This study was aimed to elucidate the relationship between combinations of treadmill speed-grade and oxygen consumption(Vo2). Twenty athetic and 20 non-athletic male college students aged 19-24yr were employed to exercise on a treadmill using 4 speeds(4.02, 5.47, 6.76 and 8.05km/h) and 5 grades(0, 8, 12, 16 and 20%). A fixed speed was selected for each session with the grade increased every 3 min. The Vo2, heart rate, stride frequency and stride length were measured during the last min of each 3-min stage. Vo2increased linearly with increasing speed and grade showing significant multiple correlations in nonathletes(Vo2=3.64x+0.831y+0.031xy-7.03, R=0.98, P<0.01) and athletes(Vo2=3.48x+0.324y+0.112xy-5.74, R=0.99, P<0.01). Stride frequency and length tended to increase with increasing speed except for the transition from walking to runnig at 8.05Km/h at which the stride frequency ran up much higher with the stride length getting lower than at 6.76Km/h. Heart rate increased linearly with increasing Vo2. The rate of increase was higher during walking than during running. These results indicate that athletes have higher rate of increase in Vo2than nonathletes at near-maximal exercise and may be used as a guideline in predicting maximum oxygen comsumption and in prescribing exercise intensity.
Athletes* ; Heart Rate ; Humans ; Male ; Oxygen Consumption* ; Oxygen* ; Running ; Walking