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1.  Assessing the Contribution of Parks to Physical Activity using GPS and Accelerometry 
Purpose
Parks offer a free option for physical activity in many communities. How much time people spend using parks and the contribution that parks makes to their physical activity is not known. This study describes patterns of park use and physical activity among a diverse adult sample.
Methods
From five US states, 238 adults enrolled in or near 31 study parks. Participants wore a global positioning system (GPS) monitor (Qstarz BT-Q1000X) and an ActiGraph accelerometer (GT1M) concurrently for three weeks. Parks were mapped from local and national park shape files. Park visits and travel to and from the parks were derived from the objective data.
Results
Participants visited parks a median of 2.3 times/week and park visits lasted a median of 42.0 minutes. Overall, participants engaged in a median of 21.7 minutes/day of moderate activity and 0.1 minutes/day of vigorous activity, with an average of 8.2% of all moderate and 9.4% of all vigorous activity occurring within the parks. Among those with at least one park visit (n=218), counts per minute, moderate, moderate to vigorous physical activity (MVPA), number and time in MVPA bouts/day, and sedentary behavior were all higher on days when a park was visited compared to days when a park was not visited. Considering several definitions of active travel, walking or bicycling to and from the park added an additional 3.7 to 6.6 mean minutes of MVPA per park visit.
Conclusion
Parks contributed as a place and destination for physical activity, but were underutilized. One of the next steps in this line of inquiry is to understand characteristics of parks used more often as a place and destination for physical activity.
doi:10.1249/MSS.0b013e318293330e
PMCID: PMC3778115  PMID: 23531716
accelerometer; active travel; geographic information systems (GIS); global positioning systems (GPS)
2.  Physical activity and sedentary behavior patterns using accelerometry from a national sample of United States adults 
Background
This study described the patterns of accelerometer-determined physical activity and sedentary behavior among adults using a nationally representative sample from the United States.
Methods
Using 2003-2006 National Health and Nutrition Examination Survey (NHANES) data, 7931 adults at least 18 years old wore an ActiGraph accelerometer for one week, providing at least 3 days of wear for >=8 hours/day. Cutpoints defined moderate to vigorous physical activity (MVPA; >= 2020 and >=760 counts/minute), vigorous physical activity (> = 5999 counts/minute), and sedentary behavior (<100 counts/minute). Latent class analysis (LCA) was used to estimate patterns of physical activity and sedentary behavior. All estimates were weighted to reflect the United States population.
Results
For weighted percent of MVPA out of total wearing time, 5 classes were identified from least to most active: 65.3% of population (weighted mean 9.3 minutes/day), 24.9% (32.1 minutes/day), 3.2% that was low on the weekdays but much higher on the weekends (52.0 minutes/day), 5.9% (59.9 minutes/day), and 0.7% in the highest class (113.6 minutes/day). Using the lower MVPA threshold, 6 classes emerged with each class ranging in population from 1.2% to 43.6%. A vigorous activity class could not be derived due to low prevalence. For weighted percent of sedentary behavior out of total wearing time, 5 classes were identified from most to least sedentary: 6.3% of population (weighted mean 660.2 minutes/day), 25.1% (546.8 minutes/day), 37.7% (453.9 minutes/day), 24.0% (354.8 minutes/day), and 7.0% (256.3 minutes/day). Four of the classes showed generally similar results across every day of the week, with the absolute percents differing across classes. In contrast, the least sedentary class showing a marked rise in percent of time spent in sedentary behavior on the weekend (weighted mean 336.7-346.5 minutes/day) compared to weekdays (weighted mean 255.2-292.4 minutes/day).
Conclusion
The LCA models provided a data reduction process to identify patterns using minute-by-minute accelerometry data in order to explore meaningful contrasts. The models supported 5 or 6 distinct patterns for MVPA and sedentary behavior. These physical activity and sedentary behavior patterns can be used as intervention targets and as independent or dependent variables in future studies of correlates, determinants, or outcomes.
Electronic supplementary material
The online version of this article (doi:10.1186/s12966-015-0183-7) contains supplementary material, which is available to authorized users.
doi:10.1186/s12966-015-0183-7
PMCID: PMC4336769
Accelerometry; Latent class analysis; Moderate to vigorous physical activity; Surveillance; Weekend warrior
3.  Measurement Properties of a Park Use Questionnaire 
Environment and behavior  2012;45(4):526-547.
