[tomp]

I'm not talking about force, but about energy. To hold something suspended in air, you don't need any energy. But a steel wire can't lift anything, you need to have a motor (or muscle) that actually expends energy to move the object higher.

[keenerd]

A steel wire can lift things all by itself. Just cool the wire. If you disagree with this, consider the motor or hydraulic cylinder that can't lift anything either. (Without an external source of energy like a battery or compressor.)

I'm half serious about this. The other main "artificial muscle" technology is nichrome wire after all.