Perhaps the most common use of transcutaneous electrical nerve stimulation (TENS) is to reduce pain. TENS stimulates nerves which helps to distract your brain's sensation of pain. This distraction helps to decrease both chronic and acute pain.
Muscle spasm, both chronic and right after an injury, can cause pain and can reduce concentration and the ability to work. TENS is a research-supported method to relax these muscles and improve movement.
There is some evidence to suggest that using TENS helps speed up the healing process. This can be due to reduced inflammation or it can be from a reduced fear of movement.
Do not place TENS electrodes over numb areas; TENS units require the nerve signals are intact to properly work.
Do not place over broken skin or open wounds.
Adjust the intensity to a slightly uncomfortable level and then decrease the intensity until comfortable. TENS should feel kind of like your hand or foot fell asleep, but it should feel comfortable.
Experiment with the settings, you will find the "ideal" setting through trial and error and you will find that it is different from others.
Many begin with a medium pulse frequency of 80-100Hz and duration 100-200 microseconds to begin.
Start with 20 minutes of use the first time, and adjust up or down as needed.