The muscle fiber rupture occurs because tensions during exercise with weights. This combination of factors affecting muscle and connective tissue, immediately signaled by pain nerve receptors are restored Are two important aspects:
1. Contractions eccentric (lowering phase the weight, so the elongation of the muscle under tension) produce a large amount of tension and friction intracellular (more than concentric contractions when the muscle shortens). So negative reps or greater during this portion of the next few days miscatii generates more intense muscle soreness.
2. Since muscle soreness is generated by muscle abrasions (both mechanical and chemical) that need time to heal, it is logical that a hard workout too frequently lead to trauma and older. Muscial simply will not have time to recover between two session.