Stability Ball Russian Twist

The stability ball russian twist is a rotational core exercise in which you sit on an exercise ball holding a medicine ball or weight plate at chest height and turn your torso from one side to the other under control. The unstable base is what separates it from the floor version, since the ball rolls the moment your hips stop working, so the deep stabilizers stay switched on between reps instead of resting. The obliques do the rotating, while the glutes and adductors quietly hold the pelvis still. Speed is the usual mistake here. A two-second turn with a brief squeeze at the end of each side beats a fast set swung from the arms, and a light plate is plenty for most lifters. Ten to twelve rotations per side makes a solid working set. It fits at the end of a session, once the heavy compound lifts are finished.