My guess would be a sports mad country like Australia. Children participate in physical activity from primary school, and it is compulsory throughout high school as well. The schooling system is from a preparatory year to grade 7 (8 yrs) for primary, and grade 8-12 (5 yrs) for secondary. That's a total of 13 years that the child will have physical education as part of their curriculum, plus many schools offer Friday afternoon activities as well as participation in school sporting teams on weekends. I don't know how other countries compare to this, but I would rate the involvement of sports in the Australian education and culture very highly (perhaps too highly sometimes). This is interesting despite the trend of childhood obesity also catching on in Australia