Limits to human performance caused by muscle fatigue

2004 ◽  
pp. 7-10
Author(s):  
David Allen ◽  
Jan Lännergren ◽  
Håkan Westerblad
Keyword(s):  
Muscle Fatigue ◽  
Human Performance

The Role of O2 Supply in Muscle Fatigue

2002 ◽  
Vol 27 (1) ◽  
pp. 56-69 ◽  
Author(s):  
Russell T. Hepple
Keyword(s):  
Blood Flow ◽  
Muscle Fatigue ◽  
Human Performance ◽  
Aerobic Performance ◽  
Cellular Respiration ◽  
Reduction In Force ◽  
O2 Supply ◽  
By Products

It is well established that altering O2 delivery to contracting skeletal muscle affects human performance. In this respect, a reduced O2 supply (e.g., hypoxia) increases the rate of muscle fatigue, whereas increasing O2 supply (e.g., hyperoxia) reduces the rate of fatigue. Interestingly, the faster onset of fatigue in moderate hypoxia does not appear to be a consequence of mitochondrial O2 limitation because these effects occur at submaximal rates of O2 consumption for these conditions and at O2 tensions well above that which impairs mitochondrial O2 uptake in vitro. Alterations in O2 supply modulate the regulation of cellular respiration and may affect the onset of impaired Ca2+ handling with fatigue. Specifically, changes in O2 supply alter the coupling between phosphocreatine hydrolysis and O2 uptake in contracting muscles, which by determining the rate of inorganic phosphate (Pi) accumulation may affect Ca2+ release. Partial ischemia differs somewhat in that the reduction in force could be due to reduced O2 supply and/or impaired removal of metabolic by-products secondary to insufficient blood flow. Nonetheless, recent evidence shows a parallel decline and restoration of force with alterations in O2 supply but not blood flow alone during submaximal contractions. Furthermore, the causes of fatigue are similar when O2 is plentiful and when it is reduced. Key words: muscular contractions, aerobic performance, hypoxia, hyperoxia, muscle bioenergetic

scholarly journals Sex differences in muscle fatigue following isokinetic muscle contractions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Miguel Gomes ◽  
Paulo Santos ◽  
Paulo Correia ◽  
Pedro Pezarat-Correia ◽  
Goncalo V. Mendonca
Keyword(s):  
Sex Differences ◽  
Muscle Fatigue ◽  
Human Performance ◽  
Knee Extension ◽  
Muscle Contractions ◽  
Limiting Factor ◽  
Maximal Voluntary Isometric Contraction ◽  
Isokinetic Exercise ◽  
Isokinetic Contractions ◽  
The Impact

AbstractMuscle fatigue is a limiting factor of human performance. It is unclear whether sex-based differences in fatigability exist during dynamic exercise of varying velocities of contraction. We aimed at exploring sex differences in muscle fatigue elicited by maximal isokinetic muscle contractions performed at different angular velocities. Twenty-six healthy participants (13 men: 23.2 ± 1.5; 13 women: 21.9 ± 3.0 years) were tested for concentric knee-extension at slow, moderate and fast angular isokinetic velocity (60, 180 and 300º.s−1, respectively), on non-consecutive days. The impact of sex on fatigue resistance and consecutive recovery for each isokinetic condition was explored by calculating the percent change in maximal voluntary isometric contraction (MVIC) and in rate of torque development (RTD), from pre- to post-isokinetic exercise (30 repetitions). The isokinetic fatigue index was also determined. No sex differences were obtained in response to isokinetic contractions completed at 60º.s−1. After performing muscle contractions at 300º.s−1, women had a significantly greater loss in MVIC than men (− 18.4 ± 5.5 vs. − 12.9 ± 3.8%; p = 0.009) and larger decreases in work output during isokinetic exercise (− 34.2 ± 8.9 vs − 27.5 ± 10.6%; p = 0.017). Recovery of initial MVIC strength was greater for women post-exercise at 180º.s−1 (15.6 ± 4.1% vs. 6.7 ± 9.5; p = 0.003). No differences were found between sexes in any condition for RTD from pre- to post-fatigue. These results suggest the presence of a sexually dimorphic fatigability in response to dynamic (isokinetic) contractions favouring men at higher absolute velocities of contraction.

