Beyond Crunches: The Best Ab Exercises You Should Be Doing

Go fast to make this core exercise more about cardio, or move slowly to focus more on the abs.

• Start in a traditional push-up starting position — shoulders over hands and weight on just your toes.
• Bring your right foot forward, bending the knee and putting weight on the ball of your foot.
• Swiftly switch legs, bringing the left knee forward while moving the right leg back. It feels a little like running in place in a plank position. This counts as two reps.
• Complete 30 reps.