摘要:

The mean velocity of 9 out of 10 women's events during the U.S. Olympic Swimming Trials was greater in 1984 as compared to 1976. Three of the 10 men's events showed improvement. In 9 out of these 12 events, the increased velocity was accounted for by increased distance per stroke (range, 4 to 16%), and in 8 there was also a decrease in stroke rate (range, - 3 to -13%). In the women's 100-m butterfly and 100-m backstroke, increased velocity was due solely to faster stroke rates. The finalists in each event were compared to those whose velocities were 3-7% slower. In almost all events and stroke styles, the finalists achieved greater distances per stroke than did the slower group. In the men's events increased distance per stroke was associated with decreased stroke rate, except in the backstroke, in which both were increased for the finalists. Although the faster women swimmers generally had greater distances per stroke,they were more dependent than men on faster stroke rates to achieve superiority. The profile of velocity for races of 200 m and longer indicated that as fatigue developed the distance per stroke decreased. The faster swimmers compensated for this change by maintaining or increasing stroke rate more than did their slower competitors. This study indicates that improvements and superiority in stroke mechanics are reflected in the stroke rate and distance per stroke used to swim a race.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Ten well-trained male volleyball players performed one-legged and two-legged vertical countermovement jumps. Ground reaction forces, cinematographic data,and electromyographic data were recorded.Jumping height in one-legged jumps was 58.5% of that reached in two-legged jumps. Mean net torques in hip and ankle joints were higher in one-legged jumps. Net power output in the ankle joint was extremely high in one-legged jumps. This high power output was explained by a higher level of activation in both heads of m. gastrocnemius in the one-legged jump. A higher level of activation was also found in m. vastus medialis. These differences between unilateral and bilateral performance of the complex movement jumping were shown to be in agreement with differences reported in literature based on isometric and isokinetic experiments.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Oxygen uptake (VO2) was measured in males age 10-59 while they walked at 3 mph at various grades on a motor-driven treadmill. The number of subjects in each age group was as follows: age 10-11, N=24;age 12-13, N=46; age 14-15, N=55; age 16- 17, N=53; age 18-19, N=30; age 20-24, N=56; age 25-29, N=35; age 30-34, N=32; age 35-39, N=99; age 40-44, N=106; age 45-49, N=78; age 50-54, N=42; and age 55-59, N=11. Subjects walked at 3 mph at 0% grade for 3 min; thereafter, the treadmill was raised 3% every third minute with speed maintained. Oxygen uptake was measured continuously but only the values during the last minute at each grade were used in the present analysis. The subjects were in a “steady state,” insofar as VO2was concerned, by the second minute. These data were used to validate formulas for estimating VO2in horizontal and grade walking published inGuidelines for Graded Exercise Testing and ExercisePrescription (I). The formulas are accurate for estimating the mean oxygen requirement in grade walking from 6-18% in adult males. In horizontal walking and walking at 3% grade, the formulas underestimate VO2in all age groups. In boys under age 18, the formulas underestimate the energy requirement in walking at all grade levels. The error is about 0.5 ml·kgminus;1· minminus;1for each year under 18 years of age. It was concluded that when applied to adult populations, the formulas provide reasonable estimates of the actual oxygen requirement for treadmill walking provided the subjects are in a VO2steady-state.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The Daily Adjustable Progressive Resistive Exercise (DAPRE) technique was developed clinically in an effort to provide an objective means of increasing resistance concurrently with strength increases during knee rehabilitation subsequent to injury/surgery. The key to the DAPRE technique is that on the third and fourth sets of exercise the patient performs as many repetitions as possible. The number of repetitions performed during the third and fourth sets is used to determine the amount of weight that is added to (or sometimes removed from) the working weight for the next set and session, respectively. Consequently, patients exercise nearer their optimal capacity during each weight rehabilitation session, and their strength redevelopment occurs at a much faster rate. This report describes the quariceps muscle strength gains by 21 athletes who used the DAPRE technique following knee immobilization for a minimum of 3 wk. These patients averaged an increase of 4.3 ± 2.2 (SD) kg;d-1for a period of 6.4 ± 2.2 d, as measured by a six repetitions maximum test. It seems unlikely that morphological changes were responsible for these strength increases. It is postulated that strength redevelopment following immobilization involves changes in neural pathways and/or overcoming possible neural inhibitors

