Your Russian Twists / Torso Twists are NOT doing you any good if you’re MOVING the weight around! When you start moving the weight around as you twist, you start to use more “arms” than actually working your core AND your legs will try to counter the movement and flop around, too. If you want to REALLY get the most out of this exercise, you need to GLUE the weight onto your upper chest. Stick it there, and don’t let it move. Then, while holding your legs as steady as you can, slowly twist as FAR