ANAEROBIC ENERGY SYSTEM
When the body is called upon to perform exercise at high intensities/power outputs for short durations of time (roughly 30-90 seconds) it relies heavily on the anaerobic energy system. It prefers the anaerobic system over the aerobic system because it supplies ATP (energy) at a much faster rate since it does not rely on oxygen to produce ATP. The only drawback though is the anaerobic system cannot sustain energy as long, so it fatigues at a faster rate.
The two branches of the anaerobic energy system are the lactic and alactic energy systems. I will be reviewing the lactic energy system, which is the primary energy system used in CrossFit. Below are some simple differences between the two to differentiate them:
HOW LACTIC ENERGY SYSTEM WORKS
In order for the lactic energy system to produce energy at a fast rate a chemical reaction takes place in the body that utilizes either glycogen or glucose (blood sugar). During this reaction ATP (energy) is produced rapidly, which gives us the ability to push through high intensity workouts. Unfortunately, ATP is not the only byproduct of this reaction, the other main byproducts are lactate and hydrogen ions.
THE TRUTH ABOUT LACTATE
For many years it has been believed that lactate is responsible for the burning you feel in your muscles during exercise and the soreness you feel days after an intense training session. People believed this because they thought if you trained longer and harder you would accumulate more lactic acid in your muscles. Eventually research showed though that all lactate accumulated during exercise was gone from the muscles within an hour of ending a training session, so it couldn’t have been the lactate causing the fatigue and soreness.
It was then found out that the lactate produced during high intensity training can be used as an energy source. The lactate that is accumulated in the muscles is converted into pyruvate and then into energy via the aerobic energy system. Meaning lactate is very beneficial to our ability to continuing performing during high intensity workouts, as long as you have a well trained aerobic system that can convert it into energy efficiently.
HYDROGEN, THE REAL CULPRIT
During this chemical reaction, hydrogen ions are also produced. It is these ions that lower the pH (increase the acidity) of your muscles during intense exercise that causes the deep burn you experience. When the pH is decreased it interferes with the muscles ability to contract, both forcefully and continuously. Leading to muscular fatigue and soreness following training sessions.
Now that you know the truth about lactate and that it is a very important source of energy during high intensity training. In an upcoming article, I will explain training methods that will improve your body’s ability to utilize lactate as energy, so you don’t gas out as early in workouts.
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Head Strength & Conditioning Coach at Shakopee High School