Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans
- 1 April 2009
- journal article
- research article
- Published by American Physiological Society in American Journal of Physiology-Regulatory, Integrative and Comparative Physiology
- Vol. 296 (4), R1078-R1087
- https://doi.org/10.1152/ajpregu.90896.2008
Abstract
We hypothesized that increasing skeletal muscle total creatine (Cr) content through dietary Cr supplementation would result in slower muscle phosphocreatine concentration ([PCr]) kinetics, as assessed using31P magnetic resonance spectroscopy, following the onset and offset of both moderate-intensity (Mod) and heavy-intensity (Hvy) exercise. Seven healthy males (age 29 ± 6 yr, mean ± SD) completed a series of square-wave transitions to Mod and Hvy knee extensor exercise inside the bore of a 1.5-T superconducting magnet both before and after a 5-day period of Cr loading (4× 5 g/day of creatine monohydrate). Cr supplementation resulted in an ∼8% increase in the resting muscle [PCr]-to-[ATP] ratio (4.66 ± 0.27 vs. 5.04 ± 0.22; P < 0.05), consistent with a significant increase in muscle total Cr content consequent to the intervention. The time constant for muscle [PCr] kinetics was increased following Cr loading for Mod exercise (control: 15 ± 8 vs. Cr: 25 ± 9 s; P < 0.05) and subsequent recovery (control: 14 ± 8 vs. Cr: 27 ± 8 s; P < 0.05) and for Hvy exercise (control: 54 ± 18 vs. Cr: 72 ± 30 s; P < 0.05), but not for subsequent recovery (control: 41 ± 11 vs. Cr: 44 ± 6 s). The magnitude of the increase in [PCr] following Cr loading was correlated ( P < 0.05) with the extent of the slowing of the [PCr] kinetics for the moderate off-transient ( r = 0.92) and the heavy on-transient ( r = 0.71). These data demonstrate, for the first time in humans, that an increase in muscle [PCr] results in a slowing of [PCr] dynamics in exercise and subsequent recovery.Keywords
This publication has 62 references indexed in Scilit:
- Phosphocreatine recovery kinetics following low- and high-intensity exercise in human triceps surae and rat posterior hindlimb musclesAmerican Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2009
- Muscle metabolic responses to exercise above and below the “critical power” assessed using31P-MRSAmerican Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2008
- Muscle [phosphocreatine] dynamics following the onset of exercise in humans: the influence of baseline work‐rateJournal Of Physiology-London, 2008
- Influence of endurance training on muscle [PCr] kinetics during high-intensity exerciseAmerican Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2007
- The mono-exponential pattern of phosphocreatine recovery after muscle exercise is a particular case of a more complex behaviourBiochimica et Biophysica Acta (BBA) - Bioenergetics, 2004
- Effect of creatine supplementation on phosphocreatine resynthesis, inorganic phosphate accumulation and pH during intermittent maximal exerciseJournal of Sports Sciences, 2002
- Effects of prior exercise on oxygen uptake and phosphocreatine kinetics during high‐intensity knee‐extension exercise in humansJournal Of Physiology-London, 2001
- Interrelations of ATP synthesis and proton handling in ischaemically exercising human forearm muscle studied by 31P magnetic resonance spectroscopyJournal Of Physiology-London, 2001
- in vivo assessment of mitochondrial functionality in human gastrocnemius muscle by 31P MRS. The role of pH in the evaluation of phosphocreatine and inorganic phosphate recoveries from exerciseNMR in Biomedicine, 1993
- First-order kinetics of muscle oxygen consumption, and an equivalent proportionality between QO2 and phosphorylcreatine level. Implications for the control of respiration.The Journal of general physiology, 1985