Challenges and Solutions for Measuring Physical Activity

[This article has been written by Joren Buekers and Sarah Koch, postdoctoral researchers at ISGlobal]

January is typically the time of the year when we promise ourselves that we will be more physically active. To keep track of our physical activity levels, many choose to observe their daily step count, minutes spent walking or kilocalories burned, based on measurements provided by smartphones or physical activity trackers, including sport- or smart-watches.

Did you know that measuring physical activity involves several challenges and limitations, particularly in individuals whose gait differs from the norm?

Did you know that measuring physical activity involves several challenges and limitations, particularly in individuals whose gait differs from the norm?

Firstly, smartphones and physical activity trackers primarily focus on physical activity markers that are relatively easy to estimate, such as daily step count. It goes without saying that step count is an adequate marker for walking-related physical activities (including jogging or running), but it is less representative for other daily-life physical activities, such as household chores or biking. This should be kept in mind when interpreting the various physical activity markers (for example, kilocalories burned) provided by our smartphones or physical activity trackers.

Secondly, the algorithms used for calculating walking-related physical activity markers are mostly developed and tested in laboratory settings, while walking in the real world provides extra challenges such as activities of a very short duration, turning around, stepping sideways, uneven walking surfaces and steep terrain. Therefore, more research is needed to better understand how well these laboratory-derived algorithms perform in the real world.

Thirdly, these often-proprietary algorithms are developed using data from young individuals with a healthy gait. As a result, the algorithms might not perform as well for individuals whose gait differs from the norm, for example, due to shuffling, gait imbalances between the left and right foot, or very small steps at a high cadence with sudden freezing periods. Gait that differs from the norm can have many causes, such as a hip fracture or non-communicable diseases that affect the neurological system (for example, Parkinson’s disease) or respiratory system (for example, chronic obstructive pulmonary disease (COPD)). These conditions are major contributors to global morbidity and mortality, and heavily rely on physical activity in their treatment approach to enhance and maintain patients’ quality of life, mobility and general well-being.

Mobilise-D to Enhance Measurements of Physical Activity

The goal of the Mobilise-D consortium, of which ISGlobal is a partner, is to tackle the challenges of:

1. Adequately measuring physical activity

2. During daily life

3. In individuals whose gait differs from the norm

Researchers from ISGlobal together with experts from European universities, hospitals, industry partners and affected patients are therefore developing algorithms that allow the assessment of daily-life physical activity in patients with Parkinson’s disease, multiple sclerosis, hip fracture and COPD. The goal is that these algorithms can be used on any physical activity tracker instead of being specific to a certain brand or type of wearable device.

Researchers from ISGlobal together with experts from European universities, hospitals, industry partners and affected patients are developing algorithms that allow the assessment of daily-life physical activity in patients with Parkinson’s disease, multiple sclerosis, hip fracture and COPD

Additionally, the Mobilise-D project wants to unravel how characteristic symptoms and markers that describe the severity of the aforementioned conditions are linked with alterations in physical activity and gait. For example, we aim to better understand how lung function in patients with COPD is related to their walking speed during daily-life activities. A better understanding of these relationships could provide a new avenue for monitoring the progression of one’s condition based on measurements of physical activity and gait during daily-life routines.

Before we can examine and interpret these relationships, we need to know how physical activity and gait are generally altered in different conditions. While these alterations are well-documented for Parkinson’s disease and multiple sclerosis, it is still unclear for patients with COPD. Therefore, at ISGlobal we are working on an additional, in-depth analysis on how patients with COPD actually walk in both a laboratory setting and during daily life, and how this differs from healthy peers.

Interested in Learning More About the Challenges and Solutions for Measuring Physical Activity and Gait?

Starting on 2 February 2022, the Mobilise-D consortium will be hosting a first series of five webinars (twice a month from February to April 2022) on the generation and validation of algorithms to assess physical activity in individuals whose gait differs from the norm. Additional webinars on a variety of topics related to Mobilise-D will be organised on a monthly basis afterwards. Everyone is invited to participate.

Please follow this link to find more information and registration details.