ch 2 biomechanics of resistance exercise Flashcards
study of the mechanisms through which the musculoskeletal components interact to create movement
biomechanics
muscle origin
proximal attachment-toward the center of the body less mobile (anchor)
muscle insertion
distal attachment more mobile
type of attachment where muscle is directly affixed to the bone (usually at proximal attachment over a wide area)
fleshy attachment
attachments that are continuous with both the muscle sheaths and CT surrounding the bone
fibrous attachments
types of fibrous attachments
tendons, ligaments
the muscle most directly involved in bringing about movement
prime mover agonist
a muscle that can slow or stop the movement of an agonist is called…
antagonist
muscles that assist in joint stabilization and in breaking at the end of a rapid movement
antagonist
a muscle that assists indirectly in a movement
synergist
muscles that don’t act through levers
face muscles, tongue, heart
1st class lever def and draw
a lever for which the muscle force and resistive force act on opposite sides of the fulcrum

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 tendancy to rotate
mechanical advantage
the ratio of moment arm through which an applied force acts to that through which a resistive force acts
represented as a ratio of greater than 1.0 (allows the applied muscle force to be less than the resistive force to produce an equal amount of torque
mechanical advantage < 1.0
one must apply greater muscle force than the amount of resistive force present (creating a mechanica disadvantage)
moment arm (torque arm, force arm, lever arm)
the perpendicular distance from the line of action of the force to the fulcrum
muscle force
force generated by biomechanical activity or the stretching of noncontractile tissue, that tends to draw opposite ends of a muscle toward eachother
resistive force
force generated by a source external to the body (gravity,enertia,friction) that acts contrary to muscle force
second class lever def and draw
a lever for which the muscle force and resistive force act on the same side of the fulcrum with the muscle force acting on a longer fulcrum than that of the resistive force

example of a first class lever muscle
triceps
example of 2nd class lever muscle
calf muscles
the greater the mechanical advantage, the
less force needed to resist external forces
third class lever def and draw
a lever for which the muscle force and resistive force act on the same side of the fulcrum, with the muscle force acting through a moment arm shorter than that of the resistive force

torque (moment)
the degree to which a force tends to rotate an object about a specific fulcrum
the magnitude of a force times the length of its moment arm
example of a 3rd class lever system in the body
biceps
most muscles that rotate the lims about body joints opperate at a mechanical
disadvantage
internal muscle forces are much—–than the forces exerted by the body on external objects
greater
mechanical advantage changes during real world activities….give an example
biceps curle…the resistive moment arm changes throughout the movement
tendon insertion and mechanical advantage
a person whose tendons are inserted on the bone farther from the joint center shoud be able to lift heavier weights
tendons that insert farther from the joint are stronger, but they also have …
a loss of maximum speed because the muscle has to contract more to make the joint move through a given ROM
draw saggital, frontal, and transverse planes

