Creatine reduces human muscle PCr and pH decrements and P_iaccumulation during low-intensity exercise

Abstract

The purpose of this study was to examine with (31)P-magnetic resonance spectroscopy energy metabolism during repeated plantar flexion isometric exercise (Ex-1-Ex-4) at 32 +/- 1 and 79 +/- 4% of maximal voluntary contraction (MVC) before and during a creatine (Cr) feeding period of 5 g/day for 11 days. Eight trained male subjects participated in the study. ATP was unchanged with Cr supplementation at rest and during exercise at both intensities. Resting muscle phosphocreatine (PCr) increased (P < 0.05) from 18.3 +/- 0.9 (before) to 19.6 +/- 1.0 mmol/kg wet wt after 9 days. At 79% MVC, PCr used, P(i) accumulated, and pH at the end of Ex-1-Ex-4 were similar after 4 and 11 days of Cr supplementation. In contrast, PCr utilization and P(i) accumulation were lower and pH was higher for exercise at 32% MVC with Cr supplementation, suggesting aerobic resynthesis of PCr was more rapid during exercise. These results suggest that elevating muscle Cr enhances oxidative phosphorylation during mild isometric exercise, where it is expected that oxygen delivery matches demands and predominantly slow-twitch motor units are recruited.

The effects of different doses of oral creatine supplementation on tibial muscle resistence and fatigue in wistar rats

“…Cr supplementation, which aims to increase PCr stocks, leads to higher ATP resynthesis capacity (GREENHAFF, 1997;TERJUNG et al, 2000;RICO-SANZ, 2000).…”

“…The effectiveness of Cr in the increase in corporal mass, performance in exercises of high intensity and exercises of short duration has been confirmed, showing it to be one of the most popular supplements in the world (BRANCH, 2003) It is believed that Cr can help the maintenance of high energy phosphate during exercise, increasing performance in several activities such as high intensity exercises, repeated tasks of intensity with frequent pauses, more prolonged anaerobic tasks, and sports activities of endurance, increasing creatine phosphate (PCr) stocks, and leading to a higher ATP resynthesis capacity (ARAÚJO et al, 2013;PERSKY;BRAZEAU, 2001;RICO-SANZ, 2000).…”

“…The protocols of Cr supplementation are varied, but studies in humans evolving Cr supplementation are usually divided into two phases: the initial phase, known as loading, with the supplementation of higher doses for 5 to 7 days, followed by, the maintenance phase, with doses reduced to 1/5 of those of the initial phase, over several weeks, for which creatine monohydrate (Crm) is the most common supplement available and used in research (RICO-SANZ, 2000).…”

Effect of free creatine therapy on cisplatin-induced renal damage

“…Several reports showed that creatine supplementation enhances oxidative phosphorylation and creatine has direct scavenger effects. [6][7][8] Guidi et al 24 reported that creatine has a protective effect on oxidatively injured mtDNA. Sestili et al 8 also reported cytoprotective effect of creatine on oxidatively injured cultured mammalian cells through direct antioxidant activity.…”

“…Creatine has been reported to have antiinflammatory, antioxidant effects and it has been shown that it acts as a free radical scavenger. [4][5][6][7][8] Besides this, recent reports supported that Cr has additional beneficial effects on various neurological, muscular, cardiovascular disorders, and aging. [9][10][11][12][13][14] The aim of this study is to investigate the possible protective effect of creatine therapy on cisplatin-induced nephrotoxicity.…”