CSCS CH 2 Biomechanics of Resistance Exercise Flashcards
Biomechanics
Focuses on the mechanisms through which the musculoskeletal components interact to create movement.
Origin
Proximal attachment (toward the center of the body)
Insertion
Distal attachment (Away from the center of the body)
Fleshy Attachment
mostly found at proximal end of muscle. Directly affixed to the bone, usually over a wide area so that force is distributed rather than localized.
Fibrous attachment
Tendon; blend into & are continuous with both the muscle sheaths & the connective tissue surrounding the bone.
Agonist
primary mover, muscle most directly involved in bringing about a movement.
antagonist
A muscle that can slow down or stop the movement
synergist
A muscle when it assists indirectly in a movement.
First-class lever
A lever for which the muscle force & resistive force act on opposite sides of the fulcrum. Elbow extension.
Fulcrum
The pivot point of a lever
Lever
A rigid or semirigid body that, when subjected to a force whose line of action does not pass through its pivot point, exerts force on any object impeding its tendency to rotate
Mechanical advantage
the ratio of the movement arm through which an applied force acts to that through which a resistance force acts
Moment arm
(Force arm, lever arm, & torque arm) The perpendicular distance from the line of action of the force to the fulcrum.
muscle force
force generated by biochemical activity, or the stretching of noncontractile tissue, that tends to draw the opposite ends of a muscle toward each other.
Resistance Force
Force generated by a source external to the body that acts contrary to the muscle force (gravity, friction, inertia)
Second-class lever
A lever for which the muscle force & resistive force act on the same side of the fulcrum, with the muscle force acting through a moment arm longer than that through which the resistance force acts, as when the calf muscles work to raise the body onto the balls of the feet.
Third-class lever
A lever for which the muscle force & resistive force act on the same side of the fulcrum, with the muscle force acting through a moment arm shorter than that through which the resistive force acts. Elbow Flexion
Torque
The degree to which a force tends to rotate an object about a specified fulcrum. Quantitatively as the magnitude of a force times the length of its movement arm.
Anatomical position
the body is erect, the arms are down at the sides & the palms force forward
Sagittal plane
Slices body into Right & Left. Ex Standing barbell curl.
Frontal Plane
Slices body into front & back. EX Standing lateral dumbbell raise.
Transverse planes
upper & lower sections. EX Dumbbell fly.
Strength
Ability to exert force, there is considerable disagreement as to how strength should be measured. Use of isometric strength testing & also isokinetic strength testing.
Acceleration
Change in velocity per unit time. According to Isaac Newton’s Second Law: Force=Mass X Acceleration
Power
Time rate of doing work. Power= work / time
Work
product of the force exerted on an object & the distance the object moves in the direction in which the force is exerted. Work = Force X Displacement.
Angular Displacement
The angle through which an object rotates
Angular velocity
The object’s rotational speed, measured in radians per second
Rotational work
work = torque X Angular displacement
Rotation Power
Power =Work / Time
Recruitment
Neural Control affects the maximal force output of a muscle by determining which & how many motor units are involved in a muscle contraction.
Rate Coding
The rate at which the motor units are fired.
Pennate muscle
has fibers that align obliquely with the tendon, creating a featherlike arrangement
Angle of pennation
defined as the angle between the muscle fibers & an imaginary line between the muscle’s organ & insertion, ) corresponds to no pennation.
Radiate
Glute Medius
Multipennate
Deltoid
Fusiform
Bicep brachii
Longitudinal
Rectus Abdominis
Bipennate
Rectus Femoris
Unipennate
Tibialis posterior
Concentric muscle action
The muscle shortens because the contractile force is greater than the resistive force EX.) swimming & cycling.
Eccentric muscle action
The muscle lengthens because the contractile force is less than the resistive force EX) An lowering phases of resistance training.
Isometric muscle action
The muscle length does not change; because the contractile force is equal to resistance force EX) wall-sit; Abs during sit-ups.
Classic Formula
The load lifted is divided by body weight to the two-thirds power, thus according for the relationship of cross-sectional area versus volume.
Weight-stack
Machine fixated, increased control over the direction & pattern of resistance.
Free-weights
Dumbbells, barbells. Less control & control pattern of resistance
Inertial force
Force applied by an object when accelerated. Barbell or weights. Can act in any direction.
Bracketing technique
Which the athlete performs the sport movement with less than normal & greater than normal resistance, is another form of acceleration training.
Friciton
The resistive force encountered when one attempts to move an object while it is press against another object
Fluid Resistance
The resistive force encountered by an object moving through a fluid (liquid or gas) or by a fluid moving past or around an object or through anopening.
Surface Drag
Friction of a fluid passing along the surface of an object
Form drag
The way in which a fluid presses against the front or rear of an object passing through it.
Lordotic
Lumbar spine position is superior to a rounded back for avoiding injury. Anterior rounding. Cervical & Lumbar.
Kyphotic
Rounding toward the back. Thoracic
Ventral
Toward the front (anterior)
Dorsal
Toward the back (posterior)
Fluid Ball
Abdominal fluids & tissue kept under pressure by tensing surrounding muscle (deep abdominal muscles & diaphragm) have been described as a fluid ball. That aids in supporting the vertebral column during resistance training.
Valsalva maneuver
The glottis is closed, this keeping air from escaping the lungs, & the muscles of the abdomen & rib cage contract, creating rigid compartments of liquid in the lower torso & air in the upper torso.
Shoulders
prone to injury during resistance training, due to both its structure & the forces to which is is subjected during a training session.
Knees
prone to injury because of its location between two long levers (the upper & lower leg)
Elbow & Wrists
primary injury involve overhead lifts. Not as prevalent compared to overhead sports
