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

• Published in: European journal of applied physiology Vol. 106; no. 1; pp. 131 - 138
• Main Authors: Kendrick, Iain P., Kim, Hyo Jeong, Harris, Roger Charles, Kim, Chang Keun, Dang, Viet H., Lam, Thanh Q., Bui, Toai T., Wise, John A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-05-2009; Springer
• Subjects: Adult; beta-Alanine - administration & dosage; beta-Alanine - pharmacology; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Carnosine - analysis; Carnosine - metabolism; Dietary Supplements; Double-Blind Method; Fundamental and applied biological sciences. Psychology; Human Physiology; Humans; Male; Muscle Fibers, Skeletal - chemistry; Muscle Fibers, Skeletal - drug effects; Muscle Fibers, Skeletal - metabolism; Occupational Medicine/Industrial Medicine; Original Article; Osmolar Concentration; Placebos; Resistance Training; Sports Medicine; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports; Young Adult; Carnosine; Muscle; Muscle fibres; Buffering; β-Alanine; Human; Alanine; Physical training; Muscle fibres; Buffering; Supplementation; Striated muscle
• ISSN: 1439-6319; 1439-6327
• DOI: 10.1007/s00421-009-0998-5

Seven male students were supplemented with β-alanine (β-ALG) for 4 weeks (6.4 g day
−1
) and seven with a matching placebo (PLG). Subjects undertook 4 weeks of isokinetic training with the right leg (T) whilst the left leg was untrained (UT), serving as a control. Each training session consisted of 10 × 10 maximal 90° extension and flexion contractions at 180°/s using a Kin-Com isokinetic dynamometer, with 1 min rest between bouts. Muscle biopsies were taken from the
vastus lateralis
immediately before and at the end of the supplementation period. Following freeze drying muscle fibres were dissected and characterised by their MHC profile, as type I, IIa, IIx, or as hybrids of these. Carnosine was measured by HPLC. There was a significant increase in carnosine in both T and UT legs of the β-ALG (9.63 ± 3.92 mmol kg
−1
dry muscle and 6.55 ± 2.36 mmol kg
−1
dry muscle respectively). There was a significant increase in the carnosine content of all fibre phentotypes, with no significant difference between types. There were no significant differences in the changes in muscle or in fibres between the T and UT legs. In contrast there was no significant change in the carnosine content in either the T or UT legs with placebo. The results indicate that 4 weeks training has no effect on the muscle carnosine content. Whilst an increase was seen with β-alanine supplementation, this was not further influenced by training. These findings suggest that β-alanine availability is the main factor regulating muscle carnosine synthesis.