Ch7 Regaining Postural Stability And Balance

Balance is critical in dictating movement strategies within the closed kinetic chain. In a closed kinetic chain, the distal segment of the chain is fixed and the proximal segment moves. This means that the movement and stability of the entire chain are dependent on the balance and coordination of the body. In order to maintain balance and execute effective movement strategies, the body must rely on the stability and control provided by the closed kinetic chain.

The position of the body in relation to gravity and its surroundings is sensed by combining visual, vestibular, and somatosensory inputs. Visual input refers to the information received from the eyes about the body's position in space. Vestibular input comes from the inner ear and helps in detecting changes in head position and movement. Somatosensory input involves the sensory receptors in the skin, muscles, and joints, which provide information about body position and movement. By combining these three inputs, the body is able to accurately perceive its position in space.

Classification of Balance Exercises
Static
-CoG is maintained over a fixed base of support, on a stable surface

Semi-dynamic
-Person maintains CoG over a fixed base of support while on a moving surface
-Person transfers CoG over a fixed base of support to selected ranges and or directions within the LOS, while on a stable surface

Dynamic
-Maintenance of CoG within LOS over a moving base of support while on a stable surface (involve stepping strategy

Functional
-Same as dynamic with inclusion of sports specific task

Classification of Balance Exercises
Static
-CoG is maintained over a fixed base of support, on a stable surface

Semi-dynamic
-Person maintains CoG over a fixed base of support while on a moving surface
-Person transfers CoG over a fixed base of support to selected ranges and or directions within the LOS, while on a stable surface

Dynamic
-Maintenance of CoG within LOS over a moving base of support while on a stable surface (involve stepping strategy

Functional
-Same as dynamic with inclusion of sports specific task

Classification of Balance Exercises
Static
-CoG is maintained over a fixed base of support, on a stable surface

Semi-dynamic
-Person maintains CoG over a fixed base of support while on a moving surface
-Person transfers CoG over a fixed base of support to selected ranges and or directions within the LOS, while on a stable surface

Dynamic
-Maintenance of CoG within LOS over a moving base of support while on a stable surface (involve stepping strategy

Functional
-Same as dynamic with inclusion of sports specific task

Balance movements involve motions of the ankle, knee, and hip joints. These joints work together in a coordinated manner to maintain balance and stability. The ankle joint allows for movements such as dorsiflexion and plantarflexion, which help in maintaining balance. The knee joint provides stability and allows for flexion and extension movements. The hip joint plays a crucial role in balance by allowing movements such as hip flexion, extension, abduction, and adduction. Therefore, all three joints are essential for maintaining balance and are controlled by coordinated actions along the kinetic chain.

CNS involvement

Sensory organization
-Determines timing, direction and amplitude of correction based on input
-System relies on one sense at a time for orientation
-For adults the somatosensory system is relied on primarily

Muscle coordination
-Collection of processes that determine temporal sequencing and distribution of contractile activity

Steadiness
-Ability to keep body as motionless as possible
-Measure of postural sway

Symmetry
-Ability to distribute weight evenly between 2 feet in upright stance
-Measures center of pressure, center of balance and center of force

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

Utilization of external perturbation
-Some are systematic (sinusoidal) while others are unpredictable and determined via changes in subject sway

Center of Pressure (CoP)
-Center of the distribution of the total force applied to the supporting surface
-Calculated from horizontal moment and vertical force data through a triaxial force platform

Center of Balance (CoB)
-Point between feet where the ball and heel of each foot has 25% of the body weight (Chattecx Balance System)
-Relative weight positioning

Center of Vertical Force (CoF)
-Center of vertical force exerted by the feet against the support surface (Neurocom’s Equitest)

Steadiness
-Ability to keep body as motionless as possible
-Measure of postural sway

Symmetry
-Ability to distribute weight evenly between 2 feet in upright stance
-Measures center of pressure, center of balance and center of force

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

Utilization of external perturbation
-Some are systematic (sinusoidal) while others are unpredictable and determined via changes in subject sway

Center of Pressure (CoP)
-Center of the distribution of the total force applied to the supporting surface
-Calculated from horizontal moment and vertical force data through a triaxial force platform

Center of Balance (CoB)
-Point between feet where the ball and heel of each foot has 25% of the body weight (Chattecx Balance System)
-Relative weight positioning

Center of Vertical Force (CoF)
-Center of vertical force exerted by the feet against the support surface (Neurocom’s Equitest)

Steadiness
-Ability to keep body as motionless as possible
-Measure of postural sway

Symmetry
-Ability to distribute weight evenly between 2 feet in upright stance
-Measures center of pressure, center of balance and center of force

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

Utilization of external perturbation
-Some are systematic (sinusoidal) while others are unpredictable and determined via changes in subject sway

Center of Pressure (CoP)
-Center of the distribution of the total force applied to the supporting surface
-Calculated from horizontal moment and vertical force data through a triaxial force platform

Center of Balance (CoB)
-Point between feet where the ball and heel of each foot has 25% of the body weight (Chattecx Balance System)
-Relative weight positioning

Center of Vertical Force (CoF)
-Center of vertical force exerted by the feet against the support surface (Neurocom’s Equitest)

