The Effects of Joint Hypermobility on Strength, Proprioception, and Functional Performance

Background: Generalized Joint Hypermobility (GJH), assessed using the Beighton scoring system, is characterized by increased joint mobility and is often associated with proprioceptive deficits, reduced muscle strength, and functional impairments. Understanding its impact on physical performance is essential for developing targeted interventions. Aims: The primary aim of this study is to investigate the relationship between Beighton scores and grip strength, elbow and knee proprioception, as well as upper and lower extremity performance. The secondary aim is to compare hypermobile individuals (Beighton scores 4-9) and non-hypermobile individuals (Beighton scores 0-3) in terms of these parameters, highlighting differences in proprioception, strength, and functional outcomes. Methods: A total of 83 participants, divided into hypermobile (n:46) and non-hypermobile (n:37) groups based on their Beighton scores, were assessed. Measurements included grip strength, proprioceptive accuracy at the elbow and knee joints, and functional performance evaluated using the Closed Kinetic Chain Upper and Lower Extremity Stability Tests. Data were analyzed to determine correlations between parameters and to compare the two groups. Results: The hypermobile group demonstrated notable proprioceptive deficits in both upper and lower extremities compared to the non-hypermobile group (p˂0.05). The other measurements showed no significant differences between groups. In the hypermobile group, significant positive correlations were observed between Beighton scores and dominant hand grip strength, elbow proprioception at 30°, knee proprioception at 30°, and knee proprioception at 60° (r = 0.674, r=0.422, r = 0.448, r = 0.624, respectively and p < 0.05 for all). However, no associations of the Beighton score with elbow position sense at 60°, CKCUEST and CKCLEST in the hypermobile group. Conclusions: This study underscores the dual nature of GJH, where increased joint mobility enhances specific strength measures but contributes to proprioceptive deficits. However, functional stability, as assessed through CKCUEST and CKCLEST, was not significantly different between hypermobile and non-hypermobile individuals, suggesting that hypermobility alone may not be a determining factor for functional performance in these tasks. These findings emphasize the need for targeted neuromuscular and proprioceptive training to reduce injury risks and optimize functional outcomes in hypermobile individuals.