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

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.

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

Journal of Physical Activity and Health ◽

10.1123/jpah.2012-0290 ◽

2014 ◽

Vol 11 (4) ◽

pp. 860-863 ◽

Cited By ~ 16

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.

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Physical activity intensity and subjective well-being in healthy adults

Journal of Health Psychology ◽

10.1177/1359105317691589 ◽

2017 ◽

Vol 24 (9) ◽

pp. 1257-1267 ◽

Cited By ~ 14

Author(s):

Gregory A Panza ◽

Beth A Taylor ◽

Paul D Thompson ◽

C Michael White ◽

Linda S Pescatello

Keyword(s):

Physical Activity ◽

Sedentary Behavior ◽

Well Being ◽

Healthy Adults ◽

Moderate Intensity ◽

Subjective Well Being ◽

Physical Activity Intensity ◽

Psychological Well Being ◽

Negatively Associated ◽

Activity Intensity

The effect of physical activity intensity on subjective well-being has not been well established. We examined this relationship among 419 healthy adults using objective and subjective physical activity measurements (sample size varied among well-being assessments). For accelerometers, light-intensity physical activity positively associated with psychological well-being ( n = 150) and negatively associated with depression ( n = 99); moderate intensity negatively associated with pain severity ( n = 419) and positively associated with psychological well-being; sedentary behavior negatively associated with psychological well-being and positively associated with depression ( ps < .05). These findings were generally consistent with subjective measurements of physical activity (Question 8, Paffenbarger Questionnaire). Higher levels of sedentary behavior are associated with lower subjective well-being.

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Physical activity intensity, sedentary behavior, body composition and physical fitness in 4-year-old children: results from the ministop trial

International Journal of Obesity ◽

10.1038/ijo.2016.54 ◽

2016 ◽

Vol 40 (7) ◽

pp. 1126-1133 ◽

Cited By ~ 52

Author(s):

M H Leppänen ◽

C Delisle Nyström ◽

P Henriksson ◽

J Pomeroy ◽

J R Ruiz ◽

...

Keyword(s):

Physical Activity ◽

Body Composition ◽

Physical Fitness ◽

Sedentary Behavior ◽

Physical Activity Intensity ◽

Activity Intensity

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Validity and Comparability of a Wrist-Worn Accelerometer in Children

Journal of Physical Activity and Health ◽

10.1123/jpah.9.3.389 ◽

2012 ◽

Vol 9 (3) ◽

pp. 389-393 ◽

Cited By ~ 43

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.

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Comparison of a Wearable Tracker with Actigraph for Classifying Physical Activity Intensity and Heart Rate in Children

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16152663 ◽

2019 ◽

Vol 16 (15) ◽

pp. 2663

Author(s):

Kang ◽

Kim ◽

Byun ◽

Suk ◽

Lee

Keyword(s):

Physical Activity ◽

Sedentary Behavior ◽

Validity And Reliability ◽

Physical Activity Intensity ◽

Intra Class Correlation ◽

Activity Intensity ◽

Research Grade ◽

Vigorous Intensity ◽

High Degree

Introduction: To examine the validity and reliability of the Fitbit Charge HR (FCH), wrist-worn ActiGraph (AG) accelerometers were used for assessing the classification of physical activity (PA) into intensity categories in children. Methods: Forty-three children (n = 43) participated in the study. Each participant completed 3 min bouts of 12 PAs ranging from sedentary to vigorous intensity while simultaneously wearing FCH and AG on both hands, a Polar HR monitor, and a portable indirect calorimeter. Total time spent in different PA intensity levels measured by FCH and AG were compared to the indirect calorimetry. Results: The highest classification accuracy values of sedentary behavior was 81.1% for FCH. The highest classification (72.4%) of light intensity PA was observed with Crouter’s algorithm from the non-dominant wrist. Crouter’s algorithm also show the highest classification (81.8%) for assessing moderate to vigorous intensity PA compared to FCH (70.8%). Across the devices, a high degree of reliability was found in step measurements, ranging from an intra-class correlation (ICC) = 0.92 to an ICC = 0.94. The reliability of the AG and the FCH showed high agreement for each variable. Conclusion: The FCH shows better validity for estimating sedentary behavior and similar validity for assessing moderate to vigorous PA compared to the research-grade monitor. Across the devices, the reliability showed the strongest association.

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The Effect of the Presence of an Internet-Connected Mobile Tablet Computer on Physical Activity Behavior in Children

Pediatric Exercise Science ◽

10.1123/pes.2017-0051 ◽

2018 ◽

Vol 30 (1) ◽

pp. 150-156 ◽

Cited By ~ 2

Author(s):

Mallory S. Kobak ◽

Andrew Lepp ◽

Michael J. Rebold ◽

Hannah Faulkner ◽

Shannon Martin ◽

...

Keyword(s):

Physical Activity ◽

Sedentary Behavior ◽

Physical Activity Behavior ◽

Mobile Internet ◽

Tablet Computer ◽

Physical Activity Intensity ◽

Activity Intensity ◽

Metabolic Equivalents ◽

Activity Behavior ◽

Sedentary Activities

Background: Mobile Internet-connected electronic devices provide access to activities that have traditionally been associated with sedentary behavior. Because they are portable, these devices can be utilized in any environment. Therefore, providing children with access to these devices in environments that typically promote physical activity may result in a reduction in physical activity behavior. Purpose: To assess children’s physical and sedentary (ie, sitting) activity with and without the presence of a mobile Internet-connected tablet computer. Methods: A total of 20 children [6.7 (1.9) y old] participated in 2 simulated recess conditions in a gymnasium on separate days. During each condition, children had free-choice access physical activity options and a table of sedentary activities for 40 minutes. During 1 session, the iPad was present, and in the other session, it was not. Physical activity was monitored via an accelerometer, and sedentary time was monitored via a stopwatch. Results: Children significantly (P ≤ .03) reduced average physical activity intensity and increased their sedentary behavior with the iPad present [4.4 (4.0) metabolic equivalents/min and 20.9 (12.4) min sitting] versus the condition without the iPad present [5.3 (4.0) metabolic equivalents/min and 13.6 (13.2) min sitting]. Conclusion: Introducing an mobile Internet-connected tablet computer into a gymnasium reduced children’s physical activity intensity by 17% and increased sedentary behavior by 54%.

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