|
In order to investigate the changes in oxygen uptake during treadmill walking according to speed and grade of inclination, 74male and 33 female college students who volunteered were subjected to this study. Speed of treadmill was set to 2,4,6 and 8㎞/hr, and grade of inclination ranged from 0(level) to 25% for the male and from 0 to 12.5% for the female subjects. Oxygen uptake during treadmill walking was measured by Douglas bag method using Orzat gas analyzer. Oxygen uptake during treadmill walking increased rectilinearly with increment of speed or grade of inclination, and could be expressed as simple linear regressions of VO_2 on speed for each grade, or on grade for each speed. Average VO_2 predicted by these regression equations was proved to be valid showing the regression of the predicted on the actual value was VO_2 pred.=1.00VO_2actual-0.31(r=1.0000, S.E.E.=0.51) for the male, and VO_2pred.=1.00 VO_2actual+0.15(r=1,0000, S.E.E.=5.0) for the female. Meanwhile, although VO_2 predicted by multiple linear regression on both speed and grade of inclination(table 4) was also well correlated with the actual values VO_2pred.=0.43 VO_2actual+704.4(r=0.9860, S.E.E.=4.0) for males; VO_2pred.= 0.98 VO_2actual+32.1 (r=0.9879, S,E,E,=82.3) for females, the predicted VO_2 would be underestimated than the actual values in male subjects. Standard error of the estimate by simple linear regression was larger as the load of exercise became heavier ranging from 260 to 400ml/min for males from 80 to 190ml/min for females.
|