Not even joking.
I left home with one intention today: keep at the same heart rate throughout the entire ride. It wasn’t even a tough heart rate. Let me put it this way: if you were to keep that HR on a trainer, it would not be considered an intensity session.
So into the headwind I started, pushing against my old friend the wind, knowing I wouldn’t be done with it for at least 45 minutes. For the only mile and a half of the course where I wasn’t facing a headwind, I felt like I was flying. For the rest of the time, I felt like a chin hair dodging a razor blade. And when the turnaround came, it was blessed relief, I thought.
That is, until I looked at my heart rate monitor.
I was, once again, flying, but my HR wasn’t anywhere near where it needed to be, so I ramped up the gears a little and started to crank. Forty-five minutes later, I arrived at home, my back, quads, and particularly butt felt like I’d been clenching for the entire 45 minutes. Ouch. I felt like I’d just done a squat session at the gym. And let me tell you, the hot shower I took when I got back felt SO NICE!
So here’s my scientific conclusion: climbing, I think, results in more inspiratory muscle (the muscles you use to inhale) and aerobic fatigue. Hammering on the flats into headwinds and with tailwinds results in more neuromuscular fatigue in your "cycling" muscles.