We determined the criterion validity and test-retest reliability of a brief park use questionnaire. From five US locations, 232 adults completed a brief survey four times and wore a global positioning system (GPS) monitor for three weeks. We assessed validity for park visits during the past week and during a usual week by examining agreement between frequency and duration of park visits reported in the questionnaire to the GPS monitor results. Spearman correlation coefficients (SCC) were used to measure agreement. For past week park visit frequency and duration, the SCC were 0.62–0.65 and 0.62–0.67, respectively. For usual week park visit frequency and duration, the SCC were 0.40–0.50 and 0.50–0.53, respectively. Usual park visit frequency reliability was 0.78–0.88 (percent agreement 69%–82%) and usual park visit duration was 0.75–0.84 (percent agreement 64%–73%). These results suggest that the questionnaire to assess usual and past week park use had acceptable validity and reliability.
doi:10.1177/0013916512436421
PMCID: PMC3708671  PMID: 23853386
environment; geographic information system (GIS); global positioning system (GPS); physical activity; reliability; validity
4.  Performance of the ActiGraph accelerometer using a national population-based sample of youth and adults 
BMC Research Notes  2015;8:7.
Background
Accelerometer output may be semi-continuous or continuous in nature, which has implications on discerning non-wear and defining physical activity intensity levels. This study described field-based accelerometer performance from a surveillance sample of youth and adults.
Methods
Using 2003–2006 National Health and Nutrition Examination Survey data, 4,028 youth ages 6 to 17 years and 7,931 adults age > =18 years wore an ActiGraph AM7164 accelerometer for one week, providing at least 3 days of wear for > =8 hours/day. Accelerometer performance was assessed by exploring the number of different values of accelerometer counts/minute for each participant.
Results
On average, youth participants had 1381 different counts/minute over 7 days (median 1360, interquartile range 1127–1623) and adult participants had 1101 different counts/minute over 7 days (median 1085, interquartile range 874–1313). For both youth and adults, when restricting to counts/minute between 0 to 4999, every possible value (in counts/minute) occurred at least once.
Conclusion
The field-based data confirmed that the accelerometer used in this study allowed for continuous counts/minute through which all but the most vigorous activities would usually occur.
doi:10.1186/s13104-014-0970-2
PMCID: PMC4304161  PMID: 25595702
ActiGraph; Intensity; Missingness; Non-wear; Physical activity; Sample weights; Sedentary behavior
5.  Changes in Physical Activity Among Postpartum Overweight and Obese Women: Results from the KAN-DO Study 
Women & health  2013;53(3):317-334.
Few studies have assessed physical activity at multiple time points in the postpartum period or used both self-reported and objective measures of assessment. The purpose of this study was to describe physical activity and sedentary behavior at two time points in a cohort of overweight or obese postpartum women using both self-reported and objective measures. In total, 132 women completed physical activity assessments at a median of 24 weeks postpartum and again approximately 10 months later. At both time points, women wore an Actical accelerometer for one week and completed the Kaiser Physical Activity Survey at both time points. Adjusted Poisson regression models were used to determine whether physical activity changed over time for the cohort. Overall counts per minute and moderate to vigorous physical activity increased from baseline to 10-months later, although the absolute levels were modest (median 6.9 to 8.8 minutes/day). A median of 64–71% at baseline and 63–67% at follow-up of their monitored time was sedentary. More intensive interventions are needed to help postpartum women integrate physical activity and reduce sedentary behavior.
doi:10.1080/03630242.2013.769482
PMCID: PMC3670793  PMID: 23705761
exercise; leisure activities; obesity; pregnancy; sedentary
6.  An Evaluation of Emergency Medical Services Stroke Protocols and Scene Times 
Background
Acute stroke patients require immediate medical attention. Therefore, American Stroke Association guidelines recommend that for suspected stroke cases, emergency medical services (EMS) personnel spend less than 15 minutes (min) on-scene at least 90% of the time. However, not all EMS providers include specific scene time limits in their stroke patient care protocols.
Objective
We sought to determine whether having a protocol with a specific scene time limit was associated with less time EMS spent on scene.
Methods
Stroke protocols from the 100 EMS systems in North Carolina (NC) were collected and abstracted for scene time instructions. Suspected stroke events occurring in 2009 were analyzed using data from the NC Prehospital Medical Information System. Scene time was defined as the time from EMS arrival at the scene to departure with the patient. Quantile regression was used to estimate how the 90th percentile of the scene time distribution varied by systems with protocol instructions limiting scene time, adjusting for system patient volume and metropolitan status.
