Unit 3 Week 10 Flashcards
the ability to control the center of mass in relationship to the base of support
postural stability
a point that is at the center of the of the total body mass, which is determined by finding the weighted average of the COM of each body segment
center of mass
vertical projection of the COM
center of gravity
the area of the body that is in contact with the support surface
base of support
what are the 3 domains that influence postural control?
individual: motor, sensory, cognitive
environment: support surfaces, sensory context, cognitive load
task: steady-state, reactive, proactive
what are the 3 domains under individual that influence postural control?
motor: responsible for executing all movements and maintaining postural control
sensory: helps perceive our body’s position, movement, and environment
cognitive: conscious control of movement allocating attention, making predictions, and facilitating adaptations to different tasks and environments
what is steady-state in relation to a task?
ability to maintain balance during static postures (standing still, sitting)
what is reactive in relation to a task?
compensatory adjustments we make in response to unexpected events
what control mechanism does a reactive task use?
feedback control mechanism: the process of adjusting body movements on sensory feedback
what is proactive in relation to a task?
anticipatory adjustments made before a potentially destabilizing event occurs
relies heavily on previous experiences and learned motor patterns to predict what sensory input or motor responses will be needed for that action
what control mechanism does a proactive task use?
feed forward control mechanism: adjustments are made in anticipation of movement or change in balance
what are the age-related changes in motor systems related to postural control?
slowed reaction time - affects balance
decreased muscle strength (and endurance) - affects balance
impaired coordination and flexibility - impacts movement efficiency
altered postural strategy selection
how do balance strategies differ in older adults compared to younger individuals?
may rely more heavily on hip strategies instead of ankle strategies - not able to defend against smaller balance disturbances
what are the age-related changes in steady state balance related to postural control?
increased postural sway
altered weight distribution
reduced stability limits
how does weight distribution change with aging?
older adults tend to shift weight more towards their heels
what are the age-related changes in reactive balance control related to postural control?
delayed reaction times
altered compensatory step strategies
reduced muscle power
what are the age-related changes in anticipatory balance control related to postural control?
reduced anticipatory adjustments
impaired sensory integration
diminished cognitive processing
what are the age-related changes in individual sensory systems related to postural control?
decline in visual function (visual acuity, depth perception, and contrast sensitivity)
vestibular system changes
proprioceptive system degradation
what are the age-related changes in cognitive issues related to postural control?
reduced attentional resources (affects ability to monitor and adjust postural control)
slower processing speed
impaired dual-task performance (cognitive task while balancing)
where in the ICF framework does mobility fit?
activity impairments but affects participation
the ability to initiate and maintain movement, including the coordinated actions of muscle groups to produce forward motion
progression
the ability to maintain balance during movement, including using visual, vestibular, and proprioceptive inputs to adjust body position
postural control
the ability to adjust gait patterns in response to changing environmental demands and unexpected obstacles
adaptation
what is stead-state gait?
consistent, uninterrupted walking over a flat surface at a constant speed
what are the key features of a stead-state gait?
regular, rhythmic stepping patterns, symmetrical strides, and consistent foot placement
what role does steady-state gait play in postural control?
provides a foundation for understanding more complex gait tasks and forms a baseline for identifying gait abnormalities
what is kinematics?
the study of motion without considering the forces that cause it
what are the key features of kinematics during steady-state gait?
stride length, cadence, walking speed, joint angles (hip, knee, ankle), and gait phases (stance and swing)
what is stride length?
the distance covered from the point of initial contact of one foot to the next initial contact of that same foot
what is cadence?
of steps per minute
what is walking speed?
stride length x cadence = meters per second
what is progression in reference to muscle activation patterns in steady-state gait?
involves a coordinated sequence of muscle activation to produce smooth movement, typically involving the hip flexors, knee extensors, and ankle plantarflexors
what postural control occurs during muscle activation patterns in steady-state gait?
continuous adjustments of muscle activation to maintain balance, typically involving the trunk and lower limb muscles
in what phase of gait is the foot in contact with the ground? and what percent of cycle?
stance (60%)
what are the 3 parts of stance phase?
heel strike, midstance, and toe-off
what is occurring during heel strike?
foot initially contacts the ground
quads and tibialis anterior control knee flexion and prevent foot slap, hip extensors (glute max) control forward motion of the trunk
what is occurring during midstance?
body’s weight is directly over the foot
quads activate to maintain knee extension and hip extensors keep trunk upright, plantar flexors (soleus) control forward motion of the tibia over the foot
what is occurring during toe-off?
plantar flexors are most active pushing off the ground to propel the body forward and initiate the swing phase of gait
in what phase of gait is the foot off the ground, swinging forward from toe-off to heel strike? percent of gait cycle?
swing phase; 40%
what are the 3 parts of the swing phase of gait?
initial swing, mid-swing, and terminal swing
what is occurring during initial swing?
