Muscles, motor control and spinal stability

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Muscles, motor control and spinal stability

• Gail Nankivell
• Physiotherapist
• The Childrens Hospital at Westmead

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Overview

• Stability
• Model of Function
• Motor Control
• Muscle Systems

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What is Stability?

• Ability of the neuromuscular system to control
  and protect the spine (joint) from injury or
  reinjury
• Hodges 2003

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Spinal stability

• 1.Control of spinal orientation - maintenance of
  overall spinal posture
• 2.Control of inter segmental relationship of each
  lumbar segment and the pelvis

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Strategies for stability

• Muscle capacity
• Strength
• Endurance
• Bracing and co contraction

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Strategies for stability

• Muscle Control
• Coordination sequencing of activation
• Control
• Timing
• ? Right muscle at right time with the right
  amount of force

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Integrated Model of Function
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Integrated Model of Function
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Integrated Model of Function
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Integrated Model of Function
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Integrated Model of Function
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Integrated Model of Function
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Physical Examination

• Posture and movement analysis
• - static
• - functional
• Specific examination (active manual)
• Examination of nervous system

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Physical Examination

• Local muscle system
• - tests of muscle control
• - task-specific tests
• - strength endurance
• Sensorimotor control
• - joint position sense
• - balance
• Work/functional tasks

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Motor control

• Patterning or timing of muscle action inaction
• Coordinated muscle action for stability motion
  control
• Restoration of motor control
• ? exercises that sequence muscle activation
• Imagery to restore neural patterning increase
  strength
• (Comerford Mottram 2001Daneels et al 2001
  Hodges et al 1996,2000)
• (Lee 2001Richardson et al 1999)
• (Gandevia 1999 Yule Cole 1992)

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Muscle Systems

• Global regional stabilisation
• Local segmental and intrapelvic stabilisation
• Some muscles belong to both systems depending on
  the task.
• (Bergmark 1989)

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Muscle systems
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Muscle systems - Global
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Muscle systems - Global

• Action is direction specific
• Generate torque and control motion
• concentrically
• isometrically
• eccentrically

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Muscle systems - Global

• Maintains postural orientation
• Maintains equilibrium
• Produces power
• Facilitate by using verbs or instructions.

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Muscle systems - Global

• Integrated sling system
• Muscles may overlap and interconnect, depending
  on the task
• Slings may all be part of one interconnected
  system
• (Vleeming et al 1995 Snijders et al 1995)

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Global System - Dysfunction

• Weakness
• Non recruitment or delay
• Tightness / change in muscle length
• Imbalance in muscle activity
• Muscles may be over active

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Muscle System - Local
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Muscle System - Local

• Maintain a continuous low activity
• Increase in action prior to increase load or
  motion
• Is not direction specific
• Fine tunes interspinal segments
• Anticipatory
• Facilitate with use of imagery
• Muscles recruit best in neutral spine

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Muscle System

• When the local system works correctly
• Applies compression to pelvis (form closure)
• Pelvis then ready to accept load from global
  system

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Transverse abdominis
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Transversus Abdominus

• Anticipatory for stabilisation of low back and
  pelvis prior to UL/LL movement
• Increases SIJ stiffness via thoracodorsal fascia
  (with multifidus)
• Helps stabilise pubic symphysis with
  pubococcygeus
• Contracts in response to PF contraction
• (Hodges Richardson 1996,1997)
• (Richardson et al 2002 Barker Briggs 1999)
• (Sapsford et al 2001)

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Dysfunction of TrA

• Timing delay or absence in patients with LBP
• Loss of intrapelvic stability(SIJ Pubic
  Symphysis)
• (Hodges Richardson 1997,1999,Hodges 2001)

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Multifidus
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Multifidus

• Deep superficial fibres
• Anticipatory for stabilisation of lumbar spine
  prior to UL initiation
• Deep fibres bulge to tighten TDF
• Superficial fibres direction dependent
• Co-contraction with TrA ( fascia) -circle of
  integrity
• Control of sacral position (with PF)
• (Moseley et al 2002)
• (Gracovetsky 1990, Vleeming et al 1995)
• (Richardson et al 2002)

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Multifidus - dysfunction

• Atrophies delayed or absent in patients with
  low back pain pelvic pain
• Retrain hypertrophy to rehabilitate
• (Hides et al 1994 1996Daneels et al 2000,
  2001OSullivan 1997,2000 Hungerford
  2002Moseley et al 2002)

