Table 3.
Validity Studies Compared With Doubly Labeled Water and Indirect Calorimetry
| First Author, Year (Reference No.) | Device (Axis, Frequency, Epoch, Placement) | Study Population | Age Range, Years | Activity | Criterion | Algorithms | Findings |
|---|---|---|---|---|---|---|---|
| Neil-Sztramko, 2017 (59) | Actiwatch 2 (uniaxial, unspecified, 15 seconds, nondominant wrist) | 30 female participants | 40 (14.9)a | Treadmill walk/run at 2.0 mph, 3.0–3.5 mph, and fast self-selected speed; self-paced indoor walk at slow, medium, and fast speeds; stair ascend and descend; and a lift-and-carry task | METs calculated from Vo2 (mL/kg/minute) measured by indirect calorimetry | None | Correlation between ACs and METs: r = 0.69 |
| Lee, 2019 (57) | Actiwatch 2 (uniaxial, unspecified, 1 minute, both wrists) | 27 young adults | 18–26 | Treadmill run at 4, 6, 8, 10, and 12 km/h | METs calculated from Vo2 measured by indirect calorimetry | METs estimated by regression models including ACs and quadratic terms of ACs | Correlation between AC and METs: right wrist, r = 0.73; left wrist, r = 0.72. No significant biases between estimated and criterion METs |
| Chen, 2003 (63) | Actiwatch 64 (uniaxial, unspecified, 1 minute, dominant wrist) | 60 women | 20–52 | Structured exercise, including walking periods with average speeds of 0.6, 0.9, and 1.2 m/second and stepping periods with average speed of 12 steps/10 seconds, 18 steps/10 seconds, and 24 steps/minute. Laboratory-based spontaneous activities, including sitting, television viewing, deskwork, walking around the room, and voluntary exercises | EE (kcal) calculated from Vo2 and Vco2 measured by indirect calorimetry | EE estimated by nonlinear model including ACs | Correlation between AC and criterion EE: r = 0.646. Significant underestimation between estimated and criterion EE |
| Neil-Sztramko, 2017 (59) | ActiGraph GT3X+ (triaxial, unspecified, 15 seconds, nondominant wrist) | 30 female participants | 40 (14.9)a | Treadmill walk/run at 2.0 mph, 3.0–3.5 mph, and fast self-selected speed; self-paced indoor walk at slow, medium, and fast speeds; stair ascend and descend; and a lift-and-carry task | METs calculated from Vo2 (mL/kg/minute) measured by indirect calorimetry | None | Correlation between AC and METs: r = 0.69 |
| Lee, 2019 (57) | ActiGraph wGT3X (triaxial, unspecified, 1 minute, both wrists) | 27 young adults | 18–26 | Treadmill run at 4, 6, 8, 10, and 12 km/hour | METs calculated from Vo2 measured by indirect calorimetry | METs estimated by regression models including AC and quadratic terms of AC | Correlation between AC and METs: right wrist, r = 0.73; left wrist, r = 0.74 No significant biases between estimated and criterion METs |
| Ho, 2019 (58) | ActiGraph GT9X (triaxial, 30 Hz, 10-s, non-dominant wrist) | 90 adults | 22.9 (4.15)a | Treadmill walk/run at 4.8, 6.4, 8.0, 9.7, and 11.3 km/hour | EE (kcal/min) calculated from Vo2 (L/min) and Vco2 (L/min) measured by indirect calorimetry | 1) EE estimated by Freedson VM3 Combination (2011) available with ActiLife software 2) EE estimated by a linear model including AC, body weight, and heart rate | 1) The Freedson VM3 Combination model explained 38.4% of the variance in criterion EE and underestimated energy expenditure at each speed. 2) The linear model explained 80.2% of variance in criterion EE. Bias was not specified. |
| Ellingson, 2017 (61) | ActiGraph GT3X+ (triaxial, 100 Hz, 1 second and 15 seconds, right wrist) | 51 adults | 18–40 | Laboratory-based activities including supine resting, sitting reading a book, sitting typing, sitting fidgeting, standing reading a book, standing typing, standing fidgeting, climbing stairs, throwing/catching a ball, stationary biking, walking on a treadmill at 2 mph and 3 mph, walking at 3 mph typing, and running on a treadmill at 4.5 and 5.5 mph | METs calculated from Vo2 (mL/kg/minute) measured by indirect calorimetry | METs estimated from the Hildebrand linear method (43), Hildebrand nonlinear method, Staudenmayer linear method (47), and Staudenmayer random forest method (47) using acceleration | For the average across activities of all intensities, only the Hildebrand linear method was equivalent with the criterion METs. None of the methods was equivalent to the criterion METs within each intensity level. |
