Repetitive Stress Injuries: What are they and how do they occur?
Repetitive stress injuries, or overuse injuries can occur with any type of activity, or inactivity. They typically occur in the joints, large or small, and can occur from small body movements such as typing, large movements such as kicking, or from holding bodily positions for long periods of time such as sitting. They also do not discriminate; they can occur in athletes, people who exercise moderately, those who are inactive but of normal weight, people who are overweight, and people who are underweight. Nearly all of the injuries discussed below can occur with trauma, e.g. a fall, but that is not what is being presented here. The types of injuries discussed are the ones that occur over time, so you do not know it is happening at the time. The injury does not present itself until months or sometimes years later, after the damage is done.
Types of Injuries
Bursitis is the inflammation of the bursa, small fluid-filled sacs that cushion and lubricate a joint. Tendinitis is the inflammation or small tears in the tendons. Tendons are at the end of a muscle and attach to the bone. Strains are tears of the muscles, sometimes called pulled muscles, and are caused by over stretching or a muscle imbalance. This obviously, can occur in almost every skeletal muscle in the body. A sprain occurs in the joint and is more serious than a strain. The technical definition of a sprain is when the ligaments or tendons that secure a joint are stretched or torn. Because of their limited blood supply, tendons and ligaments heal very slowly. Serious ligament sprains often have to be surgically repaired as soon as possible, as the ligament can soften. Some surgical procedures include replacing the ligament with an artificial one or one donated by a cadaver. generative joint disease is caused when cartilage, the connective tissue located at the end of bones to protect and cushion the joints during movement, wears away or tears. Spinal injuries most commonly occur as degenerative disc disease, or a herniated or bulging disc, usually in the cervical or lumbar spine. Discs are gel-like cushions between vertebrae holding them in place, and avoid the painful “rubbing” of the two bones. Sometimes the herniated disc can touch a nerve, leading to extreme pain. In the lumbar spine, it can push on the sciatic nerve, leading to sciatica (Clark, et al. 2004). Wrist injuries, such as carpal tunnel syndrome (CTS) tend to develop slowly, unlike many other injuries in the knee or back. Compression of the median nerve is the principal cause of wrist injuries can express themselves as a dull ache, and eventually sharper pain, as well as numbness and tingling in the hands, wrists, and/or forearms. An article written by Carol Krucoff (2003) sites scientist Roger Cole, Ph.D., who stated that the “lower back (lumbar spine), knee, and neck (cervical spine) are the most prone to injury, followed by the sacroiliac (SI) joint, and the origin or attachment of the hamstring muscle where it joins the sitting bone Krucoff (2003).
Bursitis
This type of injury can occur in the shoulder, elbow, and knee. Repetitive movements at the joint or performing movements or exercises out of alignment (poor form) can cause inflammation of the bursa. The shoulder joint is a common point of injury due to its instability. Examples at the shoulder or elbow are a carpenter constantly using a hammer, playing tennis, performing overhead presses (shoulder presses), or chest presses with too much weight, in poor form, or less weight and very high repetitions. Examples at the knees are, locking your knees when standing for long periods, climbing stairs, playing soccer, running or jogging, performing squat or lunge exercises in poor form, with too much weight, and too little weight with high repetitions.
Tendinitis
Some of the joints where this can occur are the shoulder, elbow, spine, hip, and knee. Examples of movements at the shoulder or elbow are the same as above in bursitis, in addition to lateral movements (side raises) at the shoulder with too much weight or poor form. Impingement syndrome (weightlifter’s shoulder) is when tendons become trapped under the acromion. The tendons become compressed, damaged, and inflamed leading to rotator cuff tendonitis. Tendinitis in the knee can also occur from the same movements, exercises above for bursitis. A common form of tendinitis is lateral epicondylitis (tennis elbow). This pain occurs primarily where the tendons of your forearm muscles attach to the bony prominence on the outside of your elbow. Pain can also spread into your forearm and wrist. Although common in tennis players, common activities that involve repetitive bending of the elbow can cause this injury (retrieved October 29, 2009 from www.mayoclinic.com/health). Remember, these overuse injuries do not occur your first day on the job, or your second tennis match, or your third time performing squats. They occur over time by repetitive movements.
