Daily MVPA bout minutes
Among participants who engaged in at least one daily bout of MVPA, model adjusted total MVPA bout minutes/day increased across all groups from baseline (range: 16.3 to 19.6 min) to intervention (range: 22.5 to 29.5 min). The three-way Neighborhood Walkability x Reinforcement x Phase interaction was not significant. However, there was a significant Reinforcement x Phase interaction, RR = 1.18, 95% CI: 1.12, 1.24, p < .001, such that immediate reinforcement resulted in a greater increase in MVPA from baseline to intervention (+ 10.3 min/day) relative to delayed reinforcement (+ 6.3 min/day). There was also a significant Neighborhood Walkability x Phase interaction, RR = 0.987, 95% CI: 0.976, 0.997, p = .012, such that the magnitude of intervention effect (increase in daily MVPA duration) was greatest for those living in low walkable neighborhoods and declined as walkability increased: +9.3 min/day for 5th percentile, + 8.7 min/day for 25th percentile, + 8.2 min/day for 50th percentile, + 7.8 min/day for 75th percentile, + 7.0 min/day for 95th percentile. This progressive increase in daily MVPA duration for higher walkable neighborhoods is shown in the right column of Fig. 