One third of people exert greater handgrip strength with their non-dominant hand.

It is unknown whether non-dominant handgrip strength is more strongly associated with health-related quality of life than dominant handgrip strength. This analytical cross-sectional study aimed to determine the comparative association of dominant versus non-dominant handgrip strength with health-related quality of life. Bilateral handgrip strength assessments were performed, and health-related quality of life was assessed using the Short Form-36 questionnaire. A total of 229 participants were evaluated (49.6 ± 5.2 years; 29.9 ± 4.73 kg/m2; 52.8% female; 96.1% right-handed). Dominant handgrip strength (33.00 ± 10.66 kg) was significantly stronger than non-dominant handgrip strength (31.30 ± 9.74 kg; p < 0.001). Notably, in the total population, 32.3% (n = 74; 33.0 ± 10.1 kg) obtained their maximum grip strength in the non-dominant hand, whereas 67.7% (n = 155; 34.2 ± 10.9 kg) obtained it in the dominant hand. Both dominant (rω = 0.31; p < 0.001) and non-dominant (rω = 0.31; p < 0.001) handgrip strength showed significant and near-identical positive correlations with health-related quality of life. Linear regression models were statistically significant and showed that non-dominant (β = 0.32; p < 0.001) and dominant handgrip strength (β = 0.31; p < 0.001) explained 9.8% and 10.2% of the variance in health-related quality of life, respectively. In conclusion, non-dominant handgrip strength was significantly associated with health-related quality of life, with a magnitude almost identical to that of dominant handgrip strength. These findings challenge the common clinical and investigative practice of assessing only the dominant hand; given that nearly one-third (32.3%) of participants were strongest in their non-dominant hand, unilateral assessment protocols risk systematically underestimating true maximum strength and misclassifying individuals.