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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Between the 1960s and the 1980s there has been an increase in the Journal of Motor Behavior (JMB) of neuromuscular theories of control, of continuous records showing amplitude or force over time, and of electromyograms (EMGs). Investigations of the advance programming of complex movements have also increased. There has been a decrease in paced manual tracking, in movements along a fixed path, and in studies of proprioception. Investigations of transfer or interference, of motor learning, and of muscular fatigue have also decreased. Some investigators still appear to be unaware of the contraction bias or regression effect.
J Mot Behav 1988 Mar
PMID:The journal of motor behavior in the 1960s and the 1980s. 1507 34

Thirty male subjects, 20 of whom were self-classified left-handers and 10 right-handers, were tested on a grip-strength task and a handwriting task with each hand, both under normal conditions and in a situation of induced experimental fatigue. On the basis of questionnaire scores, the left-handers were sub-divided into two groups comprising the 10 most left-handed and the 10 least left-handed subjects. The test of grip strength showed a small but significant deterioration in performance of both hands from fatigue. With the handwriting task, a similar significantly adverse effect of fatigue was recorded for all groups as well as a large significant difference in performance between the preferred and nonpreferred hands under normal conditions, which decreased under fatigue. An explanation of these differential effects is discussed in terms of the greater efficiency of the preferred hand in the highly developed skill of handwriting.
J Mot Behav 1989 Jun
PMID:Skill, strength, handedness, and fatigue. 1513 40

The concept of motion variability is discussed and a normalized measure for its quantification is introduced. An example demonstrates that this new measure constitutes a global indicator of the current state of a motor learning process. The causes of motion variations are briefly discussed. They include initial perturbations of the skeletal, muscular, and neural systems as well as perturbations due to incremental changes, during motion execution, of external forces, muscular parameters (fatigue), afferent sensory inputs, and of the motor programs controlling the execution of the motion.
J Mot Behav 1986 Mar
PMID:Motion variability--its definition, quantification, and origin. 1513 82

Two experiments examined the effects of preliminary exercise on performance and learning of the Fitts' reciprocal tapping task. In the first experiment preliminary exercise was performed with either the preferred or nonpreferred arm. The tapping task was completed with the preferred by both groups. Low levels of preliminary exercise resulted in heightened performance for both groups, but higher levels resulted in a decrement for the group using the preferred arm. An arousal-plus-fatigue hypothesis can explain the results. A subsequent post-test without preliminary exercise showed no difference between the groups, indicating an effect on performance and not learning. In the second experiment preliminary exercise was provided by treadmill running to exhaustion. Again, a facilitatory effect of exercise was demonstrated on tapping performance even after exhaustive levels of running.
J Mot Behav 1979 Jan
PMID:Warm- and fatigue in skill acquisition and performance. 1518 75

Surface EMG enabled fractionation of a simple hand grip total reaction time into peripheral and central processing components (motor time and premotor time respectively). Changes in reaction time components were investigated in 12 female intercollegiate swimmers (bilateral athletes) and 12 female intercollegiate tennis players (unilateral athletes) following a 48% strength decrement induced by serial maximal voluntary isometric contractions (5 sec in duration). Despite significantly greater strength in the dominant arm than in the nondominant arm, there was no difference in fatigue effects between arms. Fatigue increased the premotor component of reaction time significantly, and indirectly the total reaction time, but the motor time remained essentially constant regardless of the type of previous athletic training. This indicated that fatigue impaired central nervous system or myoneural-junction operations rather than the intramuscular ability to initiate force.
J Mot Behav 1978 Sep
PMID:Effects of fatigue and laterality on fractionated reaction time. 1518 79

The effects of varying fatigue levels on reaction-time components were determined for 20 young, adult males. Each subject squeezed a hand-gripping device until strength decrements of 20, 40, or 60% were recorded; then the subject released his tension and then reacted to an auditory stimulus by gripping as quickly and forcefully as possible. Testing was also conducted under a nonfatigued state, and every subject was tested under all conditions. Total reaction time was divided into (a) a promoter component, the time from the stimulus to an alteration in the EMG of the finger flexors, and (b) a motor component, the time from the change in the EMG to the first sign of tension uptake. Analyses of variance failed to reveal any alterations in either reaction time or promoter time; however, there was a significant (p < .05) elongation of motor time when the muscle was fatigued, with motor time tending to increase linearly as fatigue increased. The results suggest that localized fatigue of this nature is primarily of peripheral (muscular) origin.
J Mot Behav 1978 Sep
PMID:Effects of variable fatigue levels on reaction-time components. 1518 83

