Optimizing Movement and Biomechanics Flashcards

Flashcards covering introductory biomechanics, human movement system concepts, reference frames, and kinesiology definitions.

APTA Vision

Transforming society by optimizing movement to improve the human experience.

Human Movement System (APTA Definition)

The integration of body systems that generate and maintain movement at all levels of bodily function.

Human Movement System (WUPT Definition)

Consists of the physiological organ systems that interact to produce and support movement of the body and its parts.

Generation & Control of Movement (GCM) Thread

A movement curriculum thread emphasizing the contributions of the nervous and musculoskeletal systems to movement.

Underpinnings of Movement (UOM) Thread

A movement curriculum thread emphasizing the contributions of the endocrine, cardiovascular, pulmonary, and integumentary systems to movement.

Diagnosis & Management of Movement Problems (DMMP) Thread

A movement curriculum thread elaborating on the interrelationships among Health Status, the Movement System, and Movement, as well as APTA's Patient/Client Management Model.

Moderators of Movement (MODM) Thread

A movement curriculum thread elaborating on relationships among movement, health condition, activities, participation, environmental factors, and personal factors.

Dynamic Knee Valgus

A movement impairment that increases compression laterally and tension medially at the knee joint.

Kinesiology

The study of human movement.

Biomechanics

The study of forces acting on and generated within the body, and the effects of these forces on tissues.

Scalar Quantity

A biomechanical parameter fully described by magnitude alone, such as mass, time, or length.

Vector Quantity

A biomechanical parameter fully described by both magnitude and direction, such as forces and moments.

Force

A push or a pull that produces, stops, or modifies a motion, calculated as $F = m \times a$ and measured in Newtons ($\text{N}$).

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.

Rotation

Angular motion in which a rigid body moves in a circular path around a pivot point or an axis of rotation.

Internal Force

A force produced by a structure located within the body, such as active muscle activation, ligament tension, or bone contact.

External Force

A force produced by sources located outside the body, such as gravity, physical contact, or external weights.

Mass

The quantity of matter in an object, which is a constant and measured in kilograms ($\text{kg}$).

Weight

The force exerted on a mass by gravitational acceleration ($\text{Weight} = m \times g$), measured in Newtons ($\text{N}$).

Newton's First Law of Inertia (Linear)

States that a body remains at rest or at a constant linear velocity except when compelled by an external force to change its state.

Newton's First Law of Inertia (Rotational)

States that a body remains at rest or at a constant angular velocity around an axis of rotation unless compelled by an external torque to change its state.

Newton's Second Law of Acceleration (Linear)

States that linear acceleration is directly proportional to the force causing it, takes place in the direction of the force, and is inversely proportional to body mass ($F = m \times a$).

Newton's Second Law of Acceleration (Rotational)

States that angular acceleration is directly proportional to torque, takes place in the same rotary direction, and is inversely proportional to mass moment of inertia.

Newton's Third Law of Action-Reaction

States that for every force or torque, there is an equal and opposite directed force or torque.

Moment (Torque)

The turning effect of a force on an object around an axis of rotation, calculated as $M = F \times d$ and measured in Newton-meters ($\text{N}\,\text{m}$).

Moment Arm

The perpendicular distance from an axis of rotation to the force vector or line of force.

Center of Mass (COM)

A point in space representing the mean position of the matter in a body, assumed in anatomical position to be just anterior to the sacrum.

Base of Support (BOS)

The area beneath a person or object that includes every point of contact made with the supporting surface.

Acceleration

The change in velocity of a body over time ($a = \frac{\Delta v}{\Delta t}$), expressed in linear ($\text{m/s}^2$) or angular ($\text{deg/s}^2$) terms.

Accessory Movements

Slight, passive, nonvolitional movements allowed in most joints, also called joint play.

Active Insufficiency

The inability of a two-joint or multi-joint muscle to generate an effective force when placed in a fully shortened position.

Adaptation

The adjustment of an organism or tissue to a change in internal or external conditions or circumstances.

Agonist Muscle

A muscle or muscle group that is most directly related to the initiation and execution of a particular motion.

Antagonist Muscle

A muscle or muscle group that has the action opposite of a particular agonist muscle.

Anisotropic

Having mechanical properties that are dependent upon the direction of loading.

Arthrokinematics

Motions of roll, slide, and spin that occur between curved articular surfaces of joints.

Atrophy

A wasting of tissues, organs, or the entire body from causes such as diminished cellular proliferation or function.

Axis of Rotation

An imaginary line extending through a joint around which rotation occurs.

Bending

A mechanical loading condition occurring under asymmetrical axial loading and torsion where one side of a material is loaded in compression and the opposite side in tension.

Breaking Strength

The stress level at which failure of a material occurs, causing a disruption of continuity of material.

Brittle

Describes a material that shows sudden failure without undergoing considerable plastic deformation.

Close-packed Position

The unique position of a joint where articular surfaces are most congruent and ligaments are maximally taut.

