Section 2: Muscle Mechanics Lec 2-1 Flashcards
Ft
total force
Fc
contraction force
Fp
passive force
l0
length for greatest tension
isometric contraction
no shortening of the sarcomere
force is dependent on
of crossbridges (muscle, fiber, myofibril)
species differences in sarcomere length at peak tension due to :
myosin: length is constant at ~1.6 microm
actin: frog .95 microm
actin: human 1.27 micrometers
true or false: mammals are able to generate force over larger ranges of sarcomere lengths than the frog
true
parallel elastic (PE) elements
connective tissue surrounding contractile elements
series elastic (SE) elements
connective tissue in series with contractile elements (tendon, sarcomeres, titon, nebulin)
summation
-increasing force due to increased frequency of stimulation
summation is due to
decreased time for deactivation between stimuli
-partly, but not entirely, due to slow Ca++ ATPase
tension=
F(muscle/sarcomere length)/ # of crossbridges
**this is true for twitch, submax, and MVC
isotonic contraction
constant load, muscle allowed to shorten
slope
distance/time or velocity of contraction
latency period
the time to lengthen the series elastic elements until tension equals load to be lifted
power
work/time or FxD/time or force x velocity
peak power occurs at _____ of peak force (Po)
30%
true or false: a small female subject performing the eccentric exercise could easily fatigue a large man
true
vO2 was significantly less for the eccentric work than for the concentric exercise. what is the equation?
VO2 concentric= 5 x VO2 eccentric
eccentric contractions
lengthening of muscle while it is activated to contract
F external > F muscle
force» peak isometric force
what does the force response suggest?
muscle is very resistant to lengthening
velocity reponse
has almost no effect on force
Much of daily movement is a combination of _____ and ______ contractions
concentric and eccentric contractions