This advanced move will fire up the entire abdominal wall and works your shoulders, too.
- Begin in a side elbow plank with your left elbow down and your right hand behind your head.
- Keeping your torso stable and your waist lifted, bring your right leg up toward your shoulder to lightly tap your right elbow.
- Lengthen your right leg back to the starting position to complete one rep.
- Do as many reps as you can in 30 seconds and then switch sides for another 30 seconds.