Muscle Injuries at FISIC 2017

On the 27th & 28th September 2017, staff and students from Plymouth Marjon University went up to the Fortius International Sports Injury Conference in London.

Over the 2 days there were some fantastic, inspirational break out sessions. Here, Sarah Martin (Lecturer in Sports Therapy & Rehabilitation, & Programme Leader for the MSc Sport Rehabilitation) shares her notes on the Muscle Injuries breakout session.

An excellent presentation by Justin Lee demonstrated  British Athletics have encouraging use of their Muscle Injury Classification System – Grade 0, 1, 2, 3 & 4 (Pollock et al., 2014). This has since been observed for its reliability (Patel et al., 2015).

The classification is made depending on the severity and site of the injury. Grade 0 have normal MRI results and clinically present as generalised muscle soreness. Grade 1 injuries are minor tears where the athlete usually presents with pain during or after activity. Their ROM will be normal after 24 hours but there may be pain on contraction, although strength and initiation of contraction will appear normal on examination. Grade 2 injuries are moderate tears to the muscle which usually present with pain during activity where the athlete needs to stop activity. The ROM is usually limited after 24 hours, with pain on initiation of contraction, usually with an apparent weakness on strength assessment. Grade 3 injuries are extensive tears to the muscle. The athlete usually presents with sudden onset pain and may fall to the ground. ROM after 24 hours is significantly reduced and the athlete has pain on walking with obvious weakness in contraction. Grade 4 injuries are complete tears to the muscle or the tendon (grade 4c). Sudden traumatic onset of pain, a palpable gap is felt but less pain on contraction than a grade 3 presents with.

The site of injury is determined as illustrated below:

Muscle Injury Classication (Pollock et al., 2014)

Some examples:

Grade 2A – myofascial; CC length 5-15cm, CSA 10-50%, Normal Tendon

Grade 2C – MTJ; CC length 5-15cm, Oedema CSA 10-50%, Abnormal tendon = <50% CSA, <5cm length, no loss of tension

Grade 3C – MTJ; CC length >15cm, Oedema CSA >50%, Abnormal tendon = >50% CSA, >5cm length, loss of tension

Grade 4C – rupture of muscle or tendon, loss of tension with retraction

Note – muscle oedema not reliably assessed on ultrasound; 50% of grade 1 injuries have normal ultrasound examination.

However, tendon involvement can be reliably assessed on ultrasound. %CSA involvement & length is easily observed but loss of tension may be difficult to identify. Full thickness tendon tear ends may be obscured by Haematoma so MRI may be more beneficial (Connell et al., 2004).

Peetron (2002) devised a useful Grading System on Hamstring Injuries which has since been modified.

Key considerations when ultrasounding acute muscle injury:

·         Can’t reliably assess oedema

·         Can’t reliably assess loss of tension

·         Can assess percentage CSA involvement of tendon

·         Can assess length of tendon involvement

·         May not be able to identify retracted tendon ends if complex haematoma present

Rob Chakravety highlighted the key factors which hold an athlete back during rehabilitation:

·         Tissue healing

·         Pain

·         Strength

·         Intolerance to load

·         Suboptimal movement patterns

There is a need to promote and focus on:

·         Regeneration – PRP?

·         Inflammation control – PRP or Traumeel

·         Nociception – afferent signals, muscle inhibition -  Trp’s injected with Traumeel or Local Anaesthetic

·         Peripheral inhibition - afferent signals, muscle inhibition -  Trp’s injected with Traumeel or Local Anaesthetic

·         Central inhibition – spinal inflammation of longitudinal ligaments leads to pressure on dura; inject with kenalog, an anti-inflammatory with saline to wash away inflammatory mediators

·         Ligamentous instability – inject with dextrose or P2G

·         Musculoskeletal dysfunction – e.g. lack of DF, muscle overload or TrP’s – inject with Traumeel or Osteril

Key point – the evidence base for injection is SPARCE!

Noel Pollock from British Athletics then discussed the assessment and management of recurrent ‘Calf Strains’. 5 key points for consideration are:

·         Accurate diagnosis –

o   Structural Diagnosis

§  Clinical assessment, imaging & imaging videos (mechanism of injury).

