Running Gait Biomechanics Profiles Associated With Tibial Bone Stress Injury Among Adolescent Athletes

PURPOSE: Tibial bone stress injuries (BSI) are common in adolescent runners, however no studies have evaluated running biomechanics associated with tibial BSI in adolescents. The purpose of this study was to compare running biomechanics between adolescents with and without history of tibial BSI. METHODS: This was a retrospective case-control study of 83 athletes with history of tibial BSI (62 female, 21 male; age: 16.2 ± 1.9 yrs, BMI: 21.7 ± 2.6 kg/m2) and 83 healthy age- and sex-matched controls (BMI: 21.4 ± 2.3 kg/m2). Case group participants included male and female runners (age 10-18 yrs) diagnosed with tibial BSI by MRI and/or X-ray. After medical clearance for return to run, case group athletes underwent running biomechanics analyses on a force plate treadmill with integrated sagittal and coronal plane video. Healthy control runners had running biomechanics analyses with the same protocol. Tibial BSI participants’ case limbs (or worse limbs for bilateral injury cases) were matched to healthy control limbs. Analyses of variance were used for group demographics and continuous outcomes, and Chi-square analyses were used to compare categorical outcomes. Effect sizes were calculated post-hoc for significant findings (α = 0.05). RESULTS: The tibial BSI group had lower swing phase % of gait cycle [Mean Difference Standard Error (MD): -1.66 ± 0.86%; p = 0.05, d = 0.27], less foot rotation (MD: -1.89 ± 0.71°, p = 0.009, d = 0.37), greater maximum vertical Ground Reaction Force (vGRF) (MD: 0.08 ± 0.04 BW, p = 0.01, d = 0.28), and more supinated foot landing positions (77.4 vs. 58.1%, Χ2 = 9.2, p = .002). Other demographic and gait outcomes did not differ between groups. 35% of patients had bilateral tibial BSI, and most were Fredericson Grade 2/4 injuries (44%). All patients were treated with impact restriction; 40% with unilateral walking boots (27 ± 15 days). There was a median (IQR) of 123 (39, 326) days elapsed between clearance for return to run and date of gait analysis. CONCLUSIONS: We identified key biomechanical differences in adolescents with history of tibial BSI versus those without, including greater maximal vGRF loading and a lower gait cycle percentage in swing phase (i.e., a more terrestrial gait pattern). These findings offer potential biomechanics targets in the prevention and treatment of tibial BSI in adolescents.