摘要:

Progressive work capacity tests were designed attempting to provide comparable energy demands on the treadmill, bicycle and adjustable stepping device. The respective initial work stresses 3.0 mph — 2.5% grade, 60 Watts — 50 revs/minute and 30 steps/min — 4.5 cm step height, were estimated to demand &OV0312;o2responses 4 x rest (4 Mets). Each work increment, applied every 2 minutes, was 2.5% for treadmill, 25 Watts for bicycle and 4.5 cm for the step device and was estimated to increase &OV0312;o2by 1 Met. To test the accuracy of the &OV0312;o2estimates and possible interchangeability of tests, 10 healthy male adults performed the three tests randomly and &OV0312;o2was measured during the 2nd and final minute at each load. In addition, all subjects performed a series of 5-minute tests for comparison of each of the 5 minute &OV0312;o2values (the fifth minute value being the criterion for “steady state”) with those measured at identical loads in the progressive test.There were no differences (P > .05) between &OV0312;o2values measured in the 5th minute of the 5-minute tests and those at identical loads in the progressive tests. In most instances &OV0312;o2demands were met by the 2nd minute in the 5-minute tests.The progressive test &OV0312;o2measured responses for the treadmill, bicycle and step device were found to be unique to the instrument loads used. However, load corrections were calculated that would elicit a single-line metabolic response for the loadings on the three tests. The heart rate responses were found to be similar for the three tests while the ventilation responses appeared unique to the test instrument used.

ISSN:0025-7990    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

Exercise metabolism, heart rate, and work output were measured for seven competitive oarsmen. Oxygen consumption was assessed by open-circuit method and heart rate telemetered during progressive strenuous exertion in a rowing training tank. Work output was determined by a strain gauge-recorder arrangement. Heart rate was also telemetered periodically during a strenuous training session of 2000 m on the river so that a comparison of the relative contribution of aerobic work could be made between tank and river work. Oxygen consumptions for the tank test ranged from 4100–5344 ml/min and heart rates from 176–192 beats/min. Work output, which was supposed to be standard, ranged from .530–.715 · h.p. Heart rates for river work ranged from 164–178 beats/min. Work output in the tank was successfully measured by the strain gaugerecorder instrumentation and for most subjects standardization was attained. Tank oxygen consumptions and heart rates for most oarsmen approached maximal levels. Comparative heart rates showed that the river work, on the average, required less energy expenditure.

ISSN:0025-7990    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

Fourteen boys, aged 10–15, were tested on five occasions during 22 months of distance-running training. Semi-annually, height and weight were recorded as were performances for 1− and 2-mile races. Sub-maximal and max&OV0312;o2were also determined from expired gas samples which were collected during treadmill running. After 22 months, average growth was 11.2 cm and 9.2 kg. Max&OV0312;o3increased from 2331 ml to 2839 ml; max&OV0312;o2/kg did not change significantly from a mean of 59.5 ml/kg per minute. During the 12-month period of greatest growth (6.4 cm and 5.9 kg), max&OV0312;o2increased 295 ml, a. 50 ml increase per kg increase in weight. Again no change was measured in max&OV0312;o2/kg. Average improvement in running performance was 32 seconds in the mile and 63 seconds in 2 miles. Steady-state Vo2(ml/kg per min) during running at 202 m/min gradually diminished from 52.0 in the initial test series to 45.5 22 months later. This apparent improvement in running efficiency, which was to a great degree a function of growth, was believed to be (along with possible increased anaerobic activity) mainly responsible for better running performance.

ISSN:0025-7990    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

There was no significant correlation between directly measured maxVo2and indices derived from Cameron Heartometer brachial pulse wave recordings in sixty-five men, forty to sixty-five years of age. These indices are of no value in assessing the cardiovascular fitness of middle-aged men.

ISSN:0025-7990    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

The phases of systole, i.e., total electromechanical systole (QS2), pre-ejection period (PEP), and left ventricular ejection time (LVET) were recorded on seven recumbent cross-country runners; measurements were made at rest, and immediately after completing a multistage treadmill walk (peak O2requirement 51.3 ml/kg per min), a three-mile run in twenty minutes and a second graded walk to a similar level of O2consumption. The LVET was corrected for heart rate, using a regression formula to compute the left ventricular ejection time index (LVETI). Physical exercise produced significant shortening of PEP and LVETI. Both PEP and LVETI returned to near control values five minutes following the three-mile run. These findings suggest that the rate of myocardial fiber shortening is accelerated during physical exercise in crosscountry runners, and that a prolonged aerobic run does not exert deleterious effects upon cardiac performance.

ISSN:0025-7990    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

The T wave amplitude changes were evaluated on 19 men between the ages of 24 and 62 years following a 3-day/week, 10-week progressive jogging and rhythmic exercise program. Significant increases in the amplitude of the T wave were found sitting at rest, during the last 10 secs of the second min of a bicycle ergometer ride (25 kg-m/sec at 60 rpm), and during the last 10 secs of the first and third mins of recovery. Insignificant increases in favor of the training group were present in the second, fourth, eighth, and tenth mins of recovery.

