Monstercross '24 - the analytical follow-up post

This year was the first time I made no changes to the bike. I had just installed the SRAM Force AXS XPLR groupset before last year's race, had just bought and configured the Sun Ringle Duroc G30 wheels & WTB Resolute tires & 10-44 XPLR cassette, and even last year's bar tape was still present.

Literally the only changes were a new set of pads & front brake rotor, although a review of last year's blog post suggests I was running a lower tire pressure then at 25 psi, compared to my 27f/28r split this year. That's a sizable difference considering my race-morning weights were within 0.5 lbs of each other.

Last year the race was considerably warmer, and I was wearing standard cool weather kit. This year I was in much more aero materials, from the Velotoze neoprene gloves (with hand-warmers stuffed inside on top of my knuckles) to the Castelli Perfetto ROS2 jacket that I'd first tried on the NYD not-a-race.

I've talked about how my training tends to fall off in the Autumn, and I track fitness, form (freshness), and fatigue through pretty standard algorithms in intervals.icu (it shows almost identical data to Sauce, Elevate, and others), along with various elements from Veloviewer and other sources:

In 2020 and 2022 I got off and walked after seizing up, and in 2021 we ran a modified course, so we'll start by discarding those years. This is convenient because I also didn't have power back then, and I evidently didn't explicitly track tire pressure or my race-day setups.

Looking at this year's data, though, I came into the race with a MUCH higher fitness score than in previous years, and in spite of higher average and normalized power numbers, ended with a better form number than ever before. Fatigue was high, but it took a lot of work to get to that fitness number.

In fact it took since December 1, when I got roasted alive in a Zwift Fondo and decided to put in ~12h/week, as mentioned in my previous post.

That day, as indicated by that lone purple dot, marked the start of my march from a consistent ~73 fitness score up to 90 by January 23, with a taper that was only quasi-intentional putting me on a positive form number of 14 the day before the race.

Lots and lots of Z2, folks. Seriously: it's transformative. The easiest way for Garmin users to get the bigget bang for their buck is to turn on both Training Effect data fields: aerobic (~Z2 & 3) and anaerobic (~Z4+). I started training to these numbers, targeting an aerobic score of 3.5 - 4.9 for every ride, and only doing anaerobic work a couple of times per week. Watching these numbers has turned my Zwift time from junk miles to productive training. I cannot advocate for it enough.

But as I also mentioned in my previous post, the other big change was watching W' bal. W' is the is your anaerobic battery--your matches, if you will. It's not the easiest thing to calculate--your estimates are guaranteed to be wrong, and the numbers can and will change over time. But essentially it's scored by your max power over various intervals, say 2, 5, and 10 minutes, and using the drop-off (ye olde power-curve!) to determine how many Kj you have in your battery. Go for a big sprint and watch it drop to 0 almost instantly, or do a long surging climb and watch it drop slowly, but any efforts over critical power (which is roughly equivalent to FTP) will drain it. Conversely, riding *below* critical power refills it over time.

I started using W' bal in Zwift rides to get a feel for it, and holy moly it was amazing. Suddenly those times I felt like I couldn't carry on, I had data to show that was a lie. Because we all know the mind quits before the body. And by looking at the data instead of listening to my body, I held onto some groups that would absolutely have dropped me before.

But because W' bal also recharges, it's also instrumental in gauging recovery in a race. My 4th overall segment attack on Monsterkarst the week before the race was paced entirely on W':

This chart shows W' in red overlaid on power. Power, alone, can be hard to really interpret. You can see my first 20 minutes or so are fairly consistent, and W' remains nearly full, but when it gets spiky it's hard to see where things are dropping off. W' shows that data clearly, and the Garmin data-field shows it as a percentage, so you can track your effort clearly.

That same data for the race shows what was happening in that first lap, and how the balance changed when I got on the skis out in the wind:

That opening effort to Beach Rd, with all its bridges and power spikes, had me on the ropes. And while I got tired through the rest of the race, I was never in deep trouble again.

So I finally cracked the 3 hour mark, and I did it with over half the race being out in the wind. I absolutely believe I would have been 5 minutes faster if I'd been able to reach the front group before Beach Rd, but where to go from here?

A review of my shifting data from the SRAM app shows a larger chainring could optimize my chainline, with the lion's share of my time spent in the outer 3rd of the block.

I've been running a 40T chainring for so long I'd be nervous to depend on something larger, but the math says a 46T would move the peak back 2 gears, while only losing a single gear off the bottom--a gear I only used for 9 seconds all day. If I can find an aero 46T 110-BCD 5-bolt NW oval chainring before I give up on gravel for the season, I may have to try it out...assuming my power and fitness are in the same ballpark next year.

And that's the rub. Last year I was flat thru the Fall and got COVID in January. This year I was making huge gains from December to late January before getting wobbly and forcing myself into a taper. There's no telling what the future holds, but for now I'm extremely satisified with my results.