This review builds on earlier reviews and considers the development of strength characteristics from childhood through adulthood. Since strength is associated with size and biological maturation, these associations are also discussed. Finally, genetic determinants of strength and tracking of strength components over time are also reviewed.
Gaston Beunen and Martine Thomis
André F. Seabra, Denisa M. Mendonça, Martine A. Thomis, Robert M. Malina and José A. Maia
The present study considered age- and sex-associated variation in sports participation (SP) in Portuguese youth.
A national survey of 12,568 students, ages 10 to 18 y, was conducted. Two items of the Baecke et al. (1982) questionnaire that deal with SP were considered. Logistic regression and factorial ANOVA were used.
The prevalence of SP is greater in males than females. Mean sport scores increased in both sexes from ages 10 to 18 y. Soccer was the most practiced sport among males, while swimming and soccer were the most practiced sports among females. Males participated in SP >5 hours per week compared to 1 to 2 hours per week in females. High-intensity sports were more prevalent among males, while sports of mid-level intensity were more prevalent among females. The majority of youth participate in sport more than 9 months of the year.
SP is an important component of physical activity among Portuguese youth and has a relatively stable prevalence between ages 10 to 18 y.
Gaston Beunen, Martine Thomis, Maarten Peeters, Hermine H. Maes, Albrecht L. Claessens and Robert Vlietinck
The aim of this study is to quantify the genetic and environmental variation in isometric and explosive strength (power) in children and adolescents, using structural equation models. Arm pull (static strength) and vertical jump (explosive strength, power) were measured in 105 twin pairs from the Leuven Longitudinal Twin Study. Boys and girls were tested at annual intervals between 10 and 16 years and at 18 years. Path models were fitted to the observed strength characteristics and a gender heterogeneity analysis was performed at each age level. A model including additive genetic and specific environmental factors (AE-model) allowing for a difference in total phenotypic variance or in genetic/environmental variance components in boys and girls best explains both strength characteristics at most age levels. The additive genetic contribution for isometric strength varies between a2 = .44 and a2 = .83, and for explosive strength between a2 = .47 and a2 = .92, except at 16 years in males. In conclusion there is good evidence that during the growth period both static and explosive strength are under moderate to moderately strong genetic influence.