Secular trends and sociodemographic, biological, and behavioural factors associated with handgrip strength in adolescents in southern Brazil: An allometric approach.

The purpose of this study was to analyse secular trend in handgrip strength (HGS) in adolescents using an allometric approach and identify the factors associated. The sample comprised 657 and 1004 adolescents (14 to 19 years) in 2007 and 2017/2018, respectively, of public schools in Florianópolis, Brazil. The dependent variable was HGS normalised to body mass and height. Covariance analysis was used to examine secular trends in HGS, and multiple linear regression was used to identify associated factors. The independent variables were sociodemographic, biological, and behavioural factors. Comparison of HGS between surveys indicated a negative secular trend in both sexes ( < 0.001). In boys, there was a positive association of HGS with age and FFM in both surveys. In 2017/18, there was a positive association with sexual maturation and a negative association with sitting time and fat percentage. In girls, FFM was positively associated with HGS in both surveys. In 2007, there were positive associations of HGS with age and vigorous physical activity, whereas, in 2017/18, negative associations were observed with economic level and sitting time. The findings of the present study show a decline in adolescent HGS. And behavioural changes appear to be contributing to declines in HGS.