Malcolm Gladwell’s 10,000 Hours showed that experts spent 10,000 hours before reaching mastery level. But is that really all it takes to become a pro tennis player? The answer is not so simple. Since Gladwell’s publication, other research has pointed out you must also practice deliberately, train out of your comfort zone, and get immediate feedback. Talent is not even a factor in mastery — it’s the four pillars of training that get you to reach a high level for your tennis game.

Anders Ericsson published Peak and gave everyone clarity on what the top coaches already knew: you must practice deliberately. Ericsson did empirical research and investigated and surveyed top performing athletes, musicians, and academics to boil down the essential training characteristics. No matter your field, achieving great skills comes down to investing time in training with purpose. What does that mean for a tennis player? A tennis player must know his or her weaknesses and show up at training with the intention of improving at least one aspect of their game.

The mind must be geared toward improving with each shot and it must know what it’s trying to accomplish. To do train deliberately, you must get feedback from a coach and train outside of your comfort zone. Your coach will see what you’re doing and provide you with feedback on why you’re making mistakes and how to hit better shots. A coach will also give you drills or objectives to learn and develop new skills. Anything that makes you learn new skills will put you outside of your comfort zone.

A trap that many players fall into is the illusion they have practiced many hours when they only spent less than half the time actually training. Suppose you’re on the court for three hours. Of those three hours, it’s likely you played for 20 to 50 percent of the allocated time. Time is often spent talking, walking, resting, picking up balls, and maybe getting distracted. If that is a habitual way to train then the student won’t have invested as much time as they have thought. It is vital to cut down unnecessary interruptions to make the most of your training sessions.

In summary, you need to spend quality time training by getting feedback, training deliberately and outside of your comfort zone. And you need to do all this often over many years.