Author(s): WILKE, C., MATUSZEWSKI, L., ABEL, R., Institution: GERMAN SPORT UNIVERSITY COLOGNE, Country: GERMANY, Abstract-ID: 635

INTRODUCTION:
Rupture of the anterior cruciate ligament (ACL) can make it difficult to return to high-performance sports such as artistic gymnastics, even after completing rehabilitation. Functional performance tests are essential for monitoring the load tolerance of injured structures, and can indicate when it is appropriate to return to sport (Dingenen und Gokeler, 2017). A Limb Symmetry Index (LSI) of at least 90% is often cited in the literature as a criterion for evaluating knee function. This study investigates the time at which the functional performance (FP) and LSI of a gymnast following an ACL injury return to pre-injury levels, thereby indicating their readiness to return to sport. A 6-year follow-up was conducted to assess long-term sustainability.
METHODS:
One elite female artistic gymnast (aged 24, with 18 years of training experience at a natio-nal competitive level) completed four functional tests — the Y-Balance Test (YBT), the Single-Leg Countermovement Jump Test (SLCMJ), the Single-Leg Hop for Distance Test (SLH) and the Speedy Jump Test (SJ) — at nine time points: t1 = 10 months pre-injury, t2 = 2 months post-injury, t3 = 2 months post-surgery, t4–t8 = 4 to 12 months post-surgery (bimonthly), and t9 = 6 years post-surgery Data were analysed descriptively using the LSI. At t9 an additional isokinetic strength measurement was performed at 60°/s, 180°/s, and 300°/s.
RESULTS:
At eight months (SLCMJ and SJ) and ten months (SLH) post-trauma, the LSI reached ≥90% across all tests. For the YBT, the LSI remained ≥90% from t1 to t9. Pre-injury FP levels were reached after 12 months for the SLCMJ and SJ. At t9, the LSI for the SJ was 92%, which was lower than the pre-injury value; however, all other tests showed values comparable to those at t1. Functional performance values declined at t9. The isokinetic results were 58.8/70.5/96.0% on the left leg and 55.5/74.1/85.3% on the right leg (60°/s, 180°/s, 300°/s).
CONCLUSION:
Readiness to return to sport was identified at 10 months post-surgery, with no subsequent injury during follow-up. As declines in the uninjured limb may limit the interpretability of the LSI, absolute functional performance should also be considered. In particular, outcomes from the dynamic Speedy Jump test and long-term monitoring using the Reliable Change Index are recommended. Right-sided hamstring weaknesses and slight asymmetries in the strength profile 6 years post- surgery pose risks. This case study highlights the importance of regular performance testing in order to obtain pre-injury reference data and optimise preventive and therapeutic training strategies. Further longitudinal studies incorporating absolute performance measures are needed to confirm these findings.

Dingenen, B., Gokeler, A. (2017). Optimization of the Return-to-Sport Paradigm After Anterior Cruciate Li-gament Reconstruction: A Critical Step Back to Move Forward. Sports Med 47, 1487–1500. https://doi.org/10.1007/s40279-017-0674-6