I enlisted more than a decade ago, maybe things have changed but I would like to share my experience.
I experienced a lot of knee pain during BMT, usually after runs or SOCs, route march OK. Don't know why painfully but heck care. Usually can endure thru because of the "it is in the mind" attitude I went through BMT and did pretty OK. I got into Sispec (SAFINCOS in those days) and during the Sispec FFI, I told them I am "prefectly OK" without any pain. Now the reason I didn't tell them of my knee pain is because:
a. I want to sign-on pilot, have passed the medical and psychomotor tests and is going for the interview soon.
b. Even if don't sign on, I want to gungho and although disappointed didn't go OCS but would like to be section leader or maybe do went in Sispec and then go OCS.
Basically I don't want to "risk" any of the above.... so I tell them NO pain. But at SAFINCOS then siong...
Day One (Mon)
Collect Kit (last time personal eqpt not issued) and bunks.
Day Two (Tue)
5am 5BXmorning run. after morning run, breakfast and after breakfast show us SAFTI and 2.4 route, which means run around SAFTI then run to the 2.4 start point, run 2.4 then run back to Company Line.
Day three
5BX followed by morning run, breakfast, then show us SOC route, run to SOC start point and then run the SOC route in vest and slacks, afternoon PT. By then my knee cannot tahan liao.
Day Four
5BX morning run, then after breakfast endurance run (forget how many clicks). I dropped out because cannot knee tahan. later on cannot even climb the stairs.
Day Five (Friday)
Morning difficulty putting on slacks because cannot stand on one leg, have to put on slacks sitting down on the floor. Report Sick and you know what the sicko MO did, he give me Sickbay until Sunday afternoon, which means that I can't book out with the rest on Saturday monring. and Basically all those who report Sick without outward visible signs (like swelling), got about half a platoon of us from various Companies, all kana confinement in the sickbay.
The MO doesn't believe that my knee can be so serious (I cannot stand on one leg) in such a short time(4 days), I told him I got history of pain in BMT and he said your FFI says you are OK!!! So I lan lan kanna Confinement.
Cut the story short, I went to see a specialist and realised that my leg is seriously injured, downgrade to Pes E. So here ends my dream of pilot and section leader.
Moral of the story is Take heed, take care of yourself in NS.
Even then, as a Pes E clerk got best serviceman of the month twice.

Thanks for reading my story.