Flexion Leg Sit Up (Straight Arm)

Lie on your back with your legs extended straight out in front of you. Keep your arms straight and by your sides. Now, lift your upper body off the ground by engaging your abdominal muscles. Bring your legs towards your chest and touch your toes with your hands. Slowly lower your upper body back down to the starting position while simultaneously extending your legs back out straight. Repeat the movement.

How to perform the Flexion Leg Sit Up (Straight Arm)

  1. Set up. Set up in a stable, balanced starting position appropriate for the Flexion Leg Sit Up (Straight Arm) 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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