I have been reading more on earthing today and found another interesting article. The author links all types of bodywork into a common thread, effectively saying that all these therapies have some effect because you have one person touching another. During this touch, there is a transfer of electrons into the inflamed area which promotes healing. This is the same process used in barefoot contact with the earth, where electrical charges are received by the body.
Therefore, any type of touching may work for acute injuries. There may not be any magic in one type of bodywork versus another. Putting science to the side, I would just take on faith that touching leads to healing. It is a natural human reaction to touch someone we care about when they are injured.
This may show why the changes from bodywork may not "stick" for long-term or chronic conditions. If you have a chronic injury, then you get some bodywork and feel better temporarily due to the energy transfer. Then this transferred energy dissipates and the problem returns.
From the author's point of view, the long-term solution would be to use grounding on a daily basis to provide a constant flow of energy. This can be done by barefoot contact with the ground or the use of things like a "grounding mattress pad" (that effectively grounds a bed to the earth).
I hope this post doesn't read like science fiction. I am as skeptical as anyone, but this theory is really just another aspect of Paleolithic health.