摘要:

Oxygen uptake during and after exercise has been discussed in reference to the concept of oxygen debt. An attempt has been made to identify the factors which contribute to O2deficit, steady level of oxygen uptake and recovery oxygen. These factors may be grouped into three general categories: (1) use and replacement of energy stores (2) energy for contractile activity and (3) energy for metabolite turnover.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

Four running tests were performed by five, normal, male adults on a motor driven treadmill. After determination of the max &OV0312;o2they ran on different days for 30 minutes at 82–89% max&OV0312;o2, 40 minutes at 74–79% max&OV0312;o2and 60 minutes at 67–74% max&OV0312;o2. Gas exchange determinations and basilic vein lactate measurements were made for selected one-minute intervals over the duration of the runs. Periodic pH determinations, heart rates and rectal temperatures were monitored.In running at 82–89% max&OV0312;o2the venous lactate levels were observed to continuously increase over the duration of the 30 minute performances for all subjects (peak mean 82.5mg%). Running at 74–79% max&OV0312;o2resulted in an elevation. of lactate that generally plateaued around 45mg% by the 20th minute of the 40 minute performances. At 67–74% max&OV0312;o2a small increase in lactate occured (means ranged from 18 to 29mg%) which was sustained over the 60 minute performances.The results indicate that blood LA is elevated over the duration of 30 to 60 minute runs in proportion to the aerobic demands in excess of 65 to 70% of maximum. This suggests that LA is continuously produced in work requiring 65 to 90% max&OV0312;o2even when a reasonably steady state of O2consumption is attained.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

Twelve male subjects were submitted to an intense arm exercise exhaustion. Analysis of venous blood, taken at the elbow, revealed that:—during the exercise, there was a higher increase in the hematocrit than in serum protein concetration,—at the end of the exercise, the correlation between the increase of the hematocrit and of serum proteins was not significant, but became significant after 3 min. of recovery.The increase of both the hematocrit and the serum proteins is not due exclusively to plasma concentration. The hypothesis is advanced for protein transfer to the circulation.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

The purpose of this study was to determine if catecholamine (CA) excretion could provide an “index” of work strain to facilitate comparisons between subjects differing in work capacity. CA excretion was measured in four subjects at different intensities of treadmill running exercise. CA excretion showed the highest correlation (r = 0.81) to work intensity when expressed as a percent of max&OV0312;o2, rather than to &OV0312;o2in absolute terms (liters/min) or per kilogram of body weight (ml/kg·min). CA excretion might be useful as an index of work strain for group comparisons, but does not precisely express the strain experienced by any one subject.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

Thirty-six young male college students were randomly assigned to the cells of a 3 x 2 factorial design which included three levels of training intensity (training heart rates of 130, 150 and 170 beats per minute) and two levels of duration (7500 or 15,000 kpm total work). The six week training program was conducted on bicycle ergometers, three days per week. Prepost training differences on three cardiorespiratory tests (step test prediction of aerobic capacity, progressive treadmill test, bicycle test) did not reveal significant intensity, duration or interaction effects. Fitness changes yielded a highly significant negative correlation when related to the previous level of fitness, as tested on the training device. A comparison group of eighteen adult men were trained in a slightly modified design. Highly significant interaction effects were noted in one test condition. The cardiorespiratory endurance tests used were related, but they seemed to measure different aspects of the changes due to training.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

Middle-aged men who volitionally participate in physical activities differ from their sedentary peers in several ways. Data from a Physical Activity History questionnaire suggested the following profile of a volitionally active man: he grew up in an urban area; had parents who encouraged his participation in sports; was a member of high school and college athletic teams; had more years of formal education; had always participated in vigorous activity; and, enjoyed competition and the feeling of fatigue that followed strenuous exercise. A positive attitude toward physical activity was formed early in life and became a meaningful part of his life style. In a sedentary group of middle-aged men who were assigned to exercise or nonexercise groups, the exercise group was scheduled to participate in a supervised program of regular physical activity. After one year the exercise, nonexercise, and volitionally active groups completed a Physical Activity Attitude Inventory. In general attitudes of formerly sedentary men who were made active approached those held by volitionally active men. It was concluded that a program of regular exercise may intervene in the lives of middle-aged men and produce measurable changes in attitude toward exercise.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

A comparative study was made between levels of activity and morphological variables in a sample of 186 adult males, aged 45 to 64 years, from Tecumseh, Michigan. Among the morphological variables studied, only arm muscle size was consistently greater in habitually active males. The rate of decrease of cortical bone and muscle size with age does not appear to be related to levels of physical activity.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

The interrelationships of depression, age, height, weight, percent body fat, strength of grip, and physical working capacity were evaluated in 67 normal adult males. None of the correlations were statistically significant (P > .05). Also, the multiple correlation between depression and the physical variables was low (R = .28). In addition, 101 adult males participated in an exercise program which consisted of circult training (N = 18), jogging (N = 23), swimming (N = 27), treadmill running and bicycle ergometry (N = 17), and 16 subjects served as controls. It was found that six weeks of exercise did not produce a significant reduction in depression for any of the groups. However, a significant (P < .01) reduction in depression was observed in those subjects (N = 11) who were depressed initially. It was concluded that depression was not signifcantly correlated with variables such as age, height, weight, percent fat, strength of grip, and physical work capacity in normal adult males. Also, depressed adult males can experience a significant reduction in depression following six weeks of chronic exercise somatotherapy.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

An electromyographic study was conducted using the vastus medialis and the vastus lateralis muscles in three isometric exercises and in cable-tension tests for knee extension with the leg-thigh angle at 110 degrees and 170 degrees during maximal, 60 percent of maximal and 20 percent of maximal contractions. The results indicated that: (1) the isometric exercises evoke action potentials in the vastus medialis and the vastus lateralis generally equivalent to or somewhat greater than the action potentials recorded during the cable-tension tests requiring 60 percent of maximal contraction, (2) the action potentials recorded during the isometric exercises were not altogether similar from exercise to exercise and (3) the action potentials recorded from the vastus medialis and the vastus lateralis during maximal contraction at 170 degrees were not significantly different from those recorded at 110 degrees.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID