Performance psychology involves the process of facilitating the development of the skills needed by the athlete during his or her time to shine in a performance. Furthermore, the process is almost entirely tied to the events preceding the performance as they are the foundation of the desired outcome. This preparation involves not only physical, but also mental, psychological, spiritual and emotional practice. In fact, the physical aspect of a performance has much less importance than the mental and soul aspects. Tennis is a perfect example of this. No matter how much a player trains, if he gets too nervous in front of a match, his whole body will freeze and he will very easily commit unforced errors. This happened quite often at the beginning of my games until I managed to train my mind to stay focused on the game rather than winning. I also remember reading a book about tennis when I was about 8 years old and there was a question that said something like, "How technical, tactical, physical, and mental is a tennis match?" and several professional players have responded by saying that the mental part contributes to practically all of the game. At first, because I had never experienced a real, challenging encounter, I thought to myself, “No, that's not right. It's 25% each. It makes sense; it's mathematics." Looking back I realize how silly my comment was because I had no idea what a real performance was and that the physical aspect, while important, is more relevant in preparing for a match. Each performance is made up of various smaller elements that each contribute to the overall picture, just like a puzzle piece; however, each has a unique position that no other piece can fill. The variables that influence performance can be mainly classified into three main domains: active motor, affective and cognitive. Some variables are internal, while others are external. Externalities, or external factors that influence a performance, vary from situation to situation; however, they need to be addressed somehow, in order for the show to continue. The active motor domain is that which concerns the physical aspect of a performance; in tennis which refers to the practice of all existing shots; synchronize the bending of the knees with having the right angle for a swing and hitting the ball in a certain way (e.g. with topspin, flat, slice); as well as doing conditioning exercises to increase physical strength and endurance. The affective domain is the one involved in the emotional, mental and spiritual aspect of a performance. In tennis, how a player prepares in those areas depends entirely on his style. I usually use self-talk and tell myself I'm going to play great and have fun; I also completely take my mind off tennis by doing something productive like homework, for example, so that I don't think too much about the match to exhaust my mind, but I'm also doing something that requires my mind to focus on one thing. In fact, I'm writing this article right now because I have a match in 5 hours. The cognitive domain is that which concerns the neurobiological aspect of a performance, i.e. the changes that occur in the body as a consequence of other variables. To address this domain, the player must address the variable that causes the change in the body. For example, if in a game I start to feel very tense and start sweating from nervousness, I may find that instead of using positive self-talk, I was letting my mind worry about the people who were watching me instead of staying focused on playing. Biochemically, my brain sends signals to cells that.