Nearly 30 percent of all injuries sustained by college athletes aren't caused by a single, traumatic event but rather occur gradually over time and result from repeated small injuries. That's according to findings recently published in the Journal of Athletic Training.
In the study (subscription required), Michigan State University researchers examined injury data from 573 male and female collegiate athletes participating in 16 team sports at the NCAA Division I level. Participants reported 1,317 injuries during a three-year period, and of those 386 were categorized as overuse injuries. Results also showed that a majority of overuse injuries, 62 percent, occurred in females athletes.
As someone who has rehabbed her fair share of such injuries over the years, the study caught my attention. Curious to know more on the topic, I turned to Michael Fredericson, MD, who has been head team physician with the Stanford Sports Medicine Program since 1992. Fredericson, whose primary area of research is overuse injuries among athletes, responds to my questions below.
Which athletes tend to be most affected by overuse injuries?
Overuse injuries are more often seen in athletes who participate in sports that involve repetitive movements, and such injuries are specific to the activity performed. For example, overhead activities, such as throwing in softball or spiking in volleyball, may contribute to joint-specific injuries in the rotator cuff muscles of the shoulder. Additionally, overuse injuries sustained during cross-country and track-and-field are more likely to involve stressors on the tendons, joints, and bones of the lower extremities and subsequent tendinitis of the knee and ankle or stress fracture of the long bones.
What factors may contribute to women's sports having a greater overuse injury rate?
Overuse injuries occur gradually as a result of chronic stress that affects the tendons, joints and bones of the musculoskeletal system. Many gender-specific characteristics, including biomechanical and hormonal influences, that are unique to female athletes, are thought to contribute to the greater incidence of overuse injuries in that population.
Numerous studies have shown that many female athletes are deficient in lower limb neuromuscular control, which renders them at increased risk for knee and leg injuries. The female athlete triad is defined as the contribution of a negative energy balance, inadequate calories and nutrition to support increased energy demands, to menstrual irregularities and low bone density. Athletes who participate in lean sports, such as cross-country, track and field, gymnastics, rowing, etc., may be particularly susceptible to the restrictive eating patterns that contribute to the female athlete triad, and those with a negative energy balance may also be more prone to overuse injuries.
Overuse injuries are associated with a gradual increase in symptoms, which means athletes may go undiagnosed and untreated for long periods of time. How can athletes identify these injuries sooner and intervene earlier?
Overuse injuries can occur gradually, although many athletes may not report their symptoms until their injury has progressed and either affects the ability to complete training or exerts a negative effect on performance. Developing and maintaining excellent communication between an athlete and her coach, athletic trainer and team physician can enable the early detection, treatment and management of an overuse injury. Learning to understand the warning signs of such injuries is a skill gained over time. We have found that there are fewer overuse injuries in seasoned athletes than in younger and less-experienced athletes.
What has your research, or studies by colleagues, shown about effective ways to rehabilitate overuse injuries? And, on average how long does it take to treat such conditions?
The time required for recovery from an overuse injury depends on the severity and type of that injury. Stanford student-athletes work closely with their coach and athletic trainer throughout the management of any injury, from diagnosis through recovery. Our recent research has been focused on better characterizing overuse injuries in long-distance runners so that more effective injury-prevention strategies can be developed.
In a recently published study of 748 high-school athletes aged 13 to 18 years who had participated in cross-country and track-and-field sports, we found that most of those subjects had sustained a previous overuse injury. Identifying prior overuse injury patterns can facilitate the design of specific injury-prevention protocols that will reduce the incidence of such injuries in athletes. In a separate review on calcium and vitamin D intake in young female athletes, we identified research that supports a calcium intake of 1500 mg daily and a vitamin D intake of 800 U daily to optimize bone health and lower the risk of repetitive stress fracture injuries. We are currently using nutrition logs to identify inadequate calcium intake in female long-distance runners.
Every overuse injury has its own time line for healing, although there are some general time lines for each injury. For example, a stress fracture may require as long as 3 or 4 months to heal, but mild tendinitis may resolve in a few weeks. The exact time to recovery for each injury varies with the patient and is affected by the time to diagnosis and the patient’s underlying bone and soft tissue health, nutritional status, resources for physical therapy and emotional well-being.
Adam Tenforde, MD, a second-year medical resident in physical medicine and rehabilitation at Stanford and a former All-American distance runner for the university, contributed information to this entry.
Previously: A conversation about the merits of stretching and A closer look at how stretching may benefit the body
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