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Title: Human Exercise Tolerance and the Parameters of Aerobic Function
Author: Ferguson, Carrie
ISNI:       0000 0001 3460 0360
Current Institution: University of Leeds
Date of Award: 2006
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The determinants of exercise intolerance are vital as they impinge on all individuals and are applicable across the whole spectrum of physical abili.ties. Key in this regard is the rate at which pulmonary oxygen uptake (Vo2 ) adapts to meet the energetic requirement at exercise onset, with this dependent on both the limit (i.e. v02 max) and the contour (i.e. v02 kinetics) of the v02 response. The purpose of this research was. to better understand the mechanisms. controlling v02 kinetics, and also to investigate the mechanisms determining high-intensity exercise tolerance, with specific reference to the hyperbolic power-duration (P-t) relationship. Three studies were conducted: 1. The role of 02 delivery in the control of v02 kinetics during moderate-intensity cycle ergometry. The presence of a delayed increase in deoxygenated [haemoglobin] in the region of muscle interrogation suggests that, during this delay phase, there is a dynamic balance between capillary perfusion and O2 consumption. Hence, it was \. concluded that 02 delivery is not a primary determinant of v02 kinetics, although its potential contribution under certain conditions is acknowledged. 2. Effects of supra-critical power (CP) 'priming' exercise on the profile and parameters of the P-t relationship (i.e. CP and W'J and parameters of aerobic function (i.e. the v02 time constant (rVo2 ), functional gain, lactate threshold (BJ .and Va] maJ during subsequent supra-CP exercise performed to the tolerable limit. 't vo2 , functional gain, SL, CP, v02 max were unaffected, but WI was decreased such that exercise tolerance was reduced as a predictable function of the re-define'd P-t relationship. It was concluded that WI is a key parameter of high-intensity exercise tolerance. 3. The kinetics of w' recovery, relative to ·those of v02 and blood [Lactate]. WI recovery was clearly dissociated both from that of metabolic rate and blood [Lactate], being slower compared to the former but more rapid relative to the latter. Consistent with the results of Chapter 4, exercise tolerance was reduced as a predictable function of the re-defined P-t relationship, supporting the notion that WI 'depletion' shapes high intensity exercise tolerance. Furthermore, doubt is cast on the current view that WI simply reflects a fixed 'store' of energy; rather, accumulation of fatigue-related metabolites instead may be important in defining the physiological constructs ofthis parameter.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available