Direct Observation is a Valid Criterion for Estimating Physical Activity and Sedentary Behavior

2014 ◽  
Vol 11 (4) ◽  
pp. 860-863 ◽  
Author(s):  
Kate Lyden ◽  
Natalia Petruski ◽  
Stephanie Mix ◽  
John Staudenmayer ◽  
Patty Freedson
Keyword(s):  
Physical Activity ◽  
Sedentary Behavior ◽  
Direct Observation ◽  
Absolute Intensity ◽  
Criterion Measure ◽  
Free Living ◽  
Activity Intensity ◽  
Measurement Tools ◽  
Trained Observers ◽  
Valid Criterion

Background:Physical activity and sedentary behavior measurement tools need to be validated in free-living settings. Direct observation (DO) may be an appropriate criterion for these studies. However, it is not known if trained observers can correctly judge the absolute intensity of free-living activities.Purpose:To compare DO estimates of total MET-hours and time in activity intensity categories to a criterion measure from indirect calorimetry (IC).Methods:Fifteen participants were directly observed on three separate days for two hours each day. During this time participants wore an Oxycon Mobile indirect calorimeter and performed any activity of their choice within the reception area of the wireless metabolic equipment. Participants were provided with a desk for sedentary activities (writing, reading, computer use) and had access to exercise equipment (treadmill, bike).Results:DO accurately and precisely estimated MET-hours [% bias (95% CI) = –12.7% (–16.4, –7.3), ICC = 0.98], time in low intensity activity [% bias (95% CI) = 2.1% (1.1, 3.2), ICC = 1.00] and time in moderate to vigorous intensity activity [% bias (95% CI) –4.9% (–7.4, –2.5), ICC = 1.00].Conclusion:This study provides evidence that DO can be used as a criterion measure of absolute intensity in free-living validation studies.

Cross-Validation of Two Accelerometers for Assessment of Physical Activity and Sedentary Time in Preschool Children

2017 ◽  
Vol 29 (2) ◽  
pp. 268-277 ◽  
Author(s):  
Sofiya Alhassan ◽  
John R. Sirard ◽  
Laura B. F. Kurdziel ◽  
Samantha Merrigan ◽  
Cory Greever ◽  
...  
Keyword(s):  
Physical Activity ◽  
Mixed Model ◽  
Criterion Measure ◽  
Free Living ◽  
Type Method ◽  
Individual Level ◽  
Cut Point ◽  
Activity Intensity ◽  
The Individual ◽  
Low Sensitivity

Purpose:The purpose of this study was to cross-validate previously developed Actiwatch (AW; Ekblom et al. 2012) and AcitGraph (AG; Sirard et al. 2005; AG-P, Pate et al. 2006) cut-point equations to categorize free-living physical activity (PA) of preschoolers using direct observation (DO) as the criterion measure. A secondary aim was to compare output from the AW and the AG from previously developed equations.Methods:Participants’ (n = 33; age = 4.4 ± 0.8 yrs; females, n=12) PA was directly observed for three 10-min periods during the preschool-day while wearing the AW (nondominant wrist) and AG (waist). Device specific cut-points were used to reduce the AW-E (Ekblom et al. 2012) and AG (AG-S, Sirard et al. 2005; AG-P, Pate et al. 2006) data into intensity categories. Spearman correlations (rsp) and agreement statistics were used to assess associations between the DO intensity categories and device data. Mixed model regression was used to identify differences in times spent in activity intensity categories.Results:There was a significant correlation between AW and AG output across all data (rsp = 0.41, p < .0001) and both were associated with the DO intensity categories (AW: rsp = 0.47, AG: rsp = 0.47; p < .001). At the individual level, all devices demonstrated relatively low sensitivity but higher specificity. At the group level, AW-E and AG-P provided similar estimates of time spent in moderate-to-vigorous PA (MVPA, AW-E: 4.7 ± 4.1, AG-P: 4.4 ± 3.3), compared with DO (5.1 ± 3.5). Conclusion: The AW-E and AG-P estimated times spent in MVPA were similar to DO, but the weak agreement statistics indicate that neither device cut-point equations provided accurate estimates at the individual level.