right after toe off
hip flexors (iliopsoas) and knee flexors (hamstrings) are active moving the thigh forward and lifting the foot off the ground
what is occurring during mid-swing?
continued hip flexion and beginning of knee extension
quads contract to prevent excessive knee flexion and prepare the leg for landing
what is occurring during terminal swing?
hip extends and knee continues to extend in preparation for heel strike, tibialis anterior contracts to dorsiflex the ankle preparing the foot for initial contact
what are the key muscle groups involved in the swing phase of gait?
hip flexors, knee flexions, and ankle dorsiflexors
a rapid and automatic response that helps maintain stability when unexpected disturbances occur
reactive balance control
what role does reactive balance control play in gait?
allows for rapid adjustments to maintain stability during walking, such as when encountering unexpected slippery patches or obstacles
the ability to anticipate changes in the environment or task, adjusting the gait pattern in advance to minimize instability
proactive balance control
what role does proactive balance control play in gait?
involves making adjustments to gait pattern before stepping onto uneven ground or altering foot placement to navigate obstacles
what are the key components of initiating gait?
weight shifting
balance adjustments
muscle activation
what weight shift needs to occur when initiating gait?
shifting the body’s COM from a stable base to the stand leg
what muscle activation needs to occur to initiate the gait cycle?
hip flexors, quadriceps, and calf muscles to propel the body forward and achieve the first step
what are the key sensory systems involved in gait?
visual, vestibular, and proprioceptive
how is the visual system used during gait?
provides information about the environment, including obstacles, surfaces, and depth perception
how is the vestibular system used during gait?
detects head movements and contributes to spatial orientation and balance
how is the proprioceptive system used during gait?
provides information about body position, limb movement, and muscle tension
how do sensory systems contribute to gait stability?
allows for precise control of gait, maintaining stability, adapting to changes, and avoiding falls.
what are the key cognitive systems involves in gait?
attention, executive function, and memory
how do impairments in cognitive function affect gait performance?
can affect gait stability, speed and adaptability and increase the risk of falls
the ability to simultaneously perform two tasks, such as walking, while performing a secondary cognitive or motor task
dual-task performance
what challenges may an older adult have with dual-tasking during gait?
dividing attention between gait and a secondary task can lead to changes in gait parameters, reduced gait stability, and increase fall risk
what impact can dual-task interference have on gait?
can affect gait speed, step length, stride time, and overall gait quality
what strategies can be used to improve dual-task performance?
training, practice, and interventions focusing on attentional strategies, task prioritization, and cognitive-motor integration can enhance dual-task performance during gait
what are the 3 requirements of successful negation of stairs?
the generation of primarily concentric forces to propel the body upstairs or eccentric forces to control the body’s decent downstairs
controlling the COM within a constantly changing BOS
the capacity to adapt strategies used for progression and stability to accommodate changes in their stair environment (height, width, railings)
what muscle activation occurs during ascent of stairs?
primarily concentric forces by quads and glutes to lift body upwards and forwards
what muscle activation occurs during descent of stairs?
eccentric forces to control and slow down the rate of descent providing stability and reducing impact on the joint
what are the 3 components of the stance phase during ascent of stairs?
weight acceptance, pull-up, and forward continuance
what are the 2 components of the swing phase during ascent of stairs?
foot clearance and foot placement
what are the 3 components of the stance phase during descent of stairs?
weight acceptance, forward continuance, and controlled lowering
what are the 2 components of the swing phase during descent of stairs?
leg pull-through and preparation for foot placement
what are the key characteristics of a sit-to-stand?
weight shift, LE muscle activation, trunk and core stability, balance and postural control, and smooth movement execution
what factors influence sit-to-stand performance?
muscle strength and power, joint mobility and flexibility, postural control and balance, and functional capacity and endurance
what are the 4 phases of the sit-to-stand?
preparation, weight transfer, rising, and stabilization
what are the key characteristics of a supine-to-sit transfer?
core activation, trunk flexion and UE use, LE coordination, balance and control, smooth and controlled movement
what factors influence supine-to-sit performance?
muscle strength and endurance, joint ROM, body awareness and proprioception, and environmental factors
what age related changes occur in steady-state gait?
decreased gait speed, reduced stride length, increased double support time, altered temporal parameters, decreased arm swing
what age related changes occur in reactive balance?
slower reactive responses, reduced step length and magnitude, impaired recovery
what age related changes occur in proactive balance?
reduced proactive adjustments, altered step width and speed, decreased gait adaptability
what strategies can be used to enhance adaptive gait in older adults?
balance and strength training, environmental modifications, assistive devices, multisensory training
what are the age-related changes in gait initiation?
reduced forward propulsion, delayed weight shift, slower limb movement, and increased postural sway during gait initiation
what are the age-related changes in backwards gait?
reduced gait speed, altered step length, increased postural sway, and decreased stability during backward walking
