Dataset Information

Individualized Relative-Intensity Physical Activity Accelerometer Cut Points.

ABSTRACT:

Purpose

Physical activity (PA) intensity is expressed as either absolute or relative intensity. Absolute intensity refers to the energy required to perform an activity. Relative intensity refers to a level of effort that takes into account how hard an individual is working relative to their maximum capacity. We sought to develop methods for obtaining individualized relative-intensity accelerometer cut points using data from a maximal graded exercise treadmill test (GXT) so that each individual has their own cut point.

Methods

A total of 2363 men and women 38 to 50 yr old from the CARDIA fitness study wore ActiGraph 7164 accelerometers during a maximal GXT and for seven consecutive days in 2005-2006. Using mixed-effects regression models, we regressed accelerometer counts on heart rate as a percentage of maximum (%HRmax) and on RPE. Based on these two models, we obtained a moderate-intensity (%HRmax = 64% or RPE = 12) count cut point that is specific to each participant. We applied these subject-specific cut points to the available CARDIA accelerometer data.

Results

Using RPE, the mean moderate-intensity accelerometer cut point was 4004 (SD = 1120) counts per minute. On average, cut points were higher for men (4189 counts per minute) versus women (3865 counts per minute) and were higher for Whites (4088 counts per minute) versus African Americans (3896 counts per minute). Cut points were correlated with body mass index (rho = -0.11) and GXT duration (rho = 0.33). Mean daily minutes of absolute- and relative-intensity moderate to vigorous PA were 34.1 (SD = 31.1) min·d and 9.1 (SD = 18.2) min·d, respectively. RPE cut points were higher than those based on %HRmax. This is likely due to some participants ending the GXT before achieving their HRmax.

Conclusions

Accelerometer-based relative-intensity PA may be a useful measure of intensity relative to maximal capacity.

SUBMITTER: Siddique J

PROVIDER: S-EPMC6962549 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature

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Publications

Individualized Relative-Intensity Physical Activity Accelerometer Cut Points.

Siddique Juned J Aaby David D Montag Samantha E SE Sidney Stephen S Sternfeld Barbara B Welch Whitney A WA Carnethon Mercedes R MR Liu Kiang K Craft Lynette L LL Pettee Gabriel Kelley K Barone Gibbs Bethany B Reis Jared P JP Freedson Patty P

Medicine and science in sports and exercise 20200201 2

<h4>Purpose</h4>Physical activity (PA) intensity is expressed as either absolute or relative intensity. Absolute intensity refers to the energy required to perform an activity. Relative intensity refers to a level of effort that takes into account how hard an individual is working relative to their maximum capacity. We sought to develop methods for obtaining individualized relative-intensity accelerometer cut points using data from a maximal graded exercise treadmill test (GXT) so that each indi ...[more]

