Getting back in the groove

Last night I walked a mile on my treadmill, which was much harder than walking on the sidewalk. It kept my pulse rate up the whole time, which is very good, but I could only manage a mile the first time, instead of my usual mile and a half or more. Tonight, I went to aikido for the first time in a month. My back felt pretty good before class, and feels great now. I only managed about half the class, though. It's amazing how quickly my stamina disappears.