Electronic Thesis and Dissertation Repository


Master of Science




Dr. John Kowalchuk


When instantaneous step-wise transitions within the moderate intensity domain are initiated from elevated metabolic rates, the rate of pulmonary oxygen uptake (V̇O2p) adjustment is slowed, and the V̇O2p gain (ΔV̇O2p /ΔWR) is greater. This study sought to determine the relationship between V̇O2p kinetics and metabolic activity and energy status during step transitions from low and elevated metabolic rates within the moderate intensity domain. Ten young men completed six double-step constant load cycling bouts, consisting of step-wise transitions from 20 W to 45% θL and 45% θL [lower step (LS)] to 90% θL [upper step (US)], one double-step bout included needle biopsies at; baseline, steady-state values and during transitions. Gas exchange was analyzed breath-by-breath and muscle de-oxygenation status ([HHb]) was measured with near infrared spectroscopy. The V̇O2p gain in the US (10.37 ± 1.49) was greater (p2p (τV̇O2p) in the US (34 ± 12) was slower (pamp in the US (3.5 ± 2.6) was decreased (pfree] and [Pi] concentration was increased (p15) and remained elevated relative to baseline through the protocol.