Effect of running velocity on external mechanical power output

The mechanical power output and work done in running were measured for eight athletic runners by means of a strain gauge platform and 16mm cine camera. The angle between the line connecting the centre of gravity of the body with the foot on the ground and the horizontal line was about 110 degrees at the moment of foot contact with the ground, independent of running velocity. The external work by velocity change (Wf) increased curvilinearly with the running velocity up to about 630 Joule kg-1 at maximum velocity. The mechanical power output per body weight in forward direction (Pf) increased as the 2nd power of the running velocity and the following equation was obtained Pf=0·436V2·01 f where Pf was expressed in Wkg-1 and Vf in ms-1. At the velocity higher than 6ms-1, the mechanical power by forward velocity changes (Pf) increased gradually greater than that against gravity (Pv) but at the lower velocity than 5ms-1 Pf was always less than Pv.