Flexion Leg Sit up (bent knee)
- Zielmuskel
- Rectus Abdominis
- Synergistenmuskeln
- Iliopsoas, Obliques, Quadriceps
- Equipment
- Body weight
- Körperregion
- Waist
- Typ
- Strength
The flexion leg sit up (bent knee) is a bodyweight core exercise that primarily targets the rectus abdominis (abs), with the hip flexors (iliopsoas), obliques, and quadriceps assisting through the movement. Performing it with the knees bent reduces lower-back strain and makes it a solid choice for building trunk strength and endurance.
Flexion Leg Sit up (bent knee): So führst du sie aus
- 1Lie on your back on a mat with your knees bent to roughly 90° and your feet flat on the floor, hip-width apart.
- 2Place your hands lightly behind your head or crossed over your chest, keeping your neck relaxed.
- 3Brace your core and tuck your chin slightly so your head stays in line with your spine.
- 4Curl your upper body off the floor, lifting one vertebra at a time until your torso is close to your thighs.
- 5Exhale as you rise and keep your feet planted, using your abs rather than yanking on your neck.
- 6Pause briefly at the top with your abdominals fully contracted.
- 7Lower yourself back down under control, inhaling as your shoulders return to the mat.
- 8Repeat for your target reps, keeping tension on the abs throughout the set.
Technik-Tipps
- Lead the movement with your sternum and roll up segment by segment rather than jerking up in one piece.
- Keep your hands resting lightly behind your head so you never pull on your neck to complete a rep.
- Exhale on the way up and inhale on the way down to keep your core braced and stable.
- Lower slowly to make the abs work on the eccentric portion instead of dropping back to the floor.
- Anchor your feet only if needed; relying on them less keeps the load on the abs instead of the hip flexors.
Häufige Fehler
- Pulling on the back of your head with your hands, which strains the neck and takes work away from the abs.
- Bouncing or using momentum to swing up, which reduces tension on the rectus abdominis and cheats the rep.
- Letting the lower back arch off the floor at the bottom, which stresses the spine and breaks core bracing.
- Straightening the knees during the set, which shifts the effort onto the hip flexors and increases lower-back strain.
- Holding your breath instead of exhaling on the way up, which weakens your brace and limits the contraction.
Häufig gestellte Fragen
What muscles does the flexion leg sit up (bent knee) work?
It primarily works the rectus abdominis (abs), with the hip flexors (iliopsoas), obliques, and quadriceps assisting as synergists.
Why do the bent-knee sit up instead of a straight-leg version?
Bending the knees reduces the pull of the hip flexors on the lower spine, lowering back strain and shifting more of the work onto the abs. It is a safer, more controlled choice for most lifters.
Is the bent-knee sit up good for beginners?
Yes. It uses only body weight and the bent-knee position is gentler on the lower back, so it suits beginners building core strength. Start with strict, slow reps before adding volume.
How many sets and reps should I do?
For most people, 2–4 sets of 12–20 controlled reps works well. Since it is a bodyweight movement, focus on full range and tempo rather than chasing high numbers.
Where should I feel this exercise?
You should feel it in your abs (rectus abdominis), with some involvement from the obliques and hip flexors. If you mostly feel it in your neck or lower back, reduce momentum and stop pulling on your head.
