Muscle injuries are painful muscles level produced normally by excessive stress or external blow, usually during sports abnormalities. They are lesions that cover many types and may be ligament, joint or muscle-ligament combination muscle or ligament-articular. Triggers muscle injuries can be internal (nutrition, electrolyte balance, glycogen stores, no heating or lack of stretching), or external, due to heavy loads, repetitive movements, shock, poorly healed injuries, stances erroneous, etc. They can be classified, in turn, depending by shortening or elongation. The former include muscle inflammation delayed effect ( "stiffness"), contractures (workload in a muscle resulting in muscle rigidity) and cramps (painful and involuntary contractions of one or more muscles, being more durable than contractures and are common with fatigue). Instead, muscle injuries elongation are strains (when a muscle is subjected to overtensioning and tearing occurs), contusions (impact of a body in the muscle, and when it hits the bone causes a "bleeding" call hematoma ), fibrillar tears (fiber breakage because of the severe muscle fatigue or strong trauma), and total tears (case same as above but more serious as rupture of the muscle fibers is complete, affecting also blood) vessels.