How fast can a human possibly run 100 meters?

In 2008, Usain Bolt won Olympic gold, setting the 100 meter world record.

In the 2008 Olympics. Usain Bolt not only won Olympic gold, he outclassed all of his rivals and became the first human to break through the 9.70 second barrier.

His 9.69 second finish was bettered in 2009: running 9.58 seconds.

With an automatic time of 9.572 seconds (adjusted for a wind assistance of 0.9 m/s to 9.58 seconds), Usain Bolt’s performance in the 2009 World Championships remains the fastest a human has ever run a 100 meter race.

No other runner, before or since, has broken the 9.60 second barrier.

Although runners Tyson Gay, Yohan Blake, Asafa Powell, and Justin Gatlin have all run 100 meter times between 9.69 and 9.75 seconds, only Usain Bolt has broken the 9.6 second barrier.

But with the ideal human:

• anatomy,
• start,
• acceleration,
• endurance,
• and top speed,

how fast could we run a perfect 100 meter race?

A physiological analysis of various components of the forces on a runner when their feet are and are not in contact with the ground, based on real world analysis of elite runners.

Initially, you must wait 0.10 seconds after the gun before moving; any faster is a false start.

In 2011 at the World Athletics Championships in South Korea, a single false start disqualified world record holder Usain Bolt from the 100 meter race. Reacting to the gun faster than 0.1 seconds results in a false start, as humans cannot react quicker than that.

Human reaction time is limiting; any faster is evidence for anticipating the gun.

This table shows the average age and reaction times of finalists at 100 meter events in the Women’s World Athletics Championships from 1999 through 2019. Although there is substantial variation in reaction times, reacting faster than 0.1 seconds always results in a false start.

Elite sprinters can apply peak forces of 800-1000 pounds (3560-4450 Newtons) to each limb.

The anatomy of a human leg under tension for running (blue) and hopping (red) gaits. Human legs achieve maximum forces of 800-1000 pounds while running, and up to 30% greater while hopping. Beyond ~1300 pounds of force, human bones will break.

Beyond ~1300 pounds, ideal human leg bones would surely break.

US Sprinter Christian Coleman is one of the fastest starters and accelerators in sprint history, and is arguably the world’s most superior runner at distances of 60 meters and under. His lower top speed than other sprinters kept him from making the US Olympic teams in the 100 and 200 meters in 2024, as he placed 4th in both events at the Olympic trials.

During the fastest starts, humans accelerate at rates up to 7.0 meters/second².

This 2007 photo shows a sprinter accelerating out of the starting blocks at the London Grand Prix. The fastest accelerating sprinters with the best reaction times often take the lead in sprints, but must achieve and maintain a high enough peak top speed to hang on for the victory.

The fastest top speed ever achieved by a human was Bolt’s 12.42 meters/second (27.8 mph).

In the fastest race in history, Usain Bolt ran 100 meters in 9.58 seconds, defeating Tyson Gay who finished second in 9.71 and Asafa Powell who finished third, to become the fastest human in world history. His record still stands as of 2024.

However, anatomical studies suggest peak speeds up to 15.6-17.9 m/s (35-40 mph) are achievable.

Although Cheetahs have achieved top speeds that far exceed what a human is capable of, it is anatomically possible for a human to run a 100 meter race in approximately the time it takes a cheetah to cover 200 meters.

In practice, top speeds are sustainable for only 3-4 seconds.

This table shows split times in 10 meter intervals extracted from the races of numerous elite sprinters throughout history. Although these sprinters have comparable top speeds, sustaining that top speed for the entirety of a race is challenging, and is practically limited to 3-4 seconds.

An:

• ideal start (0.10 seconds),
• constant acceleration to top speed (2.56 s),
• and sustaining a 17.9 m/s speed for the race’s remainder (4.31 s),

would yield a time of 6.97 seconds.

Although paralympians are not yet competitive with fully limbed humans over the shortest race sprint distances, there are anatomical advantages that prosthetics offer that may someday lead to them surpassing the current world record.

Any faster, and you’re no longer human.

If we wish to remain bound by the limits of human anatomy, there is clearly a fastest maximum time for a sprinter in the 100 meter dash. However, gene altering, prosthetics, limb lengthening, and even robotic augmentations may someday surpass even the most stringent theoretical limits.

Mostly Mute Monday tells a science story in images, visuals, and no more than 200 words.