Module 12: Human Gait

Question 1

What defines a gait cycle?

Answer 1

The period from one heel strike to the next, encompassing a complete sequence of walking events. It can be measured from any point in the cycle.

Question 2

What is the temporal definition of a step?

Answer 2

The time between when the heel of one leg strikes the ground and when the heel of the other leg strikes the ground

Question 3

What is the temporal definition of a stride?

Answer 3

The time between two consecutive heel strikes by the same leg, one complete gait cycle

Question 4

What is cadence?

Answer 4

The number of steps taken per minute.

Question 5

What are the phases of the gait cycle?

Answer 5

Stance: Foot in contact with the ground; Swing: Foot not in contact, moving forward.

Question 6

What is the double support phase?

Answer 6

When both feet are in contact with the floor simultaneously

Question 7

Name 3 characteristics of the swing phase.

Answer 7

1. Acceleration of the moving leg.
2. Continuous knee and hip flexion.
3. Deceleration of the limb’s anterior momentum.

Question 8

Name 3 characteristics of the stance phase.

Answer 8

1. Foot placed, heel first, for shock absorption. 2. Shock absorbed, forward momentum preserved. 3. COG moves anteriorly and higher with smaller (single foot) BOS 4. COG is anterior to stance limb. 5. Forefoot remains on the ground, knee flexion is required for ground clearance during swing.

Question 9

What are the 3 moments of the swing phase?

Answer 9

1. Acceleration: Toes leave ground until mid-swing. 2. Mid-swing: After acceleration until deceleration. 3. Deceleration: Swing limb anterior to stance limb until heel strike.

Question 10

What are the 5 moments of the stance phase?

Answer 10

1. Heel Strike (initial contact): Heel touches the ground until foot is flat on ground
2. Foot Flat (loading response): Just before foot flat until COG moves anteriorly over ankle
3. Mid Stance: Foot flat on ground until heel starts to leave ground
4. Heel Off (terminal stance): Heel leaves ground until toes begin to lift
5. Toes Off ( pre swing): Toes coming off ground until Initial Swing (foot off the ground)

Question 11

What are the joint positions of the hip, knee, and ankle during the acceleration phase of the initial swing?

Answer 11

Hip and knee: Flexing; Ankle: Dorsiflexing to avoid toe drag.

Question 12

What are the joint positions of the hip, knee, and ankle during mid-swing?

Answer 12

Hip and knee: Continued flexion (knee keeps foot raised); Ankle: May move to slight plantar flexion.

Question 13

What are the joint positions of the hip, knee, and ankle during the deceleration phase of the swing phase?

Answer 13

Hip: Continues to flex, driven by momentum; Knee: Flexing to extension, hamstrings slow movement down; Ankle: Dorsiflexors contract for proper position for heel strike.

Question 14

Which muscles are active during the swing phase, and what is their purpose?

Answer 14

Hip Flexors (Iliopsoas): Acceleration, flex hip and propel the limb forward; Plantar Flexors (Gastrocnemius, Soleus): Acceleration, forward movement of leg; Hamstrings: Deceleration, acting eccentrically to control hip flexion and slow knee extension; Dorsiflexors (Tibialis Anterior): Deceleration, proper foot position for heel strike and avoid toe drag in swing phase.

Question 15

What are the joint positions of the hip, knee, and ankle at initial heel contact?

Answer 15

Hip: Slight flexion; Knee: Full extension or slightly flexed (~5°); Ankle: Neutral or up to 10° of dorsiflexion/plantar flexion.

Question 16

What are the joint positions of the hip, knee, and ankle during the load response?

Answer 16

Hip: Flexion moving to extension; Knee: Flexing for shock absorption ( ~30°); Ankle: Controlled plantar flexion, slight eversion.

Question 17

What are the joint positions of the hip, knee, and ankle during mid-stance?

Answer 17

Hip: Continued extension (due to momentum); Knee: Slight flexion; Ankle: Minor dorsiflexion, possible eccentric dorsiflexors to control tibial movement.

Question 18

What are the joint positions of the hip, knee, and ankle during heel off?

Answer 18

Hip: Further extension; Knee: Flexing for push-off; Ankle: Full dorsiflexion as the heel rises, plantar flexors contract concentrically.

