Looking to Qualify for the Boston Marathon? Here’s What Strava Data Says About That Elusive BQ.

In our monthly column in partnership with Strava, we take a deep dive into compelling data points that reveal the more human side of sport. 

In 2023, a record-breaking 33,058 athletes applied for the 128th Boston Marathon. Of those, just 22,019 were accepted (pending final verification). Qualifying times are established for different age and gender categories. Still, with so many applicants, the unofficial cutoff times for acceptance were five minutes and 29 seconds faster than the official qualifying time many athletes push for.

Looking at data from several 2022 marathons, interesting trends emerge. We analyzed Strava data from the Berlin, Chicago, Marine Corps, New York City, CIM, and Valencia marathons. Here’s what the data tells us about qualifying for the Boston Marathon.

A Quick Note on Courses

Before we get too deep into the data, it’s worth discussing the fact that the above courses have different course dynamics and demographics, which influence median finishing times. Berlin, CIM, and Valencia are all fast courses that attract folks gunning for a BQ. (Hola Valencia! Peep that four feet of total gain, with a net descent of 106 feet.) CIM has a particularly high percentage of BQs since it combines a fast course with a smaller field—many run CIM specifically to qualify for Boston.

Last year was a record-breaking heat year at the NYC Marathon, which resulted in an anomalously low negative-split rate. More than 2,000 runners didn’t cross the finish line in 2022, with temperatures soaring to 75 degrees with  75 percent humidity, which radically affected finishing times. We’ll still look at data from NYC, but 2022 was exceptional. Only 30 percent of runners at NYC who were aiming for a sub-three finish met that goal, and only half of runners looking to go sub-four did so.

Training for A BQ Versus Training For a Marathon

Across all the marathons we analyzed, athletes had similar training. Most started at a base of around 20 miles a week and a 10-mile long run. On average, they worked up to a 30-mile week and a 20-mile long run. While there’s a slight variation in average miles per week (mpw), the training time in the peak week is similar (and each race has a different mix of target paces for participants).

CIM had the highest average mileage baseline and peak week, suggesting that it attracts more experienced runners with a specific goal in mind. CIM runners started with a 30 mpw base and progressed to a 50-mile peak week and 21-mile long run. BQ runners at CIM started with a 43-mile peak week (the highest of any marathon analyzed). When we just look at athletes who hit the BQ standard to equalize the field, CIM runners have a higher baseline and peak week.

While many newer distance runners tend to focus on flashy long runs, the distance of the longest run was not strongly correlated with a BQ. Comparing BQ runners and all other athletes, the distance of the longest run was 20 to 22 miles across each marathon. But, the base mileage was higher for BQ runners, bearing in mind that base volume matters more than the distance of any long run. BQ runners at CIM averaged 65 miles during their peak week, while the rest of the field averaged 50 mpw. Similarly, Chicago BQers averaged 57 miles during peak week, compared to the rest of the field’s 41 mpw peak week.

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Interestingly, there was not a strong correlation between success on hillier courses and runners averaging more elevation gain in their training. Across all races, BQ runners did have more elevation in their training. For example, CIM and Berlin BQers had 15 percent more elevation gain in their training than runners who didn’t BQ (even when you control for average mileage). CIM runners hit the most vertical gain, averaging 100 feet of elevation gain per mile over the training cycle.

Speed and Experience

There’s no teacher like experience, and marathons are no different. Runners who finished one of the above races between 2:30 and 2:59 on average have completed six previous marathons. Runners who finished between 4:00 and 4:30 had completed, on average, four previous marathons. Experience helps with pacing, fueling, and other elements of the marathon that are sometimes only learned through trial and error.

Chilling Out

Keep easy days easy. There’s a strong positive correlation between keeping training runs intentionally slower than race pace and runners hitting their goal pace (defined as the pace runners averaged over the first eight miles of the marathon). Running slower than marathon effort helps build dense capillary beds, strengthen the heart, increase stroke volume (the amount of blood your heart can pump per beat), and increase the endurance capabilities of your muscle fibers by increasing the number of mitochondria in muscle cells. Running too fast causes the breakdown of bone and muscle tissue at a rate that can’t be outpaced in recovery; plus it makes the body less efficient at processing oxygen.

Runners that kept easy runs about 30 percent slower than goal pace had a 27 percent success rate, finishing at or close to their goal time. For runners who did easy runs only 10 percent slower than their goal pace (the approach of about a third of the runners analyzed), only 19 percent met their goal time, equating to a 31 percent reduction in success rate. Of runners who did “easy” days around marathon pace, only 14 percent hit their goal time.

Faster runners, who are more experienced, keep easy runs easier. Runners who finish in 2:30, on average, run their easy days 29 percent slower than goal pace. Compare this with runners who finish an hour later in 3:30, whereas the average runner ran their easy days just 11 percent slower than race pace, and only 20 percent hit their goal finish time.

Runners aiming for a 3:00 marathon (6:52 mile-pace) should shoot for easy days between 7:48 and 8:36. Runners looking to hit a 3:30 time (8:01 mile-pace) should strive for easy days between 9:02 and 9:56, and 4-hour marathoners (9:09 mile-pace) should shoot to keep easy days between 10:11- and 11:11-minute miles. As demonstrated by the data, to go fast, you have to learn to run slow.

Course Choice and Negative Split

Of all the courses, CIM and Valencia had the highest percentage qualifying for Boston, with 32 percent of the field BQing. Only six percent of NYC runners hit the Boston standard (heat!), and the Marine Corps Marathon, popular amongst beginner runners, had a similar qualifying rate. At Chicago and Berline, 18 percent of the runners qualified.

NYC and Marine Corps had the slowest median finish time, just over 4:30, averaged across all runners (NYC usually runs faster in cooler years). NYC is also the largest race, with over 47,000 competitors (compared to CIM’s 10,000). Valencia had the quickest average finish time (3:28), with a relatively small field of 30,000 runners.

Even more than gain and loss, the strongest predictor of BQ success was a negative split, running the second half of the race faster than the first. Take, for instance, Kelvin Kiptum’s recent world record win in Chicago, in which Kiptum ran a 59:47 negative split to run just 35 seconds over the two-hour barrier.

Just three percent of NYC runners (the heat! The humidity!) negative split in the rising temps, again pointing to an outlier year in NYC. Eleven percent of runners negative split both Chicago and Marine Corps, but experience won out in the Chicago crowd, with its 18 percent BQ rate, eclipsing Marine Corps’ six percent (a race that traditionally has more beginner runners).

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Berlin and CIM both boosted a 16 percent negative split rate, though a higher percentage (32 percent) of CIM runners hit the BQ compared to Berlin’s 18 percent. Valencia had the highest percentage of negative splits. Still, a significant portion of that can be attributed to the extremely flat course, with just enough downhill to boost speed but not enough to bash the quads too badly.

So, if you’re searching for an elusive BQ, here’s what the data show: slow your runs down, choose your course wisely, shoot for a negative split, and remember that practice makes perfect. It may take a couple of marathons to get it absolutely right, but that experience will be invaluable.