Introduction to Kinesiology Flashcards
What is biomechanics?
A discipline that uses principles of physics to quantitatively study how forces interact within a living body
What is physiology?
The biologic study of living organisms
What is Kinematics?
A branch of mechanics that describes the motion of a body, without regard to the forces or torques that may produce the motion
Two Types of Motions
1) Translation
2) Rotation
What is translation?
A linear motion in which all parts of a rigid body move parallel to and in the same direction as every other part of the body
Translation can occur in either a ___ line or a _____ line.
Straight (rectineal)
Curved (curvilinear)
What is rotation?
A motion in which an assumed rigid body moves in a circular path around some pivot point
A person’s COG _____ through space, and is powered by muscles that ____ the limbs.
translate
rotate
What is the pivot point for angular motion of the body or body parts called? (the point where motion of the rotating body is zero)
Axis of Rotation (AoR)
Active vs. Passive Movements
Active Movements are caused by stimulated muscle, such as when lifting a glass of water toward the mouth.
Passive Movements are caused by sources other than active muscle contraction, such as a push from another person, the pull of gravity, etc.
What is osteokinematics?
motion of bones relative to three cardinal planes of body
The axis of rotation is typically located through the _____ member of the joint.
Convex
Degrees of Freedom
The number of independent directions of movements allowed at a joint
The number of permitted planes of angular motion at a joint
A joint can have up to how many degrees of angular freedom and why?
3, corresponding to the 3 cardinal planes
How many degrees of freedom does the shoulder have? Wrist? Elbow? Explain why for each
Shoulder: 3 (one for each plane)
Wrist: 2 (rotation within sagittal and frontal planes)
Elbow: 1
What are accessory movements?
Slight, passive, nonvolitional movements allowed in most joints that are used to test the health of the joint (aka joint play)
What may excessive joint translation (or joint play) indicate?
ligamentous injury or abnormal laxity
What may a reduction in joint translation (or joint play) indicate?
pathologic stiffness within surrounding periarticular connective tissues
Describe a proximal-on-distal segment and give an example
The proximal segment can rotate against the relatively fixed distal segment
Knee Flexion Example:
LAQ - The femur is fixed and the tibia rotates against it. Therefore it is known as tibial-on-femoral
Describe a distal-on-proximal segment and give an example
The distal segment can rotate against the relatively fixed proximal segment
Knee Flexion Example:
Squat - The tibia is fixed and the femur rotates against it. Therefore it is known as femoral-on-tibial
What is Arthrokinematics?
The motion that occurs between the articular surfaces of joints
What are the 3 fundamental movements that exist between curved joint surfaces?
1) Roll
2) Slide
3) Spin
Describe Rolling
Multiple points along one rotating articular surface contact multiple points on another articular surface
Describe Sliding
A single point on one articular surface contacts multiple points on another articular surface
Describe Spinning
A single point on one articular surface rotates on a single point on another articular surface
In a convex-on-concave movement what direction does the convex segment roll? What way does it slide?
Roll occurs in the direction of the movement and slide occur in the opposite direction of the movement
In a concave-on-convex movement what direction does the concave segment roll? What way does it slide?
Roll and slide both occur in the same direction of the movement
What is a close-packed position?
The unique position of most joints where the articular surfaces are most congruent and the ligaments are maximally taut
What is a loose-packed position?
The positions of most synovial joints of the body in which the articular surfaces are least congruent and the ligaments are slackened, which allows for an increase in accessory movements
What is kinetics?
A branch of the study of mechanics that describes effect of forces and torques on the body
What is a force?
push or pull that produces, arrests, or modifies a movement
Force = ?
F = (m) that receives the push or pull multiplied by acceleration (a) of mass
Force that acts on a body is often referred to generically as a ____.
Load
7 Types of Loads Applied to the MSK System
1) Unloaded
2) Tension
3) Compression
4) Bending
5) Shear
6) Torsion
7) Combined Loading
Stress vs. Strain
Stress is the force generated as a tissue resists deformation, divided by its cross-sectional area
Strain is the ratio of a tissue’s deformed length to its original length
Define Viscoelasticity
The property of a material expressed by a changing stress-strain relationship over time
What is creep?
A progressive strain of a material when exposed to a constant load over time
Creep is reversible while ___ deformation is not
Plastic
What phenomenon explains why a person is taller in the morning than they are at night?
Creep of the IVD’s
Describe how the stress-strain curve changes as the rate of loading changes
The slope of stress-strain curve increases when the rate of loading increases
2 Sets of Forces that act on the musculoskeletal system
1) Internal
2) External
Internal vs. External Forces
Internal Forces are either actively or passively produced from structures located within body
External Forces are produced by forces acting from outside body
Torque = ?
Force multiplied by the moment arm produced
Force acting without a moment arm can push and pull an object generally in a ____ fashion, whereas torque ____ an object around AoR
Linear
Rotates
2 Requirements of a muscle to be able to produce torque
1) It must produce a force in the plane perpendicular to AoR of interest
2) It must act with associated moment arm distance > zero
What is the relationship between internal and external torque during a isometric contraction?
internal torque = external torque
What is the relationship between internal and external torque during a concentric contraction?
internal torque > external torque
What is the relationship between internal and external torque during a eccentric contraction?
external torque > internal torque
