilde; Dhooge, Ingeborg

2014-12-01

The clinical balance performance of normal-hearing (NH) children was compared with the balance performance of hearing-impaired (HI) children with and without vestibular dysfunction to identify an association between vestibular function and motor performance. Prospective study. Tertiary referral center. Thirty-six children (mean age, 7 yr 5 mo; range, 3 yr 8 mo-12 yr 11 mo) divided into three groups: NH children with normal vestibular responses, HI children with normal vestibular responses, and HI children with abnormal vestibular function. A vestibular test protocol (rotatory and collic vestibular evoked myogenic potential testing) in combination with three clinical balance tests (balance beam walking, one-leg hopping, one-leg stance). Clinical balance performance. HI children with abnormal vestibular test results obtained the lowest quotients of motor performance, which were significantly lower compared with the NH group (p beam walking and one-leg stance; p = 0.003 for one-leg hopping). The balance performance of the HI group with normal vestibular responses was better in comparison with the vestibular impaired group but still significantly lower compared with the NH group (p = 0.020 for balance beam walking; p = 0.001 for one-leg stance; not significant for one-leg hopping). These results indicate an association between vestibular function and motor performance in HI children, with a more distinct motor deterioration if a vestibular impairment is superimposed to the auditory dysfunction.

Effect of different protocols of caffeine intake on metabolism and endurance performance.

Science.gov (United States)

Cox, Gregory R; Desbrow, Ben; Montgomery, Paul G; Anderson, Megan E; Bruce, Clinton R; Macrides, Theodore A; Martin, David T; Moquin, Angela; Roberts, Alan; Hawley, John A; Burke, Louise M

2002-09-01

Competitive athletes completed two studies of 2-h steady-state (SS) cycling at 70% peak O(2) uptake followed by 7 kJ/kg time trial (TT) with carbohydrate (CHO) intake before (2 g/kg) and during (6% CHO drink) exercise. In Study A, 12 subjects received either 6 mg/kg caffeine 1 h preexercise (Precaf), 6 x 1 mg/kg caffeine every 20 min throughout SS (Durcaf), 2 x 5 ml/kg Coca-Cola between 100 and 120 min SS and during TT (Coke), or placebo. Improvements in TT were as follows: Precaf, 3.4% (0.2-6.5%, 95% confidence interval); Durcaf, 3.1% (-0.1-6.5%); and Coke, 3.1% (-0.2-6.2%). In Study B, eight subjects received 3 x 5 ml/kg of different cola drinks during the last 40 min of SS and TT: decaffeinated, 6% CHO (control); caffeinated, 6% CHO; decaffeinated, 11% CHO; and caffeinated, 11% CHO (Coke). Coke enhanced TT by 3.3% (0.8-5.9%), with all trials showing 2.2% TT enhancement (0.5-3.8%; P < 0.05) due to caffeine. Overall, 1) 6 mg/kg caffeine enhanced TT performance independent of timing of intake and 2) replacing sports drink with Coca-Cola during the latter stages of exercise was equally effective in enhancing endurance performance, primarily due to low intake of caffeine (approximately 1.5 mg/kg).

The effect of repeated periods of speed endurance training on performance, running economy and muscle adaptations

DEFF Research Database (Denmark)

Skovgaard, Casper; Almquist, Nicki Winfield; Bangsbo, Jens

2018-01-01

sessions during two 40-day periods (P1 and P2) separated by ~80 days of habitual training. Before and after both P1 and P2, subjects completed an incremental test to exhaustion to determine VO2 -max and a repeated running test at 90% vVO2 -max to exhaustion (RRT) to determine short-term endurance capacity......, with no change in P1. No changes in muscle expression of Na(+) ,K(+) -ATPase α1, α2 and β1, NHE1, SERCA1 and SERCA2, actin and CamKII were found during neither P1 nor P2. Thus, the present study demonstrates that a second period of intense training leads to improved short-term performance and further improved RE...

Impact of a supervised worksite exercise program on back and core muscular endurance in firefighters.

Science.gov (United States)

Mayer, John M; Quillen, William S; Verna, Joe L; Chen, Ren; Lunseth, Paul; Dagenais, Simon

2015-01-01

Low back pain is a leading cause of disability in firefighters and is related to poor muscular endurance. This study examined the impact of supervised worksite exercise on back and core muscular endurance in firefighters. A cluster randomized controlled trial was used for this study. The study occurred in fire stations of a municipal fire department (Tampa, Florida). Subjects were 96 full-duty career firefighters who were randomly assigned by fire station to exercise (n = 54) or control (n = 42) groups. Exercise group participants completed a supervised exercise targeting the back and core muscles while on duty, two times per week for 24 weeks, in addition to their usual fitness regimen. Control group participants continued their usual fitness regimen. Back and core muscular endurance was assessed with the Biering-Sorensen test and plank test, respectively. Changes in back and core muscular endurance from baseline to 24 weeks were compared between groups using analysis of covariance and linear mixed effects models. After 24 weeks, the exercise group had 12% greater (p = .021) back muscular endurance and 21% greater (p = .0006) core muscular endurance than did the control group. The exercise intervention did not disrupt operations or job performance. A supervised worksite exercise program was safe and effective in improving back and core muscular endurance in firefighters, which could protect against future low back pain.

Measurement of quadriceps endurance by fNIRS

Science.gov (United States)

Erdem, Devrim; Şayli, Ömer; Karahan, Mustafa; Akin, A.

2006-02-01

In this paper, the changes in muscle deoxygenation trends during a sustained isometric quadriceps (chair squat/half squat) endurance exercise were evaluated among twelve male subjects and the relationship between muscle oxygenation and endurance times was investigated by means of functional near-infrared spectroscopy (fNIRS). Neuromuscular activation and predictions of muscle performance decrements during extended fatiguing task was investigated by means of surface electromyography (sEMG). The results of the study showed that in the subjects who maintained exercise longer than five minutes (group 1), mean Hb recovery time (33 [sec.]) was 37.4% less than the others (group 2, 52.7 [sec.]). Also mean HbO II decline amplitude (2.53 [a.u.] in group 1 and 2.07 [a.u.] in group 2) and oxy decline amplitude (8.4 [a.u.] in group 1 and 3.04 [a.u.] in group 2) in the beginning of squat exercise are found to be 22.6% and 176.9% bigger in these group. For the EMG parameters, mean slope of MNF and MDF decline are found to be 57.5% and 42.2% bigger in magnitude in group 2 which indicates higher degree of decrement in mean and median frequencies although their mean squat duration time is less. This indicates higher index of fatigue for this group. It is concluded that training leads to altered oxygenation and oxygen extraction capability in the exercising muscle and investigated fNIRS parameters could be used for endurance evaluation.

Endurance Exercise in Hypoxia, Hyperoxia and Normoxia: Mitochondrial and Global Adaptations.

Science.gov (United States)

Przyklenk, Axel; Gutmann, Boris; Schiffer, Thorsten; Hollmann, Wildor; Strueder, Heiko K; Bloch, Wilhelm; Mierau, Andreas; Gehlert, Sebastian

2017-07-01

We hypothesized short-term endurance exercise (EN) in hypoxia (HY) to exert decreased mitochondrial adaptation, peak oxygen consumption (VO 2peak ) and peak power output (PPO) compared to EN in normoxia (NOR) and hyperoxia (PER). 11 male subjects performed repeated unipedal cycling EN in HY, PER, and NOR over 4 weeks in a cross-over design. VO 2peak , PPO, rate of perceived exertion (RPE) and blood lactate (Bla) were determined pre- and post-intervention to assess physiological demands and adaptation. Skeletal muscle biopsies were collected to determine molecular mitochondrial signaling and adaptation. Despite reduced exercise intensity (P0.05). Electron transport chain complexes tended to increase in all groups with the highest increase in HY (n.s.). EN-induced mitochondrial adaptability and exercise capacity neither decreased significantly in HY nor increased in PER compared to NOR. Despite decreased exercise intensity, short term EN under HY may not necessarily impair mitochondrial adaptation and exercise capacity while PER does not augment adaptation. HY might strengthen adaptive responses under circumstances when absolute training intensity has to be reduced. © Georg Thieme Verlag KG Stuttgart · New York.

Analysis of Tests Evaluating Sport Climbers’ Strength and Isometric Endurance

Directory of Open Access Journals (Sweden)

Ozimek Mariusz

2016-12-01

Full Text Available The present study was designed to determine which types of specific tests provide an effective evaluation of strength and endurance in highly trained competitive sport climbers. The research process consisted of three basic components: the measurement of selected somatic characteristics of the climbers, the assessment of their physical conditioning, and a search for correlations between the anthropometric and “conditioning” variables on the one hand, and climber’s performance on the other. The sample of subjects consisted of 14 experienced volunteer climbers capable of handling 7a- 8a+/b on-sight rock climbing grades. The strongest correlations (Spearman’s rank were found between climber’s competence and the relative results of the finger strength test (r = 0.7; much lower, but still statistically significant coefficients were found between the level of competence and the results of the muscle endurance tests (r = 0.53 – 0.57. Climbers aspiring to attain an elite level must have strong finger and forearm muscles, but most of all, they must be capable of releasing their potential during specific motor capability tests engaging these parts of the body. The forearm muscles of elite climbers must also be very resistant to fatigue. Since highly trained athletes vary only slightly in body mass, this variable does not have a major effect on their performance during strength and endurance tests.

How is goodwill impairment driven by relative firm performance? : evidence from Germany

OpenAIRE

Brandão, Sara Fontes Coutinho Mesquita

2014-01-01

Goodwill treatment has been facing considerable changes in terms of regulation. More recently, IAS 36 (2004) develops the subject of impairment of assets, stating that goodwill should be subject to impairment tests on an annual basis. In the IFRS context, the present research study aims at investigating how goodwill impairment is driven by relative firm performance in Europe, using Germany evidence. More precisely, the paper focuses on two distinct analyses: comparing differenc...

A power recirculating test rig for ball screw endurance tests

Directory of Open Access Journals (Sweden)

Giberti Hermes

2016-01-01

Full Text Available A conceptual design of an innovative test rig for endurance tests of ball screws is presented in this paper. The test rig layout is based on the power recirculating principle and it also allows to overtake the main critical issues of the ball screw endurance tests. Among these there are the high power required to make the test, the lengthy duration of the same and the high loads between the screw and the frame that holds it. The article describes the test rig designed scheme, the kinematic expedients to be adopted in order to obtain the required performance and functionality and the sizing procedure to choose the actuation system.

Effects of Plyometric Training and Beta-Alanine Supplementation on Maximal-Intensity Exercise and Endurance in Female Soccer Players

Directory of Open Access Journals (Sweden)

Rosas Fabián

2017-08-01

Full Text Available Plyometric training and beta-alanine supplementation are common among soccer players, although its combined use had never been tested. Therefore, a randomized, double-blind, placebo-controlled trial was conducted to compare the effects of a plyometric training program, with or without beta-alanine supplementation, on maximal-intensity and endurance performance in female soccer players during an in-season training period. Athletes (23.7 ± 2.4 years were assigned to either a plyometric training group receiving a placebo (PLACEBO, n = 8, a plyometric training group receiving beta-alanine supplementation (BA, n = 8, or a control group receiving placebo without following a plyometric training program (CONTROL, n = 9. Athletes were evaluated for single and repeated jumps and sprints, endurance, and change-of-direction speed performance before and after the intervention. Both plyometric training groups improved in explosive jumping (ES = 0.27 to 1.0, sprinting (ES = 0.31 to 0.78, repeated sprinting (ES = 0.39 to 0.91, 60 s repeated jumping (ES = 0.32 to 0.45, endurance (ES = 0.35 to 0.37, and change-of-direction speed performance (ES = 0.36 to 0.58, whereas no significant changes were observed for the CONTROL group. Nevertheless, compared to the CONTROL group, only the BA group showed greater improvements in endurance, repeated sprinting and repeated jumping performances. It was concluded that beta-alanine supplementation during plyometric training may add further adaptive changes related to endurance, repeated sprinting and jumping ability.

Effects of Plyometric Training and Beta-Alanine Supplementation on Maximal-Intensity Exercise and Endurance in Female Soccer Players.

Science.gov (United States)

Rosas, Fabián; Ramírez-Campillo, Rodrigo; Martínez, Cristian; Caniuqueo, Alexis; Cañas-Jamet, Rodrigo; McCrudden, Emma; Meylan, Cesar; Moran, Jason; Nakamura, Fábio Y; Pereira, Lucas A; Loturco, Irineu; Diaz, Daniela; Izquierdo, Mikel

2017-09-01

Plyometric training and beta-alanine supplementation are common among soccer players, although its combined use had never been tested. Therefore, a randomized, double-blind, placebo-controlled trial was conducted to compare the effects of a plyometric training program, with or without beta-alanine supplementation, on maximal-intensity and endurance performance in female soccer players during an in-season training period. Athletes (23.7 ± 2.4 years) were assigned to either a plyometric training group receiving a placebo (PLACEBO, n = 8), a plyometric training group receiving beta-alanine supplementation (BA, n = 8), or a control group receiving placebo without following a plyometric training program (CONTROL, n = 9). Athletes were evaluated for single and repeated jumps and sprints, endurance, and change-of-direction speed performance before and after the intervention. Both plyometric training groups improved in explosive jumping (ES = 0.27 to 1.0), sprinting (ES = 0.31 to 0.78), repeated sprinting (ES = 0.39 to 0.91), 60 s repeated jumping (ES = 0.32 to 0.45), endurance (ES = 0.35 to 0.37), and change-of-direction speed performance (ES = 0.36 to 0.58), whereas no significant changes were observed for the CONTROL group. Nevertheless, compared to the CONTROL group, only the BA group showed greater improvements in endurance, repeated sprinting and repeated jumping performances. It was concluded that beta-alanine supplementation during plyometric training may add further adaptive changes related to endurance, repeated sprinting and jumping ability.

Glycogen availability and skeletal muscle adaptations with endurance and resistance exercise

NARCIS (Netherlands)

Knuiman, Pim; Hopman, Maria T.E.; Mensink, Marco

2015-01-01

It is well established that glycogen depletion affects endurance exercise performance negatively. Moreover, numerous studies have demonstrated that post-exercise carbohydrate ingestion improves exercise recovery by increasing glycogen resynthesis. However, recent research into the effects of

Effects of Adolescent Sport Practice on Health Outcomes of Adult Amateur Endurance Cyclists: Adulthood Is Not Too Late to Start.

Science.gov (United States)

Munguia-Izquierdo, Diego; Mayolas-Pi, Carmen; Peñarrubia-Lozano, Carlos; Paris-Garcia, Federico; Bueno-Antequera, Javier; Oviedo-Caro, Miguel Angel; Legaz-Arrese, Alejandro

2017-11-01

We investigated the effects of adolescent sport practice on the training, performance, and health outcomes of adult amateur endurance cyclists and compared health outcomes of 3 adult groups: amateur endurance cyclists who practiced sports during adolescence, amateur endurance cyclists who did not practice sports during adolescence, and inactive individuals. In 859 (751 men and 108 women) adult cyclists and 718 inactive subjects (307 men and 411 women), we examined adolescent sport practice, current training status, quality of life, quality of sleep, anxiety and depression, and cardiometabolic risk: body mass index, physical activity, physical fitness, adherence to Mediterranean diet, and alcohol and tobacco consumption. Independent of gender, no significant differences in training, performance, or health outcomes were observed between amateur endurance cyclists who practiced sports during adolescence and those who did not. Independent of gender, cyclists reported significantly better health outcomes than inactive individuals in all variables, except depression. Training, performance, and health outcomes did not differ between adult amateur endurance cyclists who practiced sports during adolescence and those who did not, but their health outcomes were significantly improved compared with inactive individuals, except for depression.

Exercise performance and cardiovascular health variables in 70-year-old male soccer players compared to endurance-trained, strength-trained and untrained age-matched men

DEFF Research Database (Denmark)

Randers, Morten Bredsgaard; Andersen, Jesper Løvind; Petersen, Jesper

2014-01-01

Abstract The aim was to investigate performance variables and indicators of cardiovascular health profile in elderly soccer players (SP, n = 11) compared to endurance-trained (ET, n = 8), strength-trained (ST, n = 7) and untrained (UT, n = 7) age-matched men. The 33 men aged 65-85 years underwent...

Effects of endurance and endurance-strength exercise on biochemical parameters of liver function in women with abdominal obesity.

Science.gov (United States)

Skrypnik, Damian; Ratajczak, Marzena; Karolkiewicz, Joanna; Mądry, Edyta; Pupek-Musialik, Danuta; Hansdorfer-Korzon, Rita; Walkowiak, Jarosław; Jakubowski, Hieronim; Bogdański, Paweł

2016-05-01

Obesity is a risk factor of nonalcoholic fatty liver disease. Although the standard therapy for obesity involves physical exercise, well-planned studies of the changes in liver function in response to different exercise intensities in obese subjects are scarce. The aim of the present study was to examine a question of how does exercise mode affect the liver function. 44 women with abdominal obesity were randomized into two exercise groups: endurance (group A) and endurance-strength (group B). Women in each group exercised for 60min 3 times/week for a 3-month period. Markers of liver function: serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyltranspeptidase (GGT), alkaline phosphatase (ALP) activities, and bilirubin levels were quantified. We found significant differences in ALT (pexercise. Blood ALT and AST tended to decrease in group B, increase in group A. Significant reduction in serum GGT level after exercise in both groups was observed (pexercise led to changes in serum ALP activity and total or direct bilirubin level. However, endurance-strength training resulted in significant decreases in serum indirect bilirubin (pexercise (group B). The mode of exercise does matter: endurance-strength exercise led to a greater improvement, compared to endurance exercise, in the liver function in women with abdominal obesity. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Alterations in redox homeostasis in the elite endurance athlete.

Science.gov (United States)

Lewis, Nathan A; Howatson, Glyn; Morton, Katie; Hill, Jessica; Pedlar, Charles R

2015-03-01

The production of reactive oxygen (ROS) and nitrogen species (RNS) is a fundamental feature of mammalian physiology, cellular respiration and cell signalling, and essential for muscle function and training adaptation. Aerobic and anaerobic exercise results in alterations in redox homeostasis (ARH) in untrained, trained and well trained athletes. Low to moderate doses of ROS and RNS play a role in muscle adaptation to endurance training, but an overwhelming increase in RNS and ROS may lead to increased cell apoptosis and immunosuppression, fatigued states and underperformance. The objectives of this systematic review are: (a) to test the hypotheses that ARH occur in elite endurance athletes; following an acute exercise bout, in an endurance race or competition; across a micro-, meso- or macro-training cycle; following a training taper; before, during and after altitude training; in females with amenorrhoea versus eumenorrhoea; and in non-functional over-reaching (NFOR) and overtraining states (OTS); (b) to report any relationship between ARH and training load and ARH and performance; and (c) to apply critical difference values for measures of oxidative stress/ARH to address whether there is any evidence of ARH being of physiological significance (not just statistical) and thus relevant to health and performance in the elite athlete. Electronic databases, Embase, MEDLINE, and SPORTDiscus were searched for relevant articles. Only studies that were observational articles of cross-sectional or longitudinal design, and included elite athletes competing at national or international level in endurance sports were included. Studies had to include biomarkers of ARH; oxidative damage, antioxidant enzymes, antioxidant capacity, and antioxidant vitamins and nutrients in urine, serum, plasma, whole blood, red blood cells (RBCs) and white blood cells (WBCs). A total of 3,057 articles were identified from the electronic searches. Twenty-eight articles met the inclusion criteria

Two-agent cooperative search using game models with endurance-time constraints

Science.gov (United States)

Sujit, P. B.; Ghose, Debasish

2010-07-01

In this article, the problem of two Unmanned Aerial Vehicles (UAVs) cooperatively searching an unknown region is addressed. The search region is discretized into hexagonal cells and each cell is assumed to possess an uncertainty value. The UAVs have to cooperatively search these cells taking limited endurance, sensor and communication range constraints into account. Due to limited endurance, the UAVs need to return to the base station for refuelling and also need to select a base station when multiple base stations are present. This article proposes a route planning algorithm that takes endurance time constraints into account and uses game theoretical strategies to reduce the uncertainty. The route planning algorithm selects only those cells that ensure the agent will return to any one of the available bases. A set of paths are formed using these cells which the game theoretical strategies use to select a path that yields maximum uncertainty reduction. We explore non-cooperative Nash, cooperative and security strategies from game theory to enhance the search effectiveness. Monte-Carlo simulations are carried out which show the superiority of the game theoretical strategies over greedy strategy for different look ahead step length paths. Within the game theoretical strategies, non-cooperative Nash and cooperative strategy perform similarly in an ideal case, but Nash strategy performs better than the cooperative strategy when the perceived information is different. We also propose a heuristic based on partitioning of the search space into sectors to reduce computational overhead without performance degradation.

Respiratory Muscle Training and Exercise Endurance at Altitude.

Science.gov (United States)

Helfer, Samuel; Quackenbush, Joseph; Fletcher, Michael; Pendergast, David R

2016-08-01

Climbing and trekking at altitude are common recreational and military activities. Physiological effects of altitude are hypoxia and hyperventilation. The hyperventilatory response to altitude may cause respiratory muscle fatigue and reduce sustained submaximal exercise. Voluntary isocapnic hyperpnea respiratory muscle training (VIHT) improves exercise endurance at sea level and at depth. The purpose of this study was to test the hypothesis that VIHT would improve exercise time at altitude [3600 m (11,811 ft)] compared to control and placebo groups. Subjects pedaled an ergometer until exhaustion at simulated altitude in a hypobaric chamber while noninvasive arterial saturation (Sao2), ventilation (VE), and oxygen consumption (Vo2) were measured. As expected, Sao2 decreased to 88 ± 4% saturation at rest and to 81 ± 2% during exercise, and was not affected by VIHT. VIHT resulted in a 40% increase in maximal training VE compared to pre-VIHT. Exercise endurance significantly increased 44% after VIHT (P = altitude post-VIHT increased more (49%) for longer (21 min) and decreased less (11% at 25.4 ± 6.7 min). VIHT improved exercise time at altitude and sustained VE. This suggests that VIHT reduced respiratory muscle fatigue and would be useful to trekkers and military personnel working at altitude. Helfer S, Quackenbush J, Fletcher M, Pendergast DR. Respiratory muscle training and exercise endurance at altitutde. Aerosp Med Hum Perform. 2016; 87(8):704-711.

No improvement in race performance by naps in male ultra-endurance cyclists in a 600-km ultra-cycling race.

Science.gov (United States)

Knechtle, Beat; Wirth, Andrea; Knechtle, Patrizia; Rüst, Christoph Alexander; Rosemann, Thomas; Lepers, Romuald

2012-04-30

Ultra-endurance performance is of increasing popularity. We investigated the associations between anthropometry, training and support during racing, with race performance in 67 male recreational ultra-endurance cyclists participating in the 'Swiss Cycling Marathon' over 600 kilometres, an official qualifier for the cycling ultra-marathon 'Paris-Brest-Paris'. The 54 finishers showed no differences in anthropometry and did not train differently compared to the 13 non-finishers. During the race, the finishers were significantly more frequently racing alone than being followed by a support crew. After bivariate analysis, percent body fat (r = 0.43), the cycling distance per training unit (r = -0.36), the duration per training unit (r = -0.31) and the sleep time during the race (r = 0.50) were related to overall race time. The 23 non-sleepers in the finisher group completed the race within (mean and IQR) 1,567 (1,453-1,606) min, highly significantly faster than the 31 sleepers with 1,934 (1,615-2,033) min (P = 0.0003). No variable of support during the race was associated with race time. After multivariate analysis, percent body fat (P = 0.026) and duration per training unit (P = 0.005) remained predictor variables for race time. To summarize, for a successful finish in a cycling ultra-marathon over 600 kilometres such as the 'Swiss Cycling Marathon', percent body fat and duration per training unit were related to race time whereas equipment and support during the race showed no association. Athletes with naps were highly significantly slower than athletes without naps.

Maximal fat oxidation rates in endurance trained and untrained women

DEFF Research Database (Denmark)

Stisen, A.B.; Stougaard, O.; Langfort, J.

2006-01-01

The aim of the present study was to examine the differences in fat oxidation between endurance trained (ET) and untrained (UT) women. Eight ET and nine UT women performed a progressive cycle ergometer test until exhaustion. The rate of fat oxidation was similar at low work rates (...

High-intensity lower limb endurance training in chronic respiratory disease

OpenAIRE

Tanaka, Takako; Arizono, Shinichi; Hanada, Masatoshi; Senjyu, Hideaki

2015-01-01

High-intensity endurance training is mainly undertaken during pulmonary rehabilitation for patients with chronic respiratory disease. High-intensity endurance training is recommended in many clinical management guidelines. High-intensity endurance training involves training generally at an intensity of at 60-80％ of the patient’s peak work capacity or higher. The effects of high-intensity lower limb endurance training have mostly been investigated in chronic obstructive pulmonary disease （COPD...

Metabolic Responses to Sago and Soy Supplementations during Endurance Cycling Performance in the Heat

Directory of Open Access Journals (Sweden)

Daniel Tarmast

2017-10-01

Full Text Available This study examined the effects of Sago (Sa, Soy (So, combined iso–caloric Sago+Soy (SS supplementations during cycling on metabolic responses as compared to placebo (P in the heat (31℃, 70% relative humidity. Twelve well–trained male cyclists (Age: 19.0±5.6 yr, Height: 170.8±7.6 cm, Wight: 60.1±11.2 kg, and VO2max: 56.5±6.5 mL.kg-1.min-1 participated in four experimental trials. The design of the trials was a randomized single–blind, placebo–controlled crossover trail comprising 90 min of steady–state cycling on an ergometer at 60% of VO2max followed by a 20–km time trial performance (TT. The participants of the study were supplemented 5 times at 0, 20, 40, 60, and 80 minutes during the steady–state cycling. Sa, So, and SS supplements provided 7.5% Sago, 7.5% Soy, and 6.0% Sago + 1.5% Soy respectively. Plasma glucose concentrations (PG reached a peak at 60 min after ingestion of Sa and SS as compared to baseline. At the end of the TT, PG reduced significantly to the baseline level. Plasma insulin concentrations (PI increased in all trials, but reduced gradually to the baseline level. The concentration of plasma free fatty acids (FFA increased gradually during the steady–state cycling and TT, and FFA was significantly higher in the P and So than the Sa and SS trials. At the end of the steady–state cycling, the plasma lactate concentration (LACT reached its lowest concentrations and at the end of the TT was enhanced significantly in all trials. These results suggest that sago and soy supplements increase the PG and PI during endurance exercise in the heat. These data add to the growing body of knowledge concerning endurance athletes’ glycemic and insulinemic responses to carbohydrate consumptions during exercise in the heat.

Impact of Age and Hearing Impairment on Work Performance during Long Working Hours

Directory of Open Access Journals (Sweden)

Verena Wagner-Hartl

2018-01-01

Full Text Available Based on demographic prognoses, it must be assumed that a greater number of older workers will be found in the future labor market. How to deal with their possible age-related impairments of sensory functions, like hearing impairment and work performance during extended working time, has not been addressed explicitly until now. The study addresses this interplay. The study was performed on two consecutive days after normal working hours. The 55 participants had to “work” in the study at least three additional hours to simulate a situation of long working hours. The tested measures for (job performance were: general attention, long-term selective attention, concentration, and reaction time. All of the investigated variables were taken at both days of the study (2 × 2 × 2 repeated measurement design. The results show effects for age, the interaction of hearing impairment and time of measurement, and effects of the measurement time. Older participants reacted slower than younger participants did. Furthermore, younger participants reacted more frequently in a correct way. Hearing impairment seems to have a negative impact especially on measures of false reactions, and therefore especially on measurement time 1. The results can be interpreted in a way that hearing-impaired participants are able to compensate their deficits over time.

Impact of Age and Hearing Impairment on Work Performance during Long Working Hours.

Science.gov (United States)

Wagner-Hartl, Verena; Grossi, Nina R; Kallus, K Wolfgang

2018-01-09

Based on demographic prognoses, it must be assumed that a greater number of older workers will be found in the future labor market. How to deal with their possible age-related impairments of sensory functions, like hearing impairment and work performance during extended working time, has not been addressed explicitly until now. The study addresses this interplay. The study was performed on two consecutive days after normal working hours. The 55 participants had to "work" in the study at least three additional hours to simulate a situation of long working hours. The tested measures for (job) performance were: general attention, long-term selective attention, concentration, and reaction time. All of the investigated variables were taken at both days of the study (2 × 2 × 2 repeated measurement design). The results show effects for age, the interaction of hearing impairment and time of measurement, and effects of the measurement time. Older participants reacted slower than younger participants did. Furthermore, younger participants reacted more frequently in a correct way. Hearing impairment seems to have a negative impact especially on measures of false reactions, and therefore especially on measurement time 1. The results can be interpreted in a way that hearing-impaired participants are able to compensate their deficits over time.

Testing the efficacy of existing force-endurance models to account for the prevalence of obesity in the workforce.

Science.gov (United States)

Pajoutan, Mojdeh; Cavuoto, Lora A; Mehta, Ranjana K

2017-10-01

This study evaluates whether the existing force-endurance relationship models are predictive of endurance time for overweight and obese individuals, and if not, provide revised models that can be applied for ergonomics practice. Data was collected from 141 participants (49 normal weight, 50 overweight, 42 obese) who each performed isometric endurance tasks of hand grip, shoulder flexion, and trunk extension at four levels of relative workload. Subject-specific fatigue rates and a general model of the force-endurance relationship were determined and compared to two fatigue models from the literature. There was a lack of fit between previous models and the current data for the grip (ICC = 0.8), with a shift toward lower endurance times for the new data. Application of the revised models can facilitate improved workplace design and job evaluation to accommodate the capacities of the current workforce.

The effects of postexercise consumption of a kefir beverage on performance and recovery during intensive endurance training.

Science.gov (United States)

O'Brien, K V; Stewart, L K; Forney, L A; Aryana, K J; Prinyawiwatkul, W; Boeneke, C A

2015-11-01

This study was designed to determine whether kefir accentuates the positive health benefits assessed by measures in fitness, body composition, or both, as a measure of cardiovascular disease risk as well as the biomarker C-reactive protein (CRP). Sixty-seven adult males and females aged 18 to 24 yr were assigned to 1 of 4 groups: (1) endurance training + control beverage, (2) endurance training +kefir beverage,(3) active control + control beverage, or (4) active control + kefir beverage. The exercise groups completed 15 wk of structured endurancetraining while the active control groups maintained their usual exercise routine. Additionally, each group was assigned to either a kefir or a calorie/macronutrient matched placebo beverage that was consumed twice per week. No significant interactions were found among groups with respect to outcome variables with the exception of serum CRP. The endurance training was effective in improving 1.5-mile (2.41 km) times and kefir supplementation may have been a factor in attenuating the increase in CRP that was observed over the course of the intervention period. This preliminary study suggests that kefir may be involved in improving the risk profile for cardiovascular disease as defined by CRP. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

[Endurance capabilities of triathlon competitors with type 1 diabetes mellitus].

Science.gov (United States)

Boehncke, S; Poettgen, K; Maser-Gluth, C; Reusch, J; Boehncke, W-H; Badenhoop, K

2009-04-01

Treatment of type 1 diabetes mellitus (DM) aims to prevent complications by strictly optimizing blood glucose levels. Although physical exercise is an important part of metabolic control, endurance sports are considered hazardous for patients with type 1 diabetes because of the extreme physiological stress they represent. To further elucidate the metabolic challenge this form of exercise presented we investigated the performance of triathlon competitors with type 1 diabetes. Ten patients (32-61 years) with type 1 diabetes (disease duration 2-35 years) were followed for three years, during which each year they participated in one triathlon long-distance competitions (2.4 miles swimming, 26.2 miles running and 112 miles cycling; Ironman Germany 2005-2007). Glucose, cortisol, aldosterone, renin, thyroid hormones, testosterone, growth hormone and catecholamines were measured in blood and saliva. Five non-diabetic competitors served as controls. The performance equalled those of age-matched healthy athletes. Several participants experienced hyperglycemia early in the bike leg, whereas all of them developed low blood glucose levels during the marathon leg. Basal insulin supply was reduced up to 50 % on race day. Hormone levels in athletes with type 1 DM and healthy controls were similar. Patients with type 1 DM can successfully sustain extreme endurance challenges. Physiological alterations of the metabolic state complicated by type 1 DM can readily be compensated by adapting intensified insulin therapy and nutritional modifications. Thus 1 DM should not be regarded a contraindication to participating in high endurance sports.

Individual Endurance Training Prescription with Heart Rate Variability.

Science.gov (United States)

Vesterinen, Ville; Nummela, Ari; Heikura, Ida; Laine, Tanja; Hynynen, Esa; Botella, Javier; Häkkinen, Keijo

2016-07-01

Measures of HR variability (HRV) have shown potential to be of use in training prescription. The aim of this study was to investigate the effectiveness of using HRV in endurance training prescription. Forty recreational endurance runners were divided into the HRV-guided experimental training group (EXP) and traditional predefined training group (TRAD). After a 4-wk preparation training period, TRAD trained according to a predefined training program including two to three moderate- (MOD) and high-intensity training (HIT) sessions per week during an 8-wk intensive training period. The timing of MOD and HIT sessions in EXP was based on HRV, measured every morning. The MOD/HIT session was programmed if HRV was within an individually determined smallest worthwhile change. Otherwise, low-intensity training was performed. Maximal oxygen consumption (V˙O2max) and 3000-m running performance (RS3000m) were measured before and after both training periods. The number of MOD and HIT sessions was significantly lower (P = 0.021, effect size = 0.98) in EXP (13.2 ± 6.0 sessions) compared with TRAD (17.7 ± 2.5 sessions). No other differences in training were found between the groups. RS3000m improved in EXP (2.1% ± 2.0%, P = 0.004) but not in TRAD (1.1% ± 2.7%, P = 0.118) during the intensive training period. A small between-group difference (effect size = 0.42) was found in the change in RS3000m. V˙O2max improved in both groups (EXP: 3.7% ± 4.6%, P = 0.027; TRAD: 5.0% ± 5.2%, P = 0.002). The results of the present study suggest the potential of resting HRV to prescribe endurance training by individualizing the timing of vigorous training sessions.

