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Rate of force development is Ca2+-dependent and influenced by Ca2+-sensitivity in human single muscle fibres from older adults.
Mazara, Nicole; Zwambag, Derek P; Noonan, Alex M; Weersink, Erin; Brown, Stephen H M; Power, Geoffrey A.
Afiliación
  • Mazara N; Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, Ontario, Canada; School of Kinesiology, Faculty of Education, University of British Columbia, Vancouver, British Columbia, Canada.
  • Zwambag DP; Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, Ontario, Canada.
  • Noonan AM; Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, Ontario, Canada.
  • Weersink E; Health and Performance Centre, Sports Medicine Clinic, University of Guelph, Guelph, Ontario, Canada.
  • Brown SHM; Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, Ontario, Canada.
  • Power GA; Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, Ontario, Canada. Electronic address: gapower@uoguelph.ca.
Exp Gerontol ; 150: 111348, 2021 07 15.
Article en En | MEDLINE | ID: mdl-33862138
Natural adult aging is associated with declines in skeletal muscle performance, including impaired Ca2+ sensitivity and a slowing of rapid force production (rate of force redevelopment; ktr). The purpose of this study was to investigate the relationship between impaired Ca2+ sensitivity and ktr of single muscle fibres from young and older adults. Participants included 8 young (22-35 yrs) and 8 older (60-81 yrs) males who were living independently. A percutaneous muscle biopsy of the vastus lateralis of each participant was performed. Single muscle fibre mechanical tests included maximal Ca2+-activated force (Po), force-pCa curves, and ktr. We showed a decrease in pCa50 in old type II fibres compared to young, indicating impaired Ca2+ sensitivity in older adults. The ktr behaved in a Ca2+-dependent manner such that with increasing [Ca2+], ktr increases, to a plateau. Interestingly, ktr was not different between young and old muscle fibres. Furthermore, we found strong associations between pCa50 and ktr in both old type I and type II fibres, such that those fibres with lower Ca2+ sensitivity had a slowed ktr. This Ca2+ association, combined with impaired Ca2+ handling in older adults suggests a potential Ca2+-dependent mechanism affecting the transition from weakly- to strongly-bound cross-bridge states, leading to a decline in skeletal muscle performance. Future research is needed to explore the role alterations to Ca2+ sensitivity/handling could be playing in age-related whole muscle performance declines.
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Texto completo: 1 Bases de datos: MEDLINE Asunto principal: Calcio / Contracción Muscular Tipo de estudio: Diagnostic_studies Límite: Aged / Humans / Male Idioma: En Revista: Exp Gerontol Año: 2021 Tipo del documento: Article País de afiliación: Canadá

Texto completo: 1 Bases de datos: MEDLINE Asunto principal: Calcio / Contracción Muscular Tipo de estudio: Diagnostic_studies Límite: Aged / Humans / Male Idioma: En Revista: Exp Gerontol Año: 2021 Tipo del documento: Article País de afiliación: Canadá