The goal of this exercise is to challenge muscular endurance and isometric strength in the rectus abdomens, internal/external obliques and lumbar spinal extensors, as well as seated balance, core stabilization, pelvic and shoulder girdle stabilization.

Contact Points

Lift only one leg into the v-sit position (keeping the other foot on the floor) to make the exercise easier. Hold the arms up in front of the body and rotate them tight the torso for more balance challenge.

Visual Affect

Keep the eyes straight forward and the head lifted to assist with balance. Let the gaze move in the same direction that the torso is rotating for more balance challenge.

External Stimulus

Place a weighted fitness ball between the knees or hold a fitness ball and counter rotate in the opposite direction of the legs for more balance challenge.


Hold the torso stationary and move only the legs for less challenge. Add arm movement, such as lifting both arms overhead between each rotation for more balance challenge.

Set-up and alignment

Sit with the hips centered directly on top of the dome. Flex the knees approximately 90 degrees and rest the toes lightly on the floor. Place the hands on the sides of the dome for balance assistance. Lean back slightly, while maintaining neutral posture in the lumbar spine.


Slowly lift the legs off the floor until the knees are close to chest level and the lower legs are near parallel to the floor. Keeping the thighs close together, tilt the legs to one side and counter rotate the rotate the torso in the opposite direction. Pause at the movement. Then, reverse the movement and rotate to the other side. Perform 8 to 20 repetitions to fatigue, alternating sides and adjusting the reps based on overall workout time and goals.

Safety Tips

Keep the spine in neutral alignment throughout the exercise. Avoid flexing the lumbar spine. If spine flexes, due to lack of flexibility or lack of strength in the lumbar extensor group, vary the contact points and focus on correct lumbar positioning. Maintain neutral cervical alignment. Partial scapular retraction will stabilize the shoulder girdle and facilitate balance.