TETSU3/4 Sit-Up vs Weighted Side Bend (On Stability Ball)
The 3/4 Sit-Up and the Weighted Side Bend (On Stability Ball) both train the abs as their primary muscle. The 3/4 Sit-Up is bodyweight-only while the Weighted Side Bend (On Stability Ball) adds external weight to a bodyweight pattern. Here is how they compare and when to pick each.
Side-by-side comparison
| 3/4 Sit-Up | Weighted Side Bend (On Stability Ball) | |
|---|---|---|
| Primary muscle | abs | abs |
| Body part | waist | waist |
| Supporting muscles | hip flexors and lower back | obliques and lower back |
| Equipment | bodyweight | added weight |
| 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.
Weighted Side Bend (On Stability Ball) — first steps
- Sit on a stability ball with your feet shoulder-width apart and flat on the ground.
- Hold a weight in one hand and place your other hand on your hip.
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 Weighted Side Bend (On Stability Ball) adds external load to a bodyweight pattern for direct overload. 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 Weighted Side Bend (On Stability Ball)?
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 Weighted Side Bend (On Stability Ball) adds external load to a bodyweight pattern for direct overload. Choose based on your equipment and which movement you can progress consistently.
Can I do both the 3/4 Sit-Up and the Weighted Side Bend (On Stability Ball) 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 Weighted Side Bend (On Stability Ball) 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 and lower back for the Weighted Side Bend (On Stability Ball).
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.