Hamstring

Functional anatomy

• Biceps femoris has x2 heads (long innervated by the tibial portion of sciatic nerve L5, S1-3) and short head innervated by the common peroneal portion L5, S1-2)

• The long head of biceps femoris and ST share a common proximal tendon that arises from the medial facet of the ischial tuberosity

  • ST fibres originate from the ischial tuberosity and the medial aspect of the common tendon and inserts into the pes ansering; whereas the biceps femoris long head originates from the lateral aspect of the common tendon ~6cm below the ischial tuberosity and attaches into the common distal tendon of the short and long head and attaches into the lateral femoral condyle, fibula head, popliteus tendon and the arcruate popliteal ligament.

  • The short head of the biceps femoris originates from the linea aspera

  • The SM has it’s attachment at the lateral border of the ischial tuberosity, and it’s tendon is >10cm long that eventually crosses over anteriorly to the BF and ST muscles.

 

 

Clinical approach

• Must have correct diagnosis à don’t misdiagnose hamstring strain with lumbar spine referred pain. A hamstring strain is usually due to a substantial force; a particular point in time. It may be related to an eccentric contraction or an excessive stretch; whereas without a strong history of injury, consider referred pain

 

History

1. Level of activity

   1. Has a change in training coincided with injury?

   2. Is there an adequate base of training?

2. Occupation/lifestyle

   1. What factors outside of sport could be aggravating the condition?

3. Incident

Yes: consider a strain, fascial/neural trauma

If there is an incidence, what was the MOI? What was the intensity of the pain at initial injury? (A higher VAS score >6/10 is shown to be significantly associated with a RTP of >40 days)

No: Consider overuse, referred pain, alternative abnormality

1. Immediate impact on function

2. Being forced to stop participating in sport within 5minutes of the initial incident is associated with an increased time to RTP

3. Progress following injury

   1. Slow: indicates a more severe injury

   2. Erratic: Strain is being aggravated by activity or injury is not a strain

4. An inability to walk pain free within one day following injury shows a 4x more likely chance to require >3 weeks for RTP compared to those that could walk pain free within one day

5. Aggravating factors

   1. Incident related: useful for specificity of rehab

   2. Non-incident related: eradication or modification for recovery and prevention i.e. hamstring pain with sitting requires ergonomic modification)

6. Behaviour with sport

   1. Warms up with activity, worse after = inflammatory pathology

   2. Starts with minimal or no pain, builds up with activity but not as severe after: claudicant, either neurological or vascular

   3. Sudden onset: mechanical (i.e. strain)

7. Night pain

   1. Sinister pathology

   2. Inflammatory condition

8. Site of pain

   1. Posterior thigh and/or lower back = lumbar referral or neuromotor/biomechanical mediator

   2. Buttock, SIJ w/o lumbar symptoms = gluteal trigger points

   3. Ischial = tendinopathy/bursitis/apophysitis/avulsion

9. Presence of neurological symptoms

   1. Nerve involvement

10. Recurrent problem

    1. Extensive examination and rehabilitation required

    2. History of hamstring injury in the previous season = strong predictor of recurrence

 

Acute hamstring strain

• Sudden onset​

• Moderate to severe pain

• Disabling – difficulty walking, unable to run

• Markedly reduced stretch

• Markedly reduced contraction with pain against resistance

• Local hematoma, bruising

• Marked focal tenderness

• Slump test -ve

• +/- gluteal trigger points

• May have abnormal lumbar spine/SIJ signs

Referred pain to posterior thigh

• May be a sudden or gradual onset or feeling of tightness

• Usually less severe, may be cramping or “twinge”

• Often able to walk/jog pain free

• Minimal reduction in stretch

• Full or near full muscular strength against resistance

• No local signs

• Variable tenderness, usually non-specific

• Slump test frequently +ve

• Gluteal trigger points that reproduce hamstring pain on palpation or needling

• Frequently have abnormal lumbar spine/SIJ signs

 

Acute hamstring muscle strains

Majority of strains are to the biceps femoris (83%), SM (12%) and ST (5%).

