One of the most frequently asked questions I get from patients is, “how does acupuncture work?” While Chinese medicine, and therefore acupuncture, is frequently (and perhaps erroneously) labeled as a ‘metaphysical’ or ‘energy-based’ medicine, there is enough evidence available today that allows us to present a different point of view–using more commonly understood Western scientific concepts. To those attached to the ‘energy-based’ model, I acknowledge that there is a multiplicity of points of view when it comes to acupuncture’s mechanism of action. I also acknowledge that some of the commonly held beliefs in the West are likely due to mistranslation and misinterpretation of traditional Chinese texts. Therefore, I will use a series of articles to explain some of the ways in which acupuncture can bring about a physiological response, and therefore create a therapeutic action, from a Western physiological point of view. Part one in this series will describe the use of acupuncture motor points for the treatment of pain and musculoskeletal injuries.
Muscle motor points are specific acupuncture points, which have a direct effect on muscle function. They directly activate the part of the nervous system responsible for regulating muscle strength and tension. As the name suggests, motor points affect motor units. A motor unit consists of nerve fibers that carry information from the central nervous system (located in the brain and spinal cord) to the muscles, and they tell the muscles what to do (contract or relax). There are upper motor neurons and lower motor neurons, which communicate as part of a two-way system. The upper motor neuron in the brain sends a signal to the lower motor neuron, which travels through the torso and extremities to connect with, and communicate directly to, the muscles. The upper motor neuron can send a signal to either contract or relax a muscle, and the lower motor neuron receives that signal and delivers it directly to the muscle fibers. In reciprocal fashion, the lower motor neuron relays information from the muscle to the upper motor neuron and communicates information about the muscle’s state—is it relaxed or contracted.
Injuries or other problems involving a motor unit prevent the nerve signal from communicating to the muscle properly. This can result in muscle weakness, decreased size and tone, involuntary twitches or muscle spasm, and decreased or absent muscle reflex. Absent or reduced motor neuron function can be due to a number of reasons–postural imbalances, acute injury, scar tissue from and old injury, joint degeneration, and misalignment or degeneration of vertebrae in the spine. Weakness in muscles may also occur if there is an injury to the upper motor neuron in the brain, which occurs in cases such as traumatic head injury or stroke. However, it is more common that damage to the upper motor neuron prevents a signal from being sent to stop muscle contraction. This results in constant spasm or spasticity of certain muscles.
The motor points are located at the central belly of the muscle where the lower motor nerve connects to the muscle fibers. This region is the most bio-electrically excitable area of the muscle. The application of an electrical stimulation to the motor point can effect the nerves, causing the muscle to either contract and strengthen if it is weak, or stop contracting and relax if it is tight and in spasm. Because an acupuncture needle is incredibly thin and made from an electrically conductive metal, it is the perfect tool to precisely and effectively target and stimulate the specific point of motor nerve innervation. The excitatory reaction created by an acupuncture needle at the motor junction, where the nerve connects with the muscle fibers, stimulates receptors in the muscle. While not required for the therapeutic effect, it is not uncommon for the practitioner to see and the patient to experience a muscle twitch (or fasciculation). This is a signal that the muscle is resetting to function properly.
Because the motor points have the greatest influence on electrical or nerve activity, they also have the greatest impact on pain and dysfunction of that muscle. The major muscles of the limbs and trunk have large motor units that can affect many muscle cells and fibers. This makes the treatment of motor points more effective than more commonly used trigger points. Motor points have the added benefit of not only treating pain, but also effecting muscle function. As such, they can be used to strengthen or relax muscles and help to change postural imbalances, which can be at the root of many painful musculoskeletal conditions.
The identification of motor points and their application in the Sports Medicine Acupuncture® system has revolutionized the time-honored practiced of acupuncture, bringing it into the 21st century as a scientifically verifiable modality. Used in conjunction with traditional acupuncture points, postural assessment, and corrective exercises, the treatment of motor points enhances the short and long term effectiveness of acupuncture treatments for musculoskeletal pain and dysfunction.