important sports movements not usually incorporated into standard resistance training programs
internal/external shoulder rotation (throwing, tennis)
knee flexion (sprinting)
hip flexion (sprinting, kicking)
ankle dorsiflexion (running)
hip ABD, ADD (lateral cutting)
torso rotation (throwing,batting)
neck movements (boxing, wrestling)
strength def
the ability to exert force
change in velocity per unit time
acceleration
force equation
F=MA
Newton’s second law
power def
work def
the time rate of doing work
where work is defined as:
the product of the foce exerted on the object and the distance the object moved
work equation
work= force x displacement
power equation
power= work/time
force is measured in
Newtons
distance is measured in
meters
work is measured in
joules, newton-meters, or Nm
time is measured in
seconds
power is measured in
watts
when force is exerted on a weight in the direction opposite to the one in which the weight is moving (as when a weight is lowered in a controlled manner), calculated power and work ….
have a negative sign
angular displacement
the angle through which an object rotates
angular displacement is measured in
radians
1 radian (rad) =
180 degrees / pie = 57.3 degrees
angular velocity is measured in
radians per second
rad/s
equation for rotational work
work= torque x angular displacement
Strength can be slow or fast…it is the capacity to exert force at…
any given velocity
power is the
mathmatical product of force and velocity, whatever the speed.
neural control affects the maximal force output of a muscle by determining…
RECRUITMENT
which and how many motor units are involved in a muscle contraction
RATE CODING
the rate at which motor units are fired
RATE CODING
THE RATE AT WHICH MOTOR UNITES ARE FIRED
MUSCLE RECRUITMENT
WHICH AND HOW MANY MOTOR UNITES ARE RECRUITED FOR CONTRACTION
A FORCE A MUSCLE CAN EXERT IS RELATED TO ITS—-RATHER THAN TO ITS—-
CROSS SECTIONAL AREA RATHAR THAN TO ITS VOLUME
PENNATE MUSCLE FIBERS ALIGN
OBLIQUELY WITH THE TENDON
ANGLE OF PENNATION
THE ANGLE BETWEEN THE MUSCLE FIBERS AND AN IMAGINARY LINE BETWEEN THE MUSCLES ORIGIN AND INSERTION
THE ANGLE OF PENNATION—–AS THE MUSCLE SHORTENS
INCREASES
WHEN ARE THE MAXIMAL NUMBER OF CROSS BRIDGE SITES AVAILABLE?
WHEN THE MUSCLE IS AT RESTING LENGTH
THE MUSCLE CAN GENERATE ITS GREATEST FORCE AT…
RESTING LENGTH
THE FORCE CAPABILITY OF A MUSCLE DECREASES AS…
VELOCITY OF CONTRACTION INCREASES
3 TYPES OF MUSCLE ACTION
CONCENTRIC MUSCLE ACTION
ECCENTRIC MUSCLE ACTION
ISOMETRIC MUSCLE ACTION
CONCENTRIC MUSCLE ACTION
THE MUSCLE SHORTENS
BIKING AND SWIMMING INVOLVE CONCENTRIC MUSCLE ACTION ALMOST EXCLUSIVELY
ECCENTRIC MUSCLE ACTION
THE MUSCLE LENGTHENS BECAUSE CONTRACTILE FORCE IS LESS THAN RESISTIVE FORCE
LOWERING PHASE OF A RESISTANCE EXERCISE
ISOMETRIC MUSCLE CONTRACTION
THE MUSCLE LENGTH DOES NOT CHANGE BECAUSE THE CONTRACTILE FORCE IS EQUAL TO THE RESISTIVE FORCE
ISOKINETIC TRAINING
SPEED OF MOVEMENT REMAINS CONSTANT
SMALLER ATHLETES ARE —- POUND FOR POUND THAN BIGGER ATHLETES
STRONGER
CLASSIC FORMULA
COMPARES STRENGTH BETWEEN DIFFERENT WEIGHT CLASSES
LOAD LIFTED / BODY WEIGHT TO THE 2/3 POWER
MOST COMMON SOURCES OF RESISTANCE FOR STRENGTH TRAINING EXERCISES
GRAVITY
INERTIA
FRICTION
FLUID RESISTANCE
ELASTICITY
GRAVITY
THE DOWNWARD FORCE ON AN OBJECT FROM THE PULL OF GRAVITY
= OBJECT’S MASS X GRAVITY
ADVANTAGES OF WEIGHT MACHINES
SAFETY
DESIGN FLEXIBILITY
EASE OF USE
ADVANTAGES OF FREE WEIGHTS
WHOLE BODY TRAINING
SIMULATION OF REAL LIFE ACTIVITIES
INERTIAL FORCE CAN ACT IN…
ANY DIRECTION
INERTIA AND ACCELERATION PATTERN
THE AGNOIST MUSCLES PROVIDE FORCE IN ACCESS OF THE BAR WEIGHT EARLY IN THE MOVEMENT, BUT LESS THAN THE BAR WEIGHT LATE IN THE MOVEMENT
BECAUSE OF INERTIA, HEAVIER WEIGHTS CAN BE USED IN…
ACCELERATIVE EXERCISES AS COMPARED TO SLOW EXERCISES
ACCELERATION MAKES RESISTANCE PATTERNS..
LESS PREDICTABLE