Figure 2. Thumb adduction force and angle - time histories of test and reference contractions obtained for Protocol 1 during electrical stimulation.

For the test contractions, peak force (F_peak) was measured during the stretch phase. Isometric force (F_iso) was measured during the final, steady-state isometric phase for comparisons with the corresponding values obtained from the isometric reference contractions and used to assess force enhancement (FE). After deactivation of the muscle, passive force (F_passive) was measured. Also, purely passive forces were measured for stretch contractions of the deactivated muscle (a stretch contraction over 30 deg stretch at 10 deg s⁻¹ is presented).