Balance lecture& Postural Equilibrium

Dr.Afaf A.M Shaheenlecture 11RHS 322

Factors affecting balanceMuscular weaknessProprioceptive deficitsROM deficits

TerminologyBalance - Process of maintaining body’s CoG (Center of

Gravity) within base of supportAbility to align body segments against gravity to maintain or

move the body within the available base of support without falling .

Body’s CoG rests slightly above the pelvisStrength is emphasized before proprioception in rehab

because strength influences balance

Postural equilibrium - broader term that incorporates alignment of joint segmentsMaintaining CoG within the limits of stability (LOS)

TerminologyProprioception – body’s ability to transmit position sense,

interpret information & respond consciously/unconsciously to stimulation

Coordination – smooth pattern of activity is produced through a combo of muscles acting together with appropriate intensity & timing

Agility – ability to control the direction of a body or segment during rapid movement

Postural Control System

3 Components of the systemSensory detection of body motions

VisualVestibular Somatosensory inputs

Integration of sensorimotor information within the CNSExecution of musculoskeletal responses

Balance is both a static & dynamic process

Control of BalanceTall body vs. Small base of support

Balance relies on network of neural connectionsPostural control relies on feedback

CNS involvementSensory organization

Determines timing, direction & amplitude of correction based on input

System relies on one sense at a time for orientationMuscle coordination

Collection of processes that determine temporal sequencing & distribution of contractile activity

Sensory InputVision

Measures orientation of eyes & head in relation to surrounding objects

Helps maintain balance

VestibularProvides information dealing with gravitational, linear &

angular accelerations of the head with respect to inertial space

SomatosensoryProvides information concerning relative position of body

parts to support surface & each other

Somatosensation = Proprioceptive system

Specialized variation of the sensory modality of touch, encompassing joint sense (kinesthesia) & positionProcess•Input from mechanoreceptors•Stretch reflex triggers activation of muscles

Results in muscle response to compensate for imbalance and postural sway

•Muscle spindles sense stretch in agonist, relay information afferently to spinal cord•Information is sent back to fire muscle to maintain postural control

Body position in relation to gravity is detected by sensory input

Balance movements involve a number of joints Ankle Knee Hip Coordinated movement

along kinetic chain

Prentice, 2004, 4th ed.

Postural swayDeviation from Center of Pressure, Balance &

Vertical Force (CoP, CoB, or CoF)Determined using mean displacement, length of

sway path, length of sway area, amplitude, frequency and direction relative to CoP

Symmetry - Ability to distribute weight evenly between 2 feet in upright stance

Balance DisruptionBalance Deficiencies - Inappropriate interaction among 3

sensory inputs

2 Factors that Disrupt Balance Position of CoG relative to base of support is not accurately

sensed Automatic movements required to maintain the CoG are not

timely/effective

In the event of contact, the body must be able to determine what to do in order to control CoGJoint mechanoreceptors initiate automatic postural response

Selecting Movement Strategies during Balance Disruption

Joints (Ankle, Knee & Hip) involved allow for a wide variety of postures that can be assumed in order to maintain CoG

Instance of musculoskeletal abnormalityDamaged tissue result in reduced joint ROM

causing a decrease in the LOS & placing individual at a greater risk for fall

Research indicates that sensory proprioceptive function is affected when athletes are injured

Assessment of BalanceSubjective

AssessmentRomberg Test –

traditional assessment

Balance Error Scoring System (BESS)

Prentice, 2004, 4th ed.Google Images

Semi-dynamic & dynamic tests functional reach teststimed agility testscarioca hop testTimed T-band kicksTimed balance beam walks (eyes open &

closed)

Objective AssessmentBalance systems

Provide for quantitative assessment & training static & dynamic balanceEasy, practical & cost-effectiveUtilize to assess:

Possible abnormalities due to injury Isolate various systems that are affectedDevelop recovery curves based on quantitative measures in order to

determine readiness to returnTrain injured athlete

Computer interfaced force-plate technologyVertical position of CoG is calculatedVertical position of CoG movement = indirect measure of postural

sway

Prentice, 2004, 4th ed.

Force plate measuresAllows for static &

dynamic postural assessment

Single or double leg stance, eyes opened or closed

Dynamic stability - Ability to transfer vertical projection of CoG around a stationary supporting basePerception of safe limit of stability

Athlete should maintain their CoP near A-P and M-L midlines

Injury & BalanceStretched/damaged ligaments fail to provide adequate neural

feedback, contributing to decreased balance & proprioception May result in excessive joint loadingCould interfere with transmission of afferent impulsesAlters afferent neural code conveyed to CNSDecreased reflex excitation

Caused via a decrease in proprioceptive CNS input May be the result of increased activation of inhibitory interneurons within the

spinal cord

All of these factors may lead to progressive degeneration of joint & continued deficits in joint dynamics, balance & coordination

AnklesJoint receptors believed to be damaged during injury to lateral ligaments

Knee InjuriesLigamentous injury has been shown to alter joint position

detectionHead Injury

Balance Training

Vital for successful return to competition from lower leg injuryPossibility of compensatory weight shifts and gait changes

resulting in balance deficits

Functional rehabilitation should occur in the closed kinetic chain – nature of sport

