Chapter 5: Concepts of Biomechanics Flashcards
Biomechanics
The study of the mechanical laws governing movement of living organisms.
Kinesiology
The study of the mechanics of human movement.
Anatomical Position
The anatomically neutral body position facing forward with the arms at the sides of the body and palms and toes pointing straight ahead.
Anterior or ventral
Front of the body or toward the front relative to another reference point
Posterior or dorsal
Back of the body or toward the back relative to another reference point
Superior
Above a reference point
Inferior
Below a reference point
Proximal
Position closer to the center of the body relative to a reference point
Distal
Position farther from the reference point
Medial
Position relatively closer to the midline of the body
Lateral
Position relatively farther from the midline of the body
Prone
Lying facedown
Supine
Lying on one’s backside
Deep
Further beneath the surface relative to another reference point
Superficial
Closer to the surface relative to another reference point
Unilateral
Refers to only one side
Bilateral
Refers to both sides
Ipsilateral
On the same side
Contralateral
On the opposite side
Caudal
Toward the bottom
Cephalic
Toward the head
Volar
Relating to the palm of the hand or sole of the foot
Abduction
Movement away from the midline
Adduction
Movement toward the midline
Flexion
Movement decreasing the angle between two body parts
Extension
Movement increasing the angle between two body parts
Lateral flexion
Flexion in the frontal plane
Protraction
Abduction of the scapula
Retraction
Adduction of the scapula
Elevation
Movement in a superior direction
Depression
Movement in an inferior direction
Plantar flexion
Extension of the foot downward (inferiorly)
Dorsiflexion
Flexion of the foot upward (superiorly)
External rotation
Rotational movement away from the midline
Internal rotation
Rotational movement toward the midline
Circumduction
Circular movement of a limb extending from the joint where the movement is controlled
Inversion
Movement of the sole of the foot toward the median plane
Eversion
Movement of the sole of the foot away from the median plane
Pronation
Turning the palm or arch of the foot down
Supination
Turning the palm or arch of the foot up
Hyperextension
Position that extends beyond anatomical neutral
Ipsilateral
Same-side movement
Contralateral
Opposite-side movement
Lateral
Situated away from the midline
Medial
Situated toward or closer to the midline
Frontal Plane
An imaginary line that divides the body into anterior and posterior halves.
Sagittal Plane
An imaginary line that divides the body into left and right halves.
Transverse Plane
An imaginary line that divides the body into inferior and superior halves.
Range of Motion
The measurement of movement around a specific joint or body part.
Balance
An even distribution of weight enabling someone or something to maintain its center of gravity within a base of support.
Equilibrium
A state in which opposing forces or influences are balanced.
Stability
The ability to control and maintain control of joint movement or body position.
Center of Gravity
The hypothetical position in the body where the combined mass appears to be concentrated and the point around which gravity appears to act.
Base of Support
The area beneath an object or person that includes every point of contact that the object or person makes with the supporting surface.
Gravity
The attraction between objects and the Earth.
Muscular Force
Involves the contraction of a muscle while exerting a force and performing work. It can be concentric (shortening), eccentric (lengthening), or isometric (tension without joint movement).
Dynamic Balance
The ability to remain upright and balanced when the body and/or arms and legs are in motion.
Static Balance
The ability to remain upright and balanced when the body is at rest.
Mass
The amount of matter in an object.
Weight
The gravitational force of attraction on an object.
Line of Gravity
A vertical line straight through the center of gravity.
Joint Mobility
The degree of movement around a joint before movement is restricted by surrounding tissues.
Joint Stability
The ability of the muscles around a joint to control movement or hold the joint in a fixed (stable) position.
Laws of Motion
The laws of physics describing movement.
Newton’s first law of motion
Newton’s first law states that a body in motion tends to stay in motion while a body at rest tends to stay at rest unless acted on by an outside force.
Force
The interaction that creates work or physical change. Its components are magnitude, direction, point of application, and line of action.
