Core
The side plank is the most fundamental lateral core-stabilization exercise. Supported on one forearm and the side of the foot, you hold the body in a straight horizontal line, training the obliques and lateral core isometrically.
Place the forearm on the floor with the elbow directly under the shoulder. Stack the feet (or stagger them for more stability). Raise the hips until the body forms a straight line. Hold without letting the hips drop.
3×30-45 seconds per side with perfect technique.