Russian TwistMain Muscle: Abdominals Mechanics Type: Compound Sit on the ground and place your feet under a stable surface. With your knees bent, slight lean back while keeping your torso straight. With one hand on the other, and arms straight, move your arms from one side to another. Do not pause in the middle. Focus on proper breathing and do not hold your breath. You can perform this exercise with a weight for a more intense exercise.