In adult life, the effect of regular physical activity in promoting aerobic fitness, increasing muscular strength, lowering blood lipids, reducing high blood pressure, countering obesity, retarding osteoporosis, improving blood glucose control, and increasing psychological well-being is extensively documented[I]. Evidence is accumulating to support the view that adults' health and well-being has its origin in behaviour established during childhood[2] and there is general agreement that young people should be encouraged to adopt active lifestyles[3]. However, relatively little is known about young children's physical activity patterns.