Longer breastfeeding is associated with increased lower body explosive strength during adolescence

Our aim in this study was to examine the association between breastfeeding duration and cardiorespiratory fitness, isometric strength, and explosive strength during adolescence. A total of 2567 adolescents (1426 girls) from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) cross-sectional study aged 12.5-17.5 y were included. Information about duration of any and exclusive breastfeeding was obtained retrospectively by means of a parental questionnaire. The 20-m shuttle run, handgrip strength, and standing long jump tests were used to assess physical fitness. Significant differences among the categories of breastfeeding duration were tested using ANCOVA after adjusting for a set of potential confounders: gestational and current age, birth weight, sexual maturation, fat mass, fat-free mass, maternal education, parental weight status, country, smoking behavior, and days of vigorous physical activity. Longer breastfeeding (either any or exclusive) was associated with a higher performance in the standing long jump test in both boys and girls (P < 0.001), regardless of fat mass, fat-free mass, and the rest of potential confounders. In adolescents who were breastfed for 3-5 mo or ≥6 mo, the risk of having a standing long jump performance below the 5th percentile was reduced by half compared with those who were never breastfed [odds ratio (OR) = 0.54, 95% CI = 0.30-0.96, P < 0.05; and OR = 0.40, 95% CI = 0.22-0.74, P < 0.01, respectively). These findings suggest a role of breastfeeding in determining lower body explosive strength during adolescence.