Changes in the continuous leaping performance of Finnish adolescents between 1979 and 2020

The aims of this secular trend design study were: 1) to investigate whether the continuous leaping performance of Finnish adolescents (mean age 14.99 ± .61 years) changed between 6 data sets collected between 1979 and 2020, and 2) to analyse if variation in leaping performance increased from 1979 to 2020. The data for this secular trend study of 6 cohorts were collected in 1979 (n = 599), 1995 (n = 498), 1998 (n = 796), 2003 (n = 2383), 2010 (n = 1383), and 2020 (n = 719). All cohorts performed the 5-leaps test, following the same protocol. Between-cohort differences in scores were analysed using a General Linear Contrast Model. Between-cohort differences in variance were tested using Chi-square-based between-group tests. Sex, age, and BMI were used as covariates in the secular trend analyses. Continuous leaping performance demonstrated a decreasing trend in both girls and boys. Specifically, girls' scores were stable between 1979 and 1995, decreased from 1995 to 2010 and remained stable thereafter. Boys leaping performance improved from 1979 to 1995, was stable until 2003, and had declined by 2020. Within-group variation in continuous leaping was greater in girls and boys during the first decades of the 21st century than previously.