Central fatigue during exercise: potential manuipulations and limiting factors

摘要: The development of fatigue has been an area interest to athletes and scientists alike for many years. Often, particularly during prolonged exercise in the heat, there is no obvious peripheral reason central nervous system cited as source. mechanisms potential manipulations this remain largely unclear. Chapters Three Four attempted reduce transport serotonin precursor tryptophan into brain order or delay synthesis therefore increase capacity. In Chapter branched-chain amino acid drinks were fed before cycling exhaustion heat on two occasions control other occasions. There was effect acids capacity intra-individual variability seven eight participants small. One participant did appear cycle longer trials compared trials. a 104 g bolus acids, designed deplete plasma concentration, hours heat. difference between depletion trial which also ingested. These findings suggest that delivery not only factor influencing onset fatigue. The investigation undertaken Five looked at transporter density blood platelets current retired international level competing either endurance sprint running events sedentary group. Using platelet accessible reliable model serotonergic neuron, maximum number binding sites assessed using radio-labelled reuptake inhibitor [3H]Paroxetine. Those currently training had greater than any groups. This supports previous suggests can transporters membranes. During resting exposure Six, application 1 % menthol solution skin forearms, back forehead elicited warming sensation some individuals cooling individuals, but never change core temperature nor flow. A small proportion perceive thermal sensation. Seven applied these pre-loaded twenty minute performance test It hypothesised those who perceived may perform worse when conversely, better with solution. felt significantly warmer affect their performance. However, reported tended feel cooler trial, tendency improvement trial. Due experimental protocols adopted thesis it possible assess reliability test. showed coefficient variation 11.0 ± 11.2 11.5 12.4 tests. time-trial 3.9 9.6 suggesting be more aims are still likely main choice protocol. It seems single mechanism will responsible cessation exercise. investigations highlight avenues future exploration.