title: The yips in golf: multimodal evidence for two subtypes.
abstract: OBJECTIVE
  To determine whether a model of two subtypes of yips is supported by evidence from a range of physiological, behavioral, and psychological measures.
  
  
  METHODS
  Fifteen golfers who experience yips symptoms while putting (mean age 58.1 yr, SD 13.6 yr), and nine golfers with no yips symptoms (mean age 39.6 yr, SD 19.3 yr) were recruited. Participants completed a golf history questionnaire to determine their playing experience and the nature of any yips symptoms experienced. In experiment 1, participants performed a putting task while electromyographic data were recorded from the forearm flexors and extensors and biceps brachii, bilaterally. The task was performed in two sessions, under low-pressure and high-pressure experimental conditions. The high-pressure condition was intended to increase anxiety through the use of a monetary incentive, video-taping of performance, and the presence of a confederate who provided negative feedback. Participants' state of anxiety was assessed using a questionnaire before each of the experimental sessions. In experiment 2, participants completed a task that required the inhibition of an anticipated response. Their accuracy and ability to inhibit their response was determined.
  
  
  RESULTS
  The golfers who experienced yips could be categorized according to whether they reported mainly movement-related symptoms (Type I) or anxiety-related symptoms (Type II). The Type I group exhibited greater muscle activity during putting and greater errors and less inhibition of the anticipated response task. The Type II group exhibited greater changes in cognitive anxiety and normal performance of the anticipated response task.
  
  
  CONCLUSIONS
  This study provides evidence in support of two yips subtypes. Type I is related to impaired movement initiation and execution, whereas Type II is related to performance anxiety.
authors.affiliation: Human Motor Control Laboratory, Department of Sport & Exercise Science, University of Auckland, Auckland, New Zealand. c.stinear@auckland.ac.nz
authors.forename: Cathy M
authors.initials: CM
authors.lastname: Stinear
authors.forename: James P
authors.initials: JP
authors.lastname: Coxon
authors.forename: Melanie K
authors.initials: MK
authors.lastname: Fleming
authors.forename: Vanessa K
authors.initials: VK
authors.lastname: Lim
authors.forename: Harry
authors.initials: H
authors.lastname: Prapavessis
authors.forename: Winston D
authors.initials: WD
authors.lastname: Byblow
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001007:Anxiety / Q000503:physiopathology* / Q000523:psychology; D020821:Dystonic Disorders / Q000503:physiopathology*; D004576:Electromyography; D005260:Female; D006055:Golf / Q000502:physiology* / Q000523:psychology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology; D013315:Stress, Psychological / Q000503:physiopathology / Q000523:psychology; D034941:Upper Extremity / Q000503:physiopathology