Motor module variability and distinctness. A: a 2-dimensional (i.e., 2 muscles) example of motor module variability and distinctness calculation. Left: colored bars for each muscle weighting represent the contribution of each muscle within a module over each of the 100 different resampled module extractions. Black bars indicate the mean across all resampled extractions. Right: each point in a cluster represents 1 of the 100 resampled motor modules as depicted on left. Motor module variability (Wvar) is defined as the radius encompassing 95% of the resampled points (dashed circle), and motor module distinctness (Wdis) is the average distance between each cluster (solid line). B and C: motor module variability and distinctness did not differ between control (C; n = 16), nonparetic (N; n = 9), and paretic legs (P; n = 9) in either walking (top) or reactive balance (middle). However, in all legs, the motor modules that were shared across the two behaviors exhibited less variability and were more distinct than those that were recruited in only one of the behaviors (bottom). *P < 0.05; #P < 0.1. Musc., muscle.