Understanding Therapeutic Modalities

​Series 3 - TENS Transcutaneous Electrical Nerve Stimulators

Physical Principles
An electrical current applied to nerve tissue at a sufficient intensity and duration to reach that tissue’s excitability threshold will result in a firing of that nerve.
As current intensity or duration is increased the threshold will be reach first for sensory fibers, then for motor fibers, and then for pain fibers. It is possible to produce different physiological responses by adjusting the treatment parameters.

​Pain Modulation

​Gate Control - Electrical Stimulation of sensory nerves diminishes the awareness of painful stimuli. As long as the stimulation is causing the sensory nerves to fire, the gate to pain should be closed

​Descending Pain Control - Intense stimulation of the smaller pain fibers causes stimulation of descending neurons, which then affect the transmission of pain information by closing the gate at the spinal cord level.

​Opiate Pain Control Theory - Electrical stimulation of sensory nerves stimulates the release of endorphins. Pain modulation is caused by applying electrical current close to the site of pain or to acupuncture or trigger points both local to and distant from the pain area.

​Muscle Contraction

​Muscle Pumping - This type of contraction is used to help stimulate circulation by pumping fluid and blood through the venous and lymphatic channels back to the heart.

Muscle Strengthening - For the best results the athlete should combine this electrically induced tetanic contraction with maximal active contraction against some resistance.

Retardation of Atrophy - Electrically induced muscle contraction can be used to minimize atrophy and loss of muscle function that typically occurs with immobilization after injury.

​Muscle Reeducation - Muscular inhibition after surgery or injury can be reduced by electrically stimulated a muscle. The athlete should watch and feel the contraction and attempt to initiate a voluntary contraction.

​References
Arnheim’s Principles of Athletic Training - A Competency Based Approach, William E. Prentice, 12 Edition, 2006, pg 416-420

Upcoming - Series 4 - Massage