Results
In 2009, 23 EMS systems in NC had no instructions regarding scene time; 73 had general instructions to minimize scene time; and 4 had a specific limit for scene time (i.e. 10 or 15 min). Among 9,723 eligible suspected stroke events, mean scene time was 15.9 min (standard deviation 6.9 min) and median scene time was 15.0 min (90th percentile 24.3 min). In adjusted quantile regression models, the estimated reduction in the 90th percentile scene time, comparing protocols with a specific time limit to no instructions, was 2.2 min (95% confidence interval 1.3, 3.1 min). The difference in 90th percentile scene time between general and absent instructions was not statistically different (0.7 min (95% confidence interval -0.1, 1.4 min)).
Conclusion
Protocols with specific scene time limits were associated with EMS crews spending less time at the scene while general instructions were not. These findings suggest EMS systems can modestly improve scene times for stroke by specifying a time limit in their protocols.
doi:10.3109/10903127.2013.825354
PMCID: PMC3973028  PMID: 24028711
emergency medical services; stroke; protocol; ambulances; transportation of patients
7.  Physical Activity Surveillance in Parks Using Direct Observation 
Introduction
Primary features of observational public health surveillance instruments are that they are valid, can reliably estimate physical activity behaviors, and are useful across diverse geographic settings and seasons by different users. Previous studies have reported the validity and reliability of Systematic Observation of Play and Recreation in Communities (SOPARC) to estimate park and user characteristics. The purpose of this investigation was to establish the use of SOPARC as a surveillance instrument and to situate the findings from the study in the context of the previous literature.
Methods
We collected data by using SOPARC for more than 3 years in 4 locations: Philadelphia, Pennsylvania; Columbus, Ohio; Chapel Hill/Durham, North Carolina; and Albuquerque, New Mexico during spring, summer, and autumn.
Results
We observed a total of 35,990 park users with an overall observer reliability of 94% (range, 85%–99%) conducted on 15% of the observations. We monitored the proportion of park users engaging in moderate-to-vigorous physical activity (MVPA) and found marginal differences in MVPA by both city and season. Park users visited parks significantly more on weekend days than weekdays and visitation rates tended to be lower during summer than spring.
Conclusion
SOPARC is a highly reliable observation instrument that can be used to collect data across diverse geographic settings and seasons by different users and has potential as a surveillance system.
doi:10.5888/pcd11.130147
PMCID: PMC3879002  PMID: 24384304
8.  Review of Self-reported Physical Activity Assessments for Pregnancy: Summary of the Evidence for Validity and Reliability 
Background
Epidemiologic studies and surveillance systems of pregnant women often rely collection of physical activity through self-report. This systematic review identified and summarized self-reported physical activity assessments with evidence for validity and reliability among pregnant women.
Methods
Peer-reviewed articles published through 2011 were included if they assessed validity and/or reliability of an interviewer- or self-administered physical activity questionnaire or diary among pregnant women.
Results
We identified 15 studies, including 12 studies that assessed questionnaires and 4 studies that assessed diaries, conducted in Australia, Finland, Norway, United Kingdom, United States, and Vietnam. For questionnaires, 92% (11/12) assessed mode, all assessed frequency and/or duration, and 58% (7/12) collected information on perceived intensity. All but one study (92%) assessed validity of the questionnaires. Questionnaires compared to objective measures (accelerometers, pedometers) ranged from slight to fair agreement, while comparison to other self-reported measures ranged from substantial to almost perfect agreement. Five studies (42%) assessed test-retest reliability of the questionnaires, ranging from substantial to almost perfect agreement. The four studies on diaries were all assessed for validity against objective measures, ranging from slight to substantial agreement.
Conclusions
Selection of valid and reliable physical activity measures that collect information on dose (type, frequency, duration, intensity) is recommended to increase precision and accuracy in detecting associations of physical activity with maternal and fetal outcomes.
doi:10.1111/j.1365-3016.2012.01311.x
PMCID: PMC3419488  PMID: 22882792
diary; measurement; physical activity; pregnancy; questionnaire; reliability; review; validity
9.  Validity of Secondary Retail Food Outlet Data 
Context
Improving access to healthy foods is a promising strategy to prevent nutrition-related chronic diseases. To characterize retail food environments and identify areas with limited retail access, researchers, government programs, and community advocates have primarily used secondary retail food outlet data sources (e.g., InfoUSA or government food registries). To advance the state of the science on measuring retail food environments, this systematic review examined the evidence for validity reported for secondary retail food outlet data sources for characterizing retail food environments.
Evidence acquisition
A literature search was conducted through December 31, 2012 to identify peer-reviewed published literature that compared secondary retail food outlet data sources to primary data sources (i.e., field observations) for accuracy of identifying the type and location of retail food outlets. Data were analyzed in 2013.
