The Tokyo Olympics hosted the 100-meter dash, where the world's fastest sprinters came together to compete for gold. Lamont Marcell Jacobs finished the race in 9.80 seconds, bringing Italy its first ever gold medal in this event. The women's race saw Jamaica win the gold, silver and bronze. Elaine Thompson Herah led the sweep with a time record of 10.61 seconds, breaking the 33-year-old Olympic women’s record.They could not touch the legacy of Usain Bolt of Jamaica, an eight-time Olympic gold medalist. He retired in 2017, but still holds the title of fastest living human. Bolt completed the 100m in 9.58 seconds. Bolt ran the 100 meters in 9.58 seconds. That's less than the speed of a cat. Yes, it is a house cat. Bolt would not be able to beat pronghorns and cheetahs in a race against the fastest animals on the planet.It might seem that speed is determined by the muscle size. More strength equals more speed. Although that may be true to some extent, an elephant cannot outrun a gazelle. What determines the maximum speed?A group of scientists, led by Michael Gnther (biomechanist), set out to discover the laws of nature that govern the maximum running speed in the animal kingdom. A new study, published in the Journal of Theoretical Biology last week, presents a complex model that considers size, leg length, muscle densities, and other factors to determine which body design elements are most crucial for optimizing speed.This research gives insight into the evolutionary process of legged animals, as well as their gaits. Ecologists could use it to study how speed restrictions on animal movement affect population, habitat selection, community dynamics, and species-specific dynamics. Biomedical engineers and roboticists could learn more about the optimal body structure for speed to improve their designs of prosthetics and bipedal walking machines.Gnther explains that the project goal is about understanding evolution and how it shapes our bodies. This question can be answered mechanistically to really understand how the body is affected by evolutionary requirements, such as being fast.Myriam Hirsch, German Center for Integrative Biodiversity Research, has done previous research in this area. She found that speed was linked to animals metabolism. This is the process by which an animal converts nutrients into fuel. A finite amount of this fuel is stored in muscle fibers for sprinting. Because it takes longer to accelerate heavier animals, Hirts' team discovered that larger animals use less of this fuel. This phenomenon is called muscle fatigue. This is why a human could theoretically outrun a Tyrannosaurus Rex.Gnther and his coworkers were skeptical. He said that he thought they might be able give another explanation. One that relied only on classical physics to explain the speed limitations. They created a biomechanical model that included over 40 parameters related to body design, running geometry, and the balance between the competing forces on the body.Robert Rockenfeller (a University of Koblenz–Landau mathematician who coauthored this study) says that speed is limited by two factors. The first is drag, also known as air resistance. This opposing force acts on each leg to propel the body forward. Drag's effects don't increase with weight, so it is the dominant factor that limits speed for smaller animals. Rockenfeller states that air drag would allow you to run infinitely fast if you were infinitely overweight.
