TETSU45° Side Bend vs Otis Up
The 45° Side Bend and the Otis Up both train the abs as their primary muscle. The 45° Side Bend is bodyweight-only while the Otis Up adds external weight to a bodyweight pattern. Here is how they compare and when to pick each.
Side-by-side comparison
| 45° Side Bend | Otis Up | |
|---|---|---|
| Primary muscle | abs | abs |
| Body part | waist | waist |
| Supporting muscles | obliques | hip flexors and lower back |
| Equipment | bodyweight | added weight |
| Steps in our guide | 5 | 5 |
How each one starts
45° Side Bend — first steps
- Stand with your feet shoulder-width apart and your arms extended straight down by your sides.
- Keeping your back straight and your core engaged, slowly bend your torso to one side, lowering your hand towards your knee.
Otis 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.
Full step-by-step guides are linked below.
Which should you choose?
The 45° Side Bend needs no equipment and scales through leverage, tempo and reps. The Otis Up 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 45° Side Bend better than the Otis Up?
Neither is universally better — both train the abs as the primary mover. The 45° Side Bend needs no equipment and scales through leverage, tempo and reps, while the Otis Up 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 45° Side Bend and the Otis Up 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 45° Side Bend and the Otis Up work the same muscles?
The primary muscle is the same: the abs. Supporting muscles differ slightly — obliques for the 45° Side Bend versus hip flexors and lower back for the Otis Up.
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.