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Pelvic floor
Pelvic floor
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Pelvic Floor

• Stabilisation of pelvic girdle
• - pubic symphysis
• - sacral position( with multifidus)
• Maintenance of urinary faecal continence
• Supports internal pelvic organs
• (Ashton Miler et al 2001 Bo Stein 1994
  Contantinou Govan 1982 Diez et al 2003
  Peschers et al 2001 Sapsford et al 2001)

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Pelvic Floor

• Contracts in response to hollowing bracing
  command
• Can facilitate PF by co activating abdominals
  vice versa
• Reflex connection between PF urethra
• (Sapsford et al 2001Constantinou Govan 1982)

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Pelvic Floor - Dysfunction

• Incontinence - urinary faecal
• Loss of intrapelvic stability

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Diaphragm
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Diaphragm

• Stabilizer of the trunk for postural support
• Anticipatory with TrA prior to shoulder flexion
• (Hodges 19972000)

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Diaphragm

• Diaphragm EMG
• - increased tonic activity
• - phasic modulation with respiration
• - phasic modulation with movement

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Diaphragm
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Diaphragm

• Loss or reduction of tonic function ( phasic
  modulation associated with arm movement) of
  diaphragm TrA after 60 seconds of hypercapnoea
• (Hodges 2001)

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Local System Dysfunction

• Timing
• Atrophy
• Loss of Tonic function
• Loss of coordination with other local muscles
• Asymmetry

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Thorax

• Integrated model of function
• Stability motor control
• Role in UL function, neck, lumbopelvic LL
  function
• Global local muscle systems
• Control of scapula glenohumeral joint

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Thorax

• Longissimus multifidus activity during seated
  rotation
• Longissimus direction specific
• Multifidus- No difference between directions at
  T5
• (Lee,Coppieters Hodges Spine 2005)

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Cervical Spine

• Deep neck flexors vs. SCM scalene
• Loss of recruitment of DNF in patients with neck
  pain
• Greater co activation of superficial neck flexors
  extensors in neck pain
• Inability to relax muscles after completion of
  task
• (Jull et al 2007)
• (Johnston et al 2007)

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Retraining the Core

• Neutral Spine is best position to learn
  recruitment of core muscles (Sapsford 2001)
• Post pelvic tilt position will recruit external
  obliques
• TA best recruited in neutral or slightly
  excessive lordosis (ant pelvic tilt)

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Postural Re-education

• In crook lying
• Sitting- reset the pyramid base
• Side lying
• Prone
• Standing
• One leg stance (load transference)

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Retrain the Core

• Downtrain/relax the global system
• Isolate the muscle
• Train for endurance co-contraction with other
  muscles of the core
• Maintain neutral position and add load
  (trunk-legtrunk-arm dissociationball)

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Retrain the Core

• Co-contact the entire core then integrate into
  functional positions
• Once local system working well integrate/retrain
  breathing patterns
• Coordinate with global system (ie move in out
  of neutral spine flex, extend, rotate .. without
  segmental or regional collapse)

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TA PFimagery cues

• Draw the ASIS together (string, wire)
• Vaginal lift, testicular lift
• Tension (or string) from inner thigh up into the
  pelvic floor
• String betw PS coccyx
• PF squeezes lifts

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Multifidus imagery cues (Lee)

• Draw the PSIS s together (a force,line)
• Pelvic floor
• Barbie doll leg pulled off- use a force coming
  from inside groin to connect it back into the
  socket.
• Wire/strings Groin-MFPS-MFLeg-MFASIS-MFPF-MF

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Patterning of mm recruitment in OLS (controls)

• PriorTransverse fibres OI multif then
  feedforward activation of TrAtrans fibres OI
  multif to stabilise interseg lumbar motion and
  TrA OI facilitate post rotation of
  inominate,multif activation for sacral nutation
  SIJ close pack position

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Mm recruitment in OLS

• Glut max, glut med, add long TFL activate after
  initiation of motion- they maintain hip pelvic
  alignment during single leg support
• Biceps fem activity decreased during single leg
  support

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Assessment of Load Transfer thru pelvis

• Forward flexion test-Standing
• Stork Test (Gillet or one leg standing test)

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