Hamstring Injuries

Paul Thawley MSc, BSc (Hons), PgDip (Rehab), MCSP SRP

Senior Sports Physiotherapist Team GB

“Hamstring injuries occur in all sports and effect elite and non elite populations” (Brooks et al 2006)

Athletic Population

Non Athletic population

Epidemiology

FA 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)

Epidemiological 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 injury

Biceps femoris most commonly injured

Increased incidence with age

Epidemiology

Posterior Thigh Pain: Differential Diagnosis

Hamstring muscle strain; Acute / Chronic

Hamstring muscle contusion

Referred from Lx

Neural structures; Triggers points

Less Common Posterior thigh painReferred from SIJ

Tendinopathy

Bursitis

Compartment syndrome

Apophysitis

Nerve entrapment

Adductor magnus

Myositis Ossificans

Not to be missedTumors

Iliac artery insufficiency

Diagnosis

Listen Hx is key

LookMove FeelSpecial tests

Neural Dynamics

Slump test as a diagnostic tool

Slump as a treatment modality

Significant effect on Fascia – Vleeming et al 2005

Lumbar Spine

Age / 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:10.1186/1746-1340-13-4

If your think the lesion is soft tissue Dynamic Ultrasound or MRI are you

investigations of choice

Common mechanism Late swing phase in

running action

Eccentric contraction to decelerate the shank

Often accentuated in preparation to jump, kick

Trunk flexion whilst running (Verral, 2005)

Other mechanisms

Stretch with knee fully extended (stretching for a ball, kicking)

Forced trunk flexion with foot planted (waterskiing)

Possible causes of Muscle Injury

Musculoskeletal imbalances

Poor muscular co-ordination

Inappropriate training

Fatigue

Incomplete rehabilitation

Repeated micro-trauma

Musculoskeletal imbalances

Any 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

Intrinsic and extrinsic factors

Poor muscular co-ordinationRunning 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.

Intrinsic and extrinsic factors

Inappropriate 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

FatigueFatigue 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.

Incomplete rehabilitationAs 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.

Repeated micro-traumaOften 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.

Treatment approaches

Muscle Injury

What 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?

Staring 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?

Continued Rx

STR / MFRAcupunctureNSAIDs after 24 hoursElectrotherapy modalities

Correct Physical rehabilitation is paramount in the management of hamstring injuries

Early mobilisation versus strength/stretching Two rehabilitation programs

Static stretching and progressive strengtheningProgressive agility and lumber stabilisation program

No stat difference in RTS times

Stat difference in recurrence rates over I year period remain ISQ (Sherry et al, 2004. JOSPT, 34(3): 116-25)

Where 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 detrimental

Early mobilisation of affected tissue increases density of scar formation. (Jarvinen, 1975) What about remodelling???

Accelerated running program

Developed by Graham Reid

Australian Hockey Physio

Injured player on tour

Captive audience

Good result

                         

Accelerated Running Program

Day 0:

Ice, Electro modalities, +/- CPM, +/-Ice, Compression etc

Day 1:

Continue as above.

When range in sitting position (Lordotic spine) at 120 or -10 degrees off full knee extension ? start running program

Progressive Running ProgramGraham ReidJogging at variable speed up to 75%

Minimal acceleration/deceleration

Approx 4 min/km pace

Up to 2 kms

Variable distances 100mx3, 90mx3, 80mx3, 70mx3, 60mx3, 50mx3, 40mx3, 30mx3: Repeat x 2

Backwards running: 50 x 3 , 75 x 6, 40 x 3

Progressive Running ProgramGraham Reid

Once at 75% without pain, start acceleration program40 – 20 –4035- 20 –3530-20-3025-20-2520-----2015-----15

Summary of running program

Aggressive but controlled rehab

Takes out a lot of the guess work with training loads

Many variations – needs to be tailored to the sport and then the individual athlete

Addressing causative factors is the most important aspect to hamstring rehabilitation

My approach to pre running criteria (how do you know when the athlete can run ????)

Adductor magnus bridges 5 sets of 12 reps

Seated knee extension = 10 degrees off straight

Single leg long level bridge = pain free

Hamstring Exercises

Manual resistance

Manual therapy

Rehabilitation approach

Why does early mobilisation work?

Eccentric exercise in a controlled way is functional

Improved neural patterning/technical ability

Allows progression as quickly as possible with consistent feedback

CPM effect- decreases disorganised collagen formation. Maintain extensibility of the muscle

Hamstring strains are almost never isolated strains

Strengthening in a functional way

RecurrencesScar at its weakest point 10-12 days after injury

Time frames will vary - forced by time constraints

Analogous to ACL return at 6 months

Injury prevention

Extremely difficult!

Eccentrics???

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

Key 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 muscle

Try 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

Can 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))

Predicting/ Preventing muscle strainsRole of screening

Hamstring range

Strength components (Isokinetic)

Joint ranges

Traditionally, our biggest predictive factor to hamstring strains is previous history of hamstring strain.

Can we predict/prevent hamstring strains?

Decreased incidence in soccer players on an eccentric program

Askling et al (2003): Scand. J. Med. Sci. Sports 13: 244-250

Decreased hours lost, no of injury and weeks out with intervention program (Verral, BJSM 2005)

Incremental Increase in Eccentric ExerciseDrop-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)

Hamstring Exercises

Nordic Hamstrings

research From: Bahr and Meahlum (2002)Icelandic curls

Length-tension relationship

Tension

Length

Icelandic curls

Tension

Points to consider in Footballers

Body awareness

Requirements of the Sport

Limited neural aspects

Limited kicking etc. till full running

Ball work restricted in initial stages

Physical rehabilitation does not replace intensive hands-on approach

How to integrated this philosophy with the football management

Sports Specificity relating to hamstring injury prevention

Think specific and genericie FootballLaddersChange of directionBackwards/sideways runningShuttlesChase and escape drills

Recreate load, stress, strain, joint angles, fatigue index

Case Study

Primary hamstring lesion grade 1+ on USDay 1PRICE crutches 2/7 no NSAIDsDay 3STR / PNF local electrotherapy + NSAIDsSeated SLR / passive mobilisationsDay 5 program Active mobilisations / basic gym programDay 7Hamstring specific program (powerpoint)

Case Study Contd

Day 14 Re US scan good reduction in fluid

RTP day 18Post injuryS&C lead eccentric program in place and a physio lead pelvic neuromuscular patterning program with monitoring

Summary

Diagnosis is key, use correct imaging modalitiesInitial 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

Summary continued

Accelerated 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

Questions/comments/discussion?

Kyro O la O 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

References

References Askling 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;10:304-307.

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;34:1297-1306.

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;183:975-984.

De Smet A, Best T. MR imaging of the distribution and location of acute hamstring injuries in athletes. AJR Am J Roentgenol. 2000;174: 393-399.

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;21:506-514.

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;7:248-258.