Lying Scissor Crunch
- Target muscle
- Iliopsoas, Rectus Abdominis
- Synergist muscles
- Obliques, Quadriceps, Tensor Fasciae Latae
- Equipment
- Body weight
- Body part
- Waist
- Type
- Strength
The lying scissor crunch is a bodyweight core exercise that combines an upper-body crunch with alternating scissor-style leg kicks, simultaneously targeting the iliopsoas and rectus abdominis. The obliques, quadriceps, and tensor fasciae latae all assist in stabilizing and driving the movement. It is an efficient drill for building coordinated hip-flexor and abdominal strength in a single, continuous motion.
How to do the Lying Scissor Crunch
- 1Lie flat on your back on the floor with your legs extended and your hands placed lightly behind your head, elbows wide.
- 2Lift both legs a few inches off the floor and brace your core so your lower back presses firmly into the ground.
- 3Curl your head, neck, and upper shoulders off the floor into a crunch position and hold it throughout the set.
- 4Raise your right leg to roughly 45 degrees while keeping your left leg low and hovering just above the floor.
- 5In one controlled motion, switch the leg positions — lower the right leg and raise the left — in a smooth scissor-like alternating kick.
- 6Continue alternating legs in a steady rhythm, keeping the crunch held constant so the rectus abdominis stays under tension the entire time.
- 7Breathe steadily throughout — exhale as you switch legs rather than holding your breath.
- 8After completing your target number of reps or time, lower both legs and your upper body to the floor together with control.
Form tips
- Keep your lower back pressed into the floor at all times — any gap between your lumbar spine and the ground means the iliopsoas is overloaded and the abs have lost tension.
- Hold the crunch position constant rather than bobbing your head up and down with each scissor switch, so the rectus abdominis works continuously.
- Keep the leg movement deliberate and controlled; wide, slow scissors demand more from the hip flexors and obliques than rapid, shallow kicks.
- Avoid pulling on your neck with your hands — rest your fingertips lightly behind your head and let your abs do the work of holding the curl.
- Focus on keeping the non-rising leg close to the floor without letting it touch down, which maintains tension on the iliopsoas throughout.
Common mistakes
- Letting the lower back arch off the floor during the scissor kicks, which shifts load away from the rectus abdominis onto the lumbar spine and can cause strain.
- Dropping the crunch between leg switches, which interrupts tension on the rectus abdominis and turns the exercise into simple leg raises rather than an integrated core movement.
- Making the leg kicks too short and rapid, which reduces the range of motion and limits the demand placed on the iliopsoas, quadriceps, and tensor fasciae latae.
- Pulling the neck forward with the hands to compensate for weak abs, which strains the cervical spine and takes effort away from the target muscles.
- Holding the breath through the set, which spikes blood pressure and forces you to rush the kicks once you run out of air — exhale on each leg switch to keep the rhythm steady and the core braced.
Frequently asked questions
What muscles does the lying scissor crunch work?
The primary muscles are the iliopsoas and rectus abdominis. The obliques, quadriceps, and tensor fasciae latae act as synergists, assisting with leg stabilization and the alternating scissor kicks throughout the movement.
How is the lying scissor crunch different from regular crunches or leg raises?
Unlike a standard crunch, the scissor crunch adds alternating leg kicks that heavily recruit the iliopsoas and tensor fasciae latae alongside the abs. Unlike plain leg raises, the held crunch keeps the rectus abdominis under continuous tension, making it a more demanding combined movement.
How do I stop my lower back from lifting off the floor?
Before you begin, press your lower back firmly into the floor and brace your core hard. Keep the non-rising leg as low as possible without letting it touch down — if your back starts to arch, raise the lower leg a little higher or reduce the range of the scissor until your core strength improves.
How many sets and reps should I do?
Three to four sets of 10 to 20 total leg switches (5 to 10 per side) is a good starting range. You can also work for time — 20 to 30 seconds per set — gradually extending duration as your hip-flexor and core endurance builds.
Can beginners do the lying scissor crunch?
Yes, though beginners should shorten the range of the scissor kicks and keep the lower leg higher off the floor until the lower back stays flat consistently. Mastering a standard crunch and basic leg raise separately first will make the combined movement easier to control.
