How Do Humans Compare With Other Animals?

Loughborough University Physiologist, Rona Pierce says training is the main reason for efficient running. But there may be other factors too, as she explained to BBC World Services, crowd science. Age probably comes into it in that there's probably an optimal age for tender knee elasticity. That tends to drop off as you get older, so probably there's a sweet spot in age for running economy. So, in terms of weight, it depends what your weight is made up of. If you've got more muscle mass, that's going to help you, whereas if it's more fat, then you've got to carry it.