There's a reason Leadville is called the "Race Across the Sky". The race starts at 10,000 ft. of elevation and climbs to over 12,000 ft. Oxygen will be in short supply and effectively lower your Functional Threshold Power (FTP). As a general rule of thumb you can expect to loose about 1% or more of your available aerobic power per 1,000 ft. above sea level, with greater losses the further up you go. So, if your FTP is 300 at sea level, plan for about 255 to 270 in Leadville. Not to say you can not go over FTP, but if and when you do you are "buying on credit" and it's going to be much harder to pay off that "debt". Be conservative and aim to stay below that ceiling as much as possible.
If you're not familiar with Intensity Factor, it's the ratio of an athlete's Normalized Power/Pace to their Functional Threshold Power (FTP)/Pace. There is a relationship between time and intensity. The longer you're out there, the lower the relative intensity will need to be. This means faster athletes will have a higher IF, while slower athletes will have a lower. For example, the winners finishing in around 6 hours will have an IF of .7-.73 (or 70-73% of threshold), while someone trying to beat 12 hours might be closer to .5 or 55%.
Variability Index (VI), is Normalized Power (or the estimate of how hard it felt) compared to Average Power (or what your power meter recorded). Because of the nature of mountain biking with stops, coasting, and potential hiking, your VI will be higher than if you were able to pedal and keep consistent power the whole time. A VI of 1.15-1.25 or higher would not be out of the question.
The model will assume that you are descending as fast as physically possible, but based on the terrain and traffic you might want to set a cap on this. For most MTB races, 25-30 mph is a good place to start but because Leadville has multiple road sections and fast, steep straight-aways, 35-40 mph might be more accurate depending on your descending confidence.
If you haven't already, go ahead and login or signup for a free account and setup your Leadville race plan. You can find the course listed as "2022 Leadville 100 MTB" or if you're logged in here's a link to the 2022 Leadville course.
Now that you have run the model and have a pacing plan, you can use it to help you prepare for race day. First you should check if you can finish in under 12 hours and then determine if you make the cutoff times. The first cut off comes at around 40 miles at the Twin Lakes pit area. And while it seems like 40 miles in around 4 hours should be no problem, this can be threatened by your corral start and bottle necks. With the changes in the course and the new corral starts this cutoff has been extended to 4:15. Highlight that section of your model and make sure you are not at risk of missing the time. If it looks like it's going to be close you might need to burn a match or two to meet the cutoff. If you don't, your race is over anyway.
Next, use the model to determine when you will reach each aid station and use that information to make decisions about how much food and hydration you will need to carry to safely make it to the next one. If you are cutting it close, you can also use this information to shed some unwanted weight to shave a few minutes off a climb.
In coming up with your strategy to cover the course in the fastest time possible, use the Time Analysis tool to see where there is the most to be gained by increasing your power, being more aerodynamic or weighing less.
I often hear about the importance of getting with a group and sharing the workload at Leadville because much of the course is on road and very fast. Theoretically you can decrease your drag by 20-30% by being in a pack. So, you can use the model to see what kind of impact that would have on your time and where the biggest gains would be had. In the example below by decreasing the drag by 20% it would net a 12 minute gain over the entire course with the biggest gains coming in the flat sections between Pipeline and Columbine. However, if you are having to ride outside yourself and above your plan, then this might ultimately come back to bite you later in the day. Looking at just the aforementioned section between Pipeline and Columbine, that would only save us 2 minutes and 40 seconds.
Everyone wants a lighter bike with all the lightest parts. But what kind of impact would being 5 pounds lighter have on your Leadville time? According to the model, dropping 5 pounds could save around nine and a half minutes over the 104+ mile course. But when you look at the dollars per gram, that is probably not a good investment. When you talk about buying speed through lighter parts most athletes can probably only hope to save a pound or two.
What if you were to focus your training time on becoming more fit and increasing your Functional Threshold Power or the amount of work you can do aerobically? As the saying goes, "a rising tide lifts all ships". So, if you were able to increase your FTP by 5% you would also increase your safe target power by 5%. In the scenario below, that 5% would translate to roughly 6 additional watts and 20 minutes faster. So there are definitely some gains to be had.
When setting up your mountain bike profile, you will obviously select "Mountain Bike Tires" as the Tire Type, but you may want to consider adjusting the Rolling Resistance (Crr). We use .0062 for mountain bike tires, but this is on the lower end and represents higher-end tires. Average tires would be around .0085 and something like puncture resistant tire would be as high as .0110. Note that the rolling resistance entered here is for the tire on average road conditions. We will adjust this number based on the road type selected in your race plan, which in this case that would be Off Road (dirt).
Obviously it is not this cut and dry. Leadville is a long day with lots of opportunities for things to go wrong such as mechanical or nutrition issues. But by using a tool such as BBS you can come up with a realistic game plan that helps you prepare for those scenarios. All models are wrong, but some are useful. While I don't use this as gospel with my athletes, we do look at it often to set realistic goals, plan nutrition, and identify any threats to our success.
Note: Because it is such a long day and there are lots of variables such as pit time, bathroom breaks, and maybe some hike-a-bike, the model will not be 100% accurate, but it can certainly get you in the ball park within +/- 15 minutes.
Take a look at Dave's Leadville race plan where you can use the Time Analysis tool to see how you would do by varying drag (CdA), power and/or weight.
Get signed up or login today to create your own Leadville model and see which buckle is in reach!
Dave Schell is the Founder and Head Coach of Kaizen Endurance coaching based out of Boulder, Colorado, where he works with off-road cyclists of all abilities. Dave is the former director of coach education at TrainingPeaks where he traveled the world teaching coaches how to better use training software with their athletes.
Normalized Power®, Training Stress Score® and Intensity Factor® are registered trademarks of TrainingPeaks, LLC.