The question:

What is the effect of the level of physical activity and movement education on the short and long-term skeletal development and health of our children?

Osteoporosis is a major public health problem for both men and women because of the morbidity and mortality associated with fragility fractures. Although a disease of the elderly there is now increasing evidence that adulthood osteoporosis is strongly related to skeletal development during childhood and adolescence. For instance, a 10% increase in peak bone mass is estimated to delay the development of osteoporosis by 13 years. Thus the prevention of osteoporosis also has its origins in childhood; that is, increasing peak bone strength during growth is a key prevention strategy for reducing the long-term risk of osteoporosis and fracture.

The paucity of longitudinal interventional studies addressing the effects of exercise and diet on musculoskeletal health in children and adolescents limits our understanding of the risks of compromised bone health in normally active healthy children. Our project therefore offers a unique opportunity for advancing the understanding of skeletal growth and adaptation to exercise in children and to specifically track the effects of a school based physical education intervention in a non-clinical group of children at the greatest risk of suboptimal musculoskeletal health.

Bone density and body composition will be determined by dual energy x-ray absorptiometry (DXA). Peripheral quantitative computed tomography (pQCT) will be used to assess bone geometry and density at the tibia and radius. These procedures are well documented to produce valid and reliable measures in children and adults.