agonist/prime mover
the muscle that provides the primary force driving the action
antagonist
the muscle that counteracts the agonist lengthening when the agonist muscle contracts
synergist
muscles that assist in this action
orgin
where the muscle attaches to the more stationary of the bones of the axial skeleton
insertion
the point where the muscle attaches to the bone that is moved most
concentric
muscle fibres shorten
isometric
contraction: muscle fibres do not change length (static)
eccentric
muscle fibres lengthen