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The Physics of Running Fast (with Running Shoes)


To run fast you need to be able to maintain your speed. Your shoes have one chance to slow you down and that’s when your foot hits the ground. Let’s look at the ground-foot interphase. When your foot strikes the ground, the ground exerts a force on your leg. This force is then passed along to your center of mass. The component of the force in a vertical direction is what keeps you from falling to the ground. The horizontal component of the force is what slows you down. Running fast is all about reducing or eliminating this breaking force.

To reduce breaking, move your foot fall closer to your hips, as shown. Let’s compare these side by side (see photo above)

In both cases, the magnitude of the force is the same, but on the right photo the force applied to the center of mass is more vertical, and so the breaking force has been reduced. In the example below, the runner has reduced the breaking force even more.

Let us now look at all 3 cases together. You can readily see the progression from most to least breaking.

So remember, the key to running fast is to let off the breaks.

Of course, a good running shoe makes a big difference. The traction, the cushion, and the weight of the shoe are important factors that influence running speed. You can find a big variety of running shoes at really low prices from top brands at FinishLine.com.

Read also: The Physics of Running Shoes