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DAPA Measurement Toolkit

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The GT3X+ is an accelerometer manufactured by Actigraph (Pensacola, Florida, USA) released in 2010.

The device uses a capacitive triaxial Microelectro-Mechanical-System (MEMS) accelerometer which records accelerations with dynamic range ±6 g. The sampling rate is user defined at 10 Hz increments between 30 Hz to 100 Hz. Th device also collects ambient light data in Lux at a sampling rate of 1 Hz.

Battery life and storage capacity are dependent upon sampling rate (e.g. 22.5 days battery and 42.5 days memory at 30 Hz with 24 hour continuous activity).

Output is available in both the pre-filtered raw format (g), and in propietary activity counts at a user defined epoch derived using Actilife software, also produced by Actigraph. The device also uses data from all three axes to distinguish different postures (non-wear, standing, lying, sitting). Data from the verical axis are used to estimate step counts.

The GT3X+ features a Low Frequency Extension option, which increases sensitivity to very low amplitude activities allowing for the study of population groups who move slowly or take very light steps (for example, the elderly).

The device is attached to the body using a strap and can be attached at a variety of wear locations, for example the wrist, waist, arm or ankle.

Component Detail
Sample Rate 30-100 Hertz
Battery Life 30 days
Axes 3
Weight 19 g
Size 46 mm * 33 mm * 15 mm
Memory 512 MB
Battery life 31 days
Dynamic range ±6 g
Output variable Units
Acceleration g
ActiGraph counts Counts per user defined epoch (e.g. counts per minute)
Steps Steps per user defined epoch (e.g. steps per minute)
Posture 1) Device off; 2) Standing; 3) Lying; 4) Sitting
Resource Link
User guide External site (PDF)
Firmware External site
ActiLife Software External site
Lifestage Reliability and validity literature
Adults External site
Infants External site
Older adults External site
First author (year) Title
Brazendale et al. (2017) External site