Evidence synthesis
Nineteen studies met the inclusion criteria. The evidence for validity reported varied by secondary data sources examined, primary data–gathering approaches, retail food outlets examined, and geographic and sociodemographic characteristics. More than half of the studies (53%) did not report evidence for validity by type of food outlet examined and by a particular secondary data source.
Conclusions
Researchers should strive to gather primary data but if relying on secondary data sources, InfoUSA and government food registries had higher levels of agreement than reported by other secondary data sources and may provide sufficient accuracy for exploring these associations in large study areas.
doi:10.1016/j.amepre.2013.06.009
PMCID: PMC3779346  PMID: 24050423
10.  ENERGY BALANCE IN ADOLESCENT GIRLS: THE TRIAL OF ACTIVITY FOR ADOLESCENT GIRLS COHORT 
Obesity (Silver Spring, Md.)  2013;22(3):772-780.
Objectives
To study correlates of change in BMI percentile and body fat among adolescent girls
Design and Methods
A longitudinal prospective study following 265 girls from the Trial of Activity for Adolescent Girls (TAAG) cohort measured in 8th grade and during 10 and 11th grade or 11th and 12th grade. Twice during 2009-2011 girls wore an accelerometer and completed a food frequency questionnaire and 7-day diary documenting trips and food eaten away from home and school. Physical activity, BMI, and percent body fat were objectively measured at each time point.
Results
Moderate to vigorous physical activity (MVPA) declined, but was not independently associated with changes in BMI percentile. Increased vigorous physical activity was associated with reductions in body fat. Diet was associated with both changes in BMI percentile and body fat. Girls who increased the percentage of caloric intake from snacks and desserts reduced their BMI percentile and body fat.
Conclusions
Some relationships between energy balance behaviors and BMI and body composition were counter-intuitive. While it is plausible that vigorous activity would result in reductions of body fat, until more accurate methods are devised to measure diet, the precise contribution of dietary composition to health will be difficult to assess.
doi:10.1002/oby.20536
PMCID: PMC3825824  PMID: 23804512
Obesity; physical activity; accelerometry; adolescence; diet; nutrition
11.  Walk Score® and Transit Score® and Walking in the Multi-Ethnic Study of Atherosclerosis 
Background
Walk Score® and Transit Score® are open-source measures of the neighborhood built environment to support walking (“walkability”) and access to transportation.
Purpose
To investigate associations of Street Smart Walk Score and Transit Score with self-reported transport and leisure walking using data from a large multi-city and diverse population-based sample of adults.
Methods
Data from a sample of 4552 residents of Baltimore MD; Chicago IL; Forsyth County NC; Los Angeles CA; New York NY; and St. Paul MN from the Multi-Ethnic Study of Atherosclerosis (2010–2012) were linked to Walk Score and Transit Score (collected in 2012). Logistic and linear regression models estimated ORs of not walking and mean differences in minutes walked, respectively, associated with continuous and categoric Walk Score and Transit Score. All analyses were conducted in 2012.
Results
After adjustment for site, key sociodemographic, and health variables, a higher Walk Score was associated with lower odds of not walking for transport and more minutes/week of transport walking. Compared to those in a “walker’s paradise,” lower categories of Walk Score were associated with a linear increase in odds of not transport walking and a decline in minutes of leisure walking. An increase in Transit Score was associated with lower odds of not transport walking or leisure walking, and additional minutes/week of leisure walking.
Conclusions
Walk Score and Transit Score appear to be useful as measures of walkability in analyses of neighborhood effects.
doi:10.1016/j.amepre.2013.03.018
PMCID: PMC3769092  PMID: 23867022
12.  Self-reported and Objectively Measured Physical Activity Among a Cohort of Postpartum Women: The PIN Postpartum Study 
Background
Few studies measure physical activity objectively or at multiple time points during postpartum. We describe physical activity at 3- and 12-months postpartum among a cohort of women using both self-reported and objective measures.
Methods
In total, 181 women completed the 3-month postpartum measures, and 204 women completed the 12-month postpartum measures. Participants wore an Actigraph accelerometer for one week and completed in-home interviews that included questions on physical activity. A cohort of 80 women participated at both time points. Poisson regression models were used to determine whether physical activity differed over time for the cohort.
Results
For the cohort, average counts/minute were 364 at 3-months postpartum and 394 at 12-months postpartum. At both time periods for the cohort, vigorous activity averaged 1 to 3 minutes/day, and moderate activity (NHANES cutpoints) averaged 16 minutes/day. Sedentary time averaged 9.3 hours at 3-months postpartum and 8.8 hours at 12-months postpartum, out of a 19-hour day. Average counts/minute increased and sedentary behavior declined from 3- to 12-months postpartum.
