Proprioception and Central Nervous Excitability: Implications for Return-to-Play in Athletes with Ligament or Meniscal Injuries.

Background and Purpose: While indicators such as joint stability, range of motion, and muscle strength are critical for assessing readiness to return to sports, athletes may still face challenges even when these benchmarks are met. Therefore, this study aimed to examine the relationship between sports injury history or return-to-play status and central nervous system excitability during muscle output adjustments, and to investigate the characteristics of evoked EMG during torque maintenance as a potential indicator for assessing readiness to return to sport. Design: Case control, observational study. Methods: Twenty-one female university basketball players participated, including athletes with and without a history of surgery. Participants were eligible if they had no current injuries. Those with a history of surgery had completed rehabilitation and were cleared for return to play. Subjects were instructed to maintain 25% of maximum effort of voluntary isometric contraction of knee extension and the torque, long-latency reflexes (LLR) were recorded. Torque maintenance was assessed under two conditions: visual feedback and verbal instructions. Frequency of LLR appearance, and an average of latency, duration, amplitude ratio, and number of phases were calculated. Comparisons were made using Wilcoxon signed-rank tests between the dominant and non-dominant legs, and in participants with a history of injury, comparisons were also made between the injured and non-injured legs. Results: The visual feedback condition led to finer motor adjustments in uninjured knees compared to verbal feedback. For injured knees, the amplitude ratio of LLR was significantly higher with visual feedback, indicating increased central nervous system excitability. Athletes who had not returned to sports displayed greater torque fluctuation and lower LLR amplitudes, suggesting inadequate fine motor control. Conclusion: These findings suggest that visual feedback enhances motor adjustments in athletes with previous injuries, indicating heightened reliance on central nervous functions. Level of Evidence: 3b.