I've recently published an article in the academic journal Sport in Society on the question of the contribution sport and other forms of physical activities might make to school grades and examinations. This is the abstract / summary:
Sport and other forms of physical activities have traditionally held an ambiguous place within schooling, often being pushed to the margins. At the same time, there is a consensus that such activities are necessary for the healthy development of young people. This was proven during the second half of the last century, representing a revolution in the understanding of health. Recent developments in neurology, psychology and related sciences hint at a second revolution in which a strict distinction between mind and body has physical activity can make distinctive contributions to educational achievement, and a host of wider benefits. Focusing on cognitive functioning, psychosocial development, school engagement and general educational attainment, the article reviews the available evidence and concludes that there is sufficient reason to believe that sports and physical activity can make useful contributions to educational achievement.
The article can be accessed here. Unfortunately, it is currently protected by a pay-wall. However, I will put a pre-publication version on ResearchGate and Academia.edu, which will be freely available.