HUMAN ancestors living 3 or 4 million years ago may not have walked with a stooped, ape-like posture after all.
Weijie Wang and a team from the University of Liverpool in the UK asked volunteers to walk normally, fast, slowly or with a stooped posture, and analysed how much energy they used in each gait. They found that when people are walking comfortably, their body鈥檚 potential energy is easily converted to kinetic energy, and vice versa. But a stooped posture is so inefficient that they doubt it would have evolved in the first place (Journal of Human Evolution, vol 44, p 563). One way it might have happened, they say, is if stooping confers some unknown benefit. Alternatively, the different anatomical structure of primitive humans may have favoured a stooped posture.