Acute hamstring injury
Acute hamstring pain

Acute hamstring injury often occurs during exercise. Everyone knows the image of a footballer or athlete suddenly gripping the back of his thigh during a sprint. The sprint is stopped immediately and the athlete drops to the ground or limps to a halt.

In this section we describe the acute hamstring injury. If there is no obvious event at which the symptoms started, this could point to a non-acute hamstring injury.

Description of the condition

When we refer to 'hamstrings', we are actually referring to a group of 3 muscles. They are located at the back of the thigh and connect the sitting bone (ischial tuberosity) to the lower leg. The main functions are flexing the knee and extending the hip. The muscles that together form the hamstrings are called the 'semimembranosus', the 'semitendinosus' and the 'biceps femoris'.

In an acute hamstring injury, one or several fibres of a hamstring muscle will tear. The tear usually occurs at the muscle-tendon transition. These can be found at both ends of the muscle, where the rigid and sturdy tendon tissue changes to the softer muscle tissue. The muscle that is generally most often injured is the 'biceps femoris'.

A muscle tear is accompanied by bleeding. If a lot of fibres are torn, a blue, dark area can become visible at the back of the thigh. In severe cases where the entire muscle tears off, this is referred to as a complete rupture.

Cause and origin

Sprinting, getting ready to sprint or slowing down are often the moments at which symptoms can occur. Sports that involve jumping and kicking also pose an increased risk. The hamstring tear causes acute pain along the back of the thigh, after which the sports activity generally cannot be continued.

The risk of a hamstring injury during exercise increases with increasing age. In addition, there are a number of factors that increase the risk of a hamstring injury. The most important factors are: altered muscle balance, muscle fatigue, short hamstrings, inadequate warming up and previous hamstring injury.

Signs & symptoms

• Acute pain along the rear of the thigh, that generally occurs during exercise.
  
• Flexing the knee against resistance is painful. The pain can also be felt when running and sprinting.
  
• Stretching of the muscle is painful (touching the toes with the hands whilst keeping the knees straight in order to stretch the hamstrings).
  
• If a lot of fibres are torn, this can feel like a bite has been taken out of the muscle during the examination.
  
• The tear is sensitive to touch.
  
• Loss of strength.
  
• The affected muscle can contract and cause a cramping sensation.
  
• As the hamstrings attach to the sitting bones, the symptoms can also be experienced whilst sitting as this places pressure on the damaged structures.
  

If bleeding occurs, a blue, dark area can be visible along the rear of the thigh. This can be felt as a thickening of the leg. Over time, the bruise will move downwards. This is simply due to gravity.

Diagnosis

Treatment

Recovery takes an average of 6 to 8 weeks. This can be slightly shorter for a mild strain. However, a complete hamstring rupture - where the muscle tears or separates completely, will require surgery. In that case, the recovery can take up to 3 months. Surgery within a week is strongly recommended.

Following a period of rest, the muscle must be trained in a careful manner. If this does not happen correctly, the risk of a relapse is very high. The physiotherapist can guide you throughout the process, from the onset of the injury through to resuming sports activity.

The hamstring injury is a persistent injury. Even after the injury has healed, it remains a vulnerable area. Therefore, it is important to listen closely to your own body and not to carry on as normal with the symptoms.

Exercises

With an acute hamstring injury, it is important not to train too hard right away. The first phase of the injury should focus mainly on rest and light exercises. View the exercise programme here with exercises for acute hamstring injury.

You can check your symptoms using the online physiotherapy check or make an appointment with a physiotherapy practice in your area.

References
Heiderscheit, B.C., Sherry, M.A., Silder, A., Chumanov, E.S. & Thelen, D.G. (2010). Hamstring strain injuries: recommendations for diagnosis, rehabilitation and injury prevention. J Orthop Sports Phys Ther. 2010 Feb;40(2):67-81.
Hibbert, O., Cheong, K., Grant, A., Beers, A. & Moizumi, T. (2008). A systematic review of the effectiveness of eccentric strength training in the prevention of hamstring muscle strains in otherwise healthy individuals. N Am J Sports Phys Ther. 2008 May;3(2):67-81.
Petersen, J. & Hölmich, P. (2005). Evidence based prevention of hamstring injuries in sport. Br J Sports Med. 2005;39:319-323.