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  3. Exercises
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  5. Core & Abs
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  7. Weighted Seated Tuck Crunch On Floor

Exercise guide

Weighted Seated Tuck Crunch On Floor

  • Intermediate
  • Compound
  • Rep-based
  • Waist

This compound core exercise targets the rectus abdominis and obliques by integrating a knee tuck with a torso crunch. The added weight increases resistance, challenging core stability and hip flexor strength simultaneously.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the Weighted Seated Tuck Crunch On Floor demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Abs
  • Obliques

Secondary

  • Erector spinae

Equipment

  • Dumbbell

Setup

  1. Sit on the floor with your knees bent and feet flat, holding a weight plate or dumbbell firmly against your chest.
  2. Lean your torso back at a 45-degree angle and lift your feet a few inches off the floor to find your balance on your sit bones.
  3. Engage your core and keep your spine neutral, avoiding any rounding of the shoulders.

How to do it

  1. Inhale and slowly extend your legs straight out in front of you while leaning your torso further back, stopping just before your lower back or feet touch the floor.
  2. Exhale forcefully as you pull your knees back toward your chest and crunch your upper body forward to meet them.
  3. Pause for one second at the peak of the contraction, squeezing your abs tightly.
  4. Return to the extended position using a controlled 2-second eccentric tempo.

Form checklist

  • Keep the weight pinned to your chest to ensure the load stays centered on the core.
  • Do not let your feet or upper back touch the floor at any point during the set.
  • Maintain a slight, natural curve in the lower back to protect the spine during extension.
  • Focus on pulling the ribcage toward the pelvis rather than just moving the legs.

Pro tips

  • Slow down the extension phase to maximize time under tension and prevent the use of momentum.
  • Visualize 'shortening' the distance between your sternum and your belly button during the crunch phase for maximum muscle fiber recruitment.

Make it harder

  • Hold the weight with arms fully extended in front of you to increase the lever arm and mechanical disadvantage.
  • Perform the exercise seated on the edge of a flat bench to allow your legs to drop below the hip line, increasing the range of motion.

Frequently asked

What muscles does the weighted seated tuck crunch on floor work?
The weighted seated tuck crunch on floor primarily targets the abs and obliques, and also works the erector spinae as secondary muscles.
What equipment do you need for the weighted seated tuck crunch on floor?
The weighted seated tuck crunch on floor uses dumbbell.
Is the weighted seated tuck crunch on floor good for beginners?
The weighted seated tuck crunch on floor is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.

Related exercises

  • 3/4 Sit-UpBeginner · abs and obliques
  • 45 Degree Bicycle Twisting CrunchIntermediate · abs and obliques
  • 45 Degree Lean Back Alternate Knee RaiseBeginner · abs and obliques
  • 45 Degrees Arms PlankIntermediate · abs, deltoids, obliques, and pectorals

Train it with Crucible Fit.

Every movement in this library is in the app with video and instructions, ready for your own sessions on the days between Crucibles. Your first Crucible is on us.

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