Mechanisms of Behavior Change for a Digital Resistance Training Intervention: A Mediation Study

Introduction/PurposeFew interventions that seek to enhance resistance training behavior examine the mechanisms through which they exert their effects. Rather, many trials focus on physiological outcomes under tightly controlled training regimens. Understanding how to promote resistance training in everyday life is vital. This study aimed to examine the mediators of a remote-based 9-wk randomized controlled trial with a 4-wk self-regulation intervention period.MethodsSixty-one participants 18-35 yr of age who were not currently achieving the American College of Sports Medicine resistance training guidelines received two Zoom-based personal training sessions, resistance training equipment, and access to a Web site with training videos. After the two personal training sessions, participants were randomized to an intervention or comparison condition. Participants in the intervention condition received four weekly Zoom-based coaching calls to discuss barriers and solutions to resistance training participation. Resistance training behavior participation, self-efficacy, intention, behavioral expectations, and coping planning were assessed after the intervention period and at a follow-up 4 wk later. A mediation analysis was conducted to examine if the intervention had indirect effects on behavior through changes in any of the measured psychological variables.ResultsAll necessary measures were completed by 96.7% of participants. After the intervention, direct effects were observed on self-efficacy (b = 0.68, standard error (SE) = 0.26, P = 0.01), intention (b = 0.77, SE = 0.27, P = 0.004), coping planning (b = 0.43, SE = 0.13, P = 0.001), and behavioral expectations (b = 19.7, SE = 5.3, P = 0.0001). Self-efficacy (b = 2.07, SE = 0.83, P = 0.01) and intention (b = 3.0, SE = 0.61, P = 0.0001) had direct effects on behavior. In the multiple mediation model, intention emerged as a significant mediator (b = 2.64, SE = 0.83, P = 0.001).ConclusionThese findings suggest that changes in intention contributed to changes in behavior. Techniques that target behavioral intention may be appropriate for in-home strength-training interventions in young adults.