The counteracting effect of the friction moment against the tibial rotational moment driven by the ground reaction force in an early stance phase of cutting maneuver among healthy male athletes.

The ground reaction force (GRF) is known to produce tibial internal rotation loading associated with the stress in the anterior cruciate ligament (ACL). However, it is unclear whether the friction moment (FM; the moment due to horizontal shoe-floor friction, acting around the vertical axis at the GRF acting point) facilitates or restrains the effect of GRF-driven tibial rotation loading during cutting. The 45° cutting motions with forefoot/rearfoot strikes were captured simultaneously with GRF and FM data from 23 healthy males.

Effect of the foot-strike pattern on the sagittal plane knee kinetics and kinematics during the early phase of cutting movements.

Anterior cruciate ligament (ACL) injury occurs soon after foot-strike. Cutting with a shallow flexed knee is considered a risk factor for ACL injury; however, how foot-strike patterns (forefoot strike [FFS] vs. rearfoot strike [RFS]) affect sagittal plane knee kinetics and kinematics after a foot-strike, is unknown.