Crunch

Illustration of a man performing a crunch exercise, showing the start and finish positions. The abdominal muscles are highlighted in orange.

Exercise Description

The Crunch is a classic bodyweight abdominal exercise that primarily targets the rectus abdominis, the muscle responsible for flexing the spine and creating the “six-pack” appearance. Unlike a full sit-up, the crunch involves lifting only the head, shoulders, and upper back off the floor, keeping constant tension on the abdominal muscles while minimizing involvement from the hip flexors.

Primary Muscles Worked

  • Rectus Abdominis

Secondary Muscles Worked

  • External Obliques

  • Internal Obliques

  • Transverse Abdominis

  • Hip Flexors (Minimal Involvement)

  • Serratus Anterior (Stabilization)

How to Perform Correctly

Setup

  1. Lie flat on your back on an exercise mat.

  2. Bend your knees and place your feet flat on the floor approximately hip-width apart.

  3. Place your hands lightly behind your head or crossed over your chest.

  4. Engage your core and gently press your lower back into the floor.

  5. Keep your head and neck in a neutral position.

Movement

  1. Contract your abdominal muscles to lift your head, shoulders, and upper back off the floor.

  2. Focus on curling your ribcage toward your pelvis rather than simply lifting your head.

  3. Raise only until your shoulder blades clear the floor.

  4. Pause briefly at the top while squeezing your abdominals.

  5. Slowly lower yourself back to the starting position under control.

  6. Maintain tension in your core throughout the exercise.

  7. Repeat for the desired number of repetitions.

Common Mistakes to Avoid

Pulling on the Neck

  • Use your abdominal muscles to lift your torso rather than pulling your head forward with your hands.

Using Momentum

  • Perform slow, controlled repetitions instead of jerking the body upward.

Lifting Too High

  • Turning the movement into a sit-up increases hip flexor involvement and reduces abdominal isolation.

Holding the Breath

  • Maintain steady breathing throughout the exercise.

Allowing the Lower Back to Arch

  • Keep your lower back gently pressed into the floor.

Rushing the Repetitions

  • Focus on quality contractions rather than speed.

Looking at the Ceiling

  • Keep your chin slightly tucked and neck neutral throughout the movement.

Abs Exercises