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Aim This study investigated the effects of ageing on the excitability of soleus homonymous Ia afferents and corticospinal pathways during bipedal upright standing. Methods The input-output relations for the Hoffmann (H) reflex and motor-evoked potential ( MEP) were computed for the soleus in response to electrical nerve stimulation and transcranial magnetic stimulation, respectively, in young ( n = 16) and elderly ( n = 16) adults. In subsets of subjects, the input-output relations were compared between normal and supported upright standing, and corticomotoneuronal excitability was assessed during upright standing with an H-reflex conditioning method. For the H-reflex and MEP threshold, maximal amplitude (Hmax, MEPmax) and the slope of the input-output relation (Hslope, MEPslope) were measured and normalized to the corresponding M-wave value. Results In normal standing, the Hmax/Mmax [mean ( SD); young: 48.3 (14.2)%; elderly: 17.3 (6.4)%] and Hslope/Mslope were significantly ( P < 0.05) lower in elderly than in young adults, whereas the MEPmax/Mmax [young: 13.6 (7.5)%; elderly: 24.5 (12.8)%] and MEPslope/Mslope were greater in elderly adults ( P < 0.05). The Hslope/Mslope and MEPslope/Mslope decreased and increased, respectively, from supported to normal standing for both age groups but more so in elderly adults. Furthermore, the conditioned H reflex was greater ( P < 0.05) in elderly [175.1 (34.3)%] than in young adults [141.8 (29.8)%] during normal standing. Conclusion This is the first study that clearly indicates lower efficacy of Ia afferents to discharge spinal motor neurones accompanied by greater corticospinal excitability in elderly adults, suggesting an increased contribution of the descending drive in controlling soleus activity during upright standing with ageing. [ABSTRACT FROM AUTHOR]

The article presents a study which examined the muscle adaptation contribution in gaining maximal strength to strength training in elderly adults. The pennation angle and thickness of the gastrocnemius medialis were recorded through ultrasonography to document alterations in architecture and muscle hypertrophy. Data from both groups were being pooled together as the supplemented and placebo groups showed the same alterations in response to training for all variables.

Abstract: Aim: The aim of this paper is to review our scientific knowledge of the age-related effect on the neuromuscular system and its adaptation capacity to strength training. Current: In addition to the loss of muscle strength and mass, senescence is associated with a reduced number of motoneurones and profound motor unit remodelling. These changes have functional implications on the neural control of muscle contraction. Consequently, part of the decrease in maximal force and loss of movement accuracy that occurs with ageing can be due to an inadequate activation of the muscles by the nervous system. Fortunately, the deleterious effects of ageing on the neuromuscular system can be partly reversed by training. Conclusion: These training adaptations seem to have a positive impact on the quality of life and physical independence of the elderly population. [Copyright &y& Elsevier]