Fig. 1

Arrangement of surface electromyography (sEMG) electrodes. The G1 electrode position is 2 cm distal to the insertion of the medial gastrocnemius muscle (MG) into the Achilles tendon and is used for both sEMG methods (bipolar and monopolar). In the bipolar sEMG, the G2 electrode (BG2) is placed 3 cm distal to G1. In the monopolar sEMG, the G2 electrode (MG2) is placed 3 cm medially and 2 cm superiorly to medial malleolus (MM) and over the Achilles tendon. The reference electrode (R) of both methods is placed anterior over the tibial bone at a distance between the stimulus site and G1 electrode (dashed circle).The stimulating site (S) is approximately 1 cm lateral to the popliteal crease mid-point (PCM)