Influence of Manipulating Running Foot Strike Angle on Internal Loading of the Tibia.

Tibial stress injuries are problematic among runners. Foot strike pattern upon landing may alter internal tibial loading, which could potentially affect the risk of stress injuries during running. The purpose of this study was to quantify internal loading at the distal 1/3 of the tibia during running with imposed rearfoot and forefoot strikes. Nineteen habitual rearfoot strikers were recruited to run with their preferred foot strike and then with imposed rearfoot and forefoot strikes in a randomly assigned order. Force and motion capture data were collected synchronously, and the foot strike in the sagittal plane was identified from the kinematic data. The tibial bending moments were estimated using musculoskeletal modeling and beam theory, and cumulative-weighted tibial impulse per kilometer was derived. Significant differences in peak bending moments were found among foot strike patterns (p < 0.001). Running with an imposed forefoot strike increased tibial loading, especially during early to mid-stance (2%-67% stance, p < 0.001). However, imposed rearfoot striking resulted in lower bending moments than both habitual rearfoot striking (p < 0.001) and forefoot striking (p < 0.001). Additionally, cumulative-weighted impulse per kilometer was significantly greater when running with an imposed forefoot strike compared to both habitual (p = 0.001) and imposed rearfoot strikes (p < 0.001). Running with an imposed nonhabitual forefoot strike results in higher tibial loading than rearfoot striking due to increased mechanical demands placed on the plantar flexors. Transitioning from a habitual rearfoot strike to a forefoot strike may not be advisable for runners aiming to reduce tibial loading.