Constant running causes overuse injuries

Story and photo by Capt. Vancil McNulty U.S. Army Center for Health Promotion and Preventive Medicine

Everyone has different motivations to exercise. But if you’re are a Soldier, your
exercise motivation may simply be to pass a Physical Training test.
One of the pitfalls of preparing Soldiers to meet the physical rigors of completing the mission may be overtraining, or overuse. Overtraining occurs when the amount of exercise is out of balance with recovery or rest. When this happens, it can cause injury.

The Joint Services Physical Training Injury Prevention Work Group thoroughly reviewed proven injury-prevention strategies in the military. The group found that too much running was the primary contributor to overuse, and those at the greatest risk of injury are those who are least fit.

A large amount of military and civilian research shows that the amount of running significantly increases the risk of leg injuries. During initial military training, about 25 percent of men and about 50 percent of women incur one or more PT-related injuries. About 80 percent of these injuries are in the legs and are caused by excessive running.The group found that decreasing the amount of running helped reduce injury.

Marine recruits in a 12-week boot camp had a 54 percent reduction in stress fractures of the legs with essentially no change in aerobic fitness when they reduced their running mileage 40 percent.

Another study compared male Navy recruits assigned to basic training divisions who ran either 12 to 18 miles or 26 to 44 miles. The lower-mileage division had lower injury rates, with 1.5-mile run time improvements that were the same as the higher-mileage divisions.

A reduction of 20 miles of running during this Navy recruit training reduced injuries by 20 percent without negatively affecting physical fitness.
There are thresholds of running above which injuries increase dramatically without any significant gains in fitness. Running frequency of five times a week versus three times a week for 30 minutes increases the incidence of injury by 225 percent without significantly improving fitness level.

Running durations of 45 minutes versus 30 minutes three times a week increases the incidence of injury by 125 percent without any significant change in fitness.
The bottom line: If Army leaders are serious about taking care of Soldiers and reducing PT-related injuries, there is plenty of hard evidence that proves less is more.