Compliance

The inverse of stiffness, indicating a material with a small modulus of elasticity that is easy to deform.

Compression

A force applied perpendicularly to a contact surface that pushes one object directly against another.

Creep

A progressive strain of a material when exposed to a constant load over time.

Deformation

A type of motion that involves local changes of shape within a body due to externally applied forces.

Degrees of Freedom

The number of independent directions of movement allowed at a joint, up to three translations and three rotations.

Density

Mass per unit volume of an object.

Displacement

The change in linear or angular position of an object ($d = r_{\text{final}} - r_{\text{initial}}$).

Series Elastic Components

Noncontractile muscle tissues that lie in series with active proteins, such as tendons and titin.

Parallel Elastic Components

Noncontractile muscle tissues that surround or lie in parallel with active proteins, such as extracellular connective tissue.

Elastic Region

The region of a stress-strain curve in which a loaded tissue recovers all energy used to deform it and undergoes no permanent deformation.

Elasticity

The property of a material demonstrated by its ability to return to its original length after removal of a deforming force.

Failure

The breaking or rupture of a material such that there is a discontinuity in the material.

Fatigue

Failure of a material at a stress level lower than breaking strength as a result of repeated loading and unloading cycles.

Muscular Fatigue

An exercise-induced decline in maximal voluntary muscle force or power despite maximal effort.

Force-Couple

Two or more muscles acting in different linear directions but producing torque in the same rotary direction.

Force-Velocity Curve

The theoretic relationship between force and velocity of muscle shortening or lengthening during maximal-effort muscle activation.

Friction

A force that opposes the relative motion or tendency of motion between two surfaces in contact.

Ground Reaction Force

The force exerted by the ground on a body in contact with it.

Hypermobility

Increased range of movement in joints, or joint laxity.

Hypertrophy

General increase in bulk of a tissue or organ not due to tumor formation.

Hypomobility

Restricted joint movement that limits normal range of motion.

Hysteresis

The difference in the load-deformation relationship during loading and unloading of a material resulting from a loss of energy as heat.

Inertia

The tendency of a physical body to oppose any force tending to move it from rest or to change its uniform motion.

Instantaneous Axis of Rotation (IAR)

A point that is momentarily at rest in both global and local reference frames.

Isotropy

A property exhibited when identical mechanical properties occur during loading in all directions.

Joint Reaction Force (JRF)

The force that exists at a joint, developed in reaction to the net effect of internal and external forces.

Kinematics

The branch of mechanics describing the motion of a body without regard to the forces or torques that produce the motion.

Kinetics

The branch of mechanics describing the effect of forces and torques on the body.

Length-Tension Curve

A curve reflecting that tension generation in skeletal muscle is a direct function of actin and myosin filament overlap.

Loose-packed Position

The position of synovial joints in which articular surfaces are least congruent and ligaments are slackened.

Mass Moment of Inertia

A quantity indicating a body's resistance to a change in angular velocity, calculated as $I = \sum m_i \times r_i^2$.

Mechanical Advantage

The ratio of the internal moment arm to the external moment arm.

Modulus of Elasticity (Young's Modulus)

The ratio of stress to strain for a given material ($E = \frac{\sigma}{\epsilon}$), representing tissue stiffness.

Concentric Contraction

Activated muscle shortening as it produces a pulling force, performing positive work.

Eccentric Contraction

Activated muscle producing a pulling force while being elongated by a dominant force, performing negative work.

Isometric Contraction

Activated muscle maintaining a constant length as it produces a pulling force.

Normal Stress

The internal resistive force per unit area under axial loading perpendicular to the plane of cut ($\sigma_{\text{normal}} = \frac{F}{A}$).

Osteokinematics

Motion of bones relative to the three cardinal or principal planes.

Passive Insufficiency

Shortness of a two-joint or multi-joint muscle preventing normal elongation over both joints simultaneously.

Plastic Region

The region of a stress-strain curve in which loaded tissue does not recover all energy and permanent deformation occurs.

Plasticity

The property of a material demonstrated by remaining permanently deformed after removal of a deforming force.

Poisson's Ratio

The ratio of deformations occurring in lateral directions to the axial direction under uniaxial tension.

Power

The rate of doing work, expressed linearly ($P = \frac{W}{\Delta t}$) or angularly ($P = M \times \omega$) in Watts ($\text{W}$).

Shear Force

A force produced parallel to the surface of a material as two compressed objects slide past each other.

Viscoelasticity

A property of a material expressed by a changing stress-strain relationship over time.

Relative Reference Frame

A reference frame whose origin is fixed within a moving body or segment under observation, also known as a local or cardinal reference frame.

Global Reference Frame

A reference frame whose origin is fixed at a motionless point in the environment, also known as an absolute or Newtonian reference frame.

Work

A measure of energy flow calculated as force times distance ($W = F \times d$) or torque times angular displacement ($W = M \times \Delta \Theta$), measured in Joules ($\text{J}$).