Neuromuscular Electrical Stimulation–Induced Resistance Training After SCI: A Review of the Dudley Protocol

Abstract

Background: Neuromuscular electrical stimulation (NMES), often referred to as functional electrical stimulation (FES), has been used to activate paralyzed skeletal muscle in people with spinal cord injury (SCI). The goal of NMES has been to reverse some of the dramatic losses in skeletal muscle mass, to stimulate functional improvements in people with incomplete paralysis, and to produce some of the health benefits associated with exercise. Objective: The purpose of this brief review is to describe a quantifiable resistance training form of NMES developed by Gary A. Dudley. Methods: People with motor complete SCI were first tested to confirm that an NMES-induced muscle contraction of the quadriceps muscle could be achieved. The contraction stimulus consisted of biphasic pulses at 35 Hz performed with increasing current up to what was needed to produce full knee extension. Four sets of 10 knee extensions were elicited, if possible. Training occurred biweekly for 3 to 6 months, with ankle weights being increased up to an added weight of 9.1 kg if the 40 repetitions could be performed successfully for 2 sessions. Results: Many participants have performed this protocol without adverse events, and all participants showed progression in the number of repetitions and/or the amount of weight lifted. Large increases in muscle mass occur, averaging 30% to 40%. Additional physiological adaptations to stimulated muscle have also been reported. Conclusions: These results demonstrate that the affected skeletal muscle after SCI responds robustly to progressive resistance training many years after injury. Future work with NMES should determine whether gains in lean mass translate to improved health, function, and quality of life.

Retained differentiation capacity of human skeletal muscle satellite cells from spinal cord-injured individuals

“…Different protocols of functional electrical stimulation mimic different types of exercise (Fornusek and Davis ; Bickel et al. ). Both endurance and resistance training lead to an increase in satellite cell number, while resistance training also leads to an increase in myonuclear number (Bruusgaard et al.…”

“…Electrical stimulation coupled with exercise improves the metabolic characteristics of skeletal muscle in spinal cord-injured individuals (Hjeltnes et al 1998;Gorgey et al 2017) and may be used as a potential activator of skeletal muscle regenerative machinery (Kern and Carraro 2014). Different protocols of functional electrical stimulation mimic different types of exercise (Fornusek and Davis 2008;Bickel et al 2015). Both endurance and resistance training lead to an increase in satellite cell number, while resistance training also leads to an increase in myonuclear number (Bruusgaard et al 2010;Kurosaka et al 2012).…”

A feasibility pilot using telehealth videoconference monitoring of home-based NMES resistance training in persons with spinal cord injury

“…Electrically evoked resistance training (RT) using surface neuromuscular electrical stimulation (NMES), (Dudley's protocol), has proven to be an effective intervention to evoke muscle hypertrophy in persons with SCI. [7][8][9][10][11][12] Several studies indicated that RT, twice weekly from 8 to 16 weeks, increased muscle size significantly compared to pretraining cross-sectional areas (CSAs). [7][8][9][10][11][12] Dudley et al 7 showed that 8 weeks of twice-weekly NMES-RT restored knee extensor muscle size to 75% of what it was 6 weeks post-SCI.…”

Endurance neuromuscular electrical stimulation training improves skeletal muscle oxidative capacity in individuals with motor‐complete spinal cord injury

“…Neuromuscular electrical stimulation (NMES) has been used extensively in rehabilitation settings, and numerous studies have demonstrated its efficacy in promoting adaptive responses in SCI patients. For example, NMES resistance exercise training induces skeletal muscle hypertrophy and may reduce IMF . A previous study reported that resistance NMES training also resulted in significant improvements in in‐vivo skeletal muscle oxidative capacity .…”

“…For example, NMES resistance exercise training induces skeletal muscle hypertrophy and may reduce IMF. [20][21][22][23] A previous study reported that resistance NMES training also resulted in significant improvements in in-vivo skeletal muscle oxidative capacity. 24 These improvements averaged 25% and, although significant, were not enough to bring skeletal muscle oxidative capacity to near able-bodied levels.…”