Let's get hammered

Training for an endurance event such as a marathon or Ironman requires long training runs and rides to increase aerobic capacity which typically causes us to fatigue at some point, say at mile 16 on a 20 mile run.  The muscles start getting tight and don’t seem to fire and contract like they did at mile 10.  You start slowing down, getting crankly, and your technique breaks down as well.  The last few miles seem to feel like a death march.  Which limitor is causing us to fatigue? 

I watched a very interesting webinar given by Krista Austin from Performance and Nutrition Coaching on Understanding the Limiters in Performance. She discusses the concept of neural fatigue and its role in limiting performance within the muscle.  Researchers from the Netherlands have demonstrated that fatigue occurs in the muscle when the ratio between the neurotransmitters dopamine and serotonin in the brain become unbalanced.  Dopamine and serotonin are the primary neurotransmitters responsible for exercise performance.  Serotonin can thought of as the sleepy neurotransmitter and dopamine as the excitatory neutransmitter.  

These studies showed that in well trained athletes dopamine can increase exercise performance by increasing the muscle fibers recruited while increases in serotonin levels reduces exercise capacity.  Therefore, when athletes are given dopamine agonists (enzymes helpful in producing dopamine) like the three branched chain amino acids (leucine, isoleucine, valine) and tyrosine (the precursor to dopamine) during exercise the dopamine to sertonin ratio becomes more optimal, more muscle fibers are recuited, and the the time to exhaustion is increased.  This idea of the muscle being limited by the brain itself is really fascinating.  It implies that without doing any extra training one can increase exercise performance by supplementing their nutrition with branched chain amino acids and tyrosine. 

Hammer nutrition offers the supplement Endurance Amino Acids which contains the three branched chain amino acids.  This supplementation taken during a workout of 2 or more hours may help delay central nervous system induced fatigue.  It may also help with muscle recovery and immune system function following a workout. It also recommends taking the amino acids in conjunction with their anti-fatigue caps.

I am neither advocating nor promoting this product but I am currently integrating this supplementation into my nutrition regimen as part of my current marathon training.  Thoughts and findings to follow.