Twist Crunch (leg-up)
- Target muscle
- Iliopsoas, Obliques, Rectus Abdominis
- Synergist muscles
- Quadriceps, Tensor Fasciae Latae
- Equipment
- Body weight
- Body part
- Waist
- Type
- Strength
The twist crunch (leg-up) is a bodyweight core exercise performed on the floor with your legs raised, combining a crunch with a rotational twist to directly target the obliques and rectus abdominis while the elevated-leg position places constant demand on the iliopsoas. The quadriceps and tensor fasciae latae assist in stabilizing the raised legs, making it an efficient multi-muscle ab movement for building rotational core strength.
How to do the Twist Crunch (leg-up)
- 1Lie flat on your back on the floor. Raise both legs so your thighs are vertical and your knees are bent at roughly 90°, shins parallel to the floor.
- 2Place your hands lightly behind your head with your elbows wide, or cross them over your chest — whichever keeps you from pulling on your neck.
- 3Brace your core and press your lower back gently into the floor to establish a stable starting position.
- 4Exhale and curl your upper body upward, lifting your shoulder blades off the floor while simultaneously rotating your right elbow toward your left knee.
- 5Pause at the top of the movement for a brief squeeze, feeling the contraction in your obliques and rectus abdominis.
- 6Slowly lower back to the starting position under control, keeping your legs raised throughout.
- 7On the next rep, rotate your left elbow toward your right knee, alternating sides with each repetition.
- 8Complete your target reps, then lower your legs and release the contraction to finish the set.
Form tips
- Keep your chin off your chest — imagine holding an orange under your chin to maintain a small gap and reduce strain on your neck.
- Drive the rotation from your ribcage, not from pulling your elbows. Your elbow is just a reference point; the oblique does the twisting work.
- Hold your legs at a consistent height throughout the set — letting them drift down reduces the iliopsoas demand and shifts load away from the intended muscles.
- Control the descent on every rep; lowering slowly under tension recruits more muscle fibers than dropping back quickly.
- Exhale on the way up as you crunch and twist; inhale as you return to the start to maintain intra-abdominal stability.
Common mistakes
- Pulling on your head with your hands, which strains the cervical spine instead of loading the abs — keep your hands light and your neck neutral.
- Using momentum to swing up rather than contracting the core, which turns the exercise into a rock rather than a controlled crunch and reduces oblique activation.
- Letting your lower back arch off the floor at the start, which transfers stress to the lumbar spine — actively press your back down and brace before each rep.
- Rotating only the elbow across the body without true trunk rotation, which cheats the obliques of their full range — rotate from the ribcage so the shoulder crosses the midline.
- Dropping your legs between reps to rest, which removes the hip-flexor load and breaks the continuous tension that makes the leg-up position more challenging than a standard twist crunch.
Frequently asked questions
What muscles does the twist crunch (leg-up) work?
It primarily targets the obliques, rectus abdominis, and iliopsoas. The quadriceps and tensor fasciae latae act as synergists, helping to stabilize your legs in the raised position throughout the set.
Why raise your legs instead of keeping your feet on the floor?
Raising your legs keeps constant demand on the iliopsoas while removing your feet as an anchor, so you cannot push off the floor to cheat the crunch. It also holds your pelvis in a slight posterior tilt, which makes it easier to keep your lower back flat and forces the abs and obliques to produce the rep.
Is the twist crunch (leg-up) suitable for beginners?
It can be, but beginners should first master a basic crunch and learn to brace the core properly. If you feel neck strain or cannot maintain the raised-leg position for the full set, start with feet flat on the floor and progress from there.
How many sets and reps should I do?
For core endurance and definition, 3 sets of 12–20 alternating reps (6–10 per side) works well. Rest 30–60 seconds between sets. Focus on a slow, controlled tempo rather than rushing through the reps.
What is a good alternative to the twist crunch (leg-up)?
The bicycle crunch is the closest alternative — it adds a pedaling leg motion that extends the hip-flexor challenge while still targeting the obliques and rectus abdominis. A standard twist crunch with feet on the floor is a useful regression if the leg-up position is too demanding.
