What makes Usain Bolt so fast.

Usain Bolt is the world's fastest man. But what makes him so fast? Scientists have said that they can explain Bolt's extraordinary speed through the use of a mathematical model.

Usain Bolt runs fast. Very fast. His 100 meters time of 9.58 seconds during the 2009 World Championships in Berlin is the current world record. How come Bolt is so much faster than other athletes? Mexican scientists have put together a model to explain why. The model has been presented in the European Journal of Physics.

According to the Daily News, the researchers say that their model explains the power and energy he had to expend to overcome drag caused by air resistance, made stronger by his frame of 6ft 5in. The model begins by analyzing the record Berlin run. The model explains that Bolt's time of 9.58 seconds in Berlin was achieved by reaching a speed of 12.2 metres per second, equivalent to about 27 miles per hour.

From this, the scientists explained that: Bolt's maximum power occurred when he was less than one second into the race and was only at half his maximum speed (Bolt had a maximum power of 2619.5 watts after only 0.89 seconds of the race). This demonstrates the near immediate effect of drag, which is where air resistance slows moving objects.

The researchers also discovered less than 8% of the energy his muscles produced was used for motion, with the rest absorbed by drag. When comparing Bolt's body mass, the altitude of the track and the air temperature, they found out that his drag coefficient - which is a measure of the drag per unit area of mass - was actually less aerodynamic than that of the average person.

Jorge Hernandez, co-author of the study told the Daily Mail that: "Our calculated drag coefficient highlights the outstanding ability of Bolt. He has been able to break several records despite not being as aerodynamic as a human can be. The enormous amount of work that Bolt developed in 2009, and the amount that was absorbed by drag, is truly extraordinary.

It is so hard to break records nowadays, even by hundredths of a second, as the runners must act very powerfully against a tremendous force which increases massively with each bit of additional speed they are able to develop."

The full stats relating to Bolt's record run are:

Height: 6 ft 5 in.

Distance: 100m

Time: 9.58 seconds

Terminal Velocity: 12.2 m/s (27.3 mph)

Average Force: 815.8 newtons

Tailwind: 0.9 m/s (~2 mph)