Steadiness
-Ability to keep body as motionless as possible
-Measure of postural sway

Symmetry
-Ability to distribute weight evenly between 2 feet in upright stance
-Measures center of pressure, center of balance and center of force

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

Utilization of external perturbation
-Some are systematic (sinusoidal) while others are unpredictable and determined via changes in subject sway

Center of Pressure (CoP)
-Center of the distribution of the total force applied to the supporting surface
-Calculated from horizontal moment and vertical force data through a triaxial force platform

Center of Balance (CoB)
-Point between feet where the ball and heel of each foot has 25% of the body weight (Chattecx Balance System)
-Relative weight positioning

Center of Vertical Force (CoF)
-Center of vertical force exerted by the feet against the support surface (Neurocom’s Equitest)

Classification of Balance Exercises
Static
-CoG is maintained over a fixed base of support, on a stable surface

Semi-dynamic
-Person maintains CoG over a fixed base of support while on a moving surface
-Person transfers CoG over a fixed base of support to selected ranges and or directions within the LOS, while on a stable surface

Dynamic
-Maintenance of CoG within LOS over a moving base of support while on a stable surface (involve stepping strategy

Functional
-Same as dynamic with inclusion of sports specific task

Steadiness
-Ability to keep body as motionless as possible
-Measure of postural sway

Symmetry
-Ability to distribute weight evenly between 2 feet in upright stance
-Measures center of pressure, center of balance and center of force

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

Utilization of external perturbation
-Some are systematic (sinusoidal) while others are unpredictable and determined via changes in subject sway

Center of Pressure (CoP)
-Center of the distribution of the total force applied to the supporting surface
-Calculated from horizontal moment and vertical force data through a triaxial force platform

Center of Balance (CoB)
-Point between feet where the ball and heel of each foot has 25% of the body weight (Chattecx Balance System)
-Relative weight positioning

Center of Vertical Force (CoF)
-Center of vertical force exerted by the feet against the support surface (Neurocom’s Equitest)

Phase I
-Non-ballistic types of drills
-Static balance training
-Bilateral to unilateral on both involved and uninvolved sides
-Utilize multiple surfaces to safely challenge athlete and maintaining motivation
-With and without arms/counterbalance
-Eyes open and closed
-Alterations in various sensory information
-ATC can add perturbations
-Incorporation of multiaxial devices
-Train reflex stabilization and postural orientation

Phase II
-Transition from static to dynamic
-Running, 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 transition
--Involve displacement or perturbation of CoG
--Bilateral, unilateral stances or weight transfers involved
--Sit-stand exercises, focus on postural

Phase III
-Dynamic and functional types of exercise
-Slow to fast, low to high force, controlled to uncontrolled
-Dependent on sport athlete is involved in
-Start with bilateral jumping drills – straight plane jumping patterns
-Advance to diagonal jumping patterns
--Increase length and sequences of patterns
-Progress to unilateral drills
--Pain and fatigue should not be much of a factor
-Can also add a vertical component to the drills
-Addition of implements
--Tubing, foam roll,
-Final step = functional activity with subconscious dynamic control/balance

Sensory Input

Somatosensory
-Provides information concerning relative position of body parts to support surface and each other

Vision
-Measures orientation of eyes and head in relation to surrounding objects
-Role in maintenance of balance

Vestibular
-Provides information dealing with gravitational, linear and angular accelerations of the head with respect to inertial space
-Minor role when visual and somatosensory systems are operating correctly

Sensory Input

Somatosensory
-Provides information concerning relative position of body parts to support surface and each other

Vision
-Measures orientation of eyes and head in relation to surrounding objects
-Role in maintenance of balance

Vestibular
-Provides information dealing with gravitational, linear and angular accelerations of the head with respect to inertial space
-Minor role when visual and somatosensory systems are operating correctly

Phase I
-Non-ballistic types of drills
-Static balance training
-Bilateral to unilateral on both involved and uninvolved sides
-Utilize multiple surfaces to safely challenge athlete and maintaining motivation
-With and without arms/counterbalance
-Eyes open and closed
-Alterations in various sensory information
-ATC can add perturbations
-Incorporation of multiaxial devices
-Train reflex stabilization and postural orientation

Phase II
-Transition from static to dynamic
-Running, 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 transition
--Involve displacement or perturbation of CoG
--Bilateral, unilateral stances or weight transfers involved
--Sit-stand exercises, focus on postural

Phase III
-Dynamic and functional types of exercise
-Slow to fast, low to high force, controlled to uncontrolled
-Dependent on sport athlete is involved in
-Start with bilateral jumping drills – straight plane jumping patterns
-Advance to diagonal jumping patterns
--Increase length and sequences of patterns
-Progress to unilateral drills
--Pain and fatigue should not be much of a factor
-Can also add a vertical component to the drills
-Addition of implements
--Tubing, foam roll,
-Final step = functional activity with subconscious dynamic control/balance

