Effect of Quadriceps Femoris Muscle Fatigue after Closed Kinetic Chain Exercise on Knee Joint Proprioception

Background: Players in table tennis must adopt the semi-flexed knee position for extended periods of time, which wears down the knee joint. This fatigue adversely affects joint proprioception, which triggers sporting injuries.
Objective: This study aimed to investigate the effect of quadriceps fatigue after closed kinetic chain exercises on knee joint proprioception in table tennis players.
Materials and methods: An observational study that was conducted on 26 healthy male subjects with mean age of 23 ± 1.6 years. Fatigue protocol (FP) was induced by double legged squat until it could not be accomplished more. At 50 degrees of knee flexion, subjects were put through a weight-bearing joint position sense test. The measurements were done four times: before the FP, after the FP immediately, after 5 minutes of FP and after 10 minutes of FP by smartphone goniometer attached to the upper one third lateral section of the dominant leg.
Results: Multiple pairwise comparison tests (Post-hoc tests) showed statistically significant lower knee position sense values immediately after fatigue in comparison with before fatigue values (p-value = 0.002), while there was non-significant difference between before fatigue in comparison with after 5 min and after 10 min of fatigue (p-values = 0.263 and 0.117 respectively).
Conclusion: A study revealed that quadriceps fatigue after closed kinetic chain exercises had affected knee joint proprioception in table tennis players and 5 minute recovery was enough for proprioceptive recovery.