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Accepted for/Published in: JMIR Bioinformatics and Biotechnology

Date Submitted: Apr 6, 2022
Open Peer Review Period: Apr 5, 2022 - May 31, 2022
Date Accepted: Jul 7, 2022
(closed for review but you can still tweet)

The final, peer-reviewed published version of this preprint can be found here:

Monitoring Physical Behavior in Rehabilitation Using a Machine Learning–Based Algorithm for Thigh-Mounted Accelerometers: Development and Validation Study

Skovbjerg F, Honoré H, Mechlenburg I, Lipperts M, Gade R, Næss-Schmidt ET

Monitoring Physical Behavior in Rehabilitation Using a Machine Learning–Based Algorithm for Thigh-Mounted Accelerometers: Development and Validation Study

JMIR Bioinform Biotech 2022;3(1):e38512

DOI: 10.2196/38512

PMCID: 11135216

Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.

Monitoring physical behavior in rehabilitation - Developing and validating a machine learning-based algorithm for thigh mounted accelerometers.

  • Frederik Skovbjerg; 
  • Helene Honoré; 
  • Inger Mechlenburg; 
  • Matthijs Lipperts; 
  • Rikke Gade; 
  • Erhard Trillingsgaard Næss-Schmidt

ABSTRACT

Background:

Physical activity (PA) is emerging as an outcome measure. Accelerometers have become an important tool in monitoring physical behavior and newer analytical approaches of recognition methods increase the degree of details.

Objective:

The purpose of this study was to develop and validate an algorithm for classifying several daily physical behaviors using a single thigh-mounted accelerometer and a supervised machine learning scheme.

Methods:

We collected training data for adding further behavior classes to an existing algorithm. Combining data, we were potentially able to classify 11 behaviors, using a Random Forest learning scheme. We validated the algorithm through a simulated free-living procedure using chest-mounted cameras for establishing the ground truth. Furthermore, we adjusted our algorithm and compared the performance with a validated algorithm.

Results:

In the simulated free-living validation, the performance of the algorithm decreased to 64% as a weighted average for the 11 classes (F-measure). After reducing to 5 classes corresponding with the validated algorithm, the result revealed high performance in comparison with both the ground truth and the validated algorithm.

Conclusions:

We developed an algorithm to classify 11 physical behaviors. We obtained high classification levels within specific behaviors, while others yielded lower classification potential.


 Citation

Please cite as:

Skovbjerg F, Honoré H, Mechlenburg I, Lipperts M, Gade R, Næss-Schmidt ET

Monitoring Physical Behavior in Rehabilitation Using a Machine Learning–Based Algorithm for Thigh-Mounted Accelerometers: Development and Validation Study

JMIR Bioinform Biotech 2022;3(1):e38512

DOI: 10.2196/38512

PMCID: 11135216

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