If you think that football is the sport with the most injuries, you would be wrong. Each year, 79 percent of long-distance runners suffer injuries that force them to take time off from running (Br J Sports Med, Aug, 2007;41(8):469-80). The most-injured part is the knee and the chance for an injury increases with running longer distances and having previous injuries. Injuries occur most often after a rapid increase in weekly distance, intensity, or frequency of hill or track workouts.
You can help to prevent wear-and-tear injuries from any type of exercise by warming up, by stopping exercise when you feel pain and by not exercising intensely when your muscles feel heavy or sore. Muscles are made of millions of individual fibers. When you first contract a muscle, you use only one percent of the fibers. As you continue to exercise, you contract more fibers to share the load, which places less force on each fiber and helps to prevent injuries.
Always warm up, and go slow before you go fast. If you take a hard workout and feel sore the next day, go easy until your muscles no longer feel sore after you have warmed up. It usually takes at least 48 hours for muscles to recover from hard exercise. When you feel pain in one muscle during exercise, that’s a signal that it may be starting to tear and you should stop exercising for that day.
Why Running Causes So Many Injuries
When you run, one foot is always off the ground, so each foot strikes the ground with a force equal to three times body weight (at 6-minute-mile pace) and the faster you run, the greater the force of each foot strike. Walking is much safer. When you walk, you always have one foot on the ground, so the force of a walking foot strike almost never exceeds your body weight.
A study from the University of Wisconsin-La Crosse showed that as people start to feel tired during running, they shorten their strides and this decreases the force of their foot striking the ground (Medicine and Science in Sports and Exercise, Dec 1999;31(12):1828-33). The shorter stride lessens the force of their heel striking the ground and places it forward to the area behind the big toe. To compensate for the decreased force of their feet hitting the ground, they move their legs at a faster cadence. You can use this information to help you prevent injuries when you run. Shortening your stride will help to protect you from injuries by shifting your foot strike force forward. You can keep your speed by moving your legs at a faster cadence. See Prevent Running Injuries with Shorter Strides and Orthotics
Understanding How to Train Helps to Prevent Injuries
The most common cause of injuries is not listening to your body when it talks to you. Every wear-and-tear injury you have had probably gave you signals long before you were injured. Most exercisers who are training properly have sore muscles every day when they wake up in the morning. However as they start to exercise, the soreness goes away and their muscles feel good. On days when your muscles do not feel better after you warm up, take the day off. Pain in one area, such as a leg, and no discomfort in the other leg, is a strong warning of impending injury that could still be prevented.
To strengthen your heart and increase your ability to take in and use oxygen, you have to exercise intensely enough to feel muscle burning and become somewhat short of breath. That stresses your muscles also. To make a muscle stronger, you need to exercise vigorously enough to damage it. You go a little faster on one day, damage the muscles and feel sore on the next day. This delayed-onset muscle soreness (DOMS) is evidence that you have damaged muscles. The soreness is a sign that you should spend that day exercising at a more relaxed pace and not put much pressure on your healing muscles.
In a stress/recover training program, you should set up your schedule to go a little faster with more intensity on one day, feel sore on the next day and go at low intensity for that day and as many additional days as it takes for the soreness to go away. Then, when the soreness is gone, you exercise more intensely again.
• Do not do the same exercise at the same intensity every day. Use the hard/easy principle: faster on one day and much slower on the next.
• Always go much slower for several minutes before you go faster.
• If your muscles do not feel fresh after you have warmed up for a few minutes, take the day off.
• Stop exercising immediately if you feel pain in one area that worsens with exercise.
• Whatever your sport, understanding the principles of training helps to prevent injuries.
Caution: Almost everyone should exercise. Check with your doctor before you start a new exercise program or increase the intensity of your existing program. Blocked arteries leading to your heart can cause a heart attack during exercise.
Gabe Mirkin, M.D., is a sports medicine doctor and fitness guru. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin has run more than 40 marathons and is now a serious tandem bike rider with his wife, Diana. His website is http://drmirkin.com/. Click to read Gabe’s full bio.