Overview: Harnessing a smartphone app to promote physical activity in cancer survivorship
Cancer survivors often face ongoing physical and psychological challenges that can hinder regular physical activity (PA). In response, researchers developed WExercise, a smartphone app rooted in the Multi-Process Action Control (M-PAC) framework to promote PA among survivors. The study reporting these findings is a randomized controlled trial (RCT) conducted in Hong Kong, comparing the WExercise app to self-directed PA education with the goal of increasing PA, boosting exercise capacity, and improving cancer-specific quality of life (QoL).
Study design and participants
The trial was assessor-blinded and randomized 98 adults (≥18 years) who were at least 12 months post-treatment, with no metastasis or recurrence, and <150 minutes of moderate-to-vigorous PA per week. Participants were randomly assigned to either the WExercise intervention or a control group receiving a brief PA information sheet. The intervention included 12 lessons delivered weekly via the app, plus 2 introductory sessions, and integrated self-monitoring features such as step counts and a PA diary. The study ran from November 2022 to May 2024, with assessments at baseline, post-intervention (10 weeks later), and follow-up 12 weeks after the program ended.
Recruitment occurred through hospital outpatient clinics and community groups in Hong Kong. Eligible participants read and spoke Cantonese or Putonghua and could use a smartphone. All participants provided informed consent, and the trial followed CONSORT guidelines.
The WExercise intervention and its theoretical basis
WExercise was designed around the M-PAC framework, which emphasizes reflective, regulatory, and reflexive processes to bridge the intention-to-behavior gap. The 12 lessons targeted key determinants of PA: initial reflective processes (attitude, perceived capability, opportunity), progressive behavioral regulation (planning, self-monitoring, social support), and eventual reflexive changes (habit and identity). The app delivered content through text, images, and short videos, with reminders every few days to support ongoing engagement. Data from smartphones formed the self-monitoring backbone, while an integrated diary encouraged reflection on progress and goal attainment. The platform used for development was Pathverse, and usability testing preceded the trial to ensure the app could be used effectively by cancer survivors.
Outcomes and measurements
The trial tracked both objective and subjective PA, along with exercise capacity and QoL. Primary outcomes included:
- Objective PA: Moderate-to-vigorous physical activity (MVPA) measured by ActiGraph GT3X worn on the nondominant wrist for 7 days.
- Self-reported PA: Godin Leisure Time Exercise Questionnaire (GLTEQ).
Secondary outcomes included exercise capacity (6-minute walk test, 6MWT), cancer-specific QoL (EORTC QLQ-C30), and the M-PAC constructs (a composite measure reflecting reflective, regulatory, and reflexive processes).
Key findings
Primary outcomes showed divergent results between objective and self-reported PA. For ActiGraph-measured MVPA, the group-by-time interaction was not significant, indicating no substantial between-group difference in objectively measured MVPA at post-intervention or follow-up. In contrast, self-reported MVPA via GLTEQ increased more in the WExercise group than in controls, with significant differences at post-intervention and at the 12-week follow-up. Specifically, participants in the intervention reported an average increase of about 89 minutes per week at post-intervention and roughly 49 minutes per week at follow-up, compared with controls. The odds of meeting the 150-minute-per-week MVPA guideline were higher in the WExercise group at both time points (approximately 27% vs 6.7% at post-intervention; 25.7% vs 4.7% at follow-up).
Among secondary outcomes, the 6MWT indicated a significant improvement in the intervention group at post-intervention (roughly 25 meters more than controls), suggesting enhanced exercise capacity. QoL did not differ significantly between groups over time. Regarding the M-PAC constructs, most group-by-time interactions were non-significant, but within-group improvements emerged in several areas for the intervention: affective attitude toward PA, behavioral regulation, habit, and PA identity. The control group improved in behavioral regulation and PA identity, underscoring that both groups benefited from increased PA awareness, though the WExercise program offered additional strategies to support ongoing engagement.
Interpretation and implications for practice
The study provides nuanced evidence: a theory-based smartphone app (WExercise) can meaningfully increase self-reported PA and improve exercise capacity among cancer survivors, with sustained effects observed 12 weeks after the program ends. However, objective measures of MVPA did not show a parallel boost, highlighting ongoing challenges in translating intentions into sustained, device-detected activity. Several explanations are possible: self-reported gains may reflect perceived activity or recall biases; accelerometers may miss certain movements common in survivorship (e.g., cycling, upper-body activity); and wear-time adherence varied across time points. Despite these discrepancies, improved self-reported activity and functional capacity remain valuable indicators of health benefits and quality of life in survivorship care.
Clinically, WExercise shows promise as a scalable, low-cost intervention to supplement PA guidelines for cancer survivors. Future iterations could enhance objective-measure alignment by incorporating more diverse activity tracking, personalized feedback, and options for in-person or remotely delivered exercise sessions. Integrating counseling components or caregiver involvement might further strengthen the translation from intention to action, potentially boosting QoL outcomes in future studies.
Limitations and future directions
Limitations include a predominantly female, well-educated sample recruited from a single site, which may affect generalizability. The lack of blinding for participants and self-selection bias may influence results, and adherence to wearing activity monitors varied. Future research should examine broader, more diverse populations, explore combined interventions (e.g., face-to-face coaching plus app support), and investigate strategies to improve objective measurement concordance with self-reported PA.
Conclusion
WExercise, a theoretically grounded smartphone app, demonstrated meaningful improvements in self-reported physical activity and exercise capacity among cancer survivors, with effects persisting beyond the intervention period. While objective MVPA did not increase to a statistically detectable extent, the trial supports the potential of M-PAC–driven digital tools to promote PA in cancer survivorship and informs the design of future, more inclusive trials.
