After a week's absence, today's return was sweltering despite the A/C (!) which Sensei decided to turn on. The main thing I noticed after was fatigue in my abs, which I hope is due to my greater use of my tanden and so on. It could just be the heat, though. The daily 5-minute plank routine has worked wonders--forward, side, side, back, forward, at 60 seconds each. One of those things where you don't get faster when you get better...