ArticleJMIR formative research2026
Digital Nudges Among New Gym Members: Controlled Formative Evaluation of Gym Attendance, Exercise Self-Efficacy, Habit Strength, and Exercise Adherence.
Article in JMIR formative research, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Background: Digital nudging strategies are increasingly implemented to promote physical activity; yet, evidence from real-world fitness settings remains limited. The early membership period in fitness centers is characterized by high dropout rates, emphasizing the need for formative evaluations that clarify behavioral mechanisms underlying exercise engagement. Objective: This study aimed to evaluate the formative impact of WhatsApp (Meta Platforms, Inc)-based digital nudges on objectively measured weekly gym visits among new fitness club members and to examine behavioral determinants associated with exercise engagement. Methods: This controlled intervention study used a 2-parallel-group design with quasi-random individual allocation conducted separately within 2 fitness clubs. The complete-case sample comprised 61 new gym members (mean age 29.05, SD 8.06 years; 21/61, 34.4% female), including 27 participants in the intervention group and 34 in the control group. During the 3-week intervention period, participants in the intervention group received brief digital nudges through designated WhatsApp groups. The messages were developed according to the Easy, Attractive, Social, and Timely (EAST) framework. Participants in the control group received no nudge messages. Gym visits were recorded electronically over 12 weeks through the fitness clubs' computerized entry systems. Self-reported measures included exercise self-efficacy, habit strength, and exercise adherence. Statistical analyses included descriptive statistics, longitudinal analysis of weekly gym attendance using generalized estimating equations (GEE), correlation analyses, and exploratory regression analysis. Results: Longitudinal GEE analysis showed a significant decline in weekly gym attendance over time (b=-0.074, SE 0.016; Conclusions: Weekly gym attendance declined significantly over the 12-week follow-up period, but the rate of decline did not differ significantly between the intervention and control groups. However, exercise adherence, exercise self-efficacy, and exercise habit strength were positively associated with more frequent attendance, and participants attending at least twice weekly reported greater self-efficacy and stronger exercise habits. These exploratory findings identify potentially relevant behavioral factors for future adherence interventions.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.