The is study examined the effects of 24 wk. of resistance training on mood in healthy but sedentary older adults. 28 participants performed resistance training 3 times per week for 24 weeks. No significant differences were found in mood scores between high and variable resistance groups, and there were no significant interactions between resistance and sex or intervention, or among all three factors. For pooled data, significant improvement was found on measures of Confusion, Tension, Anger, and Total Mood Scores, although not for scores for Fatigue, Vigor, and Depression. Sex differences were found on some subscales, but no significant interactions between sex and resistance training. These findings support the effectiveness of resistance training in improving mood in healthy older adults, although further study is needed to control for effect size, as well as cohort, social, and attentional effects.
Percept Mot Skills 2004 Jun
PMID:Resistance training is associated with improved mood in healthy older adults. 1520 11

The purpose of this study was to assess whether the platform foot-pedal position affected maximal oxygen intake (VO2 max) at the highest aerobic demand in cycling. 21 inexperienced cyclists completed two exercise tests, one in the "normal" platform foot-pedal position and the other in the Biopedal forefoot varus foot-pedal position, cycling on an exercise ergometer. The time between tests ranged from 1 to 3 days depending on the subject's reported fatigue and muscle soreness. The highest aerobic demand was the subject's VO2 max at the point just below the subject's anaerobic threshold. A one-way analysis of variance indicated that the subject's VO2 max performance was similar between the foot-pedal positions. These results did not support the assumption that the Biopedal forefoot varus foot-pedal position would enable the cyclist to be more efficient at the highest aerobic demand when compared to a standard platform foot-pedal position.
Percept Mot Skills 2004 Jun
PMID:Effects of foot-pedal positions by inexperienced cyclists at the highest aerobic level. 1520 23

This study investigated the possible relationship between recovery-stress state and competition results in sprinters and jumpers. The Recovery-Stress Questionnaire for Athletes of Kellmann and Kallus was used. The subjects were tested one day before the Estonian Indoor Championships (n = 10; 4 men and 6 women) and Outdoor Championships (n= 11; 4 men and 7 women). The competition results were measured as International Amateur Athletic Federation points. Scores for Fatigue (r = -.74) and Emotional Stress (r =-.79) from the subscales were correlated with IAAF points during Indoor Championships. Competition results from the Outdoor Championships were correlated with scores on the Somatic Complaints (r =-.70) and General Well-being (r = .63) subscales. Individual analysis suggests a possible relationship between the recovery-stress state and performance in competition which should be investigated further.
Percept Mot Skills 2004 Aug
PMID:Relationships between recovery-stress state and performance in sprinters and jumpers. 1544 23

Visual analogue scale has been shown to reflect subjective feelings but rarely has it been used for musculoskeletal fatigue so in the present study VAS ratings were used to quantify musculoskeletal fatigue. A total of 20 students underwent a fatigue protocol (M age=21.3 yr., SD= 1.0). A series of randomized external loads at 0, 5, 10, 15, 25, 35, and 50% of the maximum voluntary contraction was generated by the BTE Primus and applied at the distal end of the dominant arm, which was sustained at the 90 degrees forward flexion position. After 60 sec. of force exertion for each loading, the subject marked the scale to reflect their extent of fatigue at the shoulder muscle. Analysis showed fatigue scores were significantly correlated with the percentages of maximum load applied (r =.73, p < or = .01). The correlation between higher external loads (25-50% maximum load) and fatigue scores was .57 (p < or = .01) and that for lower external loads (0-15% maximum load) was .44 (p < or = .01). The validity of using a visual analogue scale as a measure of musculoskeletal fatigue requires further study, particularly for a low load.
Percept Mot Skills 2004 Aug
PMID:Visual analogue scale correlates of musculoskeletal fatigue. 1544 51


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