Is defined by the American Physical Therapy Association (APTA) as a skilled intervention that uses a thin needle to penetrate the skin and stimulate underlying myofascial trigger points. There are different approaches to stimulate the tissues; the needle can be left on site for a short period of time (up to 20 minutes) or pistoned in and out of the muscle, causing a local twitch response (LTR) from the trigger point. After the LTR, it has been observed that there is a decrease in concentrations of inflammatory modulators.