Background and Objective:
In a previous trial on osteoporotic women with past vertebral fractures, we found a significant improvement of some physical performance markers after a 6 months Adapted Physical Activity (APA) program. In this study – using the Capability Opportunity Motivation behavior (COM-b) model domains - we investigated barriers and enablers to maintain APA over time in a perspective that it could aid us to monitor lasting healthy behavior changes relapses.

Methods:
The McGill Illness Narrative Interview (MINI) was chosen as qualitative tool to perform interviews. Three researchers analyzed independently the interviews by an _ad hoc_ checklist, looking for barriers and enablers to continue the APA program. A consensus was reached by checklist comparison and each factor influencing behavior was classified into one of the three COM-b model domains.

Results:
Seven out of the twenty-one women originally enrolled in the study group agreed to be interviewed. Four women were continuing APA for a fee and two reported to still practice Physical Activity (PA) on their own. Our assessment showed that: the three women who did not continue the APA program referred distance from the gym as the main obstacle (Opportunity barrier); the only woman who stopped all PA showed relevant physical limitations (Capability barrier); human and professional trainer skills were very appreciated facilitators (Opportunity and Motivation enablers); almost all reported both physical and psychological great benefits (Motivation enablers).

Conclusions:
Several internal and environmental determinants affected the APA maintaining. Their exploration allowed us identifying potential barriers to overcome and levers to work on in order to maintain healthy behaviors over time. In the future, to improve long-term adherence to PA programs, it is important to design Behavior Change Wheel model-based strategies, to be included in future trials, also in light of a continuous monitoring of overall potential lasting benefits.