Catch me if you can

With superhuman Jamaican sprinter Usain Bolt holding sway, are there ANY limits to what the human body can achieve?

It was not that long ago that the 10-second barrier was thought to be unbreakable; now people are starting to ask if anyone could run 100 metres in nine seconds? Or even less?

Put bluntly, no human is ever going to run 100m in five seconds, or a marathon in 90 minutes - not without some serious genetic or prosthetic modification.

The top speed of an elite human male sprinter is a shade under 30mph, and the limits of our skeletal and musculature systems probably mean that 40mph is unlikely to be achieved.

Such feats are (probably) beyond what the human body can do - but that still leaves some way for the records to fall.

So how incredible is Usian Bolt's 100 metres achievement? One way of looking at it is to consider how long it normally takes to knock a tenth of a second off the 100m record.

On Oct 14, 1968, Jim Hines ran 9.95sec in the Mexico City Olympics (the first sub-10-second time).

From that day on, it took 28 years for this record to come down by the same amount that Bolt has now cut his own world record.

In fact, the story of the past 33 (when electronic timers meant hundredth-second increments could be measured) is of sprint records falling by 0.01 or 0.02 and never, up to now, more than 0.05 seconds at a time.

So Bolt's leap is truly extraordinary.

As is the performance of modern sprinters in general. In the 40s, 10.2 seconds was a world-class 100m time - nowadays this wouldn't get you into a major athletics final.

There are several reasons why athletes get faster and stronger.

First, equipment. The shoes worn by today's sprinters, for example, are custom-made, featherweight,
computer-designed marvels, a world away from the crude spiked shoes worn by top athletes a generation ago.

Running tracks are grippier and unyielding, meaning that less energy is wasted. Such things make little difference over the longer distances, but have a disproportionate effect in the sprints.

On the human side, it is training which has undoubtedly accounted for much of the improvements in sports as disparate as track athletics, swimming and tennis.

In the 60s, training was a relatively ad hoc, amateurish affair compared to the professional, scientific precision of today.

Bolt, a determined and intelligent professional, will monitor - and have monitored - every single aspect of his physiology and diet.

Training runs and weights sessions are being formulated using the latest advances in sports medicine.