Validity and Comparability of a Wrist-Worn Accelerometer in Children

2012 ◽  
Vol 9 (3) ◽  
pp. 389-393 ◽  
Author(s):  
Orjan Ekblom ◽  
Gisela Nyberg ◽  
Elin Ekblom Bak ◽  
Ulf Ekelund ◽  
Claude Marcus
Keyword(s):  
Physical Activity ◽  
Energy Expenditure ◽  
Roc Analysis ◽  
Living Condition ◽  
Criterion Measure ◽  
Physical Activity Intensity ◽  
Free Living ◽  
Activity Intensity ◽  
Mechanical Shaker

Background:Wrist-worn accelerometers may provide an alternative to hip-worn monitors for assessing physical activity as they are easier to wear and may thus facilitate long-term recordings. The current study aimed at a) assessing the validity of the Actiwatch (wrist-worn) for estimating energy expenditure, b) determining cut-off values for light, moderate, and vigorous activities, c) studying the comparability between the Actiwatch and the Actigraph (hip-worn), and d) assessing reliability.Methods:For validity, indirect calorimetry was used as criterion measure. ROC-analyses were applied to identify cut-off values. Comparability was tested by simultaneously wearing of the 2 accelerometers during free-living condition. Reliability was tested in a mechanical shaker.Results:All-over correlation between accelerometer output and energy expenditure were found to be 0.80 (P < .001).Based on ROC-analysis, cut-off values for 1.5, 3, and 6 METs were found to be 80, 262, and 406 counts per 15 s, respectively. Energy expenditure estimates differed between the Actiwatch and the Actigraph (P < .05). The intra- and interinstrument coefficient of variation of the Actiwatch ranged between 0.72% and 8.4%.Conclusion:The wrist-worn Actiwatch appears to be valid and reliable for estimating energy expenditure and physical activity intensity in children aged 8 to 10 years.

Concurrent Validity of ActiGraph GT3X+ and Axivity AX3 Accelerometers for Estimating Physical Activity and Sedentary Behavior

2020 ◽  
pp. 1-8
Author(s):  
Leila Hedayatrad ◽  
Tom Stewart ◽  
Scott Duncan
Keyword(s):  
Physical Activity ◽  
Light Intensity ◽  
Sedentary Behavior ◽  
Concurrent Validity ◽  
Criterion Measure ◽  
Physical Activity Intensity ◽  
Body Postures ◽  
Activity Intensity ◽  
Lower Back ◽  
Sensitivity Specificity

Introduction: Accelerometers are commonly used to assess time-use behaviors related to physical activity, sedentary behavior, and sleep; however, as new accelerometer technologies emerge, it is important to ensure consistency with previous devices. This study aimed to evaluate the concurrent validity of the commonly used accelerometer, ActiGraph GT3X+, and the relatively new Axivity AX3 (fastened to the lower back) for detecting physical activity intensity and body postures when using direct observation as the criterion measure. Methods: A total of 41 children (aged 6–16 years) and 33 adults (aged 28–59 years) wore both monitors concurrently while performing 10 prescribed activities under laboratory conditions. The GT3X+ data were categorized into different physical activity intensity and posture categories using intensity-based cut points and ActiGraph proprietary inclinometer algorithms, respectively. The AX3 data were first converted to ActiGraph counts before being categorized into different physical activity intensity categories, while activity recognition models were used to detect the target postures. Sensitivity, specificity, and the balanced accuracy for intensity and posture category classification were calculated for each accelerometer. Differences in balanced accuracy between the devices and between children and adults were also calculated. Results: Both accelerometers obtained 74–96% balanced accuracy, with the AX3 performing slightly better (∼4% higher, p < .01) for detecting postures and physical activity intensity. Error in both devices was greatest when contrasting sitting/standing, sedentary/light intensity, and moderate/light intensity. Conclusion: In comparison with the GT3X+ accelerometer, AX3 was able to detect various postures and activity intensities with slightly higher balanced accuracy in children and adults.

System for Observing Staff Promotion of Activity and Nutrition (SOSPAN)

2014 ◽  
Vol 11 (1) ◽  
pp. 173-185 ◽  
Author(s):  
R. Glenn Weaver ◽  
Michael W. Beets ◽  
Collin Webster ◽  
Jennifer Huberty
Keyword(s):  
Physical Activity ◽  
Sedentary Behavior ◽  
Direct Observation ◽  
Reliability And Validity ◽  
Afterschool Programs ◽  
Frontline Staff ◽  
Validity Data ◽  
Child Physical Activity ◽  
Out Of School Time ◽  
School Time

