Comparing Five Generations of ActiGraph Devices using an Orbital Shaker.

Introduction: ActiGraph accelerometers are used extensively to objectively assess physical activity, sedentary behavior, and sleep. Here, we present an objective validation of five generations of ActiGraph sensors to characterize potential differences in output arising from changes to hardware or firmware.

Methods: An orbital shaker generated accelerations from 0 to 3700 milli-g in a randomized order to test the wGT3X-BT, GT9X, CentrePoint Insight Watch (CPIW) 1.

A CNN Model for Physical Activity Recognition and Energy Expenditure Estimation from an Eyeglass-Mounted Wearable Sensor.

Metabolic syndrome poses a significant health challenge worldwide, prompting the need for comprehensive strategies integrating physical activity monitoring and energy expenditure. Wearable sensor devices have been used both for energy intake and energy expenditure (EE) estimation. Traditionally, sensors are attached to the hip or wrist.

The use of accelerometers to improve estimation of the thermic effect of food in whole room calorimetry studies.

We tested whether spontaneous physical activity (SPA) from accelerometers could be used in a whole room calorimeter to estimate thermic effect of food (TEF). Eleven healthy participants ( = 7 females; age: 27 ± 4 yr; body mass index: 22.8 ± 2.

Deep phenotyping of post-infectious myalgic encephalomyelitis/chronic fatigue syndrome.

Post-infectious myalgic encephalomyelitis/chronic fatigue syndrome (PI-ME/CFS) is a disabling disorder, yet the clinical phenotype is poorly defined, the pathophysiology is unknown, and no disease-modifying treatments are available. We used rigorous criteria to recruit PI-ME/CFS participants with matched controls to conduct deep phenotyping. Among the many physical and cognitive complaints, one defining feature of PI-ME/CFS was an alteration of effort preference, rather than physical or central fatigue, due to dysfunction of integrative brain regions potentially associated with central catechol pathway dysregulation, with consequences on autonomic functioning and physical conditioning.

Does Wrist-Worn Accelerometer Wear Compliance Wane over a Free-Living Assessment Period? An NHANES Analysis.

Purpose: Accelerometers are used to objectively measure physical behaviors in free-living environments, typically for seven consecutive days or more. We examined whether participants experience "wear fatigue," a decline in wear time day over day, during typical assessment period acquired in a nationally representative sample of 6- to 80-yr-olds in the United States.

Methods: Participants were instructed to wear an ActiGraph GT3X+ on their nondominant wrist continuously for seven consecutive days.

Evaluating the Performance of Sensor-based Bout Detection Algorithms: The Transition Pairing Method.

Unlabelled: Bout detection algorithms are used to segment data from wearable sensors, but it is challenging to assess segmentation correctness.

Purpose: To present and demonstrate the Transition Pairing Method (TPM), a new method for evaluating the performance of bout detection algorithms.

Methods: The TPM compares predicted transitions to a criterion measure in terms of number and timing.

Discrimination of wear and non-wear in infants using data from hip- and ankle-worn devices.

Introduction: A key component to analyzing wearable sensor data is identifying periods of non-wear. Traditionally, strings of consecutive zero counts (e.g.

Challenges and opportunities related to the objective assessment of physical activity within U.S. health surveys.

Public health surveillance is a vital component in the assessment of health-related behaviors such as physical activity (PA). With multiple active national health surveys in the United States, questions arise about how data are collected, what each data source contributes to the overall knowledge base about PA and health outcomes, and how to interpret PA data from different data sources to gain an understanding about PA at the population level. This article highlights specifically the challenges and opportunities with using wearable devices in population-level PA assessment.

Youth Metabolic Equivalents Differ Depending on Operational Definitions.

Unlabelled: Youth metabolic equivalents (METy) are sometimes operationally defined as multiples of predicted basal metabolic rate (METyBMR) and other times as multiples of measured resting metabolic rate (METyRMR).

Purpose: This study aimed to examine the comparability of METyBMR and METyRMR.

Methods: Indirect calorimetry data (Cosmed K4b) were analyzed from two studies, with a total sample of 245 youth (125 male participants, 6-18 yr old, 37.

Accuracy of the Cosmed K5 portable calorimeter.

Purpose: The purpose of this study was to assess the accuracy of the Cosmed K5 portable metabolic system dynamic mixing chamber (MC) and breath-by-breath (BxB) modes against the criterion Douglas bag (DB) method.

Methods: Fifteen participants (mean age±SD, 30.6±7.

Use of consumer monitors for estimating energy expenditure in youth.

The purpose of this study was to compare energy expenditure (EE) estimates from 5 consumer physical activity monitors (PAMs) to indirect calorimetry in a sample of youth. Eighty-nine youth (mean (SD); age, 12.3 (3.

Use of Objective Measures to Estimate Sedentary Time in Youth.

The purpose of the study was to conduct a comprehensive evaluation of the ActiGraph GT3X+ (AG) and activPAL (AP) for assessing time spent in sedentary behaviors (SB) in youth using structured and free-living activities. Forty-four participants (mean±SD; age, 12.7±0.

Estimating Energy Expenditure with ActiGraph GT9X Inertial Measurement Unit.

Purpose: The purpose of this study was to explore whether gyroscope and magnetometer data from the ActiGraph GT9X improved accelerometer-based predictions of energy expenditure (EE).

Methods: Thirty participants (mean ± SD: age, 23.0 ± 2.

Step Counting: A Review of Measurement Considerations and Health-Related Applications.

Step counting has long been used as a method of measuring distance. Starting in the mid-1900s, researchers became interested in using steps per day to quantify ambulatory physical activity. This line of research gained momentum after 1995, with the introduction of reasonably accurate spring-levered pedometers with digital displays.

StepWatch accuracy during walking, running, and intermittent activities.

Introduction: The purpose of this study was two-fold: 1) to investigate effects of cadence and sensitivity settings for the StepWatch (SW3) on step count accuracy over a wide range of ambulatory speeds, and 2) to compare the preprogrammed "quick start" settings to modified settings during intermittent lifestyle activities.

Methods: Part 1: Fifteen participants (18-57 years of age) performed two trials of treadmill walking and running at ten speeds ranging from 26.8 to 268mmin while wearing four SW3 devices.