Skeletal muscle metabolism during short duration high‐intensity exercise: influence of creatine supplementation

Abstract

Seven male subjects performed repeated bouts of high-intensity exercise, on a cycle ergometer, before and after 6 d of creatine supplementation (20 g Cr H2O day-1). The exercise protocol consisted of five 6-s exercise periods performed at a fixed exercise intensity, interspersed with 30-s recovery periods (Part I), followed (40 s later) by one 10 s exercise period (Part II) where the ability to maintain power output was evaluated. Muscle biopsies were taken from m. vastus lateralis at rest, and immediately after (i) the fifth 6 s exercise period in Part I and (ii) the 10 s exercise period in Part II. In addition, a series of counter movement (CMJ) and squat (SJ) jumps were performed before and after the administration period. As a result of the creatine supplementation, total muscle creatine [creatine (Cr) + phosphocreatine (PCr)] concentration at rest increased from (mean +/- SEM) 128.7 (4.3) to 151.5 (5.5) mmol kg-1 dry wt (P < 0.05). This was accompanied by a 1.1 (0.5) kg increase in body mass (P < 0.05). After the fifth exercise bout in Part I of the exercise protocol, PCr concentration was higher [69.7 (2.3) vs. 45.6 (7.5) mmol kg-1 dry wt, P < 0.05], and muscle lactate was lower [26.2 (5.5) vs. 44.3 (9.9) mmol kg-1 dry wt, P < 0.05] after vs. before supplementation. In Part II, after creatinine supplementation, subjects were better able to maintain power output during the 10-s exercise period (P < 0.05). There was no change in jump performance as a result of the creatine supplementation (P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of creatine supplementation on 800 m wheelchair performance: a pilot study

“…Possibly, the differences in total muscles mass involved during kayaking compared to wheelchair racing seemed to be of higher impact than expected and might be responsible for the reported discrepancies concerning an ergogenic effect. Moreover, lactate concentrations were not influenced by creatine supplementation in the present study, which supports the hypothesis that the glycolytic pathways were unaltered by creatine supplementation as proposed by Birch et al 2 Many studies in the past reported positive effects on performance of different types and durations after a short-term creatine supplementation, [1][2][3][4][5][6][7][8]21 whereas others found no effect. 16,[22][23][24][25][26] Interestingly, in most of the studies showing no ergogenic effect on exercise performance after creatine supplementation, a time or distance trial was performed, [22][23][24][25][26] whereas in studies with a positive effect the time to exhaustion at a given workload was determined.…”

“…Most studies investigated the influence of creatine supplementation on leg muscle performance. [1][2][3][4][5][6]8,9,16,[24][25][26] Since arm muscles contain more type II fibres than leg muscles and since type II fibres have initially a higher phosphocreatine content than type I fibres, 15 it could be hypothesised that creatine supplementation would be less efficient for arm exercise, an assumption that is supported by our findings. However, this hypotesis has to be investigated in further studies, as one cannot conclude definitely if an initially higher phosphocreatine content of arm muscles limits the effectiveness of a creatine supplementation in this muscle group.…”

“…1,7,23,30 Interestingly, one study with women only found a small, nonsignificant increase in body mass compared to placebo. 31 This could possibly be due to their smaller muscle mass.…”

“…[1][2][3][4][5][6][7][8][9] In general, enhanced performance was found in repetitive, high-intensity, short-term exercise tasks. Furthermore, creatine was successfully used also in patients with chronic heart failure, mitochondrial cytopathies and neuromuscular disease.…”

The Influence of Various Recovery Modalities on Performance Tasks in Basketball Players

“…Aside from dehydration-related fatigue, which has been firmly established [11,12], other proposed possible mechanisms focus on fluctuations in glycogen, creatine phosphate (CP), potassium, and blood lactate, but the findings have been conflicting and no single factor has been definitively linked to fatigue [5,[13][14][15][16][17][18]. There has also been increasing support for the role of the CNS and psychological factors such as motivation, experience, routines, self-belief, and perception of exertion/recovery [19][20][21][22].…”