Effects of Narrow- Vs. Wide-Pulse Neuromuscular Electrical Stimulation Training on Functional Performance.

Espeit, L, Rozand, V, Gravholt, A, Ravel, A, Gondin, J, Millet, GY, Maffiuletti, NA, and Lapole, T. Effects of narrow- vs. wide-pulse neuromuscular electrical stimulation training on functional performance. J Strength Cond Res XX(X): 000-000, 2026-Neuromuscular electrical stimulation (NMES) training has been shown to improve maximal isometric strength but inconsistent effects have been reported on dynamic/functional outcomes. Inconsistencies have been attributed to the general training setup (isometric mode) and to the unphysiological motor unit recruitment pattern of NMES. As pulse duration could modify motor unit recruitment, the aim of the present study was to compare the effects of NMES training with narrow vs. wide pulses on explosive and isokinetic strength, jumping performance, and fatigability. Thirty-six healthy men were randomly allocated to a control group or 1 of 2 NMES training groups, who underwent a 6-week NMES program. Neuromuscular electrical stimulation with narrow (0.2 ms) or wide (1 ms) pulses was applied to the quadriceps muscle with a stimulation frequency of 50 Hz and at the maximal tolerable current intensity. PRE- and POST-training measurements included explosive strength (early and late rate of torque development [RTD]), isokinetic strength (concentric at 60°·s-1 and 180°·s-1, eccentric at -60°·s-1), countermovement jump (CMJ) performance and fatigability (fatigue index during repeated maximal concentric contractions). The effects of NMES training were similar for the 2 training groups. Late- but not early-phase RTD increased at POST (p < 0.05). Isokinetic strength increased at POST (p < 0.05) at all angular velocities. No changes were observed for CMJ performance and fatigue index. In conclusion, 6 weeks of NMES with narrow and wide pulses induced similar improvements in explosive and isokinetic strength but failed to improve jumping performance and fatigability in healthy men.