EMS mechanisms of action - motor nerves and muscle
Electrical muscle stimulation: to improve circulation, re-establish function, prevent atrophy and strengthen muscle
Electrical Muscle Stimulation (EMS)
Purpose
Stimulation of motor nerves of voluntary muscle
Stimulation of motor nerves of involuntary muscle
Direct stimulation of voluntary muscle fibre
Direct stimulation of involuntary muscle fibre
For improved circulation
For muscle strengthening
To re-engage and re-train motor nerve neural pathways
How it works
Electrical stimulation induces an isometric muscle contraction; i.e. a contraction that neither lengthens nor shortens the muscle. To achieve this:
Electrodes must be placed accurately
Intensity must be above muscle contraction threshold
The signal pulses ON (for between 6 and 12 seconds) and then OFF (for between 12 and 24 seconds)
While the signal is ON the muscle is contracted and held in contraction
When the pulse is OFF the muscle contraction is released and the muscle relaxes
The relaxation period should be approximately twice as long as the contraction period
Tissue repair
Mild muscle stimulation helps the circulatory system to function normally, resulting in:
Improved overall circulation
Improved local blood circulation, oxygen and nutrient availability
Elimination of waste fluid, reduction of swelling and inflammation
Breaking down scar tissue
Maintaining or increasing the range of joint movement
Muscle condition
Stronger muscle stimulation builds muscle strength:
Each muscle contraction slowly develops muscle fibre - just like manual exercise
Actual muscle development is directly proportional to the number and strength of the contractions, over time
Benefits include:
Preventing muscle atrophy
Improving muscle tone and bulk
Protecting joints, ligaments and tendons through improved muscle strength
Increasing stability and balance through improved muscle strength
When manual exercise is not possible, then electrical stimulation is an excellent option.
Functional rehabilitation
When neural pathways are damaged, EMS can act as the source of initiation of the contraction. This is a goal in itself.
Secondly, sometimes the neural pathway memories can be restored with repeated use of EMS.
Electrode placement
Electrodes are placed at the upper insertion (or top) of the muscle and over the motor point of the muscle group to be exercised.
The motor point is the most electrically excitable area of the muscle, where a minimum amount of electrical stimulation will easily excite that portion of the muscle. It is usually located at the centre of the muscle mass, where the motor nerve enters the muscle.
If the motor nerves are denervated, the muscle can be stimulated directly.