Why certain athletes, mostly men, get the yips is a mystery [source: Crace]. The condition generally comes on late in an athlete's career, although others, such as musicians, dentists (Ouch!) and surgeons (Oh, my!), can suffer, too. There are no warning signs, no symptoms. One day the yips appear, and in many cases, they never leave [source: Collins].
The yips are involuntary jerks, twitches or spasms that wreak havoc on a person's fine motor skills. Tasks that a person has performed hundreds, if not thousands of times, suddenly become chores. Although the problem manifests itself physically, most people suspect the yips have psychological underpinnings relating to stress and feelings of anxiety.
A few years ago, psychologists at the University of Texas looked at the free-throw percentage of NBA players in the final minutes of games when their teams were behind by a point. For three seasons, researchers charted the players' free throws during these high-stress situations. They found that when the pressure was on, the players shot worse than their career free-throw percentage [source: Beilock].
Some researchers say the yips might have a physical genesis, too, a form of dystonia, a neurological disorder that causes the involuntary contraction of muscles. Dystonia results in twisting and repetitive movements. The condition can affect just one muscle, a group of muscles or all of the body's muscles. Scientists have linked dystonia to the abnormal function of the basal ganglia, a part of the brain associated with involuntary movement. In fact, Aynsley Smith at the Mayo Sports Medicine Center in Rochester, Minn., concluded that one type of yip is a form of dystonia, while a second type occurs when a person thinks and worries too much about completing a task [source: Beilock].
On the other hand, Dr. Charles D. Adler, a Mayo Clinic neurologist, concluded in 2011 that the yips, at least in a small group of golfers he studied, were brought on by a movement disorder instead of stress or anxiety. Adler studied 25 golfers who claimed to be suffering from the yips, and compared them to 25 other golfers who were yip-free. Adler matched the golfers based on age, sex and golf handicap. Adler asked all the golfers to putt from varying lengths while he measured the electrical activity in their muscles with two specialized devices, including one called the CyberGlove II.
Adler found that 17 golfers — 15 of whom complained of the yips — exhibited signs of involuntary muscle contractions of their wrist, hands and fingers. He called the twitches and spasms "golfers' cramp" [source: Mayo Clinic]. Adler cautioned, however, that anxiety and stress might still play an important role in the yips [source: Smith].