World's fastest man Usain Bolt believes he is capable of lowering sprinting's most impressive ever marks over both the 100m and 200m distances, but in a race against the clock the sprint king could already be falling behind.

At his brilliant best for the past seven years, it has often seemed that Bolt, once fully fit, has seen his biggest competition come from the clock, but father time may be catching up. At 27-years old, Bolt is already above the average age of 24.6 that has seen most sprinters in the last 50 years challenge the world's best mark.

Oldest of the sprinters

In fact, of the 14 athletes that have broken the 100m record during that period, only four have managed to do so above the age of 26. The oldest of the sprinters was Carl Lewis, joined in the category by Leroy Burrell and Maurice Green, who set a new mark for sprinting's blue ribband event at the age of 30 in 1991. With less athletes having challenged the mark over the 200m event since 1968, the prospect is a little better for the sprint star, with only himself and the United States Tommie Smith have broken the mark below the age of 26. The previous record holder Michael Johnson was already 29-years old when he set what seemed an immovable mark in 1996.

But all is not lost. Few can argue, however, that the sprinter is above all else extraordinary and with various factors in his favour, the marks could yet fall. He was the second slowest of all the finalists to react in Beijing and third slowest in Berlin when he ran 9.58. In Beijing Bolt's reaction time was 0.165 s for his 9.69 run, the other seven finalists reacted in 0.133, 0.134, 0.142, 0.145, 0.147, 0.165 and 0.169 s. Bolt's weakest point is a very slow reaction to the gun. If he could get his reaction time down to 0.13, good but not exceptional, then he would reduce his 9.58 record-run to 9.56. Down to an exceptional 0.12 he is looking at 9.55 and all of that without improving his average speed. Another consideration is of course wind speed, with which he has not yet had the best of.

Berlin

In Berlin, his 9.58 was run in a modest 0.9 m/s tailwind and in Beijing there was none. A 2 m/s tailwind is worth about 0.11s compared to a no-wind performance, and a 0.9 m/s tailwind 0.06 s, at a low-altitude site. With the best possible legal wind assistance and reaction time, Bolt's Berlin time is down from 9.53 s to 9.47s.