The following websites will give you a better insight about the trauma of heavy schoolbags that is
an unexplained and unjustified phenomenon.
http://www.nhs.uk/news/2012/03march/Pages/rucksack-bags-back-pain-children.aspx
http://health.india.com/diseases-conditions/the-ill-effects-of-carrying-heavy-schoolbags/
http://www.dailymail.co.uk/news/article-2114118/Heavy-school-bags-deforming-children-growing-numbers-suffer-irreversible-problems.html
http://www.bbc.co.uk/news/health-17365880