Conclusion
Interventions are needed to help women integrate more moderate to vigorous physical activity and to capitalize on the improvements in sedentary behavior that occur during postpartum.
PMCID: PMC3257811  PMID: 22232505
13.  Using Geographic Information Systems to Compare Municipal, County, and Commercial Parks Data 
Introduction
Parks are an integral part of a favorable built environment, and several studies have found a positive association between a favorable built environment and physical activity. Parks data are available to researchers from various sources; however, the accuracy of data sources in representing parks is unknown. This study compared secondary parks data obtained from a commercial vendor with data from municipal/county government records, all of which were verified by using Internet searches, telephone inquiries, or on-the-ground audits.
Methods
We studied large metropolitan areas in 3 states: North Carolina (1,837 sq mi), Maryland (1,351 sq mi), and New York (260 sq mi). We collected information on park land area (shapefiles) from municipal/county governments from 2009 through 2012 and from a commercial source in 2010.
Results
Commercial parks data did not include 31.1% (119/383, 20.3 sq mi) of North Carolina, 42.9% (187/436, 21.8 sq mi) of Maryland, and 71.7% (640/892, 13.5 sq mi) of New York parks that we found and verified from municipal/county sources. Municipal/county data did not include 15.7% (60/383, 9.9 sq mi) of North Carolina parks, 27.5% (120/436, 74.6) of Maryland parks, and 9.0% (80/892, 6.3 sq mi) of New York parks that we found and verified from commercial sources.
Conclusion
In this study, the combination of commercial and municipal/county data sources that were verified provided the most complete and accurate shapefile. The quality of secondary sources of parks data should be checked prior to use and, if needed, methods incorporated to improve the capture of parks.
doi:10.5888/pcd10.120265
PMCID: PMC3682810  PMID: 23742941
14.  Emergency Medical Services Capacity for Prehospital Stroke Care in North Carolina 
Introduction
Prior assessments of emergency medical services (EMS) stroke capacity found deficiencies in education and training, use of protocols and screening tools, and planning for the transport of patients. A 2001 survey of North Carolina EMS providers found many EMS systems lacked basic stroke services. Recent statewide efforts have sought to standardize and improve prehospital stroke care. The objective of this study was to assess EMS stroke care capacity in North Carolina and evaluate statewide changes since 2001.
Methods
In June 2012, we conducted a web-based survey on stroke education and training and stroke care practices and policies among all EMS systems in North Carolina. We used the McNemar test to assess changes from 2001 to 2012.
Results
Of 100 EMS systems in North Carolina, 98 responded to our survey. Most systems reported providing stroke education and training (95%) to EMS personnel, using a validated stroke scale or screening tool (96%), and having a hospital prenotification policy (98%). Many were suboptimal in covering basic stroke educational topics (71%), always communicating stroke screen results to the destination hospital (46%), and always using a written destination plan (49%). Among 70 EMS systems for which we had data for 2001 and 2012, we observed significant improvements in education on stroke scales or screening tools (61% to 93%, P < .001) and use of validated stroke scales or screening tools (23% to 96%, P < .001).
Conclusion
Major improvements in EMS stroke care, especially in prehospital stroke screening, have occurred in North Carolina in the past decade, whereas other practices and policies, including use of destination plans, remain in need of improvement.
doi:10.5888/pcd10.130035
PMCID: PMC3767834  PMID: 24007677
15.  A qualitative study of women’s perceptions of provider advice about diet and physical activity during pregnancy 
Patient education and counseling  2013;91(3):372-377.
OBJECTIVE
The purpose of this qualitative study was to gather insights into pregnant women’s experiences with provider advice about diet and physical activity.
METHODS
We conducted a series of 13 focus groups with a total of 58 pregnant African American, Caucasian, and Hispanic women of varying body sizes. Statements were independently coded, reduced, and then reconstructed to identify overarching themes with the assistance of ATLAS/ti software.
RESULTS
Mean gestational age at the time of the focus groups was 30 weeks. Women commonly reported overwhelming and confusing diet advice and a paucity of physical activity advice that was largely limited to walking. Many reported following advice; when advice was not followed, it was because women disagreed with it or simply did not want to do it.
CONCLUSION
Women would benefit from more clear guidance from physicians and other providers regarding dietary choices and physical activity in pregnancy.
PRACTICE IMPLICATIONS
Providers should make dietary and physical activity advice in pregnancy more clear and individualized and offer such guidance multiple times throughout pregnancy.
doi:10.1016/j.pec.2013.01.011
PMCID: PMC3683874  PMID: 23399436
16.  Assessment of Differing Definitions of Accelerometer Nonwear Time 
PMCID: PMC3321743  PMID: 19650401
motion sensors; physical activity; exercise
17.  State Policies Targeting Junk Food in Schools: Racial/Ethnic Differences in the Effect of Policy Change on Soda Consumption 
American journal of public health  2011;101(9):1769-1775.
