Neuromuscular Electrical Stimulation
(NMES) Questions & Answers
NMES Definition - ANSWERS-The use of electrical stimulation for activation of muscles
through stimulation of the intact peripheral nerve.
-Used to enhance maximal force production in a voluntary muscle contraction when the
muscle's performance is impaired.
Normal Voluntary Muscle Contractions - ANSWERS-An individual motor neuron fires
"all or none"
-As the rate of motor neurons firing increases, so does the intensity of the muscle
contraction
-A motor unit (muscle fibers activated by a single motor neuron) contracts as a single
entity
-As the firing rate increases, the motor unit will contract harder
Voluntary Muscle Contractions - ANSWERS-During voluntary activity, the brain
activates SMALL motor unit first; then activates larger motor unit to produce a stronger
contraction if necessary.
Electrically Stimulated Muscle Contractions - ANSWERS-Large motor units contract first
-Motor neurons innervating large motor units have large diameters which are easily
excited by the ES
-NMES recruits motor units in reverse order (large then small) to voluntary muscle
contractions.
NMES Waveform - ANSWERSEach stimulator will have some variation of a pulse
alternating current or biphasic waveform
NMES Intensity - ANSWERS-Desired treatment outcome is always to achieve a motor
response-never sensory
-Treatment goal: to obtain a strong quality muscle contraction