§  Don’t miss a plantaris rupture for calf pain. Also consider sural nerve & lumbar referral, popliteal artery entrapment syndrome (especially those with a large head of gastroc). The new muscle classification system works well for soleus injury (Pezzotta et al., 2017).

o   Functional Diagnosis

§  Technical errors

§  Neural

§  Articular

§  Muscular imbalances and dysfunction

·         Medical Intervention

·         Rehabilitation

o   Consider the functional demands of the athlete (Lieber and Ward (2011) have an excellent paper which discusses muscle fibre length to meet functional demands). E.g soleus – fatigue resistance must be built in due to isometric nature of mm

·         Monitoring/Milestones

o   Consider Gabbett’s (2016) Injury Prevention Paradox to monitor risk

·         Return to Play

o   Role of the athlete, HCP and coach – essential reading by Dijkstra et al. (2017) in the British Journal of Sports Medicine on the decision making process for RTP

Dijkstra et al. (2017) - Decision-making process for RTP

British Athletics Muscle Injury for the calf:

a) Myofascial

                        Very low reinjury

Sore but functional, quick recovery

b) Muscle-Tendon Junction

                        Small injuries prone to reinjury

                        Gradual ‘traditional’ progression

c) Intratendinous

                        High reinjury rate

                  Manage tendon

Nick van der Horst presented his PhD research on hamstring injuries and return to play. HSI’s are the number 1 muscle injury in football (match incidence 22/1000 hours; training incidence 3.5/1000 hours). Recurrence rate is 12-33% and there is a frequent link to decrease performance following HSI (Hagglund et al., 2013). Despite an increase in research, there is still an upward trend for Hamstring Injuries (by 4% annually for the last 13 years (Ekstrand et al., 2016)). 50% of all recurrences occur within 1 month after RTP (Brooks et al., 2006; Wangensteen et al., 2016) which may be due to inadequate rehabilitation or premature RTP.

The decision to return to play should be multidisplinary (Athlete, team coach, physical therapy, sports physician and fitness trainer should all have an input). The Return to Play Criteria is suggested below:

The widely publicised Strategic Assessment of Risk and Risk Tolerance (StARRT) Framework is imperative in the return to play process (Shrier, 2015).

Craig Ranson discussed the role of prehabilitation and rehabilitation in muscle injuries. He highlighted a recent debate in the press with Arsene Wenger describing cryotherapy as ‘smoke and mirrors’ as he questioned its’ effectiveness, the lack of evidence base for many of our treatment modalities and why muscle problems are still taking 21 days for return to play, the same timescale as 30 years ago. He also highlighted the shortly available MRI scan of Usain Bolts hamstring strain in the infamous incident of Bolt’s last race.

Workload patterns are directly related to injury, but it is difficult to calculate workload (Bourdon et al., 2017; Williams et al.,2017). Strength should be measured through isokinetics, Nordbord, Single Leg Bridge Test (Freckleton et al., 2014).

Factors attributing to muscle injury include:

·         Sleep

·         Previous injury

·         Inadequate preparation

Rehabilitation must exceed pre-injury state to address probable pre-existing weakness. Context-specific exercises are imperative including OKC functional activities. In the early stage, stair running in the first 7-10 days as there is very little hamstring and calf activation. Askling Test for RTP should be used (Erickson and Sherry, 2017). Acute-Chronic Workload models must also be monitored and considered (Bowen et al., 2016; Hulin et al., 2016; Murray et al., 2016).

James Moore concluded the session by discussing factors which may speed up the RTP process. Key decisions include:

·         Effective differential diagnosis and classification

·         1^st 48 hours is critical – do not be afraid to offload with crutches

·         Athlete profile

·         Sport profile

·         Athlete specific clinical outcome measures

·         Define the end point early

·         Need to pass clinical measures at each stage (stretch, force, palpation)

·         Capacity Assessment within the rehab

The injury continuum includes mechanism, type, location and size and should be considered in all cases.

E.g Injury profile/classification for a Quad Injury – consider how these variables interact with each other:

·         Mechanism

o   Under striding vs bwd lean vs Hip Extension vs backswing vs VGRF

·         Sports Mechanism

o   Sprinting vs kicking (high vs low velocity of limb movement)

·         Location

o   Proximal vs Mid vs Distal/Tendon vs Muscle vs Fascia

·         Size / Grade

o   0, 1, 2, 3, 4 (a, b, c)

·         Functionality

o   Of the region (architecture) vs the individual (kinetics) vs sport specific

Typical vs Atypical Hamstring Injury?

