3D Dimensional Gait Analysis (Quiz 3) Flashcards
Passenger Unit
- head, neck, trunk, arms, pelvis
- carried in normal gait, and doesnt directly contribute to the act of walking
- Responsible for its own postural integrity, and aligning itself over the locomotor unit
What % of body weight is passenger unit
70%
What is a major determinant of muscle action (passenger unit)
alignment over the legs
What is forward momentum important for
obtaining a normal gait pattern
Locomotor Unit
- Legs and Pelvis
- 57 muscles
- bony segments serve as levers
What are the 11 primary articulations in locomotor unit
- lumbosacral
- bilateral hip
- knee
- ankle
- subtalar
- metarsalphalangeal joints
Gait Cycle
defined from some particular event on one side of the body to the next occurance of that event on the same side of the body
Stride Length
- distance covered during one gait cycle
- measured from point on the reference foot to that same point later in gait
Step Length
distance between a point on one foot and the same point on the contralateral foot
Initial Contact Objectives
Perry
- Position foot correctly as it comes into contact with the floor
- transfer body weight to leading leg
- Stable load-bearing
Loading Response Objectives
Perry
- maintain smooth progression
- shock absorption
- Limb stabilization
*** body reaches lowest vertical position & highest forward velocity **
Midstance Objectives
Perry
- stable weight bearing
- maintain forward progression
- body reaches highest vertical position & lowest forward velocity
Terminal Stance Objectives
Perry
- provide forward accelaeration of the body and insure an adequate step length
- stable weight bearing
- allow body mas to progress over foot
- prepare for initial contact of the opposite leg
Pre-Swing Objectives
Perry
- prepare leg for swing phase
- aid transfer of body weight to opposite leg
- continued floor contact assists body balance as body weight is transferred to the other limb
Initial Swing Objectives
Perry
- Floor clearance for limb advancement
- Actions are to facilitate progression and allow for a variable cadence
Midswing Objectives
Perry
- Floor Clearance
- Limb Advancement
Terminal Swing Objectives
Perry
- Complete Step Length
- Prepare for initial contact
Ground Reaction Forces
equal in magnitude and opposite in direction to those being experienced (exerted) by the weight-bearing limb
What is joint stability in the stance leg influenced by
relation of the GRF vector to the proximity of the joint axis of rotation, which creates a moment
TRUE OR FALSE
Joint moment curves represent the net joint moments
TRUE
muscle co-contractions are not taken into account
Link Segment Model Assumptions
- each segment has fixed mass
- location of COM remains fixed during the movement
- joints are considered to be hidge joints
- joints are frictionless
- mass moment of inertia of each segment is constant
- length remains constant
Link Segment Model Limitations
- foot and trunk are not represented well with only a signle rigid segment
- limb segments and joint interfaces are assumed to be rigid
- can only calculate net joint moments
- cannot meaningfully interpret joint forces
Inverse Dynamics Solution
between the anthropomorphic data, the assumptions regarding the link-segment model, and the model’s limitations, there is a lot of room for error to creep into the process
error propigates proximally up the leg
External moment
moment that is created by external forces acting on the body that tend to cause rotation about the joint; also referred to as a demand moment
Internal Moment
Moment that is created by muscles, ligaments, friciton, or other structural constrains; also referred to as a “response” moment
Joint Power
- rate of work
- product of net joint moment and joint angular velocity
- if both are in the same direction positive joint power is produced
- if both are in opposite direction power output is negative
Metabolic Energy
physiological energy expenditure at rest or during exercise can be measured by the body’s heat and work production
Indirect Calorimetry
- measuring O2 consumption
Rate of O2 Consumption
ml of O2 consumed per kg body mass per unit time
O2 Cost
amount of oxygen consumed per kilogram body mass per unit distance traveled
TRUE OR FALSE
ROM increases with walking speed
True
What effect does walking speed have on joint power
power increases proportionally to walking speed