The sit up test to exhaustion as a test for muscular endurance evaluation.

Science.gov (United States)

Bianco, Antonino; Lupo, Corrado; Alesi, Marianna; Spina, Serena; Raccuglia, Margherita; Thomas, Ewan; Paoli, Antonio; Palma, Antonio

2015-01-01

The aim of this study was to examine the sit up test to exhaustion as a field test for muscular endurance evaluation in a sample of sedentary people of both sexes. A cross-sectional study was performed. Three-hundred-eighty-one participants volunteered for the study (28.5 ± 10.0 years; 168.2 ± 8.9 cm; 65.1 ± 11.1 kg), of which 194 males (27.5 ± 10.2 years; 173.6 ± 7.0 cm; 71.2 ± 5.2 kg) and 187 females (29.6 ± 10.1 years; 162.6 ± 7.1 cm; 58.7 ± 8.9 kg). Each subject voluntarily and randomly performed: a sit up test (SUT), a push up test (PUT), and a free weight squat test (ST), all till exhaustion. A multiple regression analysis was adopted for data analysis. Subsequently a percentile model for muscle endurance was developed. The 25th, 50th, and 75th percentile were identified as upper limit for low muscular endurance, average muscular endurance, and lower limit for high muscular endurance, respectively. Considering the sit up test as the dependent variable, the coefficients (R(2) = 0.23; r = 0.49; p squat test, respectively. Gender stratification showed regression coefficients of (R(2) = 0.19; r = 0.44; p < 0.001) for SUT vs. PUT, and (R(2) = 0.30; r = 0.56; p < 0.001) for SUT vs. ST in male; and (R(2) = 0.23; r = 0.49; p < 0.001) for SUT vs. PUT, and (R(2) = 0.34; r = 0.59; p < 0.001) for SUT vs. ST in female. The SUT showed low inter-relation with the other proposed tests indicating that the adoption of a single test for the global evaluation of muscle endurance is not the optimal approach. Moreover, the SUT was found to be inexpensive, safe, and appropriate for core muscle endurance measurement for both male and female.

How does high-intensity intermittent training affect recreational endurance runners? Acute and chronic adaptations: A systematic review

Directory of Open Access Journals (Sweden)

Felipe García-Pinillos

2017-03-01

Conclusion: HIIT-based running plans (2 to 3 HIIT sessions per week, combining HIIT and CR runs show athletic performance improvements in endurance runners by improving maximal oxygen uptake and running economy along with muscular and metabolic adaptations. To maximize the adaptations to training, both HIIT and CR must be part of training programs for endurance runners.

Physical Performance Is Associated with Working Memory in Older People with Mild to Severe Cognitive Impairment

Directory of Open Access Journals (Sweden)

K. M. Volkers

2014-01-01

Full Text Available Background. Physical performances and cognition are positively related in cognitively healthy people. The aim of this study was to examine whether physical performances are related to specific cognitive functioning in older people with mild to severe cognitive impairment. Methods. This cross-sectional study included 134 people with a mild to severe cognitive impairment (mean age 82 years. Multiple linear regression was performed, after controlling for covariates and the level of global cognition, with the performances on mobility, strength, aerobic fitness, and balance as predictors and working memory and episodic memory as dependent variables. Results. The full models explain 49–57% of the variance in working memory and 40–43% of episodic memory. Strength, aerobic fitness, and balance are significantly associated with working memory, explaining 3–7% of its variance, irrespective of the severity of the cognitive impairment. Physical performance is not related to episodic memory in older people with mild to severe cognitive impairment. Conclusions. Physical performance is associated with working memory in older people with cognitive impairment. Future studies should investigate whether physical exercise for increased physical performance can improve cognitive functioning. This trial is registered with ClinicalTrials.gov NTR1482.

The training intensity distribution among well-trained and elite endurance athletes

Science.gov (United States)

Stöggl, Thomas L.; Sperlich, Billy

2015-01-01

Researchers have retrospectively analyzed the training intensity distribution (TID) of nationally and internationally competitive athletes in different endurance disciplines to determine the optimal volume and intensity for maximal adaptation. The majority of studies present a “pyramidal” TID with a high proportion of high volume, low intensity training (HVLIT). Some world-class athletes appear to adopt a so-called “polarized” TID (i.e., significant % of HVLIT and high-intensity training) during certain phases of the season. However, emerging prospective randomized controlled studies have demonstrated superior responses of variables related to endurance when applying a polarized TID in well-trained and recreational individuals when compared with a TID that emphasizes HVLIT or threshold training. The aims of the present review are to: (1) summarize the main responses of retrospective and prospective studies exploring TID; (2) provide a systematic overview on TIDs during preparation, pre-competition, and competition phases in different endurance disciplines and performance levels; (3) address whether one TID has demonstrated greater efficacy than another; and (4) highlight research gaps in an effort to direct future scientific studies. PMID:26578968

Extended driving impairs nocturnal driving performances.

Directory of Open Access Journals (Sweden)

Patricia Sagaspe

Full Text Available Though fatigue and sleepiness at the wheel are well-known risk factors for traffic accidents, many drivers combine extended driving and sleep deprivation. Fatigue-related accidents occur mainly at night but there is no experimental data available to determine if the duration of prior driving affects driving performance at night. Participants drove in 3 nocturnal driving sessions (3-5 am, 1-5 am and 9 pm-5 am on open highway. Fourteen young healthy men (mean age [+/-SD] = 23.4 [+/-1.7] years participated Inappropriate line crossings (ILC in the last hour of driving of each session, sleep variables, self-perceived fatigue and sleepiness were measured. Compared to the short (3-5 am driving session, the incidence rate ratio of inappropriate line crossings increased by 2.6 (95% CI, 1.1 to 6.0; P<.05 for the intermediate (1-5 am driving session and by 4.0 (CI, 1.7 to 9.4; P<.001 for the long (9 pm-5 am driving session. Compared to the reference session (9-10 pm, the incidence rate ratio of inappropriate line crossings were 6.0 (95% CI, 2.3 to 15.5; P<.001, 15.4 (CI, 4.6 to 51.5; P<.001 and 24.3 (CI, 7.4 to 79.5; P<.001, respectively, for the three different durations of driving. Self-rated fatigue and sleepiness scores were both positively correlated to driving impairment in the intermediate and long duration sessions (P<.05 and increased significantly during the nocturnal driving sessions compared to the reference session (P<.01. At night, extended driving impairs driving performances and therefore should be limited.

Association of Neuromuscular Attributes With Performance-Based Mobility Among Community-Dwelling Older Adults With Symptomatic Lumbar Spinal Stenosis.

Science.gov (United States)

Schmidt, Catherine T; Ward, Rachel E; Suri, Pradeep; Kiely, Dan K; Ni, Pengsheng; Anderson, Dennis E; Bean, Jonathan F

2017-07-01

To identify differences in health factors, neuromuscular attributes, and performance-based mobility among community-dwelling older adults with symptomatic lumbar spinal stenosis; and to determine which neuromuscular attributes are associated with performance-based measures of mobility. Cross-sectional; secondary data analysis of a cohort study. Outpatient rehabilitation center. Community-dwelling adults aged ≥65 years with self-reported mobility limitations and symptomatic lumbar spinal stenosis (N=54). Not applicable. Short Physical Performance Battery score, habitual gait speed, and chair stand test. Symptomatic lumbar spinal stenosis was classified using self-reported symptoms of neurogenic claudication and imaging. Among 430 community-dwelling older adults, 54 (13%) met criteria for symptomatic lumbar spinal stenosis. Compared with participants without symptomatic lumbar spinal stenosis, those with symptomatic lumbar spinal stenosis had more comorbidities, higher body mass index, greater pain, and less balance confidence. Participants with symptomatic lumbar spinal stenosis had greater impairment in trunk extensor muscle endurance, leg strength, leg strength asymmetry, knee flexion range of motion (ROM), knee extension ROM, and ankle ROM compared with participants without symptomatic lumbar spinal stenosis. Five neuromuscular attributes were associated with performance-based mobility among participants with symptomatic lumbar spinal stenosis: trunk extensor muscle endurance, leg strength, leg strength asymmetry, knee flexion ROM, and knee extension ROM asymmetry. Community-dwelling older adults with self-reported mobility limitations and symptomatic lumbar spinal stenosis exhibit poorer health characteristics, greater neuromuscular impairment, and worse mobility when compared with those without symptomatic lumbar spinal stenosis. Poorer trunk extensor muscle endurance, leg strength, leg strength asymmetry, knee flexion ROM, and knee extension ROM asymmetry

Carbohydrate gel ingestion significantly improves the intermittent endurance capacity, but not sprint performance, of adolescent team games players during a simulated team games protocol.

Science.gov (United States)

Phillips, Shaun M; Turner, Anthony P; Sanderson, Mark F; Sproule, John

2012-03-01

The aim of this study was to investigate the influence of ingesting a carbohydrate (CHO) gel on the intermittent endurance capacity and sprint performance of adolescent team games players. Eleven participants [mean age 13.5 ± 0.7 years, height 1.72 ± 0.08 m, body mass (BM) 62.1 ± 9.4 kg] performed two trials separated by 3-7 days. In each trial, they completed four 15 min periods of part A of the Loughborough Intermittent Shuttle Test (LIST), followed by an intermittent run to exhaustion (part B). In the 5 min pre-exercise, participants consumed 0.818 mL kg(-1) BM of a CHO or a non-CHO placebo gel, and a further 0.327 mL kg(-1) BM every 15 min during part A of the LIST (38.0 ± 5.5 g CHO h(-1) in the CHO trial). Intermittent endurance capacity was increased by 21.1% during part B when the CHO gel was ingested (4.6 ± 2.0 vs. 3.8 ± 2.4 min, P games players during a simulated team games protocol.

Effects of a strength endurance training program on endurance levels Efectos de un programa de entrenamiento de la fuerza-resistencia sobre los niveles de resistencia

Directory of Open Access Journals (Sweden)

J. C. Redondo

2010-09-01

Full Text Available

The purpose of the current study was to determine whether a strength endurance training program of lower limbs isolate can increase endurance levels, both aerobic capacity and aerobic power, in order to adapt the strength training for endurance races. 20 phisically active men participated in the study. They were divided into two groups: control group (GC (n=10 and experimental group (GE (n=10. GE carried out a strength endurance training program for ten weeks. Results obtained showed that this type of training regime was useful to improve the performance in an aerobic endurance test. This could be due to an improvement in aerobic capacity, maximal dynamic strength, explosive strength and reactive strength. Moreover, there was a decrease in fat mass without increase in muscle mass.
Key Words:  Training, strength endurance, aerobic capacity, anthropometry.

El presente estudio pretende comprobar que el trabajo aislado de la fuerza resistencia en miembros inferiores produce una mejora de los niveles de resistencia, en términos tanto de potencia como de capacidad aeróbica, optimizando así el entrenamiento de la fuerza para pruebas de resistencia de media y larga duración. Para ello, veinte sujetos participaron en el estudio, dividiéndose de forma aleatoria en dos grupos: grupo control (GC (n=10 y grupo experimental (GE (n=10 el cual llevó a cabo un entrenamiento de fuerza resistencia extensivo por intervalos, de diez semanas de duración. Los resultados obtenidos muestran que este tipo de entrenamiento es efectivo para mejorar el rendimiento en una prueba de resistencia aeróbica para sujetos físicamente activos, gracias a la mejora de la capacidad aeróbica, de la fuerza máxima dinámica, elástico explosiva y elástico explosivo reactiva y a la disminución de los niveles de grasa

Impact of carbohydrate supplementation during endurance training on glycogen storage and performance

DEFF Research Database (Denmark)

Nybo, Lars; Pedersen, K.; Christensen, B.

2009-01-01

Abstract Aim: Glucose ingestion may improve exercise endurance, but it apparently also influences the transcription rate of several metabolic genes and it alters muscle metabolism during an acute exercise bout. Therefore, we investigated how chronic training responses are affected by glucose...... improvements in maximal oxygen uptake and peak power output during incremental cycling (both parameters elevated by 17% on average) and both groups lost approximately 3 kg of fat mass during the 8 weeks of training. An equal reduction in respiratory exchange ratio (0.02 units) during submaximal exercise.......05), while resting muscle glycogen increased (P influences various muscular training adaptations, but improvements...

Spin-trappers and vitamin E prolong endurance to muscle fatigue in mice

Energy Technology Data Exchange (ETDEWEB)

Novelli, G.P.; Bracciotti, G.; Falsini, S. (Univ. of Florence (Italy))

1990-01-01

The involvement of free radicals in endurance to muscle effort is suggested by experimental and clinical data. Therefore, experiments have been performed to observe the effect of trapping free radicals on endurance to swimming in mice. Animals were injected intraperitoneally with each of three spin-trappers (N-tert-Butyl-alpha-Phenyl-Nitrone (PBN),alpha-4-Pyridyil-1-Oxide-N-tert-Butyl-Nitrone (POBN) and 5,5-Dimethyl-1-Pirrolyn-N-Oxide (DMPO): 0.2 ml of 10(-1) molar solution). Each mouse was submitted to a swimming test to control resistance to exhaustion (a) without any treatment, (b) after administration of each spin-trapper in a random order (c) after saline. Control experiments were performed with saline and with vitamin E. Endurance to swimming was greatly prolonged by pretreatment with all the spin-trappers (DMPO less than 0.0001; POBN less than 0.0001; PBN less than 0.001) and with Vitamin E. Experiments state that compared to treatment with spin-trappers or Vitamin E, administration of saline alone did not enhance time to exhaustion so that the increase in time to exhaustion with the various free radical scavengers was not the effect of training. Therefore, free radicals could be considered as one of the factors terminating muscle effort in mice.

Somatic, Endurance Performance and Heart Rate Variability Profiles of Professional Soccer Players Grouped According to Age

Directory of Open Access Journals (Sweden)

Botek Michal

2016-12-01

Full Text Available This cross-sectional study compared somatic, endurance performance determinants and heart rate variability (HRV profiles of professional soccer players divided into different age groups: GI (17–19.9 years; n = 23, GII (20–24.9 years; n = 45, GIII (25–29.9 years; n = 30, and GIV (30–39 years; n = 26. Players underwent somatic and HRV assessment and maximal exercise testing. HRV was analyzed by spectral analysis of HRV, and high (HF and low (LF frequency power was transformed by a natural logarithm (Ln. Players in GIV (83 ± 7 kg were heavier (p 25 years showed negligible differences in Pmax unlike the age group differences demonstrated in VO2max. A shift towards relative sympathetic dominance, particularly due to reduced vagal activity, was apparent after approximately 8 years of competing at the professional level.

The Hypocretin/Orexin Antagonist Almorexant Promotes Sleep Without Impairment of Performance in Rats

Directory of Open Access Journals (Sweden)

Stephen R Morairty

2014-01-01

Full Text Available The hypocretin receptor (HcrtR antagonist almorexant (ALM has potent hypnotic actions but little is known about neurocognitive performance in the presence of ALM. HcrtR antagonists are hypothesized to induce sleep by disfacilitation of wake-promoting systems whereas GABAA receptor modulators such as zolpidem (ZOL induce sleep through general inhibition of neural activity. To test the hypothesis that less functional impairment results from HcrtR antagonist-induced sleep, we evaluated the performance of rats in the Morris Water Maze in the presence of ALM vs. ZOL. Performance in spatial reference memory (SRM and spatial working memory (SWM tasks were assessed during the dark period after equipotent sleep-promoting doses (100 mg/kg, po following undisturbed and sleep deprivation (SD conditions. ALM-treated rats were indistinguishable from vehicle (VEH-treated rats for all SRM performance measures (distance travelled, latency to enter, time within, and number of entries into, the target quadrant after both the undisturbed and 6 h SD conditions. In contrast, rats administered ZOL showed impairments in all parameters measured compared to VEH or ALM in the undisturbed conditions. Following SD, ZOL-treated rats also showed impairments in all measures. ALM-treated rats were similar to VEH-treated rats for all SWM measures (velocity, time to locate the platform and success rate at finding the platform within 60 s after both the undisturbed and SD conditions. In contrast, ZOL-treated rats showed impairments in velocity and in the time to locate the platform. Importantly, ZOL rats only completed the task 23-50% of the time while ALM and VEH rats completed the task 79-100% of the time. Thus, following equipotent sleep-promoting doses, ZOL impaired rats in both memory tasks while ALM rats performed at levels comparable to VEH rats. These results are consistent with the hypothesis that less impairment results from HcrtR antagonism than from GABAA

Mental skills comparison between elite sprint and endurance track and field runners according to their genetic polymorphism: a pilot study.

Science.gov (United States)

Znazen, Hela; Slimani, Maamer; Miarka, Bianca; Butovskaya, Marina; Siala, Hajer; Messaoud, Taieb; Chamari, Karim; Souissi, Nizar

2017-09-01

Achieving excellence in track and field athletes requires specific mental skills. The aim of the present study was to compare the mental skills between elite sprint and endurance athletes. Forty elite athletes (age 20.55±2.22 years, body mass 74.8±7.9 kg, height 1.70±0.1 m) participated in the present study. The athletes were classified into two groups according to their genetic polymorphism to physical activity: Endurance group (allele I, N.=20) and power group (allele D, N.=20). The mental skills were assessed by means of Ottawa Mental Skill Assessment Tool-3 inventory (OMSAT-3: based in foundation mental skills, psychosomatic skills, and cognitive skills subscales) before the competition period. Furthermore, genetic data were also collected. Sprint and endurance runners were participating in Tunisian National championship. The results showed a significant difference between elite sprint and endurance runners in the foundation mental and psychosomatic skills subscales (all, Pstudy revealed that goal setting, commitment, stress reactions, fear control, imagery, competition planning and mental practice were significantly higher among the elite sprint runners compared to the endurance runners (all, Pstudy could confirm the widely acclaimed research assumption that mental skills, such as goal setting, commitment and mental practice, are the predictor variables of power performances, while endurance performances are associated with different mental skills components. Finally, the results may inform applied practitioners regarding the differences in mental skill demands between power and endurance athletes and the genetic predisposition of practitioners.

Performance-based functional impairment and readmission and death: a prospective study.

Science.gov (United States)

Aubert, Carole E; Folly, Antoine; Mancinetti, Marco; Hayoz, Daniel; Donzé, Jacques D

2017-06-08

Readmission and death are frequent after a hospitalisation and difficult to predict. While many predictors have been identified, few studies have focused on functional status. We assessed whether performance-based functional impairment at discharge is associated with readmission and death after an acute medical hospitalisation. We prospectively included patients aged ≥50 years admitted to the Department of General Internal Medicine of a large community hospital. Functional status was assessed shortly before discharge using the Timed Up and Go test performed twice in a standard way by trained physiotherapists and was defined as a test duration ≥15 s. Sensitivity analyses using a cut-off at >10 and >20 s were performed. The primary and secondary outcome measures were unplanned readmission and death, respectively, within 6 months after discharge. Within 6 months after discharge, 107/338 (31.7%) patients had an unplanned readmission and 31/338 (9.2%) died. Functional impairment was associated with higher risk of death (OR 2.44, 95% CI 1.15 to 5.18), but not with unplanned readmission (OR 1.34, 95% CI 0.84 to 2.15). No significant association was found between functional impairment and the total number of unplanned readmissions (adjusted OR 1.59, 95% CI 0.95 to 2.67). Functional impairment at discharge of an acute medical hospitalisation was associated with higher risk of death, but not of unplanned readmission within 6 months after discharge. Simple performance-based assessment may represent a better prognostic measure for mortality than for readmission. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Endurance exercise training increases peripheral vascular response in human fingers.

Science.gov (United States)

Katayama, K; Shimoda, M; Maeda, J; Takemiya, T

1998-10-01

The purpose of this study was to clarify whether peripheral vascular response to alteration of transmural pressure is changed by endurance exercise training. The healthy male subjects (training group; n = 6) performed endurance exercise training that consisted of cycle ergometer exercise 5 d.week-1 and 30 min.d-1 for a period of 8 weeks. Changes in the peripheral vascular response to alteration of transmural pressure in the human finger were measured by a differential digital photoplethysmogram (DeltaDPG) and blood pressure during passive movement of the arm to different vertical hand positions relative to heart level. Following 8 weeks of endurance training, percent changes in DeltaDPG from heart level in the training group increased significantly (mean +/- SD, -48.1 +/- 7. 3 to -58.7 +/- 9.3% at the lowered position, 46.1 +/- 13.4 to 84.6 +/- 8.8% at the elevated position, ppressure, also significantly changed in the training group over the 8 weeks (5.6 +/- 1.3 to 2.7 +/- 1.6 mV. V-1.s-1.mmHg-1 at the lowered position, 30.0 +/- 12.4 to 54.4 +/- 18. 9 mV.V-1.s-1.mmHg-1 at the elevated position ). Maximal oxygen uptake (V.O2 max) was significantly increased in the training group. On the other hand, the control group (n = 6) showed no significant changes in all parameters for 8 weeks. Therefore these results suggest that endurance exercise training induces an increase in peripheral vascular response to alteration of transmural pressure in the human finger.

Category verbal fluency performance may be impaired in amnestic mild cognitive impairment

Directory of Open Access Journals (Sweden)

Márcio Luiz Figueredo Balthazar

Full Text Available Abstract To study category verbal fluency (VF for animals in patients with amnestic mild cognitive impairment (aMCI, mild Alzheimer disease (AD and normal controls. Method: Fifteen mild AD, 15 aMCI, and 15 normal control subjects were included. Diagnosis of AD was based on DSM-IV and NINCDS-ADRDA criteria, while aMCI was based on the criteria of the International Working Group on Mild Cognitive Impairment, using CDR 0.5 for aMCI and CDR 1 for mild AD. All subjects underwent testing of category VF for animals, lexical semantic function (Boston Naming-BNT, CAMCOG Similarities item, WAIS-R forward and backward digit span, Rey Auditory Verbal Learning (RAVLT, Mini-Mental Status Examination (MMSE, and other task relevant functions such as visual perception, attention, and mood state (with Cornell Scale for Depression in Dementia. Data analysis used ANOVA and a post-hoc Tukey test for intergroup comparisons, and Pearson's coefficient for correlations of memory and FV tests with other task relevant functions (statistical significance level was p<0.05. Results: aMCI patients had lower performance than controls on category VF for animals and on the backward digit span subtest of WAIS-R but higher scores compared with mild AD patients. Mild AD patients scored significantly worse than aMCI and controls across all tests. Conclusion: aMCI patients may have poor performance in some non-memory tests, specifically category VF for animals in our study, where this could be attributable to the influence of working memory.

Effect of antioxidant supplementation on insulin sensitivity in response to endurance exercise training

DEFF Research Database (Denmark)

Yfanti, Christina; Nielsen, Anders R; Åkerström, Thorbjörn

2011-01-01

While production of reactive oxygen and nitrogen species (RONS) is associated with some of the beneficial adaptations to regular physical exercise, it is not established whether RONS play a role in the improved insulin-stimulated glucose uptake in skeletal muscle obtained by endurance training....... To assess the effect of antioxidant supplementation during endurance training on insulin-stimulated glucose uptake, twenty-one young healthy (age 29±1 y; BMI 25±3 Kg m(-2)) men were randomly assigned into either an antioxidant (AO; 500 mg vitamin C and 400 IU vitamin E (a-tocopherol) daily) or a placebo (PL......) group that both underwent a supervised intense endurance-training program, 5 times per week for 12 weeks. A 3-hour euglycemic-hyperinsulinemic clamp, a maximal oxygen consumption (VO(2max)) and maximal power output (P(max)) test, and body composition measurements (fat mass, fat-free mass) were performed...

Survey of methods for the rating of psychiatric impairment in Australia.

Science.gov (United States)

Mendelson, George

2004-05-01

One of the enduring clinical issues in the assessment of plaintiffs in personal injury and workers' compensation claims, as well as applicants for social security and disablement benefits, is that of the evaluation of impairment and work incapacity. Many writers on this topic confuse the concepts of impairment and disability, and similar confusion is reflected in a number of the rating methods that purport to evaluate impairment but in reality assess disability. In Australia there are 20 distinct statutory schemes for workers' compensation, motor accident compensation, and social security and other benefits, which utilise a variety of methods for the rating of psychiatric impairment. Recent legislative changes designed to restrict access to personal injury compensation at common law, which in two Australian State jurisdictions require the use of impairment rating scales, also specify the rating methods to be used in the assessment of psychiatric impairment. This article discusses the concepts of impairment and disability as defined by the World Health Organisation, and reviews the various methods for the rating of psychiatric impairment that are specified by statute in the federal and State jurisdictions in Australia.

Maximal power output during incremental exercise by resistance and endurance trained athletes.

Science.gov (United States)

Sakthivelavan, D S; Sumathilatha, S

2010-01-01

This study was aimed at comparing the maximal power output by resistance trained and endurance trained athletes during incremental exercise. Thirty male athletes who received resistance training (Group I) and thirty male athletes of similar age group who received endurance training (Group II) for a period of more than 1 year were chosen for the study. Physical parameters were measured and exercise stress testing was done on a cycle ergometer with a portable gas analyzing system. The maximal progressive incremental cycle ergometer power output at peak exercise and carbon dioxide production at VO2max were measured. Highly significant (P biofeedback and perk up the athlete's performance.

Aerobic endurance in HIV-positive young adults and HIV-negative ...

African Journals Online (AJOL)

Background: Aerobic endurance is an important aspect of physical fitness that enables individuals living with HIV to endure in the work place as well as in agricultural operations in order to earn a living and improve their quality of life. However, despite high HIV prevalence rates, the aerobic endurance status of young ...

Effects of plyometric training on maximal-intensity exercise and endurance in male and female soccer players.

Science.gov (United States)

Ramírez-Campillo, Rodrigo; Vergara-Pedreros, Marcelo; Henríquez-Olguín, Carlos; Martínez-Salazar, Cristian; Alvarez, Cristian; Nakamura, Fábio Yuzo; De La Fuente, Carlos I; Caniuqueo, Alexis; Alonso-Martinez, Alicia M; Izquierdo, Mikel

2016-01-01

In a randomised controlled trial design, effects of 6 weeks of plyometric training on maximal-intensity exercise and endurance performance were compared in male and female soccer players. Young (age 21.1 ± 2.7 years) players with similar training load and competitive background were assigned to training (women, n = 19; men, n = 21) and control (women, n = 19; men, n = 21) groups. Players were evaluated for lower- and upper-body maximal-intensity exercise, 30 m sprint, change of direction speed and endurance performance before and after 6 weeks of training. After intervention, the control groups did not change, whereas both training groups improved jumps (effect size (ES) = 0.35-1.76), throwing (ES = 0.62-0.78), sprint (ES = 0.86-1.44), change of direction speed (ES = 0.46-0.85) and endurance performance (ES = 0.42-0.62). There were no differences in performance improvements between the plyometric training groups. Both plyometric groups improved more in all performance tests than the controls. The results suggest that adaptations to plyometric training do not differ between men and women.

Vitamin B1-deficient mice show impairment of hippocampus-dependent memory formation and loss of hippocampal neurons and dendritic spines: potential microendophenotypes of Wernicke-Korsakoff syndrome.

Science.gov (United States)

Inaba, Hiroyoshi; Kishimoto, Takuya; Oishi, Satoru; Nagata, Kan; Hasegawa, Shunsuke; Watanabe, Tamae; Kida, Satoshi

2016-12-01

Patients with severe Wernicke-Korsakoff syndrome (WKS) associated with vitamin B1 (thiamine) deficiency (TD) show enduring impairment of memory formation. The mechanisms of memory impairment induced by TD remain unknown. Here, we show that hippocampal degeneration is a potential microendophenotype (an endophenotype of brain disease at the cellular and synaptic levels) of WKS in pyrithiamine-induced thiamine deficiency (PTD) mice, a rodent model of WKS. PTD mice show deficits in the hippocampus-dependent memory formation, although they show normal hippocampus-independent memory. Similarly with WKS, impairments in memory formation did not recover even at 6 months after treatment with PTD. Importantly, PTD mice exhibit a decrease in neurons in the CA1, CA3, and dentate gyrus (DG) regions of the hippocampus and reduced density of wide dendritic spines in the DG. Our findings suggest that TD induces hippocampal degeneration, including the loss of neurons and spines, thereby leading to enduring impairment of hippocampus-dependent memory formation.

Vitamin B1-deficient mice show impairment of hippocampus-dependent memory formation and loss of hippocampal neurons and dendritic spines: potential microendophenotypes of Wernicke–Korsakoff syndrome

Science.gov (United States)

Inaba, Hiroyoshi; Kishimoto, Takuya; Oishi, Satoru; Nagata, Kan; Hasegawa, Shunsuke; Watanabe, Tamae; Kida, Satoshi

2016-01-01

Patients with severe Wernicke–Korsakoff syndrome (WKS) associated with vitamin B1 (thiamine) deficiency (TD) show enduring impairment of memory formation. The mechanisms of memory impairment induced by TD remain unknown. Here, we show that hippocampal degeneration is a potential microendophenotype (an endophenotype of brain disease at the cellular and synaptic levels) of WKS in pyrithiamine-induced thiamine deficiency (PTD) mice, a rodent model of WKS. PTD mice show deficits in the hippocampus-dependent memory formation, although they show normal hippocampus-independent memory. Similarly with WKS, impairments in memory formation did not recover even at 6 months after treatment with PTD. Importantly, PTD mice exhibit a decrease in neurons in the CA1, CA3, and dentate gyrus (DG) regions of the hippocampus and reduced density of wide dendritic spines in the DG. Our findings suggest that TD induces hippocampal degeneration, including the loss of neurons and spines, thereby leading to enduring impairment of hippocampus-dependent memory formation. PMID:27576603

Hypertension in master endurance athletes.

Science.gov (United States)

Hernelahti, M; Kujala, U M; Kaprio, J; Karjalainen, J; Sarna, S

1998-11-01

To determine whether long-term very vigorous endurance training prevents hypertension. Cohort study of master orienteering runners and controls. Finland. In 1995, a health questionnaire was completed by 264 male orienteering runners (response rate 90.4%) who had been top-ranked in competitions among men aged 35-59 years in 1984, and by 388 similarly aged male controls (response rate 87.1%) who were healthy at the age of 20 years and free of overt ischemic heart disease in 1985. Self-report of medication for hypertension. In the endurance athlete group, the crude prevalence (8.7%) of subjects who had used medication for hypertension was less than a third of that in the control group (27.8%). Even after adjusting for age and body mass index, the difference between the groups was still significant (odds ratio for athletes 0.43, 95% confidence interval 0.25-0.76). Long-term vigorous endurance training is associated with a low prevalence of hypertension. Some of the effect can be explained by a lower body mass, but exercise seems to induce a lower rate of hypertension by other mechanisms than by decreasing body weight

ANTHROPOLOGY DIMENSIONS AS INDEPENDENT AEROBIC ENDURANCE

Directory of Open Access Journals (Sweden)

Ratko Pavlović

2009-11-01

Full Text Available Endurance as human capability is treated in two ways. Some authors define it as mobility capability, while others deny this theory. The denying of this theory lies in attitude that endurance is saturated with psychological factors (motivation and cardio- vascular factors as well and is often identified with aero power, typical dimension of fun- ctional diagnostics. Having that in mind this research enabled the obtaining of necessary informations which could contribute to the clearing up of these uncoordinated opinions. The research included 110 student of the III year Phisical Education in East Sarajevo, male gender. Nine (9 predictors has been applied (4 variables for mobility space estima- te, 5 variables for morphology and functional space estimate and variable used for the estimate of endurance race 1500m. Obtained results confirmed statistical significance of two functional capability variable of Harvard step test, Margarija test and mobility variable race 4x15 meters with the race results.

Physical fitness differences of students with different cardiorespiratory endurance levels

Directory of Open Access Journals (Sweden)

Stojanović Darko

2016-01-01

Full Text Available In order to determine physical fitness differences in students with different cardiorespiratory endurance levels, a study was conducted on a sample of students of the Faculty of Sport and Physical Education at the University of Nis. The sample was divided into two subsamples, where the first subsample comprised 27 female students and the other 35 male students. Physical fitness was assessed using eight tests from the Eurofit battery of tests: the single-leg balance test - for the assessment of general balance, plate tapping - for the assessment of speed of movement, sit-and-reach - for the assessment of flexibility, the standing broad jump - for the assessment of explosive strength, the handgrip test - for the assessment of static strength, sit-ups - for the assessment of repetitive trunk strength, the bent arm hang - for the assessment of muscular endurance and the 10x5 meter shuttle run - for the assessment of the speed/agility. Cardiorespiratory endurance was estimated with the aid of 20 m endurance shuttle-run test. Based on the level of cardiorespiratory endurance, the participants in each subsample, were divided into three groups using a cluster analysis: high (VKRI, average (PKRI and low level (NKRI. The physical fitness differences of students with different cardiorespiratory endurance levels were calculated using the one-way analysis of variance. The results showed that there were no differences in physical fitness of students with different cardiorespiratory endurance levels. Based on the results it can be concluded that the level of cardiorespiratory endurance does not affect the components of physical fitness among students of both sexes.

