Research proposals are quite idiosynchratic documents. A general approach is not the way to go. You should communicate directly to your lecturers and find out their expectations are. Remember students make money for universities so you are a customer. Ask for the service you need.

Definitely don't follow a general academic essay format. The document is usually not lengthy but rather is very to-the-point and answers succinctly all the questions required. The proposal should be a blue print for your research project. A researcher who read your proposal should know exactly what you will be doing in your research. When a good proposal is written you have basically all the key material that would appear in an article up to the half-way point

Intro - all the main points but often quite truncated. It should include your the problem you are trying to solve, a critical of the literature to date that addresses the area of concern and where it fails to address this, and your aim
Methods - exactly as you would write up your article at the end
Then there will be other sections not in the article such as your timeline (GANTT chart is good), resources (use of statistician, supervisors etc), budget
Then have your reference list

I suggest you have a good look at some physio-specific research texts.

I find this one good but there are others:

Portney, L. G., & Watkins, M. P. (2000). Foundations of clinical research: Applications to practice 2nd ed. Upper Saddle River, N.J.: Prentice Hall Health.

You may be expected to write a formal proposal but also present your proposal to a group of researchers. In which case you will need to prepare a powerpoint presentation to go with it. If you haven't presented at a conference before there are a number of rules to follow and either your lecturer or from textbooks, readings etc you should study those.

And the last thing - DON'T use one of these essay writing services. It is unethical, for starters and just plain sleazy. You are there to learn the tools of a trade not employ someone to do your work for you. If you want to get top marks earn them legitimately. And I can guarantee that if your academics are good at their job (and they should be if you want a bona fide degree) that if you try cheating with one of these services they will most likely catch you out. The penalties for not submitting original (plagiarism) work can be quite severe. I have had students do this and it is as obvious as hell that they got someone else to do it. This fits under the definition of plagiarism even though these services claim they don't plagiarise. Well they probably don't. It is you who is plagiarising using some else's work