Validity of activity monitors worn at multiple nontraditional locations under controlled and free-living conditions in young adult women

2015 ◽  
Vol 40 (5) ◽  
pp. 448-456 ◽  
Author(s):  
Hideaki Kumahara ◽  
Makoto Ayabe ◽  
Misato Ichibakase ◽  
Akari Tashima ◽  
Maiko Chiwata ◽  
...  
Keyword(s):  
Young Adult ◽  
Vigorous Physical Activity ◽  
Real Life ◽  
Living Conditions ◽  
Practical Reasons ◽  
Adult Women ◽  
Young Adult Women ◽  
Free Living ◽  
Activity Monitors ◽  
Free Living Conditions

The purpose of this study was to examine the validity of counting steps and computing indices of moderate-to-vigorous physical activity (MVPA) using miniature activity monitors with 3-D technology worn at various locations under controlled (CON) and free-living conditions (FL). Kenz e-style2, Tanita Calorism Smart, and Omron Calori Scan HJA-306 activity monitors were assessed. Nine and 31 young adult women were assigned to the CON and FL studies, respectively. While walking or jogging on a treadmill at 5 different speeds, the subjects simultaneously carried the 3 different monitors in a pants pocket (PP), a chest shirt pocket, and a shoulder bag (B). Under the FL condition, the 3 monitors were placed only at the PP and B locations for practical reasons. Significant effects of monitor location and walking/jogging speed on the step count measured by the 3 monitors were evaluated under the CON condition. Monitors placed at both PP and B tended to underestimate the number of steps; however, there were no significant differences between the values obtained with the Kenz monitor and those obtained with a criterion accelerometer under the FL condition. Moreover, strong correlations were observed between steps measured by monitors placed at PP and steps measured by the criterion accelerometer. The amount of MVPA for the PP location and the non-carrying duration of the bag for the B location were considered to be important determinants of the accuracy of step counting under the FL condition. In conclusion, monitors placed at the PP location, especially the Kenz monitor, showed acceptable accuracy for young adult women in real-life settings. In contrast, MVPA indices assessed using these monitors showed limited validity.

Physical Activity Monitor Accuracy for Overground Walking and Free-Living Conditions Among Pregnant Women

2020 ◽  
Vol 3 (2) ◽  
pp. 100-109
Author(s):  
Christopher P. Connolly ◽  
Jordana Dahmen ◽  
Robert D. Catena ◽  
Nigel Campbell ◽  
Alexander H.K. Montoye
Keyword(s):  
Physical Activity ◽  
Pregnant Women ◽  
Living Conditions ◽  
Overground Walking ◽  
Third Trimester ◽  
Free Living ◽  
Activity Monitors ◽  
Step Counting ◽  
Physical Activity Monitors ◽  
Free Living Conditions

Purpose: We aimed to determine the step-count validity of commonly used physical activity monitors for pregnancy overground walking and during free-living conditions. Methods: Participants (n = 39, 12–38 weeks gestational age) completed six 100-step overground walking trials (three self-selected “normal pace”, three “brisk pace”) while wearing five physical activity monitors: Omron HJ-720 (OM), New Lifestyles 2000 (NL), Fitbit Flex (FF), ActiGraph Link (AG), and Modus StepWatch (SW). For each walking trial, monitor-recorded steps and criterion-measured steps were assessed. Participants also wore all activity monitors for an extended free-living period (72 hours), with the SW used as the criterion device. Mean absolute percent error (MAPE) was calculated for overground walking and free-living protocols and compared across monitors. Results: For overground walking, the OM, NL, and SW performed well (<5% MAPE) for normal and brisk pace walking trials, and also when trials were analyzed by actual speeds. The AG and FF had significantly greater MAPE for overground walking trials (11.9–14.7%). Trimester did affect device accuracy to some degree for the AG, FF, and SW, with error being lower in the third trimester compared to the second. For the free-living period, the OM, NL, AG, and FF significantly underestimated (>32% MAPE) actual steps taken per day as measured by the criterion SW (M [SD] = 9,350 [3,910]). MAPE for the OM was particularly high (45.3%). Conclusion: The OM, NL, and SW monitors are valid measures for overground step-counting during pregnancy walking. However, the OM and NL significantly underestimate steps by second and third trimester pregnant women in free-living conditions.

