CHAP 2 Flashcards
muscle can only (push/pull)
pull
3 type of joint
fibrous, cartilaginous, synovial
which moment arm is an advantage
when moment arm > 1
when does moment arm is a disadvantage
MA < 1
which moment arm favors low strength and high velocity
MA < 1
which moment arm favours high strength and low velocity
MA > 1
when does MA < 1
when FR < Fa
when does MA > 1
when Fa< Fr
isometric exertion or constant-speed joint rotation is which class of lever
1st
which class of lever occurs when the body is stationary or moving upward at a constant velocity
2nd
exemple of 2nd class lever
calf raise
exemple of 1st class lever
elbow extension against resistance
exemple of 3rd class lever
elbow flexion against resistance
which class lever occurs when the arm is stationary or moving upward at a constant velocity
3rd class lever
role of patella in mechanic of the knee
The patella increases the mechanical advantage of the quadriceps muscle group by maintaining the quadriceps tendon’s distance from the knee’s axis of rotation.
most skeletal muscle operate at a considerable mechanical (advantage/disadvantage)
disadvantage
the primary lever orientation in the human is
3rd class
human are built more for (speed/strenght) than (speed/strenght)
speed than strength
during sports and other physical activities, forces in the muscles and tendons are much (higher/lower) than those exerted by the hands or feet on external objects or the ground.
higher
tendon insertion farther from the joint center result in
ability to lift heavier, has larger moment arm = create greater torque but less rotation per unit of muscle contraction so slower movement speed -> loss of maximum speed and reduce muscle force capability during faster mvt
strength is associate with
slow speed of movement, ability to exert force at low speed
muscle force is greater when
more motor units are involved in a contraction,
the motor units are greater isze, or
the rate of firing is faster.
the force a muscle can exert is related to what
cross-sectional area rather than to its volume
what is a pennate muscle
a muscle with fibers that align obliquely with the tendon, creating a featherlike arrangement.
what is the angle of pennation
is the angle between the muscle fibers and an imaginary line between the muscle’s origin & insertion
what is most often the pinnation angle
< or equal to 15º
what happen with force generation if a muscle have CSA remaining the same but have an increase in pinnation
allows a muscle to generate a greater amount of force than nonpennate muscle.
what happen with velocity if a muscle have CSA remaining the same but have an increase in pennation
results in a lower maximal shortening velocity than nonpennate muscle
when does a muscle generate the greatest amount of force
when it is a its resting length
the amount of torque exerted depend on
the force versus muscle length relationship,
the variation in leverage attributable to the dynamic geometry of the muscles, tendons, & internal joint structures,
type of exercise,
the body joint in question,
the muscles used at that joint, and
the speed of contraction.
the force capability of muscle (decrease/increase) as the velocity of contraction (decrease/increase)
decrease, increase
as velocity of movement (decrease/increase), the max force a muscle can produce concentrically (decrease/increase)
increase, decrease
relationship btw force velocity is linear or non-linear
linear
the decline of force-velocity is steepest when speed is (increase/decrease) from
increase from slow to moderate
what is the max power a muscle
around 1/3 Vmax
a well-designed strength power training program will shift the force-velocity to the (right/left) and the power curve (downward/upward)
right, upward
during isokinetic concentric exercise torque capability (increase/decline) as angular velocity (increase/decline)
decline, increase
during which type of angular velocity torque capability declines as angular velocity increases
isokinetic concentric
during eccentric exercise maximal torque capability (increase/decline) until about 90% after which it (increase/decline) gradually
increase, decline
during which angular velocity maximal torque capability increases until about 90o/s, after which it declines gradually.
eccentric
place angular velocity in order of muscle force
eccentric > isometric >concentric
strength-to-mass ration reflect what
athlete ability to accelerate their body
Is the strength-to-mass ratio of larger athletes higher or lower than that of smaller athletes?
no, smaller athlete will have a higher strength to mass ratio
as body size (increase/decrease) body mass (increase/decrease) rapidly than the does muscle strength
increase, increase
a muscle contractile force is fairly proportional to its
csa
muscle mass is proportional to its
volume
during a free weight exercise, when the weight is horizontally closer to the joint, it exerts (more/less) resistive force
less
what happen in beggining of a barbell curl
the bar is accelerated from a zero velocity to an upward velocity.
what happen near the top of a barbell curl
there is some deceleration to bring the bar’s velocity back to zero.
what happen early in the ROM of a barbell curl
the agonist muscles receive resistance in excess of the bar weight
what happen toward the end of the ROM of a barbell curl
the agonist muscles receive resistance less than the bar weight.
coefficient of static friction is always (greater/less) than the coeffienc of sliding friction
greater
what is surface drag
Results from the friction of a fluid passing along the surface of an object.
what is form drag
Results from the way in which a fluid presses against the front or rear of an object moving through it.
fluid-resistance exercise machine allow what
Allow rapid acceleration early in the exercise movement.
Allow little acceleration after higher speeds are achieved.
which type of exercise machine Do not generally provide an eccentric exercise phase, although machines with an internal pump do.
fluid-resisted exercise machine
which type of exercise machine cannot perform isokinetic exercise
fluid-resisted exercise machine
during 3rd class lever muscle is at advantage or disadvantage and why
This is a disadvantage because a larger muscular force is required to move the resistance.
MM < MR, FM > FR .
during 2nd class lever muscle are at advantage or disadvantage
This is an advantage because a small muscular force is required to move a person’s body weight.because
MM > MR, FM < FR .
1st class lever muscle work at an advantage or disadvantage
disadvantage
