Dude you are training for adventure racing now. The official term for what you did is hike-a-bike
Next time bricks in the back-pack?
some ratty AR'ers did that to me once. Put rocks in ny backpack while I was not near it. Probably about 10 pounds. I did not notice till I got home.
so called friends. Making sure that I got a solid workout!
good for them. good for you.
I have to say it was not a bad experience