Have you attempted to work with your employer to find another position which would not be as physically taxing?
You need to prove that you attempted to resolve this situation with your employer, that the situation was unresolvable, and that you are able and available to work, and quit for compelling good cause:
Quits are
always problematic. Even if you can prove you tried to work it out with your employer, can do other work, just not that job because of physical limitations, NJ may initially deny, because that is what they do whenever there is any doubt. A lot depends on the examiner. If a denial happens to you, you will wait five-six months for an appeal hearing. NJ is very slow in scheduling appeals. So be prepared to be without benefits for half a year, at least, if you quit.
Gather any correspondence and proof relative to your attempts to work with your employer. Also, of course, any medical documentation you submit should clearly show you had a compelling reason for this quit.