The primary aim of this dissertation was to examine the effects of creatine (Cr) supplementation on exercise performance, body mass, muscle phosphocreatine (PCr), and blood Cr in older men. The effect of acute (20 g of Cr d −1 for 5 d, preliminary study) and longer term (20 g of Cr d −1 for 10 d followed by 4 g of Cr d−1 for 20 d, Study I) Cr supplementation on isokinetic leg fatigue, maximal isometric force (MIF), and body mass was examined in healthy older men (60–82 yr) over two studies. In both the preliminary study and Study I there was a small improvement on the isokinetic leg fatigue test, but this did not achieve statistical significance. There was no effect of the Cr supplement on MIF. In the preliminary study there was a small (0.5 kg) increase in body mass in the Cr group after supplementation, but in Study I this difference was not statistically significant between groups. In Study II, the effects of Cr supplementation on muscle PCr, blood Cr, urine Cr, and urine creatinine (Cn) were assessed in eight young (20–32 yrs) and seven old (63–83 yrs) male subjects who ingested Cr (20 g d −1) for 5 days. Plasma Cr, following a 5 gram oral Cr bolus, increased, with no difference in the response between groups. Urine Cr, assessed pre and on five days of supplementation, increased, with no difference between groups. Urine Cn did not change as a result of Cr supplementation. Muscle PCr, assessed pre- and post-supplementation increased significantly more in the young subjects. Data from the preliminary study and Study I suggest that acute and longer term oral Cr supplementation does not affect MIF and only produces small increases in body mass and performance on an isokinetic leg fatigue test in men over the age of 60. The smaller increase in muscle PCr in the older subjects in Study II may explain the lack of a significant ergogenic effect of Cr in this population.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-3437 |
| Date | 01 January 2000 |
| Creators | Rawson, Eric S |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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