Dr. Karius Contraction 2 Flashcards
during isotonic contraction, the thin and thick filaments
overlap one another
during isotonic contraction the muscle
gets shorter
during isotonic contraction
the torque of the muscle has to increase
isometric
muscle contraction without movement
push against a wall as an example: the wall isn’t going anywhere but there is muscle contraction
muscle remains same length.
cross bridge cycles but no change in length. there is an increase in tension/force
isotonic
when muscle contracts and there IS movement
same tone
cross bridge cycle shortens muscle length
there is no change in tension force
Cross bridge cycling….slowly
isometric
cross bridge changes: isotonic
does occur
ATP required for isometric and isotonic?
yes for both
shortening of muscles during isometric contraction
very very little
shortening of muscles during isotonic contraction
yes
How much “force” development does isometric contraction have?
maximal
how much “force development” does isotonic contraction have
none
does isometric have ANY shortening?
yes but very little.
why is there some shortening during isometric contraction?
series elastic element: the tendons (elastic) and other tissues in series with the muscle that get shorter, because these tissues are elastic so they can get shorter
they are stretched by the contraction
essentially they are the slack that muscle contraction “takes up”
the first event that happens when you pick up weight it
actually a series elastic element
the first event that happens when you pick up weight it
actually a series elastic element
the first event that happens when you pick up weight it
actually a series elastic element
the first event that happens when you pick up weight it
actually a series elastic element
the first event that happens when you pick up weight it
actually a series elastic element
the first event that happens when you pick up weight it
actually a series elastic element
the first event that happens when you pick up weight it
actually a series elastic element
does isometric contraction happen during isotonic motion?
yes, all motion is a combination of isometric and isotonic
what is the first stage of lifting something?
stretch series element (isometric) STRETCH
what is the second stage of lifting something?
generates the force: isometric contraction GENERATE FORCE
what is the third stage of lifting something?
isotonic contraction “lifting” LIFT
things that change muscle contraction
the length of the muscle
how much weights the muscle is trying to move (the “load”)
when the muscle is affected by the weight
Force is proportional to
the number of cross bridge heads (how many are cycling)
at normal resting, the muscle is at
ideal length for generating contraction
maximal cross bridge cycling occurs during
rest
when is there less than maximal cross bridge cycling?
during contraction, shortening or lengthening
a muscle that is too long will have
less cross bridge cycling and less tension
tension would be least when the muscle
is at it’s maximal length
a muscle that is too short will effect the cross bridges how?
the myosin heads have no actin to bind
tension decrease when the muscle
is too short or too long
how much passive tension do you have during a shortening length of muscle
none
when does passive tension begin to occur?
during muscle lengthening
passive tension -
the tendon being stretched
passive tension and active tension
sum together ro peosuxw “TOTAL TENSION”
Active tension declines when
there are no more cross bridges
occurs when muscle is too long or too short
active tension =
what cross bridges can do
passive tension is the “blank…“effect
rubber band effect
preload
the effect the load has on the muscle prior to contraction
afterload
the weight has been transferred to something else
why doesnt the load force on a diagram ever go to zero?
your muscles have to move themselves
if the muscle is stretched prior to contraction, what kind of load is it?
pre-load
if the muscle is not stretched prior to contraction, what kind of load is it?
after load
muscle too short
too much overlap = thick filaments are in the way of thin filaments = less tension
Afterload: effect at the start of contraction
more time spent in isometric contraction for force generation
Preload: effect at the start of contraction
decreased active tension due to stretch
