A comparison of the energy expediture during positive and negative grade running
The purpose of this study was to compare the energy expenditure during. positive and negative grade running. This comparison ,.,as expressed as a ratio utilizing net percent difference from the horizontal for both downgrade andupgrade values (m1/kg-min). A group of ten highly conditioned runners was tested on three separate treadmill runs utilizing a +6% grade, 0% grade, and a –6% grade. All runs were of a seven minute duration at an average speed of 200 m/min. Variables measured were heart rate, oxygen consumption, leg length, stride length, and step frequency. It was found that the fractional utilization of the aerobic capacity varied from44% (-6% grade) to 78% (+6% grade). Energy requirements increased 40% (+6% grade) and decreased 27% (-6% grade) from horizontal values. The resultant positive:negative work ratio was 1.92:1. Correlations among -variables fluctuated from slight to moderate with the most significant being a high positive correlation between energy expenditure and step frequency.