Effect of creatine on aerobic and anaerobic metabolism in skeletal muscle in swimmers.

Abstract

Objective-To examine the effect of a relatively low dose of creatine on skeletal muscle metabolism and oxygen supply in a group of training athletes. Methods-"P magnetic resonance and near-infrared spectroscopy were used to study calf muscle metabolism in a group of 10 female members of a university swimming team. Studies were performed before and after a six week period of training during which they took either 2 g creatine daily or placebo. Calf muscle metabolism and creatine/choline ratios were studied in resting muscle, during plantar flexion exercise (10-15 min), and during recovery from exercise. Results-There was no effect of creatine on metabolite ratios at rest or on metabolism during exercise and recovery from exercise. Muscle oxygen supply and exercise performance were not improved by creatine if compared to placebo treated subjects.Conclusions-Oral creatine supplementation at 2 g daily has no effect on muscle creatine concentration, muscle oxygen supply or muscle aerobic or anaerobic metabolism during endurance exercise. (BrJ Sports Med 1996;30:222-225) We used 31p and 'H magnetic resonance spectroscopy (MRS) to examine noninvasively the effect of a longer course of a lower dose of creatine on the constituents of the creatine kinase reaction in resting and exercising skeletal muscle in a group of athletes. We coupled the MRS studies with a study of muscle reoxygenation rate using near-infrared spectroscopy (NIRS). The study was conducted in a placebo controlled fashion and the subjects were studied before and after six weeks of either placebo or creatine treatment. Methods SUBJECTSTen non-vegetarian female athletes [lean body mass 45.7 (SEM 1.1) kg] from the university swimming team were studied by 3p MRS and NIRS immediately before an eight week training period leading up to an intervarsity competition. Six weeks after the initial studies, the MRS and NIRS studies were repeated. The performance times of each subject swimming freestyle over 100 m and 400 m were recorded within one week of the MRS study.

Effects of 30 days of creatine ingestion in older men

“…Muscle wasting can lead to immobility, increased risk of falls, and disease, but maintaining a high level of physical activity may reduce such risks (Fiatarone and Evans 1993). Since Harris et al (1992) demonstrated elevated creatine (Cr) and phosphocreatine muscle levels following oral Cr monohydrate supplementation (%20 g á day A1 for 5 days), many, but not all (Barnett et al 1996;Redondo et al 1996;Terrillion et al 1997; Thompson et al 1996) investigators have shown that in young subjects, Cr has positive eects on muscle mass (Balsom et al 1993;Earnest et al 1995;Greenha et al 1994a;Vandenberghe et al 1997), strength (Earnest et al 1995;Vandenberghe et al 1997), and performance of high-intensity exercise (Casey et al 1996;Earnest et al 1995;Greenha et al 1993b;Jacobs et al 1997;Rossiter et al 1996). Only two investigations have examined the potential bene®ts of Cr supplementation in a healthy elderly population (Bermon et al 1998;Rawson et al 1998).…”

Effects of Low-Dose Creatine Monohydrate on Muscle Strength and Endurance

“…However, conflicting data with regard to the effect of creatine supplementation without a "loading phase" and using low doses exist (15)(16)(17)(18)(19). Aedma et al, in a double-blind, placebo-controlled, parallel-group study, showed that in 20 trained wrestlers whose age, weight, height, and body fat percentage were 25.6 ± 3.8 years, 82.7 ± 8.6 kg, 185.1 ± 6.5 cm, and 16.1 ± 2.4 % (mean ± SD), respectively, no improvement in upper body anaerobic power in anaerobic tests mimicking wrestling matches was observed after creatine supplementation (0.3 g/kg of body weight/day for 5 days) (19) Similarly, Wilder et al investigated creatine ergogenic effects in 25 highly trained male collegiate football players (age, 19 ± 1.02 years; height, 185.8 ± 5.27 cm; weight, 100.89 ± 21.79 kg) with at least 1 year of playing experience.…”

“…This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly cited cle endurance in subjects on low-dose creatine monohydrate supplementation (15)(16)(17)(18)(19). For example, no increase in muscle creatine concentration and no anaerobic muscle metabolism improvement were found in swimmers supplemented with 2 g of creatine per day for a period of 6 weeks (18). Similarly, 6 g/day of creatine administered for 6 days was also not sufficient to improve muscle power (Wingate test) in 40 active men (20).…”

Efeitos da suplementação de creatina no exercício intermitente de alta intensidade: divergências e recomendações metodológicas

“…Por outro lado, em atividades nas quais o peso corporal interfere no desempenho, como, por exemplo, na corrida, é possível que o trabalho adicional necessário para mover uma maior massa corporal possa reduzir os efeitos ergogênicos da suplementação de creatina. Thompsom et al 35 atribuíram ao aumento da resistência hidrodinâmica, causada pelo ganho de peso corporal, a piora do desempenho de nadadores após a suplementação de creatina (20 g/dia, por cinco dias). Por outro lado, os efeitos ergogênicos da suplementação de creatina poderiam ser suficientes para superar qualquer aumento de trabalho requerido como resultado do aumento de peso corporal.…”