The human speed limit

We investigate secrets of speed and ask could you ever run as fast as the Flash?

In 2009, Jamaican athlete Usain Bolt broke the World Record for the 100-metre sprint, blazing the distance in just 9.58 seconds. That’s an average speed of about 23 miles per hour (mph) – faster than cars drive past your school – and saw him crowned the fastest man on Earth.

One day, someone may break Bolt’s record, but just how fast could a human move? Could people reach superhuman speeds, running like the fictional superhero Barry Allen, also known as the Flash?

Pushing the limits

Lots of different factors control how fast you can run. These include your weight, stride length (how long your steps are), your diet and the strength of your muscles. The speed that sound travels through air is 761mph in normal conditions. This is known as Mach 1 (named after German scientist Ernst Mach). According to The Flash TV series, Barry Allen’s top speed is Mach 3.3 (2,532mph), but researchers at the University of Leicester calculated his maximum speed to be Mach 13 (almost 10,000mph) based on his diet.

Peter Weyand, a scientist who studies the limits of human sporting performance, thinks that people could reach speeds of up to 40mph. When you run, your leg muscles contract, generating a force to push your feet into the ground and propel you forwards.