Muscle Mechanics Flashcards
Adverse effects of stretching only occur when the stretch is held for longer than
45 sec
What are the acute effects of stretching?
decreased strength, power, speed and movement performance=bad
pre-exercise stretching is OK is it lasts less than
30 sec
What is the stretch reflex (muscle spindle)
contraction in response to quick stretch
What is autogenic inhibition (golgi tendon organ)
immediate inhibition of muscle following contraction
What is reciprocal inhibition (muscle spindle)
inhibition of antagonist muscle during agonist contraction
Both Length tension and Force velocity assume a single muscle fiber maximally stimulated. what is the difference regarding assumptions
LT - held at a constant length (isometric)
FV - Load is held constant (isotonic) while allowed to shorten or forcibly lengthened
What are the effects of aging on skeletal tissue
increased intermuscular adipose tissue
lower neuromuscular activation
properties of single fibers preserved despite reductions in whole muscle CSA
selective atrophy of TYPE II fibers
You lose 1% of muscle mass per year after age
40
after the age of 40 muscle strength decreases___ as fast
3X
T or F Exercise can reverse the effects of aging on skeletal muscle
F. it can slow but not reverse
Regarding propulsive energy, which generates more, mono or bi-articulate muscles?
Mono
What do bi-articulate muscles allow for?
1- power transfer between joints (net transfer from proximal to distal)
2-efficient conversion of energy into desired movements
Multi-joint muscle is unable to contract forcefully in a _____ position
shortened. think forceful fist in wrist flexion
what is active insufficiency
decreased tension as length is insufficient (resting length)
when a multi-joint muscle is unable to be stretched sufficiently to produce a full range of motion in all the joints simultaneously
passive insufficiency
example of passive insufficiency
finger flexion while in wrist flexion
What is the role of bi-articular muscles for a uni-articular motion?
role shifts to coordination of movement
What is good about stretching?
Increases range of motion
decreases musculotendinous stiffness
A tendon is considered to be a _____ component in the biomechanical muscle model
series elastic
According to the Lieber article, the eccentric slide of the force-velocity curve tells us muscles are resistant to lengthening. The functional reason for this is
it allows muscles to serve as brakes and to absorb momentum which allows for controlled movement
The Henneman size principle states that
small motor neurons are recruited before large neurons to allow smooth and controlled force development
According to the concentric slide of the force velocity curve, as contraction velocity increases,
tension development decreases