Floor Composition Affects Performance and Muscle Fatigue Following a Basketball Task

2000 ◽  
Vol 16 (2) ◽  
pp. 157-168 ◽  
Author(s):  
Jefferson W. Streepey ◽  
M. Melissa Gross ◽  
Bernard J. Martin ◽  
Sundravalli Sudarsan ◽  
Catherine M. Schiller
Keyword(s):  
Muscle Fatigue ◽  
Human Performance ◽  
Knee Extensor ◽  
Electromyographic Activity ◽  
Jump Height ◽  
Basketball Players ◽  
Wood Floor ◽  
Before And After ◽  
Voluntary Contractions ◽  
The Relationship

The relationship between playing surface and muscle fatigue was examined in 22 male subjects performing a simulated basketball task on a conventional wood floor and less stiff composite floor. Force and electromyographic activity (EMG) were measured during maximum and submaximum (10% of maximum) voluntary contractions of knee extensor and ankle plantarflexor muscles before and after completion of the simulated basketball task. Jump height was evaluated during the task, and perceived fatigue was assessed at the end of the task. Although not all subjects jumped significantly higher on the composite floor compared to the wood floor. competitive basketball players showed a significant improvement in jump height (3.4 cm. 6%) when jumping on the composite floor. Perceived fatigue was significantly lower for the composite floor (21.7%) than the wood floor (30.2%). The objective measures indicated the occurrence of fatigue; however, force and EMG magnitudes obtained during maximum exertions were not sensitive lo floor types. Post-task increase in EMG magnitude indicated a significant fatigue effect for the soleus muscle on the wood floor only. These findings suggest that the composite floor may benefit human performance without increasing fatigue during basketball-related activities.

scholarly journals Sex Differences in Muscle Fatigue Following Isokinetic Muscle Contractions

2020 ◽  
Author(s):  
Miguel Gomes ◽  
Paulo Santos ◽  
Paulo Correia ◽  
Pedro Pezarat-Correia ◽  
Goncalo V. Mendonca
Keyword(s):  
Sex Differences ◽  
Muscle Fatigue ◽  
Human Performance ◽  
Knee Extension ◽  
Muscle Contractions ◽  
Limiting Factor ◽  
Maximal Voluntary Isometric Contraction ◽  
Isokinetic Exercise ◽  
Isokinetic Contractions ◽  
The Impact

Abstract Muscle fatigue is a limiting factor of human performance. It is unclear whether sex-based differences in fatigability exist during dynamic exercise of varying velocities of contraction. We aimed at exploring sex differences in muscle fatigue elicited by maximal isokinetic muscle contractions performed at different angular velocities. Twenty-six healthy participants (13 men: 23.2 ± 1.5; 13 women: 21.9 ± 3.0 years) were tested for knee-extension at slow, moderate and fast angular velocity (60, 180 and 300º.s-1, respectively). The impact of sex on fatigue resistance and consecutive recovery for each isokinetic condition was explored by calculating the percent change in maximal voluntary isometric contraction (MVIC) and in rate of torque development (RTD), from pre- to post-isokinetic exercise. The isokinetic fatigue index was also determined. No sex differences were obtained in response to isokinetic contractions completed at 60º.s-1. After performing muscle contractions at 300º.s-1, women had a significantly greater loss in MVIC than men (-18.4 ± 5.5 vs. -12.9 ± 3.8%; p = 0.009) and larger decreases in work output during isokinetic exercise (-34.2 ± 8.9 vs -27.5 ± 10.6 %; p = 0.017). Recovery of initial MVIC strength was greater for women post-exercise at 180º.s-1 (6.7 ± 9.5 vs. 15.6 ± 4.1%; p = 0.003). No differences were found between sexes in any condition for RTD from pre- to post- fatigue. These results suggest the presence of a sexually dimorphic fatigability in response to dynamic (isokinetic) contractions favouring men at higher velocities of contraction.

