5EpidemiologyFA Audit of Injuries study found that 12% of all injuries reported over two seasons were hamstring strains. (Woods Br J Sports Med 2004;38;36-41)11-15% Cricket (Stretch 2003, Orchard et al 2002a)16% AFL with a recurrence rate of 34% Seward et al (1993)Incidence 0.30 per 1000 playing hours with average severity of 17 days absent in English Rugby Union – Brooks et al (2005)
6EpidemiologyEpidemiological evidence suggests that hamstring strains are associated with eccentric load, where the contracting muscle is lengthened and there may well be a lack of neuromuscular control.Biggest risk of injury is previous injuryBiceps femoris most commonly injuredIncreased incidence with age
10DiagnosisListen Hx is keyLookMoveFeelSpecial tests
11Neural DynamicsSlump test as a diagnostic tool Slump as a treatment modality Significant effect on Fascia – Vleeming et al 2005The slump test is said to significantly differentiate referred posterior thigh pain from that due to muscular-tendon strain  and has been able to identify those with recurrent hamstring strains in a small study . Slump stretching as a treatment procedure (when slump testing is positive) has been shown to be more beneficial in returning athletes to competition than standard physiotherapy treatment alone (ultrasound, massage, progressive flexibility and strengthening) . The slump test has been proposed to be a measure of 'neural tension' which is postulated to predispose hamstring injury . However, the anatomical relationship of the hamstrings with the thoracolumbar fascia (TLF) system has been neglected. The tendon of bicep femoris is continuous with the sacrotuberous ligament, passing across the sacrum and attaching to the thoracolumbar TLF . This functionally connects the hamstrings to the lumbar spine, upper torso, shoulder and occiput and casts doubt on reliability of the slump test as being able to measure neural tension . Contracture of the muscular attachments of the TLF has been documented to cause TLF its displacement . Therefore neural tension may only be an assumption and it may more likely be myo-fascial tension, or possibly a combination of the two giving a positive slump test. Postural changes such as forward weight bearing, as occurs during forward lean gait, will also cause hamstring tension and predispose hamstring injury. This suggests that the TLF system should be assessed during treatment of hamstring injuries.
12Lumbar SpineAge / Degeneration of L4/5 and L5/S1 associated with prevalence of hamstring injuries Successful management of hamstring injuries in Australian Rules footballers: two case reports Chiropractic & Osteopathy 2005, 13:4 doi: /Australian Rules footballers with a previous back injury have been found to have a significant increased risk of hamstring injury . A strong relationship between age and hamstring, calf and Achilles injuries (with a L5 and S1 nerve supply) also exists in AFL players . The L4/5 and L5/S1 levels are the most common areas for spinal degeneration and athletes are susceptible to degenerative changes at an earlier age than the normal population . Altered neural input from the levels that innervate hamstrings may be causing and prolonging hamstring injuries. Long term prospective studies are required to further investigate this finding.
13If your think the lesion is soft tissue Dynamic Ultrasound or MRI are you investigations of choice
14Common mechanism Late swing phase in running action Eccentric contraction to decelerate the shankOften accentuated in preparation to jump, kickTrunk flexion whilst running (Verral, 2005)
15Other mechanismsStretch with knee fully extended (stretching for a ball, kicking)Forced trunk flexion with foot planted (waterskiing)
17Intrinsic and extrinsic factors Musculoskeletal imbalancesAny breakdown in the effective function of the legs and pelvis during running may predispose to injury. Examples include:postural changes due to muscle tightnesslumbar or sacro-iliac joint stiffnesspoor co-ordination of movement or early fatigue associated with muscle weaknessleg length discrepancy (LLD) which will affect pelvic motion and stride length. Note: LLD < 1.5 cm is usually not significantprolonged or delayed pronation or supination of the foot, which will alter the function of the leg and pelvis during the running cycle
18Intrinsic and extrinsic factors Poor muscular co-ordination Running requires strength, power, endurance and co-ordination. Problem-free running cannot take place if the hamstrings are weak, inflexible, or if there is poor neuromuscular co-ordination. Loss of the normal ratio of muscle power between the quadriceps and hamstrings may also occur. The normal quadriceps/hamstrings ratio is 60:40. Loss of the normal ratio may be due to excessive development of the quadriceps, or due to existing weakness of the hamstrings. A normal ratio is essential to prevent imbalances from occurring during the running cycle.
