Investigating the Role of the Environment on Physical Activity Interventions (the InSPACE Project): Protocol for a Pooled Secondary Analysis of Randomized Controlled Trials

Abstract

Background: Physical activity (PA) interventions can increase levels of PA to help participants meet recommended levels. The impact of PA interventions may be affected by an individual's neighborhood environment, including attributes such as walkability, crime rates, or greenspace availability, but research to date has lacked the power and geographic spread to adequately assess the role of the environment.

Objective: The Interventions Supporting Physical Activity and the Environment (InSPACE) study used the Automatic Context Measurement Tool (ACMT) to gather environmental measures for participants around their home address in completed lifestyle intervention trials across the United States, then pooled and harmonized demographic and device-based activity data, creating a dataset for use in assessing the moderation effect of neighborhood attributes on interventions to increase PA.

Methods: PA intervention trials were recruited from across the United States, and trialists were instructed in the use of the ACMT to geocode and collect prespecified environmental measures. The InSPACE research team gathered deidentified data from trialists, including demographics, raw accelerometry data, and ACMT-generated environmental measures and harmonized data to create a pooled dataset of PA intervention trial participants.

Results: As of August 2025, a total of 39 PA intervention trials have been recruited and data from 31 of these trials have been processed and harmonized, creating a current pooled dataset of 4471 participants with any harmonized data, of whom 4360 (97.5%) have linked environmental data and 2208 (49.4%) have specified (3 days of at least 8 hours per day) accelerometry data for both baseline and postintervention. Results from the primary analysis for the InSPACE project are expected to be published in late 2026.

Conclusions: InSPACE will contribute to understanding the role of the environment in moderating the effect of interventions to increase PA. The protocols and processes of InSPACE can inform future projects in pooled data harmonization and analysis.

Keywords: accelerometry; built environment; interventions; physical activity; physical activity intervention; pooled analysis; social environment.