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Effect of oral creatine ingestion on parameters of the work rate-time relationship and time to exhaustion in high-intensity cycling


Reference:

Smith, J. C., Stephens, D. P., Hall, E. L., Jackson, A. W. and Earnest, C. P., 1998. Effect of oral creatine ingestion on parameters of the work rate-time relationship and time to exhaustion in high-intensity cycling. European Journal of Applied Physiology, 77 (4), pp. 360-365.

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Official URL:

http://dx.doi.org/10.1007/s004210050345

Abstract

The relationship between work rate (overhead dot W) and time to exhaustion (t) during intense exercise is commonly described by either a hyperbolic function (NLin), t = W'/( overhead dot W - overhead dot W-cp), or by its linear equivalent (LinW) W-lim = W' + overhead dot Q-cp(t). The parameter overhead dot W-cp (critical power) has been described as an inherent characteristic of the aerobic energy system, while W' has been shown to be a rapid estimate of anaerobic work capacity. Recent studies have demonstrated that oral supplementation of creatine monohydrate (CrH-2O) increases total muscle creatine stores, and have linked these increases to improved performances in intense intermittent exercise. This study was conducted to determine the effect of CrH-2O supplementation on estimates of W' and overhead dot W-cp derived from the NLin and LinW equations, and to determine the effect of CrH-2O on t in exhaustive constant power exercise of different intensities. Fifteen active but untrained university students completed three phases of testing on a cycle ergometer: (1) familiarization, three learning trials, (2) baseline determination of W' and overhead dot W-cp, four bouts performed at a overhead dot W selected to elicit fatigue in 90-600 s, and (3) experimental determination of W' and overhead dot W-cp, four bouts performed at the same overhead dot Q as baseline, but performed after 5 days of ingesting either a placebo (4 times 6 g of glucose/day) or CrH-2O (4 times 5 g of CrH-2O and 1 g glucose/day). Testing was administered in a double-blind manner. Analyses of covariance revealed a significant effect for CrH-2O on both estimates of W' (NLin, P = 0.04; LinW, P lt 0.0 1), but not on estimates of overhead dot W-cp (NLin, P = 0.37; LinW; P = 0.30). Within groups, t was significantly different for only CrH-2O at the two highest overhead dot Ws (P = 0.04). It is concluded that oral ingestion of CrH-2O increases estimates of W' due to an improved t at the shorter, more intense exercise bouts.

Details

Item Type Articles
CreatorsSmith, J. C., Stephens, D. P., Hall, E. L., Jackson, A. W. and Earnest, C. P.
DOI10.1007/s004210050345
Uncontrolled Keywordscritical power, animals, sports medicine, (metabolism--energy and respiratory metabolism), general and miscellaneous--general), general and miscellaneous--exercise and physical therapy (1970- )), mammals, human, humans, time to exhaustion, high-intensity cycling, chordates, aerobic capacity, creatine, oral ingestion, peptides and amino acids (1972- )), primates, (nutrition--proteins, vertebrates, research article, (physiology, work rate-time relationship
DepartmentsFaculty of Humanities & Social Sciences > Health
RefereedYes
StatusPublished
ID Code30024

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