The Effects of Selective Muscle Weakness on Muscle Coordination in the Human Arm

Figure 3

Average tuning curves and muscle activation pattern as a function of target force direction, for the 2D protocol for a single subject in pre- and postblock (blue and red, resp.). The tuning areas, but not many tuning directions, were altered following BRA motor point block. The coordinate system for force directions is indicated at the top right corner. The EMG of each muscle was normalized by the maximum EMG of the muscle in the entire dataset recorded from the subject. Muscle names are indicated in an abbreviated form (BRD: brachioradialis; BIm: short head of biceps brachii; TRIlong and TRIlat: long and lateral heads of triceps brachii, resp. AD, MD, and PD: anterior, medial, and posterial fibers of deltoid, resp. PECTclav: clavicular fibers of pectoralis major: BILat: long head of biceps brachii; ANC: anconeus; PRO: pronator teres; SUP: supinator; BRA: brachialis).