Compensatory Movement Strategies during the Rearfoot Elevated Split Squat after ACL Reconstruction

Area of Science:

• Biomechanics
• Orthopedics
• Sports Medicine

Background:

• Anterior cruciate ligament (ACL) reconstruction requires careful rehabilitation to restore function.
• The rearfoot elevated split squat (RFESS) is commonly used in ACL rehabilitation for knee extensor strengthening.
• Understanding compensatory movement strategies is crucial for optimizing rehabilitation outcomes.

Purpose of the Study:

• To compare inter- and intra-limb compensation strategies between ACL-involved and non-involved limbs during the RFESS.
• To examine how trunk flexion angle influences these compensation strategies.

Main Methods:

• Twenty-five individuals post-ACL reconstruction performed RFESS.
• Three-dimensional motion capture and force plates were used to analyze joint kinematics, kinetics, and ground reaction forces.
• Paired t-tests and linear regression analyzed between-limb differences and the effect of trunk flexion.

Main Results:

• The ACL-involved limb showed altered loading patterns, with reduced vertical ground reaction forces and knee joint moments.
• A shift in load towards the hip and ankle joints was observed in the ACL-involved limb.
• Increased trunk flexion correlated with higher vertical ground reaction forces but not knee contribution.

Conclusions:

• ACL-involved limbs exhibit inter- and intra-limb compensation during RFESS.
• A more upright trunk posture during RFESS may increase inter-limb compensation and lead to greater offloading of the affected limb.
• The RFESS may not effectively strengthen knee extensors in mid-stage ACL rehabilitation without careful monitoring due to these compensatory strategies.