The evaluation of energy cost of effort and changes of centre of mass (COM) during race walking at starting speed after improving the length of lower extremities.

The purpose of the study was to evaluate the influence of extremities length improvement in the form of special shoe orthoses on the walking energy cost of the leading Polish representative in race walking. Before a proper study, the aerobic capacity of the subject was evaluated. The test consisted of two walking efforts performed on a mechanical treadmill. The subject was walking for 12 minutes with shoe orthoses at constant speed (12 km/h) and then the rest phase allowed for the total covering of the oxygen debt. Then the trial was repeated without orthoses. Simultaneously with measuring physiological variables, there was made 3D recording of the athlete's movements on the treadmill applying the Vicon system. There were chosen vertical oscillations of the body center of gravity and work of the subject's system of motion connected with kinetic and potential energy changes regarding the movements of COM during gait. The energy cost of walking at speed related to anaerobic threshold (starting) using shoe orthoses was slightly lower compared to energy expenditure during gait without improvement. No significant differences were noticed in the range of summary vertical COM oscillations during walking in both variants of the measurement. However, considerable asymmetries appeared in the value of COM kinetic energy changes that were lower for the right leg. This testifies to a strongly fixed asymmetrical scheme of individual athlete's technique.