Biomechanics And Kinesiology - Glossary Flashcards
Acceleration
- change in velocity of a body over time, expressed in linear and angular terms
Accessory movements
- slight, passive, nonvolitional movements allowed in most joints
Active force
- push or pull generated by stimulated muscle
Active movement
- motion caused by stimulated muscle
Agonist muscle
- muscle or muscle group that is most directly related to the initiation and execution of a particular movement
Anatomic position
- the generally agreed on the reference position of the body used to describe the location and movements of its parts
- person is standing fully upright, looking forward, arms resting by the side and the palms facing forwards
Angle-of-insertion
- angle formed between a tendon of a muscle and the long axis of the bone into which it inserts
Antagonist muscle
- muscle or muscle group that has the action opposite to a particular agonist muscle
Arthrokinematics
- motions of roll, slide, and spin that occur between curved articular surfaces of joints
Axial rotation
- angular motion of an object in a direction perpendicular to its longitudinal axis
Axis of rotation
- an imaginary lone extending through a joint around which rotation occurs
Bending
- effect of a force that deforms a material at right angles to its long axis
- bent tissue is compressed on its concave side and placed under tension on its convex side
Center of mass
- point at the exact center of an object’s mass
Close-packed position
- unique postion of most joints of the body where the articular surfaces are most congruent and the ligaments are maximally taut
Compliance
- the inverse of stiffness
Compression
- a force, applied perpendicularly to the contact surface, that pushes or pulls one object directly against another
Concentric activation
- activated muscle that shortens as it produces a pulling force
Creep
- a progressive strain of a material when exposed to a constant load over time
Degrees of freedom
- number of independent directions of movements allowed at a joint
Displacement
- change in the linear or angular position of an object
Distal-on-proximal segment kinematics
- type of movement in which the distal segment of a joint rotates relative to a fixed proximal segment
Distraction
- a force, applied perpendicularly to the contact surface, that pushes or pulls one object directly away from another
Eccentric activation
- activated muscle that is producing a pulling force while being elongated by another more dominant force
Elasticity
- property of a material demonstrated by its ability to return to its original length after the removal of a deforming force
External force
- push or pull produced by sources located outside the body
External moment arm
- perpendicular distance between an axis of rotation and the external force
External torque
- product of an external force and its external moment arm
Force
- a push or pull that produces, arrests, or modifies a motion
Force-couple
- two or more muscles acting in different linear directions, but producing a torque in the same rotary direction
Force of gravity
- potential acceleration of a body toward the center of the earth as a result of gravity
Friction
- resistance to movement between two contacting surfaces
Internal force
- push or pull produces by a structure located within the body
Internal moment arm
- perpendicular distance between the axis of rotation and the internal force
Internal torque
- product of an internal force and its internal moment arm
Isometric activation
- activated muscle that maintains a constant length as it produces a pulling force
Joint reaction force
- force that exists at a joint, developed in reaction to the net effect of internal and external forces
Kinematics
- branch of mechanics that describes the motion of a body, without regard to the forces or torques that may produce motion
Kinematic chain
- series of articulated segmented links
Kinetics
- branch of mechanics that describes the effect of forces and torques on the body
Leverage
- relative moment arm length possessed by a particular force
Line of force
- direction and orientation of a muscle’s force
Line of gravity
- direction and orientation of the gravitational pull on a body
Load
- the application of a force to a body
Longitudinal body
- axis that extends within and parallel to a long bone or body segment
Loose-packed position
- positions of most synovial joints of the body in which the articular surfaces are least congruent
Mass
- quantity of matter in an object
Mechanical advantage
- ratio of the internal moment arm to the external moment arm
Moment arm
- perpendicular distance between an axis of rotation and the line of force
Muscle action
- potential of a muscle to produce a torque within a particular plane of motion and rotation direction
- flexion, extension, pronation and supination
Osteokinematics
- motion of bones relative to the three cardinal, or principle, planes
Passive force
- push or pull generated by sources other than stimulated muscle
Passive movement
- motion produced by a source other than activated muscle
Plasticity
- property of a material demonstrated by remaining permanently deformed after the removal of a force
Pressure
- force divided by a surface area
Productive antagonism
- low-level tension within stretched connective tissue performs a useful function
Proximal-on-distal segment kinematics
- type of movement in which the proximal segment of a joint rotates relative to a fixed distal segment
Roll
- when multiple points on one rotating articular surface contact multiple points on another articular surface
Rotation
- angular motion in which a rigid body moves in a circular path around a pivot point or an axis of rotation
Scalar
- quantity that is completely specified by its magnitude and has no direction
Segment
- any part of a body or limb
Shear
- a force produced as two compressed objects slide past each other in opposite directions
Shock absorption
- the act of dissipating a force
Slide
- when a single point on one articular surface contacts multiple points on another articular surface
Spin
- when a single point on one articular surface rotates on a single point on another articular surface
Static linear equilibrium
- state of a body at rest in which the sum of all forces is equal to zero
Static rotary equilibrium
- state of a body at rest in which the sum of all torques is equal to zero
Stiffness
- ratio of stress to strain within an elastic material
Strain
- ratio of a tissue’s deformed length to its original length
Stress
- force generated as a tissue resists deformation, divided by its cross-sectional area
Synergists
- two or more muscles that cooperate to execute a particular movement
Tension
- application of one or more forces that pulls apart or separates a material
Torque
- a force multiplied by its moment arm
Torsion
- application of a force that twists a material around its longitudinal axis
Translation
- linear motion in which all parts of a rigid body move parallel to and in the same direction as every other point in the body
Vector
- quantity that is completely specified by its magnitude and direction
Velocity
- change in position of a body over time
Viscoelasticity
- property of a material expressed by a changing stress-strain relationship over time
Weight
- gravitational force acting on mass