Intro to Kinesiology Flashcards
What is kinematics?
Describes motion without considering the cause.
What concepts relate to kinematics?
- Linear displacement
- Linear velocity
- Linear acceleration
- Angular displacement
- Angular velocity
- Angular acceleration
- Osteokinematics
- Arthrokinematics
What is kinetics?
Describes the causes of movement.
What concepts relate to kinetics?
- Force
- Mass
- Inertia
- Weight
- Pressure
- Moment of Force
- Momentum
What is linear (translation) motion?
When all parts of a rigid body move parallel to and in the same direction as every other part of the body.
- Can be rectilinear or curvilinear and is measured in meters or feet
What is angular (rotation) motion?
Motion in which an assumed rigid body moves in a circular path around some pivot point.
- Measure in degrees or radians
What is osteokinematics?
It is a form of kinematics that describes motion of bones relative to the sagittal, frontal, or horizontal planes.
What is the axis of rotation?
The pivot point for angular motion. Describes how bones rotate about an axis that is perpendicular to the plane of motion.
What are the axes of rotation for the sagittal, frontal, and transverse planes?
Sagittal plane –> M/L axis
Frontal –> A/P axis
Transverse –> Vertical Axis
What are Degrees of Freedom?
Number of independent directions of movement allowed at a joint.
Uniaxial joint = 1 DOF
Biaxial joint = 2 DOF
Triaxial joint = 3 DOF
What is the name for when a proximal segment moves on a relatively fixed distal segment?
Closed Kinetic Chain (CKC)
What is the name for when a distal segment moves on a relatively fixed proximal segment?
Open Kinetic Chain (OKC)
What is Arthrokinematics?
Describes the motion that occurs between joint surfaces.
In most joints, one surface is convex and one is concave.
What is the benefit of the convex-concave relationship?
- Improves joint congruency
- Increases surfaces area for dissipating contact forces
- Helps guide motion between bones
Define the roll of a joint in arthrokinematics.
Multiple points along one rotating articular surface contact multiple points on another articular surface.
Define the glide of a joint in arthrokinematics.
A single point on one articular surface contacts multiple points on another articular surface.
Define the spin of a joint in arthrokinematics.
A single point on one articular surface rotates on a single point on another articular surface.
What determines the glide of a joint?
The convex-concave rule.
Which direction will the glide of a joint occur if the joint surfaces are convex on concave?
It will move in the OPPOSITE direction.
Which direction will the glide of a joint occur if the joint surfaces are concave on convex?
It will move in the SAME direction.
Describe the closed-packed position.
- It is the position of maximal congruency of a joint.
- Typically seen near or at end range.
- Most ligaments and capsule are taut and the joint is stable.
- There is minimal accessory movement.
Describe the loose-packed position.
- It is the position with the least amount of congruency near midrange.
- Ligaments and capsule on slack.
- Allows for increased accessory movement
- Often where joint mobility assessments are done.
What is force? What are the different types of forces applied to MSK system?
Force = push or pull that produces, arrest, or modifies movement.
Types = unloaded, tension, compression, bending, shear, torsion, combined loading
What 2 regions are included in the elastic region on the stress-strain curve?
- Toe region
2. Linear region
Define the toe region and the linear region on the stress-strain curve.
Toe Region = area that must be drawn taut before tension is measured.
Linear Region = after slack is taken up; linear relationship between stress and strain.
*If stretched within the elastic region, tissue will return to original length.
What 2 points are included in the plastic regions of the stress-strain curve?
- Yield point
2. Ultimate failure point
Define the yield point and the ultimate failure point on the stress-strain curve.
Yield point = elongation occurs beyond physiologic range
Ultimate failure point = point where tissue is partially or completely separated
What are viscoelastic tissues in the MSK system dependent on?
Time and rate
What is creep?
It is a property of viscoelasticity that describes progressive strain of a material that is exposed to a constant load over time.
Ex: Vertebral disc
What is an internal force?
A force produced within the body. It can be active or passive.
What is an external force?
A force produced outside of the body.
What is a force vector?
A depiction of force drawn as an arrow specified by magnitude and direction.
What is a moment arm?
The perpendicular distance between axis of rotation of the joint and the force.
*Product of force and its moment arm produce torque.
What is internal torque?
A product if internal force and internal moment arm.
What is an internal moment arm?
Perpendicular distance between axis of rotation and internal force.
What is external torque?
A product of the external force and external moment arm.
What is an external moment arm?
Perpendicular distance between axis or rotation and external force.
Define a lever.
A simple machine with rigid rod suspended across pivot point.
What is a pivot point?
A fulcrum.
What are the dominant forces involved in MSK levers?
- Force produced by muscle
- Gravity
- Physical contact with the environment
Define a 1st class lever.
When the axis of rotation is between the opposing forces.
Best designed for balance.
Define a 2nd class lever.
When the axis of rotation is located at one end, resistance in middle and force at other end.
Rare in MSK system.
Define a 3rd class lever.
When the axis is at one end with the force in the middle and resistance at the opposite end.
Most common lever in human body.
