A scoping review of how automation, self-tracking dose characteristics, and participant age are operationalized in digital physical activity interventions

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Background: Self-tracking physical activity can involve receiving behavioral feedback from a device, engaging in manual self-monitoring, or a combination of the two. Objective: This scoping review examines the implementation of digital self-tracking interventions aimed at promoting physical activity among adults, emphasizing automation formats, dosage metrics, and age-specific adaptations. Methods: A scoping review was conducted of randomized intervention studies published between 2007 and 2025. Eligible studies examined digital self-tracking interventions targeting physical activity in adult populations. Data were charted to summarize intervention characteristics, including self-tracking format, automation level, intervention duration, tracking frequency, and age-related patterns. Results: A total of 197 studies involving 38,492 participants were included. Semi-automated approaches were used most frequently (52%), followed by automated (31%) and manual (7%) methods, and multiple-method approaches (10%). Wearable devices were the most common intervention format (37%), often combined with other digital applications (33%). Intervention duration averaged 21 weeks, and daily self-tracking was the most frequently reported tracking schedule (60%). Few age-related differences in self-tracking format and frequency were observed; however, interventions targeting younger adults tended to be shorter in duration, whereas those targeting middle-aged and older adults more often involved extended self-tracking periods. Conclusions: Digital self-tracking interventions for physical activity in adults show substantial variability in format and dosage. The findings highlight the need for age-responsive and dosage-specific strategies to improve engagement and support physical activity behavior change.