Sad to say, I ended up having to tap out in the final week. So close, but not quite. As I was racking the bar after a Zercher squat early in a workout I felt and heard something pop in my upper chest near my armpit. It didn't hurt bad; in fact after considering the risk I went ahead and completed that workout. I did find though that each swing caused some irritation, as did other movements that put any strain on my chest or arm. Much as I want to grind through it and complete the challenge, I have to look at the big picture and not make a minor injury worse by being stupid. I have way too many other things to do to be sidelined with any serious problems. So, completion of the challenge will elude me this time as I rehab, but I will do it again sometime in the future when it fits into my plans.
That said, a few final observations:
I lost a total of six pounds while doing the swings, and my abs - while still not impressive - are definitely more visible. My hands feel great and my grip endurance improved substantially. I am having a little trouble with an achy elbow tendon, but I don't know if that is because of high-rep swings, chinups, lots of shoveling snow, or (most likely) the combination of all of the above. My hamstrings are tighter now, requiring more stretching, but actually feel more muscular than when I began. I'm eager to see if all those hip hinges make a difference with my deadlifting when I resume regular strength training.
While disappointed about the way it ended, I'm glad I attempted the challenge. It was good for me both mentally and physically. I will probably revisit it next year, but in late spring or early summer instead of the dead of winter.