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The ability to index activity objectively in disabled or impaired activity populations is critical for our understanding of the long-term health consequences of reduced activity. The current research employed the large-scale integrated activity monitor as an objective measure of free living daily activity in 28 subjects with traumatic spinal cord injury. All the spinal cord-injured subjects wore the monitors for 2 d while in-patients at a rehabilitation center. The results indicated that the instruments can accurately index individual physical activity levels in this population, which has drastically reduced activity. Furthermore, group differences in activity were discriminated where paraplegic activity (mean, 32.0 counts-h-1) was significantly greater than quadriplegic activity (mean, 15.1 counts-h-1) (P<0.01) despite the markedly low activity levels. The results thus indicate that activity sensors can index individual activity levels at the very low end of the activity spectru.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The purpose of this investigation was to determine if a 9-wk youth soccer program had any effect on cardiorespiratory fitness (VO2maxand VO2submax), peak knee torque, and flexibility. Subjects were 20 sixth grade boys, 11 of whom were members pf a YMCA soccer team; 9 were normally active boys who were not participating in any organized sport during the study who served'as a control group. Mean ages (±SD) were 11.8 ± 0.34 and I; 1.5 ± 0.60 yr for the soccer and control group, respectively. Initial VO2maxvalues of 49.83 and 47.42 ml.kg-1-min-1for the soccer and the control group, respectively, are similar to those reported in the literature for untrained normal boys of this age. Results indicated that playing soccer three times weekly increased VEmaxand reduced VO2(ml.kg-1.min-1and|.min-1) at a submaximal running speed (all P's<0.O5), while no change in VO2maxwas noted. No significant training effect was observed in peak knee torque or flexibility subsequent to soccer training. It is concluded that the effects of playing soccer in these subjects resulted in no change in cardiprespiratory fitness, peak knee torque, or flexibility.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

To discriminate suitable fire fighters from recurring large groups of applicants, an objective test battery was developed which screened applicants on the basis of physical, psychomotor, and mental abilities. The physical and psychomotor selection procedures first involved fundamental tests of general aerobic endurance, upper body strength, and anaerobic endurance. Successful candidates progressed to more specific tests. Measurements were made of height, weight, hamstring flexibility, balance, strength, upper body flexibility, handeye coordination, and the ability to negotiate a fire fighting simulation course. Results of these tests were weighted, allocating 25% to physical tests, 20% to psychomotor tests, and 39% to the simulation course. These scores were then combined with scores of several knowledge tests weighted to be 16% of the whole. This provided a computergenerated ability profile of the top applicants which was considered at their interview before a final selection board of fire service officers. Selected candidates were then required to pass a medical examination. Pearson correlation coefficient analysis of 1984 test results demonstrated general independence of the tests (R=-0.34 to R=0.52), with the exception of bilateral grip strength (R=0.77). The first four trials of the selection procedure screened 3,172 applicants, 16.4% of whom were finally selected for interview. City officials estimated that based on a comparison of new and previously used selection procedures, cost savings of $92,500 were being achieved by 1984.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

