To begin, instruct the participant to sit in the experimental chair with their elbows resting on the arms of the chair and bent to allow the wrist or hand to rest comfortably on the desk workplace. Adjust the height of the chair and desk workplace as needed. Clean the skin over the abductor pollicis brevis or APB, first dorsal interosseous, or FDI and the ulnar styloid process, using a mildly abrasive cream placed on a round cotton pad.
Wipe away any residue using an alcohol prep pad. For each muscle, place one disposable silver silver chloride adhesive electrode over the muscle belly. Place a second electrode on a nearby bony landmark as a reference.
Finally, place one additional silver silver chloride adhesive electrode on the ulnar styloid process to serve as a ground. Connect each pair of electrodes and the ground to the electromyography or EMG amplifier and data acquisition system. Use channel one for the first dorsal interosseous and channel two for the abductor pollicis brevis.
