<p>Baumeister and colleagues’ (1998) limited strength model of self-regulation was used as a framework to investigate the independent and combined effects of motivation and conservation on self-control strength depletion. Volunteer university students (<em>N</em> = 72; 23 males and 49 females) participated in the study. Participants completed two maximum endurance isometric handgrip trials separated by the Stroop colour word interference task. Participants were randomized to either a conservation or no-conservation condition before completion of the Stroop task. After performing the Stroop task the participants were then further separated into an autonomy support condition or a no autonomy support condition. It was hypothesized that participants (1) who were provided with autonomy support would perform better on the second endurance trial and report higher feelings of autonomous regulation, (2) who were in the conservation condition would perform worse on the Stroop task and better on the second endurance trial, and (3) who were provided with autonomy support and were in the conservation condition would perform the best on the second endurance trial, while those who were not provided autonomy support and did not conserve were predicted to perform the worst of any group on the second endurance trial. Autonomy support was associated with better performance on the second endurance trial but not greater feelings of autonomous regulation. Conservation was associated with poorer performance on the Stroop task, but not superior performance on the second endurance trial. There was no evidence supporting the combined effects of autonomy support and conservation. Findings support conclusions that people conserve self-control strength when anticipating future strength depletion and autonomy support helps people cope with self-control strength depletion and deliver superior performance on a muscular endurance task.</p> / Master of Science in Kinesiology