| Staudenmayer, 2015 (47) | ActiGraph GT3X+ (triaxial, 80 Hz, 15 seconds, dominant wrist) | 20 adults | 20–39 | Treadmill walk/run at 3.0 mph (5% grade), 4.0 mph (5% grade), and 5.5 mph laboratory-based free-living activities including stairs, tennis, shooting, fast walk, stacking boxes, raking, walking while carrying groceries, self-paced walk, golfing (swinging), slow walk, vacuuming, gardening, laundry, dusting, driving, office work | METs calculated from Vo2 (mL/kg/minute) measured by indirect calorimetry | METs estimated from linear model and machine-learning models (ANN, SVM, and RF) using acceleration | Cross-validation showed that linear, ANN, and RF models were unbiased and had good agreement with overall criterion METs. All models tended to overestimate METs when the actual METs were low and underestimated them when actual METs were high. |
| Stec, 2012 (44) | ActiGraph GT3X+ (triaxial, unspecified, 1-s, right wrist) | 30 adults | 21.7 (1.0)a | Resistance exercises, including machine bench press, machine shoulder press, machine squat, leg extension, leg curl, latissimus dorsi pull-down, triceps push down, and barbell biceps curl | EE (kcal) calculated from Vo2 measured by indirect calorimetry | None | Criterion EE only correlated with AC on the horizontal axis (r = −0.40), but not with AC on the other 2 axes or the sum of AC |
| Ellis, 2014 (46) | ActiGraph GT3X+ (triaxial, 30 Hz, 1 minute, nondominant wrist) | 40 adults | 35.8 (12.1)a | Laboratory-based household activities including laundry, window washing, dusting, dishes, and sweeping. Locomotion activities including stairs, slow walk, brisk walk, and jog | METs calculated from Vo2 (mL/kg/minute) measured by indirect calorimetry | METs estimated from RF machine-learning model | No significant biases between estimated and criterion METs |
| Strath, 2015 (62) | ActiGraph GT3X+ (triaxial, unspecified, 1 second, nondominant wrist) | 99 adults | ≥18 | Treadmill walk with speed from 40.2 to 107.2 m/minute in increments of 13.4 m/minute. Laboratory-based daily activities, including computer work, vacuuming, mopping/sweeping, carrying box of 3 weights, and walking with intermittent stair climbing | METs calculated from Vo2 (mL/kg/minute) measured by indirect calorimetry | METs estimated from TR machine-learning model using n-gram–based feature (unigrams) | No bias between estimated and criterion METs by leave-one-out validation. Nonsignificant increase in biases and overall error when applying model for 18–39 years age group to 40–64 years age group or ≥65 years age group |
| Hildebrand, 2014 (43) | ActiGraph GT3X+ (triaxial, 60 Hz, 1 second, nondominant wrist) | 30 adults | 18–65 | Laboratory-based activities, including lying supine, sitting, standing, taking off shoes, standing, moving 8 items on a bookshelf, writing a sentence, putting a paper in an envelope, sitting down, treadmill walk/run at 3, 5, and 8 km/hour, and stepping | Vo 2 (mL/kg/minute) measured by indirect calorimetry | Vo 2 estimated from linear regression model including the ENMO only | ENMO explained 75% of the variance in Vo2 |
| Melanson, 1995 (75) | CSA (uniaxial, unspecified, 5 seconds, nondominant wrist) | 28 adults | 21.0 (1.0)a for male participants; 21.0 (1.1)a for female participants | Treadmill walk/run at speeds of 4.8, 6.4, and 8.1 km/hour and 0%, 3%, and 6% grade | Vo 2 (mL/kg/minute) from indirect calorimetry, EE (kcal/min) calculated from Vo2 (L/min) | EE estimated using linear regression model including AC and body weight | Significant correlation between AC and Vo2 and EE: r = 0.89 and 0.81, respectively Linear regression model with R2 = 0.86; small mean difference between estimated and criterion EE by cross-validation |
| Swartz, 2000 (60) | CSA (uniaxial, unspecified, 60 seconds, dominant wrist) | 70 adults | 19–74 | Laboratory-based yard work, occupational, housework, family care, conditioning and recreational activities | METs calculated from Vo2 (mL/kg/minute) measured by indirect calorimetry | None | Significant correlation between AC and criterion METs: r = 0.181 |
| Hildebrand, 2014 (43) | GENEActiv (triaxial, 60 Hz, 1 second, nondominant wrist) | 30 adults | 18–65 | Laboratory-based activities, including lying supine, sitting, standing; taking off shoes; standing; moving 8 items on a bookshelf; writing a sentence; putting a paper in an envelope; sitting down; treadmill walk/run at 3, 5, and 8 km/hour; and stepping | Vo 2 (mL/kg/minute) measured by indirect calorimetry | Vo 2 estimated from linear regression model including the ENMO only | ENMO explained 76% of the variance in Vo2 |