Endurance- and Resistance-Trained Men Exhibit Lower Cardiovascular Responses to Psychosocial Stress Than Untrained Men.

Science.gov (United States)

Gröpel, Peter; Urner, Maren; Pruessner, Jens C; Quirin, Markus

2018-01-01

Evidence shows that regular physical exercise reduces physiological reactivity to psychosocial stress. However, previous research mainly focused on the effect of endurance exercise, with only a few studies looking at the effect of resistance exercise. The current study tested whether individuals who regularly participate in either endurance or resistance training differ from untrained individuals in adrenal and cardiovascular reactivity to psychosocial stress. Twelve endurance-trained men, 10 resistance-trained men, and 12 healthy but untrained men were exposed to a standardized psychosocial stressor, the Trier Social Stress Test. Measurements of heart rate, free salivary cortisol levels, and mood were obtained throughout the test and compared among the three groups. Overall, both endurance- and resistance-trained men had lower heart rate levels than untrained men, indicating higher cardiac performance of the trained groups. Trained men also exhibited lower heart rate responses to psychosocial stress compared with untrained men. There were no significant group differences in either cortisol responses or mood responses to the stressor. The heart rate results are consistent with previous studies indicating reduced cardiovascular reactivity to psychosocial stress in trained individuals. These findings suggest that long-term endurance and resistance trainings may be related to the same cardiovascular benefits, without exhibiting strong effects on the cortisol reactivity to stress.

Functional impairment in patients with major depressive disorder: the 2-year PERFORM study.

Science.gov (United States)

Hammer-Helmich, Lene; Haro, Josep Maria; Jönsson, Bengt; Tanguy Melac, Audrey; Di Nicola, Sylvie; Chollet, Julien; Milea, Dominique; Rive, Benoît; Saragoussi, Delphine

2018-01-01

The Prospective Epidemiological Research on Functioning Outcomes Related to Major depressive disorder (PERFORM) study describes the course of depressive symptoms, perceived cognitive symptoms, and functional impairment over 2 years in outpatients with major depressive disorder (MDD) and investigates the patient-related factors associated with functional impairment. This was a 2-year observational study in 1,159 outpatients with MDD aged 18-65 years who were either initiating antidepressant monotherapy or undergoing their first switch of antidepressant. Functional impairment was assessed by the Sheehan Disability Scale and the Work Productivity and Activity Impairment questionnaire. Patients assessed depression severity using the nine-item Patient Health Questionnaire and severity of perceived cognitive symptoms using the five-item Perceived Deficit Questionnaire. To investigate which patient-related factors were associated with functional impairment, univariate analyses of variance were performed to identify relevant factors that were then included in multivariate analyses of covariance at baseline, month 2, months 6 and 12 combined, and months 18 and 24 combined. The greatest improvement in depressive symptoms, perceived cognitive symptoms, and functional impairment was seen immediately (within 2 months) following initiation or switch of antidepressant therapy, followed by more gradual improvement and long-term stabilization. Improvement in perceived cognitive symptoms was less marked than improvement in depressive symptoms during the acute treatment phase. Functional impairment in patients with MDD was not only associated with severity of depressive symptoms but also independently associated with severity of perceived cognitive symptoms when adjusted for depression severity throughout the 2 years of follow-up. These findings highlight the burden of functional impairment in MDD and the importance of recognizing and managing cognitive symptoms in daily practice.

Determinants of gross motor skill performance in children with visual impairments.

Science.gov (United States)

Haibach, Pamela S; Wagner, Matthias O; Lieberman, Lauren J

2014-10-01

Children with visual impairments (CWVI) generally perform poorer in gross motor skills when compared with their sighted peers. This study examined the influence of age, sex, and severity of visual impairment upon locomotor and object control skills in CWVI. Participants included 100 CWVI from across the United States who completed the Test of Gross Motor Development II (TGMD-II). The TGMD-II consists of 12 gross motor skills including 6 object control skills (catching, kicking, striking, dribbling, throwing, and rolling) and 6 locomotor skills (running, sliding, galloping, leaping, jumping, and hopping). The full range of visual impairments according to United States Association for Blind Athletes (USABA; B3=20/200-20/599, legally blind; B2=20/600 and up, travel vision; B1=totally blind) were assessed. The B1 group performed significantly worse than the B2 (0.000 ≤ p ≤ 0.049) or B3 groups (0.000 ≤ p ≤ 0.005); however, there were no significant differences between B2 and B3 except for the run (p=0.006), catch (p=0.000), and throw (p=0.012). Age and sex did not play an important role in most of the skills, with the exception of boys outperforming girls striking (p=0.009), dribbling (p=0.013), and throwing (p=0.000), and older children outperforming younger children in dribbling (p=0.002). The significant impact of the severity of visual impairment is likely due to decreased experiences and opportunities for children with more severe visual impairments. In addition, it is likely that these reduced experiences explain the lack of age-related differences in the CWVI. The large disparities in performance between children who are blind and their partially sighted peers give direction for instruction and future research. In addition, there is a critical need for intentional and specific instruction on motor skills at a younger age to enable CWVI to develop their gross motor skills. Copyright © 2014 Elsevier Ltd. All rights reserved.

Impact of low vision rehabilitation on functional vision performance of children with visual impairment.

Science.gov (United States)

Ganesh, Suma; Sethi, Sumita; Srivastav, Sonia; Chaudhary, Amrita; Arora, Priyanka

2013-09-01

To evaluate the impact of low vision rehabilitation on functional vision of children with visual impairment. The LV Prasad-Functional Vision Questionnaire, designed specifically to measure functional performance of visually impaired children of developing countries, was used to assess the level of difficulty in performing various tasks pre and post visual rehabilitation in children with documented visual impairment. Chi-square test was used to assess the impact of rehabilitation intervention on functional vision performance; a P visual acuity prior to the introduction of low vision devices (LVDs) was 0.90 ± 0.05 for distance and for near it was 0.61 ± 0.05. After the intervention, the acuities improved significantly for distance (0.2 ± 0.27; P visual rehabilitation was especially found in those activities related to their studying lifestyle like copying from the blackboard (P visual rehabilitation, especially with those activities which are related to their academic output. It is important for these children to have an early visual rehabilitation to decrease the impairment associated with these decreased visual output and to enhance their learning abilities.

VO(2peak), myocardial hypertrophy, and myocardial blood flow in endurance-trained men.

Science.gov (United States)

Laaksonen, Marko S; Heinonen, Ilkka; Luotolahti, Matti; Knuuti, Juhani; Kalliokoski, Kari K

2014-08-01

Endurance training induces cardiovascular and metabolic adaptations, leading to enhanced endurance capacity and exercise performance. Previous human studies have shown contradictory results in functional myocardial vascular adaptations to exercise training, and we hypothesized that this may be related to different degrees of hypertrophy in the trained heart. We studied the interrelationships between peak aerobic power (V˙O2peak), myocardial blood flow (MBF) at rest and during adenosine-induced vasodilation, and parameters of myocardial hypertrophy in endurance-trained (ET, n = 31) and untrained (n = 17) subjects. MBF and myocardial hypertrophy were studied using positron emission tomography and echocardiography, respectively. Both V˙O2peak (P negatively with adenosine-stimulated MBF, but when LV mass was taken into account as a partial correlate, this correlation disappeared. The present results show that increased LV mass in ET subjects explains the reduced hyperemic myocardial perfusion in this subject population and suggests that excessive LV hypertrophy has negative effect on cardiac blood flow capacity.

Hand grip endurance test relates to clinical state and prognosis in COPD patients better than 6-minute walk test distance

Directory of Open Access Journals (Sweden)

Kovarik M

2017-12-01

Full Text Available Miroslav Kovarik,1,2 Vera Joskova,1,2 Anna Patkova,1,2 Vladimir Koblizek,3 Zdenek Zadak,2 Miloslav Hronek1,2 1Department of Biological and Medical Sciences, Faculty of Pharmacy in Hradec Kralove, Charles University, Hradec Kralove, Czech Republic; 2Department of Research and Development, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic; 3Department of Pulmonary Medicine, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic Purpose: Patients with COPD present peripheral muscle dysfunction and atrophy, expressed as muscle strength and endurance reduction. The goal of this study was direct dynamometric assessment of hand grip endurance and strength in relation to the stage of disease, multidimensional predictors of mortality, and 6-minute walk test (6MWT. To the best of our knowledge, there has been no previous study determining these parameters.Patients and methods: In this observational study, 58 consecutive outpatients with stable COPD and 25 volunteers without respiratory problems were compared. All COPD subjects underwent a comprehensive examination to determine COPD severity, prognostic scales, and 6MWT. Body composition, basic spirometric parameters, and hand grip strength and endurance were determined in all study participants.Results: Patients in the COPD group had a 15% decrease in maximum strength (P=0.012 and a 28% decrease in area under the force/time curve (AUC of the endurance test (P<0.001 compared to the control group. Dynamometric parameters were significantly negatively associated with the stage of disease and values of multivariable prediction indexes, and positively associated with the results of 6MWT. In most cases, closer associations were found with AUC than with 6MWT and in the gender-specific groups.Conclusion: Both hand grip strength and endurance are impaired in COPD patients in comparison with the control group. In particular, AUC could be considered as an attractive option not only to

Effects of Cycling Versus Running Training on Sprint and Endurance Capacity in Inline Speed Skating

Directory of Open Access Journals (Sweden)

Carolin Stangier, Thomas Abel, Julia Mierau, Wildor Hollmann, Heiko K. Strüder

2016-03-01

Full Text Available The purpose of this study was to compare the effects of running versus cycling training on sprint and endurance capacity in inline speed skating. Sixteen elite athletes (8 male, 8 female, 24 ± 8 yrs were randomly assigned into 2 training groups performing either 2 session per week of treadmill running or ergometer cycling in addition to 3 skating specific sessions (technique, plyometrics, parkour for 8 weeks. Training intensity was determined within non-specific (cycling or running and effects on specific endurance capacity within a specific incremental exercise test. Before and after the intervention all athletes performed a specific (300m and one non-specific (30s cycling or 200m running all-out sprint test according to the group affiliation. To determine the accumulation of blood lactate (BLa and glucose (BGL 20 μl arterialized blood was drawn at rest, as well as in 1 min intervals for 10 min after the sprint test. The sport-specific peak oxygen uptake (VO2 peak was significantly increased (+17%; p = 0.01 in both groups and highly correlated with the sprint performance (r = -0.71. BLa values decreased significantly (-18%, p = 0.02 after the specific sprint test from pre to post-testing without any group effect. However, BGL values only showed a significant decrease (-2%, p = 0.04 in the running group. The close relationship between aerobic capacity and sprint performance in inline speed skating highlights the positive effects of endurance training. Although both training programs were equally effective in improving endurance and sprint capacities, the metabolic results indicate a faster recovery after high intensity efforts for all athletes, as well as a higher reliance on the fat metabolism for athletes who trained in the running group.

Effects of acute supplementation of Panax ginseng on endurance running in a hot & humid environment

Science.gov (United States)

Ping, Fadzel Wong Chee; Keong, Chen Chee; Bandyopadhyay, Amit

2011-01-01

Background & objectives: Athletes in Malaysia need to perform in a hot and humid environment due to the climatic nature of the country. c0 hronic supplementation of Panax ginseng (PG) (a deciduous perennial plant belonging to the Araliaceae family) enhances physical performance. As the ergogenic effect of acute supplementation of PG on endurance performance has not been explored in the Malaysian population especially in a hot and humid condition this study was taken up. Methods: Nine heat adapted recreational runners (age : 25.4 ± 6.9 yr, body mass : 57.6 ± 8.4 kg; body height : 168.3 ± 7.6 cm) were recruited in this placebo-controlled double-blind randomized study. Subjects ingested 200 mg of PG one hour before the exercise test on treadmill at 70 per cent of their VO2max in a laboratory environment of 31 °C and 70 per cent relative humidity. They drank 3 ml/kg body weight of cool water every 20 min during the exercise to prevent adverse effects of dehydration. Blood samples were drawn every 20 min for the analysis of glucose, lactate, insulin and free fatty acids. Oxygen uptake was determined every 20 min while heart rate, body and skin temperatures, and ratings of perceived exertion (RPE) were recorded every 10 min during the trials. Results: Endurance running time to exhaustion did not differ between PG and placebo trials. Heart rate, skin temperature, core body temperature, oxygen uptake, RPE, plasma insulin, glucose, free fatty acid and lactate levels during the endurance exercise did not show any significant differences between the trials. Interpretation & conclusions: We conclude that acute supplementation of 200 mg of PG did not affect the endurance running performance of the heat-adapted male recreational runners in the heat. PMID:21321426

An investigation of ultramarathon-associated visual impairment.

Science.gov (United States)

Høeg, Tracy B; Corrigan, Genevieve K; Hoffman, Martin D

2015-06-01

The purpose of this study was to investigate the characteristics under which ultramarathon-associated visual impairment occurs and to seek to identify its physiological basis and risk factors. Through an online questionnaire, distributed worldwide, we obtained information from 173 self-identified ultramarathon runners who had experienced visual impairment during an ultramarathon. We attempted to characterize this vision impairment-its symptoms, duration, and the conditions under which it occurs. Select characteristics were compared with a reference group of 412 registrants of the 161-km Western States Endurance Run. Ultramarathon-associated visual impairment was typically characterized as painless clouding of vision that resolved either during (13.5%) or after racing within a median of 3.5 hours (range 0 to 48 hours) upon cessation of running. The mean (±SD) distance at which vision impairment occurred was 73±40 km, and the 161-km distance was the most frequent race distance (46.8%) in which visual impairment occurred. Visual impairment was often recurrent, with respondents reporting having it develop during a median of 2 races. Respondents with a history of refractive surgery had more episodes than those without such history (median 3.5 vs 2 episodes, P=.010). Compared with the reference group, runners with visual impairment were nearly twice as likely (23.7% vs 12.1%, Pvisual impairment typically presents as a painless clouding of vision that is self-limited but tends to recur in certain runners. Risk appears higher among those with a history of refractive surgery, which is relevant for ultramarathon runners who are considering, or who have a history of, refractive surgery. Published by Elsevier Inc.

Impaired insulin-induced site-specific phosphorylation of TBC1 domain family, member 4 (TBC1D4) in skeletal muscle of type 2 diabetes patients is restored by endurance exercise-training

DEFF Research Database (Denmark)

Vind, B. F.; Pehmøller, Christian; Treebak, Jonas Thue

2011-01-01

AIMS/HYPOTHESIS: Insulin-mediated glucose disposal rates (R (d)) are reduced in type 2 diabetic patients, a process in which intrinsic signalling defects are thought to be involved. Phosphorylation of TBC1 domain family, member 4 (TBC1D4) is at present the most distal insulin receptor signalling...... event linked to glucose transport. In this study, we examined insulin action on site-specific phosphorylation of TBC1D4 and the effect of exercise training on insulin action and signalling to TBC1D4 in skeletal muscle from type 2 diabetic patients. METHODS: During a 3 h euglycaemic-hyperinsulinaemic (80...... mU min(-1) m(-2)) clamp, we obtained M. vastus lateralis biopsies from 13 obese type 2 diabetic and 13 obese, non-diabetic control individuals before and after 10 weeks of endurance exercise-training. RESULTS: Before training, reductions in insulin-stimulated R (d), together with impaired insulin...

Endurance race equines performance fed diets with oil levels Desempenho de equinos submetidos a enduro alimentados com níveis de óleo de soja na dieta

Directory of Open Access Journals (Sweden)

José Correa de Lacerda Neto

2009-06-01

Full Text Available In order to study the endurance equine performance, experimental diets composed by five increasing soybean oil levels (control, 6, 12, 18, 24% of the concentrate were given. The following variables were analyzed: lactate concentration (LA, Glucose (GL, Cardiac frequency (FC and rectal temperature (TR. Twenty Arabian horses were used, 9.5 ±5.5 years old, weight 400 ± 30 kg, undergone to an 80 Km endurance race simulation in a treadmill. The endurance was divided in four rings (phases with 20 km each. There was no effect (p>0.05 of the oil addition but there was an effect (P<0.05 of distance on the LA, TR, GL variables. For the FC variable, we observed the effect (p<0.05 of the soybean addition and the distance. The soybean oil addition upper than 6% in the concentrate maintained lower the cardiac frequency, favoring the endurance horse performance. This lower cardiac frequency could suggest that animal lasted longer time in aerobic metabolism, situation that was confirmed by the non exponential increase in the lactate concentration and the increase in the glucose concentration. The oil favored the endurance horse performance.Com o objetivo de estudar o desempenho de cavalos de enduro, foram fornecidas dietas compostas por cinco níveis crescentes de óleo de soja (controle – sem adição de óleo, 6, 12, 18 e 24% do concentrado. As seguintes variáveis foram analisadas: concentração de lactato sangüíneo (LA, glicemia (GL, freqüência cardíaca (FC e temperatura retal (TR. Foram utilizados 20 eqüinos da raça Árabe, idades 9,5 ±5,5 anos, pesos de 400 ± 30 kg, submetidos à simulação de prova de enduro de 80 km em esteira rolante. O enduro foi dividido em quatro anéis (fases de 20 km cada. Não foi observado efeito (p>0,05 da adição de óleo de soja, porém observou-se efeito (p<0,05 da distância percorrida sobre as variáveis LA, TR e GL. Para a variável FC foi observado efeito (p<0,05 da distância percorrida bem como da adi

Morning anaerobic performance is not altered by vigilance impairment.

Directory of Open Access Journals (Sweden)

Romain Lericollais

Full Text Available The aim of this study was to determine the role played by vigilance on the anaerobic performance recorded during a Wingate test performed at the bathyphase (nadir of the circadian rhythmicity. Twenty active male participants performed a 60-s Wingate test at 6 a.m. during 3 test sessions in counter-balanced order the day after either (i a normal reference night, (ii a total sleep deprivation night, or (iii a total sleep deprivation night associated with an extended simulated driving task from 9 p.m. to 5 a.m. During this task, the number of inappropriate line crossings (ILCs was used to control and quantify the effective decrease in the level of vigilance. The main findings show that (i vigilance of each participant was significantly altered (i.e., a drastic and progressive increase in ILCs is shown during the 7.5 hours of driving by the sleep deprivation night associated with an extended driving task; (ii the subjective evaluation of vigilance performed by self-rated scale revealed an increased impairment of the vigilance level between the normal reference night, the total sleep deprivation night and the total sleep deprivation night associated with an extended driving task; and (iii the morning following this last condition, during the Wingate test, the recorded cycling biomechanical parameters (peak power, mean power and fatigue index values, power decrease, and cycling kinetic and kinematic patterns were not significantly different from the two other conditions. Consequently, these results show that anaerobic performances recorded during a Wingate test performed at the bathyphase of the circadian rhythmicity are not altered by a drastic impairment in vigilance. These findings seem to indicate that vigilance is probably not a factor that contributes to circadian variations in anaerobic performance.

Simulated astigmatism impairs academic-related performance in children.

Science.gov (United States)

Narayanasamy, Sumithira; Vincent, Stephen J; Sampson, Geoff P; Wood, Joanne M

2015-01-01

Astigmatism is an important refractive condition in children. However, the functional impact of uncorrected astigmatism in this population is not well established, particularly with regard to academic performance. This study investigated the impact of simulated bilateral astigmatism on academic-related tasks before and after sustained near work in children. Twenty visually normal children (mean age: 10.8 ± 0.7 years; six males and 14 females) completed a range of standardised academic-related tests with and without 1.50 D of simulated bilateral astigmatism (with both academic-related tests and the visual condition administered in a randomised order). The simulated astigmatism was induced using a positive cylindrical lens while maintaining a plano spherical equivalent. Performance was assessed before and after 20 min of sustained near work, during two separate testing sessions. Academic-related measures included a standardised reading test (the Neale Analysis of Reading Ability), visual information processing tests (Coding and Symbol Search subtests from the Wechsler Intelligence Scale for Children) and a reading-related eye movement test (the Developmental Eye Movement test). Each participant was systematically assigned either with-the-rule (WTR, axis 180°) or against-the-rule (ATR, axis 90°) simulated astigmatism to evaluate the influence of axis orientation on any decrements in performance. Reading, visual information processing and reading-related eye movement performance were all significantly impaired by both simulated bilateral astigmatism (p  0.05). Simulated astigmatism led to a reduction of between 5% and 12% in performance across the academic-related outcome measures, but there was no significant effect of the axis (WTR or ATR) of astigmatism (p > 0.05). Simulated bilateral astigmatism impaired children's performance on a range of academic-related outcome measures irrespective of the orientation of the astigmatism. These findings have

Peripheral fatigue limits endurance exercise via a sensory feedback-mediated reduction in spinal motoneuronal output.

Science.gov (United States)

Amann, Markus; Venturelli, Massimo; Ives, Stephen J; McDaniel, John; Layec, Gwenael; Rossman, Matthew J; Richardson, Russell S

2013-08-01

This study sought to determine whether afferent feedback associated with peripheral muscle fatigue inhibits central motor drive (CMD) and thereby limits endurance exercise performance. On two separate days, eight men performed constant-load, single-leg knee extensor exercise to exhaustion (85% of peak power) with each leg (Leg1 and Leg2). On another day, the performance test was repeated with one leg (Leg1) and consecutively (within 10 s) with the other/contralateral leg (Leg2-post). Exercise-induced quadriceps fatigue was assessed by reductions in potentiated quadriceps twitch-force from pre- to postexercise (ΔQtw,pot) in response to supramaximal magnetic femoral nerve stimulation. The output from spinal motoneurons, estimated from quadriceps electromyography (iEMG), was used to reflect changes in CMD. Rating of perceived exertion (RPE) was recorded during exercise. Time to exhaustion (∼9.3 min) and exercise-induced ΔQtw,pot (∼51%) were similar in Leg1 and Leg2 (P > 0.5). In the consecutive leg trial, endurance performance of the first leg was similar to that observed during the initial trial (∼9.3 min; P = 0.8); however, time to exhaustion of the consecutively exercising contralateral leg (Leg2-post) was shorter than the initial Leg2 trial (4.7 ± 0.6 vs. 9.2 ± 0.4 min; P fatigue and associated afferent feedback limits the development of peripheral fatigue and compromises endurance exercise performance by inhibiting CMD.

Peculiarities of endurance development for first year students

Directory of Open Access Journals (Sweden)

A.G. Pochernina

2014-06-01

Full Text Available Purpose: to determine the dynamics of the specific endurance first-year students in the classroom of physical education. Material : the study involved 20 students. Conducted educational testing: seed of lifting in supine position, hang on bent arms, jumping from sitting up with the stop, run 30m, bending and straightening the arms in emphasis lying, tilt forward from a sitting position, shuttle run, broad jump start. Results : found that the passage of the training module volleyball observed development of specific endurance and all motor abilities. Established that the manifestation and development of motor skills are interrelated. Since force is a functional foundation for the development of other skills, flexibility - the foundation of all mechanical movements. Without the development of strength, speed, coordination abilities impossible to develop endurance. Therefore, it is inappropriate and incorrect receipt of unidirectional only specific endurance (dynamic power and static, speed-power. Conclusions: indicated the need to achieve functional specialization of the body in the direction which is necessary for high-level manifestation of certain motor skills.

Energy requirements for racing endurance sled dogs*

OpenAIRE

Loftus, John P.; Yazwinski, Molly; Milizio, Justin G.; Wakshlag, Joseph J.

2014-01-01

Endurance sled dogs have unique dietary energy requirements. At present, there is disparity in the literature regarding energy expenditure and thus energy requirements of these dogs. We sought to further elucidate energy requirements for endurance sled dogs under field conditions. Three sled dog teams completing the 2011 Yukon Quest volunteered to provide diet history. Nutritional content was evaluated and a mock meal was analysed for each team. Race data were obtained from www.yukonquest.com...

Self-efficacy and enjoyment of middle school children performing the progressive aerobic cardiovascular endurance run (PACER).

Science.gov (United States)

Kane, Irene; Robertson, Robert J; Fertman, Carl I; Nagle, Elizabeth F; McConnaha, Wendell R; Rabin, Bruce S

2013-10-01

Self-efficacy and enjoyment were examined among 34 middle school children (M age = 12.5 yr.) performing the Progressive Aerobic Cardiovascular Endurance Run (PACER). Exercise self-efficacy (running) and physical activity enjoyment were measured after viewing a video illustrating the PACER, and subsequently following a PACER test. Significantly greater pre- than post-exercise self-efficacy was reported; enjoyment scores did not differ. Ratings of self-efficacy were higher before exercise than after, but enjoyment scores were not significantly different. A significant correlation was found between post-exercise self-efficacy and enjoyment, but not between pre-exercise self-efficacy and enjoyment. Although positive correlations were found between PACER laps and pre-/post-exercise self-efficacy, correlations with ratings of enjoyment were not significant. Exercise self-efficacy was associated with children's beliefs about the task-specific PACER aerobic exercise; however, exercise enjoyment was stable. Children's self-efficacy and enjoyment beliefs should be considered when developing interventional strategies to promote aerobic exercise participation.

Ingestion of carbohydrate or carbohydrate plus protein does not enhance performance during endurance exercise: a randomized cross-over placebo-controlled clinical trial.

Science.gov (United States)

Finger, Débora; Lanferdini, Fábio Juner; Farinha, Juliano Boufleur; Brusco, Clarissa Müller; Helal, Lucas; Boeno, Francesco Pinto; Cadore, Eduardo Lusa; Pinto, Ronei Silveira

2018-03-15

Protein (PRO) combined with a carbohydrate (CHO) beverage may have an ergogenic effect on endurance performance. However, evidence regarding its efficacy on similar conditions to athletes' race day is still lacking. To compare the effect of three different nutritional supplementation strategies on performance and muscle recovery in a duathlon protocol. , 13 male athletes (29.7 ± 7.7 years) participated in three simulated Olympic-distance duathlons under three different, randomly assigned, supplementation regimens: carbohydrate drink (CHO, 75 g); isocaloric CHO plus protein drink (CHO+PRO, 60.5 g CHO + 14.5 g PRO); and, placebo drink (PLA), offered during the cycling bout. Blood samples were collected before, immediately after and 24 h after each test for creatine kinase (CK) analysis. Isometric peak torque (PT) was measured before and 24 h after each condition. The primary outcome was the time to complete the last 5km running section (t5km) in a self-selected pace. Statistical differences were considered when p<0.05. There was no difference in t5km between CHO (1270.3 ± 130.5 s) vs. CHO+PRO (1267.2 ± 138.9 s) vs. PLA (1275.4 ± 120 s); p = 0.87; ES ≤ 0.1. Pre-post changes for PT and CK values did not show differences in any of three conditions (p = 0.24, ES ≤ 0.4, p = 0.32, 0.3-1.04). For endurance sports lasting up to 2 h, with a pre-meal containing 1.5 g/kg of CHO, CHO or CHO+PRO supplementation does not offer additional benefits when compared to a PLA in performance and muscle recovery.

Endurance capacity of mice selectively bred for high voluntary wheel running.

Science.gov (United States)

Meek, Thomas H; Lonquich, Brian P; Hannon, Robert M; Garland, Theodore

2009-09-15

Mice from four lines bred for high voluntary wheel activity run approximately 3-fold more revolutions per day and have elevated maximal oxygen consumption during forced treadmill exercise, as compared with four unselected control (C) lines. We hypothesized that these high runner (HR) lines would have greater treadmill endurance-running capacity. Ninety-six mice from generation 49 were familiarized with running on a motorized treadmill for 3 days. On days 4 and 5, mice were given an incremental speed test (starting at 20 m min(-1), increased 1.5 m min(-1) every 2 min) and endurance was measured as the total time or distance run to exhaustion. Blood samples were taken to measure glucose and lactate concentrations at rest during the photophase, during peak nightly wheel running, and immediately following the second endurance test. Individual differences in endurance time were highly repeatable between days (r=0.79), and mice tended to run longer on the second day (paired t-test, Pwheel running and treadmill endurance differed between the sexes, reinforcing previous studies that indicate sex-specific responses to selective breeding. HR mice appear to have a higher endurance capacity than reported in the literature for inbred strains of mice or transgenics intended to enhance endurance.

Effects of oral sodium supplementation on indices of thermoregulation in trained, endurance athletes.

Science.gov (United States)

Earhart, Elizabeth L; Weiss, Edward P; Rahman, Rabia; Kelly, Patrick V

2015-03-01

Guidelines recommend the consumption of sodium during exercise to replace losses in sweat; however, the effects of sodium on thermoregulation are less clear. To determine the effects of high-dose sodium supplementation on indices of thermoregulation and related outcomes, 11 endurance athletes participated in a double-blind, randomized-sequence, crossover study in which they underwent 2-hrs of endurance exercise at 60% heart rate reserve with 1800 mg of sodium supplementation (SS) during one trial and placebo (PL) during the other trial. A progressive intensity time-to-exhaustion test was performed after the 2-hr steady state exercise as an assessment of exercise performance. Sweat rate was calculated from changes in body weight, accounting for fluid intake and urinary losses. Ratings of perceived exertion (RPE) and heat stress were assessed using verbal numeric scales. Cardiovascular drift was determined from the rise in HR during the 2-hr steady state exercise test. Skin temperature was measured with an infrared thermometer. Dehydration occurred in both SS and PL trials, as evidenced by substantial weight loss (2.03 ± 0.43% and 2.27 ± 0.70%, respectively; p = 0.261 between trials). Sweat rate was 1015.53 ± 239.10 ml·hr(-1) during the SS trial and 1053.60±278.24 ml/hr during the PL trial, with no difference between trials (p = 0.459). Heat stress ratings indicated moderate heat stress ("warm/hot" ratings) but were not different between trials (p = 0.825). Time to exhaustion during the SS trial was 6.88 ± 3.88 minutes and during the PL trial averaged 6.96 ± 3.61 minutes, but did not differ between trials (p = 0.919). Cardiovascular drift, skin temperature, and RPE did not differ between trials (all p > 0.05). High-dose sodium supplementation does not appear to impact thermoregulation, cardiovascular drift, or physical performance in trained, endurance athletes. However, in light of the possibility that high sodium intakes might have other adverse effects

Influence of Endurance Training During Childhood on Total Hemoglobin Mass.

Science.gov (United States)

Prommer, Nicole; Wachsmuth, Nadine; Thieme, Ina; Wachsmuth, Christian; Mancera-Soto, Erica M; Hohmann, Andreas; Schmidt, Walter F J

2018-01-01

Elite endurance athletes are characterized by markedly increased hemoglobin mass (Hbmass). It has been hypothesized that this adaptation may occur as a response to training at a very young age. Therefore, the aim of this study was to monitor changes in Hbmass in children aged 8-14 years following systematic endurance training. In the first study, Hbmass, VO2max, and lean body mass (LBM) were measured in 17 endurance-trained children (13 boys and 4 girls; aged 9.7 ± 1.3 years; training history 1.5±1.8 years; training volume 3.5 ± 1.6 h) twice a year for up to 3.5 years. The same parameters were measured once in a control group of 18 age-matched untrained children. Hbmass and blood volume (BV) were measured using the optimized CO-rebreathing technique, VO2max by an incremental test on a treadmill, and LBM by skin-fold measurements. In the second pilot study, the same parameters were measured in 9 young soccer athletes (aged 7.8 ± 0.2 years), and results were assessed in relation to soccer performance 2.5 years later. The increase in mean Hbmass during the period of study was 50% which was closely related to changes in LBM ( r = 0.959). A significant impact of endurance training on Hbmass was observed in athletes exercising more than 4 h/week [+25.4 g compared to the group with low training volume (LBM (11.4 g·kg -1 LBM) and overlapped with the effects of age. A strong relationship was present between absolute Hbmass and VO2max ( r = 0.939), showing that an increase of 1 g hemoglobin increases VO2max by 3.6 ml·min -1 . Study 2 showed a positive correlation between Hbmass and soccer performance 2.5 years later at age 10.3 ± 0.3 years ( r = 0.627, p = 0.035). In conclusion, children with a weekly training volume of more than 4 h show a 7% higher Hbmass than untrained children. Although this training effect is significant and independent of changes in LBM, the major factor driving the increase in Hbmass is still LBM.

Increasing Optimism Protects Against Pain-Induced Impairment in Task-Shifting Performance.

Science.gov (United States)

Boselie, Jantine J L M; Vancleef, Linda M G; Peters, Madelon L

2017-04-01

Persistent pain can lead to difficulties in executive task performance. Three core executive functions that are often postulated are inhibition, updating, and shifting. Optimism, the tendency to expect that good things happen in the future, has been shown to protect against pain-induced performance deterioration in executive function updating. This study tested whether this protective effect of a temporary optimistic state by means of a writing and visualization exercise extended to executive function shifting. A 2 (optimism: optimism vs no optimism) × 2 (pain: pain vs no pain) mixed factorial design was conducted. Participants (N = 61) completed a shifting task once with and once without concurrent painful heat stimulation after an optimism or neutral manipulation. Results showed that shifting performance was impaired when experimental heat pain was applied during task execution, and that optimism counteracted pain-induced deterioration in task-shifting performance. Experimentally-induced heat pain impairs shifting task performance and manipulated optimism or induced optimism counteracted this pain-induced performance deterioration. Identifying psychological factors that may diminish the negative effect of persistent pain on the ability to function in daily life is imperative. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2014. Scientific Opinion on the substantiation of a health claim related to carbohydrate solutions and maintenance of physical performance during endurance exercise pursuant to Article 13(5) of Regulation (EC) No 1924/2006

DEFF Research Database (Denmark)

Tetens, Inge

Following an application from the British Specialist Nutrition Association Ltd, submitted for authorisation of a health claim pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of the United Kingdom, the EFSA Panel on Dietetic Products, Nutrition and Allergies...... (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to carbohydrate solutions and maintenance of physical performance during endurance exercise. The food, which is proposed by the applicant to be the subject of the health claim, is “carbohydrate solutions...... of physical performance during endurance exercise as compared to “water–electrolyte solutions” cannot be established on the basis of the information provided. Maintenance of physical performance during endurance exercise is a beneficial physiological effect. Three meta-analyses of human intervention studies...

