What Causes Muscle Soreness? Fitstep.com Home -> Advanced Training -> Advanced Tips -> What Causes Muscle Soreness Most weight trainers do not know the reason their muscles get sore after a workout. Muscle soreness is not caused by lactic acid, as many people believe. It is caused by microtrauma to the muscle fibers. This causes calcium molecule leakage from the muscle fibers (as well as an accumulation of histamines, potassium, prostaglandins and local edema). The sensation of pain and soreness comes due to the pressure of localized edema (fluid retention) on nerve endings, not by the muscle damage itself. Negative-accentuated training often results in severe muscle soreness as it causes the most muscle damage. Muscle soreness can be an indication of growth. Light training of the same exercise can help decrease it. It is possible to train when the muscle is sore.   "I have to say I was greatly impressed with your book and I enjoyed the variations of the different exercises. I coach professional Rugby players and from a point of using these exercises for stability as well as functional purposes, I found them good as did the players." - S. Mitchell Click here for more information   Return To Advanced Training Tips Index