Biomechanics Flashcards
Kinesiology
The study of the mechanics of human movement.
Biomechanics
The study of the mechanical laws governing the movement of living organisms.
Force
The interaction that creates work or physical change, calculated as mass × acceleration.
Range of Motion (ROM):
The measurement of movement around a specific joint or body part.
Note: Human movement requires joints to be both mobile and stable; joints should move through the proper ROM with control.
Angle of Muscle Pull:
The angle at which a muscle pulls relative to the long axis of the bone on which it pulls.
Kinetics
The study of forces acting on a mechanism.
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.
Muscular Force
Involves the contraction of a muscle while exerting a force and performing work. This can be:
Concentric (shortening)
Eccentric (lengthening)
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.
Joints typically needing greater mobility: Foot/ankle, hip, thoracic spine, shoulder, and wrist.
Joint Stability
The ability of the muscles around a joint to control movement or hold the joint in a fixed (stable) position.
Joints Needing Greater Stability: Knee, lumbar spine, cervical spine, and elbow.
Momentum
The quantity of motion of a moving body, measured as a product of its mass and velocity.
Linear Motion
Movement along a line, which can be straight or curved.
Angular Motion
Rotation around an axis.
Axis
The point of rotation around which a lever moves.
Displacement
The distance an object is displaced from a starting point.
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.
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 Formula: W = F × D, where W is work, F is force, and D is distance or displacement.
Power
The amount of force exerted by a muscle or group of muscles in a given amount of time.
Power Calculation: Work done in a unit of time = force × velocity.
Mechanical Work
The amount of energy transferred by a force, which is the product of force and distance.
Torque
The turning effect of an eccentric force, also known as the rotational analog of force.
Torque Calculation: Torque is determined by multiplying the force (effort) by the length of the force arm.
Force Arm: The distance between the fulcrum and the force or load application in a lever.
Rotary Motion
Movement around a fixed axis moving in a curved path.
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.
Sustained Force Movement
Movement that requires continuous muscle contractions to keep a load moving.
