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18th January, 2017

malvernphysio

Hamstring Strain Injuries

Keith recently attended the Sporting Hamstring course conducted by Geelong Cats head physio Mark Young and AIS track and field physio Ben Raysmith and provides insight into how to prevent hamstring injuries.

Hamstring strain injuries (HSI) remain at the forefront of the sports medicine agenda, as they continue to be the most common injury in many sports including Australian Rules Football (AFL), soccer and athletics. The prevalence of hamstring injuries is quite concerning, with recurrence rates documented to be as high as 30%. Specifically within the AFL, the 2015 Injury report documented approximately 5 new hamstring injuries per club over the season, 19 missed games per club and a recurrence rate of 16%. These statistics promote the discussion of evidence-based practices that could help minimise or prevent these injuries from occurring.

From a medical perspective, prevention of injuries not only reduces medical expenditure but also the mental burden of injury for the athlete.

From a coaching and club perspective, fewer injuries allow coaches a larger selection of available players, resulting in a stronger and more competitive team. Recent literature supports this theory: lower injury rates = greater team success.

So why are hamstring injuries so prevalent in these types of sports? Recent research conducted on an AFL population identified that 80-85% of all hamstring injuries occurred during high speed running. During high speed running there is a rapid change in muscle length (from a lengthened position to a shortened one) resulting in maximal load and strain placed on the muscle complex. Below are two examples of hamstring injuries occurring in a sporting environment.

The hamstring consists of 3 muscles; Biceps Femoris, Semitendinosus and Semimembranosus. The Biceps Femoris can be attributed to 80-85% of all hamstring injuries. From this statistic, it can be easy to target a strengthening program just for this muscle, however a greater understanding of the mechanics of the hamstring complex is integral to providing a thorough program.

It has been suggested that Semitendinosus (medial hamstring) is designed for larger movement output during gait, while Biceps Femoris (lateral hamstring) is designed for greater force production (stability) and very little movement. As semitendinosus fatigues, the running load and demands are placed on Biceps Femoris, leaving the latter muscle ‘out to dry’ and at risk of injury.

So how do we prepare our athletes to minimize their risk of hamstring injuries?

No previous hamstring injury:

For those with no history of hamstring injuries it’s pretty simple – get stronger! Target the hamstring complex both at the hip joint and knee joint. Recent data suggests that the Nordic lower and 45o hip extension exercises are the most specific at targeting both the medial and lateral hamstrings respectively.

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Variations of the bridge (double leg/single leg) should be undertaken to help develop muscle endurance. Hamstring strengthening exercises must also incorporate muscle movement specificity, meaning that you must train the muscle in the way you plan to use it. For example, certain sports that involve changes in speed require a rapid change of contraction in the hamstring. For those sports, that particular movement pattern needs to be addressed and trained.

Previous history of hamstring injuries:

Although the mantra of ‘get stronger’ also applies to this subgroup, hamstring injuries have been shown to have multiple contributing factors. Not only does the injury highlight a weakness in muscle strength, but often contributions from the lumbar spine, neural (nerve) structures, poor pelvic control and running technique can also lead to injury reoccurrence. Cyril Rioli is a case-in-point; there were several contributors that led to his HSI reoccurrence.

Identifying and addressing the various contributing factors is essential to give the athlete every opportunity to minimise their risk of injury, enable them to continue playing the sport they love, and give their team every opportunity for success throughout the season.

Book an appointment with Keith today to strengthen your Hamstrings or have an existing injury assed by sending us an email or calling us on 9078 8434.