Wearable technology identifies differences in change of direction kinetics and kinematics in soccer players with a history of anterior cruciate ligament reconstruction.

Abstract

This study investigates change of direction (COD) performance and biomechanics using wearable technology in athletes with a history of anterior cruciate ligament reconstruction (ACL-R) compared to healthy controls. A within and between subjects' cross-sectional design was used. The sagittal plane kinematics of the hip, knee, and ankle during 90° side-step cutting were measured with inertial measurement units, while the vertical force was recorded with insoles in the players' boots. Twenty-six professional soccer players participated (mean age 22.7 ± 3.7 years, height 177.8 ± 5.1 cm, weight 69.4 ± 8.5 kg). Sixteen players were healthy controls, and 10 were in a full-time ACL-R rehabilitation programme, assessed 9 months post-surgery. Mixed model analysis and statistical parametric mapping were used to compare COD completion time, kinetics, and kinematics between limbs (involved vs. uninvolved) and groups (ACL-R vs. controls) during the penultimate and final foot contacts. No significant differences in COD completion time were found between limbs (p = 0.52, d = 0.22) or groups (p = 0.65, d = 0.51). However, during the penultimate foot contact, the involved limb exhibited greater ankle dorsiflexion compared to the uninvolved and controls from 48% to 100% of stance (p = 0.002, d = 0.94-1.86), with lower vertical force production (p > 0.05, d = 0.81-0.95). During the plant step, lower knee flexion angles were noted compared to the uninvolved limb and controls from 2% to 69% of stance (p = 0.011, d = 1.26-1.31). The findings suggest that soccer players with ACL-R can restore COD completion time at the time to return to sport. However, they used compensatory movement strategies on the involved side to achieve similar performance, and this must be considered from a rehabilitation standpoint. Level III.