Letter: Even with less muscle we are endurance champs

From Malcolm Knight, Rheda Park, Cumbria, UK

Colin Barras reports a study suggesting primates, which includes us, sacrificed slow-twitch muscle to provide energy for bigger brains (10 March, p 10).

However, this clashes with the idea that early humans were nomadic hunter-gatherers, a way of life for which slow-twitch muscle is essential. With the advent of farming, humans would again rely on slow-twitch muscle when spending all day in the fields tending livestock or ploughing, sowing and so on.

As a personal trainer, I know that humans have an outstanding capacity for endurance. What we lack is the strength and explosive power that results from fast-twitch muscle.