Are athletes really getting faster, better, stronger
Are athletes really getting faster, better, stronger?
The question “are athletes really getting faster” is one of the most asked questions in all of athletics.
So what exactly does it mean to get faster? What are some ways that athletes can improve their performance? Is there any evidence that shows that they do or don’t improve their performances? And finally how much time would it take them to become fast enough to compete at a high level with other elite athletes?
In order to answer these questions, we need to first define what it means to be fast. There are several definitions of speed that have been used over the years. One definition is simply “the ability to move quickly through space.” Another definition is “speed” which refers specifically to the rate at which something happens. A third definition is “acceleration,” which refers specifically to the change in velocity (or change in direction) caused by an increase in force applied during acceleration. Finally, there is “power,” which refers specifically to the amount of energy required to produce the desired result.
So what does it mean when someone says that an athlete is getting faster?
Well, if you look at a list of top sprinters from various countries, you will see that many of them have very similar times. They all run between 15-20 seconds per kilometer. However, there are some differences in how they achieve those times. When an elite athlete runs a race his performance is measured with three values: time, distance, and velocity. Even though time, distance, and velocity are all different, they are related by simple multiplication (distance = the velocity * time). This means that you cannot change one without changing one of the others. This means that in order to run faster, an athlete needs either a longer track or longer legs!
We can see this relationship in action by watching the 100m dash. For example, in 1968, American Jim Hines became the first man to break the sound barrier in the 100m dash with a time of 9.95 seconds.
By 2008, Usain Bolt broke that record with a time of 9.69 seconds. During that same time period, the length of the track was the same!
Besides the length of the track, there are a couple of other factors that affect running speed. One of these factors is acceleration.
In 1968, Jim Hines started his run in about 5.2 seconds and reached his peak velocity (his fastest speed) at around 10 meters. When Usain Bolt broke the sound barrier in 2008, he started his run in about 5.0 seconds and reached his peak velocity at around 10 meters. This shows that two athletes can run the exact same time, but if one accelerates faster, then they can both run the same speed. This is because both the distance and time were increased by the same percent (1%).
The other major factor in running speed is gravity. In order to accelerate an athlete must be able to push back against the ground.
This means that there is less upward force holding the athlete against earth’s gravity. The maximum force produced during a sprint is about 2.5 times bodyweight for professional athletes. This means that the faster an athlete runs, the less they are holding themselves back against earth’s gravity. If we assume that an athlete is only able to produce this much force and they push back with 2.5 times their bodyweight, how fast could they run before they fall back due to gravity alone? Using a little math (force = mass * acceleration) we can see that they would be able to run about 13 meters per second. So if an athlete can match or exceed that speed they will remain in contact with the ground, but anything slower and they’ll fall back to earth.
Technology has allowed us to measure how fast these athletes are actually moving. In 2012, during the 100m dash, Usain Bolt reached a top speed of 44.7 meters per second.
However, this is not a constant speed as he is accelerating the entire time. This means that he is producing a force greater than 2.5 times his bodyweight while pushing back against the ground.
A couple of other interesting notes: the top speed for these world-class sprinters is about 5-6 times faster than a normal human can run. It would probably take a force greater than 10 times their bodyweight to achieve this speed and in fact, no human has ever been able to run this fast on Earth.
Even with the forces of gravity substantially less on the moon, the fastest time in 1968 was still only about 2.5 times their bodyweight.
If you’re keeping track that means that Usain Bolt reached a speed of 12.4 times his bodyweight and is applying a force of 4.7 times his bodyweight against earth’s gravity.
The force applied is equal to that of a spacecraft landing on Earth. Pretty crazy!
How does this compare to other animals?
Well, a cheetah can run 70 mph and that requires a force of 4.5 times its bodyweight. A housefly can hit 3.5 times its bodyweight while a jumping spider can apply 12 times its body weight to jump. Compared to the world-class sprinters, these numbers pale in comparison.
If you liked this answer, let me know and I can do some more! If you have any questions, leave them in the comments.
Thanks for reading!
Sources: Wired Magazine: How Fast is Usain Bolt?
New York Times: Usain Bolt and the Limits of Speed (June 2008)
National Geographic: Cheetah Fastest Land Animal (April 2008)
USAToday: Cheetah Speed Record Finally Broken (Aug, 2011)
BreakThroughs: Gecko Foot Replicates Spider Success (Mar 2013)
Thanks to all sites for use of information.
Sources & references used in this article:
- Smarter faster better: the secrets of being productive (D Epstein – TED radio hour, 2014)
- Smarter faster better: the transformative power of real productivity (D Epstein – 2014)
- The great acceleration: How the world is getting faster, faster (D Epstein – 2017)