Muscular system in blender I would like to know if there is a tool or an addon in Blender that can help me to create a muscular system, i.e. a way to move the mesh (like the contraction of biceps).

I was watching this video but I'm not sure how well it works.

Any advice or should i use shape keys?
Do you need muscle jiggle? Thats the real question.

If yes you have to use softbody simulation. The Muscle Tools plugin is imho not very helpful, because it treats the muscles one by one and not like a whole muscular system. Here is how I would setup that: 

How do you assign multiple shrinkwrap modifiers to rig muscles?.

If you don't need muscle jiggle than the simulation and shrinkwrap is just overcomplication and you can use bones and shapekeys to do everything. In that regard you can also use stretch maps and lattices for skin sliding.