So I was on the stationary bike in spin class the other night at the Central Y in Gastonia, NC and the instructor said to sprint to flush the lactic acid out of our calf muscles after performing a set of intervals.
I had always heard that lactic acid was the bad guy: that it makes your muscles burn and causes you to feel sore the next day after a workout. I got to thinking and did a little research to learn that it is essentially wrong. In fact, it's the fuel for your muscles. It's produced by converting carbohydrates into lactate which is then used by your muscles whether they be in your limbs, torso or your heart.
So what causes the fatigue in your muscles? There's no good answer but one theory is your muscles, once exhausted, leak calcium and this weakens your muscle contractions, thus causing them to fatigue.
So contrary to popular belief, lactic acid is our friendly fuel source, not the arch enemy of the runner, cyclist or professional athlete. Who would've known?
When runner's excessively pronate (roll their arches inward), the extra energy expended by their leg muscles can cause them to fatigue more easily. Excessive pronation can be controlled by the use of foot orthotic devices. By controlling the pronation, the muscles function more efficiently.
