Chapter 8 - exam

ative insufficiency

is reached when the muscle becomes shortened to the point that it can not generate or maintain active tension -the muscle cannot shorten any farther

what is passively insufficiency

is reached when the opposing muscle becomes stretched to the point where it can no longer lengthen and allow movement

What are antagonist muscles

located on opposite side of joint from agonist -so they produce opposite joint movements to agonists AKA contralateral muscles Function: is to relax and allow agonist muscle to produce movement

What are stabilizers?

surrounds joint or body part -contract to fixate or stabilize the area to enable body segment to produce movement -establishes a firm base for the distal joints to carry out movements AKA fixators Ex: biceps curl **muscles of scapula and glenohumeral joint maintain shoulder complex in a relatively static position for the biceps brachii to more effectively perform curls

When concentrically contracting quadriceps to simultaneously cause hip flexion and knee extension, no further hip flexion and knee extension is achieved beyond a certain range of motion. This occurs because of the A. Passive insufficiency of the quadriceps B. Active insufficiency of the quadriceps C. Active insufficiency of the hip extensors D.None of the above

Active insufficiency of the quadriceps

Biceps brachii perform elbow flexion and forearm supination. When only supination action of biceps brachii is desired, the triceps brachii contracts to neutralize the flexion action of the biceps brachii. Here, triceps is working as a Stabilizer Neutralizer Antagonist Agonist

Neutralizer

What are neutralizers

counteract or neutralize action of another muscle to prevent undesirable movements contract to resist specific actions

biarticular muscles

does not actually shorten at one joint and lengthen at the other -concentric shortening of the muscle to move one joint Is offset by the motion of the other joint which moves its attachment of the muscle farther away -the maintenance of a relatively constant length results in the muscle being able to continue its exertion of force

give an example of biarticular muscles

ex:

What are force couples

force couple occur when 2 or more forces are pulling in different directions on an object causing the object to rotate about its axis -helps to have more efficient movements Ex; turning a steering wheel

What are synergists?

Assist agonist muscles AKA guiding muscles function : is to assist in refined movement EX; brachioradialis is synergist to bicep brachiii and brachialis

What are multiarticular muscles

act on three or more joints between their origin and insertion crossing multiple joints -principles relative to biarticular muscles apply similarly to multiarticular muscles ex; finger flexors

What are the different types of muscle roles

agonists, antagonists, stabilizers, synergists, neutralizers

What is the muscle roles supposed to do

movement is the result of multiple muscles working together in one or the other role

What are biarticular muscles?

muscles cross and act on two different joints Ex; quadricep muscles two advantaged over uniarticular muscles -cause and or control motion at more than one joint -maintain a relatively constant length due to shortening at one joint and lengthening at another joint

What are agonist muscles

muscles that cause joint motion aka prime movers -movement can have multiple agonists ex; elbow flexors, biceps brachii, brachialis -may produce concentric or eccentric contraction ex; biceps curl, biceps brachii is the agonist muscle work concentrically during elbow flexion work eccentrically during elbow extension

What are uniarticular muscles?

muscles that cross and act directly only on the joint that they cross EX; brachialis can only pull the humerus and ulna closer together