By contrast, the vast majority of unshod runners don’t hit the ground with their heels, landing instead on the sides or balls of their feet, the study found.
The practice is especially common in several east African countries where long-distance running is nearly a national past time.
But even well-cushioned sports shoes that help distribute weight across the foot cannot fully absorb the shock of these blows: 30 to 75 per cent of regular runners each year suffer repetitive stress injuries.
But up to now, there has been little scientific evidence supporting the claim that barefoot is better.
A radical reshaping of the foot about two million years ago, including shorter toes and a fully-arched foot, probably occurred to enhance our ability to move quickly over sustained periods.