What I've Learned

When driving on the turnpike at 65 miles per hour, I often think about the cheetah, which can run 70 miles per hour. Were my Toyota edible, it would be lunch.

The reason a cheetah can run faster than the I-95 speed limit has to do with fast twitch muscle fibers.

Most mammals (perhaps all, I don't know) have two types of muscle fibers, slow twitch and fast twitch. Humans tend to have about an equal number of each type.

Slow twitch fibers don't generate much force, but they don't tire easily, either. These allow us to stand upright and to walk.

Fast twitch muscle fibers can generate great power, but tire easily. These allow us to run or swing a tennis racket.

Champion sprinters have more – a lot more – fast twitch fibers in their leg muscles than do average people.

Champion distance runners – marathoners, for example – have more slow twitch fibers.

There is debate in scientific and athletic communities about whether training can turn one type of muscle fiber into the other. Do people become sprinters because they have more fast twitch fibers, or do they have more fast twitch fibers because they became sprinters?

Sports trainers will say heck yes training can change fiber types, but scientists want conclusive evidence. As of now, the question is wide open.

The cheetah, a big cat seemingly built for speed, has a lot of fast twitch fibers in its hind legs. It also has fast twitch fibers in the muscles along its flexible spine, which allows the back to assist the legs in propelling the body forward.

A cheetah can go from zero to 70 faster than a sports car. In a mere four strides it can go from standing still to top speed. However, it can only maintain that speed for a couple of hundred yards, then it has to rest.

Because of its spotted coat, the cheetah is sometimes mistaken for a leopard, but to the knowing eye, the difference is obvious. The cheetah has a smaller, almost aerodynamic head. Its face has a black stripe running down from the inside corner of each eye, looking like teardrop stains.

These are believed to do for the cheetah what black stripes under the eyes do for football players, help cut the reflected glare from the face.

Also, cheetahs are smaller and leaner, and hunt during the day, whereas leopards hunt mostly at night.

Unlike other big cats, the cheetah can't fully retract its claws. This provides it with nature's equivalent of studded tires, giving good traction.

The main prey of cheetahs is the gazelle, which is no slouch, either, when it comes to speed. A gazelle can run 50 miles per hour.

With a 20 mile per hour advantage, you'd think a cheetah would catch a gazelle on every hunt, but not so. A cheetah is successful only about 50 percent of the time. In a chase, it tries to trip its prey, then clamp onto the throat with its jaws, strangling it.

If a gazelle can avoid being tripped – or, if tripped, get up and away before its throat is captured – a cheetah will, after a minute or two, have to stop from exhaustion. Those fast twitch fibers tire easily.

To better its chances of catching a gazelle, the cheetah uses good stalking techniques, trying to get within 30 to 100 feet of its prey before the chase begins. It moves forward stealthily when the gazelle lowers its head to bite off some grass. When the gazelle raises its head to chew, the cheetah, with impeccable timing, will either crouch and freeze or simply freeze.

There are videos on the Internet of cheetahs stalking, and there are slow motion videos of them running. Both actions are things of beauty and grace. Unless you are a gazelle. Or a Toyota.