Determinants of mechanical efficiency trajectories from childhood to adolescence: Findings from the QUALITY cohort

To estimate the shape and number of mechanical efficiency (ME) trajectories from childhood to adolescence; and verify whether ME trajectory membership can be predicted by sex, biological maturation, body weight, body composition and physical activity (PA) in childhood.Data from QUALITY, an ongoing cohort study on the natural history of obesity, were used. Participants attended a baseline visit (8-10 years, n = 630) and follow-up visits two years (n = 564), and seven years (n = 377) later. ME was assessed by an incremental cycling test at 50w (MEMean age of the 454 participants (boys = 54%) was 9.7 ± 0.9 years at baseline. Two distinct MEWe found evidence that excess weight at baseline predicts low levels of ME in childhood and adolescence. Additionally, higher PA at baseline is not related to higher ME