Timings for the women’s 100 metres approached a plateau in 1977. Male sprinters are still improving, but having constructed a model based on other events, Denny says they too seem on the verge of topping out. He predicts an absolute limit of 9.48 seconds for the 100 metres, just 0.1 seconds under Bolt’s current record. “If he keeps on course he will soon come close to the absolute limit,” says Denny.
What gives rise to this human speed limit? Denny reckons it’s as simple as the athlete’s power-to-weight ratio. Beyond a certain point, the benefits of stronger muscles and longer limbs will be offset by the increased energy required to shift the greater load.