MC Posture and Balance Flashcards
Balance – definition
The ability to control one’s center of mass (COM) with respect to the base of support (BOS).
Base of Support (BOS)
BOS is the area of the body in contact with the support surface
Postural Stability = Balance
Balance is the ability to keep the vertical projection of the center of mass (COM) within the limits of base of support
Center of Pressure (COP)
- COP is the center of the distribution of total forces applied to the support surface
- COP represents the average “location” of these forces. It is a point on a 2-D plane!
Stability Limits or “cone of stability”
Stability limits refer to the boundaries within which the body can maintain stability without changing the base of support.
Balance: Commonly described subjectively…
- Zero: unable to maintain balance or no attempt made
- Poor: able to balance with or without UE support for 5 seconds or less
- Fair: able to balance with or without UE support from 15 - 60 seconds and/or able to hold against slight resistance
- Good: able to hold balance against moderate resistance
4 Types of Balance
Static
Dynamic
Protective
Functional
Static Balance (Time)
- time as objective measure
- maintain position over time
Static Balance (resistance)
- resistance is the objective measure
- maintain position against manual resistance measured using HHD
Static Balance (AFF)
- Anticipatory, feed-forward
- Reach in various directions within arm’s length
Dynamic Balance (RFB)
- Reactive, Feedback
- Manually displace COM toward the edges of the BOS to elicit the equilibrium reactions
Dynamic Balance (AFF)
- Anticipatory, Feed-forward
- Reach in various directions beyond arm’s length to elicit trunk and arm balance reactions
Protective Reactions
- Reactive, feedback
- Slow/quick displacement of the COM outside the BOS to elicit a change in BOS (arm and/or leg movement)
Functional Balance
- Anticipatory, feed-forward and reactive feedback
- Utilization of effective balance strategies while performing a set of functional tasks which progress in difficulty
Balance(T)
- Time is the objective measure
- BalanceT is frequently tested in sitting and standing
- However, balance can be tested in any of the developmental positions
Static BalanceT - Time
Maintain a position over time
Static BalanceR - Resistance [Subjective Assessment]
- Attempt to assume near-normal posture with/without BUE support
- -sit, stand, developmental positions
- Maintain the position against gradual, matched manual resistance (“min, mod, max”)
- -Co-contraction-rhythmic stabilization
- -Tonic holding-alternating isometrics
- Verbal cue: “hhhhoooolllllddd”
Static BalanceR - Resistance [Objective Assessment]
- Objectively measured using a hand-held dynamometer
- Published as Sitting Strength
- -Procedures for sitting strength written in details i
MicroFet2 - Hand-Held Dynamometer
- measures peak force (pounds)
- Low threshold – 0.8–150 lbs. (0.1 lb. increments)
- High threshold – 3–150 lbs. (1.0 lb. Increments)
Static Balance Basic Procedures Patient Position - Sitting
- Sitting on a height-adjustable table
- Feet flat on the floor
- Hips and knees at 90 dg
- Maximize thigh contact on support surface - stable BOS
- UE unsupported or supported
- -Supported – using bilateral upper extremities for support
- -Unsupported – hands not in contact with the support surface
Static Balance Basic Procedures: PT force application
-Anterior – mid-sternum
-Posterior – mid-upper back between scapula
-Right and left lateral – acromion
Instructions “hold, do not let me move you” or “push as hard as you can”
-Gradual build up of force (over 3-4 seconds) and gradual release of force (over 3-4 seconds)
-Stop test when displace the subject approximately 1 inch (break test)
-2 practice trials and 3 actual trials (mean of actual trials)
Sitting Strength (Static Balance) Test – Intra-Rater Reliability
Unsupported: Intra-class Correlation Coefficients (ICCs) = 0.80 – 0.98
BUE Supported:
ICCs = 0.83 – 0.99
Sitting Strength (Static Balance) Test – Inter-Rater Reliability
Unsupported:
ICCs = 0.93 – 0.98
BUE Supported:
ICCs = 0.95 – 0.99
Static Balance AFF -Anticipatory, feed-forward
- Reach in various directions within arm’s length (goal = stability)
- Patient is anticipating what muscle actions or motor control is necessary to prevent falling due to the progressive weight of the arm
- Biomechanics of weight of arm (COM of arm relative to distance from axis of rotation)
Dynamic Balance RFB - Reactive, feedback
- Manually displace the COM toward the edges of the BOS to elicit the equilibrium or balance reactions
- Reactive, Feedback balance = Patient is responding to therapist manual perturbations (stimulus > response = feedback)
Sitting Equilibrium Reactions
- Lateral right displacement or perturbation
- Lateral left displacement or perturbation
- Anterior displacement or perturbation
- Posterior displacement or perturbation
Standing Equilibrium Reactions
- Lateral right displacement or perturbation
- Lateral left displacement or perturbation
- Anterior displacement or perturbation
- Posterior displacement or perturbation
Dynamic BalanceAFF - Anticipatory, feed-forward
- Reach in various directions beyond arm’s length to elicit trunk and arm (sitting) and whole body (standing) balance reactions
- Pt is anticipating what muscle actions or motor control is necessary to prevent falling due to the progressive weight of the arm
- Know AFF actions of the trunk and legs in sitting and in standing
Multi-Directional Reach test (MDRT)
Objective measure of dynamic sitting and standing AFF balance
“reach as far as possible;
you must return to upright
independently”
MDRT Procedures - Sitting
- Equipment - metal meter stick, rolling chair with out arm rests (preferably brakes), clear clipboard
- Begin in an erect sitting posture, feet flat on floor, arm near wall (not touching), hand in a fist, shoulder raised to 90° flexion
- Meter stick placed at acromion height
- Initialreading taken using the 3rd PIP joint of fisted hand
- “Reach as far as you can in the (appropriate-forward, diagonal, sideways) direction; you must return to upright independently.”
- 3 trials are recorded in the anterior, right lateral, right diagonal, left lateral, and left diagonal directions.
Dynamic Balance – Protective Reactions
- Protective reactions - Reactive, feedback balance
- PT manual perturbations to elicit patient change in BOS to accommodate COM beyond BOS
- 1st Slow perturbations to just beyond BOS or “edge of cone of stability”
- -Sitting arm movements
- -Standing leg movements – step and cross-overs
- 2nd, relatively faster perturbations (yet safe)
Functional Balance
- Utilization of effective balance strategies while performing a set of functional tasks which progress in difficulty
- Example Outcome Measures
- -Berg Functional Balance scale
- -Tinetti balance scale
- -Mini-BEST test
