Aerobic requirements of overground versus treadmill running

Abstract

There is general agreement that the O2 demand of level running is similar for both the treadmill (TM) and overground situations at speeds under 260 m .cntdot. min-1. However, controversy exists with regard to inclined running. The prevailing view, represented by the ACSM [American College of Sports Medicine] prediction formulas, is that overground hill running is theoretically more costly than inclined treadmill running. This study was designed to investigate the problem from an empirical standpoint. Male subjects (7) performed overground and TM running at 2 grades (0 and 5.7%) over a range of speeds between 136-286 m .cntdot. min-1. For the outdoor trials, subjects covered a distance of 950 m at a constant pace, and expired gas was collected over the last 150 m. Matching trials were then performed on the treadmill at the same speed and % grade. Regression lines were calculated for speed vs. O2 consumption (.ovrhdot.VO2). A 2 .times. 3 .times. 2 ANOVA [analyses of variance] revealed that the differences between mean values for .ovrhdot.VO2 for level TM running vs. level overground running and grade TM running vs. grade overground running were not statistically significant (0.10 < P < 0.25). Therefore, it would appear that measurements of .ovrhdot.VO2 obtained during level and inclined TM running are valid when applied to the overground situation in the range of speeds considered in this study.