Believe it or not, you don’t get fast during practice. Practice is where you might see your times improving, but your adaptation to training (i.e. getting faster) actually occurs while your body is at rest. Workout is the stimulus that causes this to happen.
不管你相不相信,游泳训练时是不会取得速度上的提高的。你在训练中看到的只是时间上的提高,对训练的适应(游得更快,也就是水平的提高,就是适应体现之一)是发生在你休息(进行营养补充)的时候。锻炼是促使这一切发生的诱因。