ruthenium red The intensity of children s activity decreased

The intensity of children׳s activity decreased after the park modifications, although the number of visitors playing in the modified parks increased. Further, children and adults visiting parks with dogs participated in less intense physical activity than those visiting parks without dogs. Elsewhere, use of dog-exercise areas has been associated with lower ruthenium red expenditure in humans (Floyd, Spengler, Maddock, Gobster & Suau, 2008). These findings have potential health implications as higher intensity physical activity can confer additional health benefits (Janssen & Leblanc, 2010; Warburton, Nicol & Bredin, 2006). Thus, people visiting off-leash areas with dogs may be more inclined to remain stationary than in settings where dogs are only allowed on-leash. Nevertheless, the stationary activity of dog-walkers and non-dog-walkers in parks might be compensated by the health benefits gained through social interactions with other park users (Umberson & Montez, 2010; Graham & Glover, 2014), and the experience of nature within the park (Bowler et al., 2010; Lee and Maheswaran, 2010; Francis et al., 2012). Based on evidence elsewhere (Lee et al., 2009; Price, Reed, Grost, Harvey & Mantinan, 2013), the location of the parks in our study likely encouraged active transportation among most park visitors, hence contributing health benefits (Temple et al., 2011; Berrigan, Troiano, McNeel, DiSogra & Ballard-Barbash, 2006; Xu, Wen & Rissel, 2013; Pucher, Buehler, Bassett & Dannenberg, 2010). Calgary has over 150 neighbourhood and regional off-leash areas, such that the majority of households are within walking or cycling distance. Parks, including those with “off-leash” areas, need to be accessible and provide opportunities for both stationary and mobile pursuits and in proximity to households where active transportation, with or without a dog, is a convenient option. The observed proportion, but not the absolute number of children, visiting Martindale park decreased following the designation. For children, park use is positively associated with achieving recommended levels of physical activity (Edwards, Giles-Corti, Larson & Beesley, 2014). Although our methodological approach did not allow us to capture the length of time that children spend in the parks, we did find that the installation of an off-leash area was associated with children participating in less intense physical activity. In contrast, Veitch et al. (2012) found that a modification to a park, which included installation of a fenced off-leash area, resulted in an overall increase in park walking and vigorous-intensity physical activity. However, because the park upgrades in that study included additional modifications (e.g., installation of playground, walking track) the extent to which the new off-leash area, specifically, influenced changes in park behaviour is unknown. Speculatively, the decrease in the intensity of children׳s park activity might reflect safety concerns among parents and/or children regarding off-leash dogs (e.g., dog-bites, dog-chases). Perceived risks associated with interactions with unattended off-leash dogs can modify behaviours such as walking and cycling (Loukaitou-Sideris, 2006), although hypothalamus should be noted that bites in children occur most often in the home environment involving the family dog (Gilchrist, Sacks, White & Kresnow, 2008). Park policies and programming should address the issue of safety for all visitors, particularly when off-leash dogs are present in shared public space and of multi-use parks like those included in our study. Our natural experiment design allowed monitoring of park activity and use before and after physical environment modification, but the extent to which the same individuals visited the parks in 2011 and 2012 could not be determined. We captured change in park activity within one-year of the designation and modification but it is possible that changes to the park׳s environment take a longer time to influence behaviour. Our protocol of collecting data on one weekday and one weekend on two occasions may not have represented typical visiting and activity patterns in the parks and did not allow us to consider weather as an influence on park visits (Temple et al., 2011). Difference-in-difference analysis, often undertaken in natural experiments to estimate the intervention or exposure effect, assumes that the groups (exposed and unexposed) are comparable or similar with regard to the extraneous factors that may affect the outcome of interest (Meyer, 1995; Craig et al., 2012). As described elsewhere (McCormack et al., 2014), the parks in our study differed with regard to their baseline characteristics (activities, visitor characteristics, and sociodemographic profile of surrounding neighbourhood), which could modify the extent to which park modifications influence use. In addition, the civic consultation process that occurred to determine whether an area was designated as on or off-leash might have indirectly influenced patterns of park use, independent of any changes to the built environment. For instance, we found an increase in the intensity of park activities in West Hillhurst and decrease in intensity of park activities in Meadowlark among children despite neither park being designated as off-leash nor undergoing any other modifications prior to follow-up. Due to these and other unknown threats to internal validity, we used a simple analysis (i.e., one-group pre-post design for each park) and we refrained from making any between-park comparisons at follow-up. Overall, we remain cautious about whether built-environment modifications within the parks entirely explain the changes that we observed in visitation and activity patterns.