The Russian twist increases rotational strength in the core and abdominals. The exercise also strengthens the lower back and hips.
Sit on the floor with your knees and hips bent to 90° with your feet flat on the floor, holding a weight plate with your arms fully extended in front of your chest.
Lean back so your torso is at a 45° angle, and use your abs to twist your torso as far as you can in one direction before reversing the motion and returning to the starting position to prepare to twist in the opposite direction.
Do not allow your body to sway back and forth as you twist.
Squeeze your abs as hard as possible for maximum effectiveness.
Do not sit up too high, which will place stress on your lower back.