PROBLEM TO BE SOLVED: To obtain reaction acting on a subject's foot when the subject moves on a force plate while placing his stick on random places on the force plate.SOLUTION: The floor reaction measurement system comprises a force plate, a stick with a load sensor at a tip, a means to obtain location and position of the stick, a means to obtain floor reaction F1(F1,F1,F1) and location P1(x,y) when the subject moves on a tread with the stick, a means to obtain reaction F2(F2,F2,F2) acting on the stick and location P2(x,y), a means to obtain reaction F3(F3,F3,F3) acting on the subject's foot from floor reaction F1(F1,F1,F1) and reaction F2(F2,F2,F2) of the stick, and a means to obtain location P3(x,y) on the tread on which reaction F3 of the foot acts, from floor reaction F1 and location P1, reaction F2 and location P2 of the stick, and reaction F3 of the foot.
