摘要:

Twenty‐three female members of the United States Speed Skating Team were evaluated and followed during four years of preparation for the 1988 Olympic Winter Games. Those skaters who reported having prolonged inter‐menstrual intervals had the highest average menarcheal age of 14.2 years. This was significantly older than the average menarcheal age of 13 years among skaters who did not report menstrual disruption. Skaters who began intense training in late childhood tended to later menarche and prolonged intermenstrual intervals when compared with skaters who initiated their training earlier, but these differences did not reach statistical significance. Menstrual disruption in subjects during the course of these observations was unusual; although many skaters reached very high levels of training and those who were involved in pre‐Olympic competitions achieved extremely low proportions of body fat content.

ISSN:1057-8315    

DOI:10.1080/15438629109511901

出版商:Taylor&Francis Group    

年代:1991

数据来源: Taylor

摘要:

The investigation of the influence of short‐term exhaustive exercise on platelet function (aggregation andin vivoactivation) in young athletes competing in different sports was the purpose of the study. In 15 athletes aged 15 to 22 years plasma beta‐thromboglobulin and platelet aggregation were estimated before, 3 minutes, and 30 minutes after short‐term exhaustive exercise. The exercise led to an increase ofin vivoplatelet activation that was manifested in an increase of plasma beta‐thromboglobulin level 3 minutes after exercise. Platelet aggregation—the initial as well as adrenaline‐and adenosine diphosphate (ADP)‐induced—was not significantly different from the resting value at this time, but 30 minutes after exercise the total adrenaline‐and ADP‐induced platelet aggregation was decreased. The findings indicate the complex influence of exercise on hemostasis that is of importance not only for patients with atherosclerotic complications, but also for active athletes.

ISSN:1057-8315    

DOI:10.1080/15438629109511902

出版商:Taylor&Francis Group    

年代:1991

数据来源: Taylor

摘要:

Twenty college‐age males participated in a weight‐training experiment, three sets of 10 repetitions at 70% one repetition maximum (1 RM) for the squat, to examine the time course relationship between prostaglandin (PG) formation, creatine kinase (CK) activity, and ratings of perceived soreness (RPS). Two groups of 10 each received aspirin (3 g/day) or placebo for 4 consecutive days, starting 1 day prior to workout. There was no significant difference between the groups for CK and RPS during the course of the experiment, but the PG values were significantly different (p<0.05) between groups at all time points measured. Changes observed in biochemical parameters followed an exponential growth and decay during the period following exercise for all variables. The 24 hour PG level was significantly higher(p<0.05) than the pre‐and postexercise and 72 hour levels, but not significantly different from the 48 hour level. Ratings of soreness were not significantly different at the 24 and 48 hour intervals, but both were significantly higher at all other time intervals. The mean CK activity at the 24 and 48 hour intervals was not significantly different, but the 24 hour serum CK activity was significantly higher (p<0.05) than the other time intervals. In conclusion, PGs do not seem to have any significant effect on the CK activity nor on the delayed onset of muscle soreness. However, given the small sample and interindividual variations, further investigation concerning the role of PGs on delayed onset of muscle soreness should be conducted.

ISSN:1057-8315    

DOI:10.1080/15438629109511903

出版商:Taylor&Francis Group    

年代:1991

数据来源: Taylor

摘要:

Fifty‐four moderately trained men were evaluated following resistance training to determine the contribution of structural dimensions to maximal bench press lifting capacity. Muscle circumferences were taken around the flexed upper arm and the relaxed chest. Skeletal dimensions included the length of the upper and lower arm, the drop distance of the bar during the bench press lift, and the width between the hands on the lifting bar. Skinfolds were used to estimate body composition. Multiple regression analysis selected upper arm muscle plus bone cross‐sectional area, age, upper arm length, and lean body mass as the best predictors of bench press performance (r= 0.79, standard error of estimate = 13.8 kg). Prediction of Schwartz rating bench press (r = 0.59) and bench press/ kg (r= 0.56) from anthropometric dimensions were less successful but used similar variables. Body mass, either in the form of total body mass or lean body mass, appeared to be the major factor influencing bench press performance. In addition, individuals with shorter, more muscular arms at a given body mass performed better in the bench press lift.

