Association between Segmental Muscle Mass and Handgrip Strength in Healthy Young Adult Males: A Cross-Sectional Study

Background: Body composition assessment using bioelectrical impedance analysis (BIA) provides valuable insights into nutritional status by estimating body protein and fat composition. BIA also uses predictive equations to estimate muscle mass across different body segments, including the right arm, left arm, trunk, right leg, and left leg. Handgrip strength (HGS), measured using a handheld dynamometer, is a widely accepted indicator of muscle strength; however, it primarily reflects upper-limb strength and is often used as a surrogate for overall muscle strength. This study examined the relationship between BIA-estimated segmental muscle mass and HGS in healthy young males. Methods: Forty healthy male participants aged 18–25 years with a normal body mass index were recruited. Total and segmental muscle mass were assessed using a BIA analyser, and HGS was assessed on the dominant hand with a handheld dynamometer. Pearson's correlation analysis was performed to evaluate the associations between BIA-estimated total and segmental muscle mass and HGS. The Holm procedure was applied to control the family-wise error rate across the six correlation tests. Results: BIA-estimated total muscle mass was positively correlated with HGS (r = 0.461, p = 0.003). Significant positive correlations were also observed between HGS and BIA-estimated muscle mass in all body segments. The strongest correlation was found for the left arm (r = 0.521, p < 0.001), whereas the weakest was observed for the right leg (r = 0.373, p = 0.018). However, formal statistical comparison of dependent correlations was not performed, and the 95% confidence intervals for these correlations overlapped. Conclusion: HGS was significantly associated with both total and segmental BIA-estimated muscle mass in healthy young males. Although muscle mass across all five assessed body segments was significantly associated with HGS, the magnitude of these associations appeared to differ across anatomical regions, with numerically stronger associations observed for the arm segments and weaker associations for the lower-limb segments. These segmental comparisons should be interpreted as exploratory.