Comparative Biomechanical Strategies of Running Gait Among Healthy and Recently Injured Pediatric and Adult Runners

Biomechanical strategies of running gait were compared among healthy and recently injured pediatric and adult runners (N = 207). Spatiotemporal, kinematic, and kinetic parameters (ground reaction force [GRF], vertical average loading rate [VALR]) and leg stiffness (K_vert) were obtained during running on an instrumented treadmill with simultaneous 3D-motion capture. Significant age X injury interactions existed for cadence, peak GRF, and peak joint angles in stance. Cadence was fastest in healthy adults and 2-3% lower in other groups (<i>p</i> = 0.049). Injured adults exhibited higher variance in stance and swing time, whereas injured pediatric runners had lower variance in these measures (<i>p</i> < 0.05). Peak GRF was highest in non-injured adults (2.6-2.7 BW) and lowest in injured adults (2.4 BW; <i>p</i> < 0.05). VALRs (BW/s) were higher among pediatric groups, irrespective of injury (<i>p</i> < 0.05). The interaction for ankle dorsiflexion/plantarflexion moment was significant (<i>p</i> = 0.05). Healthy pediatric runners produced more plantarflexion than all other groups (<i>p</i> = 0.026). Pelvis rotation was highest in healthy pediatric runners and lowest in healthy adults (17.3° versus 12.0°; <i>p</i> = 0.036). Pediatric runners did not leverage force-dampening strategies, but reduced gait cycle time variance and controlled pelvic rotation. Injured adults had lower GRF and longer stance time, indicating a shift toward force mitigation during stance. Age-specific rehabilitation and gait retraining approaches may be warranted.