Do extra compulsory physical education lessons mean more physically active children – findings from the childhood health, activity, and motor performance school study Denmark (The CHAMPS-study DK)

Niels Møller, Jakob Tarp, Eva Kamelarczyk, Jan Brønd, Heidi Klakk, Niels Wedderkopp
International Journal of Behavioral Nutrition and Physical Activity 2014, 11:121 (24 September 2014)