week 13-2 Flashcards
infants have a strong reliance on vision to control their balance
true
_____ synergy- particular muscles work together to achieve the task; in case of reactive balance occurs without voluntary control
muscle
somatosensory/ proprioception
reduced sensory feedback from legs and feet increased postural sway
vestibular
head titling
COP RMS increases with head tilt even when visual input remains constant
blind individuals
blind participants had smaller COP- COM displacement compared to sighted with eyes closed
- if a deficit in postural control due to a loss of vision remained it should stay the same
vestibular loss patients
immediately after a unilateral/ bilateral loss of vestibular info, patients adopt abnormal alignment and increase in sway
-patients rapidly adapt to the loss of vestibular info
-after the initial recovery period, postural sway with eyes open is often similar to that observed in controls
locomotion definition
a controlled rhymic act of moving the body from one place to another
- involves repeated cycles of movements
-CNS processing and transformation into appropriate motor output
- sensory contribution form visual, proprioceptive, vestibular and cutaneous source
stance
starts with heel contact (60% of step cycle)
swings
starts with toe- off 40%
walking
- locomotion in which the legs move in antiphase
-one foot or the other is in contact with ground at all time - includes a short period of time when both feet are on ground at same time
- plantigrade-place whole sole of foot on ground
running
- locomotion in which the legs move in antiphase
-both feet are never on the ground at the same time - includes period when both feet off ground (flight period)
- plantigrade (slow jogging)
heel contact in knee extension
absorb impact- eccentrically contract
heel contact ankle dorsiflexor
decelerate eccentrically contract
toe-off propulsion forward
concenter contraction pf plantar flexors
Swing - forward acceleration of thigh
concentric contraction of quadriceps
Swing - toe clearance
concentric
contraction of dorsiflexors
Swing - forward deceleration
eccentric contraction of hamstrings
Knee Flexors
Knee Extensors
Plantar Flexors
Dorsiflexors
LOCOMOTION - WALKING
Neural control of gait: 3) Swing
Sensory feedback is important for
- Initiating walking
- Controlling phase transitions (e.g. from stance to swing phase)
- Regulating level of muscle activity
- Correcting for unexpected disturbances (e.g., stumbling-corrective response)
controlling phase and timing of transitions
Making transition from stance to swing during walking
Stretch hip flexors (muscle spindles)
Inhibit knee extensor and cause earlier onset of knee flexor
Muscle receptors in hip flexor signal when swing phase should be initiated
stumbling corrective response
-encounter obstacle during swing phase
-automatic flexion response to step over the obstacle