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Strains
Strains can occur more commonly in the muscles of the rotator cuff, four muscles that help the shoulder form a socket around the head of the humerus bone, and in the hamstring where attaches at the sitting bone (ischial tuberosities), pectoral muscles, or muscles around the scapula. Muscles imbalances caused by sitting or maintaining any one position for long periods of time, over training one muscle group while not training the opposing muscle group, poor posture, can all lead to one muscle group being tight, while the opposite muscle groups being over stretched. When the over stretched muscles are recruited for an activity or movement, they might not be strong enough, and result in tiny tears that worsen over time. For example sitting all day at a computer with your shoulders rolled forwards can tighten the pectoral and anterior deltoid muscles, while overstretching the posterior deltoids and rhomboids. Then when you go to pull an object towards you, whether it is an exercise or lifting something off the floor, the weak muscles can tear.
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This is more common among the rotator cuff tendons that attaches at the shoulder, and the tendon that attaches the hamstring to the sit bone, ankle, knee and wrist. It usually occurs with more weight bearing exercises such as running, weight lifting, or explosive movements that occur while playing sports such as tennis or soccer. These again can occur from a trauma injury such as a fall or impact, but can also occur over time through repetitive movements that slowly stretch a tendon or ligament.
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Pelvic alignment has a tremendous effect on lower spinal alignment. Tilting your pelvis forward can cause excessive lordosis in the lower back; tightening the muscles, pushing the discs inward, and causing pain and discomfort. Tilting it backward can cause the lumbar spine to straighten, pushing the discs outward, leading to disc herniations. Lower back and SI injuries are often linked to forward bends,” Cole states, “because they can place strain on the disks and ligaments at the base of the spine.” Forward bending to lift objects places a tremendous amount of stress on the lumbar spine, forcing the discs outward. Also loading the spine with weight, then performing squatting and lunging exercises with the pelvis out of alignment can lead to disc herniations. Sitting for long periods of time, especially with the pelvis slightly tilted back can stress the lumbar spine, and push the discs outward. Performing sit-ups or crunches essentially flex the spine (straightening it) and pushing the discs outward. Therefore, performing weight bearing crunches or performing dozens to hundreds at a time can lead to not only muscle imbalances, but also disc herniations (Krucoff, 2003).
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Wrist is a common joint for sprains, strains, as well as Carpel Tunel Syndrome. The wrist is a small, flexible and delicate joint. Small repetitive movements such as typing can lead to CPS. However, sprains, strains are likely due to weight bearing exercises such as pushups or bench press with too much weight, or some yoga poses wrists out of alignment. Ideally, the wrists should be properly aligned with the elbows and shoulders during exercise. Weight training should be done gradually, and with stability straining, to strengthen and improve stabilization of the wrist.
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So how does difference in body weight or mass effect these overuse injuries? First, those who are considered underweight often lack muscle mass, so when they perform an activity or exercise, the impact places more stress on the joints, instead of the muscle bearing the weight. Someone who is in the normal weight range, but also lacks muscle tone, will have the same issue as someone who is underweight, but more so. People who are in the normal weight range, but do not perform weight-bearing exercises, often will carry a high percentage of their body weight as fat (up to 30%). Therefore, although they look average in their clothes, in their bathing suit, they lack muscle tone. This additional body weight with the lack of muscle to relieve the joints can result in these types of overuse injuries when performing activity over longer periods. Those who are overweight or obese exacerbate this same concept.
Obesity
According to Carlton G. Savory, MD, joint forces are approximately one and a half times one’s body weight when walking on level ground. This means that when a person weighing 200 pounds is walking along a level sidewalk, the forces on the joint are the same as for a 300-pound person standing still. Other activities place even greater forces on the joints. Standing up out of a chair or going up and down stairs increases the force to approximately 2 to 3 times body weight. For those who are overweight, this means dramatically increased force on the joints. That excess weight that is being carried around acts as a catalyst to degenerative disease in the joints (Savory, www.hughston.com).
