The hamstring group is made up of three muscles on the posterior part of your thigh.
The bicep femoris, semitendinosis, and semimembranosis arise from the lower part of your pelvis (your sit bone), and span across the hip and knee joints before inserting into various locations around your knee and upper shin.
The function of the hamstrings is to extend the hip and flex the knee. The hamstrings play a vital role in sports that require sprinting. AFL, soccer, and track events are amongst the most common sports with a high prevalence of hamstring injuries.
There are several locations where the hamstring can be injured.
The rehab time and process may vary slightly depending on the location and tissue type.
The epimysium (the sheath around the muscle tissue)
The musculotendinous junction (the muscle tendon interface)
The muscle belly (muscle cells of fibres)
The intramuscular tendon (also known as the central tendon - central support along the length of the muscle where muscle fibres attach)
When a muscle belly is injured immediate bleeding will occur at the site of injury. Level of tissue damage and disruption depends on the severity of injury and the location of injury
Bleeding will then begin to clot and the natural inflammatory response of the body will kick in. In severe injuries, this is very obvious through visible bruising at the site of injury.
Note - It is important that we allow this process to occur naturally – anti-inflammatory medications and icing may inhibit this process, so speak to your physiotherapist about what is best for your condition.
The second and third phases of healing focus around repair and remodelling.
The body is able to clear out the damaged tissue and regeneration of healthier tissue occurs. At first, the new tissue is not particularly strong.
Exercise and loading are very important during this phase to stimulate better remodelling and orientation of the new muscle tissue.
How to best treat your hamstring strain
1. Deload and avoid running for 1-4 days
While you don’t want to over stretch your hamstring in this early phase, it is still important to gently take it to end of range.
Avoid anti-inflammatory medication for first 48 hours
Compression is extremely important in early days
2. Early Mobilisation
It’s a fine balance rest and loading (more on this later)
3. Return to steady state running and aerobic conditioning
Hamstrings can tolerate slow steady state running as early as day 3-4 post injury
Pain free walking and hamstring bridges should be cleared before commencing running
Cross training exercise like cycling can also be beneficial
4. Restore strength to your hamstring
Progress through appropriate stages of static, dynamic and eccentric (muscle lengthening) strengthening exercises
Performing appropriate reps and sets of nordic hamstring exercises you can reduce your injury risk by up to 50%
You will need to have 90% strength of asymptomatic side before return high speed running and perform at least 25 reps of single leg hamstring bridges
Athletes will need to clear several sprint sessions within a week before return to play
Sprinting should closely resemble match scenarios, e.g short near max efforts with recovery between
Sprint training should be maintained to reduce injury recurrence
** Remember that some of these phases will occur concurrently, e.g basic static strengthening exercises will commence very early in the process and continue while aerobic conditioning is increased.
Benefits of early mobilisation for hamstring strains
Gone are the days of totally resting injuries. We know that early appropriate mobilisation of soft tissue injuries leads to greater healing in the early stages. It also works to reduce short term wasting and loss of strength.
When we add load to a muscle (exercise it), we stimulate healing at the cellular level. Increased growth factor, better orientation of muscle fibers and reduction of scar tissue are just some of the benefits of early mobilisation.
Studies have compared muscle injuries that have been rested, and muscle injuries that have been mobilised over a 21-day period. What they found was that no regeneration occurred in the immobilisation group. Once the immobilisation group started their rehab after 21 days, it was a much slower return to strength compared with the group that started their rehab on day 2.
The takeaway message here is that just time alone will not return muscle strains to their previous level of strength and performance. If an individual is coming to physiotherapy after 2 weeks of ‘resting’ their hamstring injury, their time to recover really starts when their rehab starts.
Nordic Strengthening for hamstring stairs: Is it beneficial?
The Nordic exercise is a strengthening exercise that is performed while lengthening the hamstring under load. Most professional sports clubs will use a Nordbord to gain objective data about eccentric hamstring strength (strength while lengthening).
The average person however can pair up with a buddy, get them to secure their ankle, and perform an at home version that is just as effective.
The Nordic exercise has been studied a lot in the literature for it’s benefits around injury prevention. Low level reps and sets several times per week is all that is needed to significantly reduce your risk of injury recurrence.
Be warned, this is a very tough exercise. Small doses can result in delayed muscle soreness for several days. It is important you consider when you perform these exercises in your rehab week. Always be guided by your physio for timing, frequency and dosage of any exercise prescription.
Ways to prevent further hamstring strains injury.
Be consistent with your load and stay aerobically fit
Sprinting – remember to train > 90% of maximum pace
Strengthening – include exercises that work across all ranges hip extension and knee flexion