par Carpentier, Alain ;Poortmans, Jacques
Référence Science & Sports, 24, page (74-78)
Publication Publié, 2009
Article révisé par les pairs
Résumé : Aims: Sarcopenia, a reduction in muscle mass, is intimately linked to ageing, but as well to a deficient-protein intake and a reduced physical-activity level. This implies frailty, motor instability, limited-physical performance, more dependence towards other people and more medical-care costs. Current knowledge: Several metabolic dysfunctions are related to a reduction of muscle mass. Primarily, it seems that protein synthesis is reduced while proteolysis is increased. Muscle-protein synthesis depends on adequate amino acids intake, but also to the action of several signals inducing the activation of new protein molecules; anabolic hormones, neuronal impulses, muscle-membrane signals. Protein degradation is linked to the activation of signal cascades induced by excess calcium and reactive-oxygen species: capsases and ubiquitin systems mainly. Prospects: Regular physical training involving strength exercise attenuates the muscle-mass reduction by enhancing protein synthesis, particularly during the early phase of recovery with essential amino-acids supply, enriched with leucine. © 2008 Elsevier Masson SAS. All rights reserved.