Physical fitness and associations with anthropometric measurements in 7 to 15-year-old school children

Objective: To analyze associations between health-related physical fitness and the anthropometric and demographic indicators of children from three elementary schools in Botucatu, SP, Brazil. Methods: The sample for this cross-sectional study was composed of 988 students, recruited from the second to ninth grades (an age range of 7 to 15 years). The children underwent anthropometric assessment (weight, height, waist circumference and tricipital and subscapular skin folds) and were tested for health-related physical fitness (flexibility: sit and reach test; abdominal strength/resistance: 1-minute abdominal test; and aerobic resistance: 9-minute running/walking test). Data were analyzed using descriptive statistics plus Student's t test, the chi-square test or Fisher's exact test and logistic regression with a significance level of 5%. Results: The physical fitness levels observed were significantly influenced by age (all levels), sex (abdominal strength/resistance), obesity (all levels), body adiposity (flexibility, abdominal strength/resistance) and abdominal adiposity (abdominal strength/resistance and aerobic resistance). Females were more prone to be unfit in abdominal strength/resistance. Both obesity and excessive abdominal adiposity predisposed children to be unfit in abdominal strength/resistance and aerobic resistance. Excess body adiposity increased the likelihood of poor trunk flexibility. Conclusions: Unhealthy physical fitness levels were related to female sex, obesity and excessive abdominal adiposity. Implementing programs designed to effect lifestyle changes to achieve physical fitness and healthy nutrition in these schools would meet the objectives of promoting healthy body weight and increased physical fitness among these schoolchildren.