• Running or sprinting is a common cause of hamstring injuries.Image by Flickr.com, courtesy of Hamed Saber
  
  

Function

• The hamstring muscles cross and influence two joints. According to the Nicholas Institute of Sports Medicine and Athletic Trauma (www.nismat.org), the hamstring causes the knee to bend and the thigh to move backward. It is a major factor in people being able to walk, run and jump.
  
  

Injury

• Hamstring injuries are common, especially in athletics. They can be very painful. The severity of the injury can vary from mild to severe strains of the muscles to tears. Symptoms include sudden or severe pain in the back of the thigh area during exercise, sometimes accompanied by a popping sound
  
  

Causes

• According to WebMD, during a strain, the hamstring muscles get tight and are stretched too far. They even start to tear. Running or jumping causes the injury, especially if you don't properly warm up. Teenagers going through a growth spurt are more susceptible to the injury.
  
  

Healing

• Rest and stretching are vital to healing minor strains, according to Mayo Clinic physical medicine and rehabilitation specialist Edward R. Laskowski, M.D. Strengthening exercises will help prevent a recurrence of the injury. More severe injuries or tears may require surgery. "A pulled hamstring, or any other muscle strain, can take from two to six weeks to heal, depending on the severity of the injury," Laskowski says (www.mayoclinic.com).
  
  

Avoiding Injury

• There's no way to eliminate the risk of hamstring injury, but you can reduce your risk by strengthening and stretching your leg muscles before physical activity. According to the Nicholas Institute, "A gradual conditioning program, specific to your sport, will prepare the hamstrings for the high demands placed upon them during athletics."
  
  

Sports

• Basketball and other sports that involve sprinting and jumping see frequent hamstring injuries.Image by Flickr.com, courtesy of Lauren Nelson
  
  While a hamstring injury can occur when you are out for a walk or a light jog, mild to severe strains are common in sports that involve sprinting activities, including track and field, football and basketball. According to www.sportsinjury.net, athletic trainers and sports injury specialists work to avoid and rehabilitate injuries by using massage techniques and providing specific stretching exercises.