Marjolein P. Baar's research while affiliated with University Medical Center Utrecht and other places

... Ageing is a natural, progressive and irreversible process characterized by morphological, psychological, functional, biochemical and nutritional changes (World Report on Ageing And Health, 2015). Physical inactivity (PI) is a factor that contributes to the starting of mass and muscle function decline in the elderly often related to sarcopenia and physical frailty (Lehmann, Baar, & de Keizer, 2018). Combined to protein nutritional intervention, exercise appears as an effective way to prevent muscle mass and physical fitness decline (Hernández Morante, Martínez, & Morillas-Ruiz, 2019). ...

... 1 Sarcopenic muscles are characterized by a reduction in contractile tissue mass (motor unit and fibre loss, Type II fibre atrophy) and an infiltration of other cells types (fat and connective tissue), which reduces muscle quality relative to tissue mass. 2 Although there are a number of contributing factors associated with the sarcopenic phenotype, one purported contributory mechanism is the negative effects of cellular senescence. 3 Originally demonstrated following serial passaging of cultured skin fibroblasts, 4 senescence is a phenomenon whereby cells cease to divide. It is now recognized that senescence can occur in multiple tissues, can be induced by both ageing and different stressors, and is associated with distinctive phenotypic alterations. ...