The effect of endurance training on muscle strength in young, healthy men in relation to hormonal status.

Science.gov (United States)

Grandys, M; Majerczak, J; Duda, K; Zapart-Bukowska, J; Sztefko, K; Zoladz, J A

2008-12-01

The objective of this study was to establish the effect of moderate intensity endurance training on muscle strength in relation to hormonal changes in the body. Fifteen young, healthy men took part in 5 week endurance training performed on a cycloergometer. Before and after training program, exercise testing sessions were performed involving all participants. Training program significantly increased V(O2 max) (P<0.05) and time to fatigue at 50% of maximal voluntary isometric contraction (TTF 50% MVC), P<0.03, but it did not affect maximal voluntary isometric contraction (MVC). This was accompanied by an increase (P<0.001) in total plasma testosterone (T) and free testosterone (fT) concentrations, whereas a decrease in sex hormone-binding globulin (SHBG) (P<0.02), growth hormone (P<0.05), free triiodothyronine (P<0.001) and free thyroxine (P<0.02) concentrations was observed. No changes were found in plasma cortisol (C) and insulin-like growth factor-I (IGF-I) concentrations. Additionally, MVC was positively correlated to T/C, fT/C and IGF-I/C ratios after the training, whereas time to fatigue at 50% of MVC was closely positively correlated to the SHBG concentration, both before and after endurance training. We have concluded that moderate intensity endurance training resulting in a significant increase in V(O2 max), did not affect the MVC, but it significantly increased time to fatigue at 50% of MVC. This index of local muscular endurance was greater in subjects with higher concentration of SHBG, both before and after the training.

Bone health in endurance athletes: runners, cyclists, and swimmers.

Science.gov (United States)

Scofield, Kirk L; Hecht, Suzanne

2012-01-01

Weight-bearing exercise has been recognized widely to be beneficial for long-term bone health. However inherent differences in bone-loading characteristics and energy expenditure during participation in endurance sports place many endurance athletes at a relative disadvantage with regard to bone health compared with other athletes. Adolescents and adults who participate in endurance sports, such as running, and non-weight-bearing sports, such as biking and swimming, often have lower bone mineral density (BMD) than athletes participating in ball and power sports, and sometimes their BMD is lower than their inactive peers. Low BMD increases the risk of stress and fragility fractures, both while an athlete is actively competing and later in life. This article reviews the variable effects of distance running, cycling, swimming, and triathlons on bone health; the evaluation of stress and fragility fractures; and the diagnosis, management, and prevention of low BMD in endurance athletes.

INFLUENCE OF PHYSICAL TRAINING ON CARDIORESPIRATORY ENDURANCE IN PREADOLESCENT AGE

Directory of Open Access Journals (Sweden)

Marjan Marinkovic

2009-01-01

Full Text Available Cardiorespiratory or aerobic endurance is the ability of the whole body to sustain physical activity for an extended period of time, involving relatively large groups of muscles. The attitudes on the possible impact of training on cardiorespiratory endurance in preadolescents are contradictory. Our study enrolled 195 boys aged 11 to 12 years. Experimental group (n=92 consisted of the children who had been involved with planned and programmed water polo training for at least two years. Control group (n=103 consisted of schoolchildren who only had had regular physical education in schools. Our investigation protocol included standardized anthropometric measurements and tests, performed respecting the appropriate protocols. Statistical analysis of the results demonstrated that there were no significant differences in age and relative values of oxygen consumption (VO2peak. Body height and mass, as well as the skinfold thickness, were significantly higher in experimental group subjects. The values of absolute VO2peak, FVC and FEV1.0 were also significantly higher in the examinees involved with water polo training. These findings stress the importance of a systematic training process even in this early period of growth and development in order for the trainees to acquire important functional advantages. We believe that a properly planned and programmed physical training can significantly contribute to the development of cardiorespiratory endurance even as early as preadolescent age.

The Level of Vision Necessary for Competitive Performance in Rifle Shooting: Setting the Standards for Paralympic Shooting With Vision Impairment

Directory of Open Access Journals (Sweden)

Peter M Allen

2016-11-01

Full Text Available The aim of this study was to investigate the level of vision impairment that would reduce performance in shooting; to guide development of entry criteria to visually impaired (VI shooting. Nineteen international-level shooters without vision impairment took part in the study. Participants shot an air rifle, while standing, towards a regulation target placed at the end of a 10m shooting range. Cambridge simulation glasses were used to simulate six different levels of vision impairment. Visual acuity (VA and contrast sensitivity (CS were assessed along with shooting performance in each of seven conditions of simulated impairment and compared to that with habitual vision. Shooting performance was evaluated by calculating each individual’s average score in every level of simulated vision impairment and normalising this score by expressing it as a percentage of the baseline performance achieved with habitual vision. Receiver Operating Characteristic (ROC curves were constructed to evaluate the ability of different VA and CS cut-off criteria to appropriately classify these athletes as achieving ‘expected’ or ‘below expected’ shooting results based on their performance with different levels of VA and CS. Shooting performance remained relatively unaffected by mild decreases in VA and CS, but quickly deteriorated with more moderate losses. The ability of visual function measurements to classify shooting performance was good, with 78% of performances appropriately classified using a cut-off of 0.53 logMAR and 74% appropriately classified using a cut-off of 0.83 logCS. The current inclusion criteria for VI shooting (1.0 logMAR is conservative, maximising the chance of including only those with an impairment that does impact performance, but potentially excluding some who do have a genuine impairment in the sport. A lower level of impairment would include more athletes who do have a genuine impairment but would potentially include those who do not

Effects of Cycling Versus Running Training on Sprint and Endurance Capacity in Inline Speed Skating

Science.gov (United States)

Stangier, Carolin; Abel, Thomas; Mierau, Julia; Hollmann, Wildor; Strüder, Heiko K.

2016-01-01

The purpose of this study was to compare the effects of running versus cycling training on sprint and endurance capacity in inline speed skating. Sixteen elite athletes (8 male, 8 female, 24 ± 8 yrs) were randomly assigned into 2 training groups performing either 2 session per week of treadmill running or ergometer cycling in addition to 3 skating specific sessions (technique, plyometrics, parkour) for 8 weeks. Training intensity was determined within non-specific (cycling or running) and effects on specific endurance capacity within a specific incremental exercise test. Before and after the intervention all athletes performed a specific (300m) and one non-specific (30s cycling or 200m running) all-out sprint test according to the group affiliation. To determine the accumulation of blood lactate (BLa) and glucose (BGL) 20 μl arterialized blood was drawn at rest, as well as in 1 min intervals for 10 min after the sprint test. The sport-specific peak oxygen uptake (VO2 peak) was significantly increased (+17%; p = 0.01) in both groups and highly correlated with the sprint performance (r = -0.71). BLa values decreased significantly (-18%, p = 0.02) after the specific sprint test from pre to post-testing without any group effect. However, BGL values only showed a significant decrease (-2%, p = 0.04) in the running group. The close relationship between aerobic capacity and sprint performance in inline speed skating highlights the positive effects of endurance training. Although both training programs were equally effective in improving endurance and sprint capacities, the metabolic results indicate a faster recovery after high intensity efforts for all athletes, as well as a higher reliance on the fat metabolism for athletes who trained in the running group. Key points In addition to a highly developed aerobic performance inline speed skaters also require a highly trained anaerobic capacity to be effective in the sprint sections such as the mass start, tactical attacks

Reliability and Validity of Finger Strength and Endurance Measurements in Rock Climbing

Science.gov (United States)

Michailov, Michail Lubomirov; Baláš, Jirí; Tanev, Stoyan Kolev; Andonov, Hristo Stoyanov; Kodejška, Jan; Brown, Lee

2018-01-01

Purpose: An advanced system for the assessment of climbing-specific performance was developed and used to: (a) investigate the effect of arm fixation (AF) on construct validity evidence and reliability of climbing-specific finger-strength measurement; (b) assess reliability of finger-strength and endurance measurements; and (c) evaluate the…

Ultra-endurance sports have no negative impact on indices of arterial stiffness.

Science.gov (United States)

Radtke, Thomas; Schmidt-Trucksäss, Arno; Brugger, Nicolas; Schäfer, Daniela; Saner, Hugo; Wilhelm, Matthias

2014-01-01

Marathon running has been linked with higher arterial stiffness. Blood pressure is a major contributor to pulse wave velocity (PWV). We examined indices of arterial stiffness with a blood pressure-independent method in marathon runners and ultra-endurance athletes. Male normotensive amateur runners were allocated to three groups according to former participation in competitions: group I (recreational athletes), group II (marathon runners) and group III (ultra-endurance athletes). Indices of arterial stiffness were measured with a non-invasive device (VaSera VS-1500N, Fukuda Denshi, Japan) to determine the cardio-ankle vascular index (CAVI, primary endpoint) and brachial-ankle PWV (baPWV). Lifetime training hours were calculated. Cumulative competitions were expressed as marathon equivalents. Linear regression analysis was performed to determine predictors for CAVI and baPWV. Measurements of arterial stiffness were performed in 51 subjects (mean age 44.6 ± 1.2 years): group I (n = 16), group II (n = 19) and group III (n = 16). No between-group differences existed in age, anthropometric characteristics and resting BP. CAVI and baPWV were comparable between all groups (P = 0.604 and P = 0.947, respectively). In linear regression analysis, age was the only independent predictor for CAVI (R(2) = 0.239, β = 0.455, P = 0.001). Systolic BP was significantly associated with baPWV (R(2) = 0.225, β = 0.403, P = 0.004). In middle-aged normotensive athletes marathon running and ultra-endurance sports had no negative impact on arterial stiffness.

Specific descriptions of functional providing of the special endurance of boxers

Directory of Open Access Journals (Sweden)

S.B. Kiprich

2015-03-01

Full Text Available Purpose: to determine the specific characteristics of functional and metabolic support of special endurance of qualified boxers. Material: in research took part 16 boxers of high qualification at the age of 19-26 years. To estimate special endurance is used technique of detection the basic parameters of performance boxers "Spuderg-10." To estimate the response of cardiorespiratory system during the test "3x3" is used portable ergo-spirometry complex «Meta Max 3B» (Cortex, Germany. Results: It is shown that the range of individual distinctions of indexes of capacity and functional providing of the special endurance increased in every round under act of accumulation of fatigue. It is related to distinctions of kinetics of the cardiorespiratory system (by the increase of pulmonary ventilation in the first round, by the consumption of О 2 (by a capacity for the achievement of VO 2 max - in the second and by power of reaction of respiratory indemnification of metabolic acidosis - in the third. These distinctions are registered in default of reliable distinctions of quantitative descriptions of acidemic changes in an organism, increasing in the process of the test job processing. Conclusions: in different periods (rounds in boxers high grade found differences of manifestation and combinations of properties features of functional readiness.

Effects of plyometric training and creatine supplementation on maximal-intensity exercise and endurance in female soccer players.

Science.gov (United States)

Ramírez-Campillo, Rodrigo; González-Jurado, José Antonio; Martínez, Cristian; Nakamura, Fábio Yuzo; Peñailillo, Luis; Meylan, Cesar M P; Caniuqueo, Alexis; Cañas-Jamet, Rodrigo; Moran, Jason; Alonso-Martínez, Alicia M; Izquierdo, Mikel

2016-08-01

To investigate the effects of a six-week plyometric training and creatine supplementation intervention on maximal-intensity and endurance performance in female soccer players during in-season training. Randomized, double-blind, placebo-controlled trial. Young (age 22.9±2.5y) female players with similar training load and competitive background were assigned to a plyometric training group receiving placebo (PLACEBO, n=10), a plyometric training group receiving creatine supplementation (CREATINE, n=10) or a control group receiving placebo without following a plyometric program (CONTROL, n=10). Athletes were evaluated for jumping, maximal and repeated sprinting, endurance and change-of-direction speed performance before and after six weeks of training. After intervention the CONTROL group did not change, whereas both plyometric training groups improved jumps (ES=0.25-0.49), sprint (ES=0.35-0.41), repeated sprinting (ES=0.48-0.55), endurance (ES=0.32-0.34) and change-of-direction speed performance (ES=0.46-0.55). However, the CREATINE group improved more in the jumps and repeated sprinting performance tests than the CONTROL and the PLACEBO groups. Adaptations to plyometric training may be enhanced with creatine supplementation. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

DIFFERENT ENDURANCE CHARACTERISTICS OF FEMALE AND MALE GERMAN SOCCER PLAYERS

Directory of Open Access Journals (Sweden)

C. Baumgart

2014-08-01

Full Text Available The aims of the present study were to assess gender differences regarding lactate threshold and intermittent shuttle run performance in female and male soccer players as well as to investigate the relationships between both endurance characteristics in both genders. Fourteen female (1st division and thirteen male (4th division soccer players completed an incremental test (IT to determine running velocities at 2 and 4 mmol · l-1 blood lactate (v2 and v4 and maximum velocity (vmax as well as an interval shuttle run test (ISRT to determine running distance. Based on v2 and v4 and their percentages in relation to vmax, three intensity zones were calculated: a low lactate zone (v4. Female soccer players have a lower v4 (8.2%, vmax (11.3% and ISRT distance (31.6%. No gender difference was found in v2. In contrast to males, ISRT distance correlates with vmax as well as with v2 and v4 in female soccer players. The intensity zones v4 differ between genders. The present study revealed that gender differences increase when the running performance is intermittent including change of directions. In both genders, different relationships between lactate threshold and intermittent shuttle run performance exist. During incremental testing, the running performances of female and male players reflect different distributions of aerobic and anaerobic metabolic pathways. The revealed gender differences should be considered for soccer endurance training.

Endurance test of DUPIC irradiation test rig-003

Energy Technology Data Exchange (ETDEWEB)

Moon, J.S; Yang, M.S.; Lee, C.Y.; Ryu, J.S.; Jeon, H.G

2001-04-01

This report presents the pressure drop, vibration and endurance test results for DUPIC Irradiation Test Rig-003 which was design and fabricated by KAERI. From the pressure drop and vibration test results, it is verified that DUPIC Irradiation Test Rig-003 satisfied the limit conditions of HANARO. And, remarkable wear is not observed in DUPIC Irradiation Test Rig-003 during 40 endurance test days.

Endurance test for DUPIC capsule

International Nuclear Information System (INIS)

Chung, Heung June; Bae, K. K.; Lee, C. Y.; Park, J. M.; Ryu, J. S.

1999-07-01

This report presents the pressure drop, vibration and endurance test results for mini-plate fuel rig which were designed fabricately by KAERI. From the pressure drop test results, it is noted that the flow rate across the capsule corresponding to the pressure drop of 200 kPa is measured to be about 9.632 kg/sec. Vibration frequency for the capsule ranges from 14 to 18.5 Hz. RMS (Root Mean Square) displacement for the fuel rig is less than 14 μm, and the maximum displacement is less than 54 μm. Based on the endurance test results, the appreciable fretting wear for the DUPIC capsule was not detected. Oxidation on the support tube is observed, also tiny trace of wear between contact points observed. (author). 4 refs., 10 tabs., 45 figs

Skin autofluorescence is associated with arterial stiffness and insulin level in endurance runners and healthy controls - Effects of aging and endurance exercise.

Science.gov (United States)

Couppé, Christian; Dall, Christian Have; Svensson, Rene Brüggebusch; Olsen, Rasmus Huan; Karlsen, Anders; Praet, Stephan; Prescott, Eva; Magnusson, S Peter

2017-05-01

Life-long regular endurance exercise yields positive effects on cardiovascular and metabolic function, disease and mortality rate. Glycation may be a major mechanism behind age-related diseases. However, it remains unknown if skin autofluorescence (SAF), which reflects glycation, is related to arterial and metabolic function in life-long endurance runners and sedentary controls. Healthy elderly men: 15 life-long endurance runners (OT) (64±4years) and 12 old untrained (OU) (66±4years), and healthy young men; ten young athletes (YT) (26±4years) matched to OT for running distance, and 12 young untrained (YU) (24±3years) were recruited. Endothelial function (reactive hyperemia index, RHI) and arterial stiffness (augmentation index, AI@75 and AI) were measured by an operator-independent PAT 2000. SAF was non-invasively determined using an autofluorescence spectrometer. For AI@75 there was an effect of age (page correction (both r 2 =0.19, paging and pathology). Surprisingly, endurance running only had modest effects on cardiovascular function compared to lean healthy controls. Copyright © 2017 Elsevier Inc. All rights reserved.

Triacilglicerol intramuscular: um importante substrato energético para o exercício de endurance Triacilglicerol intramuscular: un importante substrato energético para el ejercicio de endurance Intramuscular triacylglycerol: an important energetic substrate for endurance exercise

Directory of Open Access Journals (Sweden)

Mônica Aparecida Belmonte

2005-04-01

Full Text Available Os ácidos graxos são uma importante fonte de energia para exercício de endurance. Os ácidos graxos plasmáticos encontram-se disponíveis para as fibras musculares sob a forma de ácidos graxos associados à albumina ou agregados à molécula de triacilglicerol (TAG encontrada nas lipoproteínas. Entretanto, além dessas fontes plasmáticas, a hidrólise do TAG encontrado no músculo também pode contribuir com a oferta de ácidos graxos durante o exercício de endurance. O objetivo do presente trabalho foi realizar uma extensa revisão da literatura sobre a importância do TAG intramuscular como substrato energético. A revisão da literatura sugere que a contribuição dos estoques endógenos de TAG durante a realização do exercício de endurance é bastante relevante. Além disso, pode-se concluir que uma adaptação induzida pelo treinamento de endurance é o aumento dos estoques intramusculares de TAG. Após o treinamento de endurance, também é observado aumento na capacidade de utilização desses estoques. Apesar de parecer importante, a contribuição do TAG intramuscular ainda é motivo de controvérsia na literatura. Essa discrepância de resultados está relacionada às metodologias empregadas para estimar a sua oxidação no exercício. A fim de esgotar este assunto de maneira apropriada, mais pesquisas, com novos métodos (ex.: utilização de isótopos, ressonância magnética nuclear e microscopia eletrônica, precisam ser conduzidas.Los ácidos grasos son una fuente importante de energía para el ejercicio de endurance. Los ácidos grasos plasmáticos se encuentran disponibles en las fibras musculares bajo la forma de ácido graso asociado a la albúmina o agregados a la molécula del triacilglicerol (TAG encontrados en las lipoproteínas. Sin embargo, además de estos fuentes plasmáticas, la hidrólisis de los TAG encontrados en el músculo pueden contribuir también con la oferta de ácidos grasos durante el ejercicio

Validity, Reliability, and Sensitivity of a Volleyball Intermittent Endurance Test.

Science.gov (United States)

Rodríguez-Marroyo, Jose A; Medina-Carrillo, Javier; García-López, Juan; Morante, Juan C; Villa, José G; Foster, Carl

2017-03-01

To analyze the concurrent and construct validity of a volleyball intermittent endurance test (VIET). The VIET's test-retest reliability and sensitivity to assess seasonal changes was also studied. During the preseason, 71 volleyball players of different competitive levels took part in this study. All performed the VIET and a graded treadmill test with gas-exchange measurement (GXT). Thirty-one of the players performed an additional VIET to analyze the test-retest reliability. To test the VIET's sensitivity, 28 players repeated the VIET and GXT at the end of their season. Significant (P volleyball players.

Performance Measurement and Accommodation: Students with Visual Impairments on Pennsylvania's Alternate Assessment

Science.gov (United States)

Zebehazy, Kim T.; Zigmond, Naomi; Zimmerman, George J.

2012-01-01

Introduction: This study investigated the use of accommodations and the performance of students with visual impairments and severe cognitive disabilities on the Pennsylvania Alternate System of Assessment (PASA)yCoan alternate performance-based assessment. Methods: Differences in test scores on the most basic level (level A) of the PASA of 286…

Pacing and Self-regulation: Important Skills for Talent Development in Endurance Sports.

Science.gov (United States)

Elferink-Gemser, Marije T; Hettinga, Florentina J

2017-07-01

Pacing has been characterized as a multifaceted goal-directed process of decision making in which athletes need to decide how and when to invest their energy during the race, a process essential for optimal performance. Both physiological and psychological characteristics associated with adequate pacing and performance are known to develop with age. Consequently, the multifaceted skill of pacing might be under construction throughout adolescence, as well. Therefore, the authors propose that the complex skill of pacing is a potential important performance characteristic for talented youth athletes that needs to be developed throughout adolescence. To explore whether pacing is a marker for talent and how talented athletes develop this skill in middle-distance and endurance sports, they aim to bring together literature on pacing and literature on talent development and self-regulation of learning. Subsequently, by applying the cyclical process of self-regulation to pacing, they propose a practical model for the development of performance in endurance sports in youth athletes. Not only is self-regulation essential throughout the process of reaching the long-term goal of athletic excellence, but it also seems crucial for the development of pacing skills within a race and the development of a refined performance template based on previous experiences. Coaches and trainers are advised to incorporate pacing as a performance characteristic in their talent-development programs by stimulating their athletes to reflect, plan, monitor, and evaluate their races on a regular basis to build performance templates and, as such, improve their performance.

Altitude training for elite endurance athletes: A review for the travel medicine practitioner.

Science.gov (United States)

Flaherty, Gerard; O'Connor, Rory; Johnston, Niall

2016-01-01

High altitude training is regarded as an integral component of modern athletic preparation, especially for endurance sports such as middle and long distance running. It has rapidly achieved popularity among elite endurance athletes and their coaches. Increased hypoxic stress at altitude facilitates key physiological adaptations within the athlete, which in turn may lead to improvements in sea-level athletic performance. Despite much research in this area to date, the exact mechanisms which underlie such improvements remain to be fully elucidated. This review describes the current understanding of physiological adaptation to high altitude training and its implications for athletic performance. It also discusses the rationale and main effects of different training models currently employed to maximise performance. Athletes who travel to altitude for training purposes are at risk of suffering the detrimental effects of altitude. Altitude illness, weight loss, immune suppression and sleep disturbance may serve to limit athletic performance. This review provides an overview of potential problems which an athlete may experience at altitude, and offers specific training recommendations so that these detrimental effects are minimised. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nutrition to Support Recovery from Endurance Exercise: Optimal Carbohydrate and Protein Replacement.

Science.gov (United States)

Moore, Daniel R

2015-01-01

Proper nutrition is vital to optimize recovery after endurance exercise. Dietary carbohydrate and protein provide the requisite substrates to enhance glycogen resynthesis and remodel skeletal muscle proteins, respectively, both of which would be important to rapidly restore muscle function and performance. With short recovery windows (optimal ingestion of both carbohydrate and protein.

Upper Body Muscular Endurance Among Children 2-5 Years.

Science.gov (United States)

Gabbard, Carl P.; And Others

The upper body muscular endurance of males and females 2-5 years of age was assessed, and relationships relative to sex, age, endurance and selected anthropometric measures were investigated. None of the relationships were found to be of practical predicative value; while upper body muscular strength increased with age, no significant differences…

Age and visual impairment decrease driving performance as measured on a closed-road circuit.

Science.gov (United States)

Wood, Joanne M

2002-01-01

In this study the effects of visual impairment and age on driving were investigated and related to visual function. Participants were 139 licensed drivers (young, middle-aged, and older participants with normal vision, and older participants with ocular disease). Driving performance was assessed during the daytime on a closed-road driving circuit. Visual performance was assessed using a vision testing battery. Age and visual impairment had a significant detrimental effect on recognition tasks (detection and recognition of signs and hazards), time to complete driving tasks (overall course time, reversing, and maneuvering), maneuvering ability, divided attention, and an overall driving performance index. All vision measures were significantly affected by group membership. A combination of motion sensitivity, useful field of view (UFOV), Pelli-Robson letter contrast sensitivity, and dynamic acuity could predict 50% of the variance in overall driving scores. These results indicate that older drivers with either normal vision or visual impairment had poorer driving performance compared with younger or middle-aged drivers with normal vision. The inclusion of tests such as motion sensitivity and the UFOV significantly improve the predictive power of vision tests for driving performance. Although such measures may not be practical for widespread screening, their application in selected cases should be considered.

[Supplementary device for a dynamometer to evaluate and register muscular endurance indices].

Science.gov (United States)

Timoshenko, D A; Bokser, O Ia

1986-01-01

In practice of psychophysiologic research muscular endurance index is used for estimation of CNS function. Muscular endurance index is defined as relative time needed for maintaining the preset muscular effort. The described device widens the possibilities of a digital dynamometer for automatic estimation and recording of muscular endurance index in real time.

The Enduring Value of the Physical Examination.

Science.gov (United States)

Zaman, Junaid A B

2018-05-01

This article focuses exclusively on physical examination (PE) in the context of clinical medicine, that is, the interaction between a health care provider and patient. In essence, there is not only benefit (value) to PE but also that it will last (endure) for some time. Both "enduring" and "value" are explored in more depth with respect to the future integration of PE into the clinical assessment of a patient and how its value extends well beyond current diagnostic/cost-based metrics. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

The Level of Vision Necessary for Competitive Performance in Rifle Shooting: Setting the Standards for Paralympic Shooting with Vision Impairment.

Science.gov (United States)

Allen, Peter M; Latham, Keziah; Mann, David L; Ravensbergen, Rianne H J C; Myint, Joy

2016-01-01

The aim of this study was to investigate the level of vision impairment (VI) that would reduce performance in shooting; to guide development of entry criteria to visually impaired (VI) shooting. Nineteen international-level shooters without VI took part in the study. Participants shot an air rifle, while standing, toward a regulation target placed at the end of a 10 m shooting range. Cambridge simulation glasses were used to simulate six different levels of VI. Visual acuity (VA) and contrast sensitivity (CS) were assessed along with shooting performance in each of seven conditions of simulated impairment and compared to that with habitual vision. Shooting performance was evaluated by calculating each individual's average score in every level of simulated VI and normalizing this score by expressing it as a percentage of the baseline performance achieved with habitual vision. Receiver Operating Characteristic curves were constructed to evaluate the ability of different VA and CS cut-off criteria to appropriately classify these athletes as achieving 'expected' or 'below expected' shooting results based on their performance with different levels of VA and CS. Shooting performance remained relatively unaffected by mild decreases in VA and CS, but quickly deteriorated with more moderate losses. The ability of visual function measurements to classify shooting performance was good, with 78% of performances appropriately classified using a cut-off of 0.53 logMAR and 74% appropriately classified using a cut-off of 0.83 logCS. The current inclusion criteria for VI shooting (1.0 logMAR) is conservative, maximizing the chance of including only those with an impairment that does impact performance, but potentially excluding some who do have a genuine impairment in the sport. A lower level of impairment would include more athletes who do have a genuine impairment but would potentially include those who do not actually have an impairment that impacts performance in the sport. An

76 FR 58565 - Proposed Information Collection (Operation Enduring Freedom/Operation Iraqi Freedom Seriously...

Science.gov (United States)

2011-09-21

... (Operation Enduring Freedom/ Operation Iraqi Freedom Seriously Injured/Ill Service Member Veteran Worksheet... solicits comments on information provided to Operation Enduring Freedom/Operation Iraqi Freedom veterans... information technology. Title: Operation Enduring Freedom/Operation Iraqi Freedom Seriously Injured/Ill...

Protective Effect of Curcumin Supplementation and Light Resistance Exercises on Superoxide Dismutase Enzyme Activity and Malondialdehyde Levels in a Severe Endurance Training Period in Male Wistar Rats

Directory of Open Access Journals (Sweden)

A Gorzi

2017-07-01

Background and aim: Extreme endurance exercises lead to oxidative stress in athletes. Therefore, the purpose of this study was to investigate the effect of curcumin supplement supplementation and light resistance training on the activity of SOD and MDA levels of male Wistar rats during a 8-week endurance training. Methods: In the present experimental study, 36 male Wistar rats were randomly assigned into one of six control groups, curcumin, endurance training, exercise, after one week of information (age 9 weeks and weight 255.62 ± 19.69 grams. Endurance + resistance, endurance training + curcumin and endurance training + curcumin + resistance. Incremental endurance training (8 weeks, 5 sessions per week was performed on a special treadmill. Speed ​​and running time in the last week reached 35 m / min and 70 minutes. Resistance training (8 weeks, 2 sessions per week was performed on vertical ladder by closing the rat's weight to the tail. Rats received supplemental curcumin by intraperitoneal injection (8 weeks, 3 sessions per week, 30 mg / kg body weight. SOD activity of the muscle was measured using ELISA kits and serum MDA levels using Tobartic acid (TBARS method. Data were analyzed using one-way ANOVA (ANOVA.   Results: The antioxidant enzyme activity of SOD in the endometrial muscle of endurance group (1.08 ± 0.222 μg / ml was significantly lower than control group (22.2 ± 0.481 kg (P = 0.043, and SOD activity in the endurance + resistance group (1.87 ± 0.172, p = 0.44, endurance + curcumin (2.24 ± 0.222; P = 0.039, and endurance + curcumin + resistance (0.202 ± 0.15, p = 0.029 was significantly higher than endurance group. The levels of malondialdehyde in the endurance group (4.27 ± 0.438 nmol / ml protein were significantly higher in comparison with the control group (3.42 ± 0.350 (0.331 and Also, serum MDA levels in endurance + resistance groups (± 3.03 ± 0.342, p = 0.003, endurance + curcumin (p = 0.001, p <0.001, and endurance + curcumin

HIV-associated cognitive performance and psychomotor impairment in a Thai cohort on long-term cART.

Science.gov (United States)

Do, Tanya C; Kerr, Stephen J; Avihingsanon, Anchalee; Suksawek, Saowaluk; Klungkang, Supalak; Channgam, Taweesak; Odermatt, Christoph C; Maek-A-Nantawat, Wirach; Ruxtungtham, Kiat; Ananworanich, Jintanat; Valcour, Victor; Reiss, Peter; Wit, Ferdinand W

2018-01-01

To assess cognitive performance and psychomotor impairment in an HIV-positive cohort, well-suppressed on combination antiretroviral therapy (cART), in an Asian resource-limited setting. Cross-sectional sociodemographic and cognitive data were collected in 329 HIV-positive and 510 HIV-negative participants. Cognitive performance was assessed using the International HIV Dementia Scale (IHDS), Montreal Cognitive Assessment (MoCA), WAIS-III Digit Symbol, Trail Making A, and Grooved Pegboard (both hands). Psychomotor test scores in the HIV-positive participants were converted to Z-scores using scores of the HIV-negative participants as normative data. Psychomotor impairment was defined as performance on two tests more than 1 standard deviation (SD) from controls or more than 2 SD on one test. Multivariate linear and logistic regression analyses were used to investigate associations between HIV and non-HIV-related covariates and poorer cognitive performance and psychomotor impairment. HIV-positive participants, mean age 45 (SD 7.69) years received cART for a median of 12.1 years (interquartile range [IQR] 9.1-14.4). Median CD4 cell count was 563 cells/mm 3 (IQR 435-725), and 92.77% had plasma HIV RNA performance (tests all P 90% on long-term cART, we found that inferior cognitive performance and psychomotor impairment were primarily associated with non-HIV-related factors.

Prevention of vision loss protects against age-related impairment in learning and memory performance in DBA/2J mice

Directory of Open Access Journals (Sweden)

Aimee eWong

2013-09-01

Full Text Available The DBA/2J mouse is a model of pigmentary glaucoma in humans as it shows age‐related increases in intraocular pressure, retinal ganglion cell death and visual impairment. Previously, we showed that visual ability declines from 9 ‐12 months of age and visual impairment is correlated with poor learning and memory performance in visuo‐spatial tasks but not in tasks that do not depend on visual cues. To test the sensory impairment hypothesis of aging, which postulates that sensory impaired individuals are disadvantaged in their performance on psychometric tests as a direct result of difficulties in sensory perception, we treated DBA/2J mice with a conventional glaucoma medication used in humans (Timoptic‐XE, 0.00, 0.25 or 0.50% daily from 9 weeks to 12 months of age to determine whether prevention of vision loss prevented the decline in visuo-spatial learning and memory performance. At all ages tested (3, 6, 9 and 12 months of age, mice treated with Timoptic-XE (0.25 and 0.50% maintained a high level of performance, while 12 month old control mice (0.00% exhibited impaired performance in visually‐dependent, but not non‐visual tasks. These results demonstrate that when sensory function is preserved, cognitive performance is normalized. Thus, as in many aging humans, DBA/2J mice show age-related decrements in performance on visually presented cognitive tests, not because of cognitive impairment but as a direct consequence of poor visual ability. Our results demonstrate that age-related impairment in performance in visuo-spatial tasks in DBA/2J mice can be prevented by the preservation of visual ability.

Prevention of vision loss protects against age-related impairment in learning and memory performance in DBA/2J mice.

