Week 1- Kinematics of Human Movement Flashcards
Kinematics
- Branch of mechanics that describes the motion of a body
- No reference to force/torque
Displacement
Change in position/time
Translation
- Linear motion
- All parts move together
Rotation
Rigid body moves in a circular path around some pivot point
Curvilinear motion
All parts move together in a nonlinear path
Direction of x-axis
- Coronal
- Side to side
Direction of y-axis
- Vertical
- Up and down
Direction of z-axis
- Anteroposterior
- Front to back
Degrees of freedom
Number of independent directions of movements allowed at a joint
Arthrokinematics
- Describes the motion occurring b/t articular surfaces of joints
- Maintains joint integrity
Roll (rock)
Multiple points along one rotating articular surface contact multiple points on another articular surface
Slide (glide)
A single point on one articular surface contact multiple points on another articular surface
Spin
A single point on one articular surface rotates on a single point on another articular surface
Convex-on-Concave Rule
Roll and slide occur in opposite directions
Concave-on-Convex Rule
Roll and slide occur in the same directions
How does the proximal or distal nature of the bony segment affect arthrokinematics?
It will determine if the concave is moving on the convex or vice versa
Close-Packed Position
- Joint Congruency: minimum
- Ligaments and Capsule: slack
- Joint Surfaces: unlocked
- Intra-articular Volume: Maximized
- Static Efficiency: inefficient
- Dynamic Safety: safe
Open-Packed Position
- Joint Congruency: maximum
- Ligaments and Capsule: tense
- Joint Surfaces: locked
- Intra-articular Volume: minimized
- Static Efficiency: efficient
- Dynamic Safety: dangerous
Categories for ROM
- Hypermobility
- Normal
- Hypomobility
Normal back extension ROM
25 degrees
Normal back flexion ROM
90 degrees
Normal back lateral flexion ROM
25 degrees R/L
Normal neck extension ROM
60 degrees
Normal neck flexion ROM
50 degrees
Normal neck lateral flexion
45 degrees R/L
Normal neck rotation ROM
80 degrees R/L
Normal hip extension ROM
30 degrees
Hypermobility
- May be normal, even advantageous
- =/= instability
- Can suggest underlying medical condition (Marfans, EDS, etc)
Hypomobility
Little ROM compared to normal limits