Fig. 1:

(A) Functional tasks performed by participants, including a functional pull (top) and axilla wash (bottom). Start/finish (left) and target (right) positions for each task are shown. For the functional pull, participants were seated at a table (height = 0.775m) and pulled against 2.72kg (6lb) resistance from a pulley system. The functional pull task started with the arm forward flexed a distance of 80% of the subject’s forearm length (length was marked on the table) and handle from a weight machine, pull the handle until the arm is in neutral flexion (target), then finish by returning to the start position. For the axilla wash, which is an unloaded task, the participant remained seated but the table was removed. The task started with the elbow extended and arm in neutral, resting quietly at the side. Participants then reached across the torso to touch the lateral aspect of the contralateral shoulder (target), then finished the task by returning to the starting position, with the arm resting quietly at the side in neutral posture. (B) Anatomical locations of retro-reflective markers used with motion capture (pink spheres). Twelve markers were placed at locations including: C7: 7^th cervical vertebra; SC: ventral aspect of the sternoclavicular joint; XP: xiphoid process; AA: lateral aspect of acromial angle of scapula; UA: upper arm, mid-length; LE: lateral epicondyle of humerus; ME: medial epicondyle of humerus; FA: forearm, mid-length; RS: styloid process of radius; US: styloid process of ulna; 5MP: 5^th metacarpophalangeal joint; 2MP: 2^nd metacarpophalangeal joint. An additional marker (not shown) was affixed to the top of the handle used for the functional pull task.