Relationship between smoothness of center of gravity and smoothness of lower limb joint torque during walking

-Study using minimum jerk-cost model and minimum torque-change model-

Abstract

Purpose：Using minimum jerk-cost model and minimum torque-change model, we examined the relationship between the smoothness of the center of gravity during walking （center of gravity Cj） and the smoothness of the lower limb joint torque （lower limb joint Cτ）. Methods：We measured the center of gravity Cj and lower limb joint Cτ during walking at a comfortable speed in 10 healthy adult males. Results：The center of gravity Cj and lower limb joint Cτ during the stance phase were positively correlated （r=0.685 p＜0.05）. Furthermore, the waveforms of the two functions were cross-correlated（ CCF=0.77 p＜0.005）. The smoothness of the center of gravity was impaired approximately 30 msec after the smoothness of the lower limb joint torque was impaired. Conclusions：It was suggested that the center of gravity Cj is determined to some extent by the lower limb joint Cτ, and is influenced in a time-series manner approximately 30 msec later.