Exercise guide
Lying Crunch Straight Legs
- Beginner
- Isolation
- Rep-based
- Waist
The Lying Crunch with straight legs isolates the rectus abdominis by minimizing hip flexor involvement and providing a stable base for spinal flexion. It is an effective variation for building core definition and improving abdominal control.
Reviewed by the Crucible team · Updated June 2026
Muscles worked
Setup
- Lie flat on your back on a mat with your legs fully extended and feet together.
- Place your hands lightly behind your head with elbows flared out, or cross them over your chest.
- Press your lower back firmly into the floor to eliminate any arch in your spine.
How to do it
- Exhale and contract your abdominals to lift your shoulder blades 2-3 inches off the floor.
- Keep your legs straight and heels glued to the ground throughout the movement.
- Pause at the top of the contraction for one second, focusing on squeezing your ribs toward your hips.
- Inhale as you slowly lower your upper body back to the starting position with a controlled 2-second tempo.
Form checklist
- Keep your lower back pressed into the mat at all times.
- Avoid pulling on your neck; your hands should only provide light support.
- Maintain a space about the size of a tennis ball between your chin and your chest.
- Ensure your legs remain stationary and do not lift off the floor.
Pro tips
- Focus on 'peeling' your shoulder blades off the floor rather than just lifting your head to ensure the abs are doing the work.
- Visualize your abdominal wall shortening as you crunch to maximize the mind-muscle connection.
Make it harder
- Extend your arms straight overhead to increase the lever length and resistance.
- Hold a light weight plate or dumbbell against your chest while performing the movement.
Frequently asked
- What muscles does the lying crunch straight legs work?
- The lying crunch straight legs primarily targets the abs and obliques, and also works the erector spinae as secondary muscles.
- What equipment do you need for the lying crunch straight legs?
- The lying crunch straight legs requires no equipment — just your body weight.
- Is the lying crunch straight legs good for beginners?
- Yes. The lying crunch straight legs is a beginner-friendly movement and a strong foundation to build on.