Electrical Stimulation
Electrical stimulation can be used for both pain relief also known as electroanalgesia or for motor contraction and strengthening.
Pain relief or electroanalgesia is the most common use of therapeutic electricity. The use of therapeutic electricity for analgesia is often referred to as transcutaneous electrical nerve stimulation or TENS, however, all forms of therapeutic electricity that do not use implanted or needle electrodes are transcutaneous and many forms stimulate nerves. Three types of stimulation are used for pain relief. They consist of conventional which is also known as TENS, low-frequency (motor level), and noxious stimulation.
There are two basic mechanisms proposed to explain the effects of using estim for pain relief, the gait theory and the endogenous opiod theory.
Conventional (high rate) TENS is thought to relieve pain by activating the “gating mechanism”. The parameters of conventional tens preferentially stimulate large diameter A delta fibers which have an inhibitory effect on the transmission of pain at the spinal cord level. This type of electrical stimulation only works when it is on the patient, so it doesn't appear to have long lasting effects. There may also be some effect on the endogenous opiate system which would allow for pain relief.
Low rate (motor) TENS and noxious stimulation are thought to relieve pain by activating the endogenous opiate system, releasing opioids and thus decreasing pain. This method will give longer lasting pain relief for 4-5 hours post treatment.
Biphasic and Russian currents are what you want to use in order to contract or strengthen a muscle.