Hamstring strains are known to be one of the most common sporting injuries, associated mostly with sports that involve high-speed running (rugby, football, cricket, athletics etc).
The hamstrings are three muscles in the posterior thigh; biceps femoris, semitendinosus and semimembranosus.
Muscles strains can be classified into three grades dependent on severity of the injury, similar to the grading system seen for ligamentous injuries (see our blog on acute lateral ankle sprains for more information).
Grade 1 – The muscle or tendon is overstretched potentially producing small tears to muscle fibres, leading to mild pain with or without swelling
Grade 2 – A moderate muscle strain where there is greater stretching of the muscle or its tendon resulting in greater tearing to muscle fibres but not a complete rupture. The area of injury may be tender, bruising will occur if small blood vessels at the site of injury are damaged and swelling may also be present. Grade 3 – A severe muscle strains where most or all of the muscle fibres are torn/damaged. Pain, swelling, tenderness and bruising will most likely be present and movement will be difficult.
More recently other proposals have been made to change the classification system so that it can improve the management of muscle injuries. The first change proposed that muscle injuries be classified into direct injuries or indirect injuries, (see this link for a table that explains this more simply than I can!).
The other proposed change involved a grading system of 0-4 depending on the grade of injury based on findings from MRI. This can then be further broken down using either a, b or c as a suffix to determine the area of the muscle injured
(myofascial, musculo-tendinous or intra-tendinous respectively).
Epidemiology (who is affected)
Hamstring muscle injuries are most commonly associated with anyone who is physically active, especially participating in activities that involves high-speed running such as rugby, football, cricket, athletics etc.
Hamstring strains can affect anyone but there are risk factors that include your likelihood of injury such as:
History of injuries including major knee injury and osteitis pubis
Higher level of competition
Playing in the later stages of matches/fatigue (particularly football and rugby)
Muscle imbalances (overdeveloped quadriceps compared to hamstrings)
Poor warm up or cool down
There are other risk factors, that are more associated with re-injury including:
Aetiology (the cause)
The cause of hamstring strains are classified into two separate categories.
Type 1 – Related to sprinting or heavy loading of the hamstrings as can be seen when sprinting, jumping or kicking. This type is most commonly seen just before the heel strikes the ground in the gait cycle, due to the large amount of load placed on the hamstrings as they are approaching their maximum length.
Type 2 – Considered as stretch related injuries and are seen more commonly in sports such as dance or gymnastics due to the excessive stretch positions taken up in the sports. These can feel less intense than type 1 but can also take longer to heal.
Management and rehabilitation
Initial management during the acute phase 48-72 hours after injury should involve RICE protocol (Rest, Ice, Compression, Elevation).
Rest – To protect from worsening the injury or to prevent further injury
Ice – To provide pain relief and reduce excessive swelling (placed indirectly to skin through a wrap or sleeve to the area of injury every 2 hours)
Compression – To reduce excessive swelling
Elevation – To improve blood flow and to reduce excessive swelling further
Medical help should be seen for a muscle injury to help classify the injury. This will help to identify a complete muscular rupture (that will likely involve further medical attention that a manual therapist can’t provide i.e. surgical re-attachment). It will also help identify if your symptoms are caused by referred pain.
Initially weight-bearing and strain should be avoided until excessive pain has subsided.
As pain subsides, exercise and activity are slowly re-integrated to promote healing in the injured muscle and to help identify and help any relevant contributors to the injury (i.e. biomechanics, muscle imbalances etc).
After the initial 72 hours where RICE protocol has been followed, a rehabilitation programme for grade 1 or 2 strains may include;
1 week (approx..) after injury
Gentle stretches to affected muscle within a pain free range of motion
Light muscle activation exercises under supervision from a health professional such as hamstring curls against light force provided by the therapist. This should be pain free!!
Approx. 2 weeks after injury
3 weeks (approx.) after injury – all exercises should be pain free
4 weeks (approx.) after injury
Include backward running, and if pain free then progress to full pace forward running
Continue stretching and strengthening exercises
Slowly re-integrate into training and competition
Allow grade 2 strains more time to heal correctly compared to a grade 1, but every injury is different and will follow a different time line.
Management of complete ruptures of muscles should be based on advice followed by orthopaedic specialists and any relevant professionals.
‘Prehabilitation’ and prevention
Rehabilitation exercises should be continued after pain has subsided and the injury has recovered, to prevent future re-injury.
Prehabilitation should include;
Mobilisation of lumbar spine, hips, knees and ankles to improve/maintain a good range of motion through the lower extremity to improve force transference (advice can be provided by manual therapists)
Stretching exercises to improve flexibility
Conditioning to improve fitness and prevent fatigue contributing to muscle damage
Strengthening as performed during rehabilitation but eccentric such as Nordic hamstring lowers and Glute Ham Raises can be included
You should also make sure you have adequately warmed up and cooled down before and after exercise.
Prehabilitation is not just for those who have suffered an injury. Adding in exercises to improve mobility, flexibility, strength and conditioning of muscle groups and joints can help stop those who are injury free from becoming injured.
Please note the information in this article should in no way be used to replace seeking professional advice from a health professional. If you are unsure about your injury, or need help with recovering from an injury (from sport or otherwise) then it is always best to seek help.
1. Brukner, P., Khan, K., et al. (2012) Brukner & Khan’s Clinical Sports Medicine. 4th Ed. North Ryde, Australia: McGraw-Hill Education
2. Brukner, P., et al. Reccurent hamstring muscle injury: applying the limited evidence in the professional football setting with a seven-point programme. Br J Sports Med. 2013;0:1-12
3. Pollock, N., et al. British Athletics muscle injury classification: a new grading system. Br J Sports Med. 2014;48:1347-1351