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The effects of prior oral creatine supplementation on performance and metabolism after 7 days of sprint cycle training
Oral creatine supplementation has been shown to increase skeletal muscle total creatine (TCr) content, and in some cases improve performance in high-intensity short duration exercise. A variety of factors related to an enhanced efficacy of adenine nucleotide metabolism have been demonstrated as part...
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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_ | 1867613295832203264 |
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| access_status_str | Open Access |
| author | Bold, Antoinette |
| author2 | Myburgh, Kathryn Helen |
| author_browse | Bold, Antoinette Myburgh, Kathryn Helen |
| author_facet | Myburgh, Kathryn Helen Bold, Antoinette |
| author_sort | Bold, Antoinette |
| collection | Thesis |
| description | Oral creatine supplementation has been shown to increase skeletal muscle total creatine (TCr) content, and in some cases improve performance in high-intensity short duration exercise. A variety of factors related to an enhanced efficacy of adenine nucleotide metabolism have been demonstrated as partly responsible for this ergogenic effect. Also, there is evidence that high-intensity sprint training results in a decrease in muscle total adenine nucleotide (TAN) and/or ATP stores. This placebo controlled double-blind study examined whether an oral creatine supplementation regimen would 1) increase muscle TCr content, 2) attenuate any loss in TAN or ATP during intermittent sprint training, and 3) have an ergogenic effect on performance after sprint training. Thirteen male endurance trained cyclists ingested 20 g of creatine monohydrate supplement or placebo per day for 7 days, after which they ingested a maintenance dose of 2 g creatine or placebo per day for the remainder of the trial (15d). While on the maintenance dose, subjects performed intermittent sprint training (ST) on a cycle ergometer (10 x 10 s sprints with 140 s active recovery) for 6 consecutive days and a 7th day after one day of rest. Performance tests were performed before and after ST, and metabolic tests were performed on the 1st and 7th day of ST. TCr increased significantly with creatine supplementation (creatine group pre: 121 ± 4, post: 147 ± 9; vs. placebo group pre: 122 ± 4, post: 125 ± 4 mmol/kg dm; mean± SEM; p<0.05). The increase in TCr correlated with the percentage Type IIB fibres (r=0.95, p<0.005). By day 7 of ST, TCr content was no longer significantly higher than pre-supplementation levels despite the maintenance dose of creatine. ST resulted in a significant decrease in resting muscle TAN and ATP content in both groups (ATP content in creatine group pre: 24.1 ± 0.8, post: 17.2 ± 0.5; and placebo group pre: 26.5 ± 1.1, post: 18.0 ± 0.6 mmol/kg dm; p<0.001). During and in recovery from ST on day 7, both groups had lower plasma ammonia (p<0.05), hypoxanthine (p<0.001) and urate (p<0.001) accumulation than on day 1 of ST. There was no improvement in 1-hr cycle distance performance after ST, but peak sustained power output increased in the creatine group and not in the placebo group after ST (p<0.05). Peak and mean power during a 30 s Wingate test increased significantly (p<0.05) after ST but there was no additional ergogenic effect of creatine supplementation. In conclusion, this study shows that 1) the efficacy of muscle creatine uptake was dependent on the percentage of Type IIB fibres, 2) creatine supplementation and maintenance (2 g/d) did not attenuate ATP or TAN loss during 7 days of ST, 3) ST decreased the accumulation of plasma products of adenine nucleotide degradation and improved 30 s sprint performance, and 4) creatine supplementation and ST did not improve I-hr cycle distance performance. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/26974 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:33:51.607Z |
