Anna Kournikova's serve became a head thing. The kind of DF #'s that she used to put up was staggering. I think I remember some people putting down money on how many DF's Anna would hit in a match.
Before her, Hana Mandlikova's serve literally disintegrated and her game around it. For a serve and volleyer, your game is really centered around your serve. She changed her service motion so much to adjust to her back injury from 1982 to 1989, and it really cost her. As King once said of her, she had changed her motion so often that she suffered breakdowns in her technique when she got tight.
Thinking back to the 1987 Amelia Island final vs. Steffi, she was mostly just putting in cream puff 2nd serves as her 1st serve. It was sad to see. By 1989 she had Anna Kournikova-like DF #'s. It was all about confidence, or a lack thereof.
In 1988, a lot of Martina's problems were centered around her serve. With that hip injury, it really affected what she was getting on the ball. Then she changed to that funky high-handed service motion. As far as her serve was concerned, her head was all over the place.
McEnroe had similar problems to Martina on his serve later in his career. Eventually people caught on to Edberg's serve too. When you're used to dominating matches with your serve, and suddenly you aren't, that starts to affect your mind.