Comparison of Lifecorder EX and ActiGraph accelerometers under free-living conditions

2007 ◽  
Vol 32 (4) ◽  
pp. 753-761 ◽  
Author(s):  
James J. McClain ◽  
Cora L. Craig ◽  
Susan B. Sisson ◽  
Catrine Tudor-Locke
Keyword(s):  
Repeated Measures ◽  
Vigorous Physical Activity ◽  
Living Conditions ◽  
Moderate Activity ◽  
Free Living ◽  
Cut Points ◽  
Model Reliability ◽  
Vigorous Intensity ◽  
Fort Walton ◽  
Free Living Conditions

The Kenz Lifecorder EX (LC; Suzuken Co. Ltd., Nagoya, Japan) offers several potentially attractive features for researchers and practitioners compared with accelerometers such as the ActiGraph (AG; ActiGraph Health Services, Fort Walton Beach, Fla.). The purposes of this study were (i) to evaluate the LC’s intra-model reliability for outputs of steps and time spent in moderate, vigorous, and combined moderate plus vigorous physical activity (MVPA) and (ii) to compare the same LC vs. AG outputs under free-living conditions. Ten participants (n = 5 males) wore two LCs and one AG accelerometer during all waking hours on one day. Steps were outputted from all monitors. Additionally, two LC and five AG intensity derivations were used to assess time in moderate activity, vigorous activity, and MVPA. Intra-class correlations (ICC) were used to assess intra-model reliability between LCs. Paired t tests and repeated-measures analyses of variance (ANOVAs) were used to assess differences between the two LCs and LC vs. AG outputs of steps and time in various intensity derivations where appropriate. No significant differences were detected between outputs from different LCs (ICCs ranged from 0.95 to 0.99). The LC detected significantly fewer steps vs. AG (mean difference = 1516 steps). All LC vs. AG vigorous-intensity derivations provided similar outputs. Additionally, comparable estimates of MVPA time were produced by one of two LC intensity derivations compared with specific AG cut points established each by Freedson, Hendelman (walking), and Matthews. LC displayed high inter-model reliability. Although the LC detected fewer steps than the AG, the LC detects time in specific PA intensity categories comparable to several existing AG cut points.

Evaluating Relationships Between Sleep and Next-Day Physical Activity in Young Women

2020 ◽  
Vol 17 (9) ◽  
pp. 874-880
Author(s):  
Bruce W. Bailey ◽  
Landon S. Deru ◽  
William F. Christensen ◽  
Andrew J. Stevens ◽  
Stephen Tanner Ward ◽  
...  
Keyword(s):  
Physical Activity ◽  
Structural Equation ◽  
Vigorous Physical Activity ◽  
Equation Model ◽  
Driving Factor ◽  
Adult Women ◽  
Free Living ◽  
Wake Time ◽  
The Relationship ◽  
Free Living Conditions

Background: To evaluate the relationship between sleep and next-day physical activity (PA) under free-living conditions in women. Methods: Sleep and PA were measured objectively for 7 consecutive days by accelerometry in 330 young adult women (aged 17–25 y). A structural equation model was used to evaluate the relationship between the driving factor of sleep (total sleep or morning wake time) and the amount of nonsleep sedentary (SED) and moderate to vigorous physical activity (MVPA) each day. Results: With sleep duration as the driving factor, the estimates of βSED and βMVPA were −0.415 and −0.093, respectively (P ≤ .05). For every hour slept, a 24.9-minute reduction in SED time and a 5.58-minute reduction in MVPA were observed. With wake time as the driving factor, the estimates of βSED and βMVPA were −0.636 and −0.149, respectively. For every wake time that was 1 hour later, a 38.2-minute decrease in SED and a 8.9-minute decrease in MVPA (P ≤ .05) were observed. Conclusions: Women who wake later or who sleep longer tend to get less MVPA throughout the day. Getting up earlier and going to bed earlier may support behaviors that improve PA and lifestyle.

Methods for Activity Monitor Validation Studies: An Example With the Fitbit Charge

2018 ◽  
Vol 1 (3) ◽  
pp. 130-135 ◽  
Author(s):  
Kathryn J. DeShaw ◽  
Laura Ellingson ◽  
Yang Bai ◽  
Jeni Lansing ◽  
Maria Perez ◽  
...  
Keyword(s):  
Vigorous Physical Activity ◽  
High Specificity ◽  
Living Conditions ◽  
Kappa Statistics ◽  
Free Living ◽  
Reference Measure ◽  
Standardized Reporting ◽  
Advance Research ◽  
Low Sensitivity ◽  
Free Living Conditions

