摘要:

Fluctuations during the initial segment of torque recordings with isokinetic dynamometers have been attributed to impact artifacts and the relationship of contracting muscles to this period is not well understood. The purpose of this study was to investigate patterns of muscle activity during the period of isokinetic dynamometer compliance. Nine female track athletes were tested in extension and flexion at 1.75 rad.s‐1(100 deg.s‐1and 6.98 rad.s‐1(400 deg.s‐1) on an isokinetic dynamometer. Subjects performed 5 trials of extension of the leg immediately followed by flexion. Data were collected from two sets of surface electrodes attached to the biceps femoris and vastus lateralis muscles of the right thigh of each subject simultaneous with the torque and joint position signals from the dynamometer. In the first part of the analysis, a strong relationship was shown to exist between the IEMG slope variables and the measured torque output at both speeds of movement for extension and flexion. The proportion of variances accounted for in predicting the torque variables by the IEMG slope parameters ranged from 51 to 95%. This demonstrated that the activation of the muscle paralleled the torque changes in the limb‐lever system for different speeds of movement. The temporal relationship between the IEMG slope parameters and the generated torque was also examined. In the conditions where an overshoot torque occurred, the rate of change of the IEMG curve dropped off rapidly, indicating that changes in the pattern of muscular activation accompanied the initial spike in the torque trace. The data suggest that the sudden braking and releasing of the dynamometer speed control system result in considerable adjustments by agonist muscles which occur in synchrony with the peak and trough of the torque curve. If these changes in activation are accompanied by changes in muscle tension, then rehabilitative protocols, during which an overshoot torque occurs, may have to be modified.

ISSN:1057-8315    

DOI:10.1080/15438629009511892

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

The purpose of this study was to establish the validity, reliability and objectivity of an intermittent cycling test of anaerobic power and endurance for ice hockey players. The intermittent cycling test consisted of 6 repetitions, each 15s in duration with each repetition separated by a 15s recovery interval resulting in a total work time of 90s and a work to recovery ratio of 1:1. Four groups of subjects completed laboratory and on‐ice anaerobic tests. The groups consisted of 17 varsity hockey players, 11 varsity and junior varsity players, 14 junior varsity players, and 15 physical education students. All four groups completed the intermittent cycling test. The three hockey groups were assessed on a repeat sprint skate test. Physiological and metabolic data were also collected on group 2 to investigate the aerobic and anaerobic intensity of the test. The intermittent cycling test discriminated among the varsity, junior varsity, and non‐varsity players, thereby establishing construct validity. Peak power (watts/kg) correlated significantly (r=–.87) with on‐ice skating speed while mean power (watts/kg) correlated significantly (r=–.78) with the anaerobic endurance index of the repeat sprint skate test. Hence, criterion related validity was established. Intraclass correlation coefficients of. 93 and. 99 attested to the reliability and objectivity of the intermittent cycling test. The test taxed both the aerobic and anaerobic sytems. Peak VO2during the test was 97.8% of VO2maxwith a post‐exercise lactate concentration of 13.3 mmol/1. The drop‐off in power output between repetitions 1 and 6 was 28% for the varsity players, 35% for the junior varsity hockey players, and 43% for the physical education students. It was concluded mat the intermittent cycling test is a valid, reliable, and objective test of the anaerobic endurance of ice hockey players.

ISSN:1057-8315    

DOI:10.1080/15438629009511893

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

Longitudinal monitoring of young sportspersons (50 males and 35 females) was used to verify the accuracy of two methods (Bayley, 1959; Prokopec, 1979) of adult body height prediction based on a knowledge of the skeletal age of the subjects. The methods are also compared with prediction based on calendar age. The mean difference in prediction was 2% of adult body height using the Bayley (1959) method and 1.5% using the method of Prokopecet al.(1979), similarly for males and females. The categories of deviations 0‐2 and 2‐5 cm included 96% of males and 100% of females according to the Prokopec method, whereas in the case of Bayley's the figures were 80% and 100% respectively. Thus the percentile growth graph of Prokopecet al.seems more suitable, particularly in the case of above‐average height.

