SOPARNA provides objective data on the number of participants and their physical activity levels in targeted wilderness and natural open spaces. Trained observers record the characteristics of each individual (i.e., gender, age group, apparent race/ethnicity) and his/her physical activity level (sedentary, moderate, vigorous) and activity type using momentary time sampling. Simultaneously the observers record the contextual characteristics of the targeted areas including their accessibility, usability, and whether or not supervision, organized activities, equipment, and recreational supports are being provided.