Purpose: To determine the 12-month maintenance of a 9-month, thrice-weekly, 10-minute high-intensity exercise program, delivered in schools, on bone and other health-related performance variables in prepubertal children.
Methods: All participants (N = 311) of the CAPO kids trial (testing times T1-T2) were contacted to undergo retesting (T3) of all original measures-including weight, standing and sitting height, calcaneal broadband ultrasound attenuation (Achilles, GE), and stiffness index (Achilles, GE)-waist circumference, resting heart rate, blood pressure, vertical jump, and aerobic capacity. Maturity was determined by estimating age of peak height velocity using sex-specific regression equations.
Results: A total of 240 children [12.3 (0.6) y old] were included in the current study (77% of initial follow-up sample at T2). Between the T2 and T3 time points, both exercise (EX) group and control (CON) group increased broadband ultrasound attenuation (EX: 5.6%, P ≤ .001; CON: 6.5%, P ≤ .001), stiffness index (EX: 7.3%, P ≤ .001; CON: 5.2%, P ≤ .001), vertical jump (EX: 5.9%, P ≤ .001; CON: 6.3%, P ≤ .001), estimated maximal oxygen consumption (EX: 13.3%, P ≤ .001; CON: 12.1%, P ≤ .001), and reduced waist circumference (EX: -5.2%, P ≤ .001; CON: -5.6%, P ≤ .001), with no between-group differences in the magnitude of those changes. No differences were detected in absolute values between groups at T3.
Conclusion: Although the statistically significant differences observed between groups following the intervention were no longer significant 1 year after withdrawal of the intervention, the between-group similarities in growth trajectories of those parameters could suggest that some benefit of the intervention for bone health, waist circumference, and physical performance endured.
Keywords: exercise; lean mass; obesity; pediatric; physical activity.