Skeletal muscle metabolism, morphology and function in master athletes

McKendry, James (2019). Skeletal muscle metabolism, morphology and function in master athletes. University of Birmingham. Ph.D.

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Abstract

Skeletal muscle mass and function deteriorates with advancing age (sarcopenia). Physical inactivity and obesity are associated with advancing age and exacerbate inherent age-related decrements in physiological function, skeletal muscle mass and morphology. The study of older individuals that have chronically undertaken structured exercise training (Master Athletes; MA) provide an opportunity to elucidate the contribution of inherent ageing and biological ageing factors to age-related physiological deterioration. Chapter 2 describes the first systematic review to quantitatively and qualitatively summarise the literature surrounding MA. We established that, at present, there are few high-quality studies, utilising sophisticated measurement tools to comprehensively assess whether, and to what extent, physiological function and muscle morphology are enhanced/preserved in MA compared with trained and untrained older and younger individuals. Accordingly, in Chapter 3, we conducted a detailed mechanistic study to compare physical function, cardiorespiratory fitness, body composition, muscle strength, architecture and fibre-type morphology in MA, with healthy untrained younger and agematched older individuals. We shed light on the morphological mechanisms through
which chronic exercise training enhances skeletal muscle function and body composition, with implications for sarcopenia diagnosis. Based on the superior phenotype observed in MA, the final experimental in this thesis, Chapter 4, describes an investigation of in vivo skeletal muscle remodelling responsiveness in MA. This work demonstrates that basal and exercise-induced rates of muscle protein synthesis are equivalent between older untrained individuals and MA. As such, untrained older individuals retain a capacity to adapt to exercise and that it may never be too late to benefit from exercise training.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):