Gamified Text Messaging Contingent on Device-Measured Steps: Randomized Feasibility Study of a Physical Activity Intervention for Cancer Survivors
Authors: Robertson Michael C , Lyons Elizabeth J , Liao Yue , Baum Miranda L , Basen-Engquist Karen M 
Published: September 2020

Background
Physical activity can confer diverse benefits on cancer survivors. Unfortunately, many cancer survivors are not sufficiently active. The efficacy of physical activity interventions for this population may be increased by grounding them in Self-Determination Theory (SDT). Combining game design elements with wearable technologies may be a useful and scalable approach to targeting SDT constructs to promote cancer survivors’ physical activity.

Objective
The primary aim of this study is to evaluate the feasibility and acceptability of Steps2Health, a physical activity intervention for cancer survivors. It also aims to investigate the effects of the intervention on motivation, physical activity, and step count.

Methods
We randomized 78 insufficiently active cancer survivors to an experimental or comparison group. All participants received a physical activity tracker. The experimental group participants also received a set sequence of multimedia messaging service messages that were triggered in real time by meeting predetermined cumulative step count totals. Messages presented information about a virtual journey and included photographs and vivid descriptions of locations to increase autonomous motivation. Additional messages targeted perceptions of relatedness (eg, role modeling) and competence (eg, facilitating mastery experiences). We administered pre- and postintervention surveys and conducted 15 individual interviews to evaluate the intervention. We performed directed content analysis of qualitative data and conducted mixed effects linear modeling to investigate participants’ changes in motivation, self-reported physical activity, and device-measured step counts.

Results
There was minimal loss to follow-up (3/78, 4%), the device wear rate was high (2548/3044, 83.71% of days), and technical problems with messaging based on real-time step counts were limited. Our qualitative data analysis revealed 3 overarching themes: accessibility, autonomous motivation, and relatedness. Participants successfully navigated the technological aspects and game design elements of the intervention. Participants found messages targeting autonomous motivation and competence or self-efficacy to be enjoyable and compelling, but one feasibility criterion for participant engagement (response rate to text messages) was not met. Messages targeting relatedness were less highly rated than the messages targeting autonomous motivation and competence or self-efficacy. During the intervention, both groups increased their motivation for physical activity (B=0.16; 95% CI 0.01 to 0.30; P=.04; d=0.49), and assignment to the experimental group was associated with increased self-reported leisure activity score (B=10.78; 95% CI 3.54 to 18.02; P=.005; d=0.64). The experimental group had greater increases in daily step counts over time (B=322.08; 95% CI 54.01 to 590.15; P=.02; d=0.28).

Conclusions
This study supports the feasibility of using real-time game design elements to target SDT constructs and increase cancer survivors’ physical activity. Overall, our findings support the acceptability of the Steps2Health intervention, but fostering active participant engagement and targeting relatedness may present additional challenges. Steps2Health may help cancer survivors increase their physical activity levels.