Muscle burning pain appears to be the sign of lactic acid activity in muscles. Is the following situation familiar to you: you perform numerous Barbell Curls and your arms start burning; it becomes so painful that you have to stop doing the exercise? Why does it happen? Is lactic acid our fried or foe?
You should remember that muscles can restore their energy supply by different means: both using oxygen (aerobic way) and without it (anaerobic way) when glycogen supply turns into ATP molecules that our organism requires. Exactly this way leads to lactic acid production performed by our muscles. In a normal state of our organism lactic acid is removed from muscles with the help of blood rather quickly; during workout, however, the bloodstream in an engaged muscle is hampered (blood is pumped in the muscle and doesn’t leave it); and lactic acid can remain in the engaged muscle for long enough to cause burning sensation.
Lactic acid is synthesized from lactate anion and hydrogen (acid) that reduces pH level and causes this burning sensation. This is a very rapid process; as soon as we stop training our pH level returns to its normal state and painful burning disappears.
It is possible for our muscles to produce lactic acid in large quantities and don’t feel its painful manifestations but this can happen only if blood circulation is not hampered (and it’s almost impossible during active workout session). The rule is rather simple: the more blood we pump into our muscles the more muscle burning pain sensation is; less blood – less pain (it’s a direct dependence). I suppose, many of you will agree with this statement when you recollect your own ‘pumping’ trainings. This kind of trainings is the most vivid example of painful influence of lactic acid.
Bodybuilders know that low-reps power workout method doesn’t lead to muscle burning pain and actively use it. There is one more way to avoid active effect of lactic acid – to use the Rest Pause Training method. During 10-20 seconds of rest intervals the major part of lactic acid is removed from our muscles and burning is significantly reduced.
There is a well-known myth about muscles lactic acid: lots of people consider it the reason of after-training muscle pain. But this is not true. In reality, the most part of lactic acid is removed from muscles right after we stop performing a hard exercise and the rest part – within one hour after a training session. The more active our rest is the more quickly this process takes place. At the same time, the pain that you feel after your workout is explained by muscle micro-injuries gained during hard work. The more intensive your workout is the stronger after-training pain will be.
Now, I suppose, it’s clear that muscle burning pain sensation during a workout session will not lead obligatory to after-training pain and muscle growth. One can perform exercise with very light weights that are not enough to damage muscle fibers but are enough to cause muscle burning.
What is muscles lactic acid for?
Our organism uses it as an energy source for glucose and glycogen synthesis. When you workout intensively 75% of lactic acid produced in ‘quick’ muscle fibers moves to ‘slow’ ones and serves as their energy ‘fuel’. That’s why active rest after a training session (‘slow’ fibers are active) will assist quicker removal of lactic acid from muscles than passive one.
Lactic acid is a very important energy source because it allows us to workout intensively to achieve muscle growth.