Most dielectric elastomer actuators are in the shape of stacked sheets or rolled sheets of conductive and dielectric materials.
If the dielectric elastomers were parallel/enroled fibers with a dielectric layer with the same charge, wouldn't the fibers repel each other and simulate a muscular contraction?
I don't even know if this is limited to electrostatic charges, nor limited to elastomers. Maybe you could make these fibers using flexible but not elastic materials such as polymers.