| 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:11427/26974 The effects of prior oral creatine supplementation on performance and metabolism after 7 days of sprint cycle training Bold, Antoinette Myburgh, Kathryn Helen Exercise Science Creatine Creatine - metabolism Exertion - physiology Oral creatine supplementation has been shown to increase skeletal muscle total creatine (TCr) content, and in some cases improve performance in high-intensity short duration exercise. A variety of factors related to an enhanced efficacy of adenine nucleotide metabolism have been demonstrated as partly responsible for this ergogenic effect. Also, there is evidence that high-intensity sprint training results in a decrease in muscle total adenine nucleotide (TAN) and/or ATP stores. This placebo controlled double-blind study examined whether an oral creatine supplementation regimen would 1) increase muscle TCr content, 2) attenuate any loss in TAN or ATP during intermittent sprint training, and 3) have an ergogenic effect on performance after sprint training. Thirteen male endurance trained cyclists ingested 20 g of creatine monohydrate supplement or placebo per day for 7 days, after which they ingested a maintenance dose of 2 g creatine or placebo per day for the remainder of the trial (15d). While on the maintenance dose, subjects performed intermittent sprint training (ST) on a cycle ergometer (10 x 10 s sprints with 140 s active recovery) for 6 consecutive days and a 7th day after one day of rest. Performance tests were performed before and after ST, and metabolic tests were performed on the 1st and 7th day of ST. TCr increased significantly with creatine supplementation (creatine group pre: 121 ± 4, post: 147 ± 9; vs. placebo group pre: 122 ± 4, post: 125 ± 4 mmol/kg dm; mean± SEM; p<0.05). The increase in TCr correlated with the percentage Type IIB fibres (r=0.95, p<0.005). By day 7 of ST, TCr content was no longer significantly higher than pre-supplementation levels despite the maintenance dose of creatine. ST resulted in a significant decrease in resting muscle TAN and ATP content in both groups (ATP content in creatine group pre: 24.1 ± 0.8, post: 17.2 ± 0.5; and placebo group pre: 26.5 ± 1.1, post: 18.0 ± 0.6 mmol/kg dm; p<0.001). During and in recovery from ST on day 7, both groups had lower plasma ammonia (p<0.05), hypoxanthine (p<0.001) and urate (p<0.001) accumulation than on day 1 of ST. There was no improvement in 1-hr cycle distance performance after ST, but peak sustained power output increased in the creatine group and not in the placebo group after ST (p<0.05). Peak and mean power during a 30 s Wingate test increased significantly (p<0.05) after ST but there was no additional ergogenic effect of creatine supplementation. In conclusion, this study shows that 1) the efficacy of muscle creatine uptake was dependent on the percentage of Type IIB fibres, 2) creatine supplementation and maintenance (2 g/d) did not attenuate ATP or TAN loss during 7 days of ST, 3) ST decreased the accumulation of plasma products of adenine nucleotide degradation and improved 30 s sprint performance, and 4) creatine supplementation and ST did not improve I-hr cycle distance performance. 2018-01-25T13:54:32Z 2018-01-25T13:54:32Z 1996 Master Thesis Masters MSc http://hdl.handle.net/11427/26974 eng application/pdf MRC/UCT RU for Exercise and Sport Medicine Faculty of Health Sciences University of Cape Town |
| spellingShingle | Exercise Science Creatine Creatine - metabolism Exertion - physiology Bold, Antoinette The effects of prior oral creatine supplementation on performance and metabolism after 7 days of sprint cycle training |
| thesis_degree_str | Master's |
| title | The effects of prior oral creatine supplementation on performance and metabolism after 7 days of sprint cycle training |
| title_full | The effects of prior oral creatine supplementation on performance and metabolism after 7 days of sprint cycle training |
| title_fullStr | The effects of prior oral creatine supplementation on performance and metabolism after 7 days of sprint cycle training |
| title_full_unstemmed | The effects of prior oral creatine supplementation on performance and metabolism after 7 days of sprint cycle training |
| title_short | The effects of prior oral creatine supplementation on performance and metabolism after 7 days of sprint cycle training |
| title_sort | effects of prior oral creatine supplementation on performance and metabolism after 7 days of sprint cycle training |
| topic | Exercise Science Creatine Creatine - metabolism Exertion - physiology |
| url | http://hdl.handle.net/11427/26974 |
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