Cited by 74Mobile Health and mHealth ApplicationsDigital Mental Health InterventionsPhysical Activity and Health

Investigating intervention components and exploring states of receptivity for a smartphone app to promote physical activity: Protocol of a microrandomized trial

Open access
Kramer, Jan-Niklas, Künzler, Florian, Mishra, Varun, Presset, Bastien, Kotz, David, Smith, Shawna, Scholz, Urte, Kowatsch, Tobias·2019·JMIR Research Protocols

Published version of a preprint

Abstract

BACKGROUND: Smartphones enable the implementation of just-in-time adaptive interventions (JITAIs) that tailor the delivery of health interventions over time to user- and time-varying context characteristics. Ideally, JITAIs include effective intervention components, and delivery tailoring is based on effective moderators of intervention effects. Using machine learning techniques to infer each user's context from smartphone sensor data is a promising approach to further enhance tailoring. OBJECTIVE: The primary objective of this study is to quantify main effects, interactions, and moderators of 3 intervention components of a smartphone-based intervention for physical activity. The secondary objective is the exploration of participants' states of receptivity, that is, situations in which participants are more likely to react to intervention notifications through collection of smartphone sensor data. METHODS: In 2017, we developed the Assistant to Lift your Level of activitY (Ally), a chatbot-based mobile health intervention for increasing physical activity that utilizes incentives, planning, and self-monitoring prompts to help participants meet personalized step goals. We used a microrandomized trial design to meet the study objectives. Insurees of a large Swiss insurance company were invited to use the Ally app over a 12-day baseline and a 6-week intervention period. Upon enrollment, participants were randomly allocated to either a financial incentive, a charity incentive, or a no incentive condition. Over the course of the intervention period, participants were repeatedly randomized on a daily basis to either receive prompts that support self-monitoring or not and on a weekly basis to receive 1 of 2 planning interventions or no planning. Participants completed a Web-based questionnaire at baseline and postintervention follow-up. RESULTS: Data collection was completed in January 2018. In total, 274 insurees (mean age 41.73 years; 57.7% [158/274] female) enrolled in the study and installed the Ally app on their smartphones. Main reasons for declining participation were having an incompatible smartphone (37/191, 19.4%) and collection of sensor data (35/191, 18.3%). Step data are available for 227 (82.8%, 227/274) participants, and smartphone sensor data are available for 247 (90.1%, 247/274) participants. CONCLUSIONS: This study describes the evidence-based development of a JITAI for increasing physical activity. If components prove to be efficacious, they will be included in a revised version of the app that offers scalable promotion of physical activity at low cost. TRIAL REGISTRATION: ClinicalTrials.gov NCT03384550; https://clinicaltrials.gov/ct2/show/NCT03384550 (Archived by WebCite at http://www.webcitation.org/74IgCiK3d). INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/11540.

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Authors
Kramer, J.-N., Künzler, F., Mishra, V., Presset, B., Kotz, D., Smith, S., Scholz, U., & Kowatsch, T.
Affiliations
  • University of St.Gallen (CH)
  • ETH Zurich (CH)
  • Dartmouth College (US)
  • University of Lausanne (CH)
  • University of Michigan (US)
  • University of Zurich (CH)
Corresponding author
Kramer, Jan-Niklas
Venue
JMIR Research Protocols
Published
2019-01-31
Volume
8
Issue
1
Pages
e11540
ISSN
1929-0748 (ISSN-L)
OpenAlex
W2898978558
Cited by
74
References
69
Citations by year
2026: 6 · 2025: 7 · 2024: 8 · 2023: 3 · 2022: 10 · 2021: 13 · 2020: 17 · 2019: 10
FWCI
15.27
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • JMIR Research Protocols (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Zurich Open Repository and Archive (University of Zurich) (acceptedVersion, cc-by-nc)
  • Repository for Publications and Research Data (ETH Zurich) (submittedVersion, cc-by)
  • Alexandria (UniSG) (University of St.Gallen) (submittedVersion)
  • Zurich Open Repository and Archive (University of Zurich) (submittedVersion, cc-by-nc)
  • ETH Zürich Research Collection (cc-by)
  • Zurich Open Repository and Archive (University of Zurich)
Topics
  • Health Sciences › Health Professions › General Health Professions › Mobile Health and mHealth Applications
  • Social Sciences › Psychology › Applied Psychology › Digital Mental Health Interventions
  • Health Sciences › Medicine › Physiology › Physical Activity and Health
Keywords
physical activity promotion, just-in-time adaptive interventions, smartphone-based intervention, chatbots, mobile health, financial incentives, planning, step goals, smartphone sensor data, intervention moderators, insurance company employees, health behavior change

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