Repetitive Motion Injuries: Industrial Workers and Athletes

By Daniel G. Graetzer, Ph.D.
Faculty Member, School of Health Sciences

Repetitive motion injuries (also called repetitive strain injuries or cumulative trauma disorders) are rapidly becoming an epidemic. Tens of thousands of Americans every year develop physical problems related to repetitive motions, such as carpal tunnel syndrome, chronic back pain or other injuries that have the potential to negatively impact nearly every aspect of their lives.

Most of these repetitive motion injuries are often brought about by limited or fine movements performed repeatedly. In fact, repetitive motion injuries are now considered the number one occupational hazard of the information age. They have been around for decades, and healthcare providers have been called upon to treat medical problems such as:

• Carpenter’s and cashier’s elbow
• Dentist’s and fruit picker’s hand
• Mail sorter’s and musician’s fingers
• Meat packer’s and assembly line worker’s shoulder
• Stitcher’s and hairdresser’s wrist

Amateur and professional athletes are often more susceptible to repetitive motion injuries. Often, they compound work-related stress with evening and weekend exercise resulting in tennis players often disabling their elbows, dancers their hips and skiers their knees. Similarly, baseball/softball players can injure their shoulders and most people can suffer back problems.

Working in a modern air-conditioned office may initially seem safer than mining coal, constructing a skyscraper or jackhammering cement. However, the seemingly gentle movements from using a computer keyboard or twisting to answer a telephone often causes more persons to suffer repetitive motion injuries.

As a result, they miss work and may not be able to continue regular participation in the sports that they enjoy. For these people, the shift to more sedentary living results in weight gain and then creates a downward spiral with respect to many degenerative diseases such as heart disease.

What Are Typical Repetitive Motion Injuries?

Some basic upper extremity repetitive motion injuries include:

• Carpal tunnel syndrome – caused by excessive pressure on the segment of the median nerve that runs through the wrist and innervates the finger flexors. Symptoms include numbness, tingling, an aching sensation and wrist pain (most often at night). 

• Tendinitis – involves sore and inflamed tendons with symptoms including pain, swelling, tenderness, and weakness in the areas of the hand, elbow, and shoulder. 

• Rotator cuff injury – occurs when one or more of the tendons attached to one or more of the four rotator cuff muscles in the shoulder are inflamed. The symptoms include pain and limited range of motion in the shoulder. 

• Tenosynovitis – involves the swelling of one or more tendons (which attach a muscle to a bone) and the sheath that covers the tendon(s). Symptoms include swelling, tenderness and pain in the hand and/or arm. 

• Epicondylitis (“tennis elbow”) – caused by inflammation of the tendons within the elbow. The symptoms involve pain, swelling and weakness.

• Raynaud’s syndrome – occurs when blood vessels in the hand constrict from cold temperature, vibrations and possibly emotions. Both hands simultaneously become cold, blue, and numb, causing a patient to lose fine motor control and the manipulative ability of the hands. Upon recovery, the hands become red, accompanied by a burning sensation. 

• De Quervain’s disease – involves the tendon sheath of both the long and short adductor muscles of the thumb, which often become narrower due to repeated deviations of the wrist. It is particularly common in women who perform repetitive manual tasks involving inward hand motions and firm gripping.

Think of Your Body as a ‘Traffic Light’ with Green, Yellow and Red Pain Signals

For industrial athletes and sports enthusiasts dealing with repetitive motion injuries, Summit Daily recommends that you think of your body as a traffic light with green, yellow, and red signals. On “green light” days when you feel good, continue physical activities which are stressful to your body and be sure to take a rest period afterward. 

On “yellow light” days when you feel moderately sore or tender, proceed with caution regarding the physical activities that aggravate recurring pain. On days when you feel your body is in the “red” danger zone, curtail all physically stressful activities, particularly those activities that are both physically and psychologically stressful.

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Pay Attention to Pain and Take Regular Breaks

Be sure to pay prompt attention to the first sparks of pain. Keep in mind that some simple precautions can prevent disability later.

Many employers recommend that employees who spend considerable hours in front of a computer workstation should follow the 20-20-20 rule. This rule means that every 20 minutes, employees should stop their work and look at something 20 feet away for 20 seconds.

In addition, simple software with on-screen instructions can be added to your computer to remind you when you are due for a break. In addition, remember to give your hands a break whenever possible via electric staples, electric can openers and other machines to save yourself from repetitive motion injury.

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How to Avoid Repetitive Motion Injuries

Here are some do’s and don’ts for avoiding repetitive motion injuries at the computer:

• Adjust your computer’s display screen so it’s about two feet away and just below your line of sight. Also, adjust your lighting appropriately to avoid excessive eye strain.

