@My dear brother Timothy ...
The School of Physics at the University of South Wales says,
"Carrying a load on the head is efficient, as the weight is taken straight downwards. There is no tilting force on the spine since the center of mass lies on the spinal axis."
It must require proper padding or support.
I once had to carry a 70 pound suitcase. It was too heavy to carry on my hip or in front of me, so I tried positioning the load on my head (remembering similar photos of the technique) with my hands balancing the container at the sides.
It really was uncomfortable against the center top of my skull and walking was difficult because the load, like a top-heavy bookshelf, cantered forward and back.
I'm certain the ladies (and brick wallah in Bangladesh) grew up carrying loads like that and probably had conditioned heads as a result.
From my experience, the backpack braced against the hips makes for easiest carrying of heavy loads with the bulk of the weight supported by the legs.
Though admittedly a fellow sweats like a big. A 70-pound backpack is the thermal equivalent of a parka.*
* In the military, I had to ruck several miles under an antenna-laden back pack weighing between 70-80 pounds, heavy enough that one needed to roll into it from a seated position then tumble forward and struggle to stand up. My buddy and I also rucked heavy packs through India that were about as heavy.**
** Why do I love throwing info like that out whenever I have an audience?
