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Fuel kinetics during intense running and cycling when fed carbohydrate
On two occasions six competitive, male triathletes performed in random order, two experimental trials consisting of either a timed ride to exhaustion on a cycle-ergometer or a run to exhaustion on a motor-driven treadmill at 80% of their respective peak cycling and peak running oxygen uptakes (VO₂pe...
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| Format: | Thesis |
| Language: | English |
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MRC/UCT RU for Exercise and Sport Medicine
2018
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| _version_ | 1867613889223458816 |
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| access_status_str | Open Access |
| author | Derman, Kevin Dale |
| author2 | Hawley, John |
| author_browse | Derman, Kevin Dale Hawley, John |
| author_facet | Hawley, John Derman, Kevin Dale |
| author_sort | Derman, Kevin Dale |
| collection | Thesis |
| description | On two occasions six competitive, male triathletes performed in random order, two experimental trials consisting of either a timed ride to exhaustion on a cycle-ergometer or a run to exhaustion on a motor-driven treadmill at 80% of their respective peak cycling and peak running oxygen uptakes (VO₂peak)- At the start of exercise, subjects drank 250 ml of a 15 g.100 ml⁻¹ w.v⁻¹ glucose solution with U-¹⁴C glucose added as tracer and, thereafter, 150 ml of the same solution every 15 min. Despite identical metabolic rates (VO₂ 3.51 ±0.06 vs. 3.51 ±0.10 l.min⁻¹; values are mean± SEM for the cycling and running trials, respectively), exercise times to exhaustion were significantly longer during cycling than running (96 ±14 vs. 63 ±11 min; P<0.05). The superior cycling than running endurance was not associated with any differences in either the rate of blood glucose oxidation (3.8 ±0.1 vs. 3.9 ±0.4 mmol.min⁻¹ ), nor the rate of ingested glucose oxidation (2.0 ± 0.1 vs. 1.7 ±0.2 mmol.min⁻¹) at the last common time point (40 min) before exhaustion, despite higher blood glucose concentrations at exhaustion during running than cycling (7.0 ±0.9 vs. 5.8 ±0.5 mmol.l⁻¹; P<0.05). However, the final rate of total CHO oxidation was significantly greater during cycling than running (24.0 ±0.8 vs. 21.7 ±1.4 mmol C6 .min⁻¹;P<0.01). At exhaustion, the estimated contribution to energy production from muscle glycogen had declined to similar extents in both cycling and running (68 ±3 vs. 65 ± 5%). These differences between the rates of total CHO oxidation and blood glucose oxidation suggested that the direct and/or indirect (via lactate) oxidation of muscle glycogen was greater in cycling than running. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/26976 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:43:19.116Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2018 |
| publishDateRange | 2018 |
| publishDateSort | 2018 |
| publisher | MRC/UCT RU for Exercise and Sport Medicine |
| publisherStr | MRC/UCT RU for Exercise and Sport Medicine |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/26976 Fuel kinetics during intense running and cycling when fed carbohydrate Derman, Kevin Dale Hawley, John Bicycling Dietary Carbohydrates - pharmacology Energy Metabolism Exercise Running On two occasions six competitive, male triathletes performed in random order, two experimental trials consisting of either a timed ride to exhaustion on a cycle-ergometer or a run to exhaustion on a motor-driven treadmill at 80% of their respective peak cycling and peak running oxygen uptakes (VO₂peak)- At the start of exercise, subjects drank 250 ml of a 15 g.100 ml⁻¹ w.v⁻¹ glucose solution with U-¹⁴C glucose added as tracer and, thereafter, 150 ml of the same solution every 15 min. Despite identical metabolic rates (VO₂ 3.51 ±0.06 vs. 3.51 ±0.10 l.min⁻¹; values are mean± SEM for the cycling and running trials, respectively), exercise times to exhaustion were significantly longer during cycling than running (96 ±14 vs. 63 ±11 min; P<0.05). The superior cycling than running endurance was not associated with any differences in either the rate of blood glucose oxidation (3.8 ±0.1 vs. 3.9 ±0.4 mmol.min⁻¹ ), nor the rate of ingested glucose oxidation (2.0 ± 0.1 vs. 1.7 ±0.2 mmol.min⁻¹) at the last common time point (40 min) before exhaustion, despite higher blood glucose concentrations at exhaustion during running than cycling (7.0 ±0.9 vs. 5.8 ±0.5 mmol.l⁻¹; P<0.05). However, the final rate of total CHO oxidation was significantly greater during cycling than running (24.0 ±0.8 vs. 21.7 ±1.4 mmol C6 .min⁻¹;P<0.01). At exhaustion, the estimated contribution to energy production from muscle glycogen had declined to similar extents in both cycling and running (68 ±3 vs. 65 ± 5%). These differences between the rates of total CHO oxidation and blood glucose oxidation suggested that the direct and/or indirect (via lactate) oxidation of muscle glycogen was greater in cycling than running. 2018-01-25T13:54:42Z 2018-01-25T13:54:42Z 1996 Master Thesis Masters MSc (Med) http://hdl.handle.net/11427/26976 eng application/pdf MRC/UCT RU for Exercise and Sport Medicine Faculty of Health Sciences University of Cape Town |
| spellingShingle | Bicycling Dietary Carbohydrates - pharmacology Energy Metabolism Exercise Running Derman, Kevin Dale Fuel kinetics during intense running and cycling when fed carbohydrate |
| thesis_degree_str | Master's |
| title | Fuel kinetics during intense running and cycling when fed carbohydrate |
| title_full | Fuel kinetics during intense running and cycling when fed carbohydrate |
| title_fullStr | Fuel kinetics during intense running and cycling when fed carbohydrate |
| title_full_unstemmed | Fuel kinetics during intense running and cycling when fed carbohydrate |
| title_short | Fuel kinetics during intense running and cycling when fed carbohydrate |
| title_sort | fuel kinetics during intense running and cycling when fed carbohydrate |
| topic | Bicycling Dietary Carbohydrates - pharmacology Energy Metabolism Exercise Running |
| url | http://hdl.handle.net/11427/26976 |
| work_keys_str_mv | AT dermankevindale fuelkineticsduringintenserunningandcyclingwhenfedcarbohydrate |