Crunches (How To, Muscles Worked, Benefits)

Crunches are a classic, go-to ab exercise that isolates the rectus abdominis (your “six-pack” muscle) using a short, controlled range of motion. They’re simple, effective, and great for building core awareness and strength—especially in the upper portion of the abs. When performed with good form, crunches are a solid foundational core movement for all fitness levels.

Primary Muscles Worked: Rectus Abdominis (Upper Abs)
Secondary Muscles Worked: Obliques (Stabilizers)
Equipment Needed: None (mat optional for comfort)

---

How To Do Crunches

Step-by-Step Instructions

1. Set-Up:
   • Lie on your back with your knees bent at 90 degrees and feet off the floor, hip-width apart.
   • Cross your arms over your chest or place your fingertips lightly behind your ears (avoid pulling on your neck).
   • Press your lower back into the floor and engage your core.
2. Execution:
   • Contract your abs to lift your head, shoulders, and upper back just a few inches off the floor.
   • Pause briefly at the top and squeeze your abs.
   • Lower back down slowly with control, keeping tension in your core.
3. Tips for Proper Form:
   • Keep your chin slightly tucked (like holding a tennis ball under your chin).
   • Focus on lifting your ribcage toward your pelvis—not pulling your neck forward.
   • Keep your lower back pressed into the ground the entire time.

---

Key Benefits

• Effectively isolates the upper abs with minimal equipment.
• Builds core awareness and control.
• Easy to modify for beginners or progress for more advanced core work.

---

Modifications and Variations

• Easier Option: Keep your hands across your chest and reduce the range of motion.
• Harder Option:
  • Add a pause at the top.
  • Hold a small weight or medicine ball at your chest.
  • Perform on a decline bench for increased resistance.

---

Common Mistakes

• Pulling on the Neck: If hands are behind your head, don’t yank—use your abs to lift.
• Using Momentum: Keep the movement slow and deliberate.
• Not Engaging the Core: Press your lower back into the ground and stay braced.

---

Reps and Sets Recommendations

• For Beginners: 3 sets of 10–12 controlled reps.
• For Core Endurance: 3–4 sets of 15–20 reps.
• As a Finisher: 2–3 sets to failure with slow, focused reps.

Crunch Variations

What to change your workout up just a bit. Here are a couple of Crunch variations:

Oblique Crunches

By adding a little bit of a twist to the crunch, you can target your obliques with Oblique Crunches. You can simply twist toward the top of the crunch, taking (one at a time) each elbow towards it’s opposite knee.

Or, to make things simpler, place one foot flat on the floor and rest the opposite foot on that knee. Now you can crunch up, taking the opposite elbow toward the knee that is now up in the air.

Weighted Crunches

If crunches start to become too easy, you can ramp up the difficulty by holding onto weight.

You can hold a dumbbell or a plate just over the chest and head area to add some extra resistance to your crunches.

Crunch Alternatives

If you can’t do crunches, for whatever reason, or you’re just wanting a different ab exercise option – here are a couple of Crunch alternatives:

Seated Crunches

For seated crunches, sit down on the edge of a bench with knees and feet close together.

Crunch by lifting your knees up towards your chest. Use your hands on the bench for support if necessary.

Sky Crunches

Sky Crunches are very similar to a crunch, but the position of the legs is different.

Keep the legs straight and laying straight down on the ground. Now, simply crunch straight up to the sky (hence the name!). Remember to keep your chin lifted up off your chest throughout the movement.

Exercises to Superset with Crunches

Looking to add some supersets to your program? Here are a couple of my favorite exercises to pair with Crunches:

Russian Twists

Why: Russian Twists target the obliques, providing a comprehensive workout that complements the focus of crunches on the central abdominal muscles.

Mountain Climbers

Why: Mountain Climbers engage both your core and lower body, enhancing overall stability and strength, which makes for a dynamic pairing with Crunches.

Need more superset options? Check out my 10 favorite exercises to superset with Crunches.

Final Thoughts

Crunches are a great core exercise and I like to incorporate them both into the warm-up at lower volumes and at the end of workouts in higher volumes and usually combined with at least one or two other core exercises.

They’re one of those unique exercises that are both very beginner-friendly, yet still highly effective and used by elite-level athletes as well.

Share This