Lie on your left side on a mat. Prop yourself up on your forearm, making sure your shoulder is directly over your elbow. With your legs fully extended, stack your right foot on top of your left.
Press into your left foot and elbow to lift your hips up into a side plank, forming a straight line from head to heels. Keep your neck long, and make sure your hips are stacked; don't allow your hips to tilt forward or backward.
Hold this position for 30 seconds, then repeat on the other side.