Hamstring strain

By Juniors Editor on

With the finals just around the corner, we thought we would take the opportunity to talk about an injury that commonly rears it’s ugly head towards the back end of the season. Hamstring injuries are highly debilitating and account for the majority of injuries, between 6% and 29%, across football, AFL, rugby union, basketball, cricket and sprinters (Ahmad et al., 2013; Goode, A. et al, 2015). The main concern is that they continue to present long-term ailments for athletes following full recovery, with a recurrence rate of 12–31% (Ahmad et al., 2013; Kerkhoffs et al., 2013). Specifically in football, hamstring strains account for 90 days off training and 15 missed matches per season, per team.

Today we will identify some key aspects of assessment, treatment and prevention in order to help you reach your peak at the business end of the season!

Anatomy: What is a hamstring strain?

A hamstring strain can occur in any of the four muscles which comprise the hamstring. You have the semimembranosus, semitendinosus and the biceps femoris - short and long heads, the latter being the largest and most common to be injured. The severity of strain can range from mild to severe, and is dependant on the amount and location of tissue damage.

They usually occur in two particular instances; slow velocity stretching-type activities (e.g. dancing, gymnastics) or high velocity contraction-type activities (e.g. sprinting, jumping). With football, the majority of hamstring injuries occur during sprinting, in the late stage of the swing phase due to poor intermuscular coordination and reduced eccentric strength of the hamstring muscles at large knee extension angles (Chumanov, Heiderscheit & Thelen, 2011). A positive is that these ‘sprinting’ type tears take significantly less time to rehabilitate.

Causes: What happens to cause the strain?

The majority of hamstring injuries occur in the final 10-15 minutes of the first and second halves (approx. 50%), suggesting fatigue and muscle overload are key issues leading to injury. Hamstrings primarily consist of fast twitch muscle fibres that fatigue quickly and as a result they are unable to absorb the same amount of force and load effectively. As a result, when you continue to train and play at high intensities, your risk of strain increases as the hamstring continues to contract and lengthen at the same higher loads. It’s advised that you should monitor your own fatigue levels during training sessions, and it’s suggested that all high intensity training is conducted earlier in the session to avoid muscle overload. This risk is also minimised via proper dynamic warm-ups, consisting of active and dynamic stretches and exercises to prepare the hamstring muscles for the forces involved.

With all the focus being on fatigue and muscle overload, as one of our previous articles highlighted, recovery is an integral element of your training regime. Reduced strength and tightness following intense trainings or games can be mediated with proper stretching, foam rolling, sports massage or therapeutic exercises prescribed by your physiotherapist.

Preceding factors that can also cause hamstring strains are:

  • Low eccentric strength is an emerging strong predictor to identify those at risk of hamstring strains. During sprinting, as you extend your knee during the late swing phase, if your hamstring is weak during this eccentric contraction, it can result in a tear. It is a simple measure which can be tested in clinic via many means by your physiotherapist. If it can be identified it can also be changed – PhysioWorks has developed an 8-week program in order to help rectify weakness in this area.
  • Poor running mechanics: this consists primarily of overstriding or poor pelvic control, which puts the hamstrings in a vulnerable position throughout swing phase and initial ground contact.
  • Lower back or sacro-iliac dysfunction: Abnormalities of the dynamic control of the lumbar spine and pelvis can cause biomechanical changes and nerve dysfunction with the subsequent muscle weakness which predisposes you to injury.

Symptoms and diagnosis: How do I find out what happened?

Hamstring strains are commonly diagnosed via physical examination, but sometimes require an MRI. The MRI may be used to identify the grade (1-3) of tear and its exact location. This is helpful in judging the length of your rehabilitation and possible return to sport time-frame. Clinically, your physiotherapist or sports physician will look for signs of pain on hamstring contraction, reduced hamstring flexibility, tenderness or a palpable lump or gap within the hamstring muscle bulk.

A Grade 1 hamstring strain is usually categorised by a loss of strength (difficulty bending your knee against resistance and running) but not length. They usually cause some tightness/spasm, swelling and discomfort in the back of the thigh but your ability to walk should not be hindered.

1–3 weeks rehabilitation

A Grade 2 hamstring strain is usually categorised by a loss of strength (difficulty bending your knee against resistance, walking & running) AND loss of length. Sudden twinges of hamstring pain during activity will be present and limping may be necessary to ambulate. There will be tenderness, swelling and bleeding/bruising within 24 hours.

4–8 weeks rehabilitation

A Grade 3 hamstring strain is a severe injury involving a tear to half or all of the hamstring muscle and is very rare. You will require crutches to walk and will feel severe pain and weakness in the muscle. Swelling will be noticeable immediately and bruising will appear within 24 hours.

3–6 months rehabilitation and potential surgery

Treatment: How do I get back on the pitch?

Physiotherapists’ role

Many patients with a hamstring strain start to feel better within a few days of the injury, however whether it’s quite severe or only a slight ‘niggle’ it’s incredibly important to have it assessed and get appropriate professional guidance following an accurate diagnosis.

The physiotherapist will aim to:

  • Reduce hamstring pain and local inflammation.
  • Normalise your muscle range of motion and extensibility.
  • Strengthen your knee muscles and hamstrings, paying particular focus to eccentric strength.
  • Strengthen your lower limb muscles: calves, hip and pelvis muscles.
  • Normalise lumbo-pelvic control and stability (a co-factor in many hamstring strains).
  • Normalise your neurodynamics to enable your sciatic nerve to pass freely without scar adhesions.
  • Improve your game speed, proprioception, agility and balance.
  • Improve your technique and function (eg. running, sprinting, jumping, hopping and landing).
  • Minimise your chance of hamstring re-injury.

Your role

As previously noted, there are extremely high hamstring re-injury rates due to a poor rehabilitation process, lingering strength deficits or early return to sport. To reduce the likelihood of recurrence, it starts with completing your rehabilitation and ‘home- or gym-based exercise programs’ to normalise any strength or length deficits still evident post-injury.

What next? Am I at risk of a hamstring strain?

There is a continuing improvement in research surrounding risk factors and prevention of hamstring injuries, which has led to a number of clinical measures that physiotherapists can assess and monitor to potentially lower your risk of injury.

These measures include such things as:

  • Eccentric hamstring strength (the ability to contract the muscle and lengthen it at the same time).
  • Isometric hamstring strength at lengthened positions.
  • Function-specific and lower kinematic chain testing.
  • Deep core and pelvic control.

These assessments are particularly important for those who have had a previous hamstring injury. If you have had a previous injury, or you would just like a thorough assessment to potentially reduce your risk of injury, join us in the clinic and we can provide you with guidance and a personalised strengthening and control program to assist your athletic endeavours.

If we can measure it and identify deficits, we have a better chance of preventing them!

Please contact your physiotherapist for more advice regarding hamstring injuries:

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