As many of you know, I taught Biomechanics last semester at Creighton University. One of the recurring people/performances we referred to was Usain Bolt and the world record he set in the 100m sprint (9.58 seconds); check him out on this YouTube video if you haven’t seen him already. During this race, his top speed is over 27 mph! Absolutely amazing, but is that the fastest we’ll ever see? Are we capable of more? Researchers at Southern Methodist University attempted to determine just that.
Peter Weyand and his colleagues looked at elite sprinters and measured the force the foot generates when sprinting and hopping on one leg. They learned that the foot generates significantly more force during the single-leg hop versus sprinting. This means that elite sprinters are unable to generate enough force when sprinting to achieve maximal speeds. Unfortunately, if they did produce adequate force with each step, that would take too long, thereby slowing the athlete down. According to Weyand, “it’s impossible to run faster and faster and faster without reducing the amount of time that your foot is on the ground.”
So, how do animals (like the cheetah) do it? How do they generate that much more force to run faster? And how do they do so with relatively shorter limbs? Interestingly, “these animals have adapted for speed by developing gait mechanics that prolong their periods of ground force application. These quadrupeds gallop with pronounced backbone bending that increases their foot-ground contact times and length to values that approach those of humans even though their limbs are only half as long. Relatively greater contact lengths and times allow faster running speeds to be attained.”
When all is said and done, Dr. Weyad and his colleagues conclude that faster speeds are indeed possible, maybe up to 35-40 mph!
Weyand, PG, Sandell, RF, Prime, DNL, & Bundle, MW. The biological limits to running speed are imposed from the ground up. Journal of Applied Physiology, In Press. 2010.