Symposium - Gait and posture Flashcards
what is gait
it is translocates centre of body mass in the direction of locomotion
what does normal gait relies on?
Joint - intact bones and well functioning joints,
muscle - adequate muscle strength
nerves - relies on both CNS & PNS
Vision
also relies on vestibular and auditory systems
why does the gait changes in elderly?
decrease muscle size, decrease strength and flexibility
what are the major changes of the gait in elderly
reduction in overall velocity, reduction in the step/stride length - generally velocity is preserved by taking more steps instead of increasing stride
where is the centre of gravity lie in the body
lies anterior to S2 vertebra, slightly posterior to hip joints, anterior to knee and ankle joints
what is the most stable position for hips and knees
extension - minimises need for muscular contraction during standing
what is forward sway
due to the centre of gravity being anterior to the ankle joint, the natural movement is to fall forward
how is forward sway counteracted?
counteracted by contraction of plantar flexor muscles
what are the 2 phrases of the walking cycles?
stance phase (foot in contact with ground;60%), swing phrase (foots in the air;40%)
what are the sequences of the walking cycles
heel strike (initial contact)- loading response (foot flat) - midstance - terminal stance (heel off) - preswing (toe off) - initial & mid swing - terminal swing
what is double & single support in the gait cycle
double support = both feet on the ground
what are the 5 sequences in the stance phase
heel strike - loading response - mid-stance-terminal stance- pre-swing
what are the 3 sequences within the swing phase
initial swing - mid-swing - terminal swing
what is dynamic contraction
it is muscle contracts with a change in length
what is isometric contraction?
it is muscles contracts without changing in length
what controls the lowering of forefoot to the ground
eccentric contraction of tibialis anterior
what is eccentric contraction
lengthening of muscles
what is concentric contraction
muscle shortens while contracting
how is deceleration of forward momentum achieved
hip extension by gluteus maximus
when does the stance phase starts ?
when the heel strikes ground
what preserve the longitudinal arch of foot?
the intrinsic muscle of the foot
when does the loading response start?
when the foot comes into full contact with ground
what is require to prevent knee buckling under weight
knee extension - by quadriceps femoris
when does mid-stance begin
it starts when the opposite limb swings past the stance limb
what is required to stabilise the pelvis during mid-stance phase
abduction of hip is required to stabilise the hip
how is stabilisation of the hip achieve during the mid-stance?
contraction of gluteus medius, gluteus minimus and tensor fasia lata
when does terminal stance start
it is when the heel starts to lift off ground
how is the lift off motion achieved?
it is achieved by plantar flexion
what take place in the pre-swing phase?
plantar flexion of digits in order to push off ground and accelerate mass forward
what is important for toe off ?
hallux (the big toe) ie stabilisation of the hallux is important
what is apropulsive gait
it is weak push off
what will apropulsive gait cause?
it will cause shorter stride length & decreased gait velocity
what carries limb forward in the initial & swing phase
hip flexion - iliopsoas and rectus fermoris
what happens in the initial & mid-swing phase?
hip flexion, toes & foot dorsiflexed (allow foot to clear the ground), knee flexion (to shorten limb), contralateral abductors of hip, neck rotates to keep face pointing forward
what is the angle for knee flexion to shorten the limb
65 degree
what happens in the terminal swing
knee flexion changes to extension to place foot for heel strike - quadriceps
dorsiflexion of ankle - tibialis anterior
deceleration of the limb - by eccentric contraction of hamstring
why does limb circumduct for the swinging part of the gait cycle
it is because limited knee flexion means limb can not be shortened & swinging leg moves in an arc rather than straight-forwards
what happens foot can not be doriflexed
footdrop - likely damages to common fibular nerve
why does the centre of gravity remains almost constant during walking?
rotation of the pelvis allow the reduction of the vertical drop - stance limn = internal rotate pelvis, swing limb = external rotation of the pelvis
how else is the pelvis moved to minimise rise in centre of gravity
pelvis drop to swing side
what minimise the lateral shift of centre of gravity?
hip adduction
