Gait Kinetics

Question 1

F=MA

Answer 1

Force =mass*acceleration

Question 2

A push or pull can do what to movement

Answer 2

Produce, stop or modify movement

Question 3

Magnitude(N)

Answer 3

?

Question 4

Direction (sense)

Answer 4

?

Question 5

Point of Application

Answer 5

?

Question 6

Spatial orientation

Answer 6

orientation of line stated as an angular position in regard to an object ie..bony segment

Question 7

What external forces act on the body

Answer 7

Gravity, External loads, contact, friction, buoyancy, Inertia

Question 8

What internal forces act on the body

Answer 8

Active–Muscle

Passive–Intramuscular connective tissue, ligaments, joint capsules

Question 9

What are the four descriptors of force?

Answer 9

Magnitude
Direction
Point of Application
Spatial Orientation(orientation of the line stated as an angular position in regard to an object ie…bony segment

Question 10

What is Newton’s Third Law (Law of Reaction)

Answer 10

For every action there is a reaction of equal magnitude, but in opposite direction

Question 11

What is Moment Torque?

Answer 11

Force acting a distance from the center of rotation of a segment.
Torque=F*D
-(d)-moment arm is the perpendicular distance from the force vector to the center of rotation

Question 12

Walking Kinetic External Forces

Answer 12

Primarily generated by the ground

Consist of vertical, anterior-posterior, and mefial lateral forces

Question 13

Walking Kinetics Internal Forces

Answer 13

Primarily generated by muscle and other soft tissue such as ligaments, tendons, and joint capsule
Measured by 3D gait analysis combine kinematic and kinetic data
also EMG is helpful to determine the onset and offset of muscles

Question 14

Walking vs. Running: Vertical Ground Reaction Forces

Answer 14

Heel COntact 0-1
Maximal weight acceptance >10 bodyweight
Mid stance 6
Push off >10 bodyweight
Toe-off 1

Question 15

During gait what forces act the most on the body?

Answer 15

Vertical Forces, there is a peak magnitude in vertical force

Question 16

Saggital Plane Kinetics External moments are created by

Answer 16

Ankle Plantarflexion
Knee Flexion
Hip Flexion

Question 17

Saggital Plane internal moment arms are created by

Answer 17

Ankle dorsiflexion
knee extension
hip extension

Question 18

A vector or moment arm that is in front of the hip

Answer 18

causes hip flexion

Question 19

a moment or vector behind the ankly

Answer 19

plantar flex ankle to slowly lower foot to ground

Question 20

Moment arm behind the knee

Answer 20

encouraged knee flexion

Question 21

Rearfoot strike running causes the ground reaction force to be absorbed by

Answer 21

BONE

Question 22

Forefoot strike running causes the ground reaction force to be absorbed how?

Answer 22

The ground reaction force dorsiflexes the foot causing eccectric plantarflexion which means the internal force muscle actions absorbs the GRF.

Question 23

Frontal Plane Kinetics; loading phase

Answer 23

Ground creates external adduction moment at hip and knee.

Body must create an internal abductor moment at both the hip and knee

Question 24

Moment Terminology

Answer 24

Be careful when reading studies reporting moments
you must identify in the methods whether the moments reports in the results are internal (created within body) oe external (typically result of GRF)
example…the findings of a study reporting large external abduction moments at the knee during a task would be equal to study reporting large internal adduction moments at eh knee for the same task.

Question 25

How does the dual innervation of the hamstrings help to reduce medial stress of the knee?

Answer 25

The dual innervation of the knee allows the lateral head/short head of the biceps femoris to activate individually and create an abduction moment to reduce the moment to reduce medial stress of the knee.

Question 26

Read under the pictures

Answer 26

Read under the pictures