1. Keep your body stable: when lifting barbells, you need to keep your body stable so that you can give full play to your strength. You can keep your body stable by standing and sitting.
2. Breathing control: When lifting barbells, you need to control your breathing so that you can exert your strength better. Breathing can be controlled by taking a deep breath and exhaling slowly.
3. Contraction of muscles by force: When lifting barbells, you need to contract muscles by force, so as to give full play to your strength. You can help to contract your muscles by bending your knees and holding out your chest.
4. Relax properly: When lifting barbells, you also need to relax properly, so as to give full play to your strength. You can help relax by relaxing your shoulders and arms.