The Cooper Institute

Founded in 1970 by the "Father of Aerobics"
Kenneth H. Cooper MD, MPH


Most Important Risk Factors for Exercise-Related Injuries

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Move more

Monday, Jun 06, 2011


Finding ways to engage in physical activity while avoiding injury is a major goal of training programs. All activities have risks. Most of the time the benefits outweigh the risks, as was discussed last week in the post “Exercise: Why Risk the Injury.” As discussed, “active individuals had a 17%-19% lower chance of injury during non-sport or non-leisure time activities than those who were inactive”. But injuries still exist in activity.1

Research on exercise-related injuries was sparse at the peak of the fitness boom in the 1980s. Since then, studies have attempted to understand injuries. But this area is still limited, especially in females. Most of the data comes from runners in the civilian sector and military studies. Most documented injuries occur to the lower extremities.2 This has been reported from research on runners and in the military. In the military, 80-90% of injuries were seen in the lower body. In runners, approximately 25%-65% of runners report being injured to the point they reduce or stop training annually.2

So when do the risks of injury increase?
Effective exercise programs are built on the concept that exercise sessions must challenge the body versus continuing to do exactly the same thing. But how this is done and how the program is designed is a major factor in injury incidence. Studies from the military indicate that 60-80% of injuries are related to overuse.2 Overuse injuries often include things such as achilles tendinitis, patellar-femoral syndrome, plantar fasciitis, and stress fractures.

The same training factors that are needed to create a training effect and challenge the body in exercise sessions are some of the common factors related to injury. These factors include frequency, duration, recovery, and intensity to name a few.2,3,4 But these are not the only ones; research specific to knee injuries has also linked factors such as the environment, knee bracing, shoe surface, and even weather.4

Research concludes that there are preventive steps to prevent injuries. This has been specifically shown with knee injuries. Ratzlaff and Liang found that most knee injuries are not the result of contact or collision but neuromuscular and biomechanical issues. These neuromuscular and biomechanical issues include collapse of the knee, reduced knee flexion, decreased core and trunk control, increased hip flexion, improper landing flatfooted, and less plantar flexion.4

To prevent injuries
But many injuries can be prevented by following a few simple recommendations.2,3 Most of these recommendations surround the important factors related to common exercise-related injuries /  overuse. To help prevent overuse injuries:

  • Individuals with a low fitness level should start at lower levels of exercise – even as little as 5 to 10 minutes, and then progress slowly
  • Exercise frequency, duration, and intensity should be individualized to an individual’s fitness level
  • Increases in frequency, duration, and intensity should progress slowly and be tracked
  • Sufficient recovery between workouts should be allowed
  • Individuals should be aware of early warning signs of potential injury, such as increasing muscle soreness, bone and joint pain, excessive fatigue, and performance decrements, and then reduce exercise until symptoms diminish

Additional recommendations to help prevent injuries in the knee specifically, include considering: soft surfaces for running and jumping exercises, proper footwear, and some injury prevention training. Injury prevention training has displayed strong evidence for reducing ACL injuries when plyometrics, balance, and strengthening are incorporated.4

Evidence suggests that injuries can be averted and that most exercise has a protective effect against injury as was discussed last week.1,5 But, exercise should be done with consideration of the above recommendations to prevent injury, with special attention on preventing overuse.

1Howard, E. (2011, May 30). Exercise: why risk the injury?

2CDC. Exercise-Related Injuries Among Women: Strategies for Prevention from Civilian and Military Studies. MMWR. March 2000;49(RR02): 13-33.

3Vetter, R.E., Symonds, M.L. Correlations Between Injury, Training Intensity, and Physical and Mental Exhaustion Among College Athletes. J Strength and Conditioning Res. March 2010; 24(3): 587-596.

4Ratzlaff, C.R., Liang, M.H. New Developments in Osteoarthritis. Prevention of injury-related knee osteoarthritis: opportunities for the primary and secondary prevention of knee osteoarthritis. Arthritis Res Ther; 2010; 12(4): 215.

5Urquhart, D.M., Tobing, J.F., Hanna, F.S., Berry, P., Wluka, A.E., Et.Al. What is the Effect of Physical Activity on the Knee Joint? A Systematic Review. J of Epidemiology. March 2011; 43(3): 432-442.