Weighted Ball Side Bend
The weighted ball side bend has you lying on your side over an exercise ball, hips supported and feet braced, bending laterally toward the floor and then pulling back up to work your obliques through a longer range than a standing version allows. Holding a weight across your chest adds resistance to that lateral flexion, making it a more targeted way to train the sides of your core once bodyweight side bends feel easy. It suits anyone training rotational and lateral core strength for sports, carrying, or simply a stronger midsection.
Why it works
Bending sideways at the waist is the job of your obliques, the muscles that run diagonally along the sides of your abdomen, and they work hardest when your torso has room to move through a real range rather than a few inches. Resting your hips on an exercise ball supports your lower body while leaving your torso free to drop into a deeper side bend than standing on the floor allows, which lengthens your obliques further before they contract to pull you back up. Holding a weight across your chest adds resistance directly to that lateral flexion, isolating the obliques without pulling your lower back or hip flexors into the movement the way a twisting exercise might.
Set up
- Position your hips over an exercise ball, lying on your side with your feet braced against a wall or sturdy object.
- Hold a weight plate or dumbbell across your chest with both hands.
- Let your torso hang down toward the floor at the start, feeling a stretch along your side.
- Keep your hips stacked and your body in one line from shoulder to feet.
How to do it
- Bend your torso down toward the floor under control, feeling the stretch deepen along your side.
- Pause briefly at the bottom of the stretch.
- Pull your torso back up using your obliques until your spine returns to a straight line.
- Avoid rotating your torso forward or backward during the movement.
- Lower back down and repeat for the set, then switch sides.
Form cues
- Hips stay stacked, with no forward or backward rotation.
- The weight stays close to your chest, not held out away from your body.
- Movement happens purely side to side, not twisting.
- Pause at the bottom stretch before pulling back up.
Breathing: Exhale as you pull your torso back up to straight, inhale as you lower into the stretch.
Common mistakes
Letting the torso rotate forward or backward instead of staying stacked.
Fix: Keep your hips and shoulders aligned in one plane throughout; rotation shifts the work away from your obliques.
Using momentum to swing back up instead of a controlled contraction.
Fix: Slow the tempo down and pull up deliberately, treating each rep as a controlled contraction rather than a bounce.
Holding the weight too far from the body.
Fix: Keep the weight tucked against your chest; holding it out in front shifts the work away from your obliques, which isn't the point of this exercise.
Training only one side repeatedly out of habit.
Fix: Match the sets and reps on both sides so your obliques develop evenly.
How to program it
- As a light-to-moderate isolation movement for a single muscle group, 2 to 3 times a week works well for most people without risking excess fatigue.
- Two to three sets of 10 to 15 reps per side is a reasonable starting range before adding more weight.
- It fits well near the end of a core or lower body session, once your main lifts are done and you have attention left for a slower, targeted movement.
Safety notes
- Keep the range of motion within what feels like a stretch, not strain, along your side.
- If you feel the movement in your lower back rather than the side of your core, reduce the range and check that your hips stay stacked.
Exercise profile
- Force
- Pull
- Mechanics
- Isolation
- Category
- Strength
Frequently asked questions
How many reps of weighted ball side bends should I do?
Two to three sets of 10 to 15 reps per side is a solid starting point, adding weight gradually once the movement feels controlled.
What can I do without an exercise ball?
A standing dumbbell side bend trains the same lateral flexion pattern with no ball needed, and a cable side bend is a good option if you have access to a cable station.
Will this give me a smaller waist?
It strengthens and can add some shape to your obliques, but spot targeting fat loss at the waist isn't how the body works; overall body composition depends on your full training and nutrition picture.
Why do I feel this more in my lower back than my obliques?
That usually means your hips have rotated out of line or the range is too deep for your current control. Reduce the range and keep your hips and shoulders stacked throughout.