i think the short answer is that we shake when we are loaded with dopamine for any reason, and our motorskills are bound to display our unease. that's not a bad thing! its something to pay attention to mainly because our limits are displaid this way. if you're having trouble controling those symptoms, many places will give you remedies. breathing is always a reliable fallback, as are homeopathic remedies, and many DOMs can help you through any short spell of fear from incidents such as public speaking, etc.