β-Alanine supplementation improves isometric endurance of the knee extensor muscles


Journal Title (Medline/Pubmed accepted abbreviation):J. Int. Soc. Sports Nutr.
Year: 2012
Volume: 9
First Page : 26
doi : 10.1186/1550-2783-9-26
 

Summary of background and Research Design

Background:β-Alanine is a compound that is thought to aid in performance by buffering hydrogen ions  that are produced by exercise.  In the body, β-alanine is combined with the amino acid histidine to form carnosine, a pH buffering molecule that is found in high concentrations in muscle cells.

Hypothesis: Daily β-alanine supplementation for 4 weeks will increase muscular endurance.

Subjects: Physically active, non-vegetarian males, n = 13, age 23 ± 6 y

Experimental design: randomized, placebo-controlled

Treatments : 800 mg tablets were taken 8 times per day, every 2 hours
β-alanine group: 6.4 g β-alanine per day
Control group: maltodextrin placebo

Protocol : The participants were first familiarized with the knee extension test, and their maximal voluntary isometric contraction (MVIC) was determined.  Then, before the supplementation period, they were evaluated for impulse and isometric hold time.  To do this, they completed an isometric knee extension test at 45% of their previously determined MVIC, holding for as long as possible.  Then, they consumed one of the two treatments for 4 weeks.  They were familiarized with the isometric test at the beginning of week 4, and then were evaluated at the end of week 4 for post-test data.
 

Summary of Research Findings
  • Isometric hold times were about 76 ± 18 seconds before supplementation with no difference between groups. After 4 weeks of β-alanine supplementation, hold time was increased 86.6 ± 21.9 sec. No improvement was seen in the placebo group (72.5 ± 18.5 seconds; p < 0.05).
  • Impulse values were calculated as the product of isokinetic hold time and average force held. After the supplementation period, impulse values were greater with the β-alanine group (change from baseline = 3.7 ± 1.3 kN/s) compared to the placebo group (-1.1 ± 1.5 kN/s).

Key practice applications

Supplementation with β-alanine at 6.4 g/day for one month increased the muscle capacity during isometric exercises.  This is likely due to increased buffering capacity of the muscle.  A key limitation of these findings, however, is that their relevance to any known sporting activity is questionable.
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