20-Minute Ab and Butt Workout Guaranteed to Leave You Sore Tomorrow

Reps: 20 reps, alternating sides

• Start in an elbow plank with your palms facing up.
• With your abs pulled toward your spine, reach your right arm forward keeping your torso as still as possible. Bring your elbow back to the mat. This completes one rep.
• Repeat on the other side and continue alternating sides for 20 reps total.

Elbow planks work the entire front of the body, but adding the arm reach forces your abs to kick into high gear to stabilize your torso.