Fidelity Of A Remote Exercise Intervention Exploring Changes In Gut Microbiome After Breast Cancer

PURPOSE: Remotely delivered exercise protocols have significantly increased since the COVID-19 pandemic. Measuring fidelity of such protocols is important for confirming intervention delivery as intended, thereby increasing study validity. Hence, our study purpose was to examine fidelity of a remotely delivered exercise intervention exploring changes in the gut microbiome among breast cancer survivors (BCS). METHODS: Post-primary treatment BCS were randomized to either a 10-week remotely delivered aerobic group (AG) or standard attention flexibility/toning control group (CG). Both groups completed 3 self-directed exercise (SDEx) sessions and 1 exercise consultation weekly. Fidelity was assessed within the five domains recommended by the National Institute of Health Behavior Change Consortium (design, training, delivery, receipt, and enactment). RESULTS: BCS aged 55 ± 9 years, 50 ± 34 months since diagnosis were randomized to the AG (n=13) or CG (n=11). To assess if both groups received similar staff attention (domain of study design), 98% and 100% of consultations were conducted in AG and CG, respectively. To assess provider training, all providers were exercise physiologists trained on study protocol by lead interventionist, who performed ≥ 2 direct observations on each provider. For treatment delivery, 92% and 100% of participants in AG and CG, respectively, achieved the a priori progression goal by week 10. For treatment receipt, the average weekly exercise relative dose intensity (cumulative ratio of completed to planned dose [frequency × time × heart rate]) was ≥100% and 98% for AG and CG, respectively. Also, >96% of SDEx sessions were performed in both conditions with the most common reasons for missed sessions being illness (53% and 75% for AG and CG, respectively) and busyness (40% and 25% for AG and CG, respectively). Treatment enactment was assessed by time and intensity achieved in AG (90% and 87%, respectively) and by time and repetitions achieved in CG (100%). CONCLUSIONS: Although fidelity domains are acceptable, participants in AG did not always achieve a priori goal or prescribed time and intensity in SDEx sessions. Efforts to improve these metrics are crucial to ensure study rigor.