A warm-up is crucial before training. My warm-up consists of leg swings (as pictured below), arm swings, trunk rotations. All to just loosen up the joints and muscles around the joints. Remember, a dynamic warm-up is what you want to do as you would be able to contract the muscles while lengthening them, allowing you to get better flexibility and mobility during your workouts. Give it a try and you will notice the difference in your training.