Neuromuscular electrical stimulation (NMES)

Neuromuscular electrical stimulation stimulates muscle with high-frequency electrical impulses above 60 Hz.^{1Schoenfeld, Science and Development of Muscle Hypertrophy, 2nd ed., p. 87.} In animal studies it produces significant gains in muscle mass within a few sessions.^{1Schoenfeld, Science and Development of Muscle Hypertrophy, 2nd ed., p. 87.} In humans, resistance training remains the main way to build muscle.^{1Schoenfeld, Science and Development of Muscle Hypertrophy, 2nd ed., p. 87.}

In spinal cord injury, NMES activates a single trained muscle.^{2Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 804.} Functional electrical stimulation leg cycling, by contrast, activates up to six muscle groups.^{2Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 804.} Systematic reviews confirm that electrical stimulation increases muscle size or lean mass, though its effect on fat mass is still unclear.^{3Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 808.}

In practice

• Paralyzed muscles can be trained with surface NMES resistance training, using a protocol of 4 sets of 10 repetitions per leg.^{4Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 809.}
• Allow at least 48 hours between sessions to avoid the muscle damage that typically follows activating paralyzed muscle.^{2Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 804.}
• People with spinal cord injury at or above T6 can have a sudden 20 to 40 mm Hg rise in systolic blood pressure during stimulation, so check blood pressure every few minutes during each session.^{5Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 805.}