Table 2.

Summary of devices to measure physical activity (PA)

Measure	Location	Data Recorded	Output	Special Notes
Accelerometers
activPal [119], a	Thigh	Time spent in sedentary behavior, standing, and walking Count of sit-to-stand transitions Total number of steps for a given period	Energy expenditure per behavior	Distinguishes between standing, sitting, and lying Differentiates various intensities of walking
Tritrac [120], b	Hip	Composite movement score (vector magnitude)	Energy expenditure per minute of movement Estimate of resting metabolic rate	Questionable validity
TracmorD [121], c	Lower back	Activity counts per minute	Total energy expenditure PA energy expenditure Physical activity level Activity energy expenditure per body mass	Waterproof Comfortable Reduces interference from spontaneous activity
Actigraph [47], d	Waist/hip	Activity counts (amplitude and frequency of acceleration over each sampling period)	Activity intensity categories Time spent in sedentary, low, moderate, and intense activity	Improves sensitivity to low intensity movement (with the Low- Frequency Extension application) Inaccurate count of steps
Pedometers
Yamax Digi- Walker [122], e	Waist	Step counts per minute	Distance travelled Total energy expenditure	Underestimates step counts at slow activity speeds Widely used in research studies
StepWatch-3 [123], f	Ankle	Step counts per minute	Distance travelled Total energy expenditure	Degree of accuracy not affected by activity speed or BMI Sensitive to small movements (e.g., fidgeting)
Heart-Rate Monitors
Polar S410 [67], g	Wrist and chest (two locations)	Beats per minute	Heart-rate per unit time Percentage of the age-based maximum heart-rate estimate Time spent in low, medium, or high intensity activity	No movement measurement
Actiheart [124–125], h	Chest (two locations)	Beats per minute Activity counts	Physical activity intensity PA energy expenditure	Combines heart-rate and movement sensors Higher noise rates in women
Arm-Band Technology
SenseWear [71], i	Upper Arm	Beats per minute Temperature	Total energy expenditure Metabolic Equivalent of Task	Objective measure of time worn Algorithms specific to vigorous activity and children

Note.

^aPAL Technologies Ltd, Glasgow, UK

^bProfessional Products, Madison, WI

^cPhilips New Wellness Solutions, Lifestyle Incubator, the Netherlands

^dActiGraph^™, Pensacola, CA

^eYamax Corporation, Tokyo, Japan

^fSW-3Ankle; Cymatech Inc., Seattle, WA

^gPolar Electro, Inc., Lake Success, NY

^hCambridge Neurotechnology, Cambridge, UK

ⁱBodyMedia, Inc., Pittsburgh, PA, USA. HealthWear (Roche Diagnostics, Indianapolis, IN) and bodybugg (Apex Fitness, San Ramon, CA) are private label versions of BodyMedia’s SenseWear technology, meaning that they can be used interchangeably with the SenseWear device.