If you do the research to be aware of safe and effective frequency and amplitude you will find vibration plates that are both of these, but not many. There is ONE on Amazon. VT007 Vibration Plate Exercise Machine - High Frequency, Low Amplitude | Muscles, Bones and Nerves Training | Blood and Lymph Circulation Improvement The owner has a lot of information as well as a study he is initiating. There is also a separate site with info and a similar unit for sale-- Vibrant Health. Both machines are a fraction of the cost of the Marodyne, which, while safe, is possibly not very effective for building bone at the preset vibrations. (They are doing studies, yes. ) Check these out, if only for the information. Marodyne is ridiculously expensive for what it may not even accomplish. And the Power Plates, etc on Amazon , while affordable, my cause harm.