Objectives
We estimated the association between state policy changes and adolescent soda consumption and body mass index (BMI) percentile, overall and by race/ethnicity.
Methods
We obtained data on whether states required or recommended that schools prohibit junk food in vending machines, snack bars, concession stands, and parties from the 2000 and 2006 School Health Policies and Programs Study. We used linear mixed models to estimate the association between 2000-2006 policy changes and 2007 soda consumption and BMI percentile, as reported by 90730 students in 33 states and the District of Columbia in the Youth Risk Behavior Survey, and to test for racial/ethnic differences in the associations.
Results
Policy changes targeting concession stands were associated with 0.09 fewer servings of soda per day among students (95% confidence interval [CI]=−0.17, −0.01); the association was more pronounced among non-Hispanic Blacks (0.19 fewer servings per day). Policy changes targeting parties were associated with 0.07 fewer servings per day (95% CI=−0.13, 0.00). Policy changes were not associated with BMI percentile in any group.
Conclusions
State policies targeting junk food in schools may reduce racial/ethnic disparities in adolescent soda consumption, but their impact appears to be too weak to reduce adolescent BMI percentile.
doi:10.2105/AJPH.2011.300221
PMCID: PMC3154241  PMID: 21778484
18.  Examination of Perceived Neighborhood Characteristics and Transportation on Changes in Physical Activity and Sedentary Behavior: The Trial of Activity in Adolescent Girls 
Health & place  2010;16(5):977-985.
We examined the association between perceived neighborhood characteristics and transport and 2-year changes in accelerometer-determined nonschool MET-weighted moderate to vigorous physical activity (MW-MVPA) and sedentary behavior of adolescent girls. Reporting that children do not play outdoors in their neighborhood, that their neighborhood was well lit, and that there were trails in their neighborhood were each associated with significant decreases in nonschool MW-MVPA. None of the neighborhood or transportation measures was associated with changes in nonschool sedentary behavior. Further work is needed to understand the determinants of the decline in physical activity and the increase in sedentary behavior among adolescent girls.
doi:10.1016/j.healthplace.2010.06.002
PMCID: PMC2918683  PMID: 20615746
environment; intervention; recreation; transportation; youth
19.  Using MapMyFitness to Place Physical Activity into Neighborhood Context 
It is difficult to obtain detailed information on the context of physical activity at large geographic scales, such as the entire United States, as well as over long periods of time, such as over years. MapMyFitness is a suite of interactive tools for individuals to track their workouts online or using global positioning system in their phones or other wireless trackers. This method article discusses the use of physical activity data tracked using MapMyFitness to examine patterns over space and time. An overview of MapMyFitness, including data tracked, user information, and geographic scope, is explored. We illustrate the utility of MapMyFitness data using tracked physical activity by users in Winston-Salem, NC, USA between 2006 and 2013. Types of physical activities tracked are described, as well as the percent of activities occurring in parks. Strengths of MapMyFitness data include objective data collection, low participant burden, extensive geographic scale, and longitudinal series. Limitations include generalizability, behavioral change as the result of technology use, and potential ethical considerations. MapMyFitness is a powerful tool to investigate patterns of physical activity across large geographic and temporal scales.
doi:10.3389/fpubh.2014.00019
PMCID: PMC3949289  PMID: 24653982
physical activity; GPS; quantified self; big data; recreation; parks; MapMyFitness; MapMyRun
20.  Beliefs About Exercise and Physical Activity Among Pregnant Women 
Patient education and counseling  2009;79(1):124-129.
Objective:
The objective of this study was to document self-reported beliefs about physical activity and exercise among pregnant women.
Methods:
The Pregnancy, Infection, and Nutrition (PIN3) Study asked 1306 pregnant women about beliefs regarding physical activity and exercise at 27-30 weeks' gestation.
Results:
While 78% of women agreed that most women can continue their regular exercise during pregnancy, fewer (68%) agreed that most women who never exercised could begin an exercise program during pregnancy. Most (89%) agreed that regular exercise was better than irregular exercise during pregnancy. While almost all women agreed with the benefits of light activity (98%), fewer agreed that there were benefits with moderate (73%) or vigorous exercise (13%). Differences in beliefs were most notable by educational level, race/ethnicity, and whether they participated in regular exercise during pregnancy.
Conclusion:
Future studies can better elucidate the reasons behind the differences in beliefs, to explore whether cultural reasons are contributing to these differences and whether tailored messages would be more effective than general educational approaches.
