Epidemiology of Hip Flexor and Hip Adductor Strains in National Collegiate Athletic Association Athletes, 2009/10-2014/15

Research Team Members: Timothy G. Eckard, PT, DPT, OCS, Darin A. Padua, PhD, ATC, Thomas P. Dompier, PhD, ATC, Sara Dalton M.Ed, LAT, ATC, Kristian Thorborg, PT, PhD, Zachary Y. Kerr, PhD, MPH

hip-adductorsWhy did you do this study?

Lower extremity muscle strains are common in collegiate sports. Strains result in significant participation restriction time for athletes, as they often require extensive rehabilitation and frequently recur. Two muscle groups vulnerable to strain injury in sports are the hip flexor and hip adductor groups. The hip flexor muscles, including the psoas major and the iliacus (i.e., the iliopsoas group), are injured in athletic activities such as sprinting, kicking, and cutting. The adductor group shares the same mechanisms of injury and consists of muscles in the medial compartment of the thigh including the pectineus, adductor magnus, adductor longus, adductor brevis, obturator externus, and gracilis. Elucidating the rates and patterns of these injuries in collegiate athletes will help determine the need for primary and secondary prevention programs in various NCAA sports. However, research on hip flexor and hip adductor strains has been mostly limited to professional athletes and frequently does not distinguish between strains of the disparate muscle groups around the hip. Therefore, the purpose of our study was to describe the epidemiology of hip flexor and hip adductor strains in 25 NCAA sports.

hip-flexorsWhat did you do and what did you find in this study?

Rates and patterns of hip flexor and hip adductor strains in collegiate sports were examined in a sample of NCAA varsity teams from 25 sports. Rates and distributions of strains by mechanism, recurrence, and time loss were examined. Rates were then compared within and between sports by event type (practice versus competition), sex, mechanism, recurrence, and time loss. A total of 770 hip flexor and 621 hip adductor strains occurred over the six academic years examined. The highest rates were in men’s soccer and men’s ice hockey. Most strains occurred in practice, but the rate of both types of strains was higher in competition. In sex-comparable sports, the hip flexor strain rate did not differ between the sexes but the hip adductor strain rate was higher in men than women. Non-contact was the most common mechanism for both types of strains, and most resulted in less than one week of time loss.

soccer-playerHow do these findings impact the public?

Our findings suggest that prevention programs for hip flexor strains should be developed and implemented across male and female sports teams, particularly in soccer and ice hockey. Male sports teams, especially soccer and ice hockey teams, should place an emphasis on prevention programs for hip adductor strains. Secondary prevention programs involving thorough rehabilitation and strict return to play criteria should be developed and implemented to curb the high recurrence rate of these injuries, particularly in ice hockey.