Exercised: The Science of Physical Activity, Rest and Health

by Daniel E. Lieberman

Avoid overstriding. Get your knees up when you swing your legs forward so you land with a vertical shank and your foot below the knee, not too far in front of the hips. This prevents the legs from landing too stiffly and causing overly high breaking forces that slow you down. Step rate usually increases with speed, but experienced endurance runners generally take 170–180 steps a minute regardless of speed. They thus speed up economically by jumping farther (running is jumping from one leg to another), and a high step rate prevents overstriding. Lean forward slightly, but not too much at the waist. Too much upper-body lean requires you to spend more energy preventing your torso from toppling forward, and it encourages overstriding. Land gently with your feet nearly horizontal. If you are barefoot and don’t overstride, it is almost impossible not to land on the ball of your foot before letting down your heel in what is called a forefoot or mid-foot strike. Forefoot and mid-foot strikes usually don’t generate an impact peak on the ground—a rapid, large collisional force that is painful without shoes. Forefoot and mid-foot strikes also generate rotational forces (torques) that are lower in the knee but higher in the ankle, requiring strong calf muscles and Achilles tendons, which can lead to problems for people trying to transition to this way of running. If you change how your foot lands, do so gradually and build up strength.