Gait and posture Flashcards
(41 cards)
What is gait?
Cyclical activity that translocates the centre of the body mass in a forward direction e.g. walking or running
Generally symmetrical and rhythmic but each gait differs from person to person
what is bipedalism?
Walking on two limbs
Why did hominids develop bipedalism?
- becoming taller to see more of the landscape
- using upper limbs for climbing
- greater movement economy on the ground
everybody has a unique gait because gait depends on:
Stride length – determined by by height / leg length
Pelvic movement
Upper body position
Weight and weight carriage
Clothing
Shoes / footwear
Age
Normal gait depends on:
Vestibular system
Peripheral nerves
visual system
Motor pathways
Basal ganglia = initiation of movement and coordination of movement
Reflexes and muscle tone being pain free
The role of standing in gait
supports body weight
minimises energy expenditure
Where is the centre of gravity?
The centre of gravity =
anterior to S2 vertebra
slightly posterior to the hips
anterior to knee and ankle
What is the most stable position of the knees and hips
Extension (not bent)
In standing, the tendency to fall forward is called
sway
This is counteracted by contraction of soleus
What is muscle tone and what are the changes of muscle tone called?
Muscle tone is a feature of skeletal muscle – in the limbs and body wall that is deemed the “firmness”
Hypotonia = reduced muscle tone - ’floppy’
Hypertonia = increased muscle tone - ‘spasticity’ and stiffness
Why is muscle tone important?
It helps to stabilise joints and maintain our posture
What systems control muscle tone and posture?
sensory inputs, spinal reflexes, descending tracts; the vestibular system and the vestibulospinal tracts important for standing upright
Cerebellar outputs to brainstem and cerebral cortex also involved in postural control.
What are the 2 phases of the gait cycle?
Stance phase (foot in contact with ground; 60% cycle)
Swing phase (foot is in the air; 40% cycle)
What is stance phrase comprised of?
Heel strike Loading response Mid-stance Terminal stance Pre-swing
What is swing phase comprised of?
Initial swing
Mid-swing
Terminal swing
2 types of muscle contraction are:
Isotonic: concentric (shorten) and eccentric contraction (Relax and lengthen)
Isometric: increase in tension of the muscle but it doesn’t change length and there is no movement
Heel strike
Begins when the heel strikes ground
Lowering of forefoot to the ground is by the controlled lengthening / relaxation (eccentric contraction) of tibialis anterior
Deceleration of forward momentum due to hip extension (gluteus maximus)
Ankle and subtalar joints accommodate terrain
loading response
Foot comes into full contact with ground
Body weight is transferred to stance limb
Quadriceps femoris is key in extending and stabilising the knee and preventing the knee from buckling under the body weight
Midstance
Opposite limb swings past stance limb
Requires stabilisation of the pelvis to keep it level – achieved by abduction of hip on stance side by gluteus medius and minimus
terminal stance
Heel of the stance limb starts to lift off the ground
Achieved by the plantarflexors – soleus and gastrocnemius
This also accelerates mass forward
Pre swing
Final stage of stance phase – preparation for moving into swing phase (i.e. prep for this limb leaving the ground and swinging forward)
Powerful plantarflexion of the digits to push off the ground and accelerate mass forward
In preparation for hip flexion, rectus femoris starts to relax / lengthen (eccentric contraction)
Hallux is essential for:
toe off
stabilised by adductor hallucis and abductor hallucis brevis
Weak push off (‘apropulsive’ gait) from the toe results in:
shorter stride length
decreased gait velocity
initial and mid swing
Hip flexion carries limb forward – iliopsoas and rectus femoris are active (shortening)
Toes & foot are dorsiflexed to allow the foot to clear the ground – tibialis anterior active
Plus knee flexion to shorten limb – hamstrings shorten