There are 2 distinct types, distinguished by the injury situation and can give an indication of prognosis; differentiation of the types can also be done by maximal palpation pain and MRI during the first 2 weeks.

• Type 1; occurs during high speed running and the athlete complains of a sudden onset of pain that stops them

  • Typically, they cause a more acute decline in function, but a shorted RTP than type 2

  • Usually involve the BF at the proximal MTJ.

• Type 2; occurs during extensive lengthening in hip flexion combined with knee extension (high kicking, sliding tackle and forward splits (ballet dancing or gymnastics))

  • Usually located close to the ischial tuberosity and involve the proximal free tendon of SM

  • Have a longer RTP than type 1

  • Passive stretching, and heavy load exercises seem to aggravate these types

 

Prognosis of hamstring injuries

The following factors have been shown to associated with an increased length of time to RTP

1. Time (days) to walk normal pace pain-free (>1 day = 4x more likely to take >3 weeks)

2. Days to jog pain-free

   1. 1-2days <2weeks RTP

   2. 3-5days >2weeks RTP

   3. >5days >4weeks RTP

3. MRI -ve ‘hamstring strains’ are associated with relatively rapid time to RTP and are relatively common

4. The more proximal the injury, the more prolonged the RTP (however this is in contention)

5. Injury to the intramuscular (‘conjoint’ or ‘central’) tendon of BFLH is associated with a long RTP (3-4months)

6. A ‘kicking’ or ‘slow-stretching’ MOI is associated with a longer rehabilitation period than a high speed running mechanism

7. Forced to stop training/playing within 5minutes following onset of pain

8. Greater maximum pain intensity at time of injury

9. Longer length of hamstring tenderness in cm

10. PROM deficit recorded within a few days of injury occurrence using the passive SLR or the active knee extension test

11. Longer craniocaudal length of lesion on MRI

 

 

Hamstring injury management

Phase

Key criteria

1. Acute management phase

 

1. Begin running/active rehabilitation (i.e. begin subacute phase)

• Pain-free walking

• Adequate force with resisted muscle contraction

1. Return to full training

• Complete resolution of any symptoms with maximal resisted muscle contraction

• Equivalent tenderness on palpation (R=L)

• Full and symptom free ROM/flexibility (R=L)

• Successful completion of a structured running program (i.e. maximal sprinting speed achieved at the end of the running program is comparable to the athletes previously recorded benchmark when uninjured

• Successful completion of appropriate rehabilitation exercises

• Successful completion of controlled functional (sports-specific) tasks simulating the original MOI

1. Return to play

• Successful completion of at least one full week of normal training load with no adverse reaction in any clinical and/or functional sign and symptoms

• Additional quantitative tests of hamstring function (HHD, isokinetic dynamometry, Asklin H-test, single leg bridge capacity testm performance on Nordic hamstring exercise); compare data for injured limb to uninjured limb or to data collected prior to injury

• No adverse psychological characteristics, such as apprehension regarding RTP or fear of re-injury

 

Acute management phase: the aim is to facilitate myofibre regeneration and minimse fibrosis.

• RICE for 10-15minutes every 3-4hours for the first few days until symptoms settle

• Muscle activation: muscle contraction promotes;

  • angiogenesis which increases the likelihood of delivering muscle-derived stem cells to the injured region and,

  • aims to prevent neuromuscular inhibition around the injured area

  • The introduction of frequent, low-grade, pain-free muscle contraction immediately following injury can be advantageous

 

Criteria for progression to subacute phase

• Once the athlete is pain-free with walking and adequate/sufficient force can be generated without pain on resisted hamstring contraction, then jogging can commence and gradually increased

• Usually within 4-6 days there is considerable improvement in signs and symptoms however this doesn’t indicate a hamstring that is ready for high loads

 

Subacute/conditioning phase

Stretching: a controlled stretching regime MAY be employed. It may be more important to focus on other areas i.e. hip flexors,

Manual therapy: neural mobility is frequently a problem with hamstring strains, therefore neural mobilising exercises should be employed.