Purpose: To advance research practices with consumer monitors, standard validation methods are needed. This study provides an example of best practices through systematically evaluating the validity of the Fitbit Charge (FBC) under free-living conditions using a strong reference measure and robust measurement agreement methods. Methods: 94 healthy participants (Mage 41.8 ±9.3 yrs) wore a FBC and two research grade accelerometers (Actigraph GT3X and activPAL) as they went about normal activities for a week. Estimated daily minutes of moderate to vigorous physical activity (MVPA) from the FBC were compared against reference estimates obtained from the Sojourns Including Posture (SIP) methodology, while daily step counts were compared against the activPAL. Results: Correlations with reference indicators were high for average daily MVPA (r = 0.8; p < .0001) and steps (r = 0.76; p < .0001), but the FBC overestimated time spent in MVPA by 56% and steps by 15%. The mean absolute percent errors of MVPA and steps estimated by FBC were 71.5% and 30.0%, respectively. Neither of the MVPA and step estimates from the FBC fell into the ±10% equivalence zone set by the criterion. The Kappa statistics of the classification agreement between the two MVPA assessment methods was 0.32 with a low sensitivity of 30.1% but a high specificity of 96.7%. Conclusion: The FBC overestimated minutes of MVPA and steps when compared to both reference assessments in free-living conditions. Standardized reporting in future studies will facilitate comparisons with other monitors and with future versions of the FBC.

scholarly journals Fitbit Charge HR Wireless Heart Rate Monitor: Validation Study Conducted Under Free-Living Conditions (Preprint)

2017 ◽  
Author(s):  
Alexander Wilhelm Gorny ◽  
Seaw Jia Liew ◽  
Chuen Seng Tan ◽  
Falk Müller-Riemenschneider
Keyword(s):  
Heart Rate ◽  
Data Collection ◽  
Field Test ◽  
Vigorous Physical Activity ◽  
Living Conditions ◽  
Continuous Data ◽  
Free Living ◽  
Heart Rate Monitor ◽  
Predictive Values ◽  
Free Living Conditions

BACKGROUND Many modern smart watches and activity trackers feature an optical sensor that estimates the wearer’s heart rate. Recent studies have evaluated the performance of these consumer devices in the laboratory. OBJECTIVE The objective of our study was to examine the accuracy and sensitivity of a common wrist-worn tracker device in measuring heart rates and detecting 1-min bouts of moderate to vigorous physical activity (MVPA) under free-living conditions. METHODS Ten healthy volunteers were recruited from a large university in Singapore to participate in a limited field test, followed by a month of continuous data collection. During the field test, each participant would wear one Fitbit Charge HR activity tracker and one Polar H6 heart rate monitor. Fitbit measures were accessed at 1-min intervals, while Polar readings were available for 10-s intervals. We derived intraclass correlation coefficients (ICCs) for individual participants comparing heart rate estimates. We applied Centers for Disease Control and Prevention heart rate zone cut-offs to ascertain the sensitivity and specificity of Fitbit in identifying 1-min epochs falling into MVPA heart rate zone. RESULTS We collected paired heart rate data for 2509 1-min epochs in 10 individuals under free-living conditions of 3 to 6 hours. The overall ICC comparing 1-min Fitbit measures with average 10-s Polar H6 measures for the same epoch was .83 (95% CI .63-.91). On average, the Fitbit tracker underestimated heart rate measures by −5.96 bpm (standard error, SE=0.18). At the low intensity heart rate zone, the underestimate was smaller at −4.22 bpm (SE=0.15). This underestimate grew to −16.2 bpm (SE=0.74) in the MVPA heart rate zone. Fitbit devices detected 52.9% (192/363) of MVPA heart rate zone epochs correctly. Positive and negative predictive values were 86.1% (192/223) and 92.52% (2115/2286), respectively. During subsequent 1 month of continuous data collection (270 person-days), only 3.9% of 1-min epochs could be categorized as MVPA according to heart rate zones. This measure was affected by decreasing wear time and adherence over the period of follow-up. CONCLUSIONS Under free-living conditions, Fitbit trackers are affected by significant systematic errors. Improvements in tracker accuracy and sensitivity when measuring MVPA are required before they can be considered for use in the context of exercise prescription to promote better health.

scholarly journals Using Activity Monitors to Measure Physical Activity in Free-Living Conditions

2006 ◽  
Vol 86 (8) ◽  
pp. 1137-1145 ◽  
Author(s):  
Jaime E Berlin ◽  
Kristi L Storti ◽  
Jennifer S Brach
Keyword(s):  
Physical Activity ◽  
Living Conditions ◽  
Free Living ◽  
Activity Monitors ◽  
Free Living Conditions
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