Does physical inactivity accelerate skin ageing?
Based on the available studies, nothing can be said about whether physical inactivity accelerates skin ageing. If you want to know more about what influences skin ageing, look for research that specifically measures wrinkles, elasticity or skin thickness.
The available studies do not directly answer this question. None of the supplied research measures what most people mean by skin ageing: wrinkles, skin thickness, elasticity or the biological age of the skin.
What the studies do show: immobility has long been recognised as a risk factor for pressure wounds in older adults, and physical inactivity is associated with greater visceral fat (fat surrounding the organs) and insulin resistance. Whether these effects also lead to visible or measurable accelerated skin ageing is not examined in the available sources.
A mouse study measured how quickly proteins are produced in the skin of less active versus very active mice. There was no statistically significant difference. But mouse findings cannot simply be extrapolated to humans, and pressure wounds or protein synthesis are not the same as what you see as 'ageing skin'.
In short: the question of whether physical inactivity accelerates skin ageing cannot be answered using the available studies. No direct evidence was found for or against this relationship.
None of the supplied sources examines the direct relationship between physical inactivity and skin ageing (wrinkles, elasticity, skin thickness or biological skin age). The claims concern pressure wounds (PMID 1880349), visceral fat (PMID 8742584), protein synthesis in mice (PMID 33253250) and an overarching claim of insufficient evidence (PMID 34845070 and others). The question cannot be answered on the basis of these sources.