Jones has identified nitrates as a key ingredient in performance. Sources of nitrates include leafy green vegetables as well as beetroot juice.
Genetics also helps.
So what is it about their physiology that has allowed African runners to dominate distance running so comprehensively in recent years? “Their body types tend to be smaller and naturally leaner,” Jones said. “Their limbs have slightly different proportions, which make them run more efficiently. They have slightly longer shanks; their lower legs tend to be relatively long compared to their thighs, they don’t tend to carry a lot of muscle on their calves and they have quite long achilles, which can be quite advantageous. Their V02 Max [maximum oxygen uptake] may not be much higher than what you’d find in a good class of distance runner in the UK, but they’re much more economical and they’re able to operate at high fractions of their max almost without fatigue.”