Jump-landing kinetic asymmetries persisted despite symmetric squat kinetics in collegiate athletes following anterior cruciate ligament reconstruction

ABSTRACT

The purpose was to determine the differences/correlations in anterior cruciate ligament (ACL) loading variables and bilateral asymmetries between injured/uninjured legs and among ascending/descending phases of double-leg squats and jumping/landing phases of countermovement jumps (CMJ) in the collegiate athletes following ACL reconstruction (ACLR). Fourteen collegiate athletes performed squats and CMJ 6-14 months following ACLR. The bilateral knee/hip flexion angles, peak vertical ground reaction force (VGRF) and knee extension moments (KEM), and kinetic asymmetries were calculated. Squats showed the greatest knee/hip flexion angles, while the landing phase of CMJ showed the least (P<0.001). The uninjured leg demonstrated greater VGRF (P≤0.010) and KEM (P≤0.008) than the injured leg in CMJ. Kinetic asymmetries were less than 10% for squats but were greater for the jumping (P≤0.014, 12%-25%) and landing (P≤0.047, 16%-27%) phases of CMJ. Significant correlations were found for KEM asymmetries between phases of CMJ (P=0.050) and squats (P<0.001). Kinetic asymmetries persisted in CMJ, while kinetic symmetries were achieved in squats in collegiate athletes 6-14 months following ACLR. Therefore, the CMJ appears to be a more sensitive assessment to monitor the bilateral kinetic asymmetries compared to squats. It is suggested to assess and screen kinetic asymmetries in different phases and tasks.

KEYWORDS:

• ACL
• re-injury
• kinematics
• rehabilitation
• countermovement jump

Acknowledgments

The authors thank the staff in the Department of Sports Medicine at the University of Wyoming for their support of this study.

Disclosure statement

The authors have no financial or personal conflicts of interest to declare. The current manuscript have not been published elsewhere or are not being considered for publication elsewhere and that the research reported will not be submitted for publication elsewhere until a final decision has been made as to its acceptability by Sports Biomechanics.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/14763141.2023.2207552.

Additional information

Funding

Yu Song’s graduate assistantship was supported by the National Science Foundation [1933409]. Yu Song also received a scholarship from the China Scholarship Council. Ling Li’s graduate assistantship was provided by the Wyoming INBRE, supported by the National Institutes of Health [P20GM103432]. Boyi Dai received funding from the National Science Foundation [1933409].