Tuesday, February 5, 2013

From CrossFit Warrior Spirit


Lufe’s Corner: Lactic Acid…Friend or Foe?

Today’s WOD (Fran) is the best example of how lactic acid works–you will feel great the first 30-50 seconds and you will be able to handle a high intensity pace. After the first 50 seconds the lactic acid will be called to action and you will be training at your lactate threshold.  The good news is that after this kind of WOD your lactate threshold will be higher and your performance more efficient.
Lactic Acid is a common concept in the world of training and fitness. It is part of a natural physiologic process when you are training, specifically in a high intensity or “anaerobic lactate threshold.” Production of lactic acid is increased with decreased oxygen availability to cells. It is not always the bad guy, because if you are well trained it could be one of your best allies to produce more energy.
The term “lactic acid” is used most commonly by athletes to describe the intense pain felt during exhaustive exercise, especially in events like the 400 meter and 800 meter sprint. When energy is required to perform exercise, it is supplied from the breakdown of Adenosine Triphosphate (ATP). The body has a limited store of about 85 grams of ATP and would use it up very quickly if we did not have ways of resynthesising it. There are three systems that produce energy to resynthesise ATP: ATP-PC, lactic acid and aerobic. Lactate, which is produced by the body all day long, is resynthesized by the liver (Cori Cycle) to form glucose that provides you with more energy.
The process of lactic acid removal takes approximately one hour, but this can be accelerated by undertaking an appropriate cool down that ensures a rapid and continuous supply of oxygen to the muscles.
Anaerobic Threshold
Lactic acid starts to accumulate in the muscles once you start operating above your anaerobic threshold. This is normally somewhere between 80% and 90% of your maximum heart rate (MHR) in trained athletes.
What a low Lactate Threshold means
If your lactate threshold (LT) is reached at low exercise intensity, it often means that the “oxidative energy systems” in your muscles are not working very well. If they were performing at a high level, they would use oxygen to break lactate down to carbon dioxide and water, preventing lactate from pouring into the blood. If your LT is low, it may mean that:
• You are not getting enough oxygen inside your muscle cells
• You do not have adequate concentrations of the enzymes necessary to oxidize pyruvate at high rates
• You do not have enough mitochondria in your muscle cells
• Your muscles, heart, and other tissues are not very good at extracting lactate from the blood
Improving your lactate threshold
The aim is to saturate the muscles with lactic acid in order to educate the body’s buffering mechanism (alkaline) to deal with it more effectively. The accumulation of lactate in working skeletal muscles is associated with fatigue of this system after 50 to 60 seconds of maximal effort. Sessions should be comprised of one to five repetitions (depends on the athlete’s ability) with near to full recovery. Training continuously at about 85 to 90% of your maximum heart rate for 20 to 25 minutes will improve your lactate threshold.
  • Warm up
  • Extended warm up: stations
    Tire flips
    Med ball cluster slams
    Hip extension (GHD)
    Kip swing
    KB skills
  • “Fran”
    Thrusters (Rx: 95/65)
    Pull ups
    *13 minute cut off
  • Cool/stretch