ISSN:1057-8315    

DOI:10.1080/15438629009511894

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

Variability in the response to“post‐coronary”; exercise rehabilitation has previously been attributed to the age of the patient, their date of entry to the program relative to the acute incident, and the liability of the participant to anginal pain. We examined the relative importance of these three variables in a sample of thirty‐five patients seen two to 12 months after a well‐defined myocardial infarction. Cardiovascular responses of the patients at entry to the program and after six months and one year of intensive endurance training were evaluated by a progressive submaximal cycle ergometer test. Cardiac output was determined by a carbon dioxide rebreathing method. Training responses of the eight subgroups of patients was remarkably uniform; over the 12 months of observation, all showed an increase of stroke volume and a decrease of heart rate during submaximal work. The corresponding increase of predicted maximal oxygen intake ranged from 13 to 21%. We conclude that the variable cardiac response to training cannot be attributed to the factors that we examined. Other influences, such as cardiovascular status before infarction and the length of the training program may be involved.

ISSN:1057-8315    

DOI:10.1080/15438629009511895

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

Conditioned runners may be able to endure higher levels of stress and pain during racing due to the presence of elevated endogenous opiates. To test this hypothesis, intravenous naloxone 10 mg or saline was administered in a repeated measures randomized, double‐blind protocol to 15 male runners. About 20 minutes after the injection, the subjects ran a 400 meter race, with the elapsed time being recorded. Pre‐and post‐run mood and post‐run global pain status were measured. Contrary to the hypothesis, naloxone had no statistically significant effect on mean race time, mean pre‐to post‐race mood, or upon a post‐race global pain rating when compared with saline; a trend in the analysis (p = 0.12) did suggest that naloxone injection was associated with faster run times. Three runners showed a marked improvement in racing time following naloxone, suggesting that some athletes may gain advantage by having blocked endorphins during maximal performances.

ISSN:1057-8315    

DOI:10.1080/15438629009511896

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

The partial curl‐up has been recommended as a better test of abdominal muscular endurance, replacing the one‐minute speed sit‐up with anchored feet. The curl‐up begins from a supine position, with the knees bent at 140°and the feet unsupported. The subject curls up in a controlled fashion until the fingertips are just able to touch the patellae; then, the trunk is slowly lowered until the head and shoulders touch the mat. This report presents age and gender standards for the partial curl‐up derived from the testing of 2178 males and 672 females.The partial curl‐up appears to be a safe protocol, with relatively few individuals experiencing dizziness, headache, nausea, neck pain or back discomfort. Average scores for males are higher than for females and scores diminish dramatically with age. Among men 60‐69 and women 50‐59, approximately 20% are unable to perform one curl‐up.Correlations between curl‐up performance and age, stature, body weight, BMI, girths, body fat, trunk flexibility, aerobic fitness, upper body strength and muscular endurance were significant (p<0.0001), but accounted for less than 16% of the total variance. Fitter individuals (and/or those with less excess body fat), as well as younger individuals, are able to perform more curl‐ups than less fit, fatter or older individuals.

ISSN:1057-8315    

DOI:10.1080/15438629009511897

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

Exercise tolerance time and cardiac output (Q) measures during peak exercise were examined in 8 children with repaired congenital heart defects to determine the effects of physical training. Children ranged in age from 4.5 to 15 years (mean age 8.5). The children had undergone the following surgical repairs: Mustard operation for d‐trans‐position of the great arteries (n = 3); mitral valve replacement (n= 1); tetralogy of Fallot (n = 2); and Fontan operation (n= 2). Subjects participated in a 24‐session, 12‐week, one‐hour session hospital‐based aerobic exercise program of graduated intensity and duration. Work loads of 60, 70 and 80% of maximal heart rate were utilized. Graded exercise testing on a treadmill was performed prior to and following the training program. Pre and post values of Q were obtained via the acetylene rebreathing method. Exercise tolerance time increased significantly from 9.4 to 10.9 minutes (p<.01). Following training, peak exercise values of Q significantly increased from 4.91 to 6.05 L/min (p<.01). There were no complications. These data indicate that a monitored aerobic exercise program can increase exercise tolerance time and cardiac output values in children following corrective surgery for congenital cardiac defects.

ISSN:1057-8315    

DOI:10.1080/15438629009511898

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

ISSN:1057-8315    

DOI:10.1080/15438629009511899

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

ISSN:1057-8315    

DOI:10.1080/15438629009511891

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor