Abstract

In race walking competition disqualification occurs regularly, because surface contact is lost. The accuracy of these judgements is often discussed. An investigation was set up in order to determine the time of surface contact. A race walker walked on a treadmill with variable speeds of 5 to 13 km/hr. The double support phase duration showed a sharp decrease with increasing speeds. At high speeds it is almost impossible for the human eye to determine if a subject keeps in contact with the surface. The increase of walking speed was achieved by an increase of the stride length and a proportional increase of the stride frequency. The electromyographic activity of the mm. tibialis anterior, gastrocnemius and vastus lateralis was also investigated and showed a general increase with speed. However, onset of activity changed with increasing speeds. Verf.-Referat