Thrusters, also called barbell thrusters, are a great CrossFit exercise that works many muscle groups at once. First, learn the move with a dowel or unloaded barbell so you can perfect your form before adding weight. The move involves combining a deep barbell squat with an overhead press in one fluid motion. You’ll use your momentum to lift the bar over your head. To improve, gradually add weights to the barbell and perfect your form.