Muscles and Engines, Alike?

In reading The Selfish Gene there was a talk in which Dawkins was comparing the speed of plants and animals and how they were faster. When talking about how animals got their speed he said, "The gadget that animals evolved to achieve rapid movement is muscle" (p. 49). In his following points I found a very interesting metaphor that compares engines to muscles. Dawkins talks about muscles and engines (talking about the steam engine) and mentions a few similarities, he says that they both use energy stored in chemical fuel to exert mechanical movement, the only difference is that when making sudden force, the muscle creates tension and the engine creates steam pressure.

I personally liked the metaphor because I had always wondered how muscles worked. People had given me very complex explanations so I just understood the basics. In my mind it wasn't clear how muscles worked and whenever I asked people wouldn't know how to fully explain how muscles worked on exerting the force. Everybody knows that muscles are the organs in the body that exert the force but nobody really knows how they do that. So I was missing this question until I read this metaphor and description.