Gait Flashcards
What is Gait
- A method of human locomotion.
- A learned feature.
- Automatic and conscious control – Central Pattern Generators (sit in spinal cord)
- Involves use of both legs alternately for support and propulsion.
- Walking ↔ Gait but Gait implies manner or style.
- Varies according to age: gender: body geometry and pathology
State tasks of gait cycle
Three main tasks must be accomplished:
- Weight acceptance – transfer of weight onto limb that has completed swing and has unstable alignment. Shock absorption & forward progression.
a. CVA pts particularly struggle with this - Single limb support – one limb must support the entire body weight and provide truncal stability.
- Limb advancement – requires foot clearance as limb swings through to its destination in front of body.
State phases of gait cycle
Stance phase - 60% of gait cycle. Considered leg has a period in contact with ground
Swing phase - 40% of cycle. Ave speed
Period when foot is not in contact with the ground.
Initial swing = 60-75%
Mid swing = 75-85%
Terminal swing = 85-100%
Explain initial contact (heel strike)
First period of double stance
When foot touches ground; other leg at end of terminal stance
Muscle activity in initial contact
Hip flexed – extension initiated =
hamstrings
Knee extended - Quadriceps, hamstrings (eccentric)
Ankle dorsiflexed - Tib ant
Eccentric lowering of foot to floor
Explain loading response (flat foot)
Double support ends
Body weight transferred onto stance leg; other leg in pre-swing phase
Muscle activity loading response (flat foot)
Hip Ext- concentric hamstrings, glute max; contralateral ABDs stabilise pelvis & trunk
Knee Flex (a cushion effect) - eccentric Quadriceps
Ankle - PF by eccentric of dorsiflexors; eversion (supination) – transfers wt to lateral border of foot
Explain mid-stance
First part of single limb support
COM (COG) passes from behind to in front of stance foot
Begins with lifting foot and continues until body weight is over supporting foot: stance leg goes over foot; other leg is in mid-swing
Muscle activity of mid-stance
Hip extension - momentum; Abductors of stance limb control contralateral pelvis dropping
Knee restores to slight flex - more ext; not much mvt
Ankle - DF by momentum, controlled eccentrically by PFs
Explain terminal stance
Body is propelled forwards and starts to end stance phase
Body weight moves forward beyond foot & leg in trailing position
Stance leg heel rise & continues until other leg heel strike
Muscle activity of terminal stance
Hip extension increase by gravity- 0° at heel rise
Abductor power decreases at onset of double support
Heel rise – passive; starting to PF
Explain pre-swing
Final stage of stance phase
Second double support interval
Body weight transfer to opposite limb
Begins with other leg initial contact & ends with stance leg toe-off
Muscle activity
Ground contact of opposite leg results in:
↑ ankle plantar flexion and toe flexors - concentric PFs and toe flexors
↑ knee flexion- concentric hamstrings
↓ hip extension - momentum
Explain initial swing
Begins when swing leg foot is lifted & ends when foot is opposite the stance leg
Muscle activity of initial swing
Hip flexion– initial concentric action to propel limb forward, assisted by gravity & momentum.
Knee flexion- hamstrings concentric contraction from pre-swing.
Ankle - concentric dorsiflexion to clear toes from ground
Explain terminal swing
Deceleration – final stage of swing
Begins when stance leg tibia vertical & ends when swing leg foot touches floor (heel-strike)
Muscle activity terminal swing
Hip flexion- momentum continues, eccentric control slows.
Knee – from flexion to extension by momentum- controlled by eccentric Hamstrings
Ankle dorsiflexion for heel strike - concentric
Weight distribution in gait
Initial contact - heel weight acceptance
Loading response and midstance - lateral border of foot first then on to MT heads
Terminal stance - heel off; more weight on MT heads and Hallux
Pre-swing - toe off; weight on toes phalanges