Gait Kinetics and Kinematics

Question 1

What are the 3 methods of gait measurement?

Answer 1

1. Kinetics
2. Kinematics
3. Spatial Temporal

Question 2

What is kinetics?

Answer 2

internal and external forces

Question 3

What is kinematics?

Answer 3

gait phases, ROM, muscle activity

Question 4

What is spatial temporal?

Answer 4

velocity and step length

Question 5

What are some examples of two dimensional gait analyses?

Answer 5

• surface mat: good for estimating COP and COM (spatial/temporal and kinematics)
  -markers: used to document ROM and movement during gait
• one camera:

Question 6

What are graphs used for?

Answer 6

For:
- Joint ROM
- GRF
- Power and movements

Question 7

What is a zenomat and how does it work?

Answer 7

it provides a spatial temporal output and gives a visual video of foot prints

Question 8

What does 3D motion capture?

Answer 8

• body kinematics
• position velocity
• acceleration
• GRF
• Joint movements (indirectly)
• Powers

Question 10

What does kinetics refer to ?

Answer 10

1. GRF= external forces
2. Moments= force to cause rotation around a joint (internal and external moments)
3. Power= Force/Time (watts), concentric v eccentric

Question 10

Gait moments: internal v external moments

Answer 10

Internal moments: created by contraction of the muscle, joint ligaments, and fascia/joint capsule
External moments: created by the landing surface (GRF)

Question 10

What is the purpose of internal moments?

Answer 10

To counteract the forces from the ground

Question 11

Why does each joint create a moment (torque/force at the joint)?

Answer 11

1. Stabilize/control- most of stance
2. Produce Movement

Question 12

What are some characteristics of internal moments through the gait cycle?

Answer 12

• measured in % of Newtons/body weight
• negative values: flexor movement
• positive values: extension movement
• norms are in gray areas
• Can be a sum of all joints of individual joint internal moments

Question 13

What are internal movements and what do they do?

Answer 13

1. Internal moments are total amount of force created by muscle/joint, ligament/joint capsule/ fascia
2. Extensor movements: support for body on surface (quads, sole-gastroc)
3. Flexor moments: pull away from surface (illiopsoas, dorsiflexors)

Question 14

How is power defined in gait kinetics?

Answer 14

• Power is energy/time= the amount of energy produced overtime
• power is measured in watt or joules/sec
• structures can absorb/create power: muscles, tissues

Question 15

How is greater power created?

Answer 15

When an action is created/performed in a shorter time.

Question 16

What is negative power?

Answer 16

• Absorption of power
• Eccentric movements

Question 17

What is positive power?

Answer 17

• Creation of power
• Concentric movements

Question 18

How is power analyzed?

Answer 18

• Analyzes either joint power or total joint power at specific point in the gait cycle
• Graphs: Concentric power is above null line, Eccentric power is anything below null line

Question 19

What are some important clinical implications of power in normal gait (at ankle, knee, and hip)?

Answer 19

• Plantar flexors: provide important propulsive energy during push off
• Hip flexors: provide propulsive forces during pull off
• Knee: power is relatively low and often negative, indicating eccentric activity in knee extensors or flexors