Validation of the SOPLAY direct observation tool with an objective accelerometry-based physical activity monitor

The System for Observing Play and Leisure Activities (SOPLAY) is a direct observation instrument designed to facilitate observation of groups and environmental contexts. To date, no field-based studies have been done to test validity of SOPLAY using objective criteria. Purpose: The purpose of this study was to test the validity of the SOPLAY with corresponding data from an accelerometry-based activity monitor (Biotrainer pro) in a sample of 9-12 years old children. Methods: Data was collected from 19 different physical activity sessions with a total of 160 children (mean age 10.5y0.8). The SOPLAY direct observation tool and activity monitors were used to evaluate the activity levels of the groups on two different occasions. The agreement between instruments and the influence of SOPLAY sampling rate on its validity were tested. The primary outcome measure for all comparisons was the percent of youth categorized as being active but different measures were used to reflect this variable. One measure (MVPA1) used the sum of walking + very active to reflect activity while another measure (MVPA2) was based on the percentage of youth coded as very active . Results: Difference between observed and recorded activity levels varied depending on what coding was used. There were large and significant differences when the standard scoring system was used for interpreting the SOPLAY (MVPA1: 50.55y26.41%, p-value\u3c0.001). There was an overall better agreement (non-significant, p-value\u3e0.01) when the alternative measure was used (MVPA2: 1.33y22.06%). The combination of walking and very active was found to have good correspondence when compared with a parallel measure from the accelerometer based on the sum of light and moderate to vigorous activity (MVPA3: -2.02y29.00%). Correlations for the different MVPA classifications followed the same pattern (MVPA1: 0.404, MVPA2: 0.562, MVPA3: 0.575). Evaluation of the impact of scan rate on validity was evaluated by comparing agreement with different number of scans. Although observation scans every 2, 4, 6, 8, 12 and 20 had systematic increases in error, there was a substantial absolute error (21.76%) associated when there was only 1 scan per session (20 minutes scans). Conclusions: Observations provide valid indicators of MVPA if coding is based on the percentage of youth classified as very active . The results demonstrate that more frequent scans can improve the validity of the estimations

Validation and calibration of self-report methods: the Youth Activity Profile

The development of more accurate and precise methods of assessing physical activity behavior is an important public health research priority. Objective monitoring devices have advantages but the high cost and burden of data processing make them impractical for large scale applications. Subjective (survey-based) tools are inexpensive and easy to use but these suffer from questionable validity. Objective measures are often used to validate less accurate measures such as subjective instruments but this does not directly improve the accuracy or precision of the self-report instrument. The proposed line of research developed and tested a calibration equation approach that enabled data from a self-report instrument to be linked to, and scaled from, data from an objective monitoring device. This line of research was developed in a series of three studies and culminated with the development and calibration of a new self-report tool: the Youth Activity Profile. This work provides good evidence that the utility of self-report tools can be improved. Minutes of activity can be directly obtained from these tools if researchers select adequate calibration procedures. To our knowledge the Youth Activity Profile is the first self-report instrument designed to facilitate recall in youth while providing detailed information about activity patterns during important periods of the week (e.g., school time, home, weekend)

Moderating influences of baseline activity levels in school physical activity programming for children: the Ready for Recess project

Background: A limitation of traditional outcome studies from behavioral interventions is the lack of attention given to evaluating the influence of moderating variables. This study examined possible moderation effect of baseline activity levels on physical activity change as a result of the Ready for Recess intervention. Methods: Ready for Recess (August 2009-September 2010) was a controlled trial with twelve schools randomly assigned to one of four conditions: control group, staff supervision, equipment availability, and the combination of staff supervision and equipment availability. A total of 393 children (181 boys and 212 girls) from grades 3 through 6 (8–11 years old) were asked to wear an Actigraph monitor during school time on 4–5 days of the week. Assessments were conducted at baseline (before intervention) and post intervention (after intervention). Results: Initial MVPA moderated the effect of Staff supervision (β = −0.47%; p \u3c .05), but not Equipment alone and Staff + Equipment (p \u3e .05). Participants in the Staff condition that were 1 standard deviation (SD) below the mean for baseline MVPA (classified as “low active”) had lower MVPA levels at post-intervention when compared with their low active peers in the control condition (Mean diff = −10.8 ± 2.9%; p = .005). High active individuals (+1SD above the mean) in the Equipment treatment also had lower MVPA values at post-intervention when compared with their highly active peers in the control group (Mean diff = −9.5 ± 2.9%; p = .009). Conclusions: These results indicate that changes in MVPA levels at post-intervention were reduced in highly active participants when recess staff supervision was provided. In this study, initial MVPA moderated the effect of Staff supervision on children’s MVPA after 6 months of intervention. Staff training should include how to work with inactive youth but also how to assure that active children remain active

Impact of activity outcome and measurement instrument on estimates of youth compliance with physical activity guidelines: a cross-sectional study

