Think of the kids in Africa who carry 10kg water bottles ten miles on their heads
This is the best method for carrying heavy weights and does not equate to our DCs carrying things in a lopsided way.
When carrying on the head, the weight is supported by the whole column of the body and the balance requires (so promotes) perfect posture too. The widespread use of carrying on the head across Africa and Asia shows that this is a proven ideal method for carriage of heavy things. It is efficient and does not produce any strains or aches (if done right). It is amazing what can be carried in this way . i remember seeing a chap in Tanzania with an armchair on his head
Maybe our DCs should learn how to do it from infancy
I do not remember ever having to carry as many things as they seem to have these days.