The limits of human performance

2008 ◽  
Vol 44 ◽  
pp. 11-26 ◽  
Author(s):  
Ralph Beneke ◽  
Dieter Böning
Keyword(s):  
Human Performance ◽  
Safety Margin ◽  
Afferent Input ◽  
Metabolic Energy ◽  
Human Organism ◽  
Mechanical Resistance ◽  
As Doping ◽  
Gene And Protein Expression ◽  
Underlying Mechanisms ◽  
Biochemical Research

Human performance, defined by mechanical resistance and distance per time, includes human, task and environmental factors, all interrelated. It requires metabolic energy provided by anaerobic and aerobic metabolic energy sources. These sources have specific limitations in the capacity and rate to provide re-phosphorylation energy, which determines individual ratios of aerobic and anaerobic metabolic power and their sustainability. In healthy athletes, limits to provide and utilize metabolic energy are multifactorial, carefully matched and include a safety margin imposed in order to protect the integrity of the human organism under maximal effort. Perception of afferent input associated with effort leads to conscious or unconscious decisions to modulate or terminate performance; however, the underlying mechanisms of cerebral control are not fully understood. The idea to move borders of performance with the help of biochemicals is two millennia old. Biochemical findings resulted in highly effective substances widely used to increase performance in daily life, during preparation for sport events and during competition, but many of them must be considered as doping and therefore illegal. Supplements and food have ergogenic potential; however, numerous concepts are controversially discussed with respect to legality and particularly evidence in terms of usefulness and risks. The effect of evidence-based nutritional strategies on adaptations in terms of gene and protein expression that occur in skeletal muscle during and after exercise training sessions is widely unknown. Biochemical research is essential for better understanding of the basic mechanisms causing fatigue and the regulation of the dynamic adaptation to physical and mental training.

1880: Assessment of Basic Human Performance Resources Predicts Performance of Ureterorenoscopy in Human Cadavers

2004 ◽  
Vol 171 (4S) ◽  
pp. 496-497
Author(s):  
Edward D. Matsumoto ◽  
George V. Kondraske ◽  
Lucas Jacomides ◽  
Kenneth Ogan ◽  
Margaret S. Pearle ◽  
...  
Keyword(s):  
Human Performance ◽  
Human Cadavers

MUSCLE FATIGUE IN A STANDING HEEL-RISE TEST

1998 ◽  
Vol 30 (2) ◽  
pp. 67-72 ◽  
Author(s):  
Ulla Svantesson, Ulrika Österber
Keyword(s):  
Muscle Fatigue

Short Stress State Questionnaire

2015 ◽  
Vol 31 (1) ◽  
pp. 20-30 ◽  
Author(s):  
William S. Helton ◽  
Katharina Näswall
Keyword(s):  
Stress State ◽  
Factor Structure ◽  
Human Performance ◽  
Self Report ◽  
Confirmatory Factor ◽  
Stress States ◽  
Related Stress ◽  
Using Data ◽  
Task Conditions ◽  
Multiple Samples

Conscious appraisals of stress, or stress states, are an important aspect of human performance. This article presents evidence supporting the validity and measurement characteristics of a short multidimensional self-report measure of stress state, the Short Stress State Questionnaire (SSSQ; Helton, 2004 ). The SSSQ measures task engagement, distress, and worry. A confirmatory factor analysis of the SSSQ using data pooled from multiple samples suggests the SSSQ does have a three factor structure and post-task changes are not due to changes in factor structure, but to mean level changes (state changes). In addition, the SSSQ demonstrates sensitivity to task stressors in line with hypotheses. Different task conditions elicited unique patterns of stress state on the three factors of the SSSQ in line with prior predictions. The 24-item SSSQ is a valid measure of stress state which may be useful to researchers interested in conscious appraisals of task-related stress.

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