Ankle Strategy
-Shifts CoG by maintaining feet and rotating body at a rigid mass about the ankle joints
--Gastrocnemius or tibialis anterior are responsible for torque production about ankle
--Anterior/posterior sway is counteracted by gastrocnemius and tibialis anterior, respectively
-Effective for slow CoG movements when base of support is firm and within LOS
-Also effective when CoG is offset from center

Hip Strategy
-Relied upon more heavily when somatosensory loss occurs and forward/backward perturbations are imposed or support surface lengths are altered
-Aids in control of motion through initiation of large and rapid motions at the hip with anti-phase rotation of ankle
-Effective when CoG is near LOS perimeter and when LOS boundaries are contracted by narrower base of support

Ankle Strategy
-Shifts CoG by maintaining feet and rotating body at a rigid mass about the ankle joints
--Gastrocnemius or tibialis anterior are responsible for torque production about ankle
--Anterior/posterior sway is counteracted by gastrocnemius and tibialis anterior, respectively
-Effective for slow CoG movements when base of support is firm and within LOS
-Also effective when CoG is offset from center

Hip Strategy
-Relied upon more heavily when somatosensory loss occurs and forward/backward perturbations are imposed or support surface lengths are altered
-Aids in control of motion through initiation of large and rapid motions at the hip with anti-phase rotation of ankle
-Effective when CoG is near LOS perimeter and when LOS boundaries are contracted by narrower base of support

Balance Error Scoring System (BESS)
-Utilizes three stances
--Double, single, tandem on both firm and foam surfaces
-Athletes are instructed to remain motionless with hands on hips for 20 seconds
-Unnecessary movements and correction of body position are counted as ‘errors’ (max score = 10)
-Results are best utilized if compared to baseline data

Semi-dynamic and dynamic tests
-functional reach tests
-timed agility tests
-carioca
-hop test
-Bass test for dynamic balance
-Timed T-band kicks
-Timed balance beam walks (eyes open and closed)
--While criticized for merely reporting time of posture maintenance, angular displacement or distance covered – test can provide valuable information about function and return to play capability

Steadiness
-Ability to keep body as motionless as possible
-Measure of postural sway

Symmetry
-Ability to distribute weight evenly between 2 feet in upright stance
-Measures center of pressure, center of balance and center of force

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

Utilization of external perturbation
-Some are systematic (sinusoidal) while others are unpredictable and determined via changes in subject sway

Center of Pressure (CoP)
-Center of the distribution of the total force applied to the supporting surface
-Calculated from horizontal moment and vertical force data through a triaxial force platform

Center of Balance (CoB)
-Point between feet where the ball and heel of each foot has 25% of the body weight (Chattecx Balance System)
-Relative weight positioning

Center of Vertical Force (CoF)
-Center of vertical force exerted by the feet against the support surface (Neurocom’s Equitest)

Phase I
-Non-ballistic types of drills
-Static balance training
-Bilateral to unilateral on both involved and uninvolved sides
-Utilize multiple surfaces to safely challenge athlete and maintaining motivation
-With and without arms/counterbalance
-Eyes open and closed
-Alterations in various sensory information
-ATC can add perturbations
-Incorporation of multiaxial devices
-Train reflex stabilization and postural orientation

Phase II
-Transition from static to dynamic
-Running, 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 transition
--Involve displacement or perturbation of CoG
--Bilateral, unilateral stances or weight transfers involved
--Sit-stand exercises, focus on postural

Phase III
-Dynamic and functional types of exercise
-Slow to fast, low to high force, controlled to uncontrolled
-Dependent on sport athlete is involved in
-Start with bilateral jumping drills – straight plane jumping patterns
-Advance to diagonal jumping patterns
--Increase length and sequences of patterns
-Progress to unilateral drills
--Pain and fatigue should not be much of a factor
-Can also add a vertical component to the drills
-Addition of implements
--Tubing, foam roll,
-Final step = functional activity with subconscious dynamic control/balance

CNS involvement

Sensory organization
-Determines timing, direction and amplitude of correction based on input
-System relies on one sense at a time for orientation
-For adults the somatosensory system is relied on primarily

Muscle coordination
-Collection of processes that determine temporal sequencing and distribution of contractile activity

Steadiness
-Ability to keep body as motionless as possible
-Measure of postural sway

Symmetry
-Ability to distribute weight evenly between 2 feet in upright stance
-Measures center of pressure, center of balance and center of force

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

Utilization of external perturbation
-Some are systematic (sinusoidal) while others are unpredictable and determined via changes in subject sway

Center of Pressure (CoP)
-Center of the distribution of the total force applied to the supporting surface
-Calculated from horizontal moment and vertical force data through a triaxial force platform

Center of Balance (CoB)
-Point between feet where the ball and heel of each foot has 25% of the body weight (Chattecx Balance System)
-Relative weight positioning

Center of Vertical Force (CoF)
-Center of vertical force exerted by the feet against the support surface (Neurocom’s Equitest)

Sensory Input

Somatosensory
-Provides information concerning relative position of body parts to support surface and each other

Vision
-Measures orientation of eyes and head in relation to surrounding objects
-Role in maintenance of balance

Vestibular
-Provides information dealing with gravitational, linear and angular accelerations of the head with respect to inertial space
-Minor role when visual and somatosensory systems are operating correctly