Crunch (straight leg-up)
- Músculo objetivo
- Rectus Abdominis
- Músculos sinergistas
- Iliopsoas, Obliques
- Equipamiento
- Body weight
- Parte del cuerpo
- Waist
- Tipo
- Strength
The crunch (straight leg-up) is a bodyweight ab exercise that primarily targets the rectus abdominis, with the iliopsoas (hip flexors) and obliques assisting. You perform it lying on your back with your legs raised straight toward the ceiling, crunching your torso up toward your feet. Raising the legs increases the range over the upper abs and limits momentum, making it a strong core builder for the waist.
Cómo hacer el Crunch (straight leg-up)
- 1Lie flat on your back on a mat with your legs raised straight up toward the ceiling, so your hips are flexed to roughly 90 degrees and your legs are vertical.
- 2Place your hands lightly behind your head or across your chest, and keep your chin a fist's width off your chest.
- 3Brace your core and flatten your lower back into the floor to remove any arch.
- 4Exhale and curl your shoulder blades off the floor, reaching your torso up toward your feet rather than just lifting your head.
- 5Pause briefly at the top with your abs fully contracted, keeping your legs straight and still.
- 6Inhale and lower your shoulder blades back to the floor under control without dropping or relaxing fully.
- 7Keep your legs vertical throughout, then complete your reps and lower your feet to the floor.
Consejos de técnica
- Lead with your sternum, not your neck: imagine pushing your chest toward your toes so the rectus abdominis does the work.
- Keep the movement slow and controlled, taking about two seconds up and two seconds down to maximize tension on the abs.
- Exhale hard at the top of each rep to deepen the contraction and brace your core.
- If your hamstrings are tight and your legs drift forward, keep a soft bend in the knees while still pointing the soles toward the ceiling.
Errores comunes
- Pulling on your head and neck with your hands, which strains the cervical spine and takes load off the abs.
- Letting your legs swing or drop toward you to create momentum, which cheats the rep and shifts work to the hip flexors instead of the rectus abdominis.
- Arching the lower back off the floor, which reduces ab tension and can stress the lumbar spine.
- Crunching too far by trying to sit all the way up, which recruits the iliopsoas more than the abs and shortens the time the abs stay loaded.
Preguntas frecuentes
What muscles does the crunch (straight leg-up) work?
It primarily works the rectus abdominis, with the iliopsoas (hip flexors) and obliques assisting to stabilize the torso and keep the legs raised.
How is this different from a regular crunch?
A regular crunch has your feet planted with knees bent. Raising the legs straight up fixes the hips at about 90 degrees, which limits momentum and emphasizes the upper abs through a controlled range.
Is the crunch (straight leg-up) good for beginners?
Yes. It is a bodyweight movement with no equipment, and you can bend your knees slightly to make it easier while you build core strength and learn to keep your lower back flat.
How many sets and reps should I do?
Start with 2 to 3 sets of 12 to 20 slow, controlled reps. Add reps or a brief pause at the top before adding any load, since this is a bodyweight exercise.
Where should I feel this exercise?
You should feel it in your abs, especially the upper rectus abdominis. If you mainly feel it in your hip flexors or lower back, slow down, flatten your back, and keep your legs from swinging.
