Caffeine may significantly improve athletic performance, according to a study which found that caffeine supplementation reduced sprint time in the 100-metre dash.

Caffeine, a stimulant that affects the nervous system, is a popular choice among athletes as a performance-enhancing aid.

The World Athletics, formerly known as the International Association of Athletics Federations, has recognised caffeine as an "ergogenic aid" in a consensus statement on nutritional strategy for athletics, the researchers said.

"While previous studies have investigated the effects of caffeine on running activity, evidence from these studies is not conclusive enough to support the World Athletics consensus," said Professor Takeshi Hashimoto from Ritsumeikan University in Japan.

"A majority of them have looked at its effects on single sprint runs of less than 60 metres. Therefore, it was important to study the ergogenic effects of caffeine on the 100-metre sprint performance," Hashimoto said.

The study, published in the journal Medicine & Science in Sports & Exercise, recruited 13 male collegiate sprinters.

In a preliminary test, the researchers determined the time it takes for each athlete to reach peak blood plasma caffeine concentration after ingesting it.

Taking this into account, the athletes were called two more times for 100-metre time trials after ingesting either caffeine or placebo supplements. As measures of performance, the researchers measured the sprint velocity and calculated the sprint time.

On discounting the effects of environmental factors, the corrected sprint time was used to examine the effects of caffeine supplementation.

The study showed that the corrected 100-m sprint time was shortened significantly for athletes who received caffeine, with a decrease of 0.14 seconds compared to the controls.

This decrease in the time was largely associated with a decrease in sprint time for the first 60 metres of the sprint, the researchers said.

They also found that the mean sprint velocity for the 0–10 m and 10–20 m splits was significantly higher in the athletes who received caffeine.

No significant difference was seen in the sprint time for the last 40 metres of the sprint, despite the shortening of the sprint time in the first 60 metres, according to the researchers.

These observations suggest that the caffeine supplementation provided more explosive acceleration to the sprinters in the early stage of the race, they said.

These results could translate to the enhancement of sports performance for athletes by enhancing the usage of caffeine as an ergogenic aid during sprints, the researchers added.