As a representative of M.U.S.C.L.E.,
I find artificial muscles a bit unseemly. However, researchers at Duke
University have been able to grow their own twitching tissue, a first
that could allow researchers to test drugs on working muscle without
damaging a live host.
From the release:
From the release:

In a laboratory first, Duke researchers have grown human skeletal
muscle that contracts and responds just like native tissue to external
stimuli such as electrical pulses, biochemical signals and
pharmaceuticals.”The beauty of this work is that it can serve as a test
bed for clinical trials in a dish,” said Bursac. “We are working to test
drugs’ efficacy and safety without jeopardizing a patient’s health and
also to reproduce the functional and biochemical signals of diseases —
especially rare ones and those that make taking muscle biopsies
difficult.”
Interestingly there is no mention here of using these tiny bits of
working muscle – muscle that twitches in response to electricity and
responds to drugs just like regular human muscle – as replacements for
lost musculature, which suggests the samples are still too small to be
useful. However, this is the first time human-equivalent muscle has been
grown in the lab and it looks like it will be a real boon for
researchers trying to figure out the effects of various diseases and
drugs on the body. That said, I fully intend to eventually embed huge
chunks of artificial muscle into my body and walk around looking like
the Hulk.