Practice Implications:
This study provides information to create more successful interventions to help women understand concepts regarding the safety and benefits of physical activity during pregnancy.
doi:10.1016/j.pec.2009.07.028
PMCID: PMC2848492  PMID: 19699603
pregnancy; exercise; recreational activity; beliefs; cohort; physical activity; recommendations
21.  PHYSICAL ACTIVITY DURING PREGNANCY AND POSTPARTUM DEPRESSIVE SYMPTOMS 
Midwifery  2012;29(2):139-147.
Objective
to examine the associations between total and domain-specific moderate-to-vigorous physical activity (MVPA) during pregnancy and postpartum depressive symptoms.
Design
a prospective cohort study.
Participants
data were obtained from 652 women recruited from prenatal clinics at University of North Carolina during 2001–2005 for the Pregnancy, Infection, and Nutrition (PIN) Postpartum Study.
Measurements
MVPA measured at 17–22 and 27–30 weeks’ gestation was investigated as a predictor of depressive symptoms assessed with the Edinburgh Postnatal Depression Scale at 3 months postpartum.
Findings
total MVPA was not associated with depressive symptoms when using either 17–22 weeks’ gestation or 27–30 weeks’ gestation MVPA measures. In general, there were minimal associations for domain-specific MVPA. The direction of associations between depressive symptoms and work, adult and child care, and outdoor household MVPAs differed by time of measurement.
Key Conclusions
the association between physical activity and postpartum depressive symptoms may differ with the timing of assessment. Additional studies (i.e. with a larger sample of women or a sample of at-risk women) following women throughout pregnancy and postpartum are needed to explore differences in the influence of physical activity on depressive symptoms.
Implications for Practice
assessment of potential risk factors for elevated depressive symptoms, such as participation levels in different types of physical activity, throughout pregnancy may assist in determining who may be susceptible to postpartum depression.
doi:10.1016/j.midw.2011.12.006
PMCID: PMC3459267  PMID: 22726573
22.  Physical activity and maternal-fetal circulation measured by Doppler ultrasound 
Objective
To examine the association of physical activity on maternal-fetal circulation measured by uterine and umbilical artery Doppler flow velocimetry waveforms.
Study Design
Participants included 781 pregnant women with Doppler ultrasounds of the uterine and umbilical artery and who self-reported past week physical activity. Linear and generalized estimating equation regression models were used to examine these associations.
Results
Moderate-to-vigorous total and recreational activity were associated with higher uterine artery pulsatility index (PI) and an increased risk of uterine artery notching as compared to reporting no total or recreational physical activity, respectively. Moderate-to-vigorous work activity was associated with lower uterine artery PI and a reduced risk of uterine artery notching as compared to no work activity. No associations were identified with the umbilical circulation measured by the resistance index.
Conclusion
In this epidemiologic study, recreational and work activity were associated with opposite effects on uterine artery PI and uterine artery notching, though associations were modest in magnitude.
doi:10.1038/jp.2012.68
PMCID: PMC3459289  PMID: 22678142
work; recreational activity; maternal-fetal blood flow; pregnancy; Doppler flow velocimetry waveforms; preeclampsia
23.  Physical Activity Beliefs, Barriers, and Enablers among Postpartum Women 
Journal of Women's Health  2009;18(12):1925-1934.
Abstract
Background and Methods
Physical activity during postpartum is both a recommended and an essential contributor to maternal health. Understanding the beliefs, barriers, and enablers regarding physical activity during the postpartum period can more effectively tailor physical activity interventions. The objective of this study was to document self-reported beliefs, barriers, and enablers to physical activity among a cohort of women queried at 3 and 12 months postpartum. Five questions about beliefs and two open-ended questions about their main barriers and enablers regarding physical activity and exercise were asked of 667 women at 3 months postpartum. Among the sample, 530 women answered the same questions about barriers and enablers to physical activity at 12 months postpartum.
Results
Agreement on all five beliefs statements was high (≥89%), indicating that women thought that exercise and physical activity were appropriate at 3 months postpartum, even if they continued to breastfeed. For the cohort, the most common barriers to physical activity at both 3 and 12 months postpartum were lack of time (47% and 51%, respectively) and issues with child care (26% and 22%, respectively). No barrier changed by more than 5% from 3 to 12 months postpartum. For the cohort, the most common enablers at 3 months postpartum were partner support (16%) and desire to feel better (14%). From 3 to 12 months postpartum, only one enabler changed by >5%; women reported baby reasons (e.g., baby older, healthier, not breastfeeding, more active) more often at 12 months than at 3 months postpartum (32% vs. 10%). Environmental/policy and organizational barriers and enablers were reported less often than intrapersonal or interpersonal barriers at both time points.
