Kettlebell · intermediate · waist
Kettlebell exercise oblique rotation exercise ball
Also called Seated oblique twist, Russian twist on a ball, Weighted trunk rotation, Stability ball Russian twist, Exercise ball Russian twist.
You sit on an exercise ball holding a kettlebell at chest height, lean back slightly and turn your torso to one side, then the other. The obliques do the turning, working in pairs across your body rather than one side at a time, with the rest of your midsection holding the lean and your shoulders carrying the bell. Turned slowly it is a loaded rotation exercise. Swung fast it becomes a balance drill with a weight in it.
How to do it
- Step oneSit on an exercise ball with your feet flat on the ground and hold a kettlebell with both hands at chest height.
- Step twoLean back slightly to engage your core and maintain a stable position on the ball.
- Step threeRotate your torso to one side, bringing the kettlebell toward your hip.
- Step fourReturn to center and rotate to the other side in a controlled manner.
- Step fiveContinue alternating sides.
What usually goes wrong
Each starts with what you would notice.
The ball rolls under you and your hips turn with the weight.
WhyYou are moving your whole body rather than rotating your torso on top of it, which is the easiest way to make a rotation exercise stop being one.
FixPlant your feet wide and press them into the floor, then turn only above the hips. Put a hand on one hipbone for a set: if it moves, you are swinging rather than rotating.
You feel each rep low in your back rather than around your sides.
WhyThe turn is happening down at your waist instead of through the upper part of your torso, which has far more rotation available to it.
FixThink about turning your ribcage and shoulders toward the wall beside you and leaving your belt line facing forward. Take the bell down a size while you are relearning where the turn comes from.
The bell swings from side to side and you are along for the ride.
WhySpeed. The weight builds momentum at the end of each rep and pulls you into the next one, so the muscles stop working against anything.
FixSlow it down and stop the bell at the end of each turn. A weight that is still travelling when the next rep starts is being carried by its own momentum rather than by your obliques, which is the thing you came for.
Most of your attention goes to not falling off the ball.
WhyYour feet are too close together or too far under you, so staying on the ball becomes the hardest part and the rotation gets whatever is left.
FixWiden your feet and walk them slightly forward until the ball feels settled. If it still dominates, do the same movement sitting on a bench or the floor. The rotation is the exercise; the ball is just the seat.
What it is for
The exercise oblique rotation with exercise ball and kettlebell is a seated rotational exercise that targets the obliques and core. Performed on an unstable ball with a kettlebell for resistance, it develops rotational strength and spinal stability simultaneously.
Questions people ask
- What muscles does this work?
- The obliques do the rotating, and they work in pairs diagonally across your body rather than one side working alone. The rest of your abs and your lower back hold the leaned-back position, and your shoulders hold the kettlebell out in front of you.
- Does doing this on an exercise ball make it more effective?
- The evidence is genuinely mixed and anyone telling you otherwise is picking a side. Some studies find more core muscle activity on an unstable surface, others find no difference and note that you produce less force. The effect seems to depend on the exercise and on the person. The ball is not the reason this works.
- Why does my lower back hurt when I twist?
- Usually because the turn is coming from your waist rather than from your upper torso, or because your hips are swinging along with the weight. Both are position problems and both are worth fixing before adding weight. If something hurts and keeps hurting, that is a question for a physiotherapist.
- How fast should you do weighted twists?
- Slower than feels natural. We could not find a study of rotation speed we could check, so take this as mechanics rather than a measurement: once the bell swings through the end of a turn, its momentum carries it into the next rep and your obliques stop working against anything. A rep where the bell stops at the end of each turn is worth several where it does not.
- Can you do this without the ball?
- Yes, and it is the same exercise. Sitting on a bench or on the floor with your heels down gives you a stable base and lets you put your attention on the rotation. Use the ball if you have one and it is comfortable, not because it is required.