Chapter 4: Biomechanics Flashcards
Lever
A simple machine that has a rigid bar rotating around a point of rotation in order to multiply the effect of mechanical force or increase the distance force is applied.
Fulcrum
The point of rotation
Lever arm
The distance through which force is applied.
Sticking point
The hardest point of the lift
Law of Inertia Linear Movement
An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction (velocity) unless acted on by an external force.
Law of Inertia Angular Movement
An object will maintain a constant angular velocity unless acted on by an external torque (moment).
Law of Inertia
The resistance of an object to change its state of motion.
Law of Acceleration
The Law of Acceleration forms the basis of quantifying training load.
Law of Acceleration Formula
F = m * a
Law of Acceleration Linear Movement
The linear acceleration of an object is produced by a force directly proportional to that force and inversely proportional to the object’s mass.
Law of Acceleration Angular Movement
The angular acceleration of an object is produced by a torque (moment) directly proportional to that torque and inversely proportional to the object’s moment of inertia.
Law of Reaction Linear Movement
For every force, there is a reaction force equal in magnitude and opposite in direction.
Law of Reaction Angular Movement
For every torque (moment), there is a reaction torque (moment) equal in magnitude and opposite in direction
Inertia
The resistance an object has
Magnitude
The size referred to in a vector quantity
Torque
The rotational effect of a force
Mechanical Work equation
W = F X d, force times distance
Angular work equation
Angular moment multiplied by angular displacement
Positive work
The motive force and the movement direction are both the same.
Negative work
The motive force and the movement direction are opposite.
Power equation
Work divided by time
Power
The rate at which force can be produced
Antalgic gait abnormality
A self-protective result of injury to the pelvis, hip, knee, ankle, or foot
Arthrogenic gait abnormality
Results from stiffness, laxity, or deformity
Equinis gait abnormality
Inadequate dorsiflexion range
Shot leg gait abnormality
Leg length difference
Biomechanics
The branch of science that applies the mechanics’ principles to living organisms
Total Caloric Expenditure
Metabolic measure of the volume of activity a person has completed.
Active muscle force
The muscular contraction force created through the sliding filament theory.
Passive muscle force
Passive refers to the fact that this force is generated not by the muscle itsell but by the application of an outside force to prestretch the muscle.
Biomechanics response to the Antalgic gait
Stance phases of two limbs are not equal in time.
Biomechanics response to the Arthrogenic gait
Unequal step lengths of the two limbs and circumduction of the affected limb.
Biomechanics response to the Equinus gait
-Weight bearing on lateral edge of the foot
-Decreased stance time on affected side
-Pelvis and femur may be laterally rotated
Biomechanics response to the Short leg gait
-Pelvic obliquity
-Exaggerated flexion of knee and hip of unaffected limb
-Hip “hiking” during swing phase for foot clearance
-Transverse plane movement of arm on one side
Biomechanics
A discipline of science that combines physiology and physics in an effort to apply the laws of physics to living organisms.
