The surface electromyography was recorded from the FCR of the dominant arm with adhesive electrodes (3M Red Dot TM). Before attaching the electrodes, the skin was shaved when necessary and cleaned with a solution of alcohol, ether, and acetone to reduce the impedance at the skin-electrode interface. The electrodes were placed over the muscle belly in a bipolar configuration at the proximal third of the forearm, with an inter-electrode (centre to centre) distance of 2 cm. The location of the electrodes placed on the muscle belly was determined by palpation and ultrasound imaging (DP-6900Vet; Shenzhen Mindray Bio-Medical Electronics), using a 6-cm width linear-array probe (7.5-MHz; 75L60EA, Shenzhen Mindray Bio-Medical Electronics), during wrist flexion, extension and abduction. The reference electrode was placed over the olecranon. The EMG signal was amplified (200×) and band-pass filtered (10–1000 Hz) prior to A/D sampling at 4 kHz (Power 1401, 16-bit resolution, Cambridge Electronic Design, UK).