Biofeedback and digitalized motivational interviewing to increase daily physical activity: Series of factorial N-of-1 randomized controlled trials piloting the Precious app

Nurmi, Johanna, Knittle, Keegan, Naughton, Felix, Sutton, Stephen, Ginchev, Todor, Khattak, Fida, Castellano-Tejedor, Carmina, Lusilla-Palacios, Pilar, Ravaja, Niklas and Haukkala, Ari (2023) Biofeedback and digitalized motivational interviewing to increase daily physical activity: Series of factorial N-of-1 randomized controlled trials piloting the Precious app. JMIR Formative Research, 7. ISSN 2561-326X

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Background: Insufficient physical activity is a public health concern. New technologies may improve physical activity levels and enable the identification of its predictors with high accuracy. The Precious smartphone app was developed to investigate the effect of specific modular intervention elements on physical activity and examine theory-based predictors within individuals. Objective: This study pilot-tested a fully automated factorial N-of-1 randomized controlled trial (RCT) with the Precious app and examined whether digitalized motivational interviewing (dMI) and heart rate variability–based biofeedback features increased objectively recorded steps. The secondary aim was to assess whether daily self-efficacy and motivation predicted within-person variability in daily steps. Methods: In total, 15 adults recruited from newspaper advertisements participated in a 40-day factorial N-of-1 RCT. They installed 2 study apps on their phones: one to receive intervention elements and one to collect ecological momentary assessment (EMA) data on self-efficacy, motivation, perceived barriers, pain, and illness. Steps were tracked using Xiaomi Mi Band activity bracelets. The factorial design included seven 2-day biofeedback interventions with a Firstbeat Bodyguard 2 (Firstbeat Technologies Ltd) heart rate variability sensor, seven 2-day dMI interventions, a wash-out day after each intervention, and 11 control days. EMA questions were sent twice per day. The effects of self-efficacy, motivation, and the interventions on subsequent steps were analyzed using within-person dynamic regression models and aggregated data using longitudinal multilevel modeling (level 1: daily observations; level 2: participants). The analyses were adjusted for covariates (ie, within- and between-person perceived barriers, pain or illness, time trends, and recurring events). Results: All participants completed the study, and adherence to activity bracelets and EMA measurements was high. The implementation of the factorial design was successful, with the dMI features used, on average, 5.1 (SD 1.0) times of the 7 available interventions. Biofeedback interventions were used, on average, 5.7 (SD 1.4) times out of 7, although 3 participants used this feature a day later than suggested and 1 did not use it at all. Neither within- nor between-person analyses revealed significant intervention effects on step counts. Self-efficacy predicted steps in 27% (4/15) of the participants. Motivation predicted steps in 20% (3/15) of the participants. Aggregated data showed significant group-level effects of day-level self-efficacy (B=0.462; P<.001), motivation (B=0.390; P<.001), and pain or illness (B=−1524; P<.001) on daily steps. Conclusions: The automated factorial N-of-1 trial with the Precious app was mostly feasible and acceptable, especially the automated delivery of the dMI components, whereas self-conducted biofeedback measurements were more difficult to time correctly. The findings suggest that changes in self-efficacy and motivation may have same-day effects on physical activity, but the effects vary across individuals. This study provides recommendations based on the lessons learned on the implementation of factorial N-of-1 RCTs.

Item Type: Article
Additional Information: Data Availability: The data sets generated and analyzed during this study are available from the Open Science Framework [see reference 91]. Funding information: The research leading to these results has received funding from the European Community Seventh Framework Programme for the Precious project under grant agreement 611366, the Doctoral Programme in Social Sciences of the University of Helsinki, the KAUTE Foundation, and the Yrjö Jahnsson Foundation.
Uncontrolled Keywords: activity bracelet,activity tracker,automated,behavior change,biofeedback,daily steps,digitalized,ecological momentary assessment,intensive longitudinal multilevel modeling,intervention,mobile phone,motivational interviewing,n-of-1,self-efficacy,self-regulation,smartphone,within-person design,health informatics,medicine (miscellaneous),sdg 3 - good health and well-being ,/dk/atira/pure/subjectarea/asjc/2700/2718
Faculty \ School: Faculty of Medicine and Health Sciences > School of Health Sciences
UEA Research Groups: Faculty of Medicine and Health Sciences > Research Centres > Norwich Institute for Healthy Aging
Faculty of Medicine and Health Sciences > Research Centres > Lifespan Health
Faculty of Medicine and Health Sciences > Research Groups > Behavioural and Implementation Science
Faculty of Medicine and Health Sciences > Research Groups > Health Promotion
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Depositing User: LivePure Connector
Date Deposited: 17 Jan 2024 01:36
Last Modified: 24 Jan 2024 01:35
DOI: 10.2196/34232


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