A most recent novel study was performed with German primary school children.  Researchers wanted to determine whether giving the children rolling luggage, to carry their school books, might reduce spinal stress. As it turns out, what might work well at the airport does not work so well for children, lugging his books across uneven sidewalks, all the way to school. The authors had to conclude that: “This suggests that school children should use backpacks rather than trolleys when the weight is within recommended limits”.