摘要:

Oxygen consumption, pulmonary ventilation and performance of 6 champion runners were observed over a 10-week period during which they trained alternately at sea level and 2300-meters altitude. Acute exposure to altitude resulted in a 14% drop in max VO2, 8% slower 1-mile and 10% slower 3-mile running times, and a 7% increase in max VEBTPS. By the 5th week at altitude max Vo2had risen to within 10% of sea-level control values (within 8% for subjects who had a 6th week at altitude), running times to within 3% and 8% of control, and max VEBTPS to 14% above control. Max VESTPD remained closely related to max Vo2and max VEBTPS to MVV during all altitude tests. In postaltitude tests max Vo2was 5% and max VE9% above prealtitude values. The subjects also ran 14 personal best times in post-altitude races. Vo2during sub-maximal running was higher following altitude training than before or during altitude tests; the subjects worked at 92–98% of max Vo2during their 3-mile race pace. It was concluded that intermittent sea-level stays of as long as 11 days did not interfere with altitude acclimatization and that both altitude and post-altitude performances benefited from the program.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

Body composition changes were evaluated in 55 men between the ages of 17 to 59 years following a 3-day/week, 10-week program of jogging. During this training period the subjects jogged a mean total of 51.75 miles in 413 minutes, at an average rate of 200 m/min. Small but significant reductions were found in body weight and percentage body fat (increased body density), although the total lean body mass remained essentially unchanged. Four of seven skinfold measurements of subcutaneous fat and one of two abdominal circumferences were significantly reduced. These changes in skinfold and circumference measurements were not highly correlated to the changes in body fat (kg) and body density, thus questioning the validity of using individual skinfolds solely to estimate alterations in body composition. Lastly, as expected, the relative amount of body fat was found to have a substantial negative influence on the performance of speed or endurance-related activities requiring the movement of the body mass.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

The metabolic, heart rate and ventilatory patterns and physical work capacity in bicycle and treadmill exercise were compared in 23 male college students. The average reduction in max Vo2of .324 l/min (9.9%) observed during bicycle work was highly significant (P < 0.01). The standard error of the prediction for max Vo2on the treadmill from observed values on the bicycle ergometer was ± .291 l/min (r=0.82). Minute ventilatory volume was similar at all measured work levels in both forms of exercise with the respiratory exchange ratio being significantly higher on the bicycle at submaximal heart rates and at max Vo2A significantly larger percentage of the max Vo2was elicited at submaximal heart rates on the bicycle when compared to similar heart rates on the treadmill. At max Vo2the heart rate was significantly lower in the bicycle test. PWC150and PWC170on the bicycle ergometer correlated fairly well with similar measures on the treadmill. However, when PWCmaxwas compared in both tests the relationship was significantly reduced (r=0.34). PWC on the bicycle was favored more by a high absolute max Vo2(l/min), whereas the relative max Vo2(ml/kg/min) was highly related to treadmill exercise. This was particularly demonstrated at PWCmaxon the treadmill with work capacity correlating r=0.92 and r=0.37 with relative and absolute max Vo2, respectively. However, when the effect of body weight was held statistically constant the partial correlation between max Vo2(l/min) and PWCmaxon the treadmill increased to r12.3=0.91. Expressing the oxygen uptake in terms of lean body weight did not improve its relationship to PWC on the bicycle or treadmill.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

The estimation of maximal oxygen consumption (max Vo2) from a simple submaximal test has been of interest for many years, especially for middle-aged men. The object of the present study was to compare the prediction of max Vo2obtained by simple regression with that obtained by stepwise multiple regression. The subjects, 13 middle-aged men, were exercised on a bicycle ergometer to max Vo2(P < 0.10) as determined by the Haldane-Douglas bag method. Heart rate, systolic and diastolic blood pressure, expired volume, expired CO2and O2were determined. The multiple regression equation predicted max Vo2better than the simple regression equation because several of the cardiovascular and respiratory variables are significant predictors and do not contain identical information. For middle-aged men, the multiple regression equation provided a correlation with max Vo2that was significantly superior to that obtained by simple regression. This suggests that fallibility may be reduced in the prediction of max Vo2by relying on more than a single cardiovascular or respiratory variable in the prediction equation.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

