How to Do the Vertical Leg Crunch

Proper Form, Variations, and Common Mistakes

Verywell / Ben Goldstein

Also Known As: Crunch up

Targets: Abdominals

Level: Intermediate

The vertical leg crunch is a great core exercise. It is similar to the basic crunch, except that the legs are perpendicular to the floor. This position increases the intensity of the exercise, so it is a good next step after you've mastered the basic crunch. It can help your reach your goal of flatter and more attractive abs and a strong core. You can use this exercise as part of a core workout or a total body workout.


The rectus abdominis is the chief target of the basic crunch. The vertical leg crunch not only increases the rectus abdominis workout, it is effective for recruiting the lower back extensors, the transverse abdominals, and even the external obliques and internal obliques.

Building your core muscles will increase your metabolism, which is key to burning fat throughout the day, even when you're not exercising. The vertical leg crunch helps improve your balance and posture by recruiting muscles along your spine. Changing up your ab routine is part of getting a full core workout, and there are variations and options to help you expand your ab exercise repertoire.

Step-by-Step Instructions

Lie on your back on a mat or another surface that will be comfortable.

  1. Place your hands folded behind your neck.
  2. Bring your legs up, extending them perpendicular to the floor with knees slightly bent. Keep your lower spine flat on the floor.
  3. Contract your abs in preparation for the lift.
  4. Begin by slowly curling your upper body, lifting your shoulder blades off of the floor. Exhale on the upward motion. Keep your legs straight and pointed upward; don't let them sway or list to one side.
  5. Continue curling your body upward using your core muscles. Don't lead with the head by pulling on the neck, and keep your chin up.
  6. When your shoulder blades are off of the floor, pause and hold the position a moment or two.
  7. Begin lowering the upper body by uncurling slowly. Inhale on the downward motion. Don't allow your legs to sway, and don't let them crash back to the floor. This should be a slow and controlled descent.
  8. Keep your legs in the fixed starting position.
  9. Do 3 sets of 12 to 16 reps.

Common Mistakes

Avoid these errors to get the most from this exercise and to avoid strain or injury.

Swaying Legs

Use your core muscles to prevent leg motion. You don't want them to tilt to one side or you could strain your back. If you find your legs are unwieldy and hard to control during the lift, you can cross your legs to help stabilize them.

Head and Neck Position

Your neck should always be in line with your torso. Avoid pulling on your head or neck to draw your shoulders off the ground. Your hands should only be gently resting behind your head. Keep your chin up as you raise your upper body. Don't tilt your head forward as that can place strain on your neck. It also means your abs are doing less of the work as you try to do some of it with the upper body and back.

Using Momentum

The movement should come from a contraction of the abs, not from swaying forward with your upper body.

Modifications and Variations

The crunch is an exercise that can be done in many ways to make it more accessible as you build core strength or to work your muscles in different ways. Using a mat or other soft surface beneath the back is important—pushing your spine into a hard floor can be very uncomfortable.

Need a Modification?

If you can't come fully up when you start, go as far as you can and return to the starting position. You'll improve as you practice.

Up for a Challenge

Rather than supporting your head with your hands, you can extend your arms toward your toes during the crunch.

For a greater challenge, place a weight on your chest or hold one behind your head.

Safety and Precautions

If you have any back or neck problems, talk to your doctor or physical therapist about whether crunches are appropriate for you. If not done with proper form, they can compress the spine and stress the neck. Avoid crunches after the first trimester of pregnancy, as soon as the belly expands.

Try It Out

Incorporate this move and similar ones into one of these popular workouts:

By Elizabeth Quinn, MS
Elizabeth Quinn is an exercise physiologist, sports medicine writer, and fitness consultant for corporate wellness and rehabilitation clinics.