insertion where most contraction occurs. contraction pulls towards the origin

origin where it starts, insertion where it ends

agonist - “prime mover”

antagonist - goes against the muscle doing the work (agonist)

synergist - “helper muscles”

relationship of muscle depends on action of muscle

bones act as levers

lever

1. fulcrum

2. resistance

3. applied force

3 classes of levers:

1. first class lever (seesaw; fulcrum in the middle of resistance and applied force)

   1. ex: neck

2. second class lever (wheelbarrow; resistance in the middle. fulcrum on one side and applied force on the other)

   1. more common

   2. ex: standing (toes fulcrum, body weight resistance, applied force is gastrocnemius and soleus via calcaneus)

3. third class lever (kitchen tongs, applied force in the middle)

   1. most common in the body

   2. fulcrum is elbow,