Core · Bodyweight
Leg Extension Star Crunch
How to do the leg extension star crunch, the muscles it works, and the mistakes to avoid. Pulled straight from the Kovo app's exercise library.
- Equipment
- Bodyweight
- Difficulty
- Beginner
- Logged as
- Weighted reps
- Movement
- Flexion
- Mechanic
- Isolation
How to do it
Lie on your back in a wide star shape with arms and legs spread. Simultaneously crunch up, drawing one knee and the opposite hand together over your midline, then extend back out flat to the star, alternating sides.
- 1Abs folding the ribcage toward the hips on each crunch
- 2Hand and opposite knee meeting over your center
- 3A full stretch back into the star between reps
Common mistakes
- Yanking the neck to lift the shoulders
- Using momentum instead of a controlled crunch
- Keeping the shoulders flat instead of curling up
Muscles worked
The leg extension star crunch mainly works the upper abs and lower abs, with the obliques and hip flexors assisting.
- Upper AbsPrimary
- Lower AbsPrimary
- ObliquesSupport
- Hip FlexorsSupport
- QuadsMinor
Kovo programs the leg extension star crunch for you and tracks it every session.
We build your whole program, drop the right lifts into each workout, and adjust your weights as you get stronger. Free on iOS and Android.
More abs & core exercises
- How to do the ab wheel rollout
- How to do the ankle tap plank
- How to do the ankle taps
- How to do the resistance band dead bugs
- How to do the resistance band pallof press
- How to do the rollout
Last reviewed June 2026.