IS DECELERATION THE KEY ELEMENT IN VERTICAL JUMP PERFORMANCE TO RETURN TO SPORT AFTER ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION?

Introduction: After anterior cruciate ligament reconstruction (ACLR), jump tests allow to help return to sport decision making. Objective: The main objective was to examine countermovement jump (CMJ) measures to identify which parameters can best distinguish between ACLR and control participants. The secondary objective was to determine whether performance alterations between operated and non-operated limb exist during vertical two-legged activities after ACLR Design: Non randomized, single blinded, prospective case control study Methods: This study included 67 patients with hamstring graft and no contact injury at 6 postoperative months (203.5 days ± 32.2) and 47 healthy athletes (25,2 ± 6,6 years old) with no knee injury history. Two groups were formed, an ACLR group (n=67) and a control group (n=47). The evaluation of CMJ by force plate was performed to calculate vertical ground reaction force (vGRF), maximal power (MP) and eccentric rate force development (RFDe) during landing and limb symmetry index (LSI). (1-3) First analysis compared LSI vGRF, LSI MP and LSI RFDe between both groups during CMJ. Secondary analysis compared vGRF, MP and RFDe between operated/non-operated limb in the ACLR group and dominant/non-dominant limb in the control group. Results: At 6 months after ACLR, CMJ measures in the ACLR group were significantly reduced compared to the control group for LSI vGRF (- 8.7% ; p < 0,001), LSI MP (- 10.8% ; p < 0,001) and LSI RFDe (- 8.7% ; p < 0,001). Secondary analysis showed no significant result in control group between dominant/non-dominant limb. ACLR group showed significant results between operated / non-operated limb for vGRF (+1.4 N.kg-1 ; p < 0,001), MP (+2.6 W.kg-1 ; p < 0,001) and RFDe (+ 375.3 N.s-1 ; p < 0,01). Conclusion: Landing performance and deceleration should be better considered at time to return to sport after ACLR. [ABSTRACT FROM AUTHOR]