It is not necessary to get the medical done before or at the time of application. It can be done upfront, if you want, but it is not necessary. Only health insurance need to be attached at the time of application. Once you submit the application, after around a month or so, IRCC will send message to get the medical done and once that is done, the doctors will upload the report on portal.
just for your information, this was my time line for Super visa (for self and spouse):
Date of submission- December 09
Biometric collection letter - December 09
Biometrics updated - December 11
Medical request letter - January 25
Medical done - January 28
Medical passed status updated on portal - February 03
Final decision and original Passport submission request letter - February 25
Passport sent (thru 2 Way courier service) - February 27
Passport reached IRCC embassy in Delhi - March 04
Current Status (as on 31 Mar) - Application in Process by IRCC
Awaiting status update from IRCC and VFC
