Many people do not meet the recommended levels of physical activity. Strategies are needed to improve motivation for increasing and sustaining physical activity levels. Gamification of smartphone apps involves using game design elements including storytelling, avatars, collection of points and mastery of challenges which aim to increase intrinsic motivation of behaviours, such as physical activity. This systematic review aimed to estimate the effects of standalone gamified smartphone app-delivered interventions compared to a control group (for randomised controlled trials (RCTs)) or pre-post measures (for single-group studies) on physical activity in people of any age and any health status.
Guided by a registered protocol, 5 databases (including Web of Science, Scopus and PubMed) were used to search for RCTs and pre-post single-group studies published in English between 2008 (when literature on gamification was first published) to August 31st 2021. Eligible studies included participants of any age and health status. The interventions were gamified smartphone apps for physical activity that did not involve additional interventions or support. For RCTs, comparator groups varied and included usual care/waitlist control, diet, physical activity trackers (e.g., Calorific, Fitbit), apps (e.g., WeChat Sports) or lifestyle counselling. Indicators of physical activity was the outcome of interest (e.g., moderate-to-vigorous physical activity, step counts). Studies involving exergames, video games or serious games were excluded.
Title, abstract, and full-text screening for eligibility, and data extraction were performed by two authors independently, with disagreements resolved by a third author. The Cochrane Risk of Bias (RoB-2) and the Risk of Bias in Non-randomised Studies of Interventions (ROBINS-I) tools were used to assess the methodological quality of RCTs and single-group studies, respectively. A meta-analysis pooled the trials using standardised mean differences (SMD, based on Hedge’s g) to summarise and compare between-group (RCTs only) and within-group differences (pre-post measures of all intervention groups). A meta-regression was performed for sex (% female) and intervention duration. Subgroup analyses explored the effect of study population, age group, study design, physical activity measures (subjective/objective) and type of comparator on indicators of physical activity. Sensitivity analyses were conducted to investigate the effect of heterogeneity and risk of bias on the meta-analysis. Evidence quality was evaluated using the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach.
Nineteen studies, 17 RCTs and 2 pre-post single-group studies, involving 1,908 participants were included in the systematic review. Fifteen studies included adults and 17 studies were based on healthy cohorts. Commonly used gamification features were in-game rewards, virtual teams, points/scores and leader boards/rankings. Social support, behaviour comparison, and imaginary rewards were the most frequently implemented behaviour change techniques. The intervention duration was a median of seven weeks (range 1-24 weeks). Thirteen studies measured physical activity objectively, 2 used questionnaires and 4 used combined methods. 15 studies were rated as having ‘some concerns’ in terms of study quality which was due to deviations from the intended interventions and outcome measurement.
Sixteen studies were included in the meta-analysis. In between-group comparisons, moderate level evidence demonstrated small-to-moderate size effects supporting the use of apps to increase physical activity (n=12 apps, SMD 0.34; 95% CI 0.06 to 0.62, I2=72%). In within-group comparisons, very low level evidence demonstrated small-to-moderate size effects supporting the use of apps to increase physical activity (n=18 apps, SMD 0.38; 95% CI 0.17 to 0.59, I2=74%). Only in the between-group comparisons, both increased intervention duration (n=12 apps, SMD 0.05; 95% CI 0.01, 0.08) and being male (n=12, SMD -0.01 [female]; 95% CI -0.02 to -0.00) had a small but significant modifying effect on the intervention. Between-group subgroup analyses showed larger effects for patients (SMD 1.63; 95% CI -0.5, 3.31) compared to healthy populations (SMD 0.18; 95% CI 0.0 to 0.35). In within-group subgroup analyses, there was a moderate-to-large effect of apps on step counts (n=8, SMD 0.69; 95% CI 0.24 to 1.15), but small-to-moderate effect on moderate-to-vigorous physical activity (n=10, SMD 0.18; 95% CI 0.05 to 0.31).
Very low to moderate level evidence suggests that standalone gamified smartphone apps have small-to-moderate positive effects on physical activity levels in people of all health statuses and ages, compared to usual care/waitlist control, diet, physical activity trackers, non-gamified apps or lifestyle counselling. Findings support the use of digital health technologies to improve physical activity. Future research is required to determine which intervention features are effective in maintaining behaviour change.
Yang Y, Hu H, Koenigstorfer J. Effects of Gamified Smartphone Applications on Physical Activity: A Systematic Review and Meta-Analysis. Am J Prev Med. 2022 Apr;62(4):602-613. doi: 10.1016/j.amepre.2021.10.005. Epub 2021 Dec 7. PMID: 34893387.
