Fig. 2

Cathode (black) and anode (red) positions for 6 electrode montages (left) with associated recruitment curves (center) and posterior root-muscle reflex response traces elicited by a stimulation intensity of 1.2xRT (right) from a representative participant (P13). Dorsal–ventral umbilicus (DV-U): cathode over T11/T12 with anodes over the umbilicus; dorsal–ventral iliac crests (DV-I): cathode over T11/T12 with anodes over iliac crests; dorsal–ventral paraspinal umbilicus (DV-PU): paraspinal cathodes at T11/12 with anodes over the umbilicus; dorsal–ventral paraspinal iliac crests (DV-PI): paraspinal cathodes at T11/12 with anodes over iliac crests; dorsal-midline caudal (DM-C): cathode over T11/12 with an anode 5 cm caudal; and dorsal-midline rostral (DM-R): cathode over T11/12 with an anode 5 cm rostral. Blue = dominant soleus muscle, red = nondominant soleus muscle, inverted triangles = time of stimulus application. Note the different scales for response traces across montages