ISSN:1057-8315    

DOI:10.1080/15438629109511904

出版商:Taylor&Francis Group    

年代:1991

数据来源: Taylor

摘要:

The relationship between exercise and knee ligament laxity has been explored to some degree in recent research. However, previous studies have focused on athletes participating in a variety of sporting activities with great variance in exercise bouts. This study evaluated anterior cruciate ligament laxity, using the KT‐1000 knee ligament arthrometer, in 50 male and female basketball players before and immediately after a controlled muscular fatiguing isokinetic exercise protocol. Significant pre‐and postexercise differences (p<0.05) in ligament laxity were seen in the combined group of males and females only at 25°±5°of knee flexion with 15 to 20 pounds of anterior displacement (left leg) and 20 pounds of posterior displacement (right leg). In the male athletes, significant pre‐and postdifferences were found at 25°±5°of knee flexion with 15 and 20 pounds of anterior displacement (left leg). No significant before to after differences were observed among female athletes.

ISSN:1057-8315    

DOI:10.1080/15438629109511905

出版商:Taylor&Francis Group    

年代:1991

数据来源: Taylor

摘要:

Forty‐five female handball players were trained during 8 weeks with a frequency of two sessions per week. They were divided at random into three groups of 15 subjects each: (1) a control group with normal training, using normal handballs (approximately 400 g); (2) the heavy training group (HT) exercised with a heavy ball (approximately 500 g); and (3) the light training group (LT) exercised with a light ball (approximately 300 g). In the two experimental groups the players completed a specific throwing session of 30 maximal overarm throws in addition to the normal training. After 8 weeks of practice in this maximal overarm throw, there was a significant (p≤0.01) increase in ball velocity of 0.4 m/sec in the LT group and no increase in the HT group. Maximal isokinetic and isometric torque measurements of medial shoulder rotation and elbow extension showed no significant changes in any of the groups following training. The LT group, however, showed a significant(p≤0.01) increase in both movements of the torque at 160, 240, and 320 msec of a maximal contraction during 3 seconds. These results indicate that a training with overload of velocity increases ball velocity from the standing overarm throw.

ISSN:1057-8315    

DOI:10.1080/15438629109511906

出版商:Taylor&Francis Group    

年代:1991

数据来源: Taylor

摘要:

The purpose of this study was to examine exercise intensity while perceptually pacing at 12 to 14 (somewhat hard) on the Borg scale during outdoor running. Maximal oxygen uptake (VO2max), ventilatory threshold, and related variables were measured during treadmill running. Submax VO2was collected during a 1.6 km run while pacing between 12 and 14 on the Borg scale. In order to collect expired gases during this run, a Douglas bag was fitted to a backpack frame and data were collected during the last 0.4 km of the 1.6 km run. To minimize pacing errors, three 2.4 km runs while perceptually pacing were completed. VO2maxaveraged 41.3 ml‐min‐1.kg‐1and ventilatory threshold was 64.4% of VO2max. The submax VO2while perceptually pacing was 71.2%of VO2max. This value was slightly, although nonsignificantly(p>0.05), higher than the percentage of VO2maxat ventilatory threshold. The results indicate that distance run pacing at 12 to 14 on the Borg scale is near ventilatory threshold and within the acceptable exercise intensity range indicated by the American College of Sports Medicine to produce cardiorespira‐tory training adaptations.