Science.gov (United States)

Wong, Aimée A; Brown, Richard E

2013-01-01

The DBA/2J mouse is a model of pigmentary glaucoma in humans as it shows age-related increases in intraocular pressure (IOP), retinal ganglion cell death and visual impairment. Previously, we showed that visual ability declines from 9 to 12 months of age and visual impairment is correlated with poor learning and memory performance in visuo-spatial tasks but not in tasks that do not depend on visual cues. To test the "sensory impairment" hypothesis of aging, which postulates that sensory impaired individuals are disadvantaged in their performance on psychometric tests as a direct result of difficulties in sensory perception, we treated DBA/2J mice with a conventional glaucoma medication used in humans (Timoptic-XE, 0.00, 0.25, or 0.50%) daily from 9 weeks to 12 months of age to determine whether prevention of vision loss prevented the decline in visuo-spatial learning and memory performance. At all ages tested (3, 6, 9, and 12 months of age), mice treated with Timoptic-XE (0.25 and 0.50%) maintained a high level of performance, while 12 month old control mice (0.00%) exhibited impaired performance in visually-dependent, but not non-visual tasks. These results demonstrate that when sensory function is preserved, cognitive performance is normalized. Thus, as in many aging humans, DBA/2J mice show age-related decrements in performance on visually presented cognitive tests, not because of cognitive impairment but as a direct consequence of poor visual ability. Our results demonstrate that age-related impairment in performance in visuo-spatial tasks in DBA/2J mice can be prevented by the preservation of visual ability.

76 FR 72243 - Proposed Information Collection (Operation Enduring Freedom/Operation Iraqi Freedom Veterans...

Science.gov (United States)

2011-11-22

... (Operation Enduring Freedom/ Operation Iraqi Freedom Veterans Health Needs Assessment) Activity; Comment... Operation Enduring Freedom/ Operation Iraqi Freedom veterans and their families. DATES: Written comments and...: Operation Enduring Freedom/Operation Iraqi Freedom Veterans Health Needs Assessment, VA Form 10-21091. OMB...

REVERSIBLE IMPAIRMENT OF ASSETS AND THE IMPACT ON ECONOMIC PERFORMANCE

Directory of Open Access Journals (Sweden)

MIRON VASILE-CRISTIAN-IOACHIM

2015-03-01

Full Text Available Economic performance is an essential objective of economic entities activating in the energy sector. The profit and loss account provides relevant information for performance analyzes, but evaluating the factors which determined the modification of the financial result demands detailed analyzes based on specific techniques. This paper develops and implements an econometric model that analyses the relation between gross profit and the reversible impairment of assets. The results of the analysis have shown that, in the energy sector, there is a significant connection between those two variables.

Cantonese tone production performance of mainstream school children with hearing impairment.

Science.gov (United States)

Cheung, Karen K L; Lau, Ada H Y; Lam, Joffee H S; Lee, Kathy Y S

2014-12-01

This study investigated the Cantonese tone production ability of children with hearing impairment studying in mainstream schools. The participants were 87 Cantonese-speaking children with mild-to-profound degrees of hearing loss aged 5.92-13.58 in Hong Kong. Most of the children were fitted with hearing aids (n = 65); 17 of them had profound hearing impairment, one who had severe hearing loss had cochlear implantation, and four who had mild hearing loss were without any hearing device. The Hong Kong Cantonese Articulation Test was administered, and the tones produced were rated by two of the authors and a speech-language pathologist. Group effects of tones, hearing loss level, and also an interaction of the two were found to be significant. The children with profound hearing impairment performed significantly worse than most of the other children. Tone 1 was produced most accurately, whereas tone 6 productions were the poorest. No relationship was found between the number of years of mainstreaming and tone production ability. Tone production error pattern revealed that confusion patterns in tone perception coincided with those in production. Tones having a similar fundamental frequency (F0) at the onset also posed difficulty in tone production for children with hearing impairment.

PERFORMANCE OF HIGH SCHOOL FOOTBALL PLAYERS ON CLINICAL MEASURES OF DEEP CERVICAL FLEXOR ENDURANCE AND CERVICAL ACTIVE RANGE OF MOTION: IS HISTORY OF CONCUSSION A FACTOR?

Science.gov (United States)

Smith, Laura; Ruediger, Thomas; Alsalaheen, Bara; Bean, Ryan

2016-04-01

More than one million adolescent athletes participated in organized high school sanctioned football during the 2014-15 season. These athletes are at risk for sustaining concussion. Although cervical spine active range of motion (AROM) and deep neck flexor endurance may serve a preventative role in concussion, and widespread clinical use of measurements of these variables, reference values are not available for this population. Cost effective, clinically relevant methods for measuring neck endurance are also well established for adolescent athletes. The purpose of this study was to report reference values for deep cervical flexor endurance and cervical AROM in adolescent football players and examine whether differences in these measures exist in high school football players with and without a history of concussion. Concussion history, cervical AROM, and deep neck flexor endurance were measured in 122 high school football players. Reference values were calculated for AROM and endurance measures; association were examined between various descriptive variables and concussion. No statistically significant differences were found between athletes with a history of concussion and those without. A modest inverse correlation was seen between body mass and AROM in the sagittal and transverse planes. The results of this study indicate that the participants with larger body mass had less cervical AROM in some directions. While cervical AROM and endurance measurements may not be adequate to identify adolescents with a history of previous concussions among high school football players. However, if a concussion is sustained, these measures can offer a baseline to examine whether cervical AROM is affected as compared to healthy adolescents. 2c.

Are There Deleterious Cardiac Effects of Acute and Chronic Endurance Exercise?

Science.gov (United States)

Eijsvogels, Thijs M. H.; Fernandez, Antonio B.; Thompson, Paul D.

2015-01-01

Multiple epidemiological studies document that habitual physical activity reduces the risk of atherosclerotic cardiovascular disease (ASCVD), and most demonstrate progressively lower rates of ASCVD with progressively more physical activity. Few studies have included individuals performing high-intensity, lifelong endurance exercise, however, and recent reports suggest that prodigious amounts of exercise may increase markers for, and even the incidence of, cardiovascular disease. This review examines the evidence that extremes of endurance exercise may increase cardiovascular disease risk by reviewing the causes and incidence of exercise-related cardiac events, and the acute effects of exercise on cardiovascular function, the effect of exercise on cardiac biomarkers, including “myocardial” creatine kinase, cardiac troponins, and cardiac natriuretic peptides. This review also examines the effect of exercise on coronary atherosclerosis and calcification, the frequency of atrial fibrillation in aging athletes, and the possibility that exercise may be deleterious in individuals genetically predisposed to such cardiac abnormalities as long QT syndrome, right ventricular cardiomyopathy, and hypertrophic cardiomyopathy. This review is to our knowledge unique because it addresses all known potentially adverse cardiovascular effects of endurance exercise. The best evidence remains that physical activity and exercise training benefit the population, but it is possible that prolonged exercise and exercise training can adversely affect cardiac function in some individuals. This hypothesis warrants further examination. PMID:26607287

Tenomodulin is Required for Tendon Endurance Running and Collagen I Fibril Adaptation to Mechanical Load

Directory of Open Access Journals (Sweden)

Sarah Dex

2017-06-01

Full Text Available Tendons are dense connective tissues that attach muscles to bone with an indispensable role in locomotion because of their intrinsic properties of storing and releasing muscle- generated elastic energy. Tenomodulin (Tnmd is a well-accepted gene marker for the mature tendon/ligament lineage and its loss-of -function in mice leads to a phenotype with distinct signs of premature aging on tissue and stem/progenitor cell levels. Based on these findings, we hypothesized that Tnmd might be an important factor in the functional performance of tendons. Firstly, we revealed that Tnmd is a mechanosensitive gene and that the C-terminus of the protein co-localize with collagen I-type fibers in the extracellular matrix. Secondly, using an endurance training protocol, we compared Tnmd knockout mice with wild types and showed that Tnmd deficiency leads to significantly inferior running performance that further worsens with training. In these mice, endurance running was hindered due to abnormal response of collagen I cross-linking and proteoglycan genes leading to an inadequate collagen I fiber thickness and elasticity. In sum, our study demonstrates that Tnmd is required for proper tendon tissue adaptation to endurance running and aids in better understanding of the structural-functional relationships of tendon tissues.

Ball-Sport Endurance and Sprint Test (BEAST90): validity and reliability of a 90-minute soccer performance test.

Science.gov (United States)

Williams, Jeremy D; Abt, Grant; Kilding, Andrew E

2010-12-01

The aim of this study was to determine the validity and reliability of a 90-minute soccer performance test: Ball-sport Endurance and Sprint Test (BEAST90). Fifteen healthy male amateur soccer players participated and attended 5 testing sessions over a 10-day period to perform physiologic and soccer-specific assessments. This included familiarization sessions and 2 full trials of the BEAST90, separated by 7 days. The total 90-minute distance, mean percent peak heart rate (HRpeak), and estimated percent peak oxygen uptake of the BEAST90 were 8,097 ± 458 m, 85 ± 5% and 82 ± 14%, respectively. Measures obtained from trial 1 and trial 2 were not significantly different (p > 0.05). Reliability of measures over 90 minutes ranged from 0.9-25.5% (% typical error). The BEAST90 protocol replicated soccer match play in terms of time, movement patterns, physical demands (volume and intensity), distances, and mean and HRpeak values, as well as having an aerobic load similar to that observed during a soccer match. Reproducibility of key physical measures during the BEAST90 were mostly high, suggesting good reliability. The BEAST90 could be used in studies that wish to determine the effects of training or nutritional interventions on prolonged intermittent physical performance.

Impaired exercise performance and skeletal muscle mitochondrial function in rats with secondary carnitine deficiency

Directory of Open Access Journals (Sweden)

Jamal BOUITBIR

2016-08-01

Full Text Available Purpose: The effects of carnitine depletion upon exercise performance and skeletal muscle mitochondrial function remain largely unexplored. We therefore investigated the effect of N-trimethyl-hydrazine-3-propionate (THP, a carnitine analogue inhibiting carnitine biosynthesis and renal carnitine reabsorption, on physical performance and skeletal muscle mitochondrial function in rats.Methods: Male Sprague Dawley rats were treated daily with water (control rats; n=12 or with 20 mg/100 g body weight THP (n=12 via oral gavage for 3 weeks. Following treatment, half of the animals of each group performed an exercise test until exhaustion.Results: Distance covered and exercise performance were lower in THP-treated compared to control rats. In the oxidative soleus muscle, carnitine depletion caused atrophy (-24% and impaired function of complex II and IV of the mitochondrial electron transport chain. The free radical leak (ROS production relative to oxygen consumption was increased and the cellular glutathione pool decreased. Moreover, mRNA expression of markers of mitochondrial biogenesis and mitochondrial DNA were decreased in THP-treated compared to control rats. In comparison, in the glycolytic gastrocnemius muscle, carnitine depletion was associated with impaired function of complex IV and increased free radical leak, whilst muscle weight and cellular glutathione pool were maintained. Markers of mitochondrial proliferation and mitochondrial DNA were unaffected.Conclusions: Carnitine deficiency is associated with impaired exercise capacity in rats treated with THP. THP-induced carnitine deficiency is associated with impaired function of the electron transport chain in oxidative and glycolytic muscle as well as with atrophy and decreased mitochondrial DNA in oxidative muscle.

Restorative effect of endurance exercise on behavioral deficits in the chronic mouse model of Parkinson's disease with severe neurodegeneration.

Science.gov (United States)

Pothakos, Konstantinos; Kurz, Max J; Lau, Yuen-Sum

2009-01-20

Animal models of Parkinson's disease have been widely used for investigating the mechanisms of neurodegenerative process and for discovering alternative strategies for treating the disease. Following 10 injections with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 25 mg/kg) and probenecid (250 mg/kg) over 5 weeks in mice, we have established and characterized a chronic mouse model of Parkinson's disease (MPD), which displays severe long-term neurological and pathological defects resembling that of the human Parkinson's disease in the advanced stage. The behavioral manifestations in this chronic mouse model of Parkinson's syndrome remain uninvestigated. The health benefit of exercise in aging and in neurodegenerative disorders including the Parkinson's disease has been implicated; however, clinical and laboratory studies in this area are limited. In this research with the chronic MPD, we first conducted a series of behavioral tests and then investigated the impact of endurance exercise on the identified Parkinsonian behavioral deficits. We report here that the severe chronic MPD mice showed significant deficits in their gait pattern consistency and in learning the cued version of the Morris water maze. Their performances on the challenging beam and walking grid were considerably attenuated suggesting the lack of balance and motor coordination. Furthermore, their spontaneous and amphetamine-stimulated locomotor activities in the open field were significantly suppressed. The behavioral deficits in the chronic MPD lasted for at least 8 weeks after MPTP/probenecid treatment. When the chronic MPD mice were exercise-trained on a motorized treadmill 1 week before, 5 weeks during, and 8-12 weeks after MPTP/probenecid treatment, the behavioral deficits in gait pattern, spontaneous ambulatory movement, and balance performance were reversed; whereas neuronal loss and impairment in cognitive skill, motor coordination, and amphetamine-stimulated locomotor activity were not

Specific characteristics of physical fitness at work anaerobic endurance type of rowers in canoe

Directory of Open Access Journals (Sweden)

Penchen Guo

2014-12-01

Full Text Available Purpose: to determine the effect of the reactive properties cardiorespiratory system to a special performance by canoe paddlers who specialize in the 200 m. Material : The study involved 22 paddler aged 18 - 29 years. Results : there were significant indicators of the reaction due to pulmonary performance and efficiency of anaerobic metabolism. The range of correlation coefficients (r was -0.54 - 0.77 (T 50 V E and 0,55-0,71 (V E. Conclusions : It was found that the optimization of the reactive properties of the cardiorespiratory system to realize the potential impact endurance rowers when using anaerobic nature. The greatest number of significant connections were indicators of efficiency and response of pulmonary ventilation. This allowed the evaluation of the functional improve information security work and increase specialized training sessions focus in the development of anaerobic endurance while working character in canoeing.

76 FR 73022 - Agency Information Collection (Operation Enduring Freedom/Operation Iraqi Freedom Seriously...

Science.gov (United States)

2011-11-28

... (Operation Enduring Freedom/ Operation Iraqi Freedom Seriously Injured/Ill Service Member Veteran Worksheet... No. 2900-0720.'' SUPPLEMENTARY INFORMATION: Title: Operation Enduring Freedom/Operation Iraqi Freedom... used VA Form 21-0773 as a checklist to ensure they provided Operation Enduring Freedom or Operation...

Effects of Low Versus Moderate Glycemic Index Diets on Aerobic Capacity in Endurance Runners: Three-Week Randomized Controlled Crossover Trial

Directory of Open Access Journals (Sweden)

Krzysztof Durkalec-Michalski

2018-03-01

Full Text Available The glycemic index (GI of ingested carbohydrates may influence substrate oxidation during exercise and athletic performance. Therefore, the aim of this study was to assess the effect of low- and moderate-GI three-week diets on aerobic capacity and endurance performance in runners. We conducted a randomized crossover feeding study of matched diets differing only in GI (low vs. moderate in 21 endurance-trained runners. Each participant consumed both, low- (LGI and moderate-GI (MGI high-carbohydrate (~60% and nutrient-balanced diets for three weeks each. At the beginning and end of each diet, participants had their aerobic capacity and body composition measured and performed a 12-min running test. After LGI, time to exhaustion during incremental cycling test (ICT and distance covered in the 12-min run were significantly increased. The MGI diet led to an increase in maximal oxygen uptake ( V ˙ O2max, but no performance benefits were found after the MGI diet. The LGI and MGI diets improved time and workload at gas exchange threshold (GET during ICT. The results indicate that a three-week high-carbohydrate LGI diet resulted in a small but significant improvement in athletic performance in endurance runners. Observed increase in V ˙ O2max on MGI diet did not affect performance.

Efficacy of Ashwagandha (Withania somnifera [L.] Dunal) in improving cardiorespiratory endurance in healthy athletic adults.

Science.gov (United States)

Choudhary, Bakhtiar; Shetty, A; Langade, Deepak G

2015-01-01

Ashwagandha (Withania somnifera [L.] Dunal) has been traditionally used for various actions ranging from vitalizer, improve endurance and stamina, promote longevity, improve immunity, and male and female fertility. However, clinical studies are needed to prove the clinical efficacy of this herb, especially in cardiovascular endurance and physical performance. This prospective, double-blind, randomized, and placebo-controlled study evaluated the efficacy of Ashwagandha roots extract in enhancing cardiorespiratory endurance and improving the quality of life (QOL) in 50 healthy male/female athletic adults. Cardiorespiratory endurance was assessed by measuring the oxygen consumption at peak physical exertion (VO2 max) levels during a 20 m shuttle run test. The World Health Organization self-reported QOL questionnaire (physical health, psychological health, social relationships, and environmental factors) was used to assess the QOL. Student's t-test was used to compare the differences in a mean and change from baseline VO2 max levels, whereas Wilcoxon signed-rank test was used to assess changes in QOL scores from baseline in the two groups. There was a greater increase from baseline (P < 0.0001) in the mean VO2 max with KSM-66 Ashwagandha (n = 24) compared to placebo (n = 25) at 8 weeks (4.91 and 1.42, respectively) and at 12 weeks (5.67 and 1.86 respectively). The QOL scores for all subdomains significantly improved to a greater extent in the Ashwagandha group at 12 weeks compared to placebo (P < 0.05). The findings suggest that Ashwagandha root extract enhances the cardiorespiratory endurance and improves QOL in healthy athletic adults.

Baroreflex buffering in sedentary and endurance exercise-trained healthy men.

Science.gov (United States)

Christou, Demetra D; Jones, Pamela Parker; Seals, Douglas R

2003-06-01

Baroreflex buffering plays an important role in arterial blood pressure control. Previous reports suggest that baroreflex sensitivity may be altered in endurance exercise-trained compared with untrained subjects. It is unknown, however, if in vivo baroreflex buffering is altered in the endurance exercise-trained state in humans. Baroreflex buffering was determined in 36 healthy normotensive men (18 endurance exercise-trained, 41+/-5 [SEM] years; 18 untrained, 41+/-4 years) by measuring the potentiation of the systolic blood pressure responses to a phenylephrine bolus and to incremental phenylephrine infusion during compared with before ganglionic blockade with trimethaphan. The exercise-trained men had a lower resting heart rate and higher maximal oxygen consumption and heart rate variability than the sedentary control subjects (all P=0.01). Mean levels and variability of blood pressure, cardiovagal baroreflex sensitivity (change in heart rate/change in systolic blood pressure), and basal muscle sympathetic nerve activity were not different in the two groups. The systolic blood pressure responses to phenylephrine were not different in the endurance-trained and untrained men before or during ganglionic blockade (P>0.6). Measures of baroreflex buffering with the use of a phenylephrine bolus (3.9+/-0.8 versus 4.0+/-0.7, trained versus untrained, P=0.85) and incremental infusion (2.8+/-0.4 versus 2.5+/-0.6, P=0.67) were similar in the two groups. Baroreflex buffering does not differ in endurance exercise-trained compared with untrained healthy men. These results support the concept that habitual vigorous endurance exercise does not modulate in vivo baroreflex buffering in healthy humans.

Digital Physical Activity Data Collection and Use by Endurance Runners and Distance Cyclists

Science.gov (United States)

Lee, Victor R.; Drake, Joel

2013-01-01

The introduction of sensor technologies to sports has allowed athletes to quantify and track their performance, adding an information-based layer to athletic practices. This information layer is particularly prevalent in practices involving formal competition and high levels of physical endurance, such as biking and running. We interviewed 20…

Endurance Factors Improve Hippocampal Neurogenesis and Spatial Memory in Mice

Science.gov (United States)

Kobilo, Tali; Yuan, Chunyan; van Praag, Henriette

2011-01-01

Physical activity improves learning and hippocampal neurogenesis. It is unknown whether compounds that increase endurance in muscle also enhance cognition. We investigated the effects of endurance factors, peroxisome proliferator-activated receptor [delta] agonist GW501516 and AICAR, activator of AMP-activated protein kinase on memory and…

Effects of a 12-Week Hatha Yoga Intervention on Cardiorespiratory Endurance, Muscular Strength and Endurance, and Flexibility in Hong Kong Chinese Adults: A Controlled Clinical Trial

Directory of Open Access Journals (Sweden)

Caren Lau

2015-01-01

Full Text Available Objective. To examine the effects of a 12-week Hatha yoga intervention on cardiorespiratory endurance, muscular strength and endurance, and flexibility in Chinese adults. Methods. 173 adults (aged 52.0 ± 7.5 years were assigned to either the yoga intervention group (n=87 or the waitlist control group (n=86. 19 dropped out from the study. Primary outcomes were changes in cardiorespiratory endurance (resting heart rate (HR and maximal oxygen uptake (VO2max, muscular strength and endurance (curl-up and push-up tests, and lower back and hamstring flexibility (the modified back-saver sit-and-reach (MBS test. Results. Compared to controls, the yoga group achieved significant improvements in VO2max (P<0.01, curl-up (P<0.05 and push-up (P<0.001 tests, and the MBS left and right leg tests (both P<0.001 in both genders. Significant change was also found for resting HR between groups in women (P<0.05 but not in men. Further analysis comparing participants between younger and older subgroups yielded similar findings, except that the older participants in the yoga group failed to improve resting HR or the curl-up test versus control. Adherence (89% and attendance (94% were high. No serious adverse events occurred. Conclusion. A 12-week Hatha yoga intervention has favorable effects on cardiorespiratory endurance, muscular strength and endurance, and flexibility in Chinese adults.

Caffeine improves endurance in 75-year old citizens. A randomized, double-blind, placebo-controlled, cross-over study

DEFF Research Database (Denmark)

Buchard Nørager, Charlotte; Jensen, Martin Bach; Madsen, Mogens Rørbæk

2005-01-01

This study investigated the effect of caffeine on physical performance in healthy citizens aged ≥70 yr. The randomized, double-blind, placebo-controlled, crossover study was conducted in 15 men and 15 women recruited by their general practitioner. Participants abstained from caffeine for 48 h...... and were randomized to receive one capsule of placebo and then caffeine (6 mg/kg) or caffeine and then placebo with 1 wk in between. One hour after intervention, we measured reaction and movement times, postural stability, walking speed, cycling at 65% of expected maximal heart rate, perceived effort...... during cycling, maximal isometric arm flexion strength, and endurance. Analysis was by intention to treat, and P Caffeine increased cycling endurance by 25% [95% confidence interval (CI): 13–38; P = 0.0001] and isometric arm flexion endurance by 54% (95% CI: 29–83; P...

Validity and Reliability of Curl-Up Test on Assessing the Core Endurance for Kindergarten Children in Hong Kong

OpenAIRE

Lai, CY; Lee, KY; Lams, MHS; Wu, CF; Peake, R; Flint, SW; Li, WHC; Ho, E

2017-01-01

Objective: The purpose of this study was to examine the test-retest reliability and the criterion validity of a curlup\\ud test (CUT) as a measure of core stability, core endurance and dynamic stability in kindergarten children. CUT\\ud performance was also compared to half hold lying test (HHLT) and walking time on course (WTC) among without\\ud obstacle, with low obstacle and high obstacle measures of core stability, core endurance and dynamic stability.\\ud Methods: To estimate reliability, 33...

Comparison of midterm results for the Talent and Endurant stent graft.

Science.gov (United States)

't Mannetje, Yannick W; Cuypers, Philippe W M; Saleem, Ben R; Bode, Aron S; Teijink, Joep A W; van Sambeek, Marc R H M

2017-09-01

Stent graft evolution is often addressed as a cause for improved outcomes of endovascular aneurysm repair for patients with an abdominal aortic aneurysm. In this study, we directly compared the midterm result of Endurant stent graft with its predecessor, the Talent stent graft (both Medtronic, Santa Rosa, Calif). Patient treated from January 2005 to December 2010 in a single tertiary center in The Netherlands with a Talent or Endurant stent graft were eligible for inclusion. Ruptured abdominal aortic aneurysms or patients with previous aortic surgery were excluded. The primary end point was the Kaplan-Meier estimated freedom from secondary interventions. Secondary end points were perioperative outcomes and indications for secondary interventions. In total, 221 patients were included (131 Endurant and 90 Talent). At baseline, the median aortic bifurcation was narrower for the Endurant (30 mm vs 39 mm; P Talent and Endurant, respectively. The estimated freedom from secondary interventions at 30 days, 1 year, 5 years, and 7 years was 94.3%, 89.4%, 72.2%, and 64.1% for Talent and 96.8%, 89.3%, 75.2%, and 69.2% for Endurant (P = .528). The indication for secondary interventions does differ; more patients required an intervention for a proximal neck-related complication (type Ia endoleak or migration) in the Talent group (18.2% vs 4.8%; P = .001), whereas more interventions for iliac limb stenosis were seen in the Endurant group (0.0% vs 4.8%; P = .044). In a binomial regression analysis, suprarenal angulation, infrarenal neck length, and type of stent graft were independent predictors of neck-related complications. Evolution from the Talent stent graft into the Endurant has resulted in significant reduction of infrarenal neck-related complications; on the other hand, iliac interventions increased. The overall midterm secondary intervention rate was comparable. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Within-day energy deficiency and metabolic perturbation in male endurance athletes

DEFF Research Database (Denmark)

Torstveit, Monica K; Fahrenholtz, Ida Lysdahl; Stenqvist, Thomas B

2018-01-01

) or normal RMR (RMRratio> 0.90, n=11). Despite no observed differences in 24-hour EB or EA between the groups, subjects with suppressed RMR spent more time in an energy deficit exceeding 400 kcal (20.9 [18.8 - 21.8] hours vs. 10.8 [2.5 - 16.4], P=0.023), and had larger single-hour energy deficits compared......Endurance athletes are at increased risk of relative energy deficiency associated with metabolic perturbation and impaired health. We aimed to estimate and compare within-day energy balance (WDEB) in male athletes with suppressed and normal resting metabolic rate (RMR) and explore if within...... to subjects with normal RMR (3265 ± 1963 kcal vs. -1340 ± 2439, P=0.023). Larger single-hour energy deficits were associated with higher cortisol levels (r = -0.499, P=0.004) and a lower testosterone:cortisol ratio (r = 0.431, P=0.015), but no associations with T3or fasting blood glucose were observed...

Soccer Endurance Development in Professionals

NARCIS (Netherlands)

Roescher, C. R.; Elferink-Gemser, M. T.; Huijgen, B. C. H.; Visscher, C.

The development of intermittent endurance capacity, its underlying mechanisms and role in reaching professional level in soccer was investigated. The sample included 130 talented youth soccer players aged 14-18, who became professional (n = 53) or non-professional (n = 77) players in adulthood. In

Efficacy of a Multimodal Cognitive Rehabilitation Including Psychomotor and Endurance Training in Parkinson's Disease

Directory of Open Access Journals (Sweden)

I. Reuter

2012-01-01

Full Text Available Mild cognitive impairment, especially executive dysfunction might occur early in the course of Parkinson's disease. Cognitive training is thought to improve cognitive performance. However, transfer of improvements achieved in paper and pencil tests into daily life has been difficult. The aim of the current study was to investigate whether a multimodal cognitive rehabilitation programme including physical exercises might be more successful than cognitive training programmes without motor training. 240 PD-patients were included in the study and randomly allocated to three treatment arms, group A cognitive training, group B cognitive training and transfer training and group C cognitive training, transfer training and psychomotor and endurance training. The primary outcome measure was the ADAS-Cog. The secondary outcome measure was the SCOPA-Cog. Training was conducted for 4 weeks on a rehabilitation unit, followed by 6 months training at home. Caregivers received an education programme. The combination of cognitive training using paper and pencil and the computer, transfer training and physical training seems to have the greatest effect on cognitive function. Thus, patients of group C showed the greatest improvement on the ADAS-Cog and SCOPA-COG and were more likely to continue with the training programme after the study.

Interaction of training and diet on metabolism and endurance during exercise in man

DEFF Research Database (Denmark)

Helge, Jørn Wulff; Richter, Erik; Kiens, Bente

1996-01-01

-FAT. After 8 weeks, RER in both T-CHO and T-FAT/CHO was approximately 0.87. 5. During exercise, plasma noradrenaline concentration and heart rate were higher in T-FAT than in T-CHO both at 7 and at 8 weeks. 6. It is concluded that ingesting a fat-rich diet during an endurance training programme......1. Ten untrained young men ingested a carbohydrate-rich diet (65 energy percent (E%) carbohydrate, T-CHO) and ten similar subjects a fat-rich diet (62 E% fat, T-FAT) while endurance training was performed 3-4 times a week for 7 weeks. For another 8th week of training both groups ingested...... the carbohydrate-rich diet (T-CHO and T-FAT/CHO). 2. Maximal oxygen uptake increased by 11% (P

Influence of mental workload on muscle endurance, fatigue, and recovery during intermittent static work.

Science.gov (United States)

Mehta, Ranjana K; Agnew, Michael J

2012-08-01

Most occupational tasks involve some level of mental/cognitive processing in addition to physical work; however, the etiology of work-related musculoskeletal disorders (WMSDs) due to these demands remains unclear. The aim of this study was to quantify the interactive effects of physical and mental workload on muscle endurance, fatigue, and recovery during intermittent work. Twelve participants, balanced by gender, performed intermittent static shoulder abductions to exhaustion at 15, 35, and 55% of individual maximal voluntary contraction (MVC), in the absence (control) and presence (concurrent) of a mental arithmetic task. Changes in muscular capacity were determined using endurance time, strength decline, electromyographic (EMG) fatigue indicators, muscle oxygenation, and heart rate measures. Muscular recovery was quantified through changes in strength and physiological responses. Mental workload was associated with shorter endurance times, specifically at 35% MVC, and greater strength decline. EMG and oxygenation measures showed similar changes during fatigue manifestation during concurrent conditions compared to the control, despite shorter endurance times. Moreover, decreased heart rate variability during concurrent demand conditions indicated increased mental stress. Although strength recovery was not influenced by mental workload, a slower heart rate recovery was observed after concurrent demand conditions. The findings from this study provide fundamental evidence that physical capacity (fatigability and recovery) is adversely affected by mental workload. Thus, it is critical to determine or evaluate occupational demands based on modified muscular capacity (due to mental workload) to reduce risk of WMSD development.

Motor performance in children with Noonan syndrome.

Science.gov (United States)

Croonen, Ellen A; Essink, Marlou; van der Burgt, Ineke; Draaisma, Jos M; Noordam, Cees; Nijhuis-van der Sanden, Maria W G

2017-09-01

Although problems with motor performance in daily life are frequently mentioned in Noonan syndrome, the motor performance profile has never been systematically investigated. The aim of this study was to examine whether a specific profile in motor performance in children with Noonan syndrome was seen using valid norm-referenced tests. The study assessed motor performance in 19 children with Noonan syndrome (12 females, mean age 9 years 4 months, range 6 years 1 month to 11 years and 11 months, SDS 1 year and 11 months). More than 60% of the parents of the children reported pain, decreased muscle strength, reduced endurance, and/or clumsiness in daily functioning. The mean standard scores on the Visual Motor Integration (VMI) test and Movement Assessment Battery for Children 2, Dutch version (MABC-2-NL) items differed significantly from the reference scores. Grip strength, muscle force, and 6 min Walking Test (6 MWT) walking distance were significantly lower, and the presence of generalized hypermobility was significantly higher. All MABC-2-NL scores (except manual dexterity) correlated significantly with almost all muscle strength tests, VMI total score, and VMI visual perception score. The 6 MWT was only significantly correlated to grip strength. This is the first study that confirms that motor performance, strength, and endurance are significantly impaired in children with Noonan syndrome. Decreased functional motor performance seems to be related to decreased visual perception and reduced muscle strength. Research on causal relationships and the effectiveness of interventions is needed. Physical and/or occupational therapy guidance should be considered to enhance participation in daily life. © 2017 Wiley Periodicals, Inc.

Prevalence of exertional rhabdomyolysis in endurance horses in the Pacific Northwestern United States.

Science.gov (United States)

Wilberger, M S; McKenzie, E C; Payton, M E; Rigas, J D; Valberg, S J

2015-03-01

Exertional rhabdomyolysis (ER) is a reported syndrome in competing endurance horses; however, the prevalence and cause of ER in this population have not been defined. To determine the prevalence of ER in a sample of endurance racing horses and investigate factors, including relevant genetic defects, contributing to the occurrence of rhabdomyolysis in this group. Prospective clinical study. Riders of 101 horses participating in one of four 50-mile (80.5 km) distance races completed a comprehensive questionnaire regarding the medical history, management and performance of their horse. Serum creatine kinase activity (CK) was measured before and 4 h after completion of exercise. Hair samples were analysed by PCR for the R309H mutation in the glycogen synthase gene (GYS1) responsible for type 1 polysaccharide storage myopathy (PSSM) and the C7360G mutation in the ryanodine receptor 1 (RYR1) gene causing malignant hyperthermia (MH). Samples were obtained from 68 Arabians, 20 half-Arabians and 13 horses of other breeds. Serum CK was above the resting reference interval (145-633 u/l) in 38 horses after racing (median 883 u/l, range 658-3739) but was compatible with values previously reported in apparently healthy endurance horses. Pathological ER was suspected to occur in 4 horses with serum CK activities exceeding 10,000 u/l 4 h after racing (median 84,825 u/l; range 10,846-381,790) including 3 Arabians and one half-Arabian horse. GYS1 and RYR1 mutations were not present in hair samples from any horses. Exertional rhabdomyolysis occurred at a prevalence of 4.0% in a sample of horses participating in 50 mile distance events and all affected horses were Arabian or half-Arabian. The cause of ER in the endurance horse population remains unknown; however, ER in competing Arabian endurance horses is unlikely to be due to type 1 PSSM or MH. © 2014 EVJ Ltd.

Anti-fatigue and vasoprotective effects of quercetin-3-O-gentiobiose on oxidative stress and vascular endothelial dysfunction induced by endurance swimming in rats.

