A basic principle of training is overloaded the system physically,
mentally, tactically and technically . The training stimulus or stress presented is greater than that which the individual is normally accustomed to(Comfort Zone). Otherwise there is no requirement for players to adapt and force the occurrence of this adaptation process.As physical, mental, technical and tactical  adaptation takes place, the training stimulus is more easily tolerated. To improve further, the training stimulus must be raised to a new level for a renewal of the overload principle. It is clear therefore that the training process is progressive and goes through a spiral of overload – fatigue – recovery – adaptation. If the training is progressed too quickly, ‘overtraining’ may be the result. This state is one in which performance falls rather than continues to improve.
It is very important for any coaches to understand how to push their players out of their comfort zone but recognize their each  player's panic zone.
To develop proper soccer training we have to define and recreate realistic training sessions. This means that the description of the problem must be precise. When defining the problem the coach must consider the following elements.
• What is going wrong in relation to the purpose or intentions?
• Who are the main players and which positions are involved in the problem?
• At which moment does the problem occur?
• Where on the field does the problem occur?
• What specific elements are affecting the game, the players and the circumstances? (Importance of the game, the field conditions, the weather, officiating, etc.)

After defining the problem, the objectives for the next training session must be identified. When introducing the training, it is important to make the players understand the problem so that they will take ownership of the problem. It is important to describe the problem precisely as possible in
terms of time, space and function in the game.