Wednesday, August 18, 2010

The 'Science' of Carrying Loads on Your Head

Carrying relatively heavy loads for long distances is still a regular activity for many people in the developing world, especially in Angola. For a variety of reasons (cultural, economic and practical), Angolan women regularly employ some form of head-load carriage, most often to transport essential items such as water and firewood.

Interestingly, within the Angolan cultural norms, only women are seen carrying items on their heads, while men usually carry loads on their shoulders. As one can imagine, head-supported loads are inheritantly unstable and they need well-developed neck muscles to support the spinal loading.
To be able to carry loads on their head, Angolan children start developing the balance and musculature in their early teens carrying bricks or small buckets of water and progress to heavier loads as they get older.

Scientific research in the UK and South Africa shows that African women can carry up to 20% of their
bodyweight with no additional energy exertion on level ground and that any load above 20% of their body weight incurs a proportional energy cost. For example, carrying 30% of BM (body mass) requires a 10% increase in energy - the 'free ride' hypothesis. With heavier loads, the energy increase was only half that of men carrying the same loads on their backs.

At any rate, with the prevelence of Angolan women carrying loads on their heads, it is easy to see that they are truly a labour force in the country.

The pictures in this posting are thanks to Kevin and Angela, Canadian missionaries serving at the CEML Hospital.

1 comment:

Madama said...

Wonderful Blog. It was really interesting to go through your blog about Angola! Keep blogging...