Inertia
The resistance to action or change and describes the acceleration and deceleration of the human body.
Acceleration
The rate of change of velocity.
Deceleration
A special type of acceleration where a person or object is slowing down.
Newton’s second law of motion
First, a change in acceleration of mass occurs in the same direction of the force causing it. Second, the change of acceleration is directly proportional to the force causing it and inversely proportional to the mass of the body.
Velocity
The speed of an object and the direction it takes while moving.
Force equation
F = m x a
Force-Velocity Curve
A representation of the inverse relationship between force and velocity in muscle contraction.
Power equation
F x velocity = P
Acceleration equation
a = change in v / change in t
Momentum
The quantity of motion of a moving body, measured as a product of its mass and velocity.
Newton’s third law of motion
Newton’s third law states that for every action, there is an opposite and equal reaction.
Speed
The ability to move the body in one direction as fast as possible.
Ground Reaction Force
The force the ground exerts on a body it is in contact with.
Friction
The resistance of relative motion that one surface or object encounters when moving over another.
Compression Force
The force of two surfaces pressing toward one another.
Tensile Force
The force when two surfaces pull apart from one another.
Shear Force
The force of two surfaces moving across one another.
Muscular Contraction
The shortening or resistance to lengthening of a muscle fiber.
Linear Motion
Movement along a line, straight or curved.
Angular Motion
Rotation around an axis.
Axis
Point of rotation around which a lever moves.
Displacement
The distance an object is displaced from a starting point.
Distance
The total or sum of the length an object travels.
Angular Displacement
The change of location of an object that is rotating about an axis.
Linear Displacement
The distance an object moves in a straight line.
Kinetics
The study of forces acting on a mechanism.
Mechanical Advantage
The ratio of force that creates meaningful movement compared to the force applied to generate the movement.
Work
Force times distance measured in foot-pounds.
Work equation
W = F x D
Power
The combination of strength and speed—the ability for a muscle to generate maximal tension as quickly as possible.
Mechanical Work
The amount of energy transferred by a force, the product of force and distance.
Levers
A rigid or semirigid bar rotating around a fixed point when force is applied to one end.
Fulcrum
The point on which a lever rests or is supported and on which it pivots.
Effort Arm
The portion of the lever arm between the applied effort and the axis.
Lever Arm
The rigid bar portion of a lever that rotates around the fulcrum.
Resistance Arm
The portion of the lever arm between the load and the axis.
Moment Arm
The perpendicular distance between the fulcrum and the line of the force being applied.
First Class Lever
For a first-class lever, the fulcrum (axis) is located between the effort and the load (resistance).
Second Class Lever
For a second-class lever, the load (resistance) is located between the fulcrum (axis) and the effort.
Third Class Lever
For a third-class lever, the effort is between the fulcrum (axis) and the load (resistance).
Torque
Force applied that results in rotation about an axis.
Rotary Motion
The movement around a fixed axis moving in a curved path.
Force Arm
The distance between the fulcrum and the force or load application in a lever.
Origin
The proximal muscular attachment point to a bone.
Insertion
The distal muscular attachment point to a bone.
Agonist
The primary muscle used for a mechanical movement.
Synergist
Muscle(s) supporting the mechanical movement of a prime mover.
Antagonist
Muscle(s) opposing the mechanical movement of a prime mover.
Sherrington’s Law of Reciprocal Inhibition
A law that states that for every muscle activation, there is a corresponding inhibition of the opposing muscle.
Stabilizer Muscles
The muscles playing the role of stabilizing or minimizing joint movement.
Length-Tension Relationship
The amount of tension a muscle can produce with respect to its length.
Force-Couple Relationship
Two or more muscles acting in different directions that influence the rotation of a joint in a specific direction.
Muscle Synergies
The activation of a group of muscles to generate movement around a particular joint.
Innervation
The distribution or supply of nerves.
