Reference data for jumping mechanography in Canadian children, adolescents and young adults

OBJECTIVES To provide age- and sex-specific reference data for mechanography-derived parameters of muscle function in Canadian children and youth using the single two-legged jump (S2LJ) with hands-on-waist. METHODS Our sample included 2017 observations from 715 participants (9-21 years; 338 girls). Participants performed three S2LJ with hands-on-waist on a force platform (Leonardo Mechanograph, Novotec). Outcomes were maximum peak power (Pmax), Pmax/mass, peak force/body weight (Fmax/BW), force efficiency, maximum jump height (Hmax), and velocity (Vmax). We used the LMS method to construct age- and sex-specific percentile curves and mixed effects models to examine sex and ethnic differences. RESULTS With the exception of Efficiency, mechanography outcomes were greater in girls (4-40%, p<0.05) than boys at age 9. Boys' advantage in mechanography parameters emerged in adolescence (age 11-13 years; 3-65%, p<0.05) and persisted into young adulthood, except for Fmax/BW which was not greater in boys until age 17 (4-10%, p<0.05). Mechanography outcomes were 3-9% (p<0.05) greater in Asian compared with white participants. CONCLUSIONS We provide the first reference data for the S2LJ using the hands-on-waist protocol in children, youth and young adults. These data support previous findings using freely moving arms and can be used when evaluating muscle function in pediatric studies.