Side Plank

How to do it

Lie on your side with your elbow directly under your shoulder. Stack your feet (or stagger them if stacked feels wobbly). Lift your hips so your body forms a straight line from head to ankles. Rest your top arm on your hip or reach it to the ceiling. Breathe steadily through the hold.

Why it's good for runners

Every running stride loads one side of your body at a time, and your trunk has to keep you from collapsing sideways. The side plank trains exactly that — the obliques and hip muscles that keep your hips level when you're tired.

Common mistakes

Hips sagging toward the floor is the most common fault, as is rotating forward out of the stacked position. If your hips drop, end the set — a few clean seconds beats a long, ugly sag.