Abstract
Human musculoskeletal system in the upper limbs, which consists of antagonistic pair of mono-articular muscle and bi-articular muscle, is a redundant system. Therefore, great numbers of combinations of the muscle activity level are avail- able during upper limbs movement in the muscle recruitment strategy. In this paper, we derived the preferred directions (PD) that lead to maximal EMG activity from the torque plain (Te. Ts) between the elbow torque and the shoulder torque, and revealed the strategy of muscle recruitment. Finally, we simulated the muscle activity pattern from the elbow torque and the shoulder torque using PD during reaching movement and compared with actual electromyography (EMG). The simulation results indicated that muscle recruitment pattern was different depended on directions of reaching motion.
