TETSU3/4 Sit-Up vs Cable Kneeling Crunch
The 3/4 Sit-Up and the Cable Kneeling Crunch both train the abs as their primary muscle. The 3/4 Sit-Up is bodyweight-only while the Cable Kneeling Crunch uses a cable. Here is how they compare and when to pick each.
Side-by-side comparison
| 3/4 Sit-Up | Cable Kneeling Crunch | |
|---|---|---|
| Primary muscle | abs | abs |
| Body part | waist | waist |
| Supporting muscles | hip flexors and lower back | obliques |
| Equipment | bodyweight | cable |
| Steps in our guide | 5 | 5 |
How each one starts
3/4 Sit-Up — first steps
- 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.
Cable Kneeling Crunch — first steps
- Attach a rope handle to a high pulley and kneel down facing away from the machine.
- Hold the rope handle with both hands and place it behind your head, keeping your elbows out to the sides.
Full step-by-step guides are linked below.
Which should you choose?
The 3/4 Sit-Up needs no equipment and scales through leverage, tempo and reps. The Cable Kneeling Crunch keeps constant tension on the muscle through the whole range of motion. If your gym has both options, neither is a wrong choice: pick the one that feels strongest through a full range, and swap after 6 to 8 weeks to keep the abs adapting.
Full form guides
Common questions
Is the 3/4 Sit-Up better than the Cable Kneeling Crunch?
Neither is universally better — both train the abs as the primary mover. The 3/4 Sit-Up needs no equipment and scales through leverage, tempo and reps, while the Cable Kneeling Crunch keeps constant tension on the muscle through the whole range of motion. Choose based on your equipment and which movement you can progress consistently.
Can I do both the 3/4 Sit-Up and the Cable Kneeling Crunch in the same program?
Yes, but usually not in the same session — they overlap heavily on the abs. A common setup is one as your main movement and the other on a second training day, or alternating them block by block.
Do the 3/4 Sit-Up and the Cable Kneeling Crunch work the same muscles?
The primary muscle is the same: the abs. Supporting muscles differ slightly — hip flexors and lower back for the 3/4 Sit-Up versus obliques for the Cable Kneeling Crunch.
Track it in Tetsu
Tetsu tracks both movements separately, keeps your PRs per exercise, and tells you which one is actually progressing. Free to start.