Flexion Leg Sit Up (bent Knee)
The point of Flexion Leg Sit Up (bent Knee) is a trunk that resists rather than folds; pure bodyweight leverage is how it gets there.
How to do Flexion Leg Sit Up (bent Knee)
- Lie flat on your back with your knees bent and feet flat on the ground.
- Place your hands behind your head with your elbows pointing outwards.
- Engaging your abs, slowly lift your upper body off the ground, curling forward until your torso is at a 45-degree angle.
- At the same time, lift your legs off the ground, bending your knees and bringing them towards your chest.
- Pause for a moment at the top, then slowly lower your upper body and legs back down to the starting position.
- Repeat for the desired number of repetitions.
Flexion Leg Sit Up (bent Knee) Sets and Reps by Goal
Strength
4 sets of 6-8 reps at your hardest clean leverage, resting 2-3 minutes. Hold the end position for a beat once reps come easily.
Hypertrophy
4 sets of 12-18 reps with 60 seconds of rest. Add reps first, then slow the lowering phase.
Endurance
3 sets of 25-30 reps with 30-45 seconds of rest. Change leverage or elevation before you add load.
Common Flexion Leg Sit Up (bent Knee) Mistakes
Adding reps forever instead of making the movement harder
Change leverage, elevation, or tempo once you clear your rep range.
Holding your breath through the hardest part of the rep
Exhale as you brace so the ribs stay down and pressure stays controlled.
Letting the last set decay into a different exercise
End the set when the pattern changes, not when the reps run out.
Easier and Harder Than Flexion Leg Sit Up (bent Knee)
Swap Flexion Leg Sit Up (bent Knee) For
Flexion Leg Sit Up (bent Knee) — Frequently Asked Questions
How do you do the Flexion Leg Sit Up (bent Knee)?
Lie flat on your back with your knees bent and feet flat on the ground. Place your hands behind your head with your elbows pointing outwards. Engaging your abs, slowly lift your upper body off the ground, curling forward until your torso is at a 45-degree angle. Use your bodyweight only and keep the movement controlled through the full range. The animated GIF above shows the complete rep at normal speed.
What muscles does the Flexion Leg Sit Up (bent Knee) work?
The Flexion Leg Sit Up (bent Knee) primarily targets the abs. It is classified as a core exercise and is performed with your bodyweight only.
How many sets and reps of the Flexion Leg Sit Up (bent Knee) should I do?
For muscle growth: 4 sets of 12-18 reps with 60 seconds of rest. Add reps first, then slow the lowering phase. Adjust the load rather than the rep target if form breaks down before the final rep.
Is the Flexion Leg Sit Up (bent Knee) good for beginners?
It is an intermediate movement. You will get more out of it once you can already perform the basic core patterns with controlled form. Beginners can still use it with light load and close attention to technique.
What can I do instead of the Flexion Leg Sit Up (bent Knee)?
Try the Lever Kneeling Twist, Barbell Sitted Alternate Leg Raise (female) or the Weighted Russian Twist V. 2. Each trains the abs with a similar movement pattern, so you can swap based on the equipment you have available.
