ABSTRACT
Three middle-aged men (55-58 years) trained for 50 weeks. Exercise consisted of twelve minutes walking on the motor driven treadmill at the load of 70% of maximum oxygen intake, three times per week.<BR>Evaluations for maximal and submaximal work were made at 5-week intervals using treadmill walking method. Mean maximum oxygen intake improved 29.5% (26.1-39.7 %) over the 50-week period from 1.93 to 2.50 <I>l</I>/min, Mean maximum oxygen intake per body weight improved 24.5% from 34.9 to 43.5 ml/kg.min.<BR>But through the training session, the maximum values of maximum oxygen intake were obtained over the 25-week to 35-week period on each subject. After that period, maximum oxygen intake were unchanged or slightly dropped neverthless the training was continued.<BR>As the linear relationship was found between the oxygen intake and heart rates during exercise, the regression equations were calculated on each maximal test. The regression line might represent the oxygen pulse on each heart rates level during exercise. The oxygen pulse improved clealy also during submaximal work. The improve-ment of oxygen pulse were distinctive to 25-35 week period and after that no change were occured.<BR>In the submaximal test, there was seen clear improvement of efficiency during 20 minutes walking at the load of 70%, 50%, 30% of maximum oxygen intake respectively, even after the period that the increment of maximum oxygen intake could not be caused by training.