Lying Crunch (straight legs)
- Zielmuskel
- —
- Equipment
- Body weight
- Körperregion
- Waist
- Typ
- Strength
The lying crunch with straight legs is a body-weight core exercise that targets the muscles of the waist and abdominal region. Keeping the legs extended increases the lever arm and the demand on the core compared to a standard bent-knee crunch. It is a practical movement for building core endurance and improving trunk flexion strength without any equipment.
Lying Crunch (straight legs): So führst du sie aus
- 1Lie flat on your back on a mat with your legs fully extended and your feet together.
- 2Extend your arms along your sides or cross them over your chest — avoid pulling on your neck.
- 3Engage your core by gently drawing your navel toward your spine.
- 4Exhale and curl your head, shoulders, and upper back off the mat by flexing your trunk, lifting as high as you can while keeping your lower back in contact with the floor.
- 5Hold the top position for one count and feel the contraction through your waist and core.
- 6Inhale and slowly lower your upper back, shoulders, and head back down to the mat under control.
- 7Repeat for the desired number of repetitions without losing core tension between reps.
Technik-Tipps
- Keep your lower back pressed into the mat throughout the movement — avoid lifting the lumbar spine off the floor.
- Focus on curling your ribcage toward your pelvis rather than simply lifting your head forward.
- Breathe out on the way up and in on the way down to maintain intra-abdominal pressure and core stability.
- Move slowly and deliberately; momentum shortens the range of motion and reduces core activation.
- Place your tongue on the roof of your mouth to help keep your neck in a neutral position and reduce strain.
Häufige Fehler
- Pulling on the head or neck with the hands, which strains the cervical spine and takes tension away from the core.
- Using momentum to swing the torso up instead of contracting the core, reducing muscle activation and increasing injury risk.
- Lifting the lower back entirely off the mat, which turns the movement into a sit-up and shifts stress away from the target muscles.
- Holding the breath throughout the set, which spikes intra-thoracic pressure and reduces stability.
- Rushing through reps without a controlled eccentric phase, which limits time under tension and results in weaker adaptations.
Häufig gestellte Fragen
What muscles does the lying crunch with straight legs work?
This exercise primarily targets the muscles of the waist and core, including the rectus abdominis and the obliques. Keeping the legs straight increases the challenge compared to a bent-knee variation by lengthening the lever arm.
What is the difference between a crunch and a sit-up?
A crunch involves a partial trunk curl that lifts only the shoulders and upper back off the floor while keeping the lower back grounded. A sit-up takes the torso all the way up toward the thighs, also engaging the hip flexors. Crunches isolate the core more directly.
Why keep the legs straight instead of bending the knees?
Straight legs create a longer lever that increases the load on your core, making the movement more challenging. It also prevents you from using your hip flexors to 'cheat' by anchoring bent knees, forcing the abdominals to do more of the work.
How many reps should I do?
For core endurance, 3 sets of 15–25 controlled reps works well. If you are training for strength, keep reps lower (8–12) and focus on slow, deliberate contractions. Quality of movement matters more than rep count.
Is this exercise suitable for beginners?
Yes. The lying crunch with straight legs requires no equipment and is low impact. Beginners should start with a slow tempo and a modest number of reps, focusing on keeping the lower back flat and avoiding neck strain before progressing to higher volumes.
