Are children and adolescents with ADHD less physically fit? Findings from a systematic review and meta-analysis

BACKGROUND: Health-related physical fitness is critical from early childhood, yet it is unclear whether children and adolescents with attention-deficit/hyperactivity disorder (ADHD) differ from their typically developing (TD) peers. OBJECTIVE: To systematically review and meta-analyze differences in health-related physical fitness between children and adolescents with and without ADHD. METHODS: and Setting: Seven electronic databases were searched for studies comparing cardiorespiratory fitness, muscular strength, and flexibility between children and adolescents with ADHD and TD peers. Methodological quality was evaluated using the Mixed Methods Appraisal Tool. RESULTS: Thirteen studies including 1,814 participants (560 with ADHD, 1,254 typically developing [TD]) were reviewed. Eleven studies assessed cardiorespiratory fitness. Pooled data from two VO₂peak studies (28 ADHD, 33 TD) showed no significant group differences (mean difference = -4.28 mL·kg⁻¹·min⁻¹; 95% CI: -10.51 to 1.96; p = 0.18; I² = 59%). Seven studies using field-based tests revealed mixed outcomes. Pooled data from six studies using the 20-meter Shuttle Run or PACER test (149 ADHD, 949 TD) indicated significantly lower performance in the ADHD group (standardized mean difference = -0.46; 95% CI: -0.78 to -0.14; p = 0.004; I² = 47%). Five studies examining heart rate variables reported no significant differences (mean difference = 2.23 bpm; 95% CI: -2.72 to 7.19; p = 0.38; I² = 42%). Muscular strength outcomes (six studies) and flexibility (five studies) showed minimal differences between groups (strength: SMD = -0.07, 95% CI: -0.31 to 0.17; flexibility: SMD = -0.16, 95% CI: -0.65 to 0.33), with low-to-moderate heterogeneity. CONCLUSION: Children and adolescents with ADHD exhibit comparable levels of muscular strength and flexibility to their TD peers. Evidence on cardiorespiratory fitness is mixed and depends on assessment methods: field-based tests indicate lower performance in ADHD, while laboratory peak oxygen uptake (VO₂peak) and resting heart rate measures show no significant differences.