Comparison between grip strength and relative grip strength in their relationship with allostatic load among adolescents.

Purpose: To assess the associations of muscle strength, measure by grip strength and relative grip strength (grip strength divided by body weight), on the allostatic load (AL) index in adolescent boys and girls.

Methods: A total of 1,323 students were recruited (boys = 776, girls = 547). Data on general demographic characteristics, anthropometric indicators, grip strength, blood pressure, pulse rate, and biological samples were collected. A 20-indicator-based AL index (using the AL, AL, and AL calculation methods) was used as the dependent variable. Multiple linear regression models were used to evaluate the association between grip strength, relative grip strength, and AL. All analyses were stratified by sex.

Results: The mean age of the participants was 14.17 ± 1.45 years. Overall, the linear regression model adjusting for demografic characteristics showed that greater grip strength was associated with higher AL scores (R = 10.1%, β = 0.096, P < 0.001). Then, we further adjusted for body weight, and negative associations were observed between grip strength and AL (R = 35.3%, β = -0.027, P = 0.030). However, after sex stratification, this association was not statistically significant in girls. Moreover, relative grip strength was negatively associated with AL (R = 14.8%, β = -8.529, P < 0.001) after adjusting for demographic characteristics in the total sample. Specifically, relative grip strength was more strongly associated with the AL burden in boys than in girls. Finally, sensitivity analyses of AL and AL yielded similar results.

Conclusion: We observed that compared with grip strength, relative grip strength might be a useful indicator for the identification of AL burden in adolescents. The results suggest that strengthening relative handgrip strength in adolescents might help reduce the AL burden, especially in boys.