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+# Muscles Part 2
+
+## muscle tension
+
+* isotonic, movement
+	* concentric - shorten
+	* eccentric - lengthen	
+* isometric, no movement
+
+always needs nervous system input
+
+difference between stability and movement basically
+
+## Motor units and recruitment
+
+neurons that go to specific fibers
+
+motor unit - plus muscle fibers that it communicate with. allows for changing value of force used.
+
+activate muscles in rotation - so we avoid over stressing
+
+dont use till it is no longer working. just rotate so that the transitions are less jaring
+
+## Muscles rarely completly relax
+muscle tone when not flexing is because of higher muscle density
+
+hypertonia - too few recruited muscles (unable to move)
+
+hypertonia - too muchj muscle stress (unable to relax)
+
+
+## Skeletal Muscle Movement
+* form dictates function
+	* muscles are attached to bones to allow for movement
+* muscle origin - anchor point (bicept on the humerous /scapulus)
+* muscle insertion - (bicept to radius)
+
+
+you will have a chart of origin, insertion, action
+
+elbow hinge joint
+muscles are with joints
+
+## Muscles (almost) never work alone
+* aiding, opposite work together
+
+prime mover/ agonist -> main muscle moving things
+
+synergist -> assits movement
+
+antagonist -> opposite movement of agonist
+* maintains body position
+* needed for rapid movement
+
+