19Inappropriate training “Inappropriate” comprises all the factors that may affect your body’s ability to adapt to the varied stresses of running. Factors include:excessive mileagerapid increase in mileageinadequate warm-up and cool-downpoor stretchingcambered running surfacesworn shoes or orthotics
20Fatigue Fatigue affects performance and may predispose you to injury. At a physiological level, fatigue may be reflected in a prolonged recovery time at neuromuscular junctions, which diminishes effective muscle activation, slows the clearing of metabolites from the muscle, and impairs the ability of the muscle to contract. Fatigue therefore results in decreased strength, power and endurance, and will increase the risk of injury.
21Incomplete rehabilitation As runners, we are always eager to get back on the road as soon as possible. If an injury is not properly treated, or if you do not achieve your pre-injury levels of strength, endurance and flexibility, the risk of re-injury is increased. Effective rehabilitation (which means putting in the time with the physio, or at the gym) will allow you to get back on the road and stay there.
22Repeated micro-trauma Often trauma to the hamstrings may not always be significant enough to cause pain or disability at the time of injury.The reduction in hamstring function may be so gradual that it will not be detected until there is a serious problem. This is often described as “the last straw that broke the camel’s back”, where repeated micro-trauma will finally result in pain and dysfunction. When running, the hamstrings are often exposed to repeated micro-trauma due to over-striding, as well as with a change of pace. Over-striding, particularly when just starting to run downhill, places the hamstrings under excessive eccentric load as the muscle works to stabilise the knee joint. The excessive eccentric load may result in micro-trauma to the muscle fibres, leading to injury.
24Muscle InjuryWhat are the consequences to the athlete of not treating a muscle injury correctly?How much damage is caused by inactivity on the athletes and the doctors part?Why is there no/little consensus on management of muscle injury?
25Staring point with an Hamstring lesion R.I.C.E Compression the key Gentle mobilisation Partial weight bearing as tolerated Electrotherapy modalities When to stretch? When to start running again?
26Continued Rx STR / MFR Acupuncture NSAIDs after 24 hours Electrotherapy modalitiesCorrect Physical rehabilitation is paramount in the management of hamstring injuries
27Early mobilisation versus strength/stretching Two rehabilitation programsStatic stretching and progressive strengtheningProgressive agility and lumber stabilisation programNo stat difference in RTS timesStat difference in recurrence rates over I year period remain ISQ (Sherry et al, JOSPT, 34(3): )
28Where basic science and clinical guidelines collide Perception is that early mobilisation is against basic principles.RICE principle for 7 days minimises pain, swelling to offer best possible conditions for healing process. Kannus et all (2003)Studies cited were for non-contractile tissues (ie ligaments)Prolonged immobilisation is detrimentalEarly mobilisation of affected tissue increases density of scar formation. (Jarvinen, 1975) What about remodelling???
