Athletes, coaches, and sport psychologists remain focused on exploring psychological strategies which can yield effective coping, and maintain or improve performance when under pressure. Most approaches to enhance performance (under pressure) continue to be designed with the intention of either altering the content of internal experiences (i.e. thoughts, feelings and physical sensations) or regulating attention toward the important components of skill execution. Our unique and contemporary programme of research seeks to develop and evaluate the efficacy and/or effectiveness of an Acceptance and Commitment Therapy (ACT) based intervention(s), designed to enhance the quality of the competitive experience in athletes - with a focus on reducing ‘choking' and maximising performance under pressure. Specifically, our research will assess the impact of core ACT processes and test the predictions made by underpinning theory (ie Relational Frame Theory, RFT) on established mechanisms that contribute to skill breakdown.