across different lifestyle PA domains) to accelerometer cut-points that were calibrated during treadmill walking ( Freedson, Melanson, & Sirard, 1998 ; Copeland & Esliger, 2009 ). One would expect these thresholds would have higher validity for walking than free-living activities. Accelerometer cut-points
Liane S. Lewis, James Hernon, Allan Clark and John M. Saxton
Claudia Fischer, Mine Yılıdrım, Jo Salmon and Mai J.M. Chinapaw
Actigraph accelerometers are hypothesized to be valid measurements for assessing children’s sedentary time. However, there is considerable variation in accelerometer cut-points used. Therefore, we compared the most common accelerometer sedentary cut-points of children performing sedentary behaviors. Actigraph Actitrainer uniaxial accelerometers were used to measure children’s activity intensity (29 children, 5-11 years old) during different activities, namely playing computer games, nonelectronic sedentary games, watching television and playing outdoors. A structured protocol was the criterion for assessing the validity of four common cut-points (100, 300, 800, 1100 counts/minute). The median counts during all sedentary behaviors were below the lowest comparison cut-point of 100 cpm. The 75th percentile values for the sedentary behaviors were always below the cut-point of 300 cpm. Our results suggest that the cut-point of <100 cpm is the most appropriate.
Scott E. Crouter, Diane M. DellaValle, Jere D. Haas, Edward A. Frongillo and David R. Bassett
The purpose of this study was to compare the 2006 and 2010 Crouter algorithms for the ActiGraph accelerometer and the NHANES and Matthews cut-points, to indirect calorimetry during a 6-hr free-living measurement period.
Twenty-nine participants (mean ± SD; age, 38 ± 11.7 yrs; BMI, 25.0 ± 4.6 kg·m-2) were monitored for 6 hours while at work or during their leisure time. Physical activity (PA) data were collected using an ActiGraph GT1M and energy expenditure (METs) was measured using a Cosmed K4b2. ActiGraph prediction equations were compared with the Cosmed for METs and time spent in sedentary behaviors, light PA (LPA), moderate PA (MPA), and vigorous PA (VPA).
The 2010 Crouter algorithm overestimated time spent in LPA, MPA, and VPA by 9.0%−44.5% and underestimated sedentary time by 20.8%. The NHANES cut-points overestimated sedentary time and LPA by 8.3%−9.9% and underestimated MPA and VPA by 50.4%−56.7%. The Matthews cut-points overestimated sedentary time (9.9%) and MPA (33.4%) and underestimated LPA (25.7%) and VPA (50.1%). The 2006 Crouter algorithm was within 1.8% of measured sedentary time; however, mean errors ranged from 34.4%−163.1% for LPA, MPA, and VPA.
Of the ActiGraph prediction methods examined, none of them was clearly superior for estimating free-living PA compared with indirect calorimetry.
Tiego A. Diniz, Fabricio E. Rossi, Clara Suemi da Costa Rosa, Jorge Mota and Ismael F. Freitas-Junior
The objective of this study was to compare moderate-to-vigorous physical activity (MVPA), minutes per week (min/wk), and fulfillment of the current recommendation (150 min/wk of MVPA) based on different cut-points in postmenopausal women. The sample was composed of 233 postmenopausal women aged 59.8 ± 6.7 years old. MVPA was measured using triaxial accelerometers. Accelerometers were initialized to collect in 60-s epochs. Participants were included if using at least 5 days. MVPA min/wk were obtained using Freedson, Troiano, Copeland, and Sasaki cut-points. Box-plot indicated large mean differences between almost all cut-points, except for Freedson and Troiano (9.3 [95% LoA: –5.6; 24.3] min/wk). The proportion of women who achieved 150 min/wk of MVPA was similar between Freedson and Troiano (31% vs. 30%). Sasaki and Copeland cut-points resulted in a greater proportion than other cut-points. We concluded that the cut-points analyzed generated different results in MVPA min/wk and low agreement when using current guidelines for MVPA pattern classification, except for the comparisons between Freedson and Troiano cut-points.
C. Tudor-Locke, D.R. Bassett Jr., W.J. Rutherford, B.E. Ainsworth, C.B. Chan, K. Croteau, B. Giles-Corti, G. Le Masurier, K. Moreau, J. Mrozek, J.-M. Oppert, A. Raustorp, S.J. Strath, D. Thompson, M.C. Whitt-Glover, B. Wilde and J.R. Wojcik
The goal of this study was to establish preliminary criterion-referenced cut points for adult pedometer-determined physical activity (PA) related to weight status defined by body mass index (BMI).
Researchers contributed directly measured BMI and pedometer data that had been collected (1) using a Yamax-manufactured pedometer, (2) for a minimum of 3 days, (3) on ostensibly healthy adults. The contrasting groups method was used to identify age- and gender-specific cut points for steps/d related to BMI cut points for normal weight and overweight/obesity (defined as BMI <25 and ≥25 kg/m2, respectively).
Data included 3127 individuals age 18 to 94 years (976 men, age = 46.8 ± 15.4 years, BMI = 27.3 ± 4.9; 2151 women, age = 47.4 ± 14.9 years, BMI = 27.6 ± 6.4; all gender differences NS). Best estimated cut points for normal versus overweight/obesity ranged from 11,000 to 12,000 steps/d for men and 8000 to 12,000 steps/d for women (consistently higher for younger age groups).
