MUSCLE MECHANICS TERMS Flashcards
a muscle that is known to be the principle mover or one of the principle movers of a lever
Agonist:
a muscle that in contracting tends to produce movement opposite to that of an agonist
Antagonist:
the bodies sense of position of its own parts
Proprioception:
receptor located in muscle, tendons and joints that respond to mechanical changes within the body
Proprioceptor:
muscle develops tension without changing length
Isometric contraction
muscle changes length during contraction keeping tension near constant
Isotonic contraction
occurs when a muscle develops sufficient tension to overcome resistance and shortens
Concentric contraction
occurs when resistance is not overcome, but the muscle lengthens during the action
Eccentric contraction
appear redder due to an increased amount of myoglobin present
Red muscles
adapted to performing fast contractions
White muscles
muscles having a larger moving component
Spurt muscles
muscles having a larger stabilizing component than moving component
Shunt muscles
Muscles relative to joints?
The lever arm in this situation stays the same throughout the motion
▪ See a change in length of the muscle altering the proximity of the origin to the insertion (insertion brought closer to origin)
Single joint muscles
Muscles relative to joints?
Muscle will be maintained at or near its resting length, no change in the distance of origin to insertion
▪ However, the effective lever arm will change in this situation
Multi joint Muscle
Mechanical efficiency?
Mechanical efficiency will be greater if the arrangement is a 3rd class lever
Long resistance arm and short effort arm magnify speed
More movement obtained with less muscle shortening increasing efficiency of contraction
Lever arm
Mechanical efficiency?
The higher the angle of application of the muscle pull, the more efficient the contraction will be
Will see greater distance of movement of body part with a minimal amount of contraction
Angle of application
Mechanical efficiency?
Multiple joint muscles are more efficient than single joint muscles
They act at each joint they pass over, with each joint acting as a pulley
Pulley
name this example of elastic response
- At the end of midstance, the gastroc is stretched, eliciting the elastic response
- Contraction of the muscle lifts the heel and plantarflexes the foot
Gastrocnemius
name this example of elastic response
- As the leg rotates the fibula moves in relation to the tibia
- This motion applies a stretch to the syndesmotic ligament between the two bones
Tibio-fibular syndesmosis
name this example of elastic response
• When stretched during pronation, or decrease of the medial arch height, will elicit the elastic response and muscles
that supinate the foot will counteract the pronation
Spring ligament (AKA inferior calcaneonavicular ligament)
name this example of elastic response
• When elastic response is elicited it promotes muscles to rotate these portions in opposite directions
Upper trunk in gait rotates opposite of the lower trunk
When a muscle is stretched or contracted, at a certain point the tension capacity of the muscle slowly decreases
resting length
name this curve?
▪ When muscle is at its normal physiological length or resting length, it is capable of
developing maximum tension
▪ Normal physiological length is roughly 50% of the length of the muscle
Blix curve
