Exercise Injury Prevention

Running in the Fast Lane | Listening to your Body | Training Errors Training Principles | Practical Training | Psychological Factors

Practical Characteristics Associated with Training

While these positive training principles yield suggestions to limit injury risk, they are implemented in a program over time. Day-to-day exercise issues include the role of warm-up, stretching, and a cool-down. They prepare the body psychologically and physically for your workout. Additionally, it is widely believed that properly performed, these measures help limit the risk of injury.

Warm-up: The warm-up session is preliminary exercise, which may last a half-hour or more in competitive sports. For recreation, the warm-up is normally much shorter and may practically consist of simply jogging the first mile slower than normal training pace. The purpose of the warm-up is to elevate the heart rate and increase the body temperature by several degrees. It helps a person to psychologically prepare for the exercise session. Since movement is occurring with the warm-up activity, the range of motion of the joints and the efficiency of muscle contractions are also enhanced.

The increase in muscle temperature associated with an adequate warm-up can result in increased performance. Donald Kron of the Sports Medicine Clinic in Lake Charles, Louisiana, reports that warming-up the legs results in an increased vertical jump and an increase in maximum cycling power. "We have an easier time selling athletes on stretching to enhance performance than to prevent injuries," says Kron. "We like to design stretching programs that allow the athlete to rehearse the movements required in each sport." The warm-up often consists of both general exercises, such as calisthenics, stationary bike cycling, or jogging, and exercises that are specifically related to the chosen activity. Examples of a specific warm-up are swinging a golf club or tennis practice, which are skill rehearsal for the activity.

Stretching: Stretching is routinely included in the warm-up outlined above, because it seems reasonable and makes sense. However, the jury is out regarding its efficacy, particularly if engaged in prior to an activity like jogging. Dr. Van Mechelen found that injured runners have stretched significantly more before running than non-injured runners, and FitNews, the publication of the American Running and Fitness Association, has referred to stretching for injury prevention as the "Myth of the Month." FitNews summarizes the debate by noting that, "No matter how hard you look, you won't find a single controlled research study that proves stretching reduces the frequency of injuries." Additionally, there does not appear to be any hard evidence that supports the contention that stretching will decrease post-exercise soreness, although continuing research is underway. However, the stretching procedure intuitively seems to be an appropriate part of the warm-up routine and may be a form of an insurance policy for some. As the Penn State Sports Medicine Newsletter suggests, "No one wants to be blamed for an injury because he or she did not use all of the warm-up tools available."

This controversy does not mean that stretching is useless. Stretching will increase your flexibility if performed properly over time. The research cited above, however, questions why stretching needs to be done routinely, and if so, how should it be done? The answer to the first question appears to be a qualified 'yes,' stretching should be done routinely. The effectiveness of stretching to achieve flexibility makes it an important tool for the maintenance of joint range of motion that naturally tends to decrease over time.

Stretching for flexibility will help minimize the loss of elasticity and counteract some of the connective tissue stiffness that occurs with time. This type of stretching is part of a program that should be sustained over a period of months for sustained increases in joint motion. As investigators at The University of Illinois point out, there is no reason to expect significant flexibility decrements over time in healthy adults. Their research has found that differences in flexibility with age are so minimal as to be of limited clinical importance. At least to 74 years, any substantial loss of joint mobility should be viewed as abnormal and not attributable to aging, and therefore, should be treated much as it would be in a younger individual.

The second question dealing with how stretching should be done is a little easier to answer. That is, it is now clear that stretching cold muscles is a bad idea. Stretching should occur only after the temperature of the muscles has increased. It should be preceded by a warm-up or performed during and/or after workouts. Research by Dr. Dean Taylor and colleagues at Duke University suggests that the optimal time to hold a stretch is approximately 12 to 18 seconds. They note that the largest increase in flexibility occurs in the first four repetitions. In terms of how hard to push during the stretch, the guidance by Bob Anderson, author of Stretching (the best selling book on the subject) brings straightforward advice: "Good stretching is knowing your body. It has nothing to do with how far you can move any particular part. The feeling you get when you stretch is a good gauge. The right feeling is when you can perform a stretch, but it doesn't hurt."

Effective stretching starts slow, using a static or gentle isolated muscle stretch. Vigorous bouncing, sometimes called ballistic stretching, should be avoided at first because it loads the muscle-tendon unit too rapidly and increases the likelihood of a strain. Further, when a stretch occurs very rapidly, there is too little time for the normal connective tissue relaxation to occur, which may render the stretch ineffective.

Following an appropriate warm-up and gentle progressive stretching program, some ballistic activity may be appropriate as a prelude to a dynamic sports event. The key again is start slow and be warm and loose prior to engaging in explosive activities. Bob Anderson points out that, "There are many methods of stretching, some more complex than others, but if practiced regularly and with sensitivity, all seem to yield results." If soreness occurs, it suggests that overstretching is occurring and the vigor of the stretches should be decreased.

Joggers can start out slowly, and functionally loosen up as they progress through the first mile or so. Pre-exercise stretching may not be as important for them, but should be emphasized following the workout to promote flexibility. With golf, however, it's unlikely that you would want to drive with 50% effort on the first tee, especially with an audience surveying the shot. In this case, an adequate warm-up with some focused stretching exercises and activity specific repetitions should be performed before your game.

Cool-Down: The cool-down is designed to bring the body back to a pre-exercise level and minimize the effects of the workout on future flexibility. By protracting the exercise at a reduced intensity, the body can metabolize some of the soreness-producing lactic acid that has accumulated in the muscles during a vigorous workout. Additionally, if a person simply stops an workout, there is a chance that with the relaxation of veins in the legs, blood will pool there, and the person could faint. By maintaining activity at a reduced rate, cardiovascular function slowly returns to near the normal rest state. This is also an ideal time to stretch, since the muscles are warm and tissue compliance is greatest.

Source: Halle, J. (Ph.D., Lieutenant Colonel, US Army). Exercise Injury Prevention: Running in the Fast Lane. From "Executive Wellness: A Guide for Senior Leaders." U.S. Army Physical Fitness Research Institute (USAPFRI), U.S. Army War College (Eds.). Carlisle Barracks, Pennsylvania.

Running in the Fast Lane | Listening to your Body | Training Errors Training Principles | Practical Training | Psychological Factors