Abstract

Background: The high prevalence of overweight and obesity among Chilean schoolchildren represents a significant public health challenge, impacting their physical performance and overall well-being. Objective: To analyze the relationship between body weight and physical capacities in schoolchildren aged 6 to 12 years from highly vulnerable public schools in Santiago, Chile. Methods: A cross-sectional observational study was conducted with 154 students from three public schools, assessing nutritional status, physical fitness (handgrip strength, standing long jump, 4x10m shuttle run test), and motor capacity. Correlations were analyzed using Spearman's coefficient. Results: A prevalence of overweight and obesity of 42.8% was found. Children with obesity had significantly lower performance in the standing long jump compared to normal weight peers (p = 0.016). Handgrip strength showed moderate correlations with weight and height but low functional relevance. The standing long jump test demonstrated a moderate correlation with handgrip strength and agility, supporting its value as a screening tool for motor function. Conclusions: Excess weight negatively impacts functional strength in schoolchildren, particularly in explosive tasks such as the standing long jump. Despite the absence of differences in overall motor capacity across BMI groups, the low general motor capacity observed highlights the need for school-based programs promoting motor skill development and physical activity. Play-based and high-intensity strength training activities in schools represent a feasible strategy to enhance children's physical health and quality of life.