Russian Twists

Sit on the floor with your knees bent and feet flat, leaning back slightly to engage your core. Hold a weight, medicine ball, or just clasp your hands together in front of you. Lift your feet off the floor (optional for more challenge) and balance on your butt, keeping your back straight. Twist your torso to the right, bringing the weight or your hands beside your hip, then return to the center. Twist to the left in the same manner, alternating sides with each rep. Keep your core engaged throughout the movement and avoid letting your back round. Perform the twists in a controlled manner, focusing on rotational movement from your torso, not just your arms.