ISSN:1057-8315    

DOI:10.1080/15438629109511907

出版商:Taylor&Francis Group    

年代:1991

数据来源: Taylor

摘要:

This research project was designed to assess the causal influence of wearing an“air belt”; (pneumatic lumbar support) on the development of muscular strength, hip and back flexibility, and a functional impairment (pain) index. Thirty subjects were randomly selected from a pool of individuals who were diagnosed as having muscular strain/sprain of the lower back by an orthopedic‐neurologic examination. They were graded as mild, moderate, or severe. Subjects in the treatment and control groups were matched according to gender and grade of strain/sprain. Each subject was tested initially, again after I hour, 3 weeks into the program, and finally post‐tested after 6 weeks of therapy or control. Subjects in the treatment group were required to wear the air belt for 1 hour after a pretest, then for 6 hours a day, 5 days a week for the 6 weeks of rehabilitation. Gain scores were analyzed using an analysis of covariance (ANCOVA) with age and pain as the covariates, p≤s 0.05. Muscular strength improved 4.9% after wearing the air belt for 1 hour, 11.5% after 3 weeks, and 16.1% after 6 weeks of use. Since these individuals were functionally impaired as a result of lower back sprain/strain, the air belt does appear to improve substantially the strength otherwise lost due to a lower back injury. The ANCOVA tests for flexibility and pain index gain scores at acute, midchronic, and chronic stages of testing and therapy were all found to be significant. Therefore, it may be concluded that use of the air belt aids in flexibility and lessens the pain perceived in functionally impaired individuals. Subjective assessment of pain decreased by 18% after 1 hour of air belt use, 46% after 3 weeks of use, and 73% after 6 weeks of use. Flexibility improved 35%, 70%, and 93% during the same period. These results indicate how use of the air belt may lessen the pain associated with low‐back injury and may help increase strength and flexibility, thus facilitating a return to normal daily activity.

ISSN:1057-8315    

DOI:10.1080/15438629109511908

出版商:Taylor&Francis Group    

年代:1991

数据来源: Taylor

摘要:

Attention is drawn to the possible distortion of results in randomized trials of exercise‐centered rehabilitation following myocardial infarction, due to a poor compliance of patients with the assigned form of treatment. The possibility of a post‐hoc classification of exercise behavior is explored, with particular reference to data obtained in the Ontario Exercise‐Heart Collaborative Study, which compared the therapeutic efficacy of high‐intensity exercise (HIE) and light‐intensity exercise (LIE) programs. On the basis of the heart rate observed during cycle ergometer exercise at an oxygen consumption of 1.25 l‐min‐1, subjects were assigned to a HIE‐trained subgroup (92 of the patients originally assigned to HIE, with a decrease in exercise heart rate>5 beats‐min‐1during the first year of observation), and a LIE‐control subgroup (102 of the patients originally assigned to LIE, with a decrease in exercise heart rate<5 beats‐min‐1over the first year). After this reclassification, the odds ratio relating the risk of reinfarction for HIE‐trained to LIE‐control was decreased, but still did not differ significantly from 1.00 (mean, 0.74; confidence interval, 0.20 to 2.65). Moreover, reasons are advanced to suggest that because of a selection of subjects, reclassification may have reduced the risk of recurrence for the HIE group, while increasing the risk for the LIE group. It is concluded that practical obstacles will preclude formal statistical proof of the exercise hypothesis for the postcoronary patient for the forseeable future.

ISSN:1057-8315    

DOI:10.1080/15438629109511909

出版商:Taylor&Francis Group    

年代:1991

数据来源: Taylor

摘要:

This study monitored the physical fitness of nine divisional Alpine skiers at three points in the annual training season. The first assessment (September) followed a summer training program, with the second and third assessments at the start (December) and end (April) of the Alpine ski season. The test battery included: (1) an anaerobic cycling test, (2) an aerobic cycling test, (3) two sport‐specific jumping tests, and (4) two tests of muscular endurance. Results showed minimal change in the physical fitness of the skiers from the start to the end of the skiing season in spite of daily on‐snow practices, weekly races, and supplementary dry‐land training, all aimed at promoting development of the divisional skiers to national caliber.

ISSN:1057-8315    

DOI:10.1080/15438629109511910

出版商:Taylor&Francis Group    

年代:1991

数据来源: Taylor