The ability of the Theories of Reasoned Action (TRA) and Planned Behavior (TPB) to predict adherence to training in a group of athletes (N = 46; M age = 20.2, SD = 3.7 years) who had recently been introduced to a new strength and conditioning training regimen was investigated. Hierarchical multiple regression analyses indicated that the TPB was superior to the TRA in predicting training behavior and accounted for 24 per cent of variance in adherence to training (F(2, 43) = 8.20, p <.01) with perceived behavioral control contributing independently. Perceived behavioral control appeared to be more important in determining adherence in early stages of training. These results suggest that the TPB and TRA offer theoretical frameworks to examine adherence to new training regimens, and that they may be used to direct interventions to increase training adherence. © 2007 International Association of Applied Psychology.