• Keep your wrists straight and forearms parallel to the ground at the keyboard. Your elbows should bend at 90-degree angles (i.e., don’t reach forward) and make sure that your computer chair has adjustable forearm rests that attach to the chair to keep your wrists in place.

• Be careful not to lean on your elbows or perform any other activity that can compress and irritate your nerves. Wrist supports that lie on the desk work fine for most folks, but avoid strapping on wrist splints while typing. Using wrist splints in this manner can cause atrophy in some important muscles and create a potential muscle imbalance.

• Keep your hands warm to maintain good blood circulation. Avoid smoke-filled environments; smoking cigarettes has been shown to reduce peripheral blood flow and promotes repetitive stress disorders. 

• Take regular breaks from typing on the computer by rotating to other tasks, such as writing. Fat, round writing implements can provide relief and are often easier on the hands and wrists. Also, keep in mind that several brief breaks during the day are better than a single long one.

• Stretch out your forearms by resting one forearm on a table, grasp the fingertips of that hand and gently pulling back the fingers. Hold that position for five seconds and repeat it with the other hand. Another exercise includes pressing your palms flat on the table as if you’re doing a pushup and leaning forward to stretch the forearm muscles and wrists. Clenching your fist and then extending your fingers repeatedly may also bring some relief.

• Stand up and shrug your shoulders while keeping your arms at your sides. Your shoulders should first go upward, then squeeze them backward, downward and forward while you count to seven. Circular neck exercises and side-to-side neck flexion will also help relieve muscle stress and promote relaxation.

• Adjust your chair height so you are relaxed. Your weight should be evenly distributed, with your knees bent at a 90-degree angle and your feet flat on the floor.

Treating Repetitive Motion Injuries

There are various methods of treating repetitive motion injuries. Cryotherapy (the application of cold) is often an effective treatment for overuse-related musculoskeletal injuries, such as tendinitis and shoulder and back pain. Cold deadens pain and reduces muscular spasm by blocking nerve conduction velocity and muscle spindle excitability.

When cold is applied, vasoconstriction (narrowing) of blood vessels occurs and an increase in blood viscosity (thickness) ensues, which reduces inflammation and slows down swelling (edema). Increasing external pressure using an elastic compression wrap greatly assists cryotherapy’s effectiveness.

Cryokinetics is a highly successful rehabilitation technique that combines the application of cold with stretching, massage, and mild exercise in the days/weeks following extreme soreness or injury. The affected joint or muscle is first numbed by cold. Then, it is put through various ranges of movement and controlled exercise until pain is felt and the cold is then reapplied. Repeating this cycle several times has been shown to accelerate healing, as does contrast treatments (alternating cold and heat therapy) in some athletes.

Proper back mechanics should certainly be emphasized in any discussion involving office environments and repetitive motion injuries, especially to the upper extremities. Chronic back problems due to prolonged sitting can often be alleviated through simple postural habits such as sitting straight.

Developing the muscular strength to sit up straight for hours while you’re hunched in front of a computer desk is rarely achieved by most people. Over time, the back muscles and ligaments become fatigued and overstretched, creating a painful slouch or slump (forward flexion) in the lumbar spine.

Extended sitting in a conventional chair that forces a 90-degree angle between the thigh and torso is considered the best posture for chair sitting. Unfortunately, this type of chain allows the pelvis to rotate backwards, resulting in a flattening of the normal lumbar curve normally seen during standing.

Research has determined that maintaining the natural lumbar curve found during standing is clearly the best posture for sitting. The loss of a normal lumbar curve is associated with overstretching the back’s tiny paraspinal muscles and their ligaments.

Daily Stretching Exercises Can Also Alleviate Repetitive Motion Injuries

When performed daily, these stretching exercises can help strengthen and improve flexibility of wrist and hand muscles, thus helping to relieve strain caused by tasks that require repetitive motions.

• Thumb stretch – Gently pull your thumb backward and hold that position for five to 10 seconds as a moderate stretch is felt. Repeat the exercise three times with each thumb.

• Hand stretch – Make a fist and then extend fingers apart as far as possible, holding for 10 seconds. Relax and repeat up to 10 times until hands and fingers feel relaxed.

• Hand grip – Squeeze a hand grip device 30 consecutive times, pacing yourself to be able to complete the 30 repetitions. This exercise will develop your finger, hand and forearm muscles. Some fancy hand grippers are now available in many stores (marketed as stress reducers); they are simply rugged balloons filled with fine-grade sand. An old tennis ball or racquetball can also be used to provide exercise.

• Thumb squeeze – Hold the hand grip device in the palm of your hand and press it with your thumb without using your other fingers. Repeat 25 times with each thumb.

• Finger squeeze – With the hand grip device in the palm of your hand, squeeze it by exerting pressure with your four fingers toward your thumb. Use a rolling action as if you are making a fist and repeat the exercise 25 times with each hand.