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Owen Spendiff and Ian G. Campbell

Seven athletes with low lesion paraplegia ingested a 7.6% 648ml glucose drink using two schedules of ingestion (4 × 162 ml per 20 min & 2 × 324 ml per 60 min) in a crossover design. Participants exercised at 65% peak oxygen uptake for one hour, followed by a 20-minute performance test. The cardiorespiratory responses during the one-hour tests were similar between trials. Plasma glucose concentrations significantly increased after ingestion and remained stable during the 162 trial, but reduced over time during the 324 trial. Free fatty acid concentrations increased for both trials but increased significantly more during the 324 trial. The results of this study suggest that the ingestion of glucose during exercise is the best strategy for wheelchair athletes competing in endurance events.

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Owen Spendiff and Ian G. Campbell

Eight men with spinal cord injury ingested glucose (CHO) or placebo (PLA) 20-min prior to exercise. Participants performed arm crank ergometry for one-hour at 65% V̇O2peak, followed by a 20-min performance test in which athletes were asked to achieve their greatest possible distance. Physiological responses during the one-hour tests were similar between CHO and PLA trials. At the onset of exercise, the CHO trial blood glucose concentrations were higher than PLA (p < .05) but returned to resting values after 20-min exercise. Respiratory exchange ratio responses during the CHO trial were indicative of a higher rate of CHO oxidation (p < .05). A greater distance (km) was covered in the 20-min performance tests after CHO ingestion (p < .05). Results show preingestion of glucose improves endurance performance of wheelchair athletes.

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David J. Muggeridge, Christopher C. F. Howe, Owen Spendiff, Charles Pedlar, Philip E. James and Chris Easton

The aim of the current study was to determine the effects of dietary nitrate ingestion on parameters of submaximal and supramaximal exercise and time trial (TT) performance in trained kayakers. Eight male kayakers completed four exercise trials consisting of an initial discontinuous graded exercise test to exhaustion and three performance trials using a kayak ergometer. The performance trials were composed of 15 min of paddling at 60% of maximum work rate, five 10-s all-out sprints, and a 1 km TT. The second and third trials were preceded by ingestion of either 70 ml nitrate-rich concentrated beetroot juice (BR) or tomato juice (placebo [PLA]) 3 hr before exercise using a randomized crossover design. Plasma nitrate (PLA: 33.8 ± 1.9 μM, BR: 152 ± 3.5 μM) and nitrite (PLA: 519.8 ± 25.8, BR: 687.9 ± 20 nM) were higher following ingestion of BR compared with PLA (both p < .001). VO2 during steady-state exercise was lower in the BR trial than in the PLA trial (p = .010). There was no difference in either peak power in the sprints (p = .590) or TT performance between conditions (PLA: 277 ± 5 s, BR: 276 ± 5 s, p = .539). Despite a reduction in VO2, BR ingestion appears to have no effect on repeated supramaximal sprint or 1 km TT kayaking performance. A smaller elevation in plasma nitrite following a single dose of nitrate and the individual variability in this response may partly account for these findings.