Obviously asking you to quit your job or move to another part of the world to gain entrance to med school would be absurd. But some people (which I am not saying is your case) will apply with the same app but with about 20 hours more of shadowing. That will NOT be enough to show improvement and dedication. You will have to do more shadowing, non-clinical volunteering, research, etc. in order to justify reapplying. Again, if you applied with more or less the same thing last cycle and didn't get in odds are the same app will not get you over the hump this time. I am giving you honest advice as I have come across this with applicants in the past.