Squat Jump and Bilateral and Unilateral Countermovement Jump Performance in Soccer Players 6 and 9 Months After...

Background and Objectives: The assessment of neuromuscular recovery after ACL reconstruction is crucial for safe return to sport (RTS) in professional soccer players. This retrospective cross-sectional study aimed to compare squat jump (SJ), bilateral countermovement jump (CMJ), and single-leg CMJ performance in three distinct groups: players at 6 months post-ACL reconstruction, players at 9 months post-ACL reconstruction, and healthy controls. Materials and Methods: Seventy-two male players (24 at 6 months post-ACL, 24 at 9 months post-ACL, 24 healthy controls) performed squat jump, bilateral countermovement jump, and single-leg CMJ tests using contact platforms following a controlled warm-up protocol. Results: Significant group differences were observed in all jump tests. At 6 months post-ACL reconstruction, players demonstrated significantly lower squat jump (45.13 ± 6.20 cm) and bilateral countermovement jump (49.67 ± 6.80 cm) heights compared to both 9-month players (SJ: 50.03 ± 5.30 cm; CMJ: 53.79 ± 4.85 cm) and controls (SJ: 51.12 ± 4.97 cm; CMJ: 55.49 ± 5.54 cm) (p ≤ 0.016, η² = 0.187 and η² = 0.156, respectively). No significant differences between 9-month and control groups were observed for the squat jump and the bilateral countermovement jump. Regarding the unilateral countermovement jump, the injured leg showed significant performance deficits compared to controls in both the 6-month and 9-month groups (p = 0.001, η² = 0.378). However, the non-injured leg exhibited deficits only in the 6-month group. Conclusions: Compared to the 6-month post-ACL reconstruction group, the 9-month group showed a marked improvement in bilateral jump performance, indicating substantial neuromuscular recovery over time. However, persistent unilateral deficits in the injured leg remained even at 9 months, underscoring the need for a routine and comprehensive jumping evaluation to identify residual neuromuscular impairments that may require targeted rehabilitation before returning to sport.