29Accelerated running program Developed by Graham ReidAustralian Hockey PhysioInjured player on tourCaptive audienceGood result
30Accelerated Running Program Day 0:Ice, Electro modalities, +/- CPM, +/-Ice, Compression etcDay 1:Continue as above.When range in sitting position (Lordotic spine) at 120 or - 10 degrees off full knee extension ? start running program
31Progressive Running Program Graham Reid Jogging at variable speed up to 75%Minimal acceleration/decelerationApprox 4 min/km paceUp to 2 kmsVariable distances 100mx3, 90mx3, 80mx3, 70mx3, 60mx3, 50mx3, 40mx3, 30mx3: Repeat x 2Backwards running: 50 x 3 , 75 x 6, 40 x 3
32Progressive Running Program Graham Reid Once at 75% without pain, start acceleration program40 – 20 –40–35
33Summary of running program Aggressive but controlled rehabTakes out a lot of the guess work with training loadsMany variations – needs to be tailored to the sport and then the individual athleteAddressing causative factors is the most important aspect to hamstring rehabilitation
34My approach to pre running criteria (how do you know when the athlete can run ????)Adductor magnus bridges 5 sets of 12 repsSeated knee extension = 10 degrees off straightSingle leg long level bridge = pain free
37Why does early mobilisation work? Eccentric exercise in a controlled way is functionalImproved neural patterning/technical abilityAllows progression as quickly as possible with consistent feedbackCPM effect- decreases disorganised collagen formation. Maintain extensibility of the muscleHamstring strains are almost never isolated strainsStrengthening in a functional way
38Recurrences Scar at its weakest point 10-12 days after injury Time frames will vary - forced by time constraintsAnalogous to ACL return at 6 months
39Injury prevention Extremely difficult! The hamstring strains occurring in sprinters during maximalthe sprinter’sstrain involving primarily muscular tissue, and the dancer’sstrain more proximal tendinous tissue.speed running caused a more striking acute decline infunction, but had a faster recovery time than those occurringin extreme positions during stretching exercises in dancers.Interestingly, there were no correlations between time toreturn to pre-injury level and the magnitude of the acute lossor short term recovery of hip flexibility or knee flexionstrength.The injury seems to berelated to the magnitude of force, rate of force development,and/or length change rather than extreme joint positions.13
40Eccentrics??? Concentric Eccentric Characteristics of eccentric contractionProduces more force than concentricsSelectively recruits Fast fibers. Fast fibers are bigger and have greater potential for growth than slow fibers.During the eccentric phase of movement, the muscle absorbs energy. This work is done “by stretching the muscle and in this process the muscle absorbs mechanical stress This mechanical energy is dissipated or converted into one or a combination of two energies.1. Heat2. Elastic Recoil
41Key concepts in injury prevention Improve the training regime so that it more accurately reflects sports specific conditions with the goal of improving muscle conditioning;Try and improve fatigue resistance of the hamstring muscleTry and induce a change in the viscoelastic properties of muscle so as to increase energy absorption and decrease load on the muscle-tendon unit for any given length especially in body positions of function and vulnerability to injury. Verrall et al 2005 Br J Sports Med
42Can we predict/prevent hamstring strains? Previously injured muscles developed peak torque at significantly shorter range than uninjured muscles Peak torque and quad / hamstring torque ratios were not significantly different Eccentric exercise possibly shifts length-tension curve to the right Most Studies used concentric measurements, Why when we know hamstrings have an eccentric action? (Brockett et al, 2004: Med Sci Sports & Ex. 36(3))
43Predicting/ Preventing muscle strains Role of screeningHamstring rangeStrength components (Isokinetic)Joint rangesTraditionally, our biggest predictive factor to hamstring strains is previous history of hamstring strain.
44Can we predict/prevent hamstring strains? Decreased incidence in soccer players on an eccentric programAskling et al (2003): Scand. J. Med. Sci. Sports 13:Decreased hours lost, no of injury and weeks out with intervention program (Verral, BJSM 2005)
45Incremental Increase in Eccentric Exercise Drop-catch exercises (Stanton and Purdam 1989 J Orthop Sports Phys Ther) Nordic hamstrings High-velocity eccentric exercises in the final phase of rehabilitation (Geraci 1998)Stanton and Purdam6 describe“drop-catch” exercises in the prone position with the hipin flexion or with the athlete lying over the edge of atable. Quick active knee extension is followed by rapiddeceleration via hamstring eccentric contraction, followedby rapid concentric contraction. The athlete progressesfrom slow catches to faster velocities over severaltraining sessions. Light weights can be added to theankle with the athlete returning to slower catches witheach higher weight before progressing to faster catches.