Adequate AND safe function in the open chain is critical = first step in rehabilitation

Rules of Balance Training

Exercise must be safe & challengingStress multiple planes of motionIncorporate a multisensory approachBegin with static, bilateral & stable surfaces & progress to

dynamic, unilateral & unstable surfacesProgress towards sports specific exercisesUtilize open areasAssistive devices should be in arms reach early onSets and repetitions

2-3 sets, 15 → 30 repetitions or 10 of the exercise for 15 → 30 seconds later on in the program

Classification of Balance ExercisesStatic -

CoG is maintained over a fixed base of support, on a stable surface

Semi-dynamicPerson maintains CoG over a fixed base of support while

on a moving surfacePerson transfers CoG over a fixed base of support to

selected ranges and or directions within the LOS, while on a stable surface

DynamicMaintenance of CoG within LOS over a moving base of

support while on a stable surfaceFunctional

Same as dynamic with inclusion of sports specific task

Prentice, 2004, 4th ed.

Phase INon-ballistic types of drillsStatic balance trainingBilateral to unilateral on both

involved & uninvolved sidesUtilize multiple surfaces to

safely challenge athlete & maintaining motivation

With & without arms/counterbalance

Eyes open & closedAlterations in various sensory

informationIncorporation of multiaxial

devices Train reflex stabilization &

postural orientation

Phase IITransition from static to dynamicRunning, jumping and cutting – activities that require the

athlete to repetitively lose and gain balance in order to perform activity

Incorporate when sufficient healing has occurred Semi-dynamic exercised should be introduced in the

transitionInvolve displacement or perturbation of CoGBilateral, unilateral stances or weight transfers involvedSit-stand exercises, focus on postural

Bilateral Stance Exercises

Prentice, 2004, 4th ed.

Prentice, 2004, 4th ed.

Unilateral Semi-dynamic exercisesEmphasize controlled hip

flexion, smooth controlled motion

Single leg squats, step ups (sagittal or transverse plane)

Step-Up-And-Over activities

Introduction to Theraband kicks

Balance BeamBalance Shoes

Phase IIIDynamic & functional types of exerciseSlow to fast, low to high force, controlled to uncontrolledDependent on sport athlete is involved inStart with bilateral jumping drills – straight plane jumping

patternsAdvance to diagonal jumping patterns

Increase length and sequences of patternsProgress to unilateral drills

Pain & fatigue should not be much of a factorCan also add a vertical component to the drillsAddition of implements

Tubing, foam rollFinal step = functional activity with subconscious dynamic

control/balance

Phase III Exercises

Prentice, 2004, 4th ed.

The dynamic proprioceptive re-education consists of seven stages:-

1.Slow exercises followed by quicker movement

2.Exercise with limited effort followed by exercises requiring greater strength

3.Exercises requiring volition, followed by exercises done freely

4.Progress from walking to jogging

5.Running and sprinting

6.Jumping and changes of direction

7.Twirling and twisting around the injured or operated knee

Balance and control proprioceptive exercises

1.Stand on one leg.

2.Stand on one leg with eyes closed.

3.Stand on one leg – throw and catch a ball.

4.Stand on one leg – bend and straighten knee    

5. Stand on one leg- pick up item from floor.6. Hold knee dip – throw and catch a ball. 7. Stand on one leg – move other leg to side,

front and back.8. Push up onto toes (2 legs) and hold.  9. Push up onto toes with eyes closed.10.Push back onto heels, balance and hold.11. Push up on toes on one leg.

    

Walking proprioceptive exercises

1.Walk forward along a straight line. 

2.Walk on tip toes along straight line. 

3.Walk backwards along straight line.

4.Side step along straight line.  

5.Walk sideways crossing one foot over other (Cariocas).  

6.Walk fast in one direction, quickly changing direction at intervals.

Running proprioceptive exercises

1.Run fast in one direction.

2.Run backwards and do sidesteps.

3.Fast crossovers (Cariocas).

4.Run in figure of eight – make it smaller and smaller.    

5. Hopping on spot

6. Hop forwards and backwards – stop between hops.

7. Hop in zigzags.

8. Hop on and off step

9. Do triple jump - run, hop, jump and land.

• Balance and strength exercises are combined by incorporating light external forces and increasing the level of difficulty for balancing while strengthening the muscles required for dynamic stabilization

The Fitter is useful for weight shifting

• Plyometrics begin with low-impact hopping, progressing to double-leg bounding, and finally single-leg hopping.

References

Prentice, W.E. (2004). Rehabilitation Techniques for Sports Medicine and Athletic Training, 4th ed., McGraw-Hill

Houglum, P.A. (2005). Therapeutic Exercise for Musculoskeletal Injuries, 2nd ed., Human Kinetics.

Kisner, C. & Colby, L. (2002). Therapeutic Exercise Foundations & Techniques, 4th ed., F.A. Davis.

http://www.google.com - Images