Female college students between the ages of 18 and 37 exercised using a bicycle ergometer. Exercise was performed to maximal to maximal lavels by increasing the work load 150 kpm/min each minute and at a later time exercising until exhaustion at a constant work level equal to the maximal work level attained with the step increment exercise. The maximal steady work load was maintained for between 2.5 to 4 minute and was accompanied by higher ventilations and oxygen uptakes than were observed during the incremental test. The inability of the subjects to elevate their ventilation with the step increment work test appeared to to be related to the time for adjustments to occur with exercise and to motivational factors.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

The purpose of the study was to investigate the effects of body position (supine and sitting) and a submaximal exercise task on a bicycle ergometer on left ventricular intervals. The intervals were determined from simultaneous records of the carotid pulse wave, phonocardiogram, and EKG. The subjects were 64 male volunteers, 22 to 62 years of age. It was found that changing body position from supine to sitting caused significant reductions in cardiac cycle time, diastole, and ejection period and lengthening in isovolumetric contraction period. Submaximal exercise caused significant reductions in diastole, electromechanical lag, isovolumetric contraction period, and ejection period. The time components of the left ventricle (eight intervals recorded under five conditions) can be described by 11 orthogonal factors. Isovolumetric contraction period was found to be specific for each test condition. Age, height, and weight were relatively independent of the elft ventricular intervals.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

The purpose of this study was to examine the relationship between resting platelet count and levels of physical fitness as determined by the Harvard step test. It was hypothesized that the two variables are inversely related. Platelet counts and Harvard step test scores were obtained from 102 male subjects. Blood samples were obtained via fingertip puncture and the platelet count assessed by means of the Brecher-Cronkite method. The step test was performed in a controlled environment room. A Pearson product-moment correlation coefficient was calculated for resting platelet counts and fitness scores and found to be significant (P < .05). It was shown, however, to lack predictive power. A subsequent test for linearity, i.e., eta, failed to achieve significance. The subjects were sorted into high, moderate, and low fitness groups on the basis of their step test scores. A one-way analysis of variance revealed no difference between these groups. Finally, attest was performed between the platelet counts of the extremes of the fitness distribution. No difference was revealed. It was concluded within the limits of this study that there is no relationship between resting platelet count and physical fitness level, as determined by the Harvard step test.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

Proteinuria and the appearance of formed elements in urine have been demonstrated with regularity in well trained runners following a 20 km crosscountry race. The rate of protein excretion increased above the pre-exercise value in 41 of 51 men. Correspondingly, the rates of urine and creatinine excretion decreased. Glucose was found in the exercise urine of two subjects who had the greatest rates of protein excretion. Epithelial cells, white cells, red cells, hyaline casts, and granular casts in urine were associated with exercise in 52 men from the same population. It appears that proteinuria is involved in cast formation as a result of exercise. We conclude that the syndrome “athletic pseudonephritis” is a regular phenomenon after heavy exercise.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

The horizontal and vertical force-time relationships that occur at the take-off board for the Running Long Jump are presented. These relationships are manipulated using the impulse-momentum equations of physics to yield the take-off velocities in the horizontal and vertical directions. It is shown that the maximum vertical force exerted at take-off is not the sole parameter, but the combination of the force, impulse, and mass of the athlete is the primary factor. It is also shown that the horizontal forces that exist at take-off act to decrease the horizontal take-off velocity.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

A theory concerning relative running performance measurement is proposed and a model for this theory is derived which generates a reference time for any given distance. Construction of scoring tables from the reference time is presented. These “mathematically based” tables provide a rating system for all performances at a given distance. The algorithm which constructs the scoring tables was programmed for a computer, and sample output is given. Comparisons are made between many of the current world records. These comparisons indicate that these tables are more consistent than other previously existing tables, although a thorough validation still needs to be performed. Finally, a modification is developed which generates tables of sub-maximum running speeds that may be utilized in interval training.

ISSN:0025-7990    

出版商:OVID    

年代:1970

数据来源: OVID