I fought a Grizzly Bear with one arm tied behind back

Yesterday my brother turned up from Cyprus, where he now lives. He was wearing horns and a tail and dragged my off to the Ben Lomond Hotel in Jarrow, the town of our birth. There we found a beautiful cask of the Old Speckled Hen and we set to work to empty it. After about the sixth pint, I was "feeling no pain" (as we used to say in my seafaring days) and I remember very little of further proceedings.
What I do remember is that, glancing round the bar, I saw many of my contemporaries, blokes who had been real tough guys when I was at school, the sort who used to take your marbles off you. They were all knacked, hollow-chested, coughing, and walking with sticks. I felt that I could wrap them all up single-handedly (the beer was talking to me). Fortunately, I didn't try, otherwise I suspect that I would be writing this from hospital.
By the way, the headline is from an old Mad magazine and the article began:
"How the devil it got its arm tied behind its back I don't know......etc, etc, etc".