Fig. 4From: Increased gait variability during robot-assisted walking is accompanied by increased sensorimotor brain activity in healthy peopleNormalized vertical ground reaction force (GRF; mean ± SD) during the stance phase of unassisted walking (UAW) and robot-assisted walking (RAW). In Additional file 1, normalized vertical GRF during the stance phase of UAW (Figure S1) and RAW (Figure S2) are presented for each individual participant Back to article page