Health&Nutrition
INJURIES: Stress Fractures
August 4, 2009By Melissa Helquist
An average runner will pound the pavement 5,000 times per hour, per foot. This makes runners prime candidates for stress fractures, which are tiny bone fissures caused by overuse and repetitive impact. Stress fractures are most common in the metatarsals and tibia of the lower legs and feet, but can also strike the hips, sacrum, femur and elsewhere.
Stress fractures occur when muscle groups are overworked and can no longer absorb shock, which is then transferred to the bones. Because of the high-impact, repetitive nature of running, runners tend to be more at risk for stress fractures than other athletes. According to researchers at Massachusetts General Hospital, 69 per cent of all cases of stress fractures were attributed to runners, and the injury accounts for about five per cent of all running-related injuries.
Are You At Risk?
Trainer and former professional triathlete Ian Fraser says stress fractures are the last link in a chain that includes muscle fatigue, biomechanical imbalances and poor diet.
Increasing mileage too quickly can make the muscles overtired, leading a stress fracture. Runners starting a new training program or resuming a running routine after a long absence need to be careful about how they increase mileage in order to avoid stress fractures.
While overtraining is the primary cause of stress fractures, the risk of injury is complicated by biomechanical alignment. Runners often have overdeveloped lateral muscles, an imbalance that can cause unnecessary strain on other muscle groups. Individual imbalances in gait and body alignment can increase a runner’s chance of a stress fracture.
Continuous running on hard surfaces such as pavement and concrete increases the impact on bones and muscles and wear on shoes, forcing the body to absorb more of the shock. Also, Stephen Handel, a certified athletic trainer with Ottawa’s Algonquin Sports Therapy Clinic, says that if a runner takes the same route every day, repetitive surface angles can cause an imbalance in muscle use, leading to fatigue in one muscle group that may lead to stress fractures.
Beyond training habits, other risk factors are diet and gender. Even without overuse, runners with a calcium deficiency can be at greater risk because the bones are already weaker and more susceptible to injury. The calcium factor means that women tend to be more at risk for stress fractures than men, especially women who have infrequent or absent menstruation.
Keys to Prevention
According to Fraser, the key to preventing stress fractures is “sensible training, both body work and body care.” Just as risk extends from a variety of factors, so does prevention.
1) Build mileage slowly. Weekly mileage increases shouldn’t exceed 10 per cent. This isn’t an absolute rule, and will depend on base fitness and experience. Runners should also pay attention to their bodies and respond to soreness. Handel recommends keeping a training log to ensure that mileage increases aren’t too drastic and to provide a record that can help in diagnosis and treatment if an injury flares up.
2) Improve flexibility and strength. Regular strength training can provide balance and symmetry to muscle groups, allowing more stability for joints and bones. Fraser recommends regular massage, stretching, yoga and strengthening, emphasizing the strength training. For general strengthening in areas prone to stress fracture, Handel recommends focussing on the IT band, glutes and hip flexors. To strengthen the foot, Handel recommends toe crunches: with the toes, scrunch up and lift a towel or lift marbles. While general strengthening can be beneficial, getting a muscle balance assessment from an athletic therapist or trainer can help you to pinpoint problem areas and establish a strengthening program unique to your body and habits.
3) Wear good shoes. Running shoes absorb shock, so get ones that fit and keep them in good condition. Good tread is also important, according to Handel, especially in our Canadian winters. She also recommends wearing supportive shoes even when not running. Varying your route and running surfaces minimizes shoe wear.
4) Eat a balanced diet. To support the bones, get the recommended amount of calcium in your diet, especially if you have a known deficiency.
5) Respond to pain. Because the stress fracture is a progressive injury, it’s crucial to respond to pain early. “Athletes are in tune with their bodies,” Handel says, “so prevention is about paying attention to small changes in the body and responding.”
Steps to Recovery
A stress fracture is a gradual onset injury, so paying attention to small changes in the body can prevent more serious injury. It may start as soreness at the end of a long run, progressing to discomfort throughout a run and finally, pain, even at rest. Stress fractures can also cause swelling and pinpoint pain at the injury site. If pain persists during workouts, or extends beyond physical activity, consult a physician or athletic therapist for diagnosis and treatment. Diagnosis for stress fractures is made through symptoms, history and often an X-ray or bone scan. Typically, rest allows the fissures to heal fully, but in some cases, casting is required. For any stress fracture, rest is essential, because the small fractures can lead to secondary complications or chronic injury. During the resting period, low-impact cross-training activities such as cycling, swimming and water running can typically be done safely. While stress fractures are treatable, full recovery can take six to eight weeks of rest from running, so prevention is always the best approach.
Melissa Helquist is a freelance writer based in Ottawa.
Stretches and Strength Exercises to Work Stress-Fracture Hotspots
1) ITB Stretch: Lying on the back, extend both legs out straight on the floor with arms out to the sides for support. To stretch the right leg, bend the right knee, bring the thigh up to 90 degrees from the torso and allow the leg to fall to the left over the left leg. Bring the left ankle on top of the right knee and use the left leg to push the right knee towards the floor. Keep hips square on the floor. You can vary the location of the stretch along the ITB by bringing the right knee either higher or lower. Repeat on the left leg.
2) Glute Stretch: Lying in a prone position with arms stretched overhead, bring the right knee (to stretch the right glute) up under the chest and position the right foot so that it extends just beyond the left side of the torso. Allow body weight to fall onto the right knee, thereby assisting the stretch of the right glute. Repeat on the left leg.
3) Hip Flexor Stretch: Go into a lunge position with one knee on the ground and the opposite side’s foot on the ground. Push hips forward until a stretch is felt in the front of the hip.
4) Calf Stretch: Stand facing a wall about one large step away from it. Position feet, one ahead and one behind you. Keep the heel of the foot behind you on the ground and place hands on the wall. Lean into the wall until you feel a stretch in the back of the lower leg.
Hold all stretches 2-3 x 30 seconds. They should feel comfortable, not painful.
One-legged squats to work the glutes: Stand on one leg with the other leg held straight out in front, the heel near the ground. Using the arms as a counterbalance out in front and keeping the lower back straight and abs strong, slowly lower yourself down on the working leg until at or near 90 degrees. Make sure the knee doesn’t go past the toes. Hold at the bottom for 2 seconds, then raise back up until the leg is nearly straight. Do 2-3 sets of 10 reps on each leg. You can make this exercise easier by doing it against a wall.
