The stages of learning are phases that athletes experience as they progress through skills. As a coach, if you are aware of your athletes' level of readiness, you can help them advance more quickly.
Several models are used describe these learning stages. The most popular are the Gentile 2-stage model and the Fitts and Posner 3-stage model. The Gentile model takes into account the learning environment, whereas the Fitts and Posner model does not.
There is no definitive point at which an athlete transitions into any the phase, but descriptions help coaches know about where athletes are and which level of activities they are able to accomplish.
This phase, sometimes referred to as the cognitive stage, occurs when the beginning athlete is attempting to understand the basic task. Challenges include how to hold the racquet, how to place the feet, and where the boundaries are.
Beginners are not always aware of what they did wrong, nor do they know how to correct errors. They need basic, specific instruction and feedback during this phase.
At this stage the athlete understands the fundamentals of the skill and is in the process of refining the skill. They experience fewer errors and can detect some of them on their own. Performances are more consistent and learners begin to know what is relevant and what is not.
Here the athlete refines what is needed to accomplish the objective of the skill regardless of the situation. They also begin to learn how to diversify responses for open skills.
This is the last of the stages of learning. At this point the skill is well learned. The athlete performs the skill automatically without having to focus on execution. There are few errors and athletes can detect and know how to correct them. They can concentrate more on other aspects of the game.
As athletes transition from learning the goal of the skill to perfecting it, coaches can diversify instruction and practice conditions.
For closed skills, practices should be structured to match the conditions of competition. For open skills, the coach must systematically vary the conditions under which the skill is being learned and performed in preparation for competition.
Here is a video that does a good job of explaining and illustrating the phases.