The view that participation in sports in outdoor environments provides unique opportunities for growth and development is supported by the literature (Hattie, Marsh, Neill, & Richards, 1997). However, the list of types of outcomes previously examined are not exhaustive, and scant research has examined why or how particular changes occur (McKenzie, 2000). The present thesis identifies factors specific to outdoor sports that relate to outcomes of participation. Chapter 1 introduces and develops the theoretical framework for the present research. Chapter 2 develops and confirms the structure of informant-rated measures of coping effectiveness outcomes and confirms the structure of modified versions of existing self-report outcome measures. The measures are then utilised to examine the processes and outcomes in relation to participating in high-risk sports. Results revealed that the experience of emotion regulation and agency during participation are unique to high-risk sports (i.e., rock climbing) and provides evidence that the experience of emotion regulation and agency during rock climbing is related to the positive outcomes of participating in outdoor sports (i.e., increased self-esteem, greater sense of emotion regulation). Chapter 3 examines the role of the exercise environment in relation to the processes and outcomes of participation in outdoor sports. The pattern of results was counter to our original hypotheses, and reflects the reality of engaging in sports in outdoor environments. When individuals initially take part in outdoor sports they experience difficulties and adversity that challenges them psychologically. Chapter 4 summarises the main findings, the strengths and limitations of the thesis, and directions for future research. The results from the present thesis suggest that the experience of emotion regulation and agency during participation are mechanisms that are involved in changes in outcomes. The findings in the present thesis also highlight the psychological hardship and challenge that individuals face when initially participating in a sport in outdoor environments. It is through longer-term involvement in outdoor sports that individuals glean benefits from participating.