Gait cycle/mechanics

Question 1

Gait cycle

Answer 1

Walking is the result of a cyclic series of movements.
Only shows walking and what’s happening to one leg.
Demos how there’s always one limb on the ground or two. Single or double leg support.

Question 2

Space

Answer 2

Stride length, Step length, Stride width, foot angle

Question 3

Time

Answer 3

Cadence, stride time, step time

Question 4

Displacement of centre of gravity:

Answer 4

• Where is the COG – Ant S2
• Displacement in a vertical movement
• Average displacement 5cm
• Min occurs during double limb support
• Max occurs during single limb support

Question 5

Key events during the gait cycle:
Stance phase

Answer 5

Stage at which lower limb is in contact with the ground
1. Heel contact
2. Foot flat, majority of foot is on the ground, main trunk of the body is behind the foot
3. Mid stance, foot, lower limb and trunk all directly above each other
4. Heel off, COG now Infront of that limb
5. Toe off

Question 6

Key events during the gait cycle: Swing phase

Answer 6

When leg is off the ground
1. Acceleration
2. Mid swing
3. Deceleration

Question 7

Phases of walking gait cycle breakdown.
Stage 1 initial contact & heel strike:

Answer 7

Double leg support
Hip flexion 20deg
Knee flexion 0
DF 0

Movers: Quads, Glut max, Tib ant
Stabilisers: QL, ITB, Glut min & med
Pelvis laterally tilted and posteriorly rotated

Question 8

Stage 2 - loading response & flat foot

Answer 8

Double leg support
Hip flexion 20deg
Knee flexion 20
DF 5

Movers: Quads, Glut max, Gastrocnemius
Stabilisers: QL, ITB, Glut min & med
Pelvis laterally tilted, no rotation

Question 9

Stage 3 - mid stance

Answer 9

Double leg support
Hip flexion 0deg
Knee flexion 5
DF 5

Movers: Quads, Glut max, Gastrocnemius
Stabilisers: QL, ITB, Glut min & med
Pelvis not tilted but anteriorly rotated

Question 10

Why don’t we walk level?

Answer 10

There is a rise and a fall of the body and a rotation. Counter nutation of the trunk – when the pelvis rotates e.g., left, trunk will rotate right to counterbalance. Helps maintain balance when moving.

Question 11

Whats the loading response?

Answer 11

• Gait cycle normally only shows what’s happening from the hip downwards.
• However, in this phase it talks about the pelvis and SI ligaments.
• The ligaments preload as they know foot flat is coming so bodies COG will move from posterior to central to anterior.

Question 12

Internal Influencing factors of Gait

Answer 12

1. Vertical displacement
2. COG
3. Ant/Post rot
4. Muscle power
5. Feedback
6. Femoral angle of inclanation
7. Q angle
8. Patella tracking
9. Role of talus

• Single or double leg displacement
• Knee flexion
• Physiologic valgus at the knee
• Knee, ankle, foot interactions

Question 13

External Influencing factors of Gait

Answer 13

• Gravity
• COG
• Inertia
• Ground reaction force (GRF)
• External sources of force

Question 14

Pathological Influencing factors of Gait

Answer 14

• Osteoarthritis
• Rheumatoid arthritis
• Congenital dysplasia of the hip