Repetitive stress and Repetitive Strain Injuries (RSI) are, in my opinion, the most common cause of arm and hand pain. Treatment of these injuries are a specialty in my Neuromuscular Therapy center near Boston. This post is part of a series on the causes of arm and hand pain. If  you missed the beginning, go back to my Checklist of Causes.

When we move, our muscles work by contracting and relaxing, shortening then lengthening. Muscles work in opposing pairs. As one muscle contracts, the opposite muscles relax. That’s how we get movement. For instance, if the biceps contract to bend the arm at the elbow, the triceps must lengthen. If they both contract at the same time movement stops. That happens either for stability or because of diseases such as cerebral palsy. Every time a muscle contracts the blood flow is reduced by about 20%. When it relaxes, blood flows normally. Contracting and relaxing pumps blood in and waste out, keeping the muscles healthy and happily working for you.

Another thing that’s important to understand about muscles is that every time they do work they burn metabolic fuel. Every time you burn fuel you get waste products. Metabolic waste goes into the fluids around the muscles. If the muscles are constantly contracted, the waste can’t get out, so it gets stored in the tissue as acids (like lactic acid). With repetitive use, waste products build up and the blood can’t deliver enough nutrients and oxygen to keep the muscles healthy. Both cause toxic conditions and pain. Over time and with repetitive use the cells of the tissue involved become unhealthy, both because it can’t heal without getting enough blood and because the cells begin to break down in the toxic acidic environment in which they are trying to live.

In order to get rid of the pain and rebuild healthy muscles, it is essential to get blood flowing efficiently through them. Stretching lengthens them and allows more blood through. (Hold for two seconds max and repeat 10 times. This Active Isolated Stretching protocol is especially important for repetitive stress.) Stimulation like short applications of ice or heat increases blood and lymph flow in the capillary beds under the skin. Giving the muscles some time off reduces stress. Add some deep belly breathing. Relaxation has it’s place.

A third thing to remember about muscles is that when one muscle or group of muscles is chronically tight, the muscles that oppose them will be weak. Weakened muscles are more easily injured and cause a muscle imbalance.  That leads to muscle compensation and eventually  joint problems. The imbalance puts a strain on the wrist, thumb and elbow joints, tightening the muscles that move them, straining the ligaments that hold them together and compressing the nerves between them.

Repetitive stress on arm and hand muscles is common in our computer oriented culture. Taking frequent breaks, finding different ways of working (i.e. switching mouse hands or fingers, working in different positions), drinking enough water, watching posture to prevent tensing shoulder and chest muscles, stretching daily, getting aerobic activity mid-day, reducing stress and getting enough sleep are all preventative measures for avoiding more serious injuries.