PHASE DIFFERENCE BETWEEN FORWARD SWINGS OF

In previous observations of the lower extremity movement in long distance running, a seemingly ineffective action, was noticed. It was observed that the upper leg swung to its most forward angle once, then returned backward before the lower leg swung to its most forward angle, prior to the foot touching the floor (Kawai & Hiki, 1999). In this study, the relationship between the phase difference and the amount of work around the hip joint was investigated, by using a computer simulation, in order to determine the meaning of the phase difference. From the results, it was reasoned that the upper leg swung forward in the advanced phase before the lower leg. This was in order to decelerate the mass of the lower leg smoothly, by raising the knee and to minimize the change of work for decelerating the whole leg before the foot touching the floor