<P> The key determinant of footspeed in sprinting is the predominance of one distinct type of muscle fibre over another, specifically the ratio of fast - twitch muscles to slow - twitch muscles in a sprinter's physical makeup . Though fast - twitch muscles produce no more energy than slow - twitch muscles when they contract, they do so more rapidly through a process of anaerobic metabolism, though at the cost of inferior efficiency over longer periods of firing . The average human has an almost - equal ratio of fast - twitch to slow - twitch fibers, but top sprinters may have as much as 80% fast - twitch fibers, while top long - distance runners may have only 20% . This ratio is believed to have genetic origins, though some assert that it can be adjusted by muscle training . "Speed camps" and "Speed Training Manuals", which purport to provide fractional increases in maximum footspeed, are popular among budding professional athletes, and some sources estimate that 17% to 19% of speed can be trained . </P> <P> Though good running form is useful in increasing speed, fast and slow runners have been shown to move their legs at nearly the same rate--it is the force exerted by the leg on the ground that separates fast sprinters from slow . Top short - distance runners exert as much as four times their body weight in pressure on the running surface . For this reason, muscle mass in the legs, relative to total body weight, is a key factor in maximizing footspeed . </P> <P> The record was 44.72 km / h (27.8 mph), seen during the final 100 meters sprint of the World Championships in Berlin on 16 August 2009 by Usain Bolt . (Bolt's average speed over the course of this race was 37.58 km / h or 23.35 mph .) Maximum human sprint speed is strikingly slower than that of many animals . Compared to other land animals, humans are exceptionally capable of endurance, but incapable of great speed . For example, cheetahs can attain short bursts of speed well over 100 km / h (62 mph), the American quarter horse has topped 88 km / h (55 mph), greyhounds can reach 70 km / h (43 mph), and the Mongolian wild ass has been measured at 64 km / h (40 mph). Even the domestic cat may reach 48 km / h (30 mph). </P>

How fast can a human run in km/h