Race Analysis: Alex Howes at Leadboat 2021

After a challenging day in Leadville, Alex saw victory on day two, finishing in first place at SBT GRVL 2021. After his win, we asked EF Education-NIPPO coach Nate Wilson about Alex’s weekend on the bike. Using heart rate (HR) data from both races, Nate analyzed Alex’s Leadboat weekend. Read on for Nate’s analysis.

What are the similarities and differences between these two events?

The Leadville Trail 100 and SBT GRVL are both long endurance events that take place at altitude. You can see from the summary data above that the temperature and duration on both days were very similar. Diving into the details, however, there are some significant differences that have big implications.

First, the average elevation in Leadville is 3,095 meters (10,154 feet) and in Steamboat it is 2,201 meters (7,221 feet). So both events are really high up there, but since the detriment that occurs at altitude is more of an exponential response than a linear response, each 500 meters of elevation can make a big difference! Growing up at altitude, and living at 2,500 meters, does give Alex an advantage at altitude. At high elevation, hard efforts — regardless of the profile of the course — become more about a rider’s ability to sustain a hard aerobic pace and cope with minimal recovery. The fact that higher elevation coincides with long climbs up into even thinner air — Leadville’s high point is 3,787 meters, 12,424 feet — means that this race is a much different effort than SBT GRVL, which occurs on average at a much lower elevation, and sees no long climbs like Leadville. We can see this in a bit more detail by looking at the HR response in each race.

Alex’s threshold HR is 172 bpm. In the file above we can see that in the first half of Leadville, Alex was already frequently doing 10+ min sustained periods close to his threshold HR. These are all on steep climbs, mostly 7-8%. So it makes very clear the simple demand of Leadville 100. That is, the ability to sustain that high aerobic workload with limited recovery. These demands are a combination of the profile (big climbs) and the altitude (forces recovery to be limited).

In SBT GRVL, we see a totally different course profile with fewer big climbs, and lower elevation. So what we expect to see is that there is less sustained work around threshold HR. Due to the length and elevation (still high!) of the event, aerobic endurance is still a huge part of success in an event like this, but it is a few degrees removed from the aerobic demand of Leadville 100. How does this translate to racing? It allows the deciding moments of the race to be a bit more intense. We don’t see that as much in the HR response, because these can be really short moments (like the final sprint) that aren’t long enough to show a huge aerobic response, but we would really expect to see it in a power file showing shorter, high power efforts. By looking at the HR response we can see the lack of sustained high HR compared to Leadville.

In the highlighted sections of the file above we see some of the highest HR moments from Steamboat, and they are all lower HR and shorter bouts than what we saw the day before in Leadville. Some of this is likely due to the difference in the nature of the course and how the race played out. A lot of the key moments were only about 5 minutes, which isn’t a lot of time for the HR to really get up high. That is a big difference from Leadville where already early in the race the group is going hard up 10+ min climbs. We also have to keep in mind the influence of fatigue on HR. As fatigue builds, in a multi-day period, HR often gets suppressed for the same perceived effort (or power). The lower HR at Steamboat compared to Leadville is not just from the racing being lower elevation and shorter climbs, it is a combination of those factors and the fatigue from the day before.

How does the Leadboat weekend compare to a WorldTour stage race?

The HR-based TSS gives us a good sense of the overall aerobic stress from these races. The HR TSS for Leadville was 383 and for Steamboat was 316. In June Alex raced the Tour de Suisse. The two highest back-to-back HR TSS days had HR TSS of 238 and 236. So that really shows how high the load is in these big off-road events! They’re definitely not easy. For an additional data point though, Alex’s Amstel Gold Race file had a TSS of 360. The duration of AGR was a bit below 5.5 hours in 2021, so the rate of TSS accumulation (which gives a sense of the intensity) is a good bit higher, considering that we see similar TSS to Leadville but in about 1.5 hours less time. So in a very simplified way the similarity between a race like Leadville Trail 100 and the Amstel Gold Race is the overall load, which has a big impact on the recovery, and the difference is the amount of high intensity.

If we had power data from these events we would get a clearer picture of the similarities and differences from these events compared to a European WT race. With HR we can get a sense of the overall aerobic stress, but that is not the only thing that makes a race “hard”. A race could have a lower average HR, or shorter duration, but be perceived as “harder” by the rider because the most intense moments were more impactful in their perception of fatigue than the duration or overall aerobic load. This is something that I believe will vary athlete to athlete based on what they're most trained in at any given moment.

One final note: An interesting thing that Alex mentioned after Leadboat is that the Sunday prior he got caught riding on a bad wildfire smoke day, encountering some very bad air quality. Then, for the whole week leading up to Leadboat (and during the races) there was a notable difference in his HR compared to his pre-smoke exposure HR. Before the smoke exposure, his HR was getting into the 170s pretty regularly, but even at Leadville that barely happened. Given the wildfire season that the western United States — and many other locations worldwide — is seeing, this is a factor that could affect many athletes.