"This calls into question popular opinion, as well as guidelines published by numerous organisations recommending limits on backpack weights for children. Globally, there’s been little agreement on what a limit should be. Guidelines vary, with the limit being anywhere between 5% and 20% of body weight."

"Preventing mental illness is just as important as preventing other chronic conditions such as heart disease, diabetes and cancer. As with these chronic conditions, regular physical activity plays a key role."