Lying Vertical Crunches (Legs Straight Up)
The lying vertical crunch with legs straight up is a bodyweight core exercise that performs the crunch with the legs extended vertically. The raised leg position increases the difficulty of the crunch by removing hip flexor assistance and demanding greater rectus abdominis activation.
How to do it
- Lie flat on your back and raise both legs straight up toward the ceiling, perpendicular to the floor.
- Place your hands behind your head or cross your arms over your chest.
- Engage your abs and lift your shoulder blades off the floor, reaching your hands toward your feet.
- Pause at the top, then slowly lower your upper body back down.
- Repeat for the desired number of repetitions.
Form cues
- Keep your legs as straight as possible pointing toward the ceiling.
- Exhale as you lift your shoulder blades off the floor.
- Reach your fingertips up toward your toes.
- Keep your lower back gently pressed into the mat throughout the movement.
- Lower your upper body slowly with control.
Breathing: Exhale as you crunch upward and reach for your feet, then inhale as you lower your upper body back to the floor.
Common mistakes
- Pulling on your neck with your hands because it strains the cervical spine and shifts work away from the abs.
- Using momentum to swing upward because it reduces muscle activation and makes the movement less effective.
- Bending the knees too much because it decreases the challenge on the upper abs by engaging hip flexors.
Muscles worked
Primary: abs. Secondary: hip flexors.
Suggested sets & reps
Get fitter
3 sets x 10-12 reps, rest 60 seconds
Lose weight
3 sets x 12-15 reps, rest 45 seconds
Build muscle
3 sets x 8-12 reps, rest 60 seconds
Easier, harder & alternatives
Alternatives
Take care if…
- If you feel neck pain, support your head gently or pause the exercise.
- If you have lower back discomfort, keep your knees slightly bent or choose a gentler floor crunch.
General educational guidance, not medical advice. Stop on sharp pain and check with a qualified professional if unsure.
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Start free →Frequently asked questions
What if I cannot keep my legs completely straight?
It is completely fine to keep a slight bend in your knees if your hamstrings are tight. Focus on keeping your legs as vertical as comfortable.
Why do my neck muscles hurt during this exercise?
Neck strain usually happens when you pull your head up with your hands. Support your head lightly and let your abdominal muscles do the lifting.
How often can I do vertical crunches?
You can include this exercise 2 to 3 times per week, allowing at least a day of rest between core sessions for recovery.