Structural Organization
434
What is the formula we use to determine muscle torque?
Tm = Fm x d
*d should denote moment arm - could not input the symbol into jeopardy!
The force a muscle is able to produce is directly dependent on what?
the length of the muscle at that point in time
The ability for a muscle to return to its normal resting length following a stretch is know as what property?
Elasticity
What is an isometric contraction?
A contraction that produces a force but no movement
What is considered the functional unit of the neuromuscular system?
Motor Unit
What are two factors that muscular strength is dependent on?
muscle length (joint angle) and muscle velocity (joint velocity)
At what muscle length do we have maximum overlap of actin-myosin?
resting muscle length
What is the extensibility property of the musculotendinouse unit?
the ability to be stretched or increase in length
What is an antagonist muscle?
A muscle whose activation produces an acceleration in a direction opposite than that required for a movement
What are the two ways in which muscle fibres can be organized?
parallel (fusiform) fibre arrangement and pennate fibre arrangement
What are the two directional components of muscle force?
rotary component and stabilizing/dislocating component
During a concentric contraction, the faster a muscle shortens, is the force developed greater or lower?
lower
What property gives muscle the ability to respond to a stimulus?
Irritability
Muscular power is the rate of _____________________.
torque production at a joint
Which type of muscle fibres reach peak tension and relax more quickly?
fast twitch fibres
What is the rotary component of muscle force?
the force the is perpendicular to the bone causing torque around the joint
What is passive insufficiency of muscles?
restriction of joint range of motion when muscles are fully stretched
Elastic tissues store _________ which is then released along with the force produced by the contractile component during concentric contraction
potential energy
Muscular power is the product of muscular force and __________
the velocity of the muscle shortnening
What is the main con regarding pennate fibre arrangement?
Not all force is developed in line with the tendon
What are the two factors that muscular strength is derived from?
• the amount of tension the muscle can generate
• the moment arms of contributing muscles with respect to a joint center
What are the two sources of force production that are added to understand the measured force output?
• Force output of the contractile component fibre length dependent
• passive elastic structures get stretched as the muscle increases in length
What is the stretch-shortening cycle?
an eccentric contraction followed immediately by concentric contraction
muscle cross-sectional area and training state of the muscle