PMID: 31524826

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Project description:BackgroundIncorporating physical activity into lifestyle routines is recommended for individuals with type 2 diabetes. Accelerometers offer a promising method for objectively measuring physical activity and for assessing interventions. However, the existing literature for accelerometer-measured physical activity among middle-aged and older adults with type 2 diabetes is lacking.ObjectiveThis study aims to identify research studies in which accelerometer-based cut points were used to classify the physical activity intensity of middle-aged to older adults with type 2 diabetes as sedentary, light, moderate, vigorous, and very vigorous, and to determine if validated accelerometer cut points specifically for this population exist.MethodsWe followed the Joanna Briggs Institute methodology for scoping reviews. Between June 23 and July 12, 2020, two reviewers independently screened records from four databases (PubMed, Web of Science, Embase, Engineering Village) and the ActiGraph Corp web site for eligible studies that included patients with type 2 diabetes with a sample mean age ≥50 years, used research-grade accelerometers, applied cut points to categorize objectively measured physical activity, and were available in English. We excluded studies reporting exclusively steps or step counts measured by accelerometers or pedometers and conference abstracts or other sources that did not have a full text available. Data extraction was completed using Microsoft Excel. Data for the following variables were tabulated based on frequency distributions: study design, accelerometer type, device placement, epoch length, total wear time, and cut points used. Study aims and participant demographic data were summarized.ResultsA total of 748 records were screened at the abstract level, and 88 full-text articles were assessed for eligibility. Ultimately, 46 articles were retained and analyzed. Participants' mean ages ranged from 50 to 79.9 years. The ActiGraph accelerometer and the Freedson et al and Troiano et al counts-per-minute cut points were the most frequently used across the literature. Freedson et al and Troiano et al counts-per-minute cut points for light, moderate, and vigorous activity correspond to <1952, 1952-5724, and ≥5725, and 100-2019, 2020-5998, and ≥5999, respectively. The Lopes et al cut points were developed by calibrating the ActiGraph in middle-aged and older adults with overweight/obesity and type 2 diabetes. These counts-per-minute thresholds are ≥200 (light), ≥1240 (moderate), and ≥2400 (vigorous), and were applied in 1 interventional study.ConclusionsAn assortment of accelerometer cut points have been used by researchers to categorize physical activity intensity for middle-aged and older adults with diabetes. Only one set of cut points was validated and calibrated in our population of interest. Additional research is warranted to address the need for diabetes-specific cut points to inform public health recommendations. This includes confirmation that the Lopes et al cut points reflect clinically meaningful changes in physical activity for adults with diabetes who have comorbidities other than overweight/obesity and the development of relative intensity cut points that may be more suitable for those with suboptimal physical functioning.

Project description:This study aimed to examine the validity and accuracy of wrist accelerometers for classifying sedentary behavior (SB) in children.Fifty-seven children (5-8 and 9-12 yr) completed an ~170-min protocol, including 15 semistructured activities and transitions. Nine ActiGraph (GT3X+) and two GENEActiv wrist cut points were evaluated. Direct observation was the criterion measure. The accuracy of wrist cut points was compared with that achieved by the ActiGraph hip cut point (?25 counts per 15 s) and the thigh-mounted activPAL3. Analyses included equivalence testing, Bland-Altman procedures, and area under the receiver operating curve (ROC-AUC).The most accurate ActiGraph wrist cut points (Kim; vector magnitude, ?3958 counts per 60 s; vertical axis, ?1756 counts per 60 s) demonstrated good classification accuracy (ROC-AUC = 0.85-0.86) and accurately estimated SB time in 5-8 yr (equivalence P = 0.02; mean bias = 4.1%, limits of agreement = -20.1% to 28.4%) and 9-12 yr (equivalence P < 0.01; -2.5%, -27.9% to 22.9%). The mean bias of SB time estimates from Kim were smaller than ActiGraph hip (5-8 yr: 15.8%, -5.7% to 37.2%; 9-12 yr: 17.8%, -3.9% to 39.5%) and similar to or smaller than activPAL3 (5-8 yr: 12.6%, -39.8% to 14.7%; 9-12 yr: -1.4%, -13.9% to 11.0%), although classification accuracy was similar to ActiGraph hip (ROC-AUC = 0.85) but lower than activPAL3 (ROC-AUC = 0.92-0.97). Mean bias (5-8 yr: 6.5%, -16.1% to 29.1%; 9-12 yr: 10.5%, -13.6% to 34.6%) for the most accurate GENEActiv wrist cut point (Schaefer: ?0.19 g) was smaller than ActiGraph hip, and activPAL3 in 5-8 yr, but larger than activPAL3 in 9-12 yr. However, SB time estimates from Schaefer were not equivalent to direct observation (equivalence P > 0.05) and classification accuracy (ROC-AUC = 0.79-0.80) was lower than for ActiGraph hip and activPAL3.The most accurate SB ActiGraph (Kim) and GENEActiv (Schaefer) wrist cut points can be applied in children with similar confidence as the ActiGraph hip cut point (?25 counts per 15 s), although activPAL3 was generally more accurate.

Dataset Information

Individualized Relative-Intensity Physical Activity Accelerometer Cut Points.

Purpose

Methods

Results

Conclusions

Publications

Individualized Relative-Intensity Physical Activity Accelerometer Cut Points.

Similar Datasets

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