muscles, motor control and spinal stability gail nankivell physiotherapist the children’s hospital...
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Muscles, motor control and spinal stability
Gail Nankivell
Physiotherapist
The Children’s Hospital at Westmead
What is Stability?
Ability of the neuromuscular system to control and protect the spine (joint) from injury or reinjury
Hodges 2003
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
Strategies for stability
Muscle Control Coordination & sequencing of
activation Control Timing
→Right muscle at right time with the right amount of force
Physical Examination
Posture and movement analysis
- static
- functional Specific examination (active & manual) Examination of nervous system
Physical Examination
Local muscle system- tests of muscle control
- task-specific tests
- strength & endurance
Sensorimotor control- joint position sense
- balance
Work/functional tasks
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 2001;Daneels et al 2001; Hodges et al 1996,2000)(Lee 2001;Richardson et al 1999)
(Gandevia 1999; Yule & Cole 1992)
Muscle Systems
Global: regional stabilisation Local: segmental and intrapelvic
stabilisation
Some muscles belong to both systems depending on the task.
(Bergmark 1989)
Muscle systems - Global
Action is direction specific Generate torque and control motion
concentrically isometrically eccentrically
Muscle systems - Global
Maintains postural orientation Maintains equilibrium Produces power Facilitate by using verbs or instructions.
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)
Global System - Dysfunction
Weakness Non recruitment or delay Tightness / change in muscle length Imbalance in muscle activity Muscles may be over active
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
Muscle System
When the local system works correctly Applies compression to pelvis (form
closure) Pelvis then ready to accept load from
global system
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)
Dysfunction of TrA
Timing delay or absence in patients with LBP
Loss of intrapelvic stability(SIJ & Pubic Symphysis)
(Hodges & Richardson 1997,1999,Hodges 2001)
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)
Multifidus - dysfunction
Atrophies & delayed or absent in patients with low back pain & pelvic pain
Retrain & hypertrophy to rehabilitate
(Hides et al 1994 1996;Daneels et al 2000, 2001;O’Sullivan 1997,2000; Hungerford 2002;Moseley et al 2002)
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)
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 2001;Constantinou & Govan 1982)
Diaphragm
Stabilizer of the trunk for postural support
Anticipatory with TrA prior to shoulder flexion
(Hodges 1997;2000)
Diaphragm
Diaphragm EMG :- increased tonic activity
- phasic modulation with respiration
- phasic modulation with movement
Diaphragm
Loss or reduction of tonic function (& phasic modulation associated with arm movement) of diaphragm & TrA after 60 seconds of hypercapnoea
(Hodges 2001)
Local System Dysfunction
Timing Atrophy Loss of Tonic function Loss of coordination with other local
muscles Asymmetry
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
Thorax
Longissimus & multifidus activity during seated rotation
Longissimus direction specific Multifidus- No difference between
directions at T5(Lee,Coppieters & Hodges Spine 2005)
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)
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)
Postural Re-education
In crook lying Sitting- reset the pyramid base Side lying Prone Standing One leg stance (load transference)
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-leg;trunk-arm dissociation;ball)
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)
TA & PF–imagery 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
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-MF;PS-MF;Leg-MF;ASIS-MF;PF-MF
Patterning of mm recruitment in OLS (controls)
Prior:Transverse fibres OI & multif ; then feedforward activation of TrA;trans 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
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
Assessment of Load Transfer thru pelvis
Forward flexion test-Standing Stork Test (Gillet or one leg standing
test)