Question 19

What are the joint positions of the hip, knee, and ankle during toe off?

Answer 19

Hip: Flexing; Knee: Further flexion; Ankle: Plantar flexion for push-off.

Question 20

Which muscles are active during the load response phase, and what is their purpose?

Answer 20

Hip Extensors (Gluteus Maximus): Concentrically to extend hip; Quadriceps: Eccentrically to control knee flexion / absorb impact; Dorsiflexors (Tibialis Anterior): Eccentrically to control plantar flexion / lower foot to ground

Question 21

Which muscles are active during the heel off phase, and what is their purpose?

Answer 21

Hip Extensors (Gluteus Maximus): Contract slightly for extension when body moves forward. Plantar Flexors (Gastrocnemius, Soleus): Concentrically to provide propulsive force for push-off. Hip Flexors: Activate for swing phase.

Question 22

Which muscle stabilizes the pelvis during mid-stance in the frontal plane?

Answer 22

Hip Abductors (Gluteus Medius): Eccentrically to stabilize pelvis and prevent it from dropping toward swing limb.

Question 23

What are the requirements for efficient human gait?

Answer 23

Low Energy Expenditure, Utilization of Momentum, Kinetic and Potential Energy Transfer, Rhythmic Vertical Fluctuations of COG, Minimal Alteration in Body Structure or Gait Pattern

Question 24

At which moment of the stance phase does the center of gravity move anteriorly to the stance limb?

Answer 24

During the heel-off

Question 25

At which moment of the stance phase does knee flexion torque increase?

Answer 25

During the load response

Question 26

Which muscle contributes most to knee flexion during toe off?

Answer 26

Hamstrings

Question 27

Which muscles aid in proper foot clearance during the swing phase?

Answer 27

Dorsiflexors: tibialis anterior, extensor digitorum longus, extensor hallucis longus

Question 28

What movements occur in the trunk during the double support phase?

Answer 28

Rotation: Trunk rotates slightly around vertical axis in coordination with pelvis. Helps counterbalance swinging of arms and legs, maintaining stability. Lateral Tilt: Slight lateral tilt (side-to-side movement) of trunk as weight shifts from one leg to the other. Flexion / Extension: Subtle forward or backward movements of the trunk may occur to adjust COG for smooth propulsion in walking.

Question 29

What is the main difference between running and walking phases?

Answer 29

Running lacks double-stance phase; includes a period with no foot contact with the ground.

Question 30

What are the characteristics of arm movement during normal gait?

Answer 30

Reciprocal Motion: The upper limbs move reciprocally with the lower limbs; Primary Movement at the Shoulder: Most arm movement occurs at the shoulder joint, with a lesser degree of motion at the elbow joint. Shoulder movement begins slightly before elbow movement. Varied Range of Movement: The range of upper limb motion varies between individuals and depends on the walking velocity. Non-essential Nature: Upper limb movement is not critical for walking but contributes to overall gait efficiency and reduces fatigue by aiding momentum transfer. Compensation for Trunk Rotation: Arm swing helps counteract over-rotation of the lumbar spine caused by pelvic and spinal movements during gait. Velocity-dependent Motion: The extent of arm movement increases with faster walking speeds.

Question 31

List the differences between backward and forward walking.

Answer 31

Backward walking: Reduced Step Length, Toe strike replaces heel strike, Movement in posterior direction, Reduced speed, Increased cadence

Question 32

List factors that make walking upstairs more challenging than walking on level ground.

Answer 32

Greater Range of Hip and Knee Joint Movement, Vertical Translation of the Center of Gravity, Increased Joint Forces, Increased Risk of Falls due to smaller BOS, Increased Muscular Force Requirement

Question 33

During stair climbing, when is the compression force between the femur and patella greatest?

Answer 33

The stance phase on ascent when the knee is flexed ~ 60° (3x body weight)

Question 34

What are the different demands when going upstairs compared to downstairs?

Answer 34

Walking Upstairs: Concentric contraction of hip and knee extensors; Increased energy requirement; controlled balance due to vertical translation. Walking Downstairs: Eccentric contraction of quadriceps, gastrocnemius, hip extensors; Increased joint strain; Less energy requirement; Psychologically challenging