There are other systems like chemical, memory metal and the like, but they are not developed to the point where I want to experiment with them at this time. Assuming we start with a central power plant, we must plumb power with some sort of distribution system. The most popular choices at this time are fluid power, cables, push rods, and rotary shafts. I am partial to air because it does not leak all over the floor. And let's not forget there is lots of it around.
Lets work up a system using air power and see what falls out.
There are lots of devices to transform pressure into movement. I am intrigued with the woven tubing muscle I thought of. I will have to experiment with some of these and see if they offer any real advantages. Lets assume that the leg muscles are the strongest muscles in our robot. The leg muscle will have to lift the entire weight of the robot and load.