The Astonishing Physics Behind Usain Bolt's World Record Sprint
Usain Bolt's record sprint at the 2009 World Championships in Berlin left the athletic community in awe. However, the significance of his feat is not limited to the world of sports.
Even from a scientific perspective, the world record time is truly remarkable.
In a paper published in European Journal of Physics, a team of researchers explore the formal physics of what some hold to be greatest athletic performance ever recorded.
Their findings hardly undermine such praise.
Under rigorous examination, Bolt's 100 meter sprint seems even more improbable — especially given factors like air resistance and density. To cover the distance in 9.58 seconds, Bolt accelerated to a terminal velocity of 12.2 meter per second, exerting an average force of 815.8 Newtons. For a 6 foot 5 inch runner, such extreme acceleration results in a massive air resistance drag, adding yet another physical hurdle to the task.
"Our calculated drag coefficient highlights the outstanding ability of Bolt," writes co-author Jorge Hernandez of the National Autonomous University of Mexico. "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."
The mathematical model used by the researchers revealed that although Bolt generated 81.58 kilojoules of energy during the sprint, only a fraction of this accounted for his net motion towards the finish line. According to the calculations, 92.21 percent of the generated energy was used to offset the drag of air resistance.
This distribution of power persisted throughout the entire sprint, as Bolt achieved his maximum output of 2,619.5 watts less than a second into the race. To give an idea of how far Bolt pushed himself, 2619.5 watts is enough to power a dishwasher.
The researchers also note the inherent difficulty of performing well in modern championships. "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," they explain.
Beyond highlighting the physical wonders of Bolt's record sprint, the mathematical model used by the researchers allows for more precise and diverse measurements of athletic performance in similar cases. As the authors of the study point out, the actual time it takes a runner to cross the finishing line is only part of the performance.
"If more data become available in the future, it would be interesting to see what distinguishes one athlete from another," continued Jorge Hernandez.