Data analysis
Distributions for all variables of interest were examined. Descriptive statistics were calculated to summarize participant demographics, COVID-19 experiences, stress, and sleep at baseline, as well as intervention implementation. Frequencies were conducted on categorical variables and means on continuous variables. We conducted bivariate analyses to test for study group differences in demographics and behaviors of interest at baseline. Following these analyses, we considered household size as a covariate. We also examined inter-correlations between behavioral variables of interest.Repeated measures ANOVA models were conducted to test intervention effects on outcome variables of interest. The primary models incorporated all available data from the aforementioned sample of 41 participants, examining the group effect, time effect, and group-by-time interaction in predicting key outcomes (frequency of hiking, nightly sleep duration, and stress scores) and other, ancillary outcomes of interest assessed in this study (high-risk activities, low-risk activities, physical activities, and social activities). Here participants were grouped based on assigned study groups, regardless of intervention engagement. We examined the aforementioned main effects and interactions, adjusting for total household size, and conducted a priori planned contrasts, examining study group differences in least squares means for each outcome at midpoint and at post-intervention.After primary analyses, we repeated these models twice: first in the full sample of all 53 randomized participants (12 of whom did not engage with study activities after baseline) and again with engagement in the intervention, rather than assigned study group, as the predictor of interest. The latter was a post-hoc analysis, which was added after noting that only 10 intervention-group participants engaged in the hiking challenge by completing challenge hikes, and hypothesizing that impacts of this intervention might be greater with increased engagement. We confirmed completion of challenge hikes for one control group participant who found out about the challenge on their own. We considered this individual, plus the 10 intervention group participants who completed challenge hikes, as the group actively engaged in the winter hiking challenge. We examined engagement as a predictor of outcomes of interest to inform the potential of conducting a replication study designed to increase uptake of the intervention and reassess its impacts on outcomes.