Factors Contributing to the Development of Medial Tibial Stress Syndrome in High School Runners

STUDY DESIGN: Predictive correlational study. OBJECTIVES: To identify the incidence of medial tibial stress syndrome (MTSS) in a group of high school cross-country runners and to determine if a relationship exists between lower extremity structural measures and the incidence of MTSS. BACKGROUND: Medial tibial stress syndrome is an overuse injury that occurs in long-distance runners. Literature exists that implicates structural deformity as a contributor to MTSS, but no studies have developed a predictive model. METHODS AND MEASURES: We measured 125 high school cross-country runners for tibiofibular varum, resting calcaneal position during stance, and gastrocnemius length. Runners developing MTSS over an 8-week period were placed in the injured group (2 men, 13 women; age 15.3 years 1.0), and 21 randomly selected uninjured runners were placed in the uninjured group (13 men, 8 women; age 15.7 years +/-1.5). Navicular drop was measured for runners in both groups. Reliability of measures was determined using an intraclass correlation coefficient (ICC 3,1). Paired t tests were used to compare the injury and noninjury groups. A logistic regression analysis was used to establish if the descriptive data could accurately predict the development of MTSS. RESULTS: Paired t tests showed a significant difference in navicular drop test measures between the injured (6.8 mm 3.7) and noninjured (3.6 mm 3.3) groups. Logistic regression analysis revealed navicular drop test measurements and sex correctly identified athletes who developed MTSS with 76% accuracy. CONCLUSION: Our study supported the hypothesis that a pronatory foot type is related to MTSS. The combination of sex and navicular drop test measures provides an accurate prediction for the development of MTSS. Clinical measures that identify biomechanical risk factors for MTSS may allow prevention or early intervention.