frAGILE: does function follow form in young and old adults in immobilization and retraining?

Phases of immobilization are accompanied by a loss of muscle strength. Initial data show that these losses are i) greater in older men than in young men and ii) greater in young women than in young men. The project now aims to investigate why the different effects occur and how a period of re-training affects these losses.

Content and objectives of the research project

Immobilization results in a decline in physical function, even over short durations. This decline can hinder everyday activities, such as walking, particularly in seniors experiencing age-related physical deterioration. Preliminary findings suggest that the impact of immobilization and the recovery process varies by age and gender. Specifically, (i) young women appear to be more affected than young men, and (ii) older men show greater performance losses compared to their younger counterparts. The underlying reasons for these disparities remain uncertain.

This study therefore aims to explore the underlying mechanisms that can explain the age- and gender-specific differences. Four groups - young men, young women, older men, and older women - will participate in a 10-day immobilization of one leg, followed by three weeks of rehabilitation training. The investigation will focus on physical functions such as strength, balance, and gait, as well as the mechanisms underlying potential differences between groups. Advanced research methods will be employed to assess muscle activity, the interplay between the nervous system and muscles, and tendon properties.

Scientific and social context of the research project

This study aims to shed light on how immobilization and re-training affect different groups, which is important in view of the ageing world population. The inclusion of different genders is fundamental, as it is not possible to draw conclusions from studies with a specific group (e.g. young men) to the population as a whole. For example, there is currently no data on immobilization effects in old women, which this study will change.