Everyone knows heavy school bags pose a serious threat to the health and well being of children. In light of this, researchers have found that trolley bags are better than backpacks for school kids for their movement and body posture. They also suggest that children should not carry over 20% of their body weight in their backpack trolleys as it hampers their movement. For the study published in the journal Applied Ergonomics, researchers from the University of Granada and Liverpool John Moores University assessed 49 primary school pupils from Spain. In Spain, more than 40% of the children use trolley backpacks and until now there have been no studies making weight recommendations for this type of backpack, added researchers.
For the study, a kinematic analysis of the children keeping in mind the posture of the trunk and lower limbs was conducted while they walked freely – carrying no weight, carrying a traditional backpack and while pulling a backpack trolley with different loads (10%, 15% and 20% of their respective body weights).
It was found that pulling the backpack trolley produces fewer changes in the child's kinematics and, therefore, resembles more closely their movement when walking free of any load, compared to carrying backpacks, even when it weighs very little. The study also revealed that the greatest alterations were produced in the hip and trunk when using trolleys or backpacks while there was little difference in the kinematics of the knee and ankle. On a whole, the study concludes that schoolchildren who use backpacks should avoid carrying loads greater than 10% of their body weight. On the other hand, when pulling a school backpack trolley, the child should avoid carrying any load greater than 20% of their body weight. Parents, take note! Educate your kids and keep them away from back and knee problems from such an early age.