Post-hoc analyses examining engagement in the intervention as the predictor
After noting that only 38.5% of participants who were randomized to the intervention group engaged in the hiking challenge by completing any challenge hikes, and hypothesizing that impacts of this intervention might be greater with increased engagement, we conducted an exploratory, post-hoc analysis comparing those who engaged in the challenge (10 in the intervention group plus the 1 control group participant who engaged in the challenge on their own) to those who did not. Overall, those engaged in the challenge had hiked significantly more often than those not engaged (F = 7.82, p < 0.01). Results were similar when examining frequency of physical activities generally: the link between engagement and physical activity frequency did not reach statistical significance overall (p = 0.06), but examination of least squares means at each time point showed a statistically significant difference by post-intervention, with more physical activity in the engaged group (p < 0.05). Engagement in the hiking challenge was not a significant predictor of the other outcomes of interest, although group differences between those engaged in the winter hiking challenge vs. the rest of the sample were in the expected direction for high-risk and low-risk activities and sleep. Most baseline variables were not significantly linked with engagement, although those who engaged in the challenge did already hike more often at baseline, highlighting that additional research was needed to understand potential impacts of engaging in this intervention.