Therefore, every movement, whether seated or standing that an obese person makes, stresses the joint. The spine is designed to carry the entire weight of the upper body. When all that excess weight by someone who is obese is carried, the spine is forced to absorb the burden; in which the consequence is that the spine can prematurely wear out. Consistent, excessive pressure on a disc can cause some of the jellylike material in the center of the disc to squeeze through the tears in the capsule, causing the disc to rupture (herniate) into the space that surrounds a nerve root or the spinal canal. A herniated disc can interfere with nerve function, leading to weakness, numbness, or pain in a leg or arm, or sciatica (retrieved October 12, 2009 from http://www.hughston.com/hha/a_16_2_1.htm).
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Ways to reduce your risk of repetitive stress/overuse injuries
2. Mix it up
Perform different cardiovascular activities and vary your weight training exercises. Unless you are a professional athlete, there is no need to continue doing same thing week after week. You are putting yourself at risk for an overuse injury.
3. Know your limits.
Depending on your goals, you should determine your repetition range for your exercise. Typically, for weight training, you do not want the reps to exceed 15-20. If you do more than this, the weight is not intense enough and the muscles are not being worked. Unless you are a competitive weight lifter or a professional athlete, you do not want your rep range to go below 8-10 for muscle growth. Often the muscles become stronger faster than the tendons and ligaments, putting them at risk of stretching or tearing.
This rule is the same for cardio. If you can go beyond 20-30 minutes, you are not getting an intense enough workout and placing too much stress on the joints. Unless you are training for a marathon or a 150-mile bike race, you have no business doing that much cardio. You are putting yourself at risk for an overuse injury.
4. Warm-up and cool down
Never jump into and intense workout with the muscles and joints “cold.” Spent at least 5-10 minutes performing a general or specific warm-up to increase the body temperature, activate muscles, and lubricate the joints. Always cool down the body after your workout with appropriate stretching.
5. Wear proper footwear
Make sure your shoes are appropriate for the activity, fit properly, have plenty of arch and heal support, and replace them when they become worn-out.
6. Partner up
There is no substitute for a trained and attentive personal trainer, in addition to being attentive to one’s own body. However, if you are not working out without a trainer; try to find a partner who can watch your form and make corrections as you work out; preferably, someone who also understands proper alignment and form.
7. Remember R.I.C.E. if it hurts
Stop performing the exercise, in other words, Rest. Ice the area for the first 48-72 hours, no longer than 20 minutes at a time. Wait at least another 20 minutes before icing again. Compress the area and Elevate above the heart if possible. If it is not better in a few days, call your doctor. Do not ignore pain, numbness or tingling, even if it comes and goes, these could be early signs of an overuse injury.
8. Take a break
At least every few months, take a week off from either all exercise, or just resistance training and perform moderate cardio. This allows the muscles and joints to rest, repair, and prepare the body for future activity. When you are sick or on vacation is a great opportunity to put your body on vacation.
References
Clark, M., Lucette, S., Corn, R., Cappuccio, R., Humphrey, R., Kraus, S.,Tichenal, A. & Robbins, P. (2004). Optimum Performance Training for the Health and Fitness Professional. National Academy of Sports Medicine, Calabasas, CA.Hirsch, L. (2006). Retrieved October 28, 2009 from http://kidshealth.org
Krucoff, C. (2003). Insight from Injury: If the practice of hatha yoga was meant to heal, why so.many yogis getting hurt? Retrieved.October 12, 2009 from www.yogajournal.com.
Savory, C. Retrieved October 12, 2009 from www.hughston.com/hha/a_16_2_1.htm
www.mayoclinic.com/health, retrieved October 28, 2009.
Images:
A retrieved October 12, 2009 from allaboutarthritis.com
B retrieved October 12, 2009 from menshealth.com
C, D, E retrieved October 12, 2009 from http://health.allrefer.com/health
F retrieved October 12, 2009 from www.webmd.com/pain-management
G, H retrieved October 12, 2009 from www.eorthopod.com/public/patient_education
I retrieved October 12, 2009 from www.webmd.com/pain- management
J, K L, M, N retrieved October 12, 2009 from http://health.allrefer.com/health
O retrieved October 12, 2009 from www.hughston.com/hha/a_16_2_1.htm
Melanie Clark Mogavero, CSCS, CPT, RYT