These steps/d cut points can be used to identify individuals at risk, or the proportion of adults achieving or falling short of set cut points can be reported and compared between populations. Cut points can also be used to set intervention goals, and they can be referred to when evaluating program impact, as well as environmental and policy changes.
Jennifer Ryan, Michael Walsh and John Gormley
This study investigated the ability of published cut points for the RT3 accelerometer to differentiate between levels of physical activity intensity in children with cerebral palsy (CP). Oxygen consumption (metabolic equivalents; METs) and RT3 data (counts/min) were measured during rest and 5 walking trials. METs and corresponding counts/min were classified as sedentary, light physical activity (LPA), and moderate to vigorous physical activity (MVPA) according to MET thresholds. Counts were also classified according to published cut points. A published cut point exhibited an excellent ability to classify sedentary activity (sensitivity = 89.5%, specificity = 100.0%). Classification accuracy decreased when published cut points were used to classify LPA (sensitivity = 88.9%, specificity = 79.6%) and MVPA (sensitivity = 70%, specificity = 95–97%). Derivation of a new cut point improved classification of both LPA and MVPA. Applying published cut points to RT3 accelerometer data collected in children with CP may result in misclassification of LPA and MVPA.
Jane F. Hislop, Cathy Bulley, Tom H. Mercer and John J. Reilly
This study compared accelerometry cut points for sedentary behavior, light and moderate to vigorous intensity activity (MVPA) against a criterion measure, the Children’s Activity Rating Scale (CARS), in preschool children. Actigraph accelerometry data were collected from 31 children (4.4 ± 0.8 yrs) during one hour of free-play. Video data were coded using the CARS. Cut points by Pate et al., van Cauwenberghe et al., Sirard et al. and Puyau et al. were applied to calculate time spent in sedentary, light and MVPA. Repeated-measures ANOVA and paired t tests tested differences between the cut points and the CARS. Bland and Altman plots tested agreement between the cut points and the CARS. No significant difference was found between the CARS and the Puyau et al. cut points for sedentary, light and MVPA or between the CARS and the Sirard et al. cut point for MVPA. The present study suggests that the Sirard et al. and Puyau et al. cut points provide accurate group-level estimates of MVPA in preschool children.
Diego Augusto Santos Silva, Mark Tremblay, Andreia Pelegrini, Roberto Jeronimo dos Santos Silva, Antonio Cesar Cabral de Oliveira and Edio Luiz Petroski
Criterion-referenced cut-points for health-related fitness measures are lacking. This study aimed to determine the associations between aerobic fitness and high blood pressure levels (HBP) to determine the cut-points that best predict HBP among adolescents.
This cross-sectional school-based study with sample of 875 adolescents aged 14–19 years was conducted in southern Brazil. Aerobic fitness was assessed using the modified Canadian Aerobic Fitness Test (mCAFT). Systolic and diastolic blood pressure were measured by the oscillometric method with a digital sphygmomanometer. Analyses controlled for sociodemographic variables, physical activity, body mass and biological maturation.
Receiver Operating Characteristic (ROC) curves demonstrated that mCAFT measures could discriminate HBP in both sexes (female: AUC = 0.70; male: AUC = 0.63). The cut-points with the best discriminatory power for HBP were 32 mL·kg-1·min-1 for females and 40 mL·kg-1·min-1 for males. Females (OR = 8.4; 95% CI: 2.1, 33.7) and males (OR: 2.5; CI 95%: 1.2, 5.2) with low aerobic fitness levels were more likely to have HBP.
mCAFT measures are inversely associated with BP and cut-points from ROC analyses have good discriminatory power for HBP.
Ian Cook, Marianne Alberts and Estelle V. Lambert
We describe the effect of 2 different accelerometer cut-points on physical activity (PA) patterns in rural and urban black South African women.
Hip-mounted uni-axial accelerometers were worn for 6 to 7 days by rural (n = 272) and urban (n = 16) participants. Twenty-hour (4 AM to 12 AM) PA counts (cts) and volumes (min·day−1) were extracted: sedentary (SED, <100 cts·min−1), light (100–759 cts·min−1), moderate-1 (MOD1, 760–1951 cts·min−1), moderate-2 to vigorous (MOD2VG, ≥1952 cts·min−1), and bouts ≥10 min for ≥760 cts·min−1 (MOD1VGbt) and ≥1952 cts·min−1 (MOD2VGbt).
Valid data were obtained from 263 rural women and 16 urban women. Total counts and average counts were higher (+80,399 cts·day−1, +98 cts·min−1.day−1) (P < .01), SED lower (−61 min·day−1, P = .0042), MOD1 higher (+65 min·day−1, P < .0001), and MOD1VGbt higher (+19 min·day−1, P = .0179) in rural women compared with urban women. Estimated adherence (≥30 min·day−1 for 5 days·wk−1) was 1.4-fold higher in rural women than urban women for MOD-1VGbt, but 3.3-fold higher in urban women than rural women for MOD2VGbt.
Rural women accumulate greater amounts of PA than urban women within a particular count band. Depending on which moderate PA cut-point was used to estimate PA public health adherence, rural women could be classified as less physically active than urban women.
Quinn Malone, Steven Passmore and Michele Maiers
accelerometers is in the choice of cut points, thresholds that define the divisions between sedentary behavior, light, moderate, vigorous, and very vigorous activity based on the number of counts per unit time (usually designated as counts per minute, cpm). Two common cut-point sets used in studies concerning