In sport, the ability to perform under heightened levels of pressure is one of the largest differences between those who are successful and those who are not. There are a number of phenomena associated with breakdowns in an athlete’s performance in high pressure environments, collectively known as paradoxical performances (Baumeister & Showers, 1986). The two most prevalent and researched forms of paradoxical performance are the yips and choking. Although choking has been identified as playing a key role in understanding the yips, to date, no literature has explored these phenomena simultaneously. The current literature highlights potential mechanisms which may explain the yips and choking, such as the Attentional Control Theory (Eysenck & Derekshan, 2011) and the Conscious Processing Hypothesis (Masters, 1992). However, there is limited literature on the potential predictors that may increase the susceptibility of both these paradoxical performances and those which do, focus on golf. There are three aims of this thesis. The first aim was to develop a definition that best encompasses all aspects of the yips. This was achieved by conducting a systematic review of the yips literature which supported the development of a new two dimensional yips model including individuals with both focal dystonia and choking (type-III). The second aim was to investigate potential predictors associated with both the yips and choking that was achieved by completing two studies. The first explored the lived experiences of elite level archers who have experienced both choking and the yips and revealed a number of potential predictors associated with both the yips and choking. The second study tested these predictors using online questionnaires with elite level archers and golfers, and confirmed two discrete predictive models for yips and choking. The final aim of the thesis was to investigate the potential mechanisms associated with performance under pressure. A lab-based study where golfers and archers performed under both high and low pressure found that pressure elicited a range of psychological, physiological and kinematic changes in performance. The proposed two dimensional model from the systematic review received initial support for its application. A number of participants met the criteria for each of the different classifications: type-I, those who experience focal dystonia like symptoms; type-II, those who experience choking like symptoms and; type-III, those who experience both focal dystonia and choking like symptoms. This thesis also highlights the role of social predictors of the yips and choking with perfectionistic self-presentation being the most influential for those susceptible for the yips. These findings will enable practitioners to have a better understanding to effectively classify those who experience choking and the yips. This will allow practitioners to more effectively intervene with those who experience different classifications of the yips. The thesis also highlights the issues in the current literature that surround the measurement and conceptualisation of the yips type-I, type-II and type-III behaviour and provides future directions.

Brass musicians are known to experience a performance problem that is sometimes called valsalva maneuver or musical stuttering. This problem is known to cause difficulty starting a first note, tension in the throat, and tightness in the chest. Unfortunately, the research literature lacks sufficient details for evidence-based interventions. Therefore, the purpose of this study is to characterize and define this performance problem as experienced by brass musicians. An online epidemiologic survey was developed and deployed to collect data from brass musicians who have experienced this problem in their own playing. The survey was designed to acquire data in order to characterize and define the phenomenon through a biopsychosocial framework. The survey was also designed to assess whether this problem aligns with Altenmuller's heuristic model of motor control disruptions. A diverse group of brass musicians (n = 252) participated and offered relevant details for characterizing and defining this problem. Analysis of characteristic data suggests this problem is not a form of musical stuttering. Considering these data through Altenmuller's model suggests that this problem is experienced as a spectrum of motor disruptions that can develop into a unique type of musician's dystonia. While additional research is warranted, the results of this study are applicable to brass musicians, brass pedagogues, music educators, and performing arts health clinicians.