title: Wrist-based cut-points for moderate- and vigorous-intensity physical activity for the Actical accelerometer in adults.
abstract: Wrist-based accelerometers are increasingly used to assess physical activity (PA) in population-based studies; however, cut-points to translate wrist-based accelerometer counts into PA intensity categories are still needed. The purpose of this study was to determine wrist-based cut-points for moderate- and vigorous-intensity ambulatory PA in adults for the Actical accelerometer. Healthy adults (n = 24) completed a four-phase treadmill exercise protocol (1.9, 3.0, 4.0 and 5.2 mph) while wearing an Actical accelerometer on their wrist. Metabolic equivalent of task (MET) levels were assessed by indirect calorimetry. Receiver operating characteristics (ROC) curves were generated to determine accelerometer counts that maximised sensitivity and specificity for classification of moderate (≥3 METs) and vigorous (>6 METs) ambulatory activity. The area under the ROC curves to discriminate moderate- and vigorous-intensity ambulatory activity were 0.93 (95% confidence interval [CI]: 0.90-0.97; P < 0.001) and 0.96 (95% CI: 0.94-0.99; P < 0.001), respectively. The identified cut-point for moderate-intensity ambulatory activity was 1031 counts per minute, which had a corresponding sensitivity and specificity of 85.6% and 87.5%, respectively. The identified cut-point for vigorous intensity ambulatory activity was 3589 counts per minute, which had a corresponding sensitivity and specificity of 88.0% and 98.7%, respectively. This study established intensity-specific cut-points for wrist-based wear of the Actical accelerometer which are recommended for quantification of moderate- and vigorous-intensity ambulatory activity.
authors.affiliation: a Center for Behavioral Cardiovascular Health, Department of Medicine , Columbia University Medical Center , New York , NY , USA.
authors.forename: Keith M
authors.initials: KM
authors.lastname: Diaz
authors.affiliation: a Center for Behavioral Cardiovascular Health, Department of Medicine , Columbia University Medical Center , New York , NY , USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Krupka
authors.affiliation: a Center for Behavioral Cardiovascular Health, Department of Medicine , Columbia University Medical Center , New York , NY , USA.
authors.forename: Melinda J
authors.initials: MJ
authors.lastname: Chang
authors.affiliation: a Center for Behavioral Cardiovascular Health, Department of Medicine , Columbia University Medical Center , New York , NY , USA.
authors.forename: Ian M
authors.initials: IM
authors.lastname: Kronish
authors.affiliation: a Center for Behavioral Cardiovascular Health, Department of Medicine , Columbia University Medical Center , New York , NY , USA.
authors.forename: Natalie
authors.initials: N
authors.lastname: Moise
authors.affiliation: b Department of Biostatistics, Mailman School of Public Health , Columbia University , New York , NY , USA.
authors.forename: Jeff
authors.initials: J
authors.lastname: Goldsmith
authors.affiliation: a Center for Behavioral Cardiovascular Health, Department of Medicine , Columbia University Medical Center , New York , NY , USA.|c Department of Psychiatry , Stony Brook University , Stony Brook , NY , USA.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Schwartz
mesh_terms: D056044:Actigraphy / Q000295:instrumentation* / Q000379:methods*; D000328:Adult; D002138:Calibration; D002153:Calorimetry, Indirect; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014953:Wrist; D055815:Young Adult
keywords: Physical activity; accelerometer; adults; calibration; validation