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In 2009, Jamaican sprinter Usain Bolt set the current world record in the 100 meters, clocking 9.58 seconds at the IAAF World Championships in Athletics in Berlin. Between 60 and 80 meters into this record-setting sprint, Bolt reached an incredible velocity of 27.8 miles per hour (44.64 km/h) – the fastest human footspeed ever recorded. For most of us, that kind of speed seems hard to imagine. But according to some researchers, Bolt's record run isn't even close to what the human body could theoretically achieve.
Although the longstanding assumption was that the force of limbs striking the ground was the main limiting factor on an athlete's speed, biomechanics researchers have suggested that the human body can withstand significantly more ground forces than what is experienced during top-speed running. Instead, it is the contractile speed of our muscle fibers that seems to impose a natural limit.
In a 2010 study that looked at ground forces, foot-ground contact times, and the top forward and backward running speeds of people on a treadmill, researchers suggested that a human would have to reach a speed of 35 or 40 mph before experiencing near-maximum ground forces. So while it may be biologically possible for our limbs to apply and withstand more force than what is achieved by an Olympic sprinter, the real question is how quickly our muscles can get us off the ground after each step.
Run like the wind:
- The peak ground forces that a sprinter can apply in just one step can reach 800 to 1,000 pounds, or around four to five times the athlete's body weight.
- Scientists from Southern Methodist University, Rice University, and the University of Wyoming took part in the research, which was published in the Journal of Applied Physiology.
- For a Japanese game show in 2011, US sprinter Justin Gatlin (who has, incidentally, received two drug-related bans from competition) clocked 100 m in 9.45 seconds – with the assistance of giant fans providing him with a massive tailwind.
- The 100-m world record for women – 10.49 seconds – was set by Florence Griffith-Joyner at the US Olympic Trials in 1988. Later that year, Griffith-Joyner also set the still-standing world record in the 200 meters, with a time of 21.34 seconds.