Previous hamstring injury. People who have suffered a hamstring injury in the past are at the greatest risk of future hamstring injuries.
Muscle weakness and fatigue. If a muscle is weak or fatigued it can alter a person’s biomechanics and may increase risk of injury.
Lack of flexibility. A muscle that is less pliable may be more likely to be injured.
Inadequate warm-up. Muscles that have been warmed up will be more flexible and possibly less likely to be injured.
Muscle imbalance between the hamstrings and quadriceps. The hamstring (back of thigh) and quadriceps (front of thigh) muscle groups must work together. The risk of injury is increased if one muscle group is weaker than the other.
Dehydration. When someone is dehydrated, the muscles can be more prone to cramping and therefore more prone to injury.
Existing lower limb injury. If the body is compensating for another lower-limb injury, it can increase the chances of another injury somewhere else in the same or opposite limb.
Out of all these risk factors, a previous hamstring injury is the most significant risk factor for a recurrent hamstring injury. When compared to healthy individuals, people who have had a previous hamstring injury are 2 to 6 times more likely to suffer a hamstring injury.7,8 Because of this added risk, proper initial management and rehabilitation of an acute hamstring injury may be important to preventing future injury in an active individual.