A multi-level analysis of individual- and school-level correlates of physical fitness in children

Children's physical fitness is potentially influenced by biological, behavioural and environmental factors.To investigate the importance of individual-level and school-level characteristics in explaining variation in children's physical fitness.The sample comprised 354 Portuguese children, aged 5-10 years. Physical fitness [(handgrip (HG) strength, standing long jump (SLJ), shuttle-run (SR), total physical fitness score (PFz)], gross motor coordination (GMC) and body mass index (BMI) were assessed. Moderate-to-vigorous physical activity (MVPA) was objectively monitored; birth weight and socio-economic status (SES) were obtained by questionnaire. School contexts were assessed via an objective audit. Multilevel models using the Bayesian approach were used.Age was positively associated with HG, SLJ and PFz (p < 0.05); BMI was positively associated with HG (p < 0.05) and GMC with all physical fitness components (p < 0.05); MVPA was only associated with PFz (p < 0.05); children with level A SES outperformed those with level C SES in HG (p < 0.05), but those with level B SES outperformed their level A SES peers in SR (p < 0.05). Within the school context, no equipment for physical education was negatively associated with HG (p < 0.05).In the primary school years, individual-level characteristics were more important than the school context in explaining variations in physical fitness.