Study of Wrist Joint Movements, Hand Dimensions, and Comparison to Grip Strength Among Omani Medical Students: A Pilot Study.

Background: Wrist joint position and hand anthropometric measurements may affect grip strength and hand performance. This pilot, analytical cross-sectional study aimed to investigate the relationship between different wrist positions and grip strength, as well as the association between grip strength and hand size in healthy individuals. Methods: An analytic cross-sectional study was conducted with undergraduate medical students. We assessed grip strength using a hand dynamometer in different wrist positions, including wrist flexion, extension, ulnar deviation, and radial deviation. Hand anthropometric measurements, including HB, MHB, PL, TFL, IFL, MFL, RFL, and LFL, were performed using a sliding digital caliper. Results: Grip strength varied significantly across wrist positions, with the highest mean value observed in the neutral position (30.53 kg), followed by ulnar deviation (28.94 kg), radial deviation (18.02 kg), extension (14.75 kg), and flexion (14.67 kg). The repeated-measures ANOVA demonstrated significant main effects of wrist position and sex, as well as a significant interaction between wrist position and sex (all p < 0.001). Males demonstrated higher mean grip strength than females in the neutral position (42.56 ± 8.98 kg vs. 18.54 ± 4.20 kg, respectively). Grip strength measurements across wrist positions showed strong positive correlations, with the strongest associations observed between flexion and neutral grip strength (ρ = 0.84) and between ulnar deviation and neutral grip strength (ρ = 0.81). The wrist angle was negatively correlated with grip strength during flexion (ρ = -0.24, p < 0.05) and extension (ρ = -0.41, p < 0.05), representing weak and moderate associations, respectively. Females demonstrated greater mean flexion and extension than males, whereas males demonstrated higher mean values for ulnar and radial deviation. Among males, grip strength was significantly positively correlated with maximum hand breadth (ρ = 0.365, p = 0.001), hand breadth (ρ = 0.326, p = 0.003), palm length (ρ = 0.304, p = 0.006), thumb length (ρ = 0.289, p = 0.009), and index finger length (ρ = 0.229, p = 0.039). No statistically significant associations were observed between grip strength and the assessed hand anthropometric measurements among females. Conclusions: Grip strength is markedly influenced by wrist position, with the highest grip strength measured in the neutral position and decreased in flexion, extension, or radial deviation. The results of this study may have implications for rehabilitation, ergonomic design, and sports performance in the future.