Figure 5. Thumb adduction force and angle - time histories and EMG signals of test and reference contractions obtained for Protocol 2 during voluntary contraction.

For the test contractions, peak force (F_peak) was measured during the stretch phase, and isometric force (F_iso), EMG, and interpolated twitch force (ITF) were measured during the final isometric phase for the comparison with the corresponding values obtained from the isometric reference contractions. After deactivation of the muscle, passive force (F_passive) was measured. Also, purely passive forces were measured for stretch contractions of the completely relaxed muscle (a stretch contraction over 30 deg stretch at 10 deg s⁻¹ is presented).