Science.gov (United States)

Lin, Yin; Liu, Hua-Liang; Fang, Jie; Yu, Chen-Huan; Xiong, Yao-Kang; Yuan, Ke

2014-06-01

Chronic fatigue accumulation increases the incidence of cardiovascular disease while the treatment of antioxidants could prevent this development. We have previously shown that quercetin-3-O-gentiobiose (QG), a flavonoid isolated from tonic herb Okra, possesses anti-oxidative properties. In the present study, the protective effects of QG were evaluated in a rat model of load-induced endurance swimming. Oral administration of QG at the doses of 25-75mg/kg could significantly improve the endurance capability of rats to fatigue along with decrease serum lactic acid and blood urea nitrogen levels were decreased. Moreover, QG could alleviate vascular impairments, enhance the activities of antioxidant enzymes and attenuate the levels of inflammatory cytokines (MCP-1, IL-6 and TNF-α). The results indicated that QG had anti-fatigue and vasoprotective effects and represented a potential agent for the treatment of aortic pathology involved with fatigue- and related syndrome. Copyright © 2014 Elsevier Ltd. All rights reserved.

‘The engine just started coughing!’ — Limits of physical performance, aging and career continuity in elite endurance sports

DEFF Research Database (Denmark)

Ronkainen, Noora; Ryba, Tatiana; Nesti, Mark

2013-01-01

This research examines male endurance athletes' experience of aging and/or reaching the perceived limits of physical performance. More specifically, the current study aimed to explore how existential meanings attached to these experiences are connected with athletes' decision-making concerning...... career continuity and retirement. Life story interviews were conducted with 10 Finnish runners and/or orienteers aged between 25 and 62 and the data was analyzed with an existential-narrative framework. Four major storylines related to aging were identified: The end of an era, putting things...... the normativity of retirement when unable to improve their results anymore, other athletes demonstrated career continuity and positive aspects in the late career years, such as lack of competitive anxiety, finding perspective and increased enjoyment in running. We suggest that through awareness of alternative...

Long-term low-calorie low-protein vegan diet and endurance exercise are associated with low cardiometabolic risk.

Science.gov (United States)

Fontana, Luigi; Meyer, Timothy E; Klein, Samuel; Holloszy, John O

2007-06-01

Western diets, which typically contain large amounts of energy-dense processed foods, together with a sedentary lifestyle are associated with increased cardiometabolic risk. We evaluated the long-term effects of consuming a low-calorie low-protein vegan diet or performing regular endurance exercise on cardiometabolic risk factors. In this cross-sectional study, cardiometabolic risk factors were evaluated in 21 sedentary subjects, who had been on a low-calorie low-protein raw vegan diet for 4.4 +/- 2.8 years, (mean age, 53.1 +/- 11 yrs), 21 body mass index (BMI)-matched endurance runners consuming Western diets, and 21 age- and gender-matched sedentary subjects, consuming Western diets. BMI was lower in the low-calorie low-protein vegan diet (21.3 +/- 3.1 kg/m(2)) and endurance runner (21.1 +/- 1.6 kg/m(2)) groups than in the sedentary Western diet group (26.5 +/- 2.7 kg/m(2)) (p vegan diet and runner groups than in the Western diet group (all p vegan diet group (104 +/- 15 and 62 +/- 11 mm Hg) than in BMI-matched endurance runners (122 +/- 13 and 72 +/- 9 mmHg) and Western diet group (132 +/- 14 and 79 +/- 8 mm Hg) (p vegan diet or regular endurance exercise training is associated with low cardiometabolic risk. Moreover, our data suggest that specific components of a low-calorie low-protein vegan diet provide additional beneficial effects on blood pressure.

Masked hypertension and cardiac remodeling in middle-aged endurance athletes

OpenAIRE

Trachsel, Lukas; Carlen, Frederic; Brugger, Nicolas Jacques; Seiler, Christian; Wilhelm, Matthias

2015-01-01

OBJECTIVES: Extensive endurance training and arterial hypertension are established risk factors for atrial fibrillation. We aimed to assess the proportion of masked hypertension in endurance athletes and the impact on cardiac remodeling, mechanics, and supraventricular tachycardias (SVT). METHODS: Male participants of a 10-mile race were recruited and included if office blood pressure was normal (

The impact of visual impairment on the ability to perform activities of daily living for persons with severe/profound intellectual disability.

Science.gov (United States)

Dijkhuizen, Annemarie; Hilgenkamp, Thessa I M; Krijnen, Wim P; van der Schans, Cees P; Waninge, Aly

2016-01-01

The ability to perform activities of daily living (ADL) as a component of participation is one of the factors that contribute to quality of life. The ability to perform ADL for persons experiencing severe/profound intellectual disability (ID) may be reduced due to their cognitive and physical capacities. However, until recently, the impact of the significantly prevalent visual impairments on the performance of activities of daily living has not yet been revealed within this group. The purpose of this prospective cross-sectional study was to investigate the impact of visual impairment on the performance of activities of daily living for persons with a severe/profound intellectual disability. The Barthel Index (BI) and Comfortable Walking Speed (CWS) were used to measure the ability of performing activities of daily living (ADL) in 240 persons with severe/profound ID and having Gross Motor Functioning Classification System (GMFCS) levels I, II or III; this included 120 persons with visual impairment. The impact of visual impairment on ADL was analyzed with linear regression. The results of the study demonstrated that visual impairment slightly affects the ability of performing activities of daily living (BI) for persons experiencing a severe/profound intellectual disability. GMFCS Levels II or III, profound ID level, and visual impairment each have the effect of lowering BI scores. GMFCS Levels II or III, and profound ID level each have the effect of increasing CWS scores, which indicates a lower walking speed. A main effect of visual impairment is present on CWS, but our results do show a substantive interaction effect between GMFCS level III and visual impairment on Comfortable Walking Speed in persons with a severe/profound intellectual disability. Visual impairment has a slight effect on ability to perform ADL in persons experiencing severe/profound ID. Copyright © 2015 Elsevier Ltd. All rights reserved.

Work-related stress is associated with impaired neuropsychological test performance: a clinical cross-sectional study.

Science.gov (United States)

Eskildsen, Anita; Andersen, Lars Peter; Pedersen, Anders Degn; Vandborg, Sanne Kjær; Andersen, Johan Hviid

2015-01-01

Patients on sick leave due to work-related stress often complain about impaired concentration and memory. However, it is undetermined how widespread these impairments are, and which cognitive domains are most long-term stress sensitive. Previous studies show inconsistent results and are difficult to synthesize. The primary aim of this study was to examine whether patients with work-related stress complaints have cognitive impairments compared to a matched control group without stress. Our secondary aim was to examine whether the level of self-reported perceived stress is associated with neuropsychological test performance. We used a broad neuropsychological test battery to assess 59 outpatients with work-related stress complaints (without major depression) and 59 healthy controls. We matched the patients and controls pairwise by sex, age and educational level. Compared to controls, patients generally showed mildly reduced performance across all the measured domains of the neuropsychological test battery. However, only three comparisons reached statistical significance (p working memory. There were no statistical significant associations between self-reported perceived stress level and neuropsychological test performance. In conclusion, we recommend that cognitive functions should be considered when evaluating patients with work-related stress complaints, especially when given advice regarding return to work. Since this study had a cross-sectional design, it is still uncertain whether the impairments are permanent. Further study is required to establish causal links between work-related stress and cognitive deficits.

Endurance training in mild hypertension - effects on ambulatory blood pressure and neural circulatory control.

Science.gov (United States)

Narkiewicz; Somers

1997-10-01

This review examines the effects of a single bout of exercise and of endurance training on blood pressure in patients with hypertension. Possible autonomic mechanisms that mediate these changes in blood pressure are reviewed briefly. Blood pressure rises during exercise. During the second half hour after exercise blood pressure is lower. This p;ost-exercise reduction in blood pressure is associated with a decrease in muscle sympathetic nerve activity, an increase in baroreflex gain and a reduction in the level of blood pressure (set point) at which baroreflex activation occurs. The post-exercise fall in blood pressure appears to be limited to several hours and is not likely to explain any chronic reduction in blood pressure from endurance training. Endurance training elicits modest (approximately 4-5 mmHg) reductions in blood pressure. Because of the intrinsic variability of blood pressure, the decreases in blood pressure after endurance training is evident, especially when multiple measurements of blood pressure are obtained. Studies using 24 h blood pressure measurements suggest that, although endurance training lowers daytime blood pressure, blood pressure during sleep remains unchanged. The mechanism underlying the reduction in blood pressure in endurance training is not known. Although physical fitness is known to attenuate the sympathetic response to acute exercise, whether resting sympathetic drive is decreased with endurance training remains controversial. The slowing of heart rate that accompanies endurance training is also associated with an increase in variability of heart rate. The slower heart rate, increased variability of heart rate and lower blood pressure after endurance training are accompanied by an increase in baroreflex sensitivity. Even though the antihypertensive effect of endurance training is modest, the favourable effects of physical fitness on other risk factors for cardiovascular disease make exercise training an important approach in

Impact of Short-Term Training Camp on Aortic Blood Pressure in Collegiate Endurance Runners

Directory of Open Access Journals (Sweden)

Tsubasa Tomoto

2018-03-01

Full Text Available To investigate the influence of short-term vigorous endurance training on aortic blood pressure (BP, pulse wave analysis was performed in 36 highly trained elite collegiate endurance runners before and after a 7-day intense training camp. Subjects participated three training sessions per day, which mainly consisted of long distance running and sprint training to reach the daily target distance of 26 km. After the camp, they were divided into two groups based on whether the target training was achieved. Aortic systolic BP, pulse pressure, and tension-time index (TTI, a surrogate index of the myocardial oxygen demand were significantly elevated after the camp in the accomplished group but not in the unaccomplished group, whereas the brachial BP remained unchanged in both groups. The average daily training distance was significantly correlated with the changes in aortic systolic BP (r = 0.608, p = 0.0002, pulse pressure (r = 0.415, p = 0.016, and TTI (r = 0.438, p = 0.011. These results suggest that aortic BP is affected by a short-term vigorous training camp even in highly trained elite endurance athletes presumably due to a greater training volume compared to usual.

The comparison of stress and marital satisfaction status of parents of hearing-impaired and normal children

Directory of Open Access Journals (Sweden)

Karim Gharashi

2013-03-01

Full Text Available Background and Aim: Stress is the source of many problems in human-kind lives and threatens people's life constantly. Having hearing-impaired child, not only causes stress in parents, but also affects their marital satisfaction. The purpose of this study was comparing the stress and marital satisfaction status between the normal and hearing-impaired children's parents.Methods: This was a causal-comparative study. Eighty parents of normal children and 80 parents of hearing-impaired children were chosen from rehabilitation centers and kindergartens in city of Tabriz, Iran by available and clustering sampling method. All parents were asked to complete the Friedrich's source of stress and Enrich marital satisfaction questionnaires.Results: Parents of hearing-impaired children endure more stress than the normal hearing ones (p<0.001. The marital satisfaction of hearing-impaired children's parents was lower than the parents of normal hearing children, too (p<0.001.Conclusion: Having a hearing-impaired child causes stress and threatens the levels of marital satisfaction. This requires much more attention and a distinct planning for parents of handicap children to reduce their stress.

Total Energy Expenditure, Energy Intake, and Body Composition in Endurance Athletes Across the Training Season: A Systematic Review.

Science.gov (United States)

Heydenreich, Juliane; Kayser, Bengt; Schutz, Yves; Melzer, Katarina

2017-12-01

Endurance athletes perform periodized training in order to prepare for main competitions and maximize performance. However, the coupling between alterations of total energy expenditure (TEE), energy intake, and body composition during different seasonal training phases is unclear. So far, no systematic review has assessed fluctuations in TEE, energy intake, and/or body composition in endurance athletes across the training season. The purpose of this study was to (1) systematically analyze TEE, energy intake, and body composition in highly trained athletes of various endurance disciplines and of both sexes and (2) analyze fluctuations in these parameters across the training season. An electronic database search was conducted on the SPORTDiscus and MEDLINE (January 1990-31 January 2015) databases using a combination of relevant keywords. Two independent reviewers identified potentially relevant studies. Where a consensus was not reached, a third reviewer was consulted. Original research articles that examined TEE, energy intake, and/or body composition in 18-40-year-old endurance athletes and reported the seasonal training phases of data assessment were included in the review. Articles were excluded if body composition was assessed by skinfold measurements, TEE was assessed by questionnaires, or data could not be split between the sexes. Two reviewers assessed the quality of studies independently. Data on subject characteristics, TEE, energy intake, and/or body composition were extracted from the included studies. Subjects were categorized according to their sex and endurance discipline and each study allocated a weight within categories based on the number of subjects assessed. Extracted data were used to calculate weighted means and standard deviations for parameters of TEE, energy intake, and/or body composition. From 3589 citations, 321 articles were identified as potentially relevant, with 82 meeting all of the inclusion criteria. TEE of endurance athletes was

A Typology of Marital Quality of Enduring Marriages in Israel

Science.gov (United States)

Cohen, Orna; Geron, Yael; Farchi, Alva

2010-01-01

This article presents a typology of enduring marriages of Israeli couples married for at least 40 years. Based on the view that marital quality is a multidimensional phenomenon, the typology is derived from a cluster analysis of responses of husbands and wives in 51 couples to the ENRICH scale items. Three types of enduring marriages were found:…

Comparative analysis of endurance of not hearing and hearing students

Directory of Open Access Journals (Sweden)

Iwańska Dagmara

2013-11-01

Full Text Available Study aim: Sport participation is important for deaf children, as participants experience physical, psychological and social benefits [23]. This study is a summary of four year’s researches on the endurance level of deaf and well hearing girls and boys. The aim of this study was to compare endurance of not hearing and hearing students.

Markers of muscle damage and performance recovery after exercise in the heat.

Science.gov (United States)

Nybo, Lars; Girard, Olivier; Mohr, Magni; Knez, Wade; Voss, Sven; Racinais, Sebastien

2013-05-01

This study aimed to determine whether competitive intermittent exercise in the heat affects recovery, aggravates markers of muscle fiber damage, and delays the recovery of performance and muscle glycogen stores. Plasma creatine kinase, serum myoglobin, muscle glycogen, and performance parameters (sprint, endurance, and neuromuscular testing) were evaluated in 17 semiprofessional soccer players before, immediately after, and during 48 h of recovery from a match played in 43°C (HOT) and compared with a control match (21°C with similar turf and setup). Muscle temperature was ∼1°C higher (P recovery. Creatine kinase was significantly elevated both immediately and 24 h after the matches, but the response after HOT was reduced compared with control. Muscle glycogen responses were similar across trials and remained depressed for more than 48 h after both matches. Sprint performance and voluntary muscle activation were impaired to a similar extent after the matches (sprint by ∼2% and voluntary activation by ∼1.5%; P heat stress does not aggravate the recovery response from competitive intermittent exercise associated with elevated muscle temperatures and markers of muscle damage, delayed resynthesis of muscle glycogen, and impaired postmatch performance.

The Role of Eif6 in Skeletal Muscle Homeostasis Revealed by Endurance Training Co-expression Networks

Directory of Open Access Journals (Sweden)

Kim Clarke

2017-11-01

Full Text Available Regular endurance training improves muscle oxidative capacity and reduces the risk of age-related disorders. Understanding the molecular networks underlying this phenomenon is crucial. Here, by exploiting the power of computational modeling, we show that endurance training induces profound changes in gene regulatory networks linking signaling and selective control of translation to energy metabolism and tissue remodeling. We discovered that knockdown of the mTOR-independent factor Eif6, which we predicted to be a key regulator of this process, affects mitochondrial respiration efficiency, ROS production, and exercise performance. Our work demonstrates the validity of a data-driven approach to understanding muscle homeostasis.

Mental Fatigue: Impairment of Technical Performance in Small-Sided Soccer Games.

Science.gov (United States)

Badin, Oliver O; Smith, Mitchell R; Conte, Daniele; Coutts, Aaron J

2016-11-01

To assess the effects of mental fatigue on physical and technical performance in small-sided soccer games. Twenty soccer players (age 17.8 ± 1.0 y, height 179 ± 5 cm, body mass 72.4 ± 6.8 kg, playing experience 8.3 ± 1.4 y) from an Australian National Premier League soccer club volunteered to participate in this randomized crossover investigation. Participants played 15-min 5-vs-5 small-sided games (SSGs) without goalkeepers on 2 occasions separated by 1 wk. Before the SSG, 1 team watched a 30-min emotionally neutral documentary (control), while the other performed 30 min of a computer-based Stroop task (mental fatigue). Subjective ratings of mental and physical fatigue were recorded before and after treatment and after the SSG. Motivation was assessed before treatment and SSG; mental effort was assessed after treatment and SSG. Player activity profiles and heart rate (HR) were measured throughout the SSG, whereas ratings of perceived exertion (RPEs) were recorded before the SSG and immediately after each half. Video recordings of the SSG allowed for notational analysis of technical variables. Subjective ratings of mental fatigue and effort were higher after the Stroop task, whereas motivation for the upcoming SSG was similar between conditions. HR during the SSG was possibly higher in the control condition, whereas RPE was likely higher in the mental-fatigue condition. Mental fatigue had an unclear effect on most physical-performance variables but impaired most technical-performance variables. Mental fatigue impairs technical but not physical performance in small-sided soccer games.

THE RELATIONSHIP BETWEEN TRUNK MUSCLES ENDURANCE AND NORMAL BMI AMONG UNIVERSITY STUDENTS WITH SEDENTARY LIFESTYLE

Directory of Open Access Journals (Sweden)

Karthikeyan Selvaganapathy

2017-12-01

Full Text Available Background: The most important trunk stabilizers are the trunk flexors and extensors. The isometric endurance of the trunk muscles is an essential element for mechanical support of the spine in all positions. The study objectives were to find out the trunk flexors and extensors endurance, its relationship with normal BMI and to find out the ratio of trunk flexors to extensors endurance. Methods: In this correlation study, 50 subjects were selected by convenience sampling method on the basis of inclusion and exclusion criteria from Asia metropolitan university, Malaysia. The trunk flexors and extensors endurance were assessed by Kraus- Weber and Sorenson test respectively. Paired 't' test and Spearman correlation test were used for data analysis. Results: There was a significant difference (p 0.01 and TEE, rs (50 = -0.162, p >0.01 but there was a significant strong positive relationship between TFE and TEE, rs (50 = 0.68, p < 0.01. The ratio of trunk flexors to extensors was 0.61. Conclusion: The trunk extensors endurance is higher than trunk flexors endurance and BMI has no relationship with trunk flexors and extensors muscle endurance. The ratio of trunk flexors to extensors endurance value is low

Performance of the Hack's Impairment Index Score: A Novel Tool to Assess Impairment from Alcohol in Emergency Department Patients.

Science.gov (United States)

Hack, Jason B; Goldlust, Eric J; Ferrante, Dennis; Zink, Brian J

2017-10-01

Over 35 million alcohol-impaired (AI) patients are cared for in emergency departments (EDs) annually. Emergency physicians are charged with ensuring AI patients' safety by identifying resolution of alcohol-induced impairment. The most common standard evaluation is an extemporized clinical examination, as ethanol levels are not reliable or predictive of clinical symptoms. There is no standard assessment of ED AI patients. The objective was to evaluate a novel standardized ED assessment of alcohol impairment, Hack's Impairment Index (HII score), in a busy urban ED. A retrospective chart review was performed for all AI patients seen in our busy urban ED over 24 months. Trained nurses evaluated AI patients with both "usual" and HII score every 2 hours. Patients were stratified by frequency of visits for AI during this time: high (≥ 6), medium (2-5), and low (1). Within each category, comparisons were made between HII scores, measured ethanol levels, and usual nursing assessment of AI. Changes in HII scores over time were also evaluated. A total of 8,074 visits from 3,219 unique patients were eligible for study, including 7,973 (98.7%) with ethanol levels, 5,061 (62.7%) with complete HII scores, and 3,646 (45.2%) with health care provider assessments. Correlations between HII scores and ethanol levels were poor (Pearson's R 2  = 0.09, 0.09, and 0.17 for high-, medium-, and low-frequency strata). HII scores were excellent at discriminating nursing assessment of AI, while ethanol levels were less effective. Omitting extrema, HII scores fell consistently an average 0.062 points per hour, throughout patients' visits. The HII score applied a quantitative, objective assessment of alcohol impairment. HII scores were superior to ethanol levels as an objective clinical measure of impairment. The HII declines in a reasonably predictable manner over time, with serial evaluations corresponding well with health care provider evaluations. © 2017 by the Society for Academic

Effect of intensified training on muscle ion kinetics, fatigue development and repeated short term performance in endurance trained cyclists

DEFF Research Database (Denmark)

Gunnarsson, Thomas Gunnar Petursson; Christensen, Peter Møller; Thomassen, Martin

2013-01-01

The effects of intensified training in combination with a reduced training volume on muscle ion kinetics, transporters and work capacity were examined. Eight well-trained cyclists replaced their regular training with speed-endurance training (12x30-s sprints) 2-3 times per wk and aerobic high...

Arctigenin enhances swimming endurance of sedentary rats partially by regulation of antioxidant pathways.

Science.gov (United States)

Wu, Ruo-ming; Sun, Yan-yan; Zhou, Ting-ting; Zhu, Zhi-yuan; Zhuang, Jing-jing; Tang, Xuan; Chen, Jing; Hu, Li-hong; Shen, Xu

2014-10-01

Arctigenin, a phenylpropanoid dibenzylbutyrolactone lignan found in traditional Chinese herbs, has been determined to exhibit a variety of pharmacological activities, including anti-tumor, anti-inflammation, neuroprotection, and endurance enhancement. In the present study, we investigated the antioxidation and anti-fatigue effects of arctigenin in rats. Rat L6 skeletal muscle cell line was exposed to H2O2 (700 μmol/L), and ROS level was assayed using DCFH-DA as a probe. Male SD rats were injected with arctigenin (15 mg·kg(-1)·d(-1), ip) for 6 weeks, and then the weight-loaded forced swimming test (WFST) was performed to evaluate their endurance. The levels of antioxidant-related genes in L6 cells and the skeletal muscles of rats were analyzed using real-time RT-PCR and Western blotting. Incubation of L6 cells with arctigenin (1, 5, 20 μmol/L) dose-dependently decreased the H2O2-induced ROS production. WFST results demonstrated that chronic administration of arctigenin significantly enhanced the endurance of rats. Furthermore, molecular biology studies on L6 cells and skeletal muscles of the rats showed that arctigenin effectively increased the expression of the antioxidant-related genes, including superoxide dismutase (SOD), glutathione reductase (Gsr), glutathione peroxidase (GPX1), thioredoxin (Txn) and uncoupling protein 2 (UCP2), through regulation of two potential antioxidant pathways: AMPK/PGC-1α/PPARα in mitochondria and AMPK/p53/Nrf2 in the cell nucleus. Arctigenin efficiently enhances rat swimming endurance by elevation of the antioxidant capacity of the skeletal muscles, which has thereby highlighted the potential of this natural product as an antioxidant in the treatment of fatigue and related diseases.

Stability of functional impairment in patients with schizotypal, borderline, avoidant, or obsessive–compulsive personality disorder over two years

Science.gov (United States)

SKODOL, ANDREW E.; PAGANO, MARIA E.; BENDER, DONNA S.; SHEA, M. TRACIE; GUNDERSON, JOHN G.; YEN, SHIRLEY; STOUT, ROBERT L.; MOREY, LESLIE C.; SANISLOW, CHARLES A.; GRILO, CARLOS M.; ZANARINI, MARY C.; McGLASHAN, THOMAS H.

2012-01-01

Background A defining feature of personality disorder (PD) is an enduring pattern of inner experience and behavior that is stable over time. Follow-up and follow-along studies have shown considerable diagnostic instability of PDs, however, even over short intervals. What, then, about personality disorder is stable ? The purpose of this study was to determine the stability of impairment in psychosocial functioning in patients with four different PDs, in contrast to patients with major depressive disorder (MDD) and no PD, prospectively over a 2-year period. Method Six hundred treatment-seeking or treated patients were recruited primarily from clinical services in four metropolitan areas of the Northeastern USA. Patients were assigned to one of five diagnostic groups: schizotypal (STPD) (n=81), borderline (BPD) (n=155), avoidant (AVPD) (n=137), or obsessive–compulsive (OCPD) (n=142) personality disorders or MDD and no PD (n=85), based on the results of semi-structured interview assessments and self-report measures. Impairment in psychosocial functioning was measured using the Longitudinal Interval Follow-up Evaluation (LIFE) at baseline and at three follow-up assessments. Results Significant improvement in psychosocial functioning occurred in only three of seven domains of functioning and was largely the result of improvements in the MDD and no PD group. Patients with BPD or OCPD showed no improvement in functioning overall, but patients with BPD who experienced change in personality psychopathology showed some improvement in functioning. Impairment in social relationships appeared most stable in patients with PDs. Conclusion Impairment in functioning, especially social functioning, may be an enduring component of personality disorder. PMID:15841879

TNFα G308A polymorphism is associated with resilience to sleep deprivation-induced psychomotor vigilance performance impairment in healthy young adults.

Science.gov (United States)

Satterfield, Brieann C; Wisor, Jonathan P; Field, Stephanie A; Schmidt, Michelle A; Van Dongen, Hans P A

2015-07-01

Cytokines such as TNFα play an integral role in sleep/wake regulation and have recently been hypothesized to be involved in cognitive impairment due to sleep deprivation. We examined the effect of a guanine to adenine substitution at position 308 in the TNFα gene (TNFα G308A) on psychomotor vigilance performance impairment during total sleep deprivation. A total of 88 healthy women and men (ages 22-40) participated in one of five laboratory total sleep deprivation experiments. Performance on a psychomotor vigilance test (PVT) was measured every 2-3h. The TNFα 308A allele, which is less common than the 308G allele, was associated with greater resilience to psychomotor vigilance performance impairment during total sleep deprivation (regardless of time of day), and also provided a small performance benefit at baseline. The effect of genotype on resilience persisted when controlling for between-subjects differences in age, gender, race/ethnicity, and baseline sleep duration. The TNFα G308A polymorphism predicted less than 10% of the overall between-subjects variance in performance impairment during sleep deprivation. Nonetheless, the differential effect of the polymorphism at the peak of performance impairment was more than 50% of median performance impairment at that time, which is sizeable compared to the effects of other genotypes reported in the literature. Our findings provided evidence for a role of TNFα in the effects of sleep deprivation on psychomotor vigilance performance. Furthermore, the TNFα G308A polymorphism may have predictive potential in a biomarker panel for the assessment of resilience to psychomotor vigilance performance impairment due to sleep deprivation. Copyright © 2014 Elsevier Inc. All rights reserved.

Age, sex and (the) race: gender and geriatrics in the ultra-endurance age.

Science.gov (United States)

Whyte, Greg

2014-01-01

Ultra-endurance challenges were once the stuff of legend isolated to the daring few who were driven to take on some of the greatest physical endurance challenges on the planet. With a growing fascination for major physical challenges during the nineteenth century, the end of the Victorian era witnessed probably the greatest ultra-endurance race of all time; Scott and Amundsen's ill-fated race to the South Pole. Ultra-endurance races continued through the twentieth century; however, these events were isolated to the elite few. In the twenty-first century, mass participation ultra-endurance races have grown in popularity. Endurance races once believed to be at the limit of human durability, i.e. marathon running, are now viewed as middle-distance races with the accolade of true endurance going to those willing to travel significantly further in a single effort or over multiple days. The recent series of papers in Extreme Physiology & Medicine highlights the burgeoning research data from mass participation ultra-endurance events. In support of a true 'mass participation' ethos Knetchtle et al. reported age-related changes in Triple and Deca Iron-ultra-triathlon with an upper age of 69 years! Unlike their shorter siblings, the ultra-endurance races appear to present larger gender differences in the region of 20% to 30% across distance and modality. It would appear that these gender differences remain for multi-day events including the 'Marathon des Sables'; however, this gap may be narrower in some events, particularly those that require less load bearing (i.e. swimming and cycling), as evidenced from the 'Ultraman Hawaii' and 'Swiss Cycling Marathon', and shorter (a term I used advisedly!) distances including the Ironman Triathlon where differences are similar to those of sprint and endurance distances i.e. c. 10%. The theme running through this series of papers is a continual rise in participation to the point where major events now require selection races to remain

Negative Emotional Arousal Impairs Associative Memory Performance for Emotionally Neutral Content in Healthy Participants.

Directory of Open Access Journals (Sweden)

Jonathan Guez

Full Text Available The effect of emotional arousal on memory presents a complex pattern with previous studies reporting conflicting results of both improved and reduced memory performance following arousal manipulations. In this study we further tested the effect of negative emotional arousal (NEA on individual-item recognition and associative recognition of neutral stimuli in healthy participants, and hypothesized that NEA will particularly impair associative memory performance. The current study consists of two experiments; in both, participants studied a list of word-pairs and were then tested for items (items recognition test, and for associations (associative recognition test. In the first experiment, the arousal manipulation was induced by flashing emotionally-negative or neutral pictures between study-pairs while in the second experiment arousal was induced by presenting emotionally-negative or neutral pictures between lists. The results of the two experiments converged and supported an associative memory deficit observed under NEA conditions. We suggest that NEA is associated with an altered ability to bind one stimulus to another as a result of impaired recollection, resulting in poorer associative memory performance. The current study findings may contribute to the understanding of the mechanism underlying memory impairments reported in disorders associated with traumatic stress.

Alcohol effects on simulated driving performance and self-perceptions of impairment in DUI offenders.

Science.gov (United States)

Van Dyke, Nicholas; Fillmore, Mark T

2014-12-01

Drivers with a history of driving under the influence (DUI) of alcohol self-report heightened impulsivity and display reckless driving behaviors as indicated by increased rates of vehicle crashes, moving violations, and traffic tickets. Such poor behavioral self-regulation could also increase sensitivity to the disruptive effects of alcohol on driving performance. The present study examined the degree to which DUI drivers display an increased sensitivity to the acute impairing effects of alcohol on simulated driving performance and overestimate their driving fitness following alcohol consumption. Adult drivers with a history of DUI and a demographically matched group of drivers with no history of DUI (controls) were tested following a 0.65 g/kg alcohol and a placebo. Results indicated that alcohol impaired several measures of driving performance, and there was no difference between DUI offenders and controls in these impairments. However, following alcohol, DUI drivers self-reported a greater ability and willingness to drive compared with controls. These findings indicate that drivers with a history of DUI might perceive themselves as more fit to drive after drinking, which could play an important role in their decisions to drink and drive. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Real-time and accelerated outdoor endurance testing of solar cells

Science.gov (United States)

Forestieri, A. F.; Anagnostou, E.

1977-01-01

Real-time and accelerated outdoor endurance testing was performed on a variety of samples of interest to the National Photovoltaic Conversion Program. The real-time tests were performed at seven different sites and the accelerated tests were performed at one of those sites in the southwestern United States. The purpose of the tests were to help evaluate the lifetime of photovoltaic systems. Three types of samples were tested; transmission samples of possible cover materials, sub-modules constructed using these materials attached to solar cells, and solar cell modules produced by the manufacturers for the ERDA program. Results indicate that suitable cover materials are glass, FEP-A and PFA. Dirt accumulation and cleanability are important factors in the selection of solar cell module covers and encapsulants.

Concurrent Training for Sports Performance: The Two Sides of the Medal.

Science.gov (United States)

Berryman, Nicolas; Mujika, Inigo; Bosquet, Laurent

2018-05-29

The classical work by Robert C. Hickson showed in 1980 that the addition of a resistance training protocol to a predominantly aerobic program could lead to impaired leg strength adaptations in comparison to a resistance-only training regimen. This interference phenomenon was later highlighted in many reports, including a meta-analysis. However, it seems that the interference effect has not been consistently reported, probably because of the complex interactions between training variables and methodological issues. On the other side of the medal, Dr Hickson and colleagues subsequently (1986) reported that a strength training mesocycle could be beneficial for endurance performance in running and cycling. In recent meta-analyses and review articles, it was demonstrated that such a training strategy could improve middle- and long-distance performance in many disciplines (running, cycling, cross-country skiing and swimming). Interestingly, it appears that improvements in the energy cost of locomotion could be associated with these performance enhancements. Despite these benefits, it was also reported that strength training could represent a detrimental stimulus for endurance performance if an inappropriate training plan has been prepared. Taken together, these observations suggest that coaches and athletes should be careful when concurrent training seems imperative in order to meet the complex physiological requirements of their sport. Therefore, this brief review will present a practical appraisal of concurrent training for sports performance. In addition, recommendations will be provided so that practitioners could adapt their interventions based on the training objectives.

Ketogenic diet benefits body composition and well-being but not performance in a pilot case study of New Zealand endurance athletes.

