First in isolation, then in combination, and then they match as many factors of "game day" as possible to stress-test their skills.
Over-training wastes time, money, and increases the chances of injury. They spend millions of dollars trying to figure out how to maximize game day performance with minimal practice.
They know what to do ahead of training, during breaks, and after training to maximize how much skill is learned, how much is retained, and how much can be used automatically under stress.
And they're continually working on IMPROVING these 3 sensory skills.