| Duncan, 2020 (48) | GENEActiv (triaxial, 80 Hz, 1 second, both wrists) | 23 adults | 55–77 | Laboratory-based activities, including lying supine, seated reading, slow walking, medium walking, fast walking, folding laundry, sweeping the floor, and cycling | METs calculated from Vo2 (mL/kg/minute) measured by indirect calorimetry | None | Significant correlations between ENMO and criterion METs for nondominant wrist: r = 0.188 or 0.259 with cycling removed Significant correlations between ENMO and criterion METs for dominant wrist: r = 0.174 or 0.270 with cycling removed |
| Montoye, 2015 (45) | GENEActiv (triaxial, 20 Hz, 30 seconds, both wrists) | 39 adults | 22.1 (4.3)a | Laboratory-based free-living activities, including lying down, reading, playing a computer game, standing, laundry, sweeping, walking slowly, walking fast, jogging, cycling, stair use, biceps curls, squats | METs calculated from Vo2 (mL/kg/minute) measured by indirect calorimetry | METs estimated by ANN machine-learning model using 4 different feature sets | Significant correlation between estimated and criterion METs by leave-one-out cross-validation: r = 0.84 to 0.87 No statistically significant bias between estimated and criterion METs |
| Sirichana, 2017 (65) | GENEActiv (triaxial, 40 Hz, 60 seconds, both wrists) | 20 adults | 21 (1)a | Laboratory-based activities, including lying on back; sitting and reading a book; siting and doing computer work; washing dishes; sweeping; stacking and organizing chairs; treadmill walk at 1.5, 3, 4, and 6 mph and 0%, 3%, and 8% grade | METs calculated from Vo2 (mL/kg/minute) measured by indirect calorimetry | Piecewise linear regression model with SVMgs as dependent variable and METs as independent variable (linear spline at 6 METs) | Significant correlations between SVMgs and METs by regression model: nondominant wrist, R2 = 0.85; dominant wrist, R2 = 0.86 |
| van Hees, 2011 (13) | GENEA (triaxial, 40 Hz, 1 second, each wrist for half of the participants) | 30 pregnant and 65 nonpregnant women | 20–35 | Free-living conditions for 10 days | PAEE (MJ/day) derived from doubly labeled water | PAEE estimated from regression models using raw acceleration | Leave-one-out cross-validation showed acceleration explained 19% of the variance in criterion PAEE for nonpregnant women No statistically significant biases between estimated and criterion PAEE for nonpregnant women Nonsignificant correlation between acceleration and criterion PAEE for pregnant women |
| Esliger, 2011 (64) | GENEA (triaxial, 80 Hz, 1 minute, both wrists) | 60 adults | 40–65 | Laboratory-based activities, including lateral recumbent; seated computer work; standing; window washing; washing dishes; shelf stacking; sweeping; treadmill walk/run at 4, 5, 6, 8, 10, and 12 km/hour; stair ascent/descent at 80 steps/minute; and brisk and medium free-living walk | METs calculated from Vo2 (mL/kg/minute) measured by indirect calorimetry | None | Correlation between SVMgs and METs: left wrist, r = 0.86; right wrist, r = 0.83 |
| Correa, 2016 (74) | Actical (omnidirectional, 32 Hz, 1 minute, dominant wrist) | 70 adults | 42 (13)a | Free-living conditions for 1 week | PAEE (kcal/day) derived from doubly labeled water | PAEE estimates from Actical | Significantly overestimation between estimated and criterion PAEE |
| White, 2019 (14) | Axivity AX3 (triaxial, 100 Hz, 5 seconds, both wrists) | 193 adults | 40–66 | Free-living conditions for 9–14 days | PAEE (kJ/day/kg) derived from doubly labeled water | PAEE estimated from 4 models developed by White et al., 2016 (15) | Correlation between estimated and criterion PAEE: dominant wrist, r = 0.61 to 0.65; nondominant wrist, r = 0.63 to 0.68 No statistically significant biases between estimated and criterion PAEE |
| Patterson, 1993 (56) | Ambulatory monitoring actigraph (uniaxial, 10 Hz, unspecified, nondominant wrist) | 15 adults | 22–38 | Sedentary activities, including mental arithmetic task, self-paced reading, self-paced typing, and video game using a joy stick Graded activities, including treadmill walk/run at 5% grade and at 30%, 60%, 75%, and 90% of individual Vo2max; stepping at 20 and 36 steps/minute, and knee bends at 28 and 48 bends/minute |
Vo 2 (mL/kg/minute) from indirect calorimetry | None | Significant correlation between AC and Vo2: physical activity, r = 0.73; sedentary activity, r = 0.46 |
Abbreviations: AC, activity count; ANN, artificial neural network; CSA, Computer Science and Applications; EE, energy expenditure; ENMO, Euclidian norm minus one; MET, metabolic equivalent; PAEE, physical activity energy expenditure; RF, random forest; SVM, support vector machine; SVMgs, sum of vector magnitudes with gravity subtracted; TR, decision tree; Vo2, oxygen consumption.
a Values are expressed as mean (standard deviation).