The primary purpose of this study was to develop and assess an objective, contextually- rich, observation system for investigating physical activity and associated variables in community parks. Most instruments used to study physical activity have focused on individual subjects and used self-reported values.11, 12, 17
SOPARC is unlike these measures because it uses direct observation, focuses on group behavior, and its unit of analysis is a target area, not an individual. This feature is important in the study of open environments such as parks and recreation centers where individuals enter and leave areas at different times and from different locations.
We examined the feasibility and utility of SOPARC by using it in an exploratory study to investigate park area contexts and the physical activity levels and associated characteristics of park users in multi-ethnic communities. Minority populations are understudied, and we collected data in large urban community parks in a culturally and geographically diverse metropolitan area over an extended time period (36 wk). Early morning, lunchtime, afternoon, and early evening observation periods were established in advance as the time periods with the most potential for observing diverse people using the parks. We included gender, age, and ethnicity/race groupings in the coding, because these are important factors associated with equity issues and the allocation of public resources.
Overall, the eight parks had numerous physical activity areas (total = 165 areas) which were accessible and usable most of the time (approximately 90%). Nonetheless, these areas were frequently vacant (57% of the time), and when occupied the people in them were most often sedentary (66% of the time) and rarely engaged in vigorous activity (about 16% of the time). More males than females visited the parks, and similar to results of many other studies, were more physically active.
An examination of area contextual characteristics suggests that many opportunities for physical activity in the parks were being wasted. Few organized physical activities were observed, and areas were seldom supervised or had equipment accessible. The provision of more supervision, equipment, and organized activities might lead to more residents being attracted to the parks and being more physically active when there.22
Special efforts might be required to attract population segments that were under represented users of these parks, including females and seniors.11, 16, 22
Several factors need to be considered when attempting to generalize the results from these eight parks. SOPARC is based on momentary time sampling, and is similar to taking periodic snapshots of an environment. More snapshots increase the validity of the measure. In the current study, observations were limited to 7 d per park (56 total days) at four specific time periods per day. Park use and physical activity levels during other time periods might yield different results. As well, there was no way to ensure a single individual was seen only once during the 7 d. We observed community parks in Los Angeles, California during clement weather and there may be unaccounted for environmental, cultural, and political factors that restrict the generalizability of the findings. For example, the temperate climate permits physical activity to occur outdoors year round. Increased seasonal variation in other geographic locations might restrict use of specific outdoor spaces to fewer months of the year and influence park designers to build more indoor facilities and park staff to provide different activity programs.
The reliability of SOPARC was tested by comparing 472 independent observations in 125 different target areas. Interobserver agreement scores for contextual characteristics (i.e., accessibility; usability; and presence of supervision, organized activity, and equipment) of these areas all exceeded 94%. Correlations for the number of users in park areas were also very high (R = 0.99 for both females and males) and stringent methods for assessing reliability (i.e., one that required the matching of exact counts of people) produced scores over 84% for both females and males. Reliabilities for physical activity, age, and race/ethnicity groupings also met acceptable standards. The trained assessors were familiar with the local communities, and this may have aided their categorization of park users by ethnicity/race.
Because SOPARC examines group behavior in target areas, reliability calculations for user-related variables rely upon comparing aggregate scores made by independent observers during a specific time period. Assessors are trained to enter data efficiently while using similar speed to scan areas (approximately one person per second), however, they viewed a target area from a slightly different location/angle. This aspect is most critical in measuring the physical activity in recreation settings because activity levels of individuals change rapidly from moment to moment and is not possible to ensure both assessors observe the same person at exactly the same second.
SOPARC is unable to assess for duration of physical activity, and having only three broad categories for activity levels is a limitation that does not permit a detailed analysis of activity intensities. The activity codes were previously supported by heart rate monitoring in children and adolescents,23, 24
and will permit energy expenditure rates to be estimated for target areas occupied by younger populations. The activity codes have yet to be validated in adult populations. SOPARC, however, codes both the activity levels of individuals (i.e., sedentary, walking, and vigorous) and how many people in each target area are engaged in up to three specific activity modes (e.g., soccer, cheerleading). Thus it is possible to establish estimates of energy expenditure using METS-based scoring from a standard compendium27, 28
in two different ways (i.e., via observed activity levels or observed activity modes). Using observed activity levels (e.g., sedentary, 1.5 METS; walking, 3 METS; vigorous, 6 METS) is the more conservative approach because it accounts for people in an area or sport that may be minimally active (e.g., goal keepers in soccer are frequently sedentary).
Systematic observation is labor-intensive. Assessors need to be trained on all variables, and they need to visit target areas and practice coding in them before data collection begins. Even with extensive training, there is a limit to the amount of data an assessor can record simultaneously. We were interested in numerous variables (e.g., gender, age, and ethnicity/race of park users) in addition to physical activity. In a single visual sweep it was not possible for an assessor to score all the characteristics of interest for each individual occupant of a target area while using a mechanical recorder. We tried many different protocols (including speaking codes into a digital recorder), before settling on making sequential and independent sweeps of each area for females and for males for age/ethnicity and activity level groupings. Subsequently, we were able to tie physical activity data to gender, but not to age and ethnic/race groupings. Because individuals may have entered or left an area between visual sweeps or may have been obscured behind others when it was crowded, data from separate sweeps did not always match precisely. For example, we collected gender, ethnic/race, and age data on 16,244 park users and gender and activity data on 16,048 users and (98.8% congruence, overall). Technological developments in lightweight portable electronic devices may soon solve many of these problems.
The rising prevalence of child and adult obesity14, 15
multiple health problems associated with sedentary living,1, 3
and high proportion of people of all ages not meeting health-related physical activity guidelines1–3
support the need to develop and study interventions to increase leisure-time physical activity in multiple environments. These include park and recreation settings, which are available in most communities and may be the only physical activity environments available to people of all ages and at minimal costs. Systematic observation provides more contextually-rich information about settings in which physical activity occurs than any other measure.20
SOPARC has potential for both practitioners and researchers interested in assessing the numbers and the characteristics of participants who use park and recreation settings. While the present study evaluated urban community parks, the instrument can be used in a wide range of indoor and outdoor settings including school campuses. A strength of SOPARC is that simultaneous evaluations of physical activity and associated social and physical contextual factors allow for examining the influence of setting variables on attendance and physical activity levels. Thus, it has the potential to assess the effects of environmental and policy interventions that are needed to increase the physical activity of specific populations.4
In summary, SOPARC can be used to collect relevant physical activity and contextual data in parks, and trained observers use the system reliably. Its reliability, utility, and generalizability were established through its use in generating data in numerous activity areas in large parks in diverse multi-ethnic communities. The instrument will permit data on contextual characteristics of both park areas and area users to be compared over time or across settings (e.g., for intervention evaluation purposes), and it should be useful to park designers and program planners in making formative, process, and outcome evaluations.