The Weighted Russian Twist (legs up) is a core strength exercise in which the feet are elevated off the floor while holding a weight plate, dumbbell, or medicine ball and rotating the torso side to side, directly targeting the obliques. The iliopsoas and quadriceps work continuously to keep the legs raised, while the rectus abdominis stabilizes the spine — making it effective for building rotational strength and core endurance.
How to do the Weighted Russian Twist (legs up)
- 1Sit on the floor with your knees bent and feet flat, holding a weight plate, dumbbell, or medicine ball in both hands at chest height.
- 2Lean your torso back to roughly a 45° angle to the floor, bracing your core to hold that position without rounding the lower back.
- 3Lift your feet off the floor so your shins are parallel to the ground, or extend your legs fully, creating a V-shape with your body.
- 4Rotate your torso to the right, guiding the weight toward the floor beside your right hip while keeping your legs still, arms slightly bent, and feet elevated.
- 5Reverse the rotation under control, bringing the weight back through center and then to the left, toward the floor beside your left hip.
- 6Continue alternating sides in a controlled rhythm, ensuring the movement comes from trunk rotation rather than swinging the arms.
- 7Complete the desired number of reps, then lower your feet to the floor in a controlled manner and sit upright before releasing the weight.
Form tips
- Keep your gaze forward and your chin slightly tucked — looking down collapses the chest and shortens your rotational range.
- Resist the weight on the return path rather than letting it swing back; the eccentric phase builds oblique strength just as much as the rotation itself.
- If your lower back rounds during the set, reduce the lean angle slightly or use a lighter weight until your core stability improves.
- Keep your shoulders away from your ears throughout — upper-trap tension restricts thoracic rotation and reduces the effectiveness of each rep.
Common mistakes
- Letting the feet drop to the floor mid-set, which removes the demand on the iliopsoas and quadriceps and significantly reduces total core engagement.
- Using momentum to swing the weight side to side rather than actively rotating the torso, which limits oblique activation and increases the risk of a lower-back strain.
- Rounding the lower back instead of maintaining a neutral spine, which shifts stress away from the obliques and onto the lumbar vertebrae.
- Allowing the arms to lead the twist instead of the torso, which isolates the shoulders and dramatically reduces the rotational load on the obliques.
- Holding the breath for the whole set, which makes the brace impossible to sustain across every rep — form usually breaks down late in the set. Exhale as you rotate to each side instead.
Frequently asked questions
What muscles does the Weighted Russian Twist (legs up) work?
The primary muscle targeted is the obliques. The iliopsoas and quadriceps work as synergists to hold the legs elevated, and the rectus abdominis stabilizes the spine throughout.
How is the legs-up Russian twist different from the standard Russian twist?
Raising the feet off the floor removes the base of support provided by the heels, forcing the iliopsoas and quadriceps to contract continuously to keep the legs elevated. This increases total core demand and makes the obliques work harder to control rotation compared to the flat-foot variation.
Is it better to do Russian twists with legs straight or knees bent?
Both work. Keeping the knees bent shortens the lever arm of the legs, reducing the load on the iliopsoas and quadriceps and making it easier to maintain the elevated position. Extending the legs increases the lever arm and demands more from the hip flexors, making the exercise more challenging.
What weight should I use for the Weighted Russian Twist (legs up)?
Start light — a 2–5 kg (5–10 lb) plate or dumbbell is appropriate for most beginners to this variation. Because the legs-up position already increases core demand, adding too much weight too soon leads to lower-back rounding. Progress the load only when you can complete all reps with a neutral spine and controlled rotation.
Can the Weighted Russian Twist (legs up) hurt my lower back?
It can if performed with poor form. The most common cause of lower-back discomfort is rounding the lumbar spine instead of hinging from the hips, or using a weight that is too heavy. Maintaining a neutral spine, bracing the rectus abdominis before each rep, and moderating load will keep the exercise safe and effective.
