Purpose: Self-determination theory (SDT; Deci & Ryan, 1985) has proven to be a useful tool for investigating a wide range of health-related behaviors. Levels of self-determination are positioned on a continuum ranging from amotivation to externally regulated or highly controlled motivation, to highly self-determined intrinsic motivation. According to SDT, self-determined individuals are more likely to initiate and adhere to a target behavior, such as participating in physical activity programs, than individuals who feel that they are being controlled. Previous research has not addressed how the climate provided affects motivation, and the relationships with objective measures of fitness have not been explored. The purpose of this study was to examine the relationships among levels of self-determination, perceptions of the climate, trainers' motivational orientation, and performance on a muscular endurance fitness test. Methods: Participants included undergraduate kinesiology students enrolled in two different courses. Students enrolled in a scientific basis for exercise course (trainers; n = 75) were paired with students in a principles of conditioning course (trainees; n = 94). The trainees' levels of muscular endurance were assessed before and after a period of training using a standard sit-up test. In addition, at the end of the training period, the trainees completed the Health Care Climate Questionnaire (15 items; Williams, et al., 1996) and Exercise Self-Regulation Questionnaire (16 items; Ryan & Connell, 1989). The trainers completed the Problems in Training Questionnaire, which assessed their motivational orientation on a continuum, ranging from controlling to autonomy-supportive. Validity of the instrumentation was established in pilot studies. Data were analyzed using correlations among trainers' orientation, perceived climate, and self-determination. A multiple regression was conducted to examine how the self-determination variables influenced performance on the sit-up test. Analysis/Results: Training resulted in a 12.68% improvement in sit-ups. However, no significant relationships among climate, trainer orientation, and self-determination were noted. In predicting final fitness score, the perception of an autonomy-supportive climate emerged as a significant predictor, with the model accounting for 18.5 % of the variance (F = 4.755 (4, 84), p < 0.002). Conclusions: The absence of a relationship between trainer orientation and perceived climate suggests trainers may not have been effective in creating the type of climate they intended, thus highlighting the necessity of addressing motivation issues in educational settings. The perception of an autonomy-supportive climate, however, accounted for a significant portion of the variance in fitness scores, providing evidence that the climate does make a difference.Keyword(s): active participation, exercise/fitness/physical activity, professional preparation