Weighted Crunches
Weighted crunches take the standard floor crunch and add a medicine ball held against your chest, giving your abdominals more resistance to work against once the bodyweight version feels too easy. You lie on your back with knees bent, curl your shoulder blades off the floor using your abs, then lower back down under control. It's a simple, direct way to keep progressing ab strength without needing a cable machine or a bench.
Why it works
A crunch is a short-range spinal flexion, your abdominals shortening to lift your shoulder blades off the floor rather than sitting all the way up the way a full sit-up does. That short range keeps the tension concentrated on your abs instead of spreading it into your hip flexors, which take over more as the range increases. Holding a medicine ball against your chest adds resistance directly in line with that flexion, so your abs have to produce more force to lift the same distance, which is the most direct way to keep this movement challenging as bodyweight crunches become easy.
Set up
- Lie on your back with your knees bent and feet flat on the floor.
- Hold a medicine ball against your chest with both hands.
- Keep your lower back pressed gently into the floor.
- Tuck your chin slightly, as if holding a small ball under it.
How to do it
- Curl your shoulder blades up off the floor using your abdominals.
- Keep the ball held tight against your chest throughout the lift.
- Pause briefly at the top of the curl.
- Lower back down under control until your shoulder blades touch the floor again.
- Repeat for the set without resting your head fully between reps.
Form cues
- Lower back stays pressed into the floor the whole rep.
- Only your shoulder blades lift, not your whole torso.
- Chin stays tucked, not jutting forward to help you up.
- The ball stays glued to your chest, never swung for momentum.
Breathing: Exhale as you curl up, inhale as you lower back down.
Common mistakes
Pulling on the neck with the hands to help curl up.
Fix: Hold the ball against your chest instead; if your hands are behind your head, you're likely using your arms instead of your abs.
Lifting the whole torso like a sit-up instead of just the shoulder blades.
Fix: Keep the range short; your hip flexors take over once you rise further than your shoulder blades leaving the floor.
Letting the lower back arch off the floor between reps.
Fix: Keep gentle tension in your abs throughout the set so your lower back stays pressed down rather than resetting into an arch.
Swinging the medicine ball for momentum.
Fix: Keep the ball still against your chest; any swing is taking work away from your abdominals.
How to program it
- As a light, bodyweight-plus-light-load isolation movement for one muscle group, 2 to 3 times a week is a reasonable frequency for most people.
- Two to three sets of 12 to 20 reps works well, increasing the ball's weight gradually once that range stops feeling challenging.
- It fits naturally near the end of a session, as finishing work after your main strength or cardio training is done.
Safety notes
- Keep the range short and controlled; a full sit-up range with added weight pulls more load into the lower back and hip flexors than the exercise intends.
- If you feel neck strain, check that your hands are supporting the ball rather than pulling on your head.
Exercise profile
- Force
- Pull
- Mechanics
- Isolation
- Category
- Strength
Frequently asked questions
How much weight should I use for weighted crunches?
A light medicine ball, around 4 to 8 pounds, is plenty to start. Increase only once your current weight stops feeling challenging for your full set.
How many reps of weighted crunches should I do?
Two to three sets of 12 to 20 reps is a solid range, with more weight added gradually rather than more reps piled on.
What can I do without a medicine ball?
A standard bodyweight crunch trains the exact same pattern, and an exercise ball crunch adds an instability challenge if you want variety without extra weight.
Why do I feel this in my neck instead of my abs?
That usually means your hands are pulling on your head instead of supporting the ball. Hold the weight against your chest and let your abs, not your arms, do the lifting.