How to do crunches - Tips & crunch exercises
Crunches are a classic core exercise and one of the most effective ways to strengthen the abdominal muscles. Learn about technique, what muscles are worked and get examples of different types of crunches to try out on your next workout.
Starting position
Lie on your back with your knees bent and feet flat on the floor.
Place your hands lightly behind your head or cross them over your chest.
Relax your neck and keep your chin slightly tucked.
Lift your upper body
Engage your core and press your lower back gently into the floor.
Lift your head, shoulders, and upper back off the floor in a controlled motion.
Focus on bringing your rib cage toward your pelvis rather than pulling with your neck.
Lower with control
Slowly lower your upper body back down until your shoulders touch the floor.
Maintain tension in your core throughout the movement.
Remember to breathe correctly
Exhale as you crunch up.
Inhale as you lower back down.
Crunch exercise variations
How to: Lie on your back with knees bent, lift your shoulders off the floor by engaging your abs, then lower with control.
Muscles worked: Rectus abdominis.
How to: Alternate bringing opposite elbow and knee together while extending the other leg in a controlled motion.
Muscles worked: Rectus abdominis and obliques.
How to: Lift your hips off the floor by pulling your knees toward your chest while keeping your upper body relaxed.
Muscles worked: Lower rectus abdominis.
How to: Stand tall and bend your torso to the side, bringing your elbow toward your hip, then alternate sides.
Muscles worked: Obliques.
How to: Kneel facing a cable machine, crunch your torso downward by pulling your ribs toward your pelvis.
Muscles worked: Rectus abdominis.
How to: Kneel facing a cable machine, crunch your torso downward by pulling your ribs toward your pelvis.
Muscles worked: Rectus abdominis.
How to: Hold a dumbbell at your chest, perform a crunch by lifting your shoulders off the floor, then lower slowly.
Muscles worked: Rectus abdominis.
How to: Lift your upper body and legs at the same time to form a V shape, then lower with control.
Muscles worked: Rectus abdominis and hip flexors.
What muscles are worked during crunches?
Crunches primarily target the abdominal muscles and play a key role in building core strength and control.
Different crunch variations shift the focus slightly, allowing you to emphasize specific areas of the core.
Primary muscles
Rectus abdominis
The main muscle responsible for spinal flexion. It is heavily activated in regular crunches, dumbbell crunches, kneeling cable crunches, reverse crunches, and V crunches.Obliques
Located on the sides of the abdomen and responsible for rotation and side bending. They are especially targeted in bicycle crunches and standing side crunches.
Secondary muscles
Hip flexors
Assist in lifting the legs and pelvis, particularly during reverse crunches and V crunches.Deep core stabilizers
Including the transversus abdominis, which helps stabilize the spine and maintain core tension across all crunch variations.Lower back muscles
Provide support and stability to the spine during controlled crunch movements.
Common mistakes during crunches and how to avoid them
Technique and form is, as with any exercise, very important to get the best results and reduce the risk of injury. Here are three common mistakes during crunches and how you can avoid them.
1. Pulling on the neck
What happens?
Hands pull the head forward instead of the abs doing the work.
Risks
Neck strain and reduced abdominal activation.
Solution
Keep hands light on the head or cross arms over the chest.
Focus on lifting the shoulders, not the head.
2. Using momentum
What happens?
Swinging the upper body instead of controlling the movement.
Risks
Less core activation and higher risk of lower back discomfort.
Solution
Slow down the movement.
Pause briefly at the top of each rep.
3. Not engaging the core
What happens?
The lower back arches off the floor.
Risks
Increased strain on the lower back and less ab engagement.
Solution
Press the lower back into the floor before each rep.
Think about pulling the rib cage toward the pelvis.