Nineteen volunteer men, between 28–39 years of age (mean 32.5) were randomly assigned to one of the two experimental groups. Group I exercised two days a week, and Group II four clays a week for twenty weeks. Exercise sessions were 30 minutes in duration and consisted of continuous walking, jogging, or running. A control group of 8 sedentary men did not differ significantly in working capacity and cardiovascular function, but body composition tended to deteriorate. During this same time span, both experimental groups improved significantly in all working capacity and cardiovascular variables. This was shown by increased maximal VO2 from 3.030 to 3.531 l/min (17%), and 2.903 to 3.752 l/min and 36.6 to 49.3 ml/kg/min (35%), maximal pulmonary ventilation from 127.2 to 140.8 1/min and 128.9 to 142.6 l/min, maximal oxygen pulse from 16.6 to 19.8 ml/b and 16.4 to 21.6 ml/b for Groups I and II respectively. A heart rate response to a standard treadmill (5 min, 6 mph, 5.0% grade) test was administered to evaluate changes in cardiovascular efficiency with training. Both experimental groups improved significantly in all rest, exercise, and recovery heart rate measures. Body composition values remained relatively constant for Group I, but improved significantly for Group II. Group II decreased significantly in total body weight (-2.9 kg), per cent body fat (-1.0%), and the sum of 6 skinfold fat measures (-23.6 mm.) The between group analysis showed that improvements were manifested in accordance with frequency of participation.
©1969The American College of Sports Medicine