Usain Bolt

The Physics of Usain Bolt’s World Record 100-meter Dash

The Physics of Usain Bolt's World Record 100-meter Dash

Back in 2009, Jamaican sprinter Usain Bolt ran the 100-meter dash in a record setting time of 9.58 seconds. A recent study highlights the astounding physics behind this unprecedented human achievement.

An interesting thing about Bolt is that he’s 6ft 5in tall. That means he needs to expend a bit more energy than the average sprinter in order to overcome the drag caused by wind resistance; he’s actually not very aerodynamic relative to other runners. But that said, his record was the biggest increase since timing was introduced in 1968. He’s truly a freak of nature.

According to a mathematical model that now appears in the European Journal of Physics, Bolt’s maximum power occurred when he was less than one second into the race — but while he was running at only half his eventual maximum speed, which registered at the jaw-dropping rate of 12.2 meters per second (40 feet/second), or 43.92 km/h (27 mph).

His acceleration out of the the starting blocks clocked in at 9.5 meters per second squared, (31.2 ft/s2, which is almost 0.97 g (the acceleration due to Earth’s gravity), and he generated an incredible 2.6 kilowatts of power (3.5 horsepower) less than a second later.

The study also showed that less than 8% of the energy his muscles generated was used for motion, the rest absorbed by drag. The physicists suspect that Bolt makes up for his large frame and slow reaction-time by virtue of his tremendous stride and fast twitch muscle fibres.

Interestingly, Bolt ran the 100-meters with a slight wind at his back. But even without that assist, calculations showed he would have finished the race only 0.1 second slower — which would still have still resulted in a world record.

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