Will the New Rules for Downhill Races Impact the Boston Cutoff?

The BAA made two changes to registration for the 2027 Boston Marathon. The more subtle change involved the start of the qualifying period and eliminating the ability to use a small subset of races to qualify for two different Boston Marathons. The big news was the new rules for downhill marathons.

For years now, (some) runners have complained that downhill races offer an unfair advantage. They’re a cheat code to get faster, shave minutes off your time, and qualify – or make it past the cutoff. With large cutoffs for the 2024 and 2025 Boston Marathons, this grumbling grew louder.

Over the summer, the BAA made a shock announcement – they’d be implementing a downhill results index and adjusting times from downhill races that meet certain criteria.

What Is the Downhill Results Index?

The new rules for downhill races, known as the downhill results index, are pretty simple. Races are classified in one of three groups:

• Races with less than 1,500 feet of net drop
• Races with 1,500 to 2,999 feet of net drop
• Races with 3,000 to 5,999 feet of net drop
• Races with 6,000 or more feet of net drop

Net drop here means the change in elevation between the start of the race and the finish. A race can have much more total elevation loss than net drop if it also includes rolling hills or other inclines. But this additional elevation loss is balanced out by the additional gain throughout the race. It’s the net that drop that matters and helps you run faster.

The first group of races, with less than 1,500 feet of net drop, is not impacted all at all. These races do not receive a modifier or penalty. This includes some races with a moderate loss of elevation.

The second two groups have penalties applied to qualifying times submitted from them – five minutes for the first group and ten minutes for the second group. So a runner who needs a 2:55 to meet his BQ will instead need a 2:50 or 2:45.

The final group is simply not allowed. You cannot submit a qualifying time from a race with 6,000 or more feet of net drop. This would be hard to do, though, because there’s no certified race that I know of with this much elevation loss. But perhaps this was forward thinking by BAA to prevent race organizers from just increasing the elevation loss to compensate for the ten minute penalty.

Which Races Are Impacted?

The collection of races that are actually impacted by these rules is fairly small. Of 250 races that I track for use in the Boston Marathon Cutoff Time Tracker, less than 20 fall into one of these two groups.

The larger group is the one hit with a moderate decline and a 5:00 penalty. There are a half dozen marathons with similar courses that go through the Snoqualmie Tunnel, along with St. George, Las Vegas, Utah Valley, Tucson, and REVEL White Mountains Marathons.

The group of steeper races with the 10:00 penalty is smaller. This includes a few smaller races (Deseret News Classic, Mt. Nebo, and Huntsville) along with three big REVELs (Big Bear, Big Cottonwood, and Mt. Charleston). There are two or three additional races that fit this criteria – but they’re so small that I don’t include them in my sample of races.

There are another ten races that have mild downhill components and are not impacted by these rules. This includes races like Colorado, Mesa, and Mountains 2 Beach.

In April, I did an analysis of how many runners from downhill marathons made it into the 2025 Boston Marathon. This was before the new rules were announced, and so this isn’t a precise measure of the impact of the rules, but it’s a good first look at how big of a potential problem this is.

That year, about 5,000 runners notched a qualifying time on a downhill course and about 2,000 of them actually ran the 2025 Boston Marathon. At the time, I noted that a significant number of those runners had a sufficiently large buffer that indicated that they could also have qualified on a flat course. Now that the rules have established a clear penalty, it’s also evident that a significant number of these runners could overcome a 5:00 or 10:00 penalty and still be eligible to use their qualifying time.

What Impact Would This Have Had in 2026?

Since the rules were announced, I’ve had a few people ask what impact this would or could have had if it was applied to applicants for the 2026 Boston Marathon. I took a preliminary look at this a couple months ago, but there were still some races yet to be run. Now that the qualifying period is over, we can take a look back and see.

Compared to the 2025 Boston Marathon, this qualifying period had fewer runners and qualifiers from downhill races. REVEL Rockies was retired in 2024 and REVEL Big Bear had its marathon canceled due to weather conditions.

In total, there were about 19,000 finishers at marathons that would have been eligible for downhill results indexing. About 3,300 of them notched qualifying times – and 1,300 of them would not have qualified if they were subject to the time adjustment. That means that 2,000 – about 60% – still would have qualified.

The visual above shows the percentage of runners at a given race that would be adjusted out of a qualifying time. St. George is the biggest race here, but a relatively small portion of it’s runners qualify – and only 2% of them would be eliminated by the adjustment.

At the various tunnel races, anywhere from 15-25% of the finishers would still meet their qualifying times. Another 7-9% would no longer qualify with the time adjustment. The percentage of possible qualifiers that would be eliminated by the adjustment varies between around 30-40%.

And here is the same visual for the steeper races with a 10:00 adjustment. Compared to the other races, runners at these races are more likely to be impacted. In most cases, more than 50% of the possible qualifiers would be eliminated. Although at REVEL Mt. Charleston, this still leaves just under 20% of the field as qualifiers – in spite of the adjustment.

Of the 1,300 runners at these races who would have been eliminated by the adjustment, about 400 had a result from another race in the qualifying period and a little more than 100 of them had qualified at that other race. So the rules would result in a net decrease of about 1,200 qualifiers.

We know that qualifiers from these races apply to Boston at a high rate – 60 to 70%. For the sake of argument, let’s go with a high end estimate of a 75% conversion rate. That would result in 900 fewer applicants. That’s equivalent to about 30 seconds on the cutoff, give or take.

What Will These Rules Mean For Next Year?

This doesn’t necessarily mean that the new rules will eliminate 30 seconds from this year’s cutoff time, though. A few things have changed.

First, at least two races have modified their courses to avoid the penalty – Tucson and Utah Valley. They were just above the threshold and now they’re just below the threshold. Runners will likely see a similar boost from the elevation loss and qualify at similar rates, but no one will be eliminated. So that’s about 100 fewer eliminated qualifiers. Most of the other races are too steep to make this change, but Cascade Express and the Super Marathon are close enough that it’s possible they follow suit.

Second, there will be some changes to the actual list of races. REVEL White Mountains has been retired, which means fewer qualifiers in general. But they’ve also added a new race this year – Reno Tahoe. It’s hard to say for sure how many will qualify at Reno Tahoe, but let’s assume it washes out with the absence of White Mountains. But REVEL Big Bear will also return. This was a huge qualifying race missing from the last qualifying period – and despite the adjusted times it’ll likely inject an additional 300 to 400 qualifiers into this qualifying period.

Finally, there’s the unknown factor of what runners will actually do. We applied these adjustments to last year’s runners – who didn’t know they were being penalized. This year, some subset of runners will either a) target a faster time or b) run a qualifying time on a flat course. It’s hard to quantify how big this effect will be, but the number of adjusted runners will likely be smaller than it was last year.

If we start with the baseline from last year (1,200 adjusted qualifiers), remove 100 due to course changes, and offset 400 from net additional qualifiers at Big Bear we’re left with a net decline of 700 qualifiers compared to last year. Assuming the same application rate, that’s about 500 fewer applicants. That brings the net impact on the cutoff time down to about 15 seconds, give or take.