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The Effect Of Beta-alanine And Creatine Monohydrate Supplementation On Muscle Composition And Exercise Performance

2005; Lippincott Williams & Wilkins; Volume: 37; Issue: Supplement Linguagem: Inglês

10.1097/00005768-200505001-01832

1530-0315

Chester A. Hill, Roger C. Harris, Hyojeong J. Kim, L. Boobis, Craig Sale, John A. Wise,

Diet and metabolism studies

Carnosine (Carn) is found predominantly in type II muscle fibres contributing to H+ buffering and possibly to increased Ca2+ sensitivity. Carn is synthesised in muscle from Beta-Alanine (ß-Ala) and Histidine (His) of which ß-Ala is limiting. ß-Ala is obtained from in-vivo ex-muscle synthesis and meat ingestion. We have previously reported a 64% increase in Carn with 4 weeks ß-Ala supplementation. PURPOSE To investigate if ß-Ala supplementation affects the capacity to undertake intense exercise in comparison to, and in combination with, creatine monohydrate (CrM) supplementation. METHODS Forty male subjects [mean (SD)] aged 25.2 (6.6) yrs; height 1.79 (0.07) m; mass 76.5 (11.3) kg were assigned to receive A) ß-Ala (4.0g. d-1 during week 1 increasing to 6.4g.d−1 at week 4), B) ß-Ala (same dose) and 20g.d-1 CrM during week 4, C) Placebo or D) 20g.d−1 CrM during week 4. In groups A and B, 6 of the 10 subjects continued ß-Ala supplementation until 10 weeks; additionally CrM was given during week 10 in groups B and D. Work done (WD) during cycling to exhaustion at 110% of previously estimated 'power max' was measured at 0, 4 and 10 weeks using an SRM ergometer. Biopsies of the v. lateralis were taken at these times from 4x6 subjects and analysed for Carn and total creatine (TCr). RESULTS Mean (SE) muscle Carn, prior to supplementation, was 23.62 (1.02) mmol.kg−1.dm. The mean (SE) changes following 4 & 10 weeks supplementation were A: +13.82 (1.15) & +17.16 (1.33), and, B:+1 1.86 (0.69) & +17.34 (1.03) mmol.kg−1.dm. Carn was unchanged in groups C and D. TCr was increased in groups B and D but was unchanged in groups A and C. Initial WD of all subjects was 55.49 (1.84 kJ). The mean (SE) changes (kJ) after 4 & 10 weeks supplementation were A:+8.13(0.81) & +8.86 (1.71); B: +6.07 (0.89) & +9.77 (1.29); C: −0.75 (0.25) & -0.59 (0.31): D: +6.28 (1.51) & +7.26 (1.93). Groups A, B and D completed significantly more work than group C (P<0.05) at 4 weeks. There was no significant difference between groups A, B and D. CONCLUSION Work done was significantly increased with ß-Ala and CrM supplementation, although the effects did not appear to be additive. Supported by research grant from NAI, San Marcos, Ca, USA