By contributor Sean Carey
In many rural and urban areas in countries in Africa, the Indian subcontinent, Latin America and elsewhere, loads are routinely carried on the head. If a young person has learned the technique well from their elders and is well-practiced, head porterage is a very efficient method of transportation.
Research carried out over a quarter of a century ago at the Catholic University of Louvain found that Luo and Kikuyu women of East Africa were able to carry loads of 20 per cent of their body weight without increasing their energy consumption. For heavier loads, there was an increase in the amount of energy used: a 30 per cent load increased energy consumption by 10 per cent, while a 40 per cent load caused an increase in energy consumption of 20 per cent. Additionally, they were far more efficient than army recruits carrying equivalent loads in backpacks.
More recent research published in 2005 by the same team, investigating the Sherpas of Nepal, found that men typically carry 50 kg loads and women 40 kg loads. In an emergency, they carry 80 kg and 60 kg respectively over relatively short distances, which is more than their own body weight. Female Sherpa porters were more efficient by a metabolic cost of around 25 per cent at carrying loads than the sample of East African women studied a quarter of a century earlier.
Nevertheless, not all of those accustomed to head-load carrying can perform it efficiently. Research in Ghana in the early 1990s found that among some 305 head porters (164 males and 141 females) cervical spondylosis was not exclusively a function of age, but a consequence of heavy load carrying on the head. More recent research carried out on 24 Xhosa women, in South Africa, by researchers from the University of Abertay Dundee called into question whether head porterage is more efficient than carrying loads in a backpack.
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