DOI: 10.5281/zenodo.18222937
title: Physical Activity Monitoring in Older Adults (80+) in Simulated Free-Living Conditions

description: The manuscript using this dataset has been submitted to the Nordic Conference on Digital Health and Wireless Solutions 2026, and the preprint version is available at: http://arxiv.org/abs/2601.17053

This prospective observational study was conducted at the eHealth House (eHH) of the TechMed Simulation Centre, University of Twente (Enschede, The Netherlands). The eHH is a controlled environment designed to simulate free-living conditions (FLC) and includes a living room, kitchen, bedroom, and bathroom. All experimental sessions were recorded using five fixed cameras installed throughout the eHH. Participants were eligible if they were aged 80 years or older and physically able to participate independently. Individuals with cognitive impairments or mobility disorders that impede task performance were excluded. According to Dutch law, and based on a ruling from the Medical Research Ethics Committee (MREC) Arnhem–Nijmegen, the study was exempt from the Medical Research Involving Human Subjects Act. Ethical approval was granted by the Ethics Committee of the Natural Sciences and Engineering Sciences of the University of Twente. All participants provided written informed consent prior to participation.

Each participant visited the eHH once for a 75-minute session. During the visit, participants performed a set of activities of daily living (ADL) at their own pace and in their preferred order. These tasks reflected functional discharge criteria for geriatric hip fracture patients and included: (1) walking inside the eHH (between the living room, kitchen, bedroom, and front door), (2) visiting the toilet once, (3) getting in and out of bed once (sit-to-lie, lying, and lie-to-sit), (4) preparing a meal (walking to the kitchen, cutting food, and returning to the living room), and (5) preparing a drink (walking to the kitchen, pouring a drink, and returning to the living room).

Participants’ movements and postures were recorded using two wearable devices: the MOX activity monitor (Maastricht Instruments, The Netherlands) and the APDM activity tracker (Hankamp Rehab BV, The Netherlands). The MOX is a waterproof device containing a single triaxial accelerometer and was attached to the upper thigh, approximately 10 cm above the knee, using a medical plaster. Data were recorded at 25 Hz. This placement was selected based on evidence that upper-leg accelerations exhibit low inter-person variability, facilitating better generalization in HAR. The APDM comprises a triaxial accelerometer, gyroscope, and magnetometer, and was worn on the lower back using a strap. Data were recorded at 128 Hz. This location provides robust measurements of sedentary behaviors with low sensitivity to postural differences, and captures representative whole-body motion due to its proximity to the body’s center of mass. The combination of thigh and lower-back sensors was considered necessary to reliably distinguish all static and dynamic activities, as a single sensor location was insufficient.

To obtain gold-standard labels, two independent reviewers annotated the video recordings into the following activity classes: walking, standing, sitting, lying (supine, left lateral recumbent, right lateral recumbent), and transfers (stand-to-sit, sit-to-stand, sit-to-lie, and lie-to-sit). Disagreements were resolved by a third reviewer. The activity annotations were synchronized with the sensor recordings by aligning the timestamps of the first annotated sit-to-stand transfer observed in the videos with the corresponding acceleration signals.
description:  Author contributions to the collected data 

o   S.Q. led the data curation and organization for public release, coordinated the preparation of the dataset for publication, and contributed to the refinement of the associated processing scripts.

o   D. D. contributed to the experimental design and led the data collection, annotation, and processing.

o   I.H. contributed to data collection and data annotation.

o   H. H. and M. V. contributed to the experimental design and overall study conceptualization.

o   Y.W. contributed to the conceptualization and experimental design of the study, provided methodological guidance for data annotation and processing, and supervised the overall research workflow.
description: Acknowledgement:

We acknowledge Michael Bui for contributions to the initial algorithm implementation and data post-processing pipelines supporting this work.