SQUATS HURT. And, they never seem to stop hurting!! Why is that?
Well, it has to do with the size of the muscle. The burn you feel while exercising is lactic acid. Lactic acid is a muscle fuel produced from glucose. This is stuff used by the mitochondria in our muscles to create power and energy. Bigger muscle = more mitochondria = the more lactic acid = more burn!
Our quadriceps are pretty big :)
For many years, it was commonly believed muscle soreness was from lactic acid buildup, but this has now been thoroughly debunked by science. The burn you feel while exercising is indeed lactic acid, however, your body flushes it out very quickly — within an hour of exercising.
The muscle soreness you experienced one to two days after exercise, is actually caused by inflammation stemming from microscopic tears in between your muscles and their surrounding tissues.
Eccentric contractions seem to cause the most soreness, meaning movements that cause your muscle to forcefully contract while lengthening, such as the downward motion of squats.
The good news is that our quadriceps are a great source of Human Growth Hormone. This hormone tells the body to burn fat for energy (you become a fat burning machine, even when sleeping) and is responsible for anti-aging things like healthier looking skin, more energy and a higher sex drive.
So, bigger muscles mean more pain but they have their benefits, too!