Conclusions
A number of barriers and enablers were identified for physical activity, most of which were consistent at 3 and 12 months postpartum. This study provides information to create more successful interventions to help women be physically active postpartum.
doi:10.1089/jwh.2008.1309
PMCID: PMC2828187  PMID: 20044854
24.  Farmers’ market use is associated with fruit and vegetable consumption in diverse southern rural communities 
Nutrition Journal  2014;13:1.
Background
While farmers’ markets are a potential strategy to increase access to fruits and vegetables in rural areas, more information is needed regarding use of farmers’ markets among rural residents. Thus, this study’s purpose was to examine (1) socio-demographic characteristics of participants; (2) barriers and facilitators to farmers’ market shopping in southern rural communities; and (3) associations between farmers’ market use with fruit and vegetable consumption and body mass index (BMI).
Methods
Cross-sectional surveys were conducted with a purposive sample of farmers’ market customers and a representative sample of primary household food shoppers in eastern North Carolina (NC) and the Appalachian region of Kentucky (KY). Customers were interviewed using an intercept survey instrument at farmers’ markets. Representative samples of primary food shoppers were identified via random digit dial (RDD) cellular phone and landline methods in counties that had at least one farmers’ market. All questionnaires assessed socio-demographic characteristics, food shopping patterns, barriers to and facilitators of farmers’ market shopping, fruit and vegetable consumption and self-reported height and weight. The main outcome measures were fruit and vegetable consumption and BMI. Descriptive statistics were used to examine socio-demographic characteristics, food shopping patterns, and barriers and facilitators to farmers’ market shopping. Linear regression analyses were used to examine associations between farmers’ market use with fruit and vegetable consumption and BMI, controlling for age, race, education, and gender.
Results
Among farmers’ market customers, 44% and 55% (NC and KY customers, respectively) reported shopping at a farmers’ market at least weekly, compared to 16% and 18% of NC and KY RDD respondents. Frequently reported barriers to farmers’ market shopping were market days and hours, “only come when I need something”, extreme weather, and market location. Among the KY farmers’ market customers and NC and KY RDD respondents, fruit and vegetable consumption was positively associated with use of farmers’ markets. There were no associations between use of farmers’ markets and BMI.
Conclusions
Fruit and vegetable consumption was associated with farmers’ market shopping. Thus, farmers’ markets may be a viable method to increase population-level produce consumption.
doi:10.1186/1475-2891-13-1
PMCID: PMC3896848  PMID: 24405527
Farmers’ market; Fruit and vegetable consumption; Rural communities; Obesity; Random digit dial
25.  Association between physical activity and risk of stroke subtypes: The Atherosclerosis Risk in Communities (ARIC) Study 
Neuroepidemiology  2012;40(2):109-116.
Background
The relationship between stroke subtypes and physical activity is unclear.
Methods
Using data from 13,069 men and women aged 45-64 years who participated in the Atherosclerosis Risk in Communities (ARIC) Study, physical activity was assessed by self-report using the Baecke questionnaire at baseline (1987-1989). The American Heart Association’s (AHA) ideal cardiovascular health guidelines served as basis for the calculation of three physical activity categories: poor, intermediate, and ideal. Stroke and its subtypes were ascertained from physician review of medical records. Multivariable adjusted hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox regression models.
Results
During a median follow-up of 18.8 years, a total of 648 incident ischemic strokes occurred. Significant inverse associations were found between physical activity categories and total, total ischemic, and nonlacunar stroke in adjusted models (age, sex, race-center, education, cigarette-years). Compared with poor physical activity, the adjusted HR (95% CI) for ideal physical activity were 0.78 (0.62, 0.97) for total, 0.76 (0.59, 0.96) for total ischemic, 0.85 (0.51, 1.40) for lacunar, 0.77 (0.47, 1.27) for cardioembolic, and 0.71 (0.51, 0.99) for nonlacunar stroke. Additional adjustments for waist-to-hip ratio, systolic blood pressure, antihypertensive medication, diabetes, left ventricular hypertrophy and laboratory parameters attenuated the HR. Further sex- and race-specific analysis revealed that the association was predominantly observed among males and among African-Americans.
Conclusion
These data suggest a tendency toward a reduced risk of total, total ischemic, and nonlacunar stroke with higher levels of physical activity.
doi:10.1159/000342151
PMCID: PMC3641888  PMID: 23095721
cerebrovascular disease; stroke subtypes; exercise; epidemiology; prevention

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