The Carnosine Content of Vastus Lateralis Is Elevated in Resistance-Trained Bodybuilders

Abstract

Resistance training is associated with periods of acute intracellular hypoxia with increased H(+) production and low intramuscular pH. The aim of this study was to investigate the possible adaptive response in muscle carnosine (beta-alanyl-L-histidine) in bodybuilders. Extracts of biopsies of m. vastus lateralis of 6 national-level competitive bodybuilders and 6 age-matched untrained but moderately active healthy subjects were analyzed by high-performance liquid chromatography. Significant differences were shown in carnosine (p < 0.001) and histidine (p < 0.05). Muscle carnosine in bodybuilders was twice that in controls. The carnosine contents measured are the highest recorded in human muscle and represent a 20% contribution to muscle buffering capacity. Taurine was 38% lower in bodybuilders, though the difference was not significant. Possible causes for the changes observed are prolonged repetitive exposure to low muscle pH, change of diet or dietary supplement use, or the use of anabolic steroids. The increase in buffering capacity could influence the ability to carry out intense muscular activity.

Muscle Carnosine Metabolism and β-Alanine Supplementation in Relation to Exercise and Training

“…Although the extragonadal sexual dimorphism in mice is more pronounced than in humans, there is indirect evidence supporting a role for androgens in carnosine synthesis. In a descriptive study on bodybuilders, where substance abuse with anabolic steroids is not unusual, very high muscle carnosine concentrations (approximately twice as high as in a control population) have been reported [72]. Also the well-described decline in androgen concentration with advancing age may be a determinant of the lower carnosine content of old muscle.…”

Effects of Beta-Alanine Supplementation on Sprint Endurance

“…Hill et al (15) suggested that carnosine may contribute less than 10% to the total buffering capacity of human muscle whereas other authors have reported carnosine contributing up to 20% (36).…”

“…Carnosine levels are higher in sprint athletes and bodybuilders compared to marathon runners and sedentary individuals (36). In order to determine whether or not beta-alanine supplementation itself actually increases carnosine levels, it is important to consider the training status of the subjects or measure carnosine concentrations at the start of the study.…”

“…Tallon et al (36) examlned the carnoslne concentrations in the vastus lateralis of resistance trained bodybuilders. The bodybuilders had participated in bodybullding at least 5 yrs wlth an average of 8 hrs of trainlng per week.…”

The effect of 4 weeks β-alanine supplementation and isokinetic training on carnosine concentrations in type I and II human skeletal muscle fibres

“…Tallon et al (2005) found carnosine contents of 43 mmol kg ¡1 dry muscle in samples of vastus lateralis from experienced bodybuilders, whilst Kim et al (2005) reported concentrations of 34 mmol kg ¡1 dry muscle in elite Korean speed skaters. Both postulated that regular exposure to extreme skeletal muscle acidosis brought about an up-regulation in carnosine synthesis to increase its content 1.5-2 fold.…”