Peak expiratory flow, core performance and physical activity in normal-weight, overweight, and obese adolescents

The objectives of this study were to (1) compare peak expiratory flow (PEF), physical activity (PA), and core performance among normal-weight, overweight, and obese adolescents and (2) explore the relationships between PEF, physical activity, core performance, and anthropometric measurements across these groups. Ninety adolescents aged 10-13 yr were categorized based on BMI: normal weight (n = 30, 5th to < 85th percentile, BMI-Z score -2 to < 1), overweight (n = 30, 85th to < 95th percentile, BMI-Z score 1 to < 2), and obese (n = 30, > 95th percentile, BMI-Z score > 2). PEF and percent-predicted values of PEF (PEF% pred) values were calculated. Waist and neck circumferences were measured. Physical activity levels were assessed using the Physical Activity Questionnaire for Older Children (PAQ-C), from which total and subscores were derived. Core performance was evaluated through modified push-up (MPU) and sit-up tests. The PEF% pred and PAQ-C scores showed no significant differences between groups (p > 0.05). However, MPU repetition rates were significantly lower in obese adolescents compared to overweight (p = 0.019) and normal-weight peers (p < 0.001). There was a significant correlation between PEF% pred and PAQ-C total scores (p = 0.014), as well as out-of-school subscores (p = 0.039) in overweight adolescents. Similarly, PEF% pred was linked to MPU repetitions in obese adolescents (p = 0.029). Obese adolescents exhibited decreased core performance relative to their overweight and normal-weight counterparts, which correlated with the PEF% pred. Physical activity was associated with PEF% pred exclusively in overweight adolescents.