Properties of the vastus lateralis muscle in relation to age and physiological function in master cyclists aged 55–79 years

Abstract

SummaryIn this study, results are reported from the analyses of vastus lateralis muscle biopsy samples obtained from a subset (n = 90) of 125 previously phenotyped, highly active male and female cyclists aged 55–79 years in regard to age. We then subsequently attempted to uncover associations between the findings in muscle and in vivo physiological functions. Muscle fibre type and composition (ATPase histochemistry), size (morphometry), capillary density (immunohistochemistry) and mitochondrial protein content (Western blot) in relation to age were determined in the biopsy specimens. Aside from an age‐related change in capillary density in males (r = −.299; p = .02), no other parameter measured in the muscle samples showed an association with age. However, in males type I fibres and capillarity (p < .05) were significantly associated with training volume, maximal oxygen uptake, oxygen uptake kinetics and ventilatory threshold. In females, the only association observed was between capillarity and training volume (p < .05). In males, both type II fibre proportion and area (p < .05) were associated with peak power during sprint cycling and with maximal rate of torque development during a maximal voluntary isometric contraction. Mitochondrial protein content was not associated with any cardiorespiratory parameter in either males or females (p > .05). We conclude in this highly active cohort, selected to mitigate most of the effects of inactivity, that there is little evidence of age‐related changes in the properties of VL muscle across the age range studied. By contrast, some of these muscle characteristics were correlated with in vivo physiological indices.

Superior Aerobic Capacity and Indices of Skeletal Muscle Morphology in Chronically Trained Master Endurance Athletes Compared With Untrained Older Adults

“…Nevertheless, it is clear from our results that chronic endurance exercise training leads to greater MHC I and II fibre capilliarisation in MA compared with OC and, in some cases, YC. These findings are consistent with recent evidence that the continuation of endurance training into older age maintains skeletal muscle capilliarisation47 .However, recent evidence from a cross-sectional analysis of highly trained MA (55-79 y)suggests that chronic endurance training does not completely prevent the decline in capillary density12 . Nevertheless, the greater muscle fibre capilliarisation and MHC I fibre area observed in our cohort of endurance-trained MA may, at least partly, explain their superior aerobic fitness levels.Whilst our findings clearly demonstrate superior indices of physiological function and muscle morphology in MA compared with OC, we are unable to determine whether chronic endurance exercise offsets the trajectory of age-related physiological deterioration.…”

The Inherent Human Aging Process and the Facilitating Role of Exercise

“…Will the same physiological index value suffice for a 70-year-old exerciser and a 70-year-old inactive person? The available data indicate probably not ( Wilson and Tanaka, 2000 ; Pollock et al, 2018 ). We have previously discussed the issue regarding the relationship (or lack of) between age and function across multiple physiological indices ( Lazarus and Harridge, 2010 , 2011 ; Harridge and Lazarus, 2017 ).…”

From discoveries in ageing research to therapeutics for healthy ageing

“…Although much hope and investment are currently focused on drug development, it is important to note that exercise behaves as a true and effective geroprotector. In the absence of suitable treatments for agerelated dysfunction, exercise is currently the only intervention that has shown a remarkable efficacy for reducing the incidence of age-related disease 171,172 , improving the quality of life 173 and even increasing mean and maximum lifespan in humans 174,175 . Its benefits can be seen even with modest implementation 173 .…”