Most hamstring-injury management is based on ‘old-school’ sports trainer techniques and not on evidence-based practice. Furthermore, the different requirements of certain sports will determine the rehabilitation of these injuries. Sprinters, for example, who need top-end speed in a straight line will have different functional needs to a soccer player who must constantly change directions at sub-maximal speeds.
All sport medicine textbooks have a chapter on the immediate management of muscle injuries. The most important procedure in the management of soft-tissue injuries in sports people is initial icing while moving the muscle, known as ‘cryokinetics’. This is done by sitting with an ice bag under the hamstring and keeping the hamstring moving by bending and straightening the knee to the point of mild discomfort. This satisfies the immediate goal of reducing swelling and subsequent haematoma, and the addition of movement results in less ‘ice scarring’. Ice scarring is a phenomenon whereby the superficial fascia adheres to the underlying muscle and affects the overall gliding of the muscle in relation to its covering fascia. The end result is a muscle that moves with its adherent fascia whilst contracting. The quickest way to cause ice scarring is to over-apply ice to the injured area and to keep the muscle completely still while being iced. One must be certain before applying ice to a hamstring injury that a local muscle injury does exist. Icing a ‘neural hamstring’ with no local muscle pathology will result in more reflex muscle tone and more ice scarring.
The use of non-steroidal anti-inflammatories (NSAIDs) has been a controversial issue in sports medicine since the mid 1990s when research showed that NSAIDs slow down the healing rate of muscle injuries. One must be careful with the overzealous use of NSAIDs in muscle injuries, especially the COX-1 inhibitors (e.g., Diclofenac, Ibuprofen). It has been suggested that the new range of COX-2 inhibitors (e.g.: Celebrex, Vioxx) have minimal delayed healing effects and are thus safer to use for an anti-inflammatory and analgesic effect.
Any therapy that reduces muscle tone in the hamstring (both ‘neural’ and ‘muscle’ pathologies) will be a useful adjunct in the treatment of this injury. This may be any soft-tissue massage or ‘trigger point’ injection therapy.
A critical element is the rehabilitation of true muscle injuries. As stretch and contraction become pain-free, direct loading to the hamstring is necessary to increase the tensile properties of the healing tissue, as well as developing fatigue tolerance in the newly developed scar tissue and hamstring muscle tissue.
The commencement of direct rehabilitation should begin when range of motion and strength testing become pain free. The number of repetitions, sets and selection of exercises will be determined by the response of the muscle to stretch and contraction. If, for example, straight-knee bridging is pain-free but bent-knee bridging is not, then straight-knee bridges can be incorporated into the programme while bent-knee bridges can be incorporated at a later date.
A typical routine for hamstring rehabilitation may be as follows: Start with gentle cycling for 10 minutes followed by five minutes of straight-knee and bowstring stretches. The order for the hamstring exercises and relevant progressions are:
A word of caution when using rehabilitation exercises with ‘neural hamstrings’. If the hamstring problem is due to an increase in tone, then repetitive contraction of the muscle may actually increase tone and make the hamstring feel worse (read tighter). Clinical judgement in differentiating between true muscle injuries and neural problems is essential here. Clinicians cannot simply assume that all hamstring problems involve pathology and must therefore be ‘rehabilitated’.
The following rehab running protocol applies to both muscle tears and neural hamstrings. The muscle pathologies will take longer to progress through the stages.
As soon as an injured athlete is able to walk pain-free, then running may commence. However, this running protocol must be controlled and follow a very set programme. Athletes will understand, when it is explained to them, that running by themselves with very specific criteria takes away risk factors that are potentially damaging to the muscle. For example, turning to chase an opposition player/team mate or reaching down low to catch a ball. They are less likely to re-injure in a controlled environment. Following this principle, an athlete may start sport- specific hamstring rehabilitation with the following rehab running protocol.
On a level running surface (track or grass) break up a 90-metre distance into three 30-metre zones. The first zone represents acceleration, the middle zone is holding pace, and the last zone is deceleration. The athlete can run to whatever speed he or she wish, as long as they feel no pain or restriction in the hamstring. If they feel the hamstring even with jogging, then they are not ready to start rehab running. This subjective element is the most important component of this exercise. Therefore a level of trust and understanding needs to exist between the athlete and therapist.
A warm up is not necessary as the initial run-throughs will act as a warm up. The athlete starts with a run-through over 90 metres as described above, and then walks back before going again. The speed can be progressed as long as the above subjective component of no pain/restriction is maintained. After four run-throughs, a five-minute rest period is allowed before the second set of four run-throughs. The total number of run-throughs will depend on the sport and the level of competition. For example, an élite-level Australian Rules Footballer or Premier League Soccer player will easily handle five sets of four (20 run-throughs). Élite- level Rugby Union backs will do well with four sets of four (16 run- throughs) and tight five Rugby players may only manage three sets of four (12 run-throughs). Again, this point cannot be over- emphasised; no pain or restriction is to be felt during the running. If the athlete runs with pain/restriction then the hamstring will react and tighten up. If no pain/restriction is felt, generally each repetition will gradually get faster as the hamstring relaxes.
The eventual goal is to get through all the run-throughs with at least the last two sets of four done at full pace. This may take two to three days or up to a week to achieve. When this is achieved, then the acceleration and deceleration distance is reduced to 20 metres, with a 30-metre maintenance zone, eventually aiming for full pace. When this is achieved, then decrease the acceleration and deceleration distance to 10 metres.
This process gradually tests the hamstring over a number of key aspects. First, can the hamstring handle contractile load (as it does at full pace running)? Second, can the hamstring handle contractile load under fatigue (as it will with 12, 16 or 20 run-throughs). Finally, can the hamstring handle rapid contractile load (as it does with rapid acceleration and deceleration)?
The last stage of the rehabilitation is to gradually add in game specific elements such as bending and picking up a ball at speed, kicking (especially long kicking), stepping at speed and finally contact and tackling. When these can be done with no pain or restriction, then the athlete is allowed back to full training.
The most valuable thing with hamstring running is that it can be done every day. This contrasts with other lower-limb muscles that cannot be trained every day and which will be covered in future articles in this series.
The usual timing of rehab running among other aspects is as follows: Physiotherapy or massage to the hamstring in the morning, followed by strength and stretch (if required); Rehab running early afternoon, followed by quick re-assessment of range of motion and strength testing and then quick flushing massage and then ice. Follow this up with another strength and stretch session late afternoon or early evening.
Finally, it is important to remember the statistics mentioned in the first part of this article in the last SIB. Within the first four weeks after return to sport, 25% of injuries will recur. It is therefore necessary to continue physiotherapy, massage and strength and stretch for a period of time after the athlete has returned to competition. Daily monitoring of range of motion and strength will highlight any potential problems that may recur. A skilled therapist will often be able to pick up changes in the hamstring muscle even before the athlete feels any functional limitation with playing and training.