The signs of injured hamstring muscles include sharp pain in the back of the thigh, discoloration or bruising on the back of the leg, inflammation and weak muscles, according to Mayo Clinic. While mild symptoms are curable at home, an individual should visit a doctor if he experiences serious symptoms.
A hamstring injury is the pulling or straining one of the hamstring muscles, notes Mayo Clinic. It occurs when these muscles overstretch while a person undertakes a physical activity. It mostly occurs in sports players such as footballers, athletes, netballers, basketballers and dancers. Some of the factors that may predispose a person to a hamstring injury include poor flexibility, muscle imbalance and a past hamstring injury.