The Effect of Extreme Change in Step Length on Oxygen Uptake during Walking

Abstract

The purpose of this study was to examine the effect of extreme changes in step length on the oxygen uptake at fixed speeds, i.e., 60, 80, 100 and 120m/min walking, respectively. The subjects were eight healthy active female students who performed treadmill walking for 18 min with the three different step lengths, i.e., freely chosen (FCSL), as short as possible (SSL) and as long as possible (LSL) at each speed. During each walking trial, the step lengths changed every 6 min. Determinations of oxygen uptake and step frequency were made during 5-6, 11-12 and 17-18 min. The mean % VO₂max and oxygen uptake per 100meter (ml/kg/100m) were 22.4-54.3 and 18.5-22.1 for FCSL, 40.5-61.4 and 33.3-24.9 for SSL and 48.8-67.8 and 39.4-27.5 for LSL at all speeds, respectively. The oxygen uptake per 100meter during walkings with the SSL and the LSL were significantly greater (p<0.05) than the FCSL at each speed. However, there were no significantly differences between walking with the SSL and the LSL. The mean increases in oxygen uptake per 100meter were 14.8-2.8ml/kg/100m for SSL and 20.9-5.4ml/kg/100m for LSL. Both extreme increase and decrease in step length from the freely chosen step length caused increase in oxygen uptake. These resuits indicate that extreme changes in step length affected walking efficiency.