Crunch

Muscles Worked

How to Perform

1. 1

   Setup: Lie on your back with knees bent at 90 degrees and feet flat on the floor, hip-width apart. Place your hands lightly behind your head with elbows out wide, or cross your arms over your chest. Keep your lower back pressed gently against the floor.

2. 2

   Engage: Take a breath in, then exhale as you begin the movement. Draw your belly button toward your spine to engage the transverse abdominis. Think about shortening the distance between your ribcage and pelvis before you move.

3. 3

   Curl Up: Flex your spine and lift your shoulder blades off the ground by curling your ribcage toward your pelvis. The movement is small—only 30-45 degrees off the floor. Your lower back should stay on the ground throughout. Focus on spinal flexion, not hip flexion.

4. 4

   Squeeze: At the top of the movement, pause for a one-second squeeze, maximally contracting your abs. Exhale forcefully at this peak contraction to increase muscle engagement. Your chin should stay neutral, not tucked to chest or thrown back.

5. 5

   Lower: Control the descent back to the starting position over 2-3 seconds. Keep tension in your abs—don't just drop. Your shoulder blades should lightly touch the ground before the next rep. Maintain consistent tempo without momentum or bouncing.

Common Mistakes

• Pulling on Your Neck

  Using your hands to pull your head forward creates dangerous neck strain and removes tension from your abs. Your hands are just there for support—the movement comes entirely from spinal flexion, not arm pull.

• Coming Up Too Far

  Sitting all the way up turns it into a hip flexor-dominant movement and reduces ab engagement. The crunch is a small, controlled motion focusing on spinal flexion, not full trunk flexion like a sit-up.

• Using Momentum

  Rocking or using momentum to bounce up defeats the purpose of the exercise. Each rep should be slow and controlled with a pause at the top. If you're using momentum, you're doing too many reps or need to slow down.

• Holding Your Breath

  Breathing incorrectly reduces ab activation and can spike blood pressure. Exhale forcefully as you crunch up and squeeze your abs. Proper breathing mechanics actually increase the effectiveness of each rep.

Pro Tips

• Think Small, Controlled Movement

  The crunch is about quality over quantity. A 30-degree trunk curl with maximum contraction builds more muscle than 100 sloppy reps to 90 degrees. Keep the range small and the tension constant throughout the set.

• Anchor Your Lower Back

  Press your lower back into the floor throughout the entire movement. This posterior pelvic tilt protects your spine and ensures your abs, not hip flexors, do the work. Imagine flattening your spine against the ground.

• Add Resistance Progressively

  Once you can do 20+ perfect reps, progress by holding a weight plate on your chest or doing them on a decline bench. Your abs are muscles too—they need progressive overload to grow stronger and more defined.

• Use a 3-1-3 Tempo

  Take 3 seconds to curl up, hold the contraction for 1 second, then 3 seconds to lower. This time under tension approach maximizes muscle engagement and makes bodyweight crunches brutally effective without needing hundreds of reps.

Variations

Alternatives

Related Core Exercises