Weighted Crunches
The weighted crunch is the classic trunk curl performed with a plate held on the chest or in extended arms, to add resistance for the upper part of the rectus abdominis.
ABS · CORE
How it is executed
- Lie on your back with your knees bent and feet flat on the floor.
- Hold a weight plate against your chest or with your arms extended upward.
- Engage your core and lift your shoulders a few inches off the ground, keeping your lower back on the floor.
- Lower with control.
- The added weight increases resistance and intensifies the upper-ab activation.
- Muscles worked
- Abs
- Primary muscle
- Upper abs
- Equipment
- Other
- Movement pattern
- Core
- Difficulty
- Intermediate
- What it is for
- Core strengthHypertrophyStabilityStrength
Common mistakes
- Pulling with the neck to come up. With a plate on the chest it is easy to jut the chin forward to gain height, and the effort goes to the neck instead of the abs. Keep a fist of space between chin and chest and look at the ceiling through the whole set.
- Lifting the lower back off the floor. If the low back comes up, the movement becomes a hip flexion and the hip flexors take over. Stop the range once the shoulder blades are off the floor and the lower back is still down.
- Choosing a plate so heavy the reps come up with momentum. The weighted crunch is done slowly, with a pause at the top and a controlled descent. If you need to swing the arms or bounce, go down a plate.
- Dropping the torso on the way down. The return to the floor is half the stimulus, and with extra load it matters even more. Lower over two or three seconds without releasing the tension in the abs.
Frequently asked questions
- What muscles does the weighted crunch work?
- The star is the rectus abdominis, especially its upper portion, which pulls the ribs toward the pelvis. The obliques help as stabilizers, and the hip flexors barely take part as long as the range stays at lifting the shoulders off the floor. The plate does not change which muscles work; it only raises the load they have to overcome.
- How much weight should you use on a plate crunch?
- Start with a light plate, around 5 to 10 kilos, and check that you can do 10 to 15 controlled reps without pulling on the neck or lifting the lower back. The abs respond well to sets taken close to failure, so if you reach 20 reps easily it is time to move up a plate. Holding it with the arms extended overhead makes the same weight harder.
- Weighted crunch or machine crunch: which one should you choose?
- Both load the same movement, spinal flexion. The plate crunch needs only a free weight and makes you control the lower back position yourself. The machine fixes the pivot and lets you raise the load in small steps, which makes it more convenient for progressing over months. Training at home or with little equipment, the plate does the job; with a machine available, alternate the two.
- How do you keep the neck from straining on the weighted crunch?
- The neck gets loaded when the chin juts forward to gain height. Keep about a fist of space between chin and chest, fix your eyes on a point on the ceiling and think about bringing the ribs toward the pelvis, not the head toward the knees. Holding the plate against the chest rather than behind the head keeps the arms from pulling on the neck.
Sources and editorial approach
The explanation, variations and FAQs are Kaizer’s editorial synthesis. ACSM’s 2026 guidance provides general context on progression and resistance training in healthy adults; it does not independently validate the technique of each variation.
No individual professional review is recorded for this page.
Put it to work in Kaizer
Create workout routines with AIFrom goals and equipment to an editable routine in minutes — one that keeps adapting itself, session by session.The best Hevy Coach alternatives in 2026The alternatives, including what each one does better.Pricing and plansBasic supports up to 3 clients from USD 5 a month.
