B-Alanine Flashcards
(15 cards)
What is the product of beta-alanine and L-histidine in the body?
Carnosine
In what sporting scenarios a) event length b) predominant energy pathway c) fatigue experienced does beta-alanine reliably benefit performance?
For Beta-alanine to have an ergogenic effect on performance activity must be…
a) 1-7 mins long
b) anaerobic glycolysis makes up a substantial contribution to energy requirements
c) metabolic acidosis is the main limiting factor and cause of fatigue (the “burn” is experienced)
What is the mechanism by which beta-alanine supplementation benefits exercise performance?
increases muscular conc of carnosine which acts as a intracellular buffer of hydrogen ions produced from anaerobic glycolysis.
How does anaerobic glycolysis cause fatigue?
formation of lactic acid (lactate + H ions). H ions build up and lower muscle pH (acidosis), interfering w/ muscle contraction process.
How does beta-alanine benefit performance when anaerobic glycolysis is the main energy pathway?
H ion buffer, reducing muscle fatigue.
Enables athlete to generate more ATP from anaerobic glycolysis before an equivalent level of fatigue is reached.
Power output can be maintained longer.
Why not just take carnosine instead of beta-alanine?
Ingesting carnosine doesn’t increase muscle conc of carnosine as it’s broken down in the GI tract and intestinal absorption is poor.
Are there any negative side effects of Beta-alanine supplementation in the
a) short term (acute use) - reference
b) long term (chronic use)
a) excessive doses (>800 mg) have been shown to cause paraesthesia (pins and needles) - Harris et al (2006)
b) Little evidence into long term (>10 weeks) supplementation, so can’t confirm, however, doses are similar to those in naturally high diets so unlikely.
What is the optimal dosing for beta-alanine supplementation and why?
- 2 - 6.4 g/day, taken in small doses throughout the day to avoid negative side effect of paraesthesia.
- Harris et al (2006)
Supplementation of 3.2-6.4 g/day of beta-alanine over 4-10 weeks results in what change to muscular conc of carnosine?
Increased 60-80%
- Harris et al (2006)
Are there any cross-over benefits to supplementing beta-alanine with anything else?
- give the reference and describe the study/findings
Hoffman et al
B-A+Cr over 10 weeks of resistance training in college football players.
B-A+Cr resulted in no sig greater strength and power gains compared w/ Cr only.
B-A+Cr resulted in sig greater body comp changes, down to increased training volume.
How strong is the evidence into beta-alanine supplementation benefiting
a) muscle carnosine conc.
b) performance
a) very strong and well accepted
b) not iron clad, but pretty strong.
Should beta-alanine be supplemented acutely or chronically?
chronically
Why may the support of study’s into the ergogenic benefits of beta-alanine not be top notch?
-reference
many studies try to observe the effects of beta-alanine on activities not producing sufficient levels of muscular acidosis.
Those that observe multiple bouts of short, high int exercise, single high-int exercise >60 s and power tests when fatigue is already present (all extremely acidotic environments) consistently show benefit to performance.
- Artioli et al (2009)
What is another limitation of lots of the evidence into beta-alanine supplementation that may give it low ecological validity when looking at elite athletes?
much of the research is into ‘untrained’ individuals. Highly anaerobically trained athletes have shown greater muscle carnosine levels than untrained or endurance athletes.
Studies into athletes may, therefore, show lower effects of beta-alanine supplementation
Give an example of a study showing no benefit of beta-alanine supplementation on performance that had poor methodology.
Derave et al
4 week B-A supplementation.
no benefit of B-A on 400 m time or maximal isometric knee extension to exhaustion.
400 m lasts <60 s and leg ext was 45 degrees, not obstructing blood flow enough. Neither activity created an acidotic enough environment for the buffering benefits of increased muscle carnosine conc.
