USA Today – Douglas Robson – May 27, 2004 – PARIS What actually happens to a player when they tighten up and lose focus? According to leading sports psychologist Jim Loehr, the body’s natural “fight or flight” response triggers an increase in an adrenal hormone called cortisol. When that biochemical change occurs, muscles tense, concentration falters, attention spans decrease and irritation crops up.

“It’s a primitive hormone designed to help you survive by freezing or by running away,” Loehr explains, “but it doesn’t help you thread the needle on that big serve or carve up the court with that brilliant drop volley. It’s the antithesis of that.”

John F. Murray, a psychologist who has helped second-round loser Vince Spadea of the USA resuscitate his career, adds that in sports such as football, players need to tense up to make a block, but if a tennis player has the same muscle-constricting response, it can be disastrous.

“It can slow your leg muscles, make your execution sluggish and affect the control of your racket,” Murray says. “Tennis is very competitive but requires calm temperament levels and fine motor skills.”

Sometimes a player can develop “yips,” a nervous twitch on a certain stroke that can last a match or over the course of a career. It visibly afflicted Gabriela Sabatini on her serve later in her career, a development some think hastened her retirement.

The same happened to Pam Shriver, one of the fiercest and most dependable servers in the game.

“It gave me the weirdest, weirdest feeling,” she says of the sudden ball-toss problems toward the end of her playing days. “It made me realize that there could be involuntary actions â€â€? miscues with my left hand toss â€â€? that I’d never considered before.”

The insecurity resulted into more serious yips that spread to her forehand and volley and made a tennis court feel like “the worst place in the world.”

“If your brain has to wrap around a lot of emotions, it’s a mess,” says Shriver, now an ESPN commentator, who didn’t turn to a sports psychologist but wishes she had.