Gait and posture

Question 1

What sort of features of normal gait vary from person to person?

Answer 1

Stride length

Pelvic movement

Upper body position

Question 2

What does normal gait rely on?

Answer 2

Joints
- intact and functioning

Muscles
- adequate strength

Nerves
- CNS & PNS

Vision

• information about movement of head and body relative to surroundings
• important for the automatic balance responses to changes in surface conditions
• vestibular and auditory systems

Question 3

Why are gait changes seen in the elderly?

Answer 3

Reduction in muscle bulk

Reduction in strength and flexibility

Some loss of hearing and vision

Question 4

What sort of gait changes are seen in the elderly?

Answer 4

Reduction in velocity

Reduction in stride length but increase in steps

Decreased

• arm swing
• rotation of the pelvis

More flat foot approach to heel strike and push off

Question 5

Where does the centre of gravity lie when standing?

Answer 5

Anterior to S2 vertebra

Means line of gravity is:

• slightly posterior to hip joints
• anterior to knee and ankle joints

Question 6

The line of gravity passes anterior to the ankle joint, this results in a ‘forward sway’? How is this counteracted?

Answer 6

By contraction of plantar flexor muscles

- particularly soleus

Question 7

What are the phases of the gait cycle?

Answer 7

Stance phase
- foot in contact with ground (60%)

Swing phase
- foot is in the air (40%)

Double support
- both feet on the ground (10%)

Question 8

What are the subdivisions of the stance phase?

Answer 8

1. Heel strike
2. Loading response
3. Mid-stance
4. Terminal stance
5. Pre-swing

Question 9

What are the subdivisions of the swing phase?

Answer 9

1. Initial swing
2. Mid-swing
3. Terminal swing

Question 10

What is a dynamic contraction?

Answer 10

Muscle contracts with a change in length.

• Concentric
• Eccentric

Question 11

What is a concentric contraction?

Answer 11

Muscle shortens while contracting

Question 12

What is an eccentric contraction?

Answer 12

Muscle lengthens while contracting.

Question 13

What is an isometric contraction?

Answer 13

Muscle contracts without changing in length.

Question 14

Which muscles are involved in the heel strike?

Answer 14

Lowering of forefoot to the ground is controlled by eccentric contraction of tibialis anterior

Deceleration of forward momentum – achieved by hip extension by gluteus maximus

Preservation of longitudinal arch of foot by intrinsic muscles

Ankle and subtalar joints accommodate terrain

Question 15

What are the features of the loading response?

Answer 15

Foot comes into full contact with ground

Requires knee extension to prevent knee buckling under weight – quadriceps femoris

Continued hip extension and preservation of longitudinal arch

Question 16

What is the midstance part of the gait cycle?

Answer 16

Point at which opposite limb swings past stance limb.

Question 17

Which muscles are involved in the mid-stance part of the cycle?

Answer 17

Requires stabilisation of the pelvis to keep it level – abduction of hip

Achieved by contraction of:

• gluteus medius
• gluteus minimus
• tensor fasia lata

Question 18

What is the terminal stance?

Answer 18

Point at which the heeal starts to lift off the ground

Question 19

Which muscles are involved in the terminal stance part of the cycle?

Answer 19

Achieved by plantar flexors – soleus and gastocnemius

This also accelerates mass forward

Question 20

What is the pre-swing (toe-off)?

Answer 20

Final stage of stance phase – preparation for moving into swing phase

Question 21

How is the pre-swing achieved?

Answer 21

Powerful plantar flexion of digits to push off ground and accelerate mass forward

Slowing of hip extension and preparation for hip flexion – eccentric contraction of rectus femoris

Question 22

What is essential for toe-off and what is it stabilised by?

Answer 22

Hallux

Stabilised by

• adductor hallucis
• abductor hallucis brevis

Question 23

What sort of gait problems may result from a misaligned or missing hallux?

Answer 23

Weak push off (apropulsive gait) results in:

• shorter stride length
• decreased gait velocity

Question 24

Which muscles are involved in the initial and mid-swing?

Answer 24

Hip flexion carries limb forward

• iliopsoas
• rectus femoris

Toes & foot dorsiflexed to allow foot to clear the ground
- tibialis anterior

Aided by knee flexion to shorten limb
- hamstrings

Question 25

What happens during the terminal swing?

Answer 25

Knee flexion changes to extension to place foot in correct position ready for heel-strike
- quadriceps

Assisted by dorsiflexion of ankle
- tibialis anterior

Simultaneously, eccentric contraction of hamstring muscles decelerates limb in preparation for heel-strike

Question 26

What happens if an individual is unable to flex their knee?

Answer 26

Limb circumduction

• swinging leg moves in an arc rather than straight forwards
• increases ground clearance for the swing foot

Question 27

If the foot cannot be dorsiflexed which nerve is most likely damaged?

Answer 27

Due to paralysis of tibialis of anterior

- common peroneal (fibular) nerve

Question 28

Pelvic rotation reduces the vertical drop in centre of gravity. What muscles achieve this?

Answer 28

Stance Limb: internal rotation

• Gluteus medius and minimus
• Tensor fascia lata

Swing Limb: external rotation

• Piriformis
• Quadratus femoris
• Obturator internus and externus
• Superior and inferior gemelli

Question 29

What limits the vertical rise in centre of gravity during the gait cycle?

Answer 29

Knee flexion

Pelvic drop to swing side

Question 30

What are the causes of a Trendelenberg gait?

Answer 30

Stroke

Hip Osteoarthritis

Cerebral Palsy

Superior gluteal nerve damage

Question 31

What minmises the lateral shift in centre of gravity?

Answer 31

Adductors pull the knees into midline to limit lateral shift in gravity