50Points to consider in Footballers Body awarenessRequirements of the SportLimited neural aspectsLimited kicking etc. till full runningBall work restricted in initial stagesPhysical rehabilitation does not replace intensive hands-on approachHow to integrated this philosophy with the football management
51Sports Specificity relating to hamstring injury prevention Think specific and genericie FootballLaddersChange of directionBackwards/sideways runningShuttlesChase and escape drillsRecreate load, stress, strain, joint angles, fatigue index
52Case Study Primary hamstring lesion grade 1+ on US Day 1 PRICE crutches 2/7 no NSAIDsDay 3STR / PNF local electrotherapy + NSAIDsSeated SLR / passive mobilisationsDay 5 programActive mobilisations / basic gym programDay 7Hamstring specific program (powerpoint)
53Re US scan good reduction in fluid RTP day 18 Post injury Case Study ContdDay 14Re US scan good reduction in fluidRTP day 18Post injuryS&C lead eccentric program in place and a physio lead pelvic neuromuscular patterning program with monitoring
54Summary Diagnosis is key, use correct imaging modalities Initial treatment is in line with any other soft tissue injury; protection, RICE and early mobilisation.Understand that there is close relationship between hamstring injury, the neural system and lumbar spine pathology
55Apply an eccentric injury prevention strategy Summary continuedAccelerated running programs can be utilisedIdentify predisposing factors relating to the hamstring injury in that individual athleteApply an eccentric injury prevention strategyDevelop your own strategy related to current research evidenceBe sports specific in your approach
57ReferencesKyro ̈ la ̈ inen H, Komi PV, Belli A. Changes in muscle activity patterns and kinetics with increasing running speed. J Strength Cond Res 1999;13:400–6.Pinniger GJ, Steele JR, Groeller H. Does fatigue induced by repeated dynamic efforts affect hamstring muscle function? Med Sci Sports Exerc 2000;32:647–53.Garrett WE. Muscle strain injuries: clinical and basic aspects. Med Sci Sports Exerc 1990;22:436–43.Best TM. Soft-tissue injuries and muscle tears. Clin Sports Med 1997;16:419–34.Stauber WT, Knack KK, Miller GR, et al. Fibrosis and intercellular collagen connections from four weeks of muscle strains. Muscle Nerve 1996;19:423–30.Stauber WT, Smith CA, Miller GR, et al. Recovery from 6 weeks of repeated strain injury to rat soleus muscles. Muscle
58ReferencesAskling C, Saartok T, Thorstensson A. Type of acute hamstring strain affects flexibility strength and time back to pre-injury level. Br J Sports Med. 2006;40:40-44.Askling C, Tengvar M, Saartok T, Thorstensson A. Sports related hamstring strains—two cases with different etiologies and injury sites. Scand J Med Sci Sports. 2000;10:Brooks JHM, Fuller CW, Kemp SPT, Reddin DB. Incidence, risk, and prevention of hamstring muscle injuries in professional rugby union. Am J Sports Med. 2006;34:Connell DA, Schneider-Kolsky ME, Hoving JL, et al. Longitudinal study comparing sonographic and MRI assessments of acute and healing hamstring injuries. AJR Am J Roentgenol. 2004;183:De Smet A, Best T. MR imaging of the distribution and location of acute hamstring injuries in athletes. AJR Am J Roentgenol. 2000;174:Gabbe BJ, Bennell KL, Finch CF, Wajswelner H, Orchard JW. Predictors of hamstring injury at the elite level of Australian football. Scand J Med Sci Sports. 2006;16:7-13.Garrett WE, Rich FR, Nikolaou PK, Vogler JB III. Computed tomography of hamstring muscle strains. Med Sci Sports Exerc. 1989;21:Gibbs NJ, Cross TM, Cameron M, Houang MT. The accuracy of MRI in predicting recovery and recurrence of acute grade one hamstring muscle strains within the same season in Australian Rules football players. J Sci Med Sport. 2004;7: