132 ch 12 BioMechanics
Kinetics
Study of forces (such as gravity, friction and pressure) that act on the body to generate or alter motion.
moment arm
ØA __ is simply the length between a joint axis and the line of force acting on that joint.
1. A nerve plexus is a group of intersecting nerves composed of afferent and efferent fibers. 2. Four 3. Cervical, Brachial, Lumbar, Sacral
1. Define nerve plexus 2. How many are there in the human body? 3. Name them
Force
: Any influence that causes an object to undergo a certain change.
Biomechanics
: The mechanical principles that directly relate to the body.
Friction
A force that resists the relative motion of two surfaces.
Vector
A force with direction and magnitude. All forces are vectors, Including muscle forces.
Law of Inertia
An object at rest tends to stay at rest, while an object in motion tends to stay in motion unless acted upon by an outside force is:
Inertia
An object's resistance to a change in its state of motion or rest. Newton's first law of motion - sometimes referred to as the law of inertia. An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
Inertia
An object's resistance to a change in its state of motion or rest:
Force
Any influence that causes an object to undergo a certain change.
Concurrent force
Concurrent forces occur when two or more forces connect at a common point but pull in divergent directions. Together the gluteus medius's three sections produce a resultant force - The net result of two or more different forces.
Dynamics
Deals with aspects of moving systems. It focuses on your "dynamic body" - one that changes shape at an appreciable rate - and how various forces affect it.
Statics
Deals with aspects of nonmoving (or virtually nonmoving systems).
Reciprocal Inhibition is the neurological reflex that relaxes one muscle when its opposing muscle contracts. That is, the neurological reflex when the antagonist relaxes while the agonist contracts.
Define Reciprocal inhibition
moment arm
Every joint that is involved in an exercise has a
Arthrokinematics
Focuses on the motion that occurs between the articulating surfaces of joints. (roll, spin, glide)
Torque
Force that involves rotation of an object about (around) an axis; it is force with a twist.
Parallel force -
Forces acting on the same plane, aligned with each other.
ØLaw of Acceleration:
Newton's Second Law of Motion states that the acceleration of an object is directly proportional to the force acting on it and is inversely proportional to its mass. The direction of the acceleration is the direction of the applied force.
ØLaw of Action-Reaction:
Newton's Third Law of Motion states that for every action there is an equal and opposite reaction.
Linear force - When all forces occur along the same line of action. Parallel force - Forces acting on the same plane, aligned with each other. Concurrent force - When two or more forces connect at a common point, but pull in divergent directions.
Not all forces are the same, and they can be divided into three systems, name and define them:
Kinematics
The analysis of movement in terms of mechanical aspects (such as time, space, and mass).
Gravity
The force that attracts a body toward the center of the earth.
moment arm
The longer the __ is the more load will be applied to the joint axis through leverage.
Leverage
The mechanical advantage of a force to move an object:
resultant force -
The net result of two or more different forces.
Osteokinematics
The pathway of moving bones.
Momentum
The product of mass and velocity
Mass
The quantity of matter in an object. The more mass an object possesses, the greater its resistance to change.
Velocity
The rate of change of a position; speed plus direction.
Righting reflex
What is the involuntary response that directs muscles below the cranium to shift the body however necessary to keep the head plumb and the eyes level with the horizon?
Acceleration
What is the rate at which the velocity of a body [object] changes with time?
Linear force -
When all forces occur along the same line of action.
Linear force
When all forces occur along the same line of action. (Remember line of pull?)
Concurrent force -
When two or more forces connect at a common point, but pull in divergent directions.
Muscle spindle cells
Which proprioceptor monitors the stretch of a muscle and its rate of change?
Torque
_____: A force that involves rotation of an object around an axis.
Friction
_____: A force that resists the relative motion of two surfaces.
Vector
_____: A force with direction and magnitude
Velocity
_____: An object's rate of change of its position.
Inertia
_____: An objects resistance to change in its state of motion or rest.
Force
_____: Any influence that causes an object to undergo a certain change.
Kinematics
_____: The analysis of movement in terms of mechanical elements.
Momentum
_____: The product of mass and velocity.
Parallel force
act on the same plane and are aligned with each other. They can move in the same or opposite directions. When such forces move in opposite directions, they produce a rotary force known as a force couple. (Think of a steering wheel)
Newton's First Law of Motion states that an object at rest tends to stay at rest, while an object in motion tends to stay in motion unless acted upon by an equal or opposite force; that is, an unbalancing force.
ØLaw of Inertia:
a change in direction, a change in movement, or a change in structure.
( Force)That change might transpire in one of three ways: Whether you are in motion or at rest, forces either affect your tissues from the outside of your body or emanate from inside of your body.
Moment arm
The perpendicular distance from the muscle's line of action to the axis of rotation.
Velocity
Rate of change of position
ØThe amount of force exerted ØThe distance from the force to the axis
ØTorque: A force that involves rotation of an object about (around) an axis. Rotary motion depends on two critical factors: