"I retired because I had a knee injury, my cartilage was wearing out, it was painful and I couldn't put in the four hours of practice each day that I needed to"

In this quote, Guy Forget is discussing the reason for his retirement from expert tennis. He specifies that he had a knee injury, specifically a wearing out of his cartilage. This injury triggered him a lot of pain and made it hard for him to continue practicing for the 4 hours a day that was essential for him to keep his level of ability. This reveals the physical toll that expert sports can handle a professional athlete's body and the value of having the ability to regularly train and practice in order to complete at the greatest level. Forget's retirement serves as a reminder of the sacrifices and obstacles that featured being an expert athlete.