As part of a prospective randomized trial of the effect of regular exercise in older men, factors determining the magnitude of V02maxincrease observed with endurance training were examined in 88 elderly [age 62.9 ± 3.0 (SD) yr] males. V02maxbefore and after training was recorded as the highest V02observed during two incremental treadmill tests. One year of thrice weekly training sessions increased V02max(12%, P<0.05) in the training group relative to baseline and to a control group (n=100). The association between the post-training V02max(V02max, T2) and the following explanatory variables was assessed using multiple regression analysis: the initial V02max(V02maxT1); the reason for stopping the initial treadmill test; leisure time activity during the year previous to the study; the training intensity (speed of walking or running, pulse rate during training, and percentage of heart rate reserve); pulmonary function (forced expiratory volume in 1 s); adiposity (skinfold thickness at 8 sites) and frequency of training. V02maxT1, speed of walking or running during training, reason for stopping the treadmill test, and skinfold thickness were significantly related to post-training V02max. The intensity and frequency of the training stimulus explained over 10% of the variance in the training effect. Subjects whose test was halted because of fatigue increased V02maxmore than those whose test was discontinued for medical or other reasons, even when speed of running was held constant. Previous activity had only a weak effect on training response. The total variance explained by these independent variables was 62%.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

To study substrate utilization during cold temperature exercise, seven men dressed in shorts, Tshirts, and light gloves performed 60 min of continuous cycle ergometer exercise at -10°C and 22°C. The workload at both temperatures represented 66% of the cycle-measured maximal heart rate. Oxygen consumption and respiratory exchange ratio (RER) were measured at rest and during 60 min of exercise. Rates of total and fat energy utilization (kJ.min-1)during exercise were calculated from VO2and RER. A two-factor repeated measures analysis of variance indicated that at rest oxygen consumption averaged 56% higher and RER 5% lower at — 10°C. During exercise, oxygen consumption averaged 10% higher (P<0.05), and RER averaged 2% lower (P<0.05) at - 10°C. The rates of total energy use (mean ± SD=39.3 ± 1.2 vs 35.7 ± 1.3 kJ min-1P<0.05) were significantly higher at -10°C than at 22°C. In addition, the rate of fat use increased significantly in both groups after 30 min of exercise. The cumulative total energy expenditure for 60 min of exercise was 13% higher (2379 ± 308 vs 2110 ± 415 kJ; P<0.O5 and the cumulative fat expenditure was 35% higher (979 ± 209 vs 724 ± 184 kJ; P<0.05) in the cold environment. These results indicate that a cold environment can significantly enhance fat utilization during endurance exercise.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Serum samples from 14 men and 8 women were obtained pre-marathon (48 h) and at 24, 48, 72, and 96 h post-race to quantitate total serum creatine kinase activity (TCK), percentage of creatine kinase MB (CK-MB), and clearance rates (half-lives) of TCK. and CK-MB. TCK was measured enzymatically, and the CK-MB isoenzyme was separated by agarose electrophoresis and quantitated by densitometry. The men's and women's post-race mean TCK levels were significantly elevated {P<0.05) above pre-race values at 24 h (3322 U.l-1, 946 U.lS-1) and 48 h (1787 U.l-1, 508 U.l-1). In addition, CK-MB was significantly elevated both 24 h (5.1 %, 3.3%) and 48 h (2.5%, 1.8%) post-race (P<0.05). The men's 24-h TCK was 22.3 times the prerace value, while the women had an 8.6-fold increase in TCK. The mean 24-h post-race CK-MB activities were 166 U.l-1for the men and 31 U.l-1for the women. The mean increase in CK-MB activity was 41.5-fold for the men and 7.8-fold for the women. Furthermore, the men had a mean half-life (t½) of 30.4 h for TCK and 12.0 h for CK-MB; the women's t½were 29.4 and 16.8 h, respectively. At all time points, the men evidenced significantly (P<0.05) higher TCK and CK-MB enzyme activities than did the women. The data indicate that men and women respond to the stress of marathon running with similar patterns of enzyme release, elevation, and clearance. The difference in absolute enzyme activities may be attributed to greater skeletal muscle damage of the larger muscle mass of men vs women.

ISSN:0195-9131    

出版商:OVID    

年代:1985

数据来源: OVID