Digital Mindset Intervention for Half Marathon Performance

This randomized controlled trial evaluates whether a brief digital mindset intervention can improve performance and training outcomes among recreational runners training for a half marathon. The intervention is grounded in psychological theories of mindsets, expectation, placebo effects, and effort perception, which suggest that how individuals interpret physical symptoms during exercise-such as fatigue or muscle soreness-can influence motivation, persistence, and overall outcomes. The intervention aims to reframe mild physical symptoms experienced during training as signs of physiological adaptation rather than negative signals, helping participants develop more adaptive mindsets about effort and endurance. Intervention content includes brief digital modules that introduce the concept of meta-mindsets (beliefs about how mindsets influence experiences and outcomes) and provide applied strategies for interpreting discomfort as a normal and constructive part of the endurance training process. The digital modules are delivered over a nine-week period leading up to the participant's half marathon and are designed to be time-efficient and accessible. To ensure comparability, participants assigned to the active control group receive parallel-format digital modules that focus on widely followed training advice, without any mindset-related material. Participants in the control group do not receive digital content during the study period. All intervention content is delivered via the Intervengine platform or email. Participants are randomly assigned in a 1:1:1 ratio to one of three study arms. Randomization is conducted independently using a computer-generated allocation sequence. The study follows an intention-to-treat analysis approach, with additional per-protocol analyses among participants who complete the intervention and race. Statistical analyses will include ANOVA and mixed-model approaches to assess group differences in primary and secondary outcomes over time. Missing data will be addressed using multiple imputation techniques. All eligibility criteria, outcome measures, and intervention details are specified in the relevant sections of the clinical trial registration record. This trial contributes to a growing body of research examining scalable psychological interventions that support physical activity adherence and performance. It explores whether brief mindset-focused training can enhance endurance outcomes in real-world, non-clinical athletic contexts.