I've been reading a bit about the benefits of short bouts of high-intensity work on aerobic performance. When I don't have much time for a workout, I try to go hard. Yesterday was one of those days.
I had less than 90 minutes to ride, once the babysitter arrived and my heart rate monitor was in place and the tires were pumped up and Buttercup and I were both ready to roll.
I tried to go as hard as I could maintain, and then do some higher-intensity miles one at a time. The heart rate was up to nearly 160 for the higher-intensity bouts, which usually got me above 20 mph. Then when I wasn't concentrating, the heart rate would drift down to the upper 130s. The funny thing was that I was still holding 18-19 mph sometimes even with a lower heart rate, which told me I had a pretty good tailwind going.
I also re-learned that it's much easier to maintain a given speed than accelerating and decelerating. And also that it's really easy and takes only moments for your average speed to drop quickly, but it's really difficult and takes a long time to bring it back up again. And cranking really hard on those pedals makes these big old thighs burn!
I ended up covering 18.3 miles (including the slow part through town) in 60:00. My average speed for 22.5 miles ended up being 18.2 mph, though. Some day that will be my sustainable speed on the bike. Right now it's my PR pace for a closed-loop ride over 20 miles. It's inching upwards, one-tenth mph at a time.
Yeah, it's all about the numbers for me! The biggest numbers that I'm keeping in mind every single day: 140.6 miles in 16:59 or less. Every workout serves that goal right now.