Figure 1. Definition of thorax and radius segment coordinate systems, wrist joint center calculation, ball midpoint calculation and markers. C7: 7th cervical vertebrae; T10: 10th thoracic vertebrae; CLAV: Clavicle; STRN: Sternum; RELB: Right elbow; RWRA: Wrist thumb side; RWRB: Wrist small finger side of the upper body model.