Porters plod – no fancy tricks
Nepalese porters' superhuman load-bearing marathons are powered by extreme exertion alone.
Nepalese porters can trudge up the highest mountains in the world with packs weighing more than their own body weight. But they don't have any special secrets – they move slowly and take frequent rests.
Norman Heglund from the Catholic University of Leuven in Belgium and colleagues found Kikuyu and Luo women in Kenya carry water on their heads conserve up to 80% of the energy from the previous step, enabling them to carry loads of up to 20% of their body weight with no additional effort.
But porters in Nepal don't have any tricks. Heglund found they move at a relatively slow speed of around three to four kilometres an hour and took frequent breaks, walking sometimes for as little as 15 seconds before resting for another 45 seconds.
The fact that their steps are never on the same level prevents them from moving economically, Heglund says, making it "all the more awe-inspiring that they carry these heavy loads up and down hills at high altitude as they do it the hard way".
The work was published in the Journal of Experimental Biology.