A 3-year school-based exercise intervention improves muscle strength - a prospective controlled population-based study in 223 children.

Background: Intense physical activity (PA) improves muscle strength in children, but it remains uncertain whether moderately intense PA in a population-based cohort of children confers these benefits.

Methods: We included children aged 6-9 years in four schools where the intervention school increased the school curriculum of PA from 60 minutes/week to 40 minutes/school day while the control schools continued with 60 minutes/week for three years. We measured muscle strength, as isokinetic Peak Torque (PT) (Nm) of the knee flexors in the right leg at speeds of 60°/second and 180°/second, at baseline and at follow-up, in 47 girls and 76 boys in the intervention group and 46 girls and 54 boys in the control group and then calculated annual changes in muscle strength.

A 6-year exercise program improves skeletal traits without affecting fracture risk: a prospective controlled study in 2621 children.

Most pediatric exercise intervention studies that evaluate the effect on skeletal traits include volunteers and follow bone mass for less than 3 years. We present a population-based 6-year controlled exercise intervention study in children with bone structure and incident fractures as endpoints. Fractures were registered in 417 girls and 500 boys in the intervention group (3969 person-years) and 835 girls and 869 boys in the control group (8245 person-years), all aged 6 to 9 years at study start, during the 6-year study period.

A 5-year exercise program in pre- and peripubertal children improves bone mass and bone size without affecting fracture risk.

We studied the effect in children of an exercise intervention program on fracture rates and skeletal traits. Fractures were registered for 5 years in a population-based prospective controlled exercise intervention study that included children aged 6-9 years at study start, 446 boys and 362 girls in the intervention group and 807 boys and 780 girls in the control group. Intervention subjects received 40 min/school day of physical education and controls, 60 min/week.

Influence of a 3-year exercise intervention program on fracture risk, bone mass, and bone size in prepubertal children.

Published prospective pediatric exercise intervention studies are short term and use skeletal traits as surrogate endpoints for fractures, whereas other reports infer exercise to be associated with more trauma and fractures. This prospective, controlled exercise intervention study therefore followed both skeletal traits and fracture risk for 36 months. Fractures were registered in children aged 7 to 9 years; there were 446 boys and 362 girls in the intervention group (2129 person-years) and 807 boys and 780 girls in the control group (4430 person-years).