Examining the relationship between extensor carpi radialis brevis pennation angle and grip strength. A cross-sectional study

Background. This cross-sectional study aimed to investigate the relationship between the pennation angle of the extensor carpi radialis brevis (ECRB PA) and grip strength. Additionally, the study explored potential gender differences in ECRB PA and its association with grip strength. Methods. A total of 155 healthy participants were recruited. Ultrasound imaging was used to measure the ECRB PA, while grip strength was assessed using a Jamar dynamometer. Statistical analysis was conducted to examine the correlation between ECRB PA and grip strength. Results. ECRB PA and common extensor tendon (CET) thickness correlated significantly with grip strength, showing gender-specific patterns. In males, ECRB PA had a moderate positive correlation with grip strength (r = 0.474), and CET thickness showed a strong correlation (r = 0.714), suggesting that both factors contribute to grip strength. In females, ECRB PA correlated moderately with grip strength (r = 0.585), while CET thickness showed a weak inverse correlation (r = –0.136). These findings suggest that CET thickness may indirectly reflect physiological cross-sectional area (PCSA) and influence grip strength in males, whereas ECRB PA plays a more critical role in females. Conclusion. This cross-sectional study provides evidence of a correlation between ECRB PA and grip strength in healthy individuals. The findings suggest that individuals with a larger ECRB PA may have reduced grip strength. Furthermore, the observed gender differences in ECRB PA could partially explain variations in grip strength between males and females. Further research is needed to validate these findings in clinical populations with wrist and hand pathologies.