Impact of Biomechanical, Anthropometric, and Temporal Factors on the Return-to-Sport Rate in Recreational Athletes with ACL Reconstruction: A Cross-Sectional Observational Study

<b>Background/Objectives</b>: Anterior cruciate ligament reconstruction (ACLR) necessitates evidence-based rehabilitation strategies to optimize return-to-sport (RTS) outcomes, yet persistent re-injury rates and suboptimal performance persist despite standardized protocols. The purpose of this cross-sectional observational study is to examine the relationship between biomechanical, anthropometric, and temporal factors and return-to-sport outcomes. <b>Methods</b>: This cross-sectional study identifies biomechanical, anthropometric, and temporal determinants of RTS readiness in 81 recreational athletes post-ACLR. Outcome measures included anterior (A-SLH), lateral (L-SLH), and medial (M-SLH) single-leg hop for distance, single-leg sit-to-stand (SLSS), single-leg wall-sit hold (SLWS), and ACL-RSI. Statistical analyses employed Spearman's correlations and multiple linear regression to determine the predictors of ACL-RSI. <b>Results</b>: There were significant correlations between RSI and Limb Symmetry Index (LSI) for L-SLH, M-SLH, SLSS, and SLWS (r = 0.27, r = 0.30, r = 0.44, r = 0.34, and <i>p</i> < 0.01, respectively). Among the functional outcome measures, multiple linear regression revealed that only SLWS significantly predicted ACL-RSI (β = 0.248, <i>p</i> = 0.037). Also, body weight (β = -0.233, <i>p</i> = 0.030) and postoperative duration (β = 0.292, <i>p</i> = 0.006) significantly predicted ACL-RSI. <b>Conclusions</b>: These findings challenge the primacy of limb symmetry indices alone, emphasizing the role of weight management, time-dependent neuromuscular adaptation, and multi-planar closed-chain strength in RTS decision-making. Clinically, rehabilitation frameworks should integrate personalized strategies targeting body composition and dynamic stability to mitigate asymmetric joint loading and enhance functional resilience.