Abstract Background The national physical activity guidelines (PAG) in many countries recommend that youth accumulate 60 min or more of moderate-to-vigorous physical activity (MVPA) daily (PAG-MVPA). A daily target of ≥ 11,500 steps/day has been proposed as a step count alternative to this guideline (PAG-Steps). Contemporary activity monitors are capable of estimating both MVPA and steps, but it is not clear how these units compare when used to evaluate compliance with the national PAG. The purpose of this study was to compare prevalence estimates of meeting the PAG-MVPA and PAG-Steps using two commonly used monitors, the ActiGraph (AG) and SenseWear Armband (SWA). Methods A sample of 69 children (25 girls and 44 boys) aged 9–16 years each wore a wrist-mounted AG and a SWA over a one-week period. Days with ≥10 h of wear time for both monitors were included in the analysis. Estimates of time spent in MVPA were obtained using the Crouter equation for the AG and from proprietary algorithms for the SWA. Step counts for the AG and SWA were directly obtained from the respective software. The prevalence of meeting the PAG-MVPA and PAG-Steps was compared within each monitor, using Cohen’s kappa (κ) statistic. Agreement was similarly assessed between monitors using each guideline individually. Results When assessed with the AG, the prevalence of meeting PAG was substantially higher for the PAG-MVPA (87.2 %) than for the PAG-Steps (54.2 %), with fair classification agreement (κ = 0.30) between the two guidelines. Higher prevalence rates were also observed for the PAG-MVPA (83.6 %) than for the PAG-Steps (33.8 %) when assessed using the SWA, but the prevalence rates and classification agreement (κ = 0.18) were lower than the values from the AG. Classification agreement between AG and SWA was lower for the PAG-MVPA (κ = 0.42) than for the PAG-Steps (κ = 0.55). Conclusions The results show differential patterns of compliance with the PAG-MVPA and PAG-Steps, as assessed by the AG and SWA. Additional research is needed to directly evaluate and compare findings from public health research based on different guidelines and measurement methods

Impact of activity outcome and measurement instrument on estimates of youth compliance with physical activity guidelines: a cross-sectional study.

BACKGROUND: The national physical activity guidelines (PAG) in many countries recommend that youth accumulate 60 min or more of moderate-to-vigorous physical activity (MVPA) daily (PAG-MVPA). A daily target of ≥ 11,500 steps/day has been proposed as a step count alternative to this guideline (PAG-Steps). Contemporary activity monitors are capable of estimating both MVPA and steps, but it is not clear how these units compare when used to evaluate compliance with the national PAG. The purpose of this study was to compare prevalence estimates of meeting the PAG-MVPA and PAG-Steps using two commonly used monitors, the ActiGraph (AG) and SenseWear Armband (SWA). METHODS: A sample of 69 children (25 girls and 44 boys) aged 9-16 years each wore a wrist-mounted AG and a SWA over a one-week period. Days with ≥10 h of wear time for both monitors were included in the analysis. Estimates of time spent in MVPA were obtained using the Crouter equation for the AG and from proprietary algorithms for the SWA. Step counts for the AG and SWA were directly obtained from the respective software. The prevalence of meeting the PAG-MVPA and PAG-Steps was compared within each monitor, using Cohen's kappa (κ) statistic. Agreement was similarly assessed between monitors using each guideline individually. RESULTS: When assessed with the AG, the prevalence of meeting PAG was substantially higher for the PAG-MVPA (87.2 %) than for the PAG-Steps (54.2 %), with fair classification agreement (κ = 0.30) between the two guidelines. Higher prevalence rates were also observed for the PAG-MVPA (83.6 %) than for the PAG-Steps (33.8 %) when assessed using the SWA, but the prevalence rates and classification agreement (κ = 0.18) were lower than the values from the AG. Classification agreement between AG and SWA was lower for the PAG-MVPA (κ = 0.42) than for the PAG-Steps (κ = 0.55). CONCLUSIONS: The results show differential patterns of compliance with the PAG-MVPA and PAG-Steps, as assessed by the AG and SWA. Additional research is needed to directly evaluate and compare findings from public health research based on different guidelines and measurement methods