Typical:

·         Proximal BF in terminal swing phase at speed

·         Distal medial hamstring on stance phase (sprinting)

·         Proximal SM in stance on rapid stretch

Atypical:

·         Distal BF on stance phase (running)

·         BF muscle belly alone

·         Proximal Medial hamstring (SM) in swing phase (sprinting)

Muscle Architecture should be relevant to the rehabilitation, and how the muscles work synergistically:

Muscle	Fibre Length (cm)	Pennation	PCSA (cm2)	Peak Force (N)	Tendon Slack
Gastroc – medial	5.1	9.9	21.4	1308.0	40.1
Gastroc – lateral	5.9	12.0	9.9	606.4	38.2
Soleus	4.4	28.3	58.8	3585.9	28.2
Tibialis Anterior	6.8	9.6	11.0	673.7	24.1
Peroneus Longus	5.1	14.1	10.7	653.3	33.3
Peroneus Brevis	4.5	11.5	5.0	305.9	14.8
Tibialis Posterior	3.8	13.7	14.8	905.6	28.2
FHL	5.3	16.9	7.2	436.8	35.6
FDL	4.5	13.6	4.5	274.4	37.8

In sports which require a change of direction, consider developing ankle power, PF moment and minimal ground contact time (Marshall et al., 2014).

In the first 48 hours:

·         Inflammation – friend or foe?

·         Avoid use of NSAID’s

·         Ice and compression critical

·         Early movement useful, but avoid stretching

·         Avoid direct soft tissue work

·         Avoid excessive travel

Muscle Stiffness regulated by:

·         Muscle activation frequency (temporal summation)

·         Muscle fibre recruitment (spatial summation)

·         Sarcomere length-tension relationship

·         Sarcomere force-velocity relationship

·         Passive sarcomere length-tension relationships

·         Intrafusal and extrafusal (muscle spindle) fibres feedback mechanism

·         Muscle force and moment regulation by skeletal muscle architecture

Early rehab activity:

·         Short period of immobilisation

·         Early resumption of activities during the repair and remodelling (Orchard & Best, 2002)

·         Initial loading within a protected MT length (Sherry & Best, 2004)

Agility & Stability

·         Progressive agility and trunk stabilisation > isolated stretching & strengthening (Sherry & Best, 2004)

·         Relative flexibility vs relative stiffness (Hamilton, 1996)

·         Direction of movement allows early loading of injured tissue and resumption of NM co-ordination (Sherry & Best, 2004)

·         Later stages plyometric activities NM co-ordination and prepare for rapid high load movements (Chmielewski et al., 2006)

Specific Loading

·         Atrophy greatest risk of re-injury after tissue healing (Orchard & Best, 2002)

·         Lower incidence of hamstring injury has been reported in athletes who undergo high load eccentric hamstring training (Askling, 2003)

·         Running – max peak torque coincides with eccentric activity occurring at late swing phase (Heiderscheit, 2005)

·         Following injury it shifts to shorter muscle lengths (Brockett, 2004)

·         HamSprint drills may reduce the risk of recurrence (Cameron, 2009)

·         High load eccentric training may shift the peak torque to longer lengths (Brockett, 2004)

McAllister et al.’s (2014) paper ‘Muscle activation during various hamstring exercises’ is an essential read.

Return to Running following Quad & Hams Injury (Freckleton, 2013)

·         Repeated bike sprint efforts

o   (>140rpm) 30s duration – Growth Hormone production (Stokes, 2010)

·         Single leg strength endurance challenge

o   1 leg Hack Squat vs Step Ups

·         Speed frequency loading in Quadriceps

o   Velocity & Volume

·         Drop Jump Capacity

Tendinopathy at FISIC 2017

On the 27th & 28th September 2017, staff and students from Plymouth Marjon University went up to the Fortius International Sports Injury Conference in London.

Over the 2 days there were some fantastic, inspirational break out sessions. Here, Sarah Martin (Lecturer in Sports Therapy & Rehabilitation, & Programme Leader for the MSc Sport Rehabilitation) shares her notes on the Tendinopathy breakout session.