The activPAL™ is currently supported across three models:
- activPAL4pro (introduced 2025)
- activPAL4 (introduced 2018, updated 2025)
- activPAL3 micro (introduced 2014, updated waterproof model 2025)
- activPAL4plus (released 2022, currently unavailable)
All the current activPAL models are 26mm wide, 43mm long, only 5mm thick and weigh 9grams (1″ x 1.7″ x 0.2″ and 0.34 ounces).
*PALpatch™ is a breathable nonwoven-polyester attachment patch with extended-wear acrylic adhesive allowing wear protocols of up to 14 days
activPAL4pro
The first natively waterproof activPAL (no jacket required), the activPAL4pro was introduced in 2025 and is recommended for new projects based on these key improvements over the activPAL4:
- Natively waterproof – no jacket required
- Reduced power consumption providing 3 weeks at 25Hz (aP4/aP3 compatible) and 50Hz recording for 14 days (aP4pro default setting)
- Updated loss-less high-fidelity data format
- Efficient data storage format delivering loss-less data files that are smaller than the equivalent activPAL4 file
- Optimized for AI applications (loss-less high-fidelity input data)
Same Great Outcomes – backwards compatible with aP3 and aP4 data formats. With a user-defined recording start delay of up to seven days, the activPAL4pro is warranted to for a minimum 14-day recording capability at 50Hz (21days at 25Hz) for the first two-years after purchase. Any activPAL failing to meet this criteria will be replaced. Refurbishment and replacement options are available for older sensors within the six-year supported lifecycle for activPAL sensors.
activPAL4
For 2025, the activPAL4 has been updated and is now natively waterproof (like the activPAL4pro – no jacket required) and so no additional protection is required for everyday immersive activities.
activPAL4 vs activPAL3
The main difference between the activPAL4 and the legacy activPAL3 is that the activPAL4 stores the acceleration sensor data as a high resolution number (10bits per sample with a range of +4 to -4g giving an 8mg resolution). It is however compatible with the activPAL3 which has a lower resolution and range (8bits per sample across a range of +2 to -2g, 16mg resolution). The activPAL4 is warranted for a minimum 14 day recording capacity (activPAL3, 7 days) for the for the first two-years after purchase. Refurbishment and replacement options are available for older sensors within the six-year supported lifecycle for activPAL sensors.
activPAL4plus (currently unavailable)
The activPAL4+ features magnetometer and barometer sensors in addition to the accelerometer sensor found in the standard activPAL. This allows us to calculate elevation (providing measures of stair ascent and descent) and direction of stepping (time and steps taken in a straight-line is a useful descriptor for the location in which the stepping activity is taking place).
The extra sensors in the activPAL4+ reduce the maximum recording duration down to around seven days with these functions enabled.
For the activPAL4+ the calculated outputs are limited in the current software release to duration of straight line stepping and height change per stepping bout. At an events level, the heading is calculated for each step and the height change in each upright event. The activPAL4+ outcomes are still in development are designed for researchers with specific project requirements at the moment. We believe activPAL4+ provides an objective measure of stair use but this has yet to be independently validated.
activPAL3 micro (legacy)
The activPAL3 micro is a legacy support version for the activPAL3 models and is maintained to provide continuity for existing projects. We recommend the activPAL4pro is selected for new projects.
activPAL family software compatibility
Current and previous activPAL models and their software suite compatibility are show below. All triaxial data files can be processed using the current version of PALanalysis and PALbatch. Users can install and use the PALsoftware to process data previously collected with obsolete and End of Life sensors as part of our life-time support commitment.
Older PALfamily members (gone but not forgotten)
activPAL™ micro, from the PALfamily of products
activPAL3 family
The activPAL3, launched in 2010, was our first triaxial activPAL and went through a number of iterations before being superceded by the smaller activPAL micro in 2014. Careful assessment should be made of the battery condition of older activPALs before use. As many of these activPALs are now more than ten years old their rechargeable batteries can be considered end-of-life. Any units with swollen cases or other evidence of battery disfunction should not be used. Due to the age of the activPAL3 family we caution against their use and recommend taking advantage of our trade-in discount offer to purchase new activPALs.
activPAL3C VT
A version of the activPAL3C that provided vibro-tactile feedback for self-monitoring of sedentary bout duration (eligible for trade-in discount against any current activPAL micro model).
activPAL3C
An update to the activPAL3, the activPAL3C introduced the distinctive curved end profile to the enclosure. The polarised enclosure has provided a signature design feature for all subsequent generations of the activPAL. The activPAL3C is eligible for trade-in discount against any current activPAL micro model.
activPAL3
The activPAL3, launched in 2010, was our first triaxial version of the activPAL (eligible for trade-in discount against any current activPAL micro model).
activPAL professional
The original activPAL was launched in 2001. The activPAL professional stored only an single axis of acceleration data and came in a replaceable primary battery version and, latterly, a rechargeable version. All activPAL professional models are eligible for trade-in discount against any current activPAL model.
We have developed products for specific project requirements, for example:
SitFIT & Activator
Developed for for self-monitoring of Physical Activity and Sedentary Behaviour. A component of the European Union funded FP7 project EuroFIT. EuroFIT was funded from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 602170.
Lower-limb prosthesis monitoring
The Long-term Activity Monitor (LAM) was designed to be fitted inside the pylon in the shank of a prosthetic limb recording limb-use on a minute by minute basis for a +12 month period.