Strengthening: Need to consider the type of contraction, the length of the muscle-tendon unit and the speed of contraction AND the differentiation between medial and lateral hamstring.

• Exercises should be used that have an emphasis on eccentric contractions and extensive lengthening. Exercises should also focus on muscles that load the hip and the knee simultaneously

• The L-Protocol (lengthening protocol) consists of 3 exercises aimed at loading the hamstrings during extensive lengthening and can begin 3-5 days after injury but not pain should be provoked

1. The extender (aimed at increasing flexibility)

2. The diver (aimed at hamstring strength and trunk/pelvis stabilisation

3. The glider (specific eccentric hamstring exercise)

Other example exercises include;

• Standing single leg hamstring with theraband

• Single leg bridge on chair

• Single leg ball roll outs

• Single leg slide outs

• Single leg reverse deadlift with kettle bell

• Yo-yo

• Nordic drops

  • Must be completed every other day for DOMS and compliance

 

Week

Sessions per week

Sets and reps

Load

1

1

2x5

Load is increased as subject can withstand the forward fall longer. When managing to withstand the whole ROM for 12 repetitions, increase load by adding speed to the starting phase of the motion. The partner can also increase loading further by pushing at the back of the shoulders

2

2

2x6

3

3

6-8

4

3

3x8-10

5-10

 

3x12/10/8

A 5-10 week pre-season nordic program.

 

Strengthening for hamstring synergists: must also target the hip extensors (i.e. GMax helps to restrain the trunk from flexion of the stance leg, decelerate the swing leg and extend the hip (it’s moment arm is best when the hip is in extension, whereas the moment arm of the AddMag is when the hip is in flexion)

 

Neuromuscular control exercises: an ability to control the lumbopelvic region (i.e. APT/PPT may be needed for sprinting etc.). Motor control of the lumbar spine stabilisers should also be considered.

 

Functional progression: Early commencement of a structured running program is an important part of rehabilitation.

 

Key principles to consider when designing a running program following hamstring muscle strains

 

1. Initially, running sessions may be completed 5-6x per week in the initial stages when volume and intensity are low. However, when the sessions become more advanced, a day on/day off approach is recommended which allows time to recover and adapt between sessions. It also allows the clinician to monitor the response to the load and to plan the following session accordingly.

2. Running can commence once the athlete is capable of producing force with resisted muscle contraction and has no pain with walking or other everyday activities. Begin with slow jogging intervals, and then progress fartlek-type running as tolerated (e.g. 15-20 repetitions of a 10second walk followed by a 20second jog followed by a 30second run).

3. Once the athlete is capable of achieving ~50% pace without symptoms or apprehension, then running may be progressed to a structured running program that involves repeated strides over a distance of 60-90metres at a prescribed intensity. In order to increase the dose of high-speed running in the latter stages of the rehabilitation process, extra interval running at a safe intensity can be completed in addition to the structured running program (e.g. 150m or 200m repetitions)

4. Load on the hamstrings increases with faster running. Therefore, running speed both within a session and from one session to the next should always be progressed in a graduated manner. Rapid increments in running intensity should be avoided, especially during the early stages of the rehabilitation process.

5. The warm-up prior to running should consist of jogging as well as footwork and agility drills

6. Sprinting technique drills should also be integrated into the running program (e.g. as part of the warm-up). Sprinting technique drills have been shown to be effective in improving an athletes lower-limb joint position sense.

7. Sport-specific training drills should be included in the final stages of the rehabilitation process and should simulate the original MOI as closely as possible.

