Medicine Ball Crunch
- Primary muscleAbs
- EquipmentMedicine Ball
- DifficultyIntermediate
- TypeCore · Core flexion
- Secondary muscles
- Obliques, Hip Flexors, Serratus Anterior
- Body part
- Core
- Position
- Lying
- Laterality
- Bilateral (both sides together)
- Category
- Strength
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A medicine ball hugged against your chest adds load without changing the crunch's mechanics, and unlike a plate it will not dig into your sternum across a long set. Progression is simply the next ball up; when the heaviest one feels light, move the load overhead or to a cable rather than chasing endless reps.
How to do the Medicine Ball Crunch
- Lie supine with knees bent ~90° and feet hip-width apart; hold the medicine ball against your chest with elbows tucked.
- Posteriorly tilt the pelvis to lightly flatten the low back; brace the abs and keep the neck neutral with a slight chin tuck.
- Exhale and curl the trunk, lifting head, shoulders, and upper back until the shoulder blades just clear the floor; keep the ball touching your chest.
- Pause briefly and squeeze the abs; do not pull with the arms or jut the chin forward.
- Inhale and lower slowly, placing the spine back down segment by segment until the shoulder blades touch.
- Maintain a small, controlled range and steady tension; stop if you feel low-back discomfort or hip flexor dominance.
Tip: Breathe out as you crunch and let the last bit of air leave the lungs at the top of each rep.
Muscles worked
Primary
Abs · Core
The rectus abdominis shortens to bend the spine forward, and each rep should end with the upper abs fully contracted and the ribs pulled down.
Secondary
- Obliques — Twisting or side crunch variations bring the obliques in, and you should feel them along the side of the waist on the working side.
- Hip Flexors — The hip flexors take over if your feet are anchored and you come up too high; keep the range short to leave them out.
- Serratus Anterior
Common mistakes
- Pulling on the neck — hands behind the head should support, not yank; keep the elbows wide and the chin about a fist away from the chest.
- Sitting all the way up — a crunch is a curl of the ribs toward the pelvis, not a sit-up; the lower back should stay on the floor the whole time.
- Cranking out fast reps — momentum does the work if you bounce; lift to a squeeze, hold for a count and lower slowly.
- Never adding load — once bodyweight reps get easy, hold a plate on the chest or use a cable rather than doing sets of 50.
Where it fits in a workout
Crunches close out a session after the heavy work, or they can fill the rest periods between sets of a lift that does not need much bracing. Pair a cable crunch with a cable side bend on the same stack.
How many sets, how heavy and how hard: see what the ACSM position stands support.
Variations and alternatives
Similar exercises
Without medicine ball
When to talk to someone
- Chest discomfort, feeling faint or lightheaded, or trouble breathing during or after exercise can be signs of a heart attack. In the US, call 911 right away; elsewhere, call your local emergency number.
- Heart, metabolic or kidney disease, or symptoms like these when you are active: talk to your doctor before you start or step up training.
- Pregnant: ask your obstetric care provider which exercise suits you.
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Sources
- ACSM position stand on exercise quantity and quality (Garber et al., 2011)
- ACSM preparticipation health screening (Riebe et al., 2015)
- ACOG Committee Opinion No. 804 on exercise in pregnancy (2020)
- CDC: About Heart Attack Symptoms, Risk, and Recovery (2024)
Sources checked on October 17, 2026. Full citations are in the exercise library.
Animation and exercise data: ExerciseDB, licensed to SetGrip. General information, not medical or coaching advice.