ISSN:0025-7990    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

Rectal (Tre), auditory canal (Tac) and mean skin (&OV0374;sk) temperatures and various metabolic measurements were taken on five men during 70-min exercise periods, in the upright and supine positions, on a bicycle ergometer at an average relative Vo2of 43%. The men were tested under the four combinations of continuous and intermittent (30 sec work-rest cycles) exercise in the upright and supine positions. The purpose was (a) to confirm the elevated Trewith intermittent work; (b) to determine if these higher core temperatures were due to orthostatic reactions; and (c) to determine if the intermittent mode and/or the supine position would modify exercise temperature regulation. In all four experiments sweat rate and energy production were the same. In the upright position equilibrium Treduring intermittent work was 0.13°C higher than in continuous work; in the supine position the comparable intermittent Trewas elevated 0.28°C. The greatest increase in Tre(+ 1.56°C) occurred during the intermittent-supine experiment where the decrease in Tsk(— 0.67°C) was least. Equilibrium Tskwas elevated 0.75°C in the supine position. With similar sweat rates, intermittent exercise results in increased Trewhile the supine position includes higher Tsk. The elimination of orthostatic reactions with supine exercise does not attenuate the higher intermittent work Tre. The results indicate nonlinear relationships between sweating and core and skin temperatures and suggest the action of undefined thermal and/or nonthermal inputs in the control of exercise temperature regulation.

ISSN:0025-7990    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

Twenty-three college men participated in a running and walking conditioning program five days per week for nine weeks. Subjects were categorized into the following groups based on their relative fatness; an obese group ranging in fatness from 25%–46% (N=8), and a lean group ranging in fatness from 10%–21% (N=15). The approximated energy expenditure prescribed for each subject was estimated to be 600 keal per day of physical conditioning. No attempt was made to control the diet. During the physical conditioning interval significant decrements in body fat and increments in fat-free body weight were observed for both groups in anthropometric, densitometric and hydrometric analyses of body composition. The sum of ten subcutaneous fat measures decreased. Body density increased. Relative total body water increased while extracellular water remained relatively constant suggesting an increase in the intracellular water compartment. Total blood volume and plasma volume did not significantly change. Although the average body composition changes in the obese group were larger, the differences in the mean changes between the groups were relatively similar. A discrepancy was found between the estimated energy expended during exercise and the energy lost due to changes in body composition.

ISSN:0025-7990    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

The body composition of 94 high school wrestlers, 15 to 18 years of age and 98 to 233 lbs., was measured using skinfold and girth measurements. Three regression formulae were used to predict body density and percent body fat, and comparisons were made by age and wrestling weight category. There was a 25% increase in total body fat from age 15 to 18, while individual skinfolds increased 37% for the scapula, 28% for the iliac and 19% for the abdomen. The bicep showed a small increase of 2%, while triceps fat decreased 5%. When the wrestlers were grouped into one of 13 wrestling weight groups, the absolute skin-fold values increased with weight increases. Comparing the two most extreme groups, the heaviest individuals (208 pounds) had 208% more total skinfold fat and possessed almost four times as much body fat as the 98 pound individuals (15.5% compared with 4.2%). The predicted values of density and fat were lower than previously reported for age and weight matched groups of young athletes except for the heavier weight groups. The increase in percent fat with wrestling weight category suggests that either heavier high school wrestlers should be expected to have greater fat because of an age effect, or that at the heavier weight levels the concern for weight control is not as important with the athlete who may feel it is advantageous to gain weight.

ISSN:0025-7990    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

Of 10,216 male athletic injuries treated at the University of Toronto between September 1951 and June 1969, 23.2% were incurred in the intercollegiate (IC) and 41.9% in the intramural (IM) programs. Accident rates averaged 509 injuries per 1000 participant years for IC athletes, and 57 injuries per 1000 participant years for IM athletes; accidents were particularly frequent in IC football, wrestling, rugby, basketball, and soccer, and in IM football.Statistics for all IC athletics except boxing showed little improvement between 1951 and 1969; however, IM injuries for rugby, lacrosse, hockey and soccer all decreased over the period of analysis. Possible reasons for these trends are discussed.Injury rates reached a peak near the middle of the season, when IM competition was most intense. Rates were highest in physical and health education and graduate students; intense competition may have been a factor in the physical education athletes, but poor preparation and aging seemed more likely reasons for accidents among the graduates.The type and bodily distribution of injuries conformed generally with expected patterns. Certain sports (squash, skiing, gymnasties, basketball, and judo) carried a particular risk of recurrent sprains and dislocations; the shoulder, knee and ankle joints were most commonly affected.The current frequency of injury is unsatisfactory for many types of sport. As a first step towards the development of effective preventive measures, specific suggestions are made for the uniform reporting of injury data.

ISSN:0025-7990    

出版商:OVID    

年代:1971

数据来源: OVID