 

Return to play phase

A “pain-free movements” criterion IS NOT ENOUGH. A criteria based approach that includes objective and quantitative tests has the potential to identify deficits and address them in a systematic manner during the stages of returning to sport;

• No difference in tenderness with palpation for injured vs uninjured hamstring

• Full ROM measured via:

  • Active/passive SLR test

  • Active knee extension test

• Pain free maximal isometric contraction

• Objective strength assessments measured via:

  • Hand-held dynamometer or isokinetic dynamometer

  • Performance with the Nordic hamstring exercises

  • Performance with the single-leg bridge capacity tests

• Askling’s H-test

• Completion of structured running program:

  • Maximal sprinting speed achieved at the end of the running program is comparable to the athletes previously recorded benchmark when uninjured

• Functional tests:

  • Repeat maximal accelerations from a standing start over a variety of distances (e.g. 5m, 10m, 15m, 20m)

  • High intensity weaving/cutting and random (unanticipated) agility exercises

  • Successful execution of sport-soecific activities

• Successful completely of a sufficient amount of standard training sessions

• Evaluation of an athletes psychological status regarding readiness for RTP and fear of re-injury.

 

 

Objective assessment

Screen lumbar spine/pelvis

 

ASLR +/- neural bias:

Grade 1 – will typically have full ROM with slight symptoms. Leg may feel ‘heavier’

Grade 2 – 60-90degrees

Grade 3 – small ROM

 

To remove the neural component of the SLR, bring hip to 90deg and then assess knee extension

 

Provocation test:
DL bridge – look for pelvic drop, pain, ease of completing and reluctance

• Grade 1 can usually bridge

• Grade 2 may have difficulty

SL bridge off of floor – look for pelvic drop, pain, ease of completing and reluctance

SL bridge off of therapists shoulder

Drop test - SL bridge off of therapists shoulder but “catch” the pelvis before it hits the bed. This is a quick movement

These help to determine if the patient is able to load the area

 

Slump test: gives more information if not a straight forward muscle strain. Also if there is chronicity or trouble differentiating

 

Palpation: If it is determined it is a muscle injury, not referred pain. Helps to determine injury site. Palpating with knuckles can help to feel fascially.

 

Strength testing: 90deg, 45deg, 0deg of flexion – looking for pain, cramping or areas of discomfort

 

Imaging: MRI or diagnostic US if there’s something that will change your management. May not need it for anything <grade 2. Ensure to exclude an avulsion injury at the ischial tuberosity (classical water skier).

 

Screening:

• Sit and reach

• Ankle DFx

• Screening of Lx spine and SIJ, ankle DFx ROM

• Neural tension (scarring/tethering of sciatic nerve)

 

Pathophysiology:

• In the first 3-8days – acute inflammatory/reaction phase

• The use of NSAIDs is not recommended and may slow healing process

• Hamstrings type 2>Type 1 fibres

• Biggest risk is previous hamstring injury

 

 

 

Management

Grade 1 / Grade 2: use the ‘no pain as a guide’ – happy with activation, not pain.

• Isometrics are used early to continue neural connection etc without stirring everything up

  • Sitting on plinth isometrics 5-10 second holds

  • Gradually progress the degree of knee flexion as tolerated

  • Squeezing adductor ball bridge ensuring pelvic neutral, core etc with a 3-8second hold 10x3

  • Long lever single leg bridge

• Monitor symptoms during, after and following morning to appropriately gauge next dosage

• Ensure 2-3/10 VAS maximum day to day and with activities

• Introduce loading in logical way – isometric à isotonic. We want to rehab a HSI in all ranges of knee angle and hip angle

• Ensure fatigue resistance

 

 

Once you’ve established a good strength baseline on the bed, progressing them is important and use pain as a guideline. We want them to experience DOMS afterwards.

• 3x per week

• Training sessions 2 on / 1 off

• Walking pain free à stairs à early introduction of running (pain free) lateral/forwards and agility activities

  • Example running program:

1. Running straight line

2. gentle S-curve,

3. criss-cross

4. & 5. Short sharp sprint/deceleration/stop dead/picking balls up off ground/COD

 

 

Return to sport:

• Ensure synergists (quads, calves etc)

• Time out is proportional to severity of injury ~3weeks for a grade 1

• Maintenance continues!