Hamstring Strains – Is Stretching the Answer?

Introduction

Muscle strains are common in masters runners, triathletes and team players. In running activities, this injury often occurs at the end of the swing phase, as the leg is rapidly extending before being planted on the ground. This injury can often take some time to heal and there is a high risk of re-injury. In fact, one study on elite football players reported a 30% reinjury rate.

Most of we older (and hopefully wiser!) athletes include stretching as part of our regular exercise routine as a way to prevent injuries, muscle soreness and improve our sporting performance. However, with the time pressures of work and family and our enthusiasm to just get out there and train, sometimes we omit it all together. All too commonly, we only commence stretching after an injury, when our physiotherapist or chiropractor tells us to.

The question often asked these days is: Is hamstring stretching of any benefit in preventing hamstring injuries?

Where is the evidence?

 A recent article in the Strength and Conditioning Journal sheds some light on this question. The authors describe the scope of hamstring strains, the risks of recurrence and strategies to minimise recurrence risks. Data from the US collegiate sports system reports hamstring strains to be the second most commonly reported injury. Whilst factors such as age and injury history both affect injury risk, this report provides evidence that hamstring flexibility is NOT a predictor of hamstring strain. In fact there appears to be evidence that quadriceps flexibility and quads/hamstring muscle strength imbalance are more reliable predictors of hamstring strain. More specifically, eccentric hamstring strength (the ability of a muscle to produce force whilst lengthening) is altered as a result of previous injury. It seems that the repair process of an initial injury results in scar tissue. This new tissue is relatively inelastic and non-contractile. This changes the stiffness of the muscle and its ability to produce force near terminal extension; the range of motion where recurrent hamstring strains occur. Stretching does not restore this loss of strength, however eccentric exercise may.

So What?

 There are 3 strategies you can implement to reduce the risk of hamstring strain recurrence:

  1. Dynamic warm up – this should include range of motion, running drills and low level plyometrics (skipping, hopping, jumping). Change of direction skills should be used if appropriate
  2. Core or trunk stabilisation exercises – depending on the sport, these may include Swiss ball exercises, planks or exercises in single leg stance
  3. Eccentric strength training – typically this may include Nordic hamstring exercises however low intensity single leg landing exercises, eccentric step downs, lunges, Zerchers or Waiter bow exercises may be better alternatives

Programs incorporating the above elements have been shown to significantly reduce hamstring strain recurrence. Despite this evidence, there appears to be no reason not to stretch. Almost all athletes say they feel better when they stretch and it is unlikely to reduce performance, even in sprint or power efforts.

Source: Sherry, M et al; (2011). Hamstring Strains: Basic Science and Clinical Research Applications for Preventing the Recurrent Injury. Strength and Conditioning Journal, 33(3): 56-71

Masters Athlete thanks Rob Stanton, an Accreditted Exercise Physiologist and Level 2 Strength and Conditioning Coach for contributing this article. Rob is co-founder and Director of Vector Health and has over 15 years experience in the assessment and prescription of exercise for athletes, rehabilitation and in the management of chronic disease. He is a former coach of Australian Powerlifting teams, Queensland Academy of Sport regional Strength and Conditioning supervisor and has worked with athletes from grass roots to Olympic level. Rob can be contacted by email at rob@vectorhealth.com.au

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