Muscle Stimulation

Written by Phil Pask

Neuromuscular Electrical Stimulation (NMES)

Neuromuscular electrical stimulation (NMES) can be a beneficial supplement to traditional forms of therapy in the patient who finds a muscle function is reduced either by inhibition (post injury) or even the period post-surgery (e.g Knee). This inhibition may demonstrate itself as either weakness, with or without loss of bulk (atrophy), or even the lack of ability to “switch” the muscle on despite the patients best efforts!

We can use a simple non-invasive, no painful, neuromuscular stimulator such as “Compex” or Neuro Trac [Nuerotec] devices to override the patients inhibitions and produce a muscle contraction. A specific muscle or group of muscles can be targeted by placing simple “sticky” electrodes at certain points over a muscle to gain a variety of different muscle effects by “exciting“ that muscle.

The patient can “passively” let the muscle contract through the stimulus or later on in the rehab process can actively join in with the contraction.

A great example is the rehabilitation of most knee conditions where one of the quadriceps muscles, the Vastu Medialis, can atrophy very quickly indeed. You will recognise this muscle as the “tear drop” shaped muscle on the inside of the knee. By stimulating this muscle very soon post injury or post operatively you can not only keep the muscle firing but can maintain some of its bulk. Later on in the rehab you can perform simple exercises such as step ups or squats along with the muscle stimulation to make quicker and better gains in muscle strength and function.

The evidence

There are lots of studies out there but a couple of interest can be found below:

It has been reported that after knee joint replacement, a patient group who engaged in highly intensive activation of the quadriceps muscle using electrical stimulation produced better results for strength and muscle activation compared with a control group.29 Comparable studies conducted after anterior cruciate ligament (ACL) reconstruction produced.
The American Journal of Sports Medicine, Vol. XX, No. X

The primary objectives of rehabilitation after ACL reconstruction are to reduce inflammation, regain neuromuscular strength and functional performance, recover normal range of motion, and reintegrate the patient to everyday activities. Studies have shown that the activation  attern of the quadriceps and hamstring muscles as well as restoration of proprioception play an important role in rehabilitation after ACL surgery. A recent review concluded that rehabilitation training with NMES superimposed on voluntary contraction was better than either NMES or voluntary contraction practiced separately.
Sports Med. 2008;38:161-177