Relationship between Stance Frontal Plane Kinematics and Initial Impact forces in Runners: Asymmetry Implications

Abstract

Rearfoot eversion (REV) and contralateral pelvis drop (CPD) play a crucial role in force absorption at impact during running. Controlling and adequately absorbing the repetitive vertical ground reaction force (vGRF) at impact is essential in injury prevention. PURPOSE: This study aimed to examine the relationships between vGRF and REV, and vGRF and CPD bilaterally in collegiate runners. METHODS: Eleven asymptomatic (5 females, 6 males) NCAA Division II cross country runners (age, 19.1 ± 1.1 yrs; height, 174.2 ± 11.2 cm; mass 62.2 ± 6.2 kg; 38.3 ± 15.9 miles/wk, treadmill speed, 3.6 ± 0.5 m/s) underwent 3D motion analysis during a 7 minute steady state run on an instrumented treadmill. vGRF, REV and CPD were evaluated bilaterally for association via Pearson Correlation coefficients, p<0.05. RESULTS: Mean (+SD) peak angles of REV and CPD, and vGRF during left stance were 3.6 ± 6.5°, -5.4 ± 3.8°, and 1.8 ± 0.6 body weights (BW), respectively. Mean peak angles of REV and CPD, and vGRF during right stance were 2.51 ± 2.5°, -4.9 ± 4.9°, and 1.6 ± 0.4 BW, respectively. Significant high negative correlation was found for REV and vGRF during left stance [r (9) = -.967, p=0.03] while CPD and vGRF during right stance were significantly highly positively correlated [r (9) .714, p=0.02]. CONCLUSION: Despite the low number of subjects, we conclude that frontal plane kinematics are associated with impact force magnitude during running, and the associations appear to be asymmetrical necessitating a bilateral examination of running mechanics.