Gaynor joined UniSA as an Associate Professor in Sport and Exercise Psychology in 2011 (relocating from the UK) and was promoted to Professor in 2019. Her early research was on anxiety and performance, during which time she worked with several international squads. More recently, Gaynor’s research has been on the evaluation of acute and chronic effects of exercise on psychological responses; methods to motivate exercise behaviour change within community and rehabilitation environments; and mechanisms associated with the affect-exercise intensity relationship. Her research has included evaluation and development of interventions for those with, or at risk of, post traumatic stress; assessment of movement behaviour in older adults and the impact of medication; the impact of exercise, and technology (including augmented and virtual reality) interventions on physical and psychological health; and the use of perceived exertion to control and quantify exercise intensity.  She has worked with able bodied and disabled groups and her research employs quantitative and qualitative methodologies to understand the mechanisms and processes integral to psychological health and exercise behaviour.