How to calculate Physical Activity from captured .CWA files?


Accelerometers have been used for estimating occurrence and frequency of various patterns in free-living data. There is no simple "one fits all" solution when it comes to analysis, however, there are best practices, validated methods and previous work. Axivity sensors log RAW data. This means it is possible to trial and compare a variety of methods as well as re-processing in the future (should other methods become available).


We have generated a compiled list of previous approaches that might make it easier to identify the best currently available method.


Alternatively, in the OMGUI software (v1.24 onwards), an option to export a CSV file containing epoch summary measures, wear time validation, cut-point threshold PAEE is available.


Other resources that might be useful are:
  • Third party, Matlab pre-processing scripts to help use in energy expenditure/physical activity calculations.
  • An open source R package developed by Vincent van Hees to assist with accelerometry processing.
  • An assortment of third party Matlab scripts for use with CWA binary data.