Fig. 9. Net work produced at each joint per kg body mass versus acceleration. The slope of regression lines was steepest at the ankle, indicating that the modulation of limb work during accelerations and decelerations occurred primarily at this joint. Work at the hip and MP also had a significant relationships with acceleration but with shallower slopes than at the ankle. The amount of work done at the knee was low and independent of acceleration. Linear regressions are: hip, y=0.095x+0.954, r²=0.035, P<0.001; knee, y=0.021x+0.347, r²=0.05, P=0.256; ankle, y=0.302x+0.024, r²=0.83, P<0.0001; MP, y=-0.08x-0.997, r²=0.39, P<0.001.