Relation between the thigh-calf contact force and the posture of an upper body at squatting

It is important to consider the thigh-calf contact force to analyze the kinetics of a lower limb during deep knee flexion, however, the measured forces have varied very much and difficult to understand systematically. In this study, we considered that the thigh-calf contact force might be estimated by considering not only the individual difference but also the joint angles or the posture of an upper body, and measured the forces and introduced the estimating equation. The test subjects were 6 healthy male, and measured the joint angles and thigh-calf contact force, and performed a multiple regression analysis. As a result, equations to estimate thigh-calf contact force using joint angles and the individual parameter were introduced. The average error of estimation was 0.11BW and the maximum was 0.33BW. It was clearly indicated that the postures of the upper body effected to the thigh-calf contact force.