Two Joint Muscles Flashcards
What is the definition of a two joint muscle?
A muscle that, from origin to insertion crosses two joints, thus can produce an action at both joints.
What are the 4 characteristics of a two joint muscle?
Concurrent Action.
Countercurrent Action.
Active Insufficiency.
Passive Insufficiency.
What is meant by concurrent action?
Simultaneous flexion or extension of the hip and knee joint.
What is meant by countercurrent action?
One muscle shortens rapidly at both ends, thereby losing tension.
What is meant by active insufficiency?
When a two joint muscle contracts across both joints simultaneously and cannot produce sufficient force to complete full ROM at both joints.
Occurs at the Agonist.
What is meant by passive insufficiency?
When a two joint muscle is lengthened over both joints simultaneously, restricting full ROM at both joints it crosses.
Occurs at the Antagonist.
What is the lombards paradox?
Concerned with the act of standing from sitting.
Where the agonist and antagonist contract together concentrically to stand up.