Science.gov (United States)

Zinn, Caryn; Wood, Matthew; Williden, Mikki; Chatterton, Simon; Maunder, Ed

2017-01-01

Low-carbohydrate, high-fat and ketogenic diets are increasingly adopted by athletes for body composition and sports performance enhancements. However, as yet, there is no consensus on their efficacy in improving performance. There is also no comprehensive literature on athletes' experiences while undertaking this diet. The purpose of this pilot work was two-fold: i. to examine the effects of a non-calorie controlled ketogenic diet on body composition and performance outcomes of endurance athletes, and ii. to evaluate the athletes' experiences of the ketogenic diet during the 10-week intervention. Using a case study design, five New Zealand endurance athletes (4 females, 1 male) underwent a 10-week ketogenic dietary intervention. Body composition (sum of 8 skinfolds), performance indicators (time to exhaustion, VO 2 max, peak power and ventilatory threshold), and gas exchange thresholds were measured at baseline and at 10 weeks. Mean change scores were calculated, and analysed using t-tests; Cohen's effect sizes and 90% confidence limits were applied to quantify change. Individual interviews conducted at 5 weeks and a focus group at 10 weeks assessed athletes' ketogenic diet experiences. Data was transcribed and analysed using thematic analysis. All athletes increased their ability to utilise fat as a fuel source, including at higher exercise intensities. Mean body weight was reduced by 4 kg ± SD 3.1 ( p  = 0.046; effect size (ES):0.62), and sum of 8 skinfolds by 25.9 mm ± SD 6.9; ES: 1.27; p  = 0.001). Mean time to exhaustion dropped by ~2 min (±SD 0.7; p  = 0.004; ES: 0.53). Other performance outcomes showed mean reductions, with some increases or unchanged results in two individuals (VO2 Max: -1.69 ml.kg.min ± SD 3.4 ( p  = 0.63); peak power: -18 W ± SD 16.4 ( p  = 0.07), and VT2: -6 W ± SD 44.5 ( p  = 0.77). Athletes reported experiencing reduced energy levels initially, followed by a return of high levels thereafter

Plutonium in an enduring fuel cycle

International Nuclear Information System (INIS)

Pillay, K.K.S.

1998-05-01

Nuclear fuel cycles evolved over the past five decades have allowed many nations of the world to enjoy the benefits of nuclear energy, while contributing to the sustainable consumption of the world's energy resources. The nuclear fuel cycle for energy production suffered many traumas since the 1970s because of perceived risks of proliferation of nuclear weapons. However, the experience of the past five decades has shown that the world community is committed to safeguarding all fissile materials and continuing the use of nuclear energy resources. Decisions of a few nations to discard spent nuclear fuels in geologic formations are contrary to the goals of an enduring nuclear fuel cycle and sustainable development being pursued by the world community. The maintenance of an enduring nuclear fuel cycle is dependent on sensible management of all the resources of the fuel cycle, including spent fuels

The influence of unilateral saccular impairment on functional balance performance and self-report dizziness.

Science.gov (United States)

McCaslin, Devin L; Jacobson, Gary P; Grantham, Sarah L; Piker, Erin G; Verghese, Susha

2011-09-01

Postural stability in humans is largely maintained by vestibular, visual, and somatosensory inputs to the central nervous system. Recent clinical advances in the assessment of otolith function (e.g., cervical and ocular vestibular evoked myogenic potentials [cVEMPs and oVEMPs], subjective visual vertical [SVV] during eccentric rotation) have enabled investigators to identify patients with unilateral otolith impairments. This research has suggested that patients with unilateral otolith impairments perform worse than normal healthy controls on measures of postural stability. It is not yet known if patients with unilateral impairments of the saccule and/or inferior vestibular nerve (i.e., unilaterally abnormal cVEMP) perform differently on measures of postural stability than patients with unilateral impairments of the horizontal SCC (semicircular canal) and/or superior vestibular nerve (i.e., unilateral caloric weakness). Further, it is not known what relationship exists, if any, between otolith system impairment and self-report dizziness handicap. The purpose of this investigation was to determine the extent to which saccular impairments (defined by a unilaterally absent cVEMP) and impairments of the horizontal semicircular canal (as measured by the results of caloric testing) affect vestibulospinal function as measured through the Sensory Organization Test (SOT) of the computerized dynamic posturography (CDP). A secondary objective of this investigation was to measure the effects, if any, that saccular impairment has on a modality-specific measure of health-related quality of life. A retrospective cohort study. Subjects were assigned to one of four groups based on results from balance function testing: Group 1 (abnormal cVEMP response only), Group 2 (abnormal caloric response only), Group 3 (abnormal cVEMP and abnormal caloric response), and Group 4 (normal control group). Subjects were 92 adult patients: 62 were seen for balance function testing due to complaints

Ketone Diester Ingestion Impairs Time-Trial Performance in Professional Cyclists

Directory of Open Access Journals (Sweden)

Jill J. Leckey

2017-10-01

Full Text Available We investigated the effect of pre- “race” ingestion of a 1,3-butanediol acetoacetate diester on blood ketone concentration, substrate metabolism and performance of a cycling time trial (TT in professional cyclists. In a randomized cross-over design, 10 elite male cyclists completed a ~31 km laboratory-based TT on a cycling ergometer programmed to simulate the 2017 World Road Cycling Championships course. Cyclists consumed a standardized meal [2 g/kg body mass (BM carbohydrate (CHO] the evening prior to a trial day and a CHO breakfast (2 g/kg BM CHO with 200 mg caffeine on the morning of a trial day. Cyclists were randomized to consume either the ketone diester (2 × 250 mg/kg or a placebo drink, followed immediately by 200 mL diet cola, given ~ 30 min before and immediately prior to commencing a 20 min incremental warm-up. Blood samples were collected prior to and during the warm-up, pre- and post- TT and at regular intervals after the TT. Urine samples were collected pre- and post- warm-up, immediately post TT and 60 min post TT. Pre-exercise ingestion of the diester resulted in a 2 ± 1% impairment in TT performance that was associated with gut discomfort and higher perception of effort. Serum β-hydroxybutyrate, serum acetoacetate, and urine ketone concentrations increased from rest following ketone ingestion and were higher than placebo throughout the trial. Ketone ingestion induces hyperketonemia in elite professional cyclists when in a carbohydrate fed state, and impairs performance of a cycling TT lasting ~50 min.

Short-term moderate intensive high volume training program provides aerobic endurance benefit in wheelchair basketball players.

Science.gov (United States)

Skucas, Kestutis; Pokvytyte, Vaida

2017-04-01

The aim of this paper was to investigate the effect of short-term period, moderate intensity and high volume endurance training on physiological variables in elite wheelchair basketball players. Eight wheelchair basketball players were examined. The subjects participated in a two-week intervention program of mainly two training types: wheelchair basketball and wheelchair driving endurance training. The subjects performed the continuously increasing cycling exercise (CCE) at the constant 60 rpm arm cranking speed at the beginning of the program and after two weeks of the program. The initial workload was 20 W, then the workload was increased by 2 W every 5 seconds until fatigue. The post training of the wheelchair basketball group in the study showed a significant improvement in the peak oxygen uptake (VO2peak) and the peak power output (POpeak). VO2peak increased by 9% from 2.32±0.16 L/min to 2.53±0.2 L/min (Pbasketball squad had relatively high levels of aerobic fitness prior to participating in the endurance training program. Nevertheless, the high-volume, moderate-intensity, short-term training program, which evolved over the two-weeks period, resulted in the improvement of the athlete's aerobic endurance. The ventilatory threshold (VT) and the second ventilatory threshold (VT2) are good markers for aerobic capacity of wheelchair athletes.

Wechsler Memory Scale-III Faces test performance in patients with mild cognitive impairment and mild Alzheimer's disease.

Science.gov (United States)

Seelye, Adriana M; Howieson, Diane B; Wild, Katherine V; Moore, Mindy Milar; Kaye, Jeffrey A

2009-08-01

Little is known about the sensitivity of the Wechsler Memory Scale-Third Edition (WMS-III) Faces subtest to memory impairment associated with mild cognitive impairment (MCI). In this study, Faces performance was examined in 24 MCI patients, 46 mild Alzheimer's disease (AD) patients, and 98 elderly controls. We hypothesized that participants with diagnoses of MCI or AD would be impaired relative to controls on Faces. Analyses showed that AD participants performed significantly worse than MCI and intact participants, although there were no significant differences between MCI and intact participants. Data suggest that brain areas specialized for face recognition memory may be less affected by MCI and mild AD than regions specialized for verbal memory.

Gait and Cognition in Parkinson’s Disease: Cognitive Impairment Is Inadequately Reflected by Gait Performance during Dual Task

Directory of Open Access Journals (Sweden)

Heiko Gaßner

2017-10-01

Full Text Available IntroductionCognitive and gait deficits are common symptoms in Parkinson’s disease (PD. Motor-cognitive dual tasks (DTs are used to explore the interplay between gait and cognition. However, it is unclear if DT gait performance is indicative for cognitive impairment. Therefore, the aim of this study was to investigate if cognitive deficits are reflected by DT costs of spatiotemporal gait parameters.MethodsCognitive function, single task (ST and DT gait performance were investigated in 67 PD patients. Cognition was assessed by the Montreal Cognitive Assessment (MoCA followed by a standardized, sensor-based gait test and the identical gait test while subtracting serial 3’s. Cognitive impairment was defined by a MoCA score <26. DT costs in gait parameters [(DT − ST/ST × 100] were calculated as a measure of DT effect on gait. Correlation analysis was used to evaluate the association between MoCA performance and gait parameters. In a linear regression model, DT gait costs and clinical confounders (age, gender, disease duration, motor impairment, medication, and depression were correlated to cognitive performance. In a subgroup analysis, we compared matched groups of cognitively impaired and unimpaired PD patients regarding differences in ST, DT, and DT gait costs.ResultsCorrelation analysis revealed weak correlations between MoCA score and DT costs of gait parameters (r/rSp ≤ 0.3. DT costs of stride length, swing time variability, and maximum toe clearance (|r/rSp| > 0.2 were included in a regression analysis. The parameters only explain 8% of the cognitive variance. In combination with clinical confounders, regression analysis showed that these gait parameters explained 30% of MoCA performance. Group comparison revealed strong DT effects within both groups (large effect sizes, but significant between-group effects in DT gait costs were not observed.ConclusionThese findings suggest that DT gait performance is not indicative

Endurance exercise as an endogenous neuro-enhancement strategy to facilitate motor learning

Directory of Open Access Journals (Sweden)

Marco eTaubert

2015-12-01

Full Text Available Endurance exercise improves cardiovascular and musculoskeletal function and may also increase the information processing capacities of the brain. Animal and human research from the past decade demonstrated widespread exercise effects on brain structure and function at the systems-, cellular- and molecular level of brain organization. These neurobiological mechanisms may explain the well-established positive influence of exercise on performance in various behavioural domains but also its contribution to improved skill learning and neuroplasticity. With respect to the latter, only few empirical and theoretical studies are available to date. The aim of this review is (i to summarize the existing neurobiological and behavioural evidence arguing for endurance exercise-induced improvements in motor learning and (ii to develop hypotheses about the mechanistic link between exercise and improved learning. We identify major knowledge gaps that need to be addressed by future research projects to advance our understanding of how exercise should be organized to optimize motor learning.

Record Endurance for Single-Walled Carbon Nanotube–Based Memory Cell

Directory of Open Access Journals (Sweden)

Yang Y

2010-01-01

Full Text Available Abstract We study memory devices consisting of single-walled carbon nanotube transistors with charge storage at the SiO2/nanotube interface. We show that this type of memory device is robust, withstanding over 105 operating cycles, with a current drive capability up to 10−6 A at 20 mV drain bias, thus competing with state-of-the-art Si-devices. We find that the device performance depends on temperature and pressure, while both endurance and data retention are improved in vacuum.

Effects of moderate and heavy endurance exercise on nocturnal HRV.

Science.gov (United States)

Hynynen, E; Vesterinen, V; Rusko, H; Nummela, A

2010-06-01

This study examined the effects of endurance exercise on nocturnal autonomic modulation. Nocturnal R-R intervals were collected after a rest day, after a moderate endurance exercise and after a marathon run in ten healthy, physically active men. Heart rate variability (HRV) was analyzed as a continuous four-hour period starting 30 min after going to bed for sleep. In relation to average nocturnal heart rate after rest day, increases to 109+/-6% and 130+/-11% of baseline were found after moderate endurance exercise and marathon, respectively. Standard deviation of R-R intervals decreased to 90+/-9% and 64+/-10%, root-mean-square of differences between adjacent R-R intervals to 87+/-10% and 55+/-16%, and high frequency power to 77+/-19% and 34+/-19% of baseline after moderate endurance exercise and marathon, respectively. Also nocturnal low frequency power decreased to 56+/-26% of baseline after the marathon. Changes in nocturnal heart rate and HRV suggest prolonged dose-response effects on autonomic modulation after exercises, which may give useful information on the extent of exercise-induced nocturnal autonomic modulation and disturbance to the homeostasis.

Within-Day Energy Deficiency and Metabolic Perturbation in Male Endurance Athletes.

Science.gov (United States)

Torstveit, Monica Klungland; Fahrenholtz, Ida; Stenqvist, Thomas B; Sylta, Øystein; Melin, Anna

2018-06-26

Endurance athletes are at increased risk of relative energy deficiency associated with metabolic perturbation and impaired health. We aimed to estimate and compare within-day energy balance in male athletes with suppressed and normal resting metabolic rate (RMR) and explore whether within-day energy deficiency is associated with endocrine markers of energy deficiency. A total of 31 male cyclists, triathletes, and long-distance runners recruited from regional competitive sports clubs were included. The protocol comprised measurements of RMR by ventilated hood and energy intake and energy expenditure to predict RMR ratio (measured RMR/predicted RMR), energy availability, 24-hr energy balance and within-day energy balance in 1-hr intervals, assessment of body composition by dual-energy X-ray absorptiometry, and blood plasma analysis. Subjects were categorized as having suppressed (RMR ratio   0.90, n = 11) RMR. Despite there being no observed differences in 24-hr energy balance or energy availability between the groups, subjects with suppressed RMR spent more time in an energy deficit exceeding 400 kcal (20.9 [18.8-21.8] hr vs. 10.8 [2.5-16.4], p = .023) and had larger single-hour energy deficits compared with subjects with normal RMR (3,265 ± 1,963 kcal vs. -1,340 ± 2,439, p = .023). Larger single-hour energy deficits were associated with higher cortisol levels (r = -.499, p = .004) and a lower testosterone:cortisol ratio (r = .431, p = .015), but no associations with triiodothyronine or fasting blood glucose were observed. In conclusion, within-day energy deficiency was associated with suppressed RMR and catabolic markers in male endurance athletes.

Cognitive function affects trainability for physical performance in exercise intervention among older adults with mild cognitive impairment.

Science.gov (United States)

Uemura, Kazuki; Shimada, Hiroyuki; Makizako, Hyuma; Doi, Takehiko; Yoshida, Daisuke; Tsutsumimoto, Kota; Anan, Yuya; Suzuki, Takao

2013-01-01

Although much evidence supports the hypothesis that cognitive function and physical function are interrelated, it is unclear whether cognitive decline with mild cognitive impairment influences trainability of physical performance in exercise intervention. The purpose of this study was to examine the association between cognitive function at baseline and change in physical performance after exercise intervention in older adults with mild cognitive impairment. Forty-four older adults diagnosed with mild cognitive impairment based on the Peterson criteria (mean age 74.8 years) consented to and completed a 6-month twice weekly exercise intervention. The Timed Up and Go (TUG) test was used as a measure of physical performance. The Mini-Mental State Examination (MMSE), Trail Making Test Part B, Geriatric Depression Scale, baseline muscle strength of knee extension, and attendance rate of intervention, were measured as factors for predicting trainability. In the correlation analysis, the change in TUG showed modest correlations with attendance rate in the exercise program (r = -0.354, P = 0.027) and MMSE at baseline (r = -0.321, P = 0.034). A multiple regression analysis revealed that change in TUG was independently associated with attendance rate (β = -0.322, P = 0.026) and MMSE score (β = -0.295, P = 0.041), controlling for age and gender. General cognitive function was associated with improvements in physical performance after exercise intervention in subjects with mild cognitive impairment. Further research is needed to examine the effects of exercise programs designed to address cognitive obstacles in older adults with mild cognitive impairment.

Increasing the electrical discharge endurance of acid anhydride cured DGEBA epoxy resin by dispersion of nanoparticle silica. High Perform. Polym. 11 (1999) pp 281-296 by IOP Publishing Ltd

DEFF Research Database (Denmark)

Henk, Peter O; Kortsen, T.W.; Kvarts, T.

1999-01-01

combinations were used: (a) fumed nanoparticle silicon dioxide referred to as Aerosil, (b) equal volumes of Aerosil and nanoparticle anatase, and (c) Aerosil plus anatase in combination with coarse-particle filler grade calcium-magnesium carbonate dolomite. A test for endurance using the CIGRE method II...... electrode arrangement was applied, the test comprising the establishment of partial discharges running perpendicularly onto one face of a plate specimen for a period measured until breakdown.Our results show that the endurance of the pure polymer is low. Increased loading with Aerosil increases...... the endurance by a factor of up to 20 as the Aerosil content goes from zero to 5.4 vol%. Aerosil mixed with anatase has a similar effect. The high level of endurance is maintained with an additional high-volume (35 vol.%) filling of coarse-particle dolomite to an epoxy system already containing Aerosil...

Impaired theta-gamma coupling during working memory performance in schizophrenia.

Science.gov (United States)

Barr, Mera S; Rajji, Tarek K; Zomorrodi, Reza; Radhu, Natasha; George, Tony P; Blumberger, Daniel M; Daskalakis, Zafiris J

2017-11-01

Working memory deficits represent a core feature of schizophrenia. These deficits have been associated with dysfunctional dorsolateral prefrontal cortex (DLPFC) cortical oscillations. Theta-gamma coupling describes the modulation of gamma oscillations by theta phasic activity that has been directly associated with the ordering of information during working memory performance. Evaluating theta-gamma coupling may provide greater insight into the neural mechanisms mediating working memory deficits in this disorder. Thirty-eight patients diagnosed with schizophrenia or schizoaffective disorder and 38 healthy controls performed the verbal N-Back task administered at 4 levels, while EEG was recorded. Theta (4-7Hz)-gamma (30-50Hz) coupling was calculated for target and non-target correct trials for each working memory load. The relationship between theta-gamma coupling and accuracy was determined. Theta-gamma coupling was significantly and selectively impaired during correct responses to target letters among schizophrenia patients compared to healthy controls. A significant and positive relationship was found between theta-gamma coupling and 3-Back accuracy in controls, while this relationship was not observed in patients. These findings suggest that impaired theta-gamma coupling contribute to working memory dysfunction in schizophrenia. Future work is needed to evaluate the predictive utility of theta-gamma coupling as a neurophysiological marker for functional outcomes in this disorder. Copyright © 2017. Published by Elsevier B.V.

Modelling endurance and resumption times for repetitive one-hand pushing.

Science.gov (United States)

Rose, Linda M; Beauchemin, Catherine A A; Neumann, W Patrick

2018-07-01

This study's objective was to develop models of endurance time (ET), as a function of load level (LL), and of resumption time (RT) after loading as a function of both LL and loading time (LT) for repeated loadings. Ten male participants with experience in construction work each performed 15 different one-handed repetaed pushing tasks at shoulder height with varied exerted force and duration. These data were used to create regression models predicting ET and RT. It is concluded that power law relationships are most appropriate to use when modelling ET and RT. While the data the equations are based on are limited regarding number of participants, gender, postures, magnitude and type of exerted force, the paper suggests how this kind of modelling can be used in job design and in further research. Practitioner Summary: Adequate muscular recovery during work-shifts is important to create sustainable jobs. This paper describes mathematical modelling and presents models for endurance times and resumption times (an aspect of recovery need), based on data from an empirical study. The models can be used to help manage fatigue levels in job design.

Impaired financial capacity in late life depression is associated with cognitive performance on measures of executive functioning and attention.

Science.gov (United States)

Mackin, R Scott; Areán, Patricia A

2009-09-01

Few studies have evaluated the prevalence of impairments of financial capacity among individuals with psychiatric disorders. Late life depression (LLD) is a common psychiatric disorder associated with significant disability and cognitive impairment. The purpose of this investigation was to determine the prevalence and cognitive correlates of impairments of financial capacity among individuals with LLD. Participants included 65 LLD individuals and 32 comparison subjects. Assessments included measures of financial capacity, cognitive functioning, and depression symptom severity. Individuals with LLD exhibited a significantly higher rate of impaired financial capacity (22%) than the comparison group (6%). Results of a multiple regression analysis indicated that performance on measures of executive functioning and attention, but not depression severity, were most strongly associated with financial capacity performance in LLD. Our results suggest impairments of financial capacity in LLD are largely explained by cognitive functioning in these domains.

Long-term endurance sport is a risk factor for development of lone atrial flutter.

Science.gov (United States)

Claessen, Guido; Colyn, Erwin; La Gerche, André; Koopman, Pieter; Alzand, Becker; Garweg, Christophe; Willems, Rik; Nuyens, Dieter; Heidbuchel, Hein

2011-06-01

To evaluate whether in a population of patients with 'lone atrial flutter', the proportion of those engaged in long-term endurance sports is higher than that observed in the general population. An age and sex-matched retrospective case-control study. A database with 638 consecutive patients who underwent ablation for atrial flutter at the University of Leuven. Sixty-one patients (55 men, 90%) fitted the inclusion criteria of 'lone atrial flutter', ie, aged 65 years or less, without documented atrial fibrillation and without identifiable underlying disease (including hypertension). Sex, age and inclusion criteria-matched controls, two for each flutter patient, were selected in a general practice in the same geographical region. Sports activity was evaluated by detailed questionnaires, which were available in 58 flutter patients (95%). A transthoracic echocardiogram was performed in all lone flutter patients. Types of sports, number of years of participation and average number of hours per week. The proportion of regular sportsmen (≥3 h of sports practice per week) among patients with lone atrial flutter was significantly higher than that observed in the general population (50% vs 17%; pendurance sports (participation in cycling, running or swimming for ≥3 h/week) was also significantly higher in lone flutter patients than in controls (31% vs 8%; p=0.0003). Those flutter patients performing endurance sports had a larger left atrium than non-sportsmen (p=0.04, by one-way analysis of variance). A history of endurance sports and subsequent left atrial remodelling may be a risk factor for the development of atrial flutter.

Galectin-3 increase in endurance athletes

NARCIS (Netherlands)

Haettasch, Robert; Spethmann, Sebastian; de Boer, Rudolf A.; Ruifrok, Willem P. T.; Schattke, Sebastian; Wagner, Moritz; Schroeckh, Sabrina; Durmus, Tahir; Schimke, Ingolf; Sanad, Wasiem; Baumann, Gert; Borges, Adrian C.; Knebel, Fabian

2014-01-01

Background Galectin-3 is a new and promising biomarker for heart failure and myocardial fibrosis. Although endurance exercise is a crucial element in cardiovascular disease prevention, the relationship between exercise and plasma levels of galectin-3 is still unknown. To date, the relationship

The value of enduring environmental surrogates as predictors of estuarine benthic macroinvertebrate assemblages

Science.gov (United States)

Wildsmith, Michelle D.; Valesini, Fiona J.; Robinson, Samuel F.

2017-10-01

This study tested the extent to which spatial differences in the benthic macroinvertebrate assemblages of a temperate microtidal estuary were 'explained' by the enduring (biophysical) vs non-enduring (water and sediment quality) environmental attributes of a diverse range of habitats, and thus the potential of those environmental surrogates to support faunal prediction. Species composition differed significantly among habitats in each season, with the greatest differences occurring in winter and spring and the least in summer. The pattern of habitat differences, as defined by their enduring environmental characteristics, was significantly and well matched with that in the fauna in each season. In contrast, significant matches between the non-enduring environmental and faunal data were only detected in winter and/or spring, and to a lesser extent. Field validation of the faunal prediction capacity of the biophysical surrogate framework at various 'test' sites throughout the estuary showed good agreement between the actual vs predicted key species. These findings demonstrate that enduring environmental criteria, which can be readily measured from mapped data, provide a better and more cost-effective surrogate for explaining spatial differences in the invertebrate fauna of this system than non-enduring criteria, and are thus a promising basis for faunal prediction. The approaches developed in this study are also readily adapted to any estuary worldwide.

Endurance training enhances BDNF release from the human brain

DEFF Research Database (Denmark)

Seifert, Thomas; Brassard, Patrice; Wissenberg, Mads

2010-01-01

The circulating level of brain-derived neurotrophic factor (BDNF) is reduced in patients with major depression and type-2 diabetes. Because acute exercise increases BDNF production in the hippocampus and cerebral cortex, we hypothesized that endurance training would enhance the release of BDNF from...... the human brain as detected from arterial and internal jugular venous blood samples. In a randomized controlled study, 12 healthy sedentary males carried out 3 mo of endurance training (n = 7) or served as controls (n = 5). Before and after the intervention, blood samples were obtained at rest and during...... exercise. At baseline, the training group (58 + or - 106 ng x 100 g(-1) x min(-1), means + or - SD) and the control group (12 + or - 17 ng x 100 g(-1) x min(-1)) had a similar release of BDNF from the brain at rest. Three months of endurance training enhanced the resting release of BDNF to 206 + or - 108...

Impaired work performance among women with symptomatic uterine fibroids.

Science.gov (United States)

Lerner, Debra; Mirza, Fadi G; Mirza, Fadi; Chang, Hong; Renzulli, Karen; Perch, Katherine; Chelmow, David

2008-10-01

To assess the work impact of symptomatic uterine fibroids (UFs). A cohort study compared 58 employed women with symptomatic UFs to 56 healthy controls. Data sources included a self-administered mail questionnaire and medical charts. At-work performance limitations and productivity loss were measured with the Work Limitations Questionnaire. Univariate and multivariate case-control group differences were tested. Based on adjusted mean scores, the UF group had significantly more at-work limitations and productivity loss than controls, while absence rates were similar. The UF group's performance was impaired 18% of the time on average versus 8% for controls (P-values, 0.005-0.040). At-work limitations were explained by depression symptoms, Non-White race/ethnicity, and poorer health-related quality of life. Fibroids and related symptoms impose a burden on the working lives' of women, their employers, and the economy.

Arctigenin enhances swimming endurance of sedentary rats partially by regulation of antioxidant pathways

Science.gov (United States)

Wu, Ruo-ming; Sun, Yan-yan; Zhou, Ting-ting; Zhu, Zhi-yuan; Zhuang, Jing-jing; Tang, Xuan; Chen, Jing; Hu, Li-hong; Shen, Xu

2014-01-01

Aim: Arctigenin, a phenylpropanoid dibenzylbutyrolactone lignan found in traditional Chinese herbs, has been determined to exhibit a variety of pharmacological activities, including anti-tumor, anti-inflammation, neuroprotection, and endurance enhancement. In the present study, we investigated the antioxidation and anti-fatigue effects of arctigenin in rats. Methods: Rat L6 skeletal muscle cell line was exposed to H2O2 (700 μmol/L), and ROS level was assayed using DCFH-DA as a probe. Male SD rats were injected with arctigenin (15 mg·kg−1·d−1, ip) for 6 weeks, and then the weight-loaded forced swimming test (WFST) was performed to evaluate their endurance. The levels of antioxidant-related genes in L6 cells and the skeletal muscles of rats were analyzed using real-time RT-PCR and Western blotting. Results: Incubation of L6 cells with arctigenin (1, 5, 20 μmol/L) dose-dependently decreased the H2O2-induced ROS production. WFST results demonstrated that chronic administration of arctigenin significantly enhanced the endurance of rats. Furthermore, molecular biology studies on L6 cells and skeletal muscles of the rats showed that arctigenin effectively increased the expression of the antioxidant-related genes, including superoxide dismutase (SOD), glutathione reductase (Gsr), glutathione peroxidase (GPX1), thioredoxin (Txn) and uncoupling protein 2 (UCP2), through regulation of two potential antioxidant pathways: AMPK/PGC-1α/PPARα in mitochondria and AMPK/p53/Nrf2 in the cell nucleus. Conclusion: Arctigenin efficiently enhances rat swimming endurance by elevation of the antioxidant capacity of the skeletal muscles, which has thereby highlighted the potential of this natural product as an antioxidant in the treatment of fatigue and related diseases. PMID:25152028

Scapular muscle performance in individuals with lateral epicondylalgia.

Science.gov (United States)

Day, Joseph M; Bush, Heather; Nitz, Arthur J; Uhl, Tim L

2015-05-01

Descriptive, laboratory-based, cross-sectional study. To describe scapular musculature strength, endurance, and change in thickness in individuals with unilateral lateral epicondylalgia (LE) compared to the uninvolved limb and the corresponding limb of a matched comparison group. Reported poor long-term outcomes for the nonsurgical management of individuals with LE suggest a less-than-optimal rehabilitation process. Knowledge of scapular muscle function in a working population of individuals with LE may help to further refine conservative management of this condition. Twenty-eight patients with symptomatic LE and 28 controls matched by age and sex were recruited to participate in the study. Strength of the middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) was measured with a handheld dynamometer. A scapular isometric muscle endurance task was performed in prone. Changes in muscle thickness of the SA and LT were measured with ultrasound imaging. Analysis-of-variance models were used to determine within- and between-group differences. The involved side of the group with LE had significantly lower values for MT strength (P = .031), SA strength (PLE had significantly lower strength of the LT (P = .023) and SA (P = .016) when compared to the uninvolved limb; however, these differences were small and of potentially limited clinical significance. When compared to a matched comparison group, there were impairments of scapular musculature strength and endurance in patients with LE, suggesting that the scapular musculature should be assessed and potentially treated in this population. Cause and effect cannot be established, as the weakness of the scapular musculature could be a result of LE.

Eye gaze performance for children with severe physical impairments using gaze-based assistive technology-A longitudinal study.

Science.gov (United States)

Borgestig, Maria; Sandqvist, Jan; Parsons, Richard; Falkmer, Torbjörn; Hemmingsson, Helena

2016-01-01

Gaze-based assistive technology (gaze-based AT) has the potential to provide children affected by severe physical impairments with opportunities for communication and activities. This study aimed to examine changes in eye gaze performance over time (time on task and accuracy) in children with severe physical impairments, without speaking ability, using gaze-based AT. A longitudinal study with a before and after design was conducted on 10 children (aged 1-15 years) with severe physical impairments, who were beginners to gaze-based AT at baseline. Thereafter, all children used the gaze-based AT in daily activities over the course of the study. Compass computer software was used to measure time on task and accuracy with eye selection of targets on screen, and tests were performed with the children at baseline, after 5 months, 9-11 months, and after 15-20 months. Findings showed that the children improved in time on task after 5 months and became more accurate in selecting targets after 15-20 months. This study indicates that these children with severe physical impairments, who were unable to speak, could improve in eye gaze performance. However, the children needed time to practice on a long-term basis to acquire skills needed to develop fast and accurate eye gaze performance.

Potential Relationship between Passive Plantar Flexor Stiffness and Running Performance.

Science.gov (United States)

Ueno, Hiromasa; Suga, Tadashi; Takao, Kenji; Tanaka, Takahiro; Misaki, Jun; Miyake, Yuto; Nagano, Akinori; Isaka, Tadao

2018-02-01

The present study aimed to determine the relationship between passive stiffness of the plantar flexors and running performance in endurance runners. Forty-eight well-trained male endurance runners and 24 untrained male control subjects participated in this study. Plantar flexor stiffness during passive dorsiflexion was calculated from the slope of the linear portion of the torque-angle curve. Of the endurance runners included in the present study, running economy in 28 endurance runners was evaluated by measuring energy cost during three 4-min trials (14, 16, and 18 km/h) of submaximal treadmill running. Passive stiffness of the plantar flexors was significantly higher in endurance runners than in untrained subjects. Moreover, passive plantar flexor stiffness in endurance runners was significantly correlated with a personal best 5000-m race time. Furthermore, passive plantar flexor stiffness in endurance runners was significantly correlated with energy cost during submaximal running at 16 km/h and 18 km/h, and a trend towards such significance was observed at 14 km/h. The present findings suggest that stiffer plantar flexors may help achieve better running performance, with greater running economy, in endurance runners. Therefore, in the clinical setting, passive stiffness of the plantar flexors may be a potential parameter for assessing running performance. © Georg Thieme Verlag KG Stuttgart · New York.

Associations between Trunk Extension Endurance and Isolated Lumbar Extension Strength in Both Asymptomatic Participants and Those with Chronic Low Back Pain

Directory of Open Access Journals (Sweden)

Rebecca Conway

2016-09-01

Full Text Available Background: Strength and endurance tests are important for both clinical practice and research due to the key role they play in musculoskeletal function. In particular, deconditioning of the lumbar extensor musculature has been associated with low back pain (LBP. Due to the relationship between strength and absolute endurance, it is possible that trunk extension (TEX endurance tests could provide a proxy measure of isolated lumbar extension (ILEX strength and thus represent a simple, practical alternative to ILEX measurements. Though, the comparability of TEX endurance and ILEX strength is presently unclear and so the aim of the present study was to examine this relationship. Methods: Thirty eight healthy participants and nineteen participants with non-specific chronic LBP and no previous lumbar surgery participated in this cross-sectional study design. TEX endurance was measured using the Biering–Sorensen test. A maximal ILEX strength test was performed on the MedX lumbar-extension machine. Results: A Pearson’s correlation revealed no relationship between TEX endurance and ILEX strength in the combined group (r = 0.035, p = 0.793, the chronic LBP group (r = 0.120, p = 0.623 or the asymptomatic group (r = −0.060, p = 0.720. Conclusions: The results suggest that TEX is not a good indicator of ILEX and cannot be used to infer results regarding ILEX strength. However, a combination of TEX and ILEX interpreted together likely offers the greatest and most comprehensive information regarding lumbo-pelvic function during extension.

