Russian twists are ab exercises with several variations to match up to your fitness level. If you're a beginner, you can start with the basic exercise and progress to the more difficult exercises as your abdominals get stronger. More advanced exercisers can try the harder variations but should stop immediately if they are unable to maintain proper exercise form for the Russian twist.
Basic Russian Twist
The basic Russian twist is a bodyweight exercise using just the weight of your upper torso to work your abs. The lower back muscles also work due to the position of the spine during this exercise. Unlike crunches in which your rest your back on the floor between repetitions, the Russian twist makes you hold your spine in neutral off the floor the entire time. To begin, sit with your feet on the floor and knees bent. Hold your arms straight in front of you with the fingers entwined. Lean back approximately 45 degrees, and then twist side to side from your waist.
Intermediate Russian Twist
Eventually, bodyweight exercises lose their challenge as your abs and back get stronger. To keep the Russian twist from becoming too easy, you can add weight. The easiest free weight to use is a weighted plate with handles. You can also use a standard weight plate, medicine ball or dumbbell. Sitting in the same position as the basic twist, hold the weight with your arms straight in front of you and rotate side to side. This action strengthens the oblique muscles on the sides of the abdomen.
Advanced Russian Twist
Stability ball Russian twists are appropriate for advanced exercisers, as the stability ball is much harder to lie on and keep your balance on than the floor. To perform this exercise, lie with your back on the ball, your arms straight toward the ceiling with the hands clasped and your feet on the floor. Then, twist to the left and roll your right shoulder off the ball as your hands point to the left. Repeat in the other direction. You strengthen your rectus abdominus, transverse abdominus, lower back and obliques with the stability ball Russian twist.
Standing Russian Twist
A standing Russian twist targets the obliques through rotating your spine and the abs as they work to support of the spine. Because this is a dynamic exercise in which you throw a medicine ball, it is best to have a partner to catch the ball or at least a wall to stop it. To do this variation of the Russian twist, stand with your feet shoulder-width apart and hold a medicine ball with your arms straight in front of your abdomen. Twist to the left and then twist to the right, throwing the ball.