Background:Frontline-staff are critical to achieving policies related to child physical activity and nutrition (PAaN) in out-of-school-time programs (OSTP). Recent policies call upon staff to demonstrate behaviors related to PAaN. Currently, no instrument exists to measure these behaviors. This study fills the gap between policy mandates and staff behaviors by describing the development of the System for Observing Staff Promotion of Activity and Nutrition (SOSPAN) in OSTP.Methods:SOSPAN items were aligned with existing OSTP policies. Reliability and validity data of SOSPAN were collected across 8 OSTP: 4 summer day camps and 4 afterschool programs. Validity of SOSPAN staff behaviors/management of PA was established using the percent of children active measured concurrently via direct observation.Results:A total of 6437 scans were performed. Interrater percent agreement ranged from 74%–99% across PAaN behaviors. Children’s activity was associated with staff facilitative behaviors/management, such as playing with the children and providing 2 or more activities for children to choose, while prohibitive behaviors/management, such as waiting in line were related to increased sedentary behavior. Staff nutrition behaviors were observed in less than 0.6% of scans.Conclusion:SOSPAN is a reliable and valid tool to assess staff behaviors/management of PAaN in OSTPs.

scholarly journals Reexamination of Accelerometer Calibration with Energy Expenditure as Criterion: VO2net Instead of MET for Age-Equivalent Physical Activity Intensity

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3377 ◽  
Author(s):  
Daniel Arvidsson ◽  
Jonatan Fridolfsson ◽  
Christoph Buck ◽  
Örjan Ekblom ◽  
Elin Ekblom-Bak ◽  
...  
Keyword(s):  
Physical Activity ◽  
Age Groups ◽  
Accelerometer Data ◽  
Physical Activity Intensity ◽  
Free Living ◽  
Activity Intensity ◽  
Age Related ◽  
Younger Age ◽  
Metabolic Equivalent Of Task ◽  
Adolescents And Adults

Accelerometer calibration for physical activity (PA) intensity is commonly performed using Metabolic Equivalent of Task (MET) as criterion. However, MET is not an age-equivalent measure of PA intensity, which limits the use of MET-calibrated accelerometers for age-related PA investigations. We investigated calibration using VO2net (VO2gross − VO2stand; mL⋅min−1⋅kg−1) as criterion compared to MET (VO2gross/VO2rest) and the effect on assessment of free-living PA in children, adolescents and adults. Oxygen consumption and hip/thigh accelerometer data were collected during rest, stand and treadmill walk and run. Equivalent speed (Speedeq) was used as indicator of the absolute speed (Speedabs) performed with the same effort in individuals of different body size/age. The results showed that VO2net was higher in younger age-groups for Speedabs, but was similar in the three age-groups for Speedeq. MET was lower in younger age-groups for both Speedabs and Speedeq. The same VO2net-values respective MET-values were applied to all age-groups to develop accelerometer PA intensity cut-points. Free-living moderate-and-vigorous PA was 216, 115, 74 and 71 min/d in children, adolescents, younger and older adults with VO2net-calibration, but 140, 83, 74 and 41 min/d with MET-calibration, respectively. In conclusion, VO2net calibration of accelerometers may provide age-equivalent measures of PA intensity/effort for more accurate age-related investigations of PA in epidemiological research.

scholarly journals Calibration and Evaluation of an Objective Measure of Physical Activity in Preschool Children

2005 ◽  
Vol 2 (3) ◽  
pp. 345-357 ◽  
Author(s):  
John R. Sirard ◽  
Stewart G. Trost ◽  
Karin A. Pfeiffer ◽  
Marsha Dowda ◽  
Russell R. Pate
Keyword(s):  
Physical Activity ◽  
Preschool Children ◽  
Interobserver Reliability ◽  
Objective Measure ◽  
Preschool Age ◽  
Physical Activity Intensity ◽  
Activity Intensity ◽  
Preschool Age Children ◽  
Trained Observers ◽  
Children’S Physical Activity

Background:The purposes of this study were 1) to establish accelerometer count cutoffs to categorize activity intensity of 3 to 5-y old-children and 2) to evaluate the accelerometer as a measure of children’s physical activity in preschool settings.Methods:While wearing an ActiGraph accelerometer, 16 preschool children performed five, 3-min structured activities. Receiver Operating Characteristic (ROC) curve analyses identified count cutoffs for four physical activity intensities. In 9 preschools, 281 children wore an ActiGraph during observations performed by three trained observers (interobserver reliability = 0.91 to 0.98).Results:Separate count cutoffs for 3, 4, and 5-y olds were established. Sensitivity and specificity for the count cutoffs ranged from 86.7% to 100.0% and 66.7% to 100.0%, respectively. ActiGraph counts/15 s were different among all activities (P < 0.05) except the two sitting activities. Correlations between observed and ActiGraph intensity categorizations at the preschools ranged from 0.46 to 0.70 (P < 0.001).Conclusions:The ActiGraph count cutoffs established and validated in this study can be used to objectively categorize the time that preschool-age children spend in different physical activity intensity levels.

