A mathematical analysis of Olympic champion Usain Bolt's famous Berlin run reveals new insights about the athlete is so quick on his feet by accurately modeling the runner's world record-setting 100 meter dash in 2009.
The researcher's model indicated that Bolt's 9.58-second 100 meter dash -- which is still a world record -- was achieved by reaching a terminal velocity of 12.2 meters per second (27 mph) and exerting an average force of 814.8 newtons.
Bolt produced a remarkable 81.58 kilo Joules of energy during the sprint. In other words, he generated 50 times more energy than a speeding bullet. When a 0.44 caliber Magnum handgun bullet leaves the chamber it produces just 1.6kJ of energy, according to The Daily Mail.
Unlike bullets, which are tiny and aerodynamic and capable of reaching speeds of 1,000 mph, Bolt's physique is more cumbersome. His 6 foot 5 inch frame catches more drag than most of the people he's racing; more than 92 percent of Bolt's energy was absorbed in battling air resistance, meaning he used just under eight percent of the energy to achieve motion.
"Our calculated drag coefficient highlights the outstanding ability of Bolt," said study co-author, Jorge Hernandez. "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."
Hernandez, who works out of the National Autonomous University of Mexico, continued:
"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.
"This is all because of the 'physical barrier' imposed by the conditions on Earth. Of course, if Bolt were to run on a planet with a much less dense atmosphere, he could achieve records of fantastic proportions."
Hernandez and his colleagues stated that race officials might also be interested in their calculations because the equations used also account for the effect of tailwind, which can vary between races and also significantly reduce running times.
John Barrow at Cambridge University who has previously analyzed how Bolt could become even faster, told the BBC that a tailwind of no more than 2 meters per second is allowed for a record to count.
"So without becoming any faster he has huge scope to improve," Barrow said.
"The accurate recording of Bolt's position and speed during the race provided a splendid opportunity for us to study the effects of drag on a sprinter. If more data become available in the future, it would be interesting to see what distinguishes one athlete from another," Hernandez said.
Hernandez and his colleagues' research is published in the European Journal of Physics.