Flexion Leg Sit Up (Bent Knee)

Lie down on your back with your knees bent and feet flat on the ground. Place your hands behind your head or crossed over your chest. Slowly curl your upper body off the ground, bringing your chest towards your knees. Pause for a moment and then lower your upper body back down to the starting position. Repeat for the desired number of repetitions.

How to perform the Flexion Leg Sit Up (Bent Knee)

  1. Set up. Set up in a stable, balanced starting position appropriate for the Flexion Leg Sit Up (Bent Knee) using your body weight.
  2. Brace and execute. Brace your core, control the descent, and move through a full pain-free range of motion while emphasizing your abdominals.
  3. Reset. Reverse the movement under control and reset between repetitions, keeping your form crisp on every rep.

Coaching cues

  • Move with intent — every rep should feel deliberate, not rushed.
  • Drive force through your abdominals rather than momentum.
  • Keep your breathing steady: exhale on the hard part, inhale on the reset.

Common mistakes

  • Using too much weight and losing positional control.
  • Cutting the range of motion short and missing the target muscle.
  • Letting your spine round or hyperextend instead of staying neutral.

Detailed cues, common mistakes, and demonstration video are available in the Fitly app.

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