scholarly journals Physical Activity Intensity Cut-Points for Wrist-Worn GENEActiv in Older Adults

2021 ◽  
Vol 2 ◽  
Author(s):  
François Fraysse ◽  
Dannielle Post ◽  
Roger Eston ◽  
Daiki Kasai ◽  
Alex V. Rowlands ◽  
...  
Keyword(s):  
Physical Activity ◽  
Older Adults ◽  
Classification Accuracy ◽  
Operating Characteristic ◽  
Sedentary Time ◽  
Vigorous Physical Activity ◽  
Physical Activity Intensity ◽  
Characteristic Analysis ◽  
Free Living ◽  
Activity Intensity

Purpose: This study aims to (1) establish GENEActiv intensity cutpoints in older adults and (2) compare the classification accuracy between dominant (D) or non-dominant (ND) wrist, using both laboratory and free-living data.Methods: Thirty-one older adults participated in the study. They wore a GENEActiv Original on each wrist and performed nine activities of daily living. A portable gas analyzer was used to measure energy expenditure for each task. Testing was performed on two occasions separated by at least 8 days. Some of the same participants (n = 13) also wore one device on each wrist during 3 days of free-living. Receiver operating characteristic analysis was performed to establish the optimal cutpoints.Results: For sedentary time, both dominant and non-dominant wrist had excellent classification accuracy (sensitivity 0.99 and 0.97, respectively; specificity 0.91 and 0.86, respectively). For Moderate to Vigorous Physical Activity (MVPA), the non-dominant wrist device had better accuracy (ND sensitivity: 0.90, specificity 0.79; D sensitivity: 0.90, specificity 0.64). The corresponding cutpoints for sedentary-to-light were 255 and 375 g · min (epoch independent: 42.5 and 62.5 mg), and those for the light-to-moderate were 588 and 555 g · min (epoch-independent: 98.0 and 92.5 mg) for the non-dominant and dominant wrist, respectively. For free-living data, the dominant wrist device resulted in significantly more sedentary time and significantly less light and MVPA time compared to the non-dominant wrist.

scholarly journals Comparison of Older and Newer Generation Active Style Pro Accelerometers in Physical Activity and Sedentary Behavior Surveillance under a Free-Living Environment

2019 ◽  
Vol 16 (9) ◽  
pp. 1597 ◽  
Author(s):  
Shohei Yano ◽  
Mohammad Javad Koohsari ◽  
Ai Shibata ◽  
Kaori Ishii ◽  
Levi Frehlich ◽  
...  
Keyword(s):  
Physical Activity ◽  
Sedentary Behavior ◽  
Correlation Coefficients ◽  
Epidemiological Studies ◽  
Living Environment ◽  
Activity Time ◽  
Free Living ◽  
Intra Class Correlation ◽  
Japanese Workers ◽  
The Difference

Background. Comparability of accelerometers in epidemiological studies is important for public health researchers. This study aimed to compare physical activity (light, LPA; moderate, MPA; and moderate-to-vigorous, MVPA) and sedentary behavior (SB) data collected using two Omron triaxial accelerometer generations (Active style Pro, ASP) among a sample of Japanese workers in a free-living environment. Methods. Thirty active and sedentary workers (24–62 years) wore two types of ASP accelerometers, the HJA-350IT (350IT) and the HJA-750C (750C), simultaneously for seven consecutive days to represent a typical week. The accelerometers estimated daily average step counts and time spent per day in LPA, MPA, and MVPA. If a participant had data for ≥4 days (>10 h/day) it was considered valid. The difference and agreement between the two ASPs were analyzed using a paired t-test, intra-class correlation coefficients (ICC), and a Bland–Altman analysis in total and for each type of worker. Results. Among all workers, the 750C measured significantly (p < 0.05) less SB, MPA, MVPA, and more LPA compared with the 350IT. The agreements in ICC were high (ICC ≥ 0.94). Conclusions. Compared with the 350IT, the newer generation 750C ASP accelerometer may not provide equivalent estimates of activity time, regardless of the type of physical activity.

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