Activity of group III-IV muscle afferents: implication for the neuromuscular and cardiovascular responses to exercise in humans

Zambolin, Fabio ORCID: https://orcid.org/0000-0002-4178-6965 (2023) Activity of group III-IV muscle afferents: implication for the neuromuscular and cardiovascular responses to exercise in humans. Doctoral thesis (PhD), Manchester Metropolitan University.

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Abstract

Changes in activation of muscle III-IV afferents has shown to lead to impaired cardiovascular and neuromuscular responses to exercise. The mechanisms underlying these alterations has been attributed to changes in sensitivity of the muscle afferents that associated with muscle inflammation, ageing and pathological conditions. In the first three experimental chapter (chapter 4 to 6), we collected data from healthy moderately active young male performing an exercise induced muscle damage protocol (EIMD), that induced muscle inflammation and changes in muscle afferent activation (i.e., mechano and nociceptors) 48h post EIMD. These changes were associated to alterations in blood pressure regulation, cardiovascular responses, peripheral blood flow, neuromuscular function, and exercise performance. Following these experiments, we tested the association of blood pressure responses and exercise performance in a master athletes’ cohort (Chapter 7), showing links between increased blood pressure responses and lower exercise performance. In the last chapter (chapter 8), we conducted a systematic review with meta-analysis to determine cardiorespiratory fitness and neuromuscular function of people with Chronic fatigue and Fibromyalgia syndromes compared to healthy individuals. From the 99 studies selected we found a large decreased in cardiorespiratory fitness, neuromuscular function, and fatigability within increased in perceived exertion in patients. In conclusion, the data collected showed the physiological relevance of the changes in muscle afferents activation, becoming relevant for future studies in chronic pain and fatigue conditions.