First of all, correct it, it should be said: exhale = exhale. ('shout' means' out') Inhale when practicing dumbbells, and inhale evenly; Exhale (exhale) only when the initial action is resumed. Similarly, when exhaling, the airflow is required to be uniform, and sudden exhalation is not allowed, which may suddenly relax the tense muscles and cause muscle strain. Correct breathing can effectively improve the training effect.