Vertical jump asymmetries from 6 to 9 months following anterior cruciate ligament reconstruction with hamstring tendon autograft in non-elite athletes

Abstract

Purpose

To investigate how bilateral vertical jump performance and kinetic asymmetries change from 6 to 9–12 months following anterior cruciate ligament reconstruction (ACLR).

Methods

Ninety-one non-elite athletes who underwent ACLR via hamstring tendon autograft performed bilateral countermovement jumps (CMJs) and drop jumps (DJs) on dual force plates at 6 and 9–12 months post-surgery. Performance outcomes and kinetic variables, including asymmetry indices (AIs), were analysed using mixed models to investigate changes between the two time points.

Results

Jump height and reactive strength for both the CMJ and DJ improved between the two time points (p ≤ 0.001). Concentric impulse of the CMJ was the only variable to show a significant between-limb change over time (p ≤ 0.05), which was mainly due to a reduction in the nonoperative limb while the operated limb remained unchanged for both. No significant between-limb changes over time for any DJ variables (p > 0.05). AIs for concentric and eccentric impulse, for both the CMJ and DJ, reduced over time (p ≤ 0.05), except for peak landing force in the CMJ.

Conclusions

Non-elite athletes after ACLR demonstrated improvements in jump height and reactive strength from 6 to 9–12 months post-surgery, while improvements in eccentric and concentric between-limb asymmetries for both the CMJ and DJ were primarily due to a reduction in the nonoperated limb.

Level of Evidence

Level IV.