Lesson
Muscles
Muscles can be uni– or bi- multi-articular
ie. can cross one, two or multiple joints (brachialis, biceps brachii, erector spinae)
BIARTICULAR MUSCLES need stabilizers and joint positioners http://www.lab.anhb.uwa.edu.au/hfa213/week4/lec4bimuscle.pdf
Advantage of bi- multi-articular muscles:
– only one muscle needed to generate tension at 2 or more joints
-MORE efficient, CONSERVES energy
-muscle length stays closer to resting length, as one side
shortens the other stretches (eg.rectus femoris in hip & knee extension long & short resp.)
-Muscles more effective through entire ROM of both joints
Disadvantages -Active Insufficiency(muscle cannot shorten enough for all actions)
-Passive Insufficiency(muscle cannot lengthen enough for full ROM)