Why do older adults and young people move differently?

by Delft University of Technology

Joint moment during sit-to-walk for distinct arm strategies. Trajectory comparison between ARM and LEG of the (a) lumbar and (b, c) hip joint moments corrected by body weight (BW). The stepping leg is the leg that steps out first. d–f Trajectory analysis: t tests were performed for every time sample. The level of significance is visualized as the negative base-10 logarithm of the p value so that large values represent small p-values; black dashed horizontal line indicates a significant difference (p < 0.01). Credit: npj Aging (2022). DOI: 10.1038/s41514-022-00094-x

As we age, we start to change the way we move. But why do older adults and young adults move differently? How much change can we tolerate before assistance is needed? And how does adaptation relate to falls? Eline van der Kruk, researcher at the Department of BioMechanical Engineering, and a team of researchers of Imperial College London explore these questions in a study of daily life activity. Their findings were published in npj Aging.

As people get older, their movements change; older adults move differently than young adults. So what happens? Is this because they can’t move the same way as young adults? If so, which changes in their body are the most important? Or is it because they optimize for a different goal and therefore start to move differently? For example, because they are more afraid of falling. 

Eline van der Kruk and a team of researchers studied this in young and older adults in a common activity: standing up from a chair. They found that older adults that adapted their movements were not incapable of performing the same movements as the young adults. So their neuromuscular capacity did not limit them—it was the parameters related to stability and the perception that made older adults change their movements. When they get older, they therefore start to change the way they move long before there are actual physical limitations.

In Van der Kruk’s study, the researchers report on how these early adaptation strategies are of importance for early detection and prevention of falls and prolonging mobility.