A Primer on the Use of Equivalence Testing for Evaluating Measurement Agreement

Purpose Statistical equivalence testing is more appropriate than conventional tests of difference to assess the validity of physical activity (PA) measures. This article presents the underlying principles of equivalence testing and gives three examples from PA and fitness assessment research. Methods The three examples illustrate different uses of equivalence tests. Example 1 uses PA data to evaluate an activity monitor’s equivalence to a known criterion. Example 2 illustrates the equivalence of two field-based measures of physical fitness with no known reference method. Example 3 uses regression to evaluate an activity monitor’s equivalence across a suite of 23 activities. Results The examples illustrate the appropriate reporting and interpretation of results from equivalence tests. In the first example, the mean criterion measure is significantly within ±15% of the mean PA monitor. The mean difference is 0.18 METs and the 90% confidence interval of −0.15 to 0.52 is inside the equivalence region of −0.65 to 0.65. In the second example, we chose to define equivalence for these two measures as a ratio of mean values between 0.98 and 1.02. The estimated ratio of mean V˙O2 values is 0.99, which is significantly (P = 0.007) inside the equivalence region. In the third example, the PA monitor is not equivalent to the criterion across the suite of activities. The estimated regression intercept and slope are −1.23 and 1.06. Neither confidence interval is within the suggested regression equivalence regions. Conclusions When the study goal is to show similarity between methods, equivalence testing is more appropriate than traditional statistical tests of differences (e.g., ANOVA and t-tests)

Non-overweight and overweight children’s physical activity during school recess

Objective: Little research has investigated children’s physical activity levels during school recess and the contribution of recess to school day physical activity levels by weight status. The aims of this study were to examine non-overweight and overweight children’s physical activity levels during school recess, and examine the contribution of recess to school day physical activity. Design: Cross-sectional. Setting: Four elementary schools located in Nebraska, United States of America (USA). Methods: Two hundred and seventeen children (99 boys, 118 girls; 47.9% overweight) wore a uni-axial accelerometer for five consecutive school days during autumn 2009. The proportion of time spent engaged in sedentary (SED), light (LPA), moderate (MPA) and vigorous (VPA) intensity physical activity during recess was determined using age-specific accelerometer thresholds. Results: Overweight children engaged in more %MPA and less %VPA than non-overweight children, respectively. No differences were found between overweight and healthy weight children’s moderateto-vigorous physical activity (MVPA). Recess contributed 16.9% and 16.3% towards non-overweight and overweight children’s school day %MVPA, respectively. Conclusion: Examining %MVPA as an outcome variable may mask differences in recess physical activity levels between non-overweight and overweight children. Future research is needed to establish why healthy weight and overweight children engage in differing levels of %MPA and %VPA during recess

Accelerometer and self-reported measures of sedentary behaviour and associations with adiposity in UK youth

This study used accelerometer and self-report measures of overall sedentary time (ST) and screen time behaviours to examine their respective associations with adiposity among UK youth. Participants (Year groups 5, 8, and 10; n=292, 148 girls) wore the SenseWear Armband Mini accelerometer for eight days and completed the Youth Activity Profile, an online report tool designed to estimate physical activity and ST.Stature, body mass and waist circumference were measured to classify adiposity outcomes (overweight/obese and central obesity). One-way between groups ANOVA and adjusted linear, logistic and multinomial logistic regression analyses were conducted. There was a significant main effect of age on total ST across the whole week (F(2, 289)=41.64, p≤0.001). ST increased monotonically across Year 5 (581.09±107.81 min·dˉ¹), 8 (671.96±112.59 min·dˉ¹) and 10 (725.80±115.20 min·dˉ¹), and all pairwise comparisons were significant at p≤0.001. A steep age-related gradient to mobile phone use was present (p≤0.001). ST was positively associated with adiposity outcomes independent of moderate-to-vigorous intensity physical activity (MVPA; p≤0.001). Engaging in >3 hours of video gaming daily was positively associated with central obesity (OR=2.12, p≤0.05) but not after adjustment for MVPA. Results further demonstrate the importance of reducing overall ST to maintain healthy weight status among UK youth

Leisure time physical activity throughout adulthood is associated with lower medicare costs : Evidence from the linked nih-aarp diet and health study cohort

Background There is limited information about the association between long-term leisure time physical activity (LTPA) participation and healthcare costs. The purpose of this study was to investigate the association LTPA over adulthood with later life healthcare costs in the USA. Methods Using Medicare claims data (between 1999 and 2008) linked to the National Institutes of Health-American Association of Retired Persons (NIH-AARP) Diet and Health Study, we examined associations between nine trajectories of physical activity participation throughout adulthood with Medicare costs. Results Compared with adults who were consistently inactive from adolescence into middle age, average annual healthcare costs were significantly lower for maintainers, adults who maintained moderate (-US$1350 (95$2009 to-US$690) or-15.9$1200 (95% CI:-US$1777 to-US$622) or-14.1% (95% CI:-20.9% to-7.3%)) and increasers, adults who increased physical activity levels in early adulthood (-US$1874 (95$2691 to-US$1057) or-22.0$824 (95% CI:-US$1580 to-US$69 or-9.7% (95% CI-18.6% to-0.8%)). For the four trajectories where physical activity decreased, the only significant difference was for adults who increased physical activity levels during early adulthood with a decline in middle age (-US$861 (95$1678 to-US$45) or-10.1% (95% CI:-19.7% to-0.5%)). Conclusion Our analyses suggest the healthcare cost burden in later life could be reduced through promotion efforts supporting physical activity participation throughout adulthood