So me and a bunch of my buddies are competing to see who can get the fastest time on a specific stretch of singletrack - an Internet individual time trial, if you will.
The course is 5.7km of swoopy singletrack. There's no hills to speak of, and the course surface is fairly hard and fast. There are a couple of minor technical sections, but the majority of the course is one flat-or-slightly-banked turn leading into another.
My current record time is 20:18, and my last 5 or so attempts have been in the 20:18 to 20:30 range, with the average being 20:25. This represents a substantial improvement from when I started (averaging 23-ish) but I seem to have plateaued.
The fastest time anybody has completed this course is 18:40, there is an 18:58, and a smattering of mid-19s. The guy one place ahead of me is 19:55.
I'm not the slowest guy there, but I would very much like to break the 20:00 mark at least.
I'm confident that it isn't the bike; I'm on a Norco Phaze XC full squish with 120mm rear, 130mm font. I'm on Race King 2.0 Supersonic tires, and the bike handles great. I weighs a tick over 28 lbs, which isn't great, but it isn't horrible either. I'm also a former race car driver, so I understand how to corner and what the racing line is; I'd be willing to believe that there is still time to be found in how speed is carried through different corners and so forth, but I'm certainly not sucking in that regard.
Instead, I'm pretty certain that my strength or endurance is the issue. The course is very much "brake for corner entry, accelerate out of the corner until the next brake point" over and over again. By the midpoint (at least) my legs feel like lead, and it's tough to spin up for the next fast section. It takes visceral effort to force myself to accelerate after each turn, rather than just rolling through it, and it feels like each subsequent effort is just a little bit less than its predecessor.
My heart rate trace shows that I hold a pretty steady 160 +/- 5 BPM, except for one straight section where I get up to about 170 or so (followed by a strong dip to 150 as the course enters a slower section and I try and recover) Perceived exertion runs between 7 to 10.
I have tried going out hard and holding it as long as I can; I have tried starting slower and building; I have tried an extended "pace yourself" followed by a stronger finish - everything seems to produce the same time.
I thought maybe I had overtrained and needed a rest, but 5 days off the bike produced an effort that was no stronger or faster.
Clearly, the engine needs work, and as winter approaches there is an opportunity to shift to weights and/or the road trainer in an attempt to build the engine.
So the questions are:
1. What exactly should I be concentrating on?
2. What sort of workout builds the answer to question 1?