Factors Influencing Speed

By Dave Hanks

T-Rex was a scary dinosaur! Could I have run fast enough to avoid him? Thankfully he is extinct and I don’t have that worry. Why can some of us run faster than others and some animal species run faster than other species? Body structure and physiology are major factors.

Newton’s third law of motion is: “That to move forward an animal must push something backwards”. Obviously the quicker one pushes backwards, the faster one can move. An individual’s weight, leg length, stride length, and foot placement are factors. I have personally observed that the faster human athletes have well developed buttocks, and tend to be slightly pigeon toed. Persons that walk with toes pointed outward are not sprinters. I have, also, been told that it is helpful if your second toe is longer than your big one. I suppose that it would be a factor in helping keep one’s stride straight down the track in a line of single file tracks.

But back to animals, the Cheetah (with its flexible spinal column) is the world’s fastest sprinter at 70 mph for short distances. But our American Pronghorn can do 60 mph and has much greater endurance than the Cheetah. They can even race cars, and maintain 40 mph over several miles.

Pronghorns are equipped with an enormous windpipe and oversized lungs. They can take in oxygen three times as fast as other animals of comparable size, and their heart is twice as large as a sheep’s of the same body weight. Their muscle masses are above their legs which allow the legs easier movement and heat diffusion. Those muscles are packed with extra mitochondria for greater energy release. This combined with a large liver allows a large release of glycogen.

The rapid intake of oxygen, combined with extra energy, is essential in critical situations when fleeing to escape a predator. Pronghorn are a holdover from a distance past. Their survival success has a lot to do with their incredible speed.

(Two photos: Ready, Set, Go!)