Restorative effect of endurance exercise on behavioral deficits in the chronic mouse model of Parkinson's disease with severe neurodegeneration

Science.gov (United States)

Pothakos, Konstantinos; Kurz, Max J; Lau, Yuen-Sum

2009-01-01

Background Animal models of Parkinson's disease have been widely used for investigating the mechanisms of neurodegenerative process and for discovering alternative strategies for treating the disease. Following 10 injections with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 25 mg/kg) and probenecid (250 mg/kg) over 5 weeks in mice, we have established and characterized a chronic mouse model of Parkinson's disease (MPD), which displays severe long-term neurological and pathological defects resembling that of the human Parkinson's disease in the advanced stage. The behavioral manifestations in this chronic mouse model of Parkinson's syndrome remain uninvestigated. The health benefit of exercise in aging and in neurodegenerative disorders including the Parkinson's disease has been implicated; however, clinical and laboratory studies in this area are limited. In this research with the chronic MPD, we first conducted a series of behavioral tests and then investigated the impact of endurance exercise on the identified Parkinsonian behavioral deficits. Results We report here that the severe chronic MPD mice showed significant deficits in their gait pattern consistency and in learning the cued version of the Morris water maze. Their performances on the challenging beam and walking grid were considerably attenuated suggesting the lack of balance and motor coordination. Furthermore, their spontaneous and amphetamine-stimulated locomotor activities in the open field were significantly suppressed. The behavioral deficits in the chronic MPD lasted for at least 8 weeks after MPTP/probenecid treatment. When the chronic MPD mice were exercise-trained on a motorized treadmill 1 week before, 5 weeks during, and 8–12 weeks after MPTP/probenecid treatment, the behavioral deficits in gait pattern, spontaneous ambulatory movement, and balance performance were reversed; whereas neuronal loss and impairment in cognitive skill, motor coordination, and amphetamine

Restorative effect of endurance exercise on behavioral deficits in the chronic mouse model of Parkinson's disease with severe neurodegeneration

Directory of Open Access Journals (Sweden)

Lau Yuen-Sum

2009-01-01

Full Text Available Abstract Background Animal models of Parkinson's disease have been widely used for investigating the mechanisms of neurodegenerative process and for discovering alternative strategies for treating the disease. Following 10 injections with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 25 mg/kg and probenecid (250 mg/kg over 5 weeks in mice, we have established and characterized a chronic mouse model of Parkinson's disease (MPD, which displays severe long-term neurological and pathological defects resembling that of the human Parkinson's disease in the advanced stage. The behavioral manifestations in this chronic mouse model of Parkinson's syndrome remain uninvestigated. The health benefit of exercise in aging and in neurodegenerative disorders including the Parkinson's disease has been implicated; however, clinical and laboratory studies in this area are limited. In this research with the chronic MPD, we first conducted a series of behavioral tests and then investigated the impact of endurance exercise on the identified Parkinsonian behavioral deficits. Results We report here that the severe chronic MPD mice showed significant deficits in their gait pattern consistency and in learning the cued version of the Morris water maze. Their performances on the challenging beam and walking grid were considerably attenuated suggesting the lack of balance and motor coordination. Furthermore, their spontaneous and amphetamine-stimulated locomotor activities in the open field were significantly suppressed. The behavioral deficits in the chronic MPD lasted for at least 8 weeks after MPTP/probenecid treatment. When the chronic MPD mice were exercise-trained on a motorized treadmill 1 week before, 5 weeks during, and 8–12 weeks after MPTP/probenecid treatment, the behavioral deficits in gait pattern, spontaneous ambulatory movement, and balance performance were reversed; whereas neuronal loss and impairment in cognitive skill, motor coordination, and

Arctigenin Efficiently Enhanced Sedentary Mice Treadmill Endurance

Science.gov (United States)

Chen, Jing; Yu, Liang; Hu, Lihong; Jiang, Hualiang; Shen, Xu

2011-01-01

Physical inactivity is considered as one of the potential risk factors for the development of type 2 diabetes and other metabolic diseases, while endurance exercise training could enhance fat oxidation that is associated with insulin sensitivity improvement in obesity. AMP-activated protein kinase (AMPK) as an energy sensor plays pivotal roles in the regulation of energy homeostasis, and its activation could improve glucose uptake, promote mitochondrial biogenesis and increase glycolysis. Recent research has even suggested that AMPK activation contributed to endurance enhancement without exercise. Here we report that the natural product arctigenin from the traditional herb Arctium lappa L. (Compositae) strongly increased AMPK phosphorylation and subsequently up-regulated its downstream pathway in both H9C2 and C2C12 cells. It was discovered that arctigenin phosphorylated AMPK via calmodulin-dependent protein kinase kinase (CaMKK) and serine/threonine kinase 11(LKB1)-dependent pathways. Mice treadmill based in vivo assay further indicated that administration of arctigenin improved efficiently mice endurance as reflected by the increased fatigue time and distance, and potently enhanced mitochondrial biogenesis and fatty acid oxidation (FAO) related genes expression in muscle tissues. Our results thus suggested that arctigenin might be used as a potential lead compound for the discovery of the agents with mimic exercise training effects to treat metabolic diseases. PMID:21887385

Arctigenin efficiently enhanced sedentary mice treadmill endurance.

Directory of Open Access Journals (Sweden)

Xuan Tang

Full Text Available Physical inactivity is considered as one of the potential risk factors for the development of type 2 diabetes and other metabolic diseases, while endurance exercise training could enhance fat oxidation that is associated with insulin sensitivity improvement in obesity. AMP-activated protein kinase (AMPK as an energy sensor plays pivotal roles in the regulation of energy homeostasis, and its activation could improve glucose uptake, promote mitochondrial biogenesis and increase glycolysis. Recent research has even suggested that AMPK activation contributed to endurance enhancement without exercise. Here we report that the natural product arctigenin from the traditional herb Arctium lappa L. (Compositae strongly increased AMPK phosphorylation and subsequently up-regulated its downstream pathway in both H9C2 and C2C12 cells. It was discovered that arctigenin phosphorylated AMPK via calmodulin-dependent protein kinase kinase (CaMKK and serine/threonine kinase 11(LKB1-dependent pathways. Mice treadmill based in vivo assay further indicated that administration of arctigenin improved efficiently mice endurance as reflected by the increased fatigue time and distance, and potently enhanced mitochondrial biogenesis and fatty acid oxidation (FAO related genes expression in muscle tissues. Our results thus suggested that arctigenin might be used as a potential lead compound for the discovery of the agents with mimic exercise training effects to treat metabolic diseases.

Correlation among personal, social performance and cognitive impairment in male schizophrenic patient

Science.gov (United States)

Damanik, R.; Effendy, E.; Camellia, V.

2018-03-01

Schizophrenia is a dramatic mental illness with tragic manifestation. The consequences of the illness are for the individual, affected his or her family and society. Schizophrenia is one of the twenty illness that causes Years Lost due to Disability. Treating only the symptom is insufficient. The aim of treatment must include the quality of life of aschizophrenic person. This study aims to examine the relationship between cognitive impairment and performance of the person with schizophrenia. Cognitive test is scaled with Indonesian version of Montreal Cognitive Assessment (MoCA-Ina), while personal and social performance isscaled with Personal and Social Performance scale. There are many studies that search the relationship between cognitive impairment and social functioning of schizophrenic patients, but this is the first study that uses PSP and MoCA-Ina. Both PSP and MoCA-Ina are easy to use but still have high sensitivity and specificity, and perhaps can build people’s interest to use it in clinical practice. Twenty-five male schizophrenic patients were assessed in Prof. M. Ildrem Mental Hospital of North Sumatera Province of Indonesia. Positive correlations between MoCA-Ina and PSP score were identified. Clinicians should pay attention to cognitive and might give some early intervention to it.

The Longitudinal Joint Effect of Obesity and Major Depression on Work Performance Impairment

NARCIS (Netherlands)

Nigatu, Yeshambel T.; Reijneveld, Sijmen A.; Penninx, Brenda W. J. H.; Schoevers, Robert A.; Bultmann, Ute

Objectives. We examined the longitudinal effect of obesity, major depression, and their combination on work performance impairment (WPI). Methods. We collected longitudinal data (2004-2013) on 1726 paid employees from the Netherlands Study of Depression and Anxiety at baseline and 2-, 4-, and 6-year

The longitudinal joint effect of obesity and major depression on work performance impairment

NARCIS (Netherlands)

Nigatu, Y.T.; Reijneveld, S.A.; Penninx, B.W.; Schoevers, R.A.; Bultmann, U.

2015-01-01

Objectives: We examined the longitudinal effect of obesity, major depression, and their combination on work performance impairment (WPI). Methods: We collected longitudinal data (2004-2013) on 1726 paid employees from the Netherlands Study of Depression and Anxiety at baseline and 2-, 4-, and 6-year

Intelligence Community Programs, Management, and Enduring Issues

Science.gov (United States)

2016-11-08

books, journal papers, conference presentations, working papers, and other electronic and print publications. Intelligence Community Programs... Intelligence Community Programs, Management, and Enduring Issues Anne Daugherty Miles Analyst in Intelligence and National Security Policy...

'Endurance' Courtesy of Mars Express

Science.gov (United States)

2004-01-01

NASA's Mars Exploration Rover Opportunity used its panoramic camera to capture this false-color image of the interior of 'Endurance Crater' on the rover's 188th martian day (Aug. 4, 2004). The image data were relayed to Earth by the European Space Agency's Mars Express orbiter. The image was generated from separate frames using the cameras 750-, 530- and 480-nanometer filters.

Effects of high intensity training and continuous endurance training on aerobic capacity and body composition in recreationally active runners.

Science.gov (United States)

Hottenrott, Kuno; Ludyga, Sebastian; Schulze, Stephan

2012-01-01

The aim of the study was to examine the effects of two different training programs (high-intensity-training vs. continuous endurance training) on aerobic power and body composition in recreationally active men and women and to test whether or not participants were able to complete a half marathon after the intervention period. Thirty-four recreational endurance runners were randomly assigned either to a Weekend-Group (WE, n = 17) or an After-Work- Group (AW, n = 17) for a 12 week-intervention period. WE weekly completed 2 h 30 min of continuous endurance running composed of 2 sessions on the weekend. In contrast, AW performed 4 30 min sessions of high intensity training and an additional 30 min endurance run weekly, always after work. During an exhaustive treadmill test aerobic power was measured and heart rate was continuously recorded. Body composition was assessed using bio-impedance. Following the intervention period all subjects took part in a half-marathon. AW significantly improved peak oxygen uptake (VO2 peak) from 36.8 ± 4.5 to 43.6 ± 6.5 [mL.min(-1).kg(-1)], velocity at lactate threshold (VLT) from 9.7 ± 2.2 to 11.7 ± 1.8 [km.h(-1)] and visceral fat from 5.6 ± 2.2 to 4.7 ± 1.9 In WE VO2 peak signifi-cantly increased from 38.8 ± 5.0 to 41.5 ± 6.0 [mL.min(-1).kg(-1)], VLT from 9.9 ± 1.3 to 11.2 ± 1.7 [km.h(-1)] and visceral fat was reduced from 5.7 ± 2.1 to 5.4 ± 1.9 (p marathon with no significant differences in performance (p = 0.63). Short, intensive endurance training sessions of about 30 min are effective in improving aerobic fitness in recreationally active runners. Key pointsContinuous endurance training and high intensity training lead to significant improvements of aerobic capacity and body compositionBoth training methods enable recreationally active runners to finish a half-marathonHigh intensity training is favorable to improve VO2 peak.

Role of creatine kinase isoenzymes on muscular and cardiorespiratory endurance: genetic and molecular evidence.

Science.gov (United States)

Echegaray, M; Rivera, M A

2001-01-01

The ability to perform well in activities that require muscular and cardiorespiratory endurance is a trait influenced, in a considerable part, by the genetic make-up of individuals. Early studies of performance and recent scans of the human genome have pointed at various candidate genes responsible for the heterogeneity of these phenotypes within the population. Among these are the genes for the various creatine kinase (CK) isoenzyme subunits. CK and phosphocreatine (PCr) form an important metabolic system for temporal and spatial energy buffering in cells with large variations in energy demand. The different CK isoenzyme subunits (CK-M and CK-B) are differentially expressed in the tissues of the body. Although CK-M is the predominant form in both skeletal and cardiac muscle, CK-B is expressed to a greater extent in heart than in skeletal muscle. Studies in humans and mice have shown that the expression of CK-B messenger RNA (mRNA) and the abundance and activity of the CK-MB dimer increase in response to cardiorespiratory endurance training. Increases in muscle tissue CK-B content can be energetically favourable because of its lower Michaelis constant (Km) for ADP. The activity of the mitochondrial isoform of CK (Scmit-CK) has also been significantly and positively correlated to oxidative capacity and to CK-MB activity in muscle. In mice where the CK-M gene has been knocked out, significant increases in fatigue resistance together with cellular adaptations increasing aerobic capacity have been observed. These observations have led to the notion that this enzyme may be responsible for fatigue under normal circumstances, most likely because of the local cell compartment increase in inorganic phosphate concentration. Studies where the Scmit-CK gene was knocked out have helped demonstrate that this isoenzyme is very important for the stimulation of aerobic respiration. Human studies of CK-M gene sequence variation have shown a significant association between a

Ecological validity and reliability of an age-adapted endurance field test in young male soccer players

DEFF Research Database (Denmark)

Castagna, Carlo; Krustrup, Peter; D'Ottavio, Stefano

2018-01-01

The purpose of this study was to examine the reliability and the association with relevant match activities (ecological validity) of an age-adapted field test for intermittent high-intensity endurance known as Yo-Yo intermittent recovery level 1 children test (YYIR1C) in young male soccer players......-intensity metabolic power (r=0.46) distances. Match total distance was largely associated with YYIR1C (r=0.30). The results of this study showed that YYIR1C may be considered a valid and reliable field test for assessing intermittent high-intensity endurance in young male soccer players. Due to the relevance...... performance showed an excellent relative (ICC=0.94) and a good absolute reliability (TEM as %CV=5.1%). Very large and significant associations were found between YYIR1C performance and match high-intensity activity (r=0.53). Large correlations were found between YYIR1C and match sprinting (r=0.42) and high...

Impairment of exercise performance following cold water immersion is not attenuated after 7 days of cold acclimation.

Science.gov (United States)

Jones, Douglas M; Roelands, Bart; Bailey, Stephen P; Buono, Michael J; Meeusen, Romain

2018-03-19

It is well-documented that severe cold stress impairs exercise performance. Repeated immersion in cold water induces an insulative type of cold acclimation, wherein enhanced vasoconstriction leads to greater body heat retention, which may attenuate cold-induced exercise impairments. The purpose of this study, therefore, was to investigate changes in exercise performance during a 7-day insulative type of cold acclimation. Twelve healthy participants consisting of eight males and four females (mean ± SD age: 25.6 ± 5.2 years, height: 174.0 ± 8.9 cm, weight: 75.6 ± 13.1 kg) performed a 20 min self-paced cycling test in 23 °C, 40% humidity without prior cold exposure. Twenty-four hours later they began a 7-day cold acclimation protocol (daily 90 min immersion in 10 °C water). On days one, four, and seven of cold acclimation, participants completed the same cycling test. Measurements of work completed, core and skin temperatures, heart rate, skin blood flow, perceived exertion, and thermal sensation were measured during each cycling test. Successful insulative cold acclimation was observed. Work produced during the baseline cycling test (220 ± 70 kJ) was greater (p immersions (195 ± 58, 197 ± 60, and 194 ± 62 kJ) despite similar ratings of perceived exertion during each test, suggesting that cold exposure impaired cycling performance. This impairment, however, was not attenuated over the cold acclimation period. Results suggest that insulative cold acclimation does not attenuate impairments in exercise performance that were observed following acute cold water immersion.

Caffeine administration at night during extended wakefulness effectively mitigates performance impairment but not subjective assessments of fatigue and sleepiness.

Science.gov (United States)

Paech, Gemma M; Banks, Siobhan; Pajcin, Maja; Grant, Crystal; Johnson, Kayla; Kamimori, Gary H; Vedova, Chris B Della

2016-06-01

The current study investigated the effects of repeated caffeine administration on performance and subjective reports of sleepiness and fatigue during 50h extended wakefulness. Twenty-four, non-smokers aged 22.5±2.9y (mean±SD) remained awake for two nights (50h) in a controlled laboratory environment. During this period, 200mg of caffeine or placebo gum was administered at 01:00, 03:00, 05:00 and 07:00 on both nights (total of 800mg/night). Neurobehavioral performance and subjective reports were assessed throughout the wake period. Caffeine improved performance compared to placebo, but did not affect overall ratings of subjective sleepiness and fatigue. Performance and sleepiness worsened with increasing time awake for both conditions. However, caffeine slowed performance impairments such that after 50h of wakefulness performance was better following caffeine administration compared to placebo. Caffeine also slowed the increase in subjective sleepiness and performance ratings, but only during the first night of wakefulness. After two nights of sleep deprivation, there was no difference in sleepiness ratings between the two conditions. These results demonstrate that strategic administration of caffeine effectively mitigates performance impairments associated with 50h wakefulness but does not improve overall subjective assessments of sleepiness, fatigue and performance. Results indicate that while performance impairment is alleviated, individuals may continue to report feelings of sleepiness. Individuals who use caffeine as a countermeasure in sustained operations may feel as though caffeine is not effective despite impairments in objective performance being largely mitigated. Copyright © 2016 Elsevier Inc. All rights reserved.

Validation of Taiwan Performance-Based Instrumental Activities of Daily Living (TPIADL), a Performance- Based Measurement of Instrumental Activities of Daily Living for Patients with Vascular Cognitive Impairment.

Science.gov (United States)

Chen, Hui-Mei; Lin, Hsiu-Fen; Huang, Mei-Feng; Chang, Chun-Wei; Yeh, Yi-Chun; Lo, Yi-Ching; Yen, Cheng-Fang; Chen, Cheng-Sheng

2016-01-01

Patients with cerebrovascular diseases often presented both cognitive and physical impairment. Disability in everyday functioning involving cognitive impairment among patients may be hard to completely rely on informants' reports, as their reports may be confounded with physical impairment. The aim of this study was to validate a performance-based measure of functional assessment, the Taiwan Performance-Based Instrumental Activities of Daily Living (TPIADL), for vascular cognitive impairment (VCI) by examining its psychometric properties and diagnostic accuracy. Ninety-seven patients with cerebrovascular diseases, including 30 with vascular dementia (VaD), 28 with mild cognitive impairment and 39 with no cognitive impairment, and 49 healthy control adults were recruited during study period. The TPIADL, as well as the Mini Mental State Examination (MMSE), Lawton-IADL and Barthel Index (BI), were performed. The internal consistency, convergent and criteria validity of the TPIADL were examined. Cronbach's alpha of the TPIADL test was 0.84. The TPIADL scores were significantly correlated with the Lawton IADL (r = -0.587, p cognitive domain of Lawton IADL (r = -0.663) than with physical domain of Lawton IADL (r = -0.541). The area under the relative operating characteristic curve was 0.888 (95% CI = 0.812-0.965) to differentiate VaD from other groups. The optimal cut-off point of the TPIADL for detecting VaD was 6/7, which gives a sensitivity of 73.3% and a specificity of 84.5%. The TPIADL is a brief and sensitive tool for the detection of IADL impairment in patients with VaD.

The effects of neural mobilization on cervical radiculopathy patients' pain, disability, ROM, and deep flexor endurance.

Science.gov (United States)

Kim, Dong-Gyu; Chung, Sin Ho; Jung, Ho Bal

2017-09-22

Cervical radiculopathy (CR) is a disease of the cervical spine and a space-occupying lesion that occurs because of pathological problems with cervical nerve roots. Nerve root injury to produce functional disability. The purpose of this study was to examine the effects of neural mobilization with manual cervical traction (NMCT) compared with manual cervical traction (MCT) on pain, functional disability, muscle endurance, and range of motion (ROM) in individuals with CR patients. A blinded randomized clinical trial was conducted. Thirty CR patients were divided into two groups - those who received NMCT and those who received MCT. The intervention was applied three times per week for eight weeks. It was measured in order to determine the pain and functional disability in patients with CR. The numeric pain rating scale (NPRS), neck disability index (NDI), ROM, and deep flexor endurance of patients were measured prior to the experiment, four weeks, and eight weeks after the experiment to compare the time points. A repeated-measures analysis of variance was used to compare differences within each group prior to the experiment. And Bonferroni test was performed to examine the significance of each time point. There were significant differences within each group prior to the intervention, four weeks after the intervention, and eight weeks after the intervention in NPRS, NDI, ROM, and deep flexor endurance (Ppain relief, recovery from neck disability, ROM, and deep flexor endurance for patients with CR.

Reliability and validity of the test of incremental respiratory endurance measures of inspiratory muscle performance in COPD.

Science.gov (United States)

Formiga, Magno F; Roach, Kathryn E; Vital, Isabel; Urdaneta, Gisel; Balestrini, Kira; Calderon-Candelario, Rafael A; Campos, Michael A; Cahalin, Lawrence P

2018-01-01

The Test of Incremental Respiratory Endurance (TIRE) provides a comprehensive assessment of inspiratory muscle performance by measuring maximal inspiratory pressure (MIP) over time. The integration of MIP over inspiratory duration (ID) provides the sustained maximal inspiratory pressure (SMIP). Evidence on the reliability and validity of these measurements in COPD is not currently available. Therefore, we assessed the reliability, responsiveness and construct validity of the TIRE measures of inspiratory muscle performance in subjects with COPD. Test-retest reliability, known-groups and convergent validity assessments were implemented simultaneously in 81 male subjects with mild to very severe COPD. TIRE measures were obtained using the portable PrO2 device, following standard guidelines. All TIRE measures were found to be highly reliable, with SMIP demonstrating the strongest test-retest reliability with a nearly perfect intraclass correlation coefficient (ICC) of 0.99, while MIP and ID clustered closely together behind SMIP with ICC values of about 0.97. Our findings also demonstrated known-groups validity of all TIRE measures, with SMIP and ID yielding larger effect sizes when compared to MIP in distinguishing between subjects of different COPD status. Finally, our analyses confirmed convergent validity for both SMIP and ID, but not MIP. The TIRE measures of MIP, SMIP and ID have excellent test-retest reliability and demonstrated known-groups validity in subjects with COPD. SMIP and ID also demonstrated evidence of moderate convergent validity and appear to be more stable measures in this patient population than the traditional MIP.

The Association Analysis between ACE and ACTN3 Genes Polymorphisms and Endurance Capacity in Young Cross-Country Skiers: Longitudinal Study

Directory of Open Access Journals (Sweden)

Agnes Mägi, Eve Unt, Ele Prans, Liina Raus, Jaan Eha, Alar Veraksitš, Külli Kingo, Sulev Kõks

2016-06-01

Full Text Available Endurance performance depends on the integration of several phenotypic traits influenced by multiple environmental and genetic factors. Objectives of the study were: (1 to examine the genotypic frequencies of the ACE I/D, ACTN3 R577X polymorphisms and endurance performance-related phenotypes, (2 to evaluate the dynamics of endurance performance parameters during a 5-year period in relation to ACE I/D and ACTN3 R577X genotypes in Estonian young skiers. Determination of VO2peak was performed in 58 skiers aged 15-19 years (41 males, 17 females during a 5-year period. The control group consisted of 322 healthy non-athletic subjects (145 males, 177 females. The study groups were genotyped for the ACE I/D and ACTN3 R577X variants. Frequencies of the ACE ID and ACTN3 RR genotypes were significantly higher (p = 0.047 and p = 0.003, respectively and the RX genotype was lower (p = 0.008 in young male skiers compared with controls. A significant relationship was found between change (Δ of training volume and ΔVO2peak (mL·kg-1·min-1 (r = 0.475, p = 0.002. No significant main effect was detected between VO2peak (mL·kg-1·min-1 dynamics (comparison with the previous age group data and ACE I/D and ACTN3 R577X genotypes interactions (F = 0.571, p = 0.770 and F = 0.650 and p = 0.705, respectively in all young skiers. Study results indicated a significantly higher frequency of the ACE ID and ACTN3 RR genotypes among Estonian young male skiers compared with the male control group. Significant genotype-related differences in dynamics of VO2peak during a 5-year period were not found. In the future, longitudinal research including different gene variants may contribute to a better understanding of the nature of endurance performance.

Learning trajectories for speech motor performance in children with specific language impairment.

Science.gov (United States)

Richtsmeier, Peter T; Goffman, Lisa

2015-01-01

Children with specific language impairment (SLI) often perform below expected levels, including on tests of motor skill and in learning tasks, particularly procedural learning. In this experiment we examined the possibility that children with SLI might also have a motor learning deficit. Twelve children with SLI and thirteen children with typical development (TD) produced complex nonwords in an imitation task. Productions were collected across three blocks, with the first and second blocks on the same day and the third block one week later. Children's lip movements while producing the nonwords were recorded using an Optotrak camera system. Movements were then analyzed for production duration and stability. Movement analyses indicated that both groups of children produced shorter productions in later blocks (corroborated by an acoustic analysis), and the rate of change was comparable for the TD and SLI groups. A nonsignificant trend for more stable productions was also observed in both groups. SLI is regularly accompanied by a motor deficit, and this study does not dispute that. However, children with SLI learned to make more efficient productions at a rate similar to their peers with TD, revealing some modification of the motor deficit associated with SLI. The reader will learn about deficits commonly associated with specific language impairment (SLI) that often occur alongside the hallmark language deficit. The authors present an experiment showing that children with SLI improved speech motor performance at a similar rate compared to typically developing children. The implication is that speech motor learning is not impaired in children with SLI. Copyright © 2015 Elsevier Inc. All rights reserved.

Neck muscle endurance and head posture: A comparison between adolescents with and without neck pain.

Science.gov (United States)

Oliveira, Ana Carolina; Silva, Anabela G

2016-04-01

The main aims of this study were to compare the neck flexor and extensor endurance and forward head posture between adolescents with and without neck pain. The secondary aims were to explore potential associations between muscles endurance, head posture and neck pain characteristics and to assess intra-rater reliability of the measurements used. Adolescents with neck pain (n = 35) and age-matched asymptomatic adolescents (n = 35) had their forward head posture, neck flexor endurance and neck extensor endurance measured using clinical tests. Intra-rater reliability was also assessed. Forward head posture and neck flexor and extensor endurance tests showed moderate to almost perfect intra-rater reliability (ICC between 0.58 and 0.88). Adolescents with neck pain showed significantly less forward head posture (neck pain = 46.62 ± 4.92; asymptomatic = 44.18°± 3.64°, p > 0.05) and less neck flexor (neck pain = 24.50 ± 23.03s; asymptomatic = 35.89 ± 21.53s, p > 0.05) and extensor endurance (neck pain = 12.6.64 ± 77.94s; asymptomatic = 168.66 ± 74.77s, p > 0.05) than asymptomatic adolescents. Results suggest that changes in posture and neck muscle endurance are a feature of adolescents with neck pain. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mental Fatigue Impairs Soccer-Specific Physical and Technical Performance.

Science.gov (United States)

Smith, Mitchell R; Coutts, Aaron J; Merlini, Michele; Deprez, Dieter; Lenoir, Matthieu; Marcora, Samuele M

2016-02-01

To investigate the effects of mental fatigue on soccer-specific physical and technical performance. This investigation consisted of two separate studies. Study 1 assessed the soccer-specific physical performance of 12 moderately trained soccer players using the Yo-Yo Intermittent Recovery Test, Level 1 (Yo-Yo IR1). Study 2 assessed the soccer-specific technical performance of 14 experienced soccer players using the Loughborough Soccer Passing and Shooting Tests (LSPT, LSST). Each test was performed on two occasions and preceded, in a randomized, counterbalanced order, by 30 min of the Stroop task (mentally fatiguing treatment) or 30 min of reading magazines (control treatment). Subjective ratings of mental fatigue were measured before and after treatment, and mental effort and motivation were measured after treatment. Distance run, heart rate, and ratings of perceived exertion were recorded during the Yo-Yo IR1. LSPT performance time was calculated as original time plus penalty time. LSST performance was assessed using shot speed, shot accuracy, and shot sequence time. Subjective ratings of mental fatigue and effort were higher after the Stroop task in both studies (P motivation was similar between conditions. This mental fatigue significantly reduced running distance in the Yo-Yo IR1 (P performance time were not different between conditions; however, penalty time significantly increased in the mental fatigue condition (P = 0.015). Mental fatigue also impaired shot speed (P = 0.024) and accuracy (P performance.

The Effects of Mental Fatigue on Physical Performance: A Systematic Review.

Science.gov (United States)

Van Cutsem, Jeroen; Marcora, Samuele; De Pauw, Kevin; Bailey, Stephen; Meeusen, Romain; Roelands, Bart

2017-08-01

Mental fatigue is a psychobiological state caused by prolonged periods of demanding cognitive activity. It has recently been suggested that mental fatigue can affect physical performance. Our objective was to evaluate the literature on impairment of physical performance due to mental fatigue and to create an overview of the potential factors underlying this effect. Two electronic databases, PubMed and Web of Science (until 28 April 2016), were searched for studies designed to test whether mental fatigue influenced performance of a physical task or influenced physiological and/or perceptual responses during the physical task. Studies using short (mental fatigue. Maximal strength, power, and anaerobic work were not affected by mental fatigue. The duration and intensity of the physical task appear to be important factors in the decrease in physical performance due to mental fatigue. The most important factor responsible for the negative impact of mental fatigue on endurance performance is a higher perceived exertion.

Insulin signaling in skeletal muscle of HIV‐infected patients in response to endurance and strength training

DEFF Research Database (Denmark)

Broholm, Christa; Mathur, Neha; Hvid, Thine

2013-01-01

. Euglycemic-hyperinsulinemic clamps with muscle biopsies were performed before and after the training interventions. Fifteen age- and body mass index (BMI)-matched HIV-negative men served as a sedentary baseline group. Phosphorylation and total protein expression of insulin signaling molecules as well...... hexokinase II (HKII) protein. HIV-infected patients with lipodystrophy have decreased insulin-stimulated glucose uptake in skeletal muscle and defects in insulin-stimulated phosphorylation of Akt(thr308). Endurance and strength training increase insulin-stimulated glucose uptake in these patients......Human immunodeficiency virus (HIV)-infected patients with lipodystrophy have decreased insulin-stimulated glucose uptake. Both endurance and resistance training improve insulin-stimulated glucose uptake in skeletal muscle of HIV-infected patients, but the mechanisms are unknown. This study aims...

Comparison of Brain-Derived Neurotrophic Factor (BDNF and Insulin-like Growth Factor 1 (IGF-1 Responses to Different Endurance Training Intensities in Runner Men

Directory of Open Access Journals (Sweden)

M. Habibian

2017-04-01

Full Text Available Aims: Blood neurotrophins, such as Brain-Derived Neurotrophic Factor (BDNF and Insulin-like Growth Factor 1 (IGF-1, mediate exercise- induced health benefits in humans. The purpose of this study was to compare the response of BDNF and IGF-1 to different endurance training intensities in runner men. Materials & Methods: In this semi-experimental study with pre-test-posttest design in 2015, 10 people of male runners from Gorgan were selected through purposeful and accessible sampling. The endurance training protocol was 6 km running with moderate (70-75% of heart rate reserve or severe (80-85% of heart rate reserve intensity, which was performed within a week's interval. Fasting blood samples were collected before and immediately after both acute training sessions and serum levels of BDNF and IGF-1 were measured by ELISA and radioimmunoassay enzyme. Data were analyzed by SPSS 20 software using independent t-test and paired t-test. Findings: Both acute endurance training significantly increased serum levels of BDNF and IGF-1 in runners, but high intensity endurance exercises increased BDNF levels in comparison with moderate intensity (p0.05. Conclusion: Serum BDNF response in endurance athletes is affected by the intensity of exercise, so that the effect of high intensity endurance training on BDNF levels is greater than moderate intensity exercise, but the response of IGF-1 to acute endurance training is independent of the intensity of exercise.

The Effect of Acute Endurance Exercise on Plasma Myostastin in Healthy Elderly Men

Directory of Open Access Journals (Sweden)

Meysam Gholamali

2015-04-01

Conclusion Plasma Myostatin decreased significantly in the response to endurance exercise, in healthy elderly men. Presumably, according to the results of this study, prescription of endurance exercise may decrease Myostatin and subsequently sarcopenia in elderly people.

Neurocognitive impairment in the deficit subtype of schizophrenia.

Science.gov (United States)

Fervaha, Gagan; Agid, Ofer; Foussias, George; Siddiqui, Ishraq; Takeuchi, Hiroyoshi; Remington, Gary

2016-08-01

Schizophrenia is a heterogeneous disorder characterized by numerous diverse signs and symptoms. Individuals with prominent, persistent, and idiopathic negative symptoms are thought to encompass a distinct subtype of schizophrenia. Previous work, including studies involving neuropsychological evaluations, has supported this position. The present study sought to further examine whether deficit patients are cognitively distinct from non-deficit patients with schizophrenia. A comprehensive neurocognitive battery including tests of verbal memory, vigilance, processing speed, reasoning, and working memory was administered to 657 patients with schizophrenia. Of these, 144 (22 %) patients were classified as deficit patients using a proxy identification method based on severity, persistence over time, and possible secondary sources (e.g., depression) of negative symptoms. Deficit patients with schizophrenia performed worse on all tests of cognition relative to non-deficit patients. These patients were characterized by a generalized cognitive impairment on the order of about 0.4 standard deviations below that of non-deficit patients. However, when comparing deficit patients to non-deficit patients who also present with negative symptoms, albeit not enduring or primary, no group differences in cognitive performance were found. Furthermore, a discriminant function analysis classifying patients into deficit/non-deficit groups based on cognitive scores demonstrated only 62.3 % accuracy, meaning over one-third of individuals were misclassified. The deficit subtype of schizophrenia is not markedly distinct from non-deficit schizophrenia in terms of neurocognitive performance. While deficit patients tend to have poorer performance on cognitive tests, the magnitude of this effect is relatively modest, translating to over 70 % overlap in scores between groups.