How did you carry a load when you grew up? When I was young we carried loads – school books, grocery sacks, etc – in our arms so that our shoulders were rounded forward. Babies, too, carried in the arms. Result: rounded shoulders and backs.
Not so in Africa, where in most areas loads are carried on the head and babies are strapped to the back. This much more evenly spreads weight and transfers it from shoulders and muscles to the whole vertical skeleton.
As Blaine Harden says,
[The woman he is talking about] walked five miles with the fifty-pound load on her head. Researchers in biomechanics have found that African women can carry up to 20 percent of their body weight on their heads while burning no more energy than if they were carrying nothing at all.Physiologists speculate that women, who start carrying heavy loads at about age twelve, have learned how to walk with extraordinary smoothness, with no back-and-forth oscillation. They also suspect the women have adapted their spines to carry loads with bones rather than muscles.When Western women or men attempt to carry such weight, researchers, found, they hurt their necks…
– Blane Harden – Africa: Dispatches from a Fragile Continent
There is much to be learned here. Rarely are Africans in rural areas plagued with ‘bad backs’, nor have I seen cases of disfiguration of shoulders, etc, from a lack of calcium. And for sure, many rural diets of females are probably lacking in calcium.
By contrast, western women and men do suffer from these problems. For babies, the solution is to buy strollers, thus separating the infant from its mother as well as removing its weight from the mother.
Back packs have become quite popular over the last decade in the West. Will that make any difference? Perhaps over the next years we will see.