How to Do the Double Crunch (Video)

How to Do the Double Crunch (Video)

Most of us can’t spend the entire day working on our abs — we just want to look like we do. In order to get a chiseled core without a major time investment, it’s key to find abs exercises that offer the most benefit with the least effort. And few fit the bill quite like the double crunch exercise.


Benefits of the Double Crunch

The double crunch combines two killer abs exercises — the standard and the reverse crunch — into one. When performed correctly, the double crunch will effectively engage more core muscles than doing either abdominal crunch on its own. This two-in-one move will target your obliques, hip flexors, and rectus abdominis (i.e., the “six-pack” muscle).

Contrary to popular belief, you don’t have “upper” or “lower” abs; the rectus abdominis is a single sheet of muscle. “Either the whole thing contracts or it doesn’t,” says Trevor Thieme, C.S.C.S. In other words, you can’t work the upper section without also bringing the lower section into the act.

That said, by combining two moves in one, the double crunch exercise maximizes the amount of work performed by your abs. In fact, it’ll hit just about every square inch of your core musculature — and get you one step closer to nailing that coveted six-pack.


How to Do the Double Crunch With Perfect Form

Appears in: 21 Day Fix >> 10-Minute Fix for Abs

  • Lie on your back with your knees bent and feet flat and hip-distance apart on the floor. Gently place your fingertips on the sides of your head. This is the starting position.
  • Contract your abs to lift your shoulders and upper back off the floor as you also lift your feet and bring your knees toward your elbows.
  • Squeeze your abs at the top of the movement, and then return to the starting position.


How to Make the Double Crunch Easier

If you’re having difficulty with the full movement, don’t lift your shoulders or curl your knees as much. You can also try the vertical leg crunch, in which you perform a standard crunch while keeping your legs straight and perpendicular to the floor.


How to Make the Double Crunch Harder

If you’re looking for more of a challenge, don’t let your feet touch the floor for the duration of each set. Keeping your feet elevated will increase your abs’ time under tension, a key trigger for muscle growth, Thieme says.


Bonus Tips for Doing the Double Crunch

In order to prevent injury, resist the urge to round your lower back. Instead, keep your lower back pressed into the floor as you lift your knees; tilt your pelvis and shoulders toward your belly button as you contract your abs.


Muscles Targeted by the Double Crunch

Rectus Abdominis

This long core muscle runs from your sternum to the bottom of your pelvis and works to flex your spine. If you shed enough fat from your midsection, this muscle can also become visible, with a segmented appearance that is often referred to as a six-pack.

Hip Flexors

Your hip flexors are located at the front of your hips and connect the lower body, pelvis, and abdomen. Their primary function is to… wait for it… flex the hip. They’re actively engaged when you raise your knee toward your chest (as when performing a double crunch) and passively engaged when you’re in a seated position.


There are two types of obliques: external and internal. Your external obliques run from your lower ribs to your pelvis along the outer edges of your torso, while your internal obliques are located just below them. Together, your external and internal obliques work to rotate and stabilize your trunk.