Welcome to Running with Rock

Thanks for clicking through and checking out my website.

I’m an avid runner and a data nerd. I write about running on this website, and my writing tends to fall into one of four buckets:

• Data analysis related to marathons and running
• Training methods and other running tips
• Rundown on Garmin running watches and other gear
• Reflections and experiences from my own running story

I’ve written a five part series comparing the Abbott World Marathon Majors.

1. Which race has the most balanced gender distribution? The least?
2. Which race has the oldest runners? The youngest?
3. Which race has the best, most consistent weather?
4. Which race has the toughest – or easiest – course?
5. Which race has the fastest finish times – among the elites and among the regular folks?

You’ll find answers to all of those questions in the series. Plus lots of in depth analysis and visuals.

Introducing my latest project: a dashboard tracking a projected cutoff time for the 2026 Boston Marathon.

I did a lot of work analyzing and predicting the cutoff time for 2025. This validated a basic assumption – if you track the number of runners who meet their qualifying times you can estimate the number who will eventually apply to run Boston.

That’s the key variable that drives what a likely cutoff time will be. This dashboard combines results from hundreds of races around the world to project the Boston Marathon cutoff time.

Participation at marathons is clearly on the rise. Races like New York City and Chicago are setting records for the numbers of participants.

But how broad is that trend? It turns out it’s across the board.

When you look at the ten largest races in the United States, they have more combined finishers than ever before. But all the way down to small races with a few hundred finishers, there’s growth year over year.

Check out this analysis of the number of finishers at races across the country this year to understand the trends.

Garmin dropped the details on its latest watches – the Instinct 3 – this week.

What’s new and what’s missing? Here’s a quick look at the three options – the Instinct 3 Solar, AMOLED, and E – and a preliminary comparison to other Garmins.

What are your thoughts on the AMOLED screen coming to the Instinct line?

Read the full article here.

Think you need to replace your running shoes after 300 miles?

I just retired these New Balance 1080’s after six months. In that time, they’ve probably seen well over 1,000 miles.

Are they a little worse for wear? Sure. The tread is worn down and the uppers are a little beat up. But they’re still comfortable and they get the job done.

I run ~3,500 miles a year, and I typically go through two main pairs of daily trainers. Some of those miles are on the trails (with trail shoes that I replace every 6-9 months), and a few are in racing shoes. But each of these main pairs will easily see 800 to 1,000 miles before they get retired.

Contrary to what the internet would have you believe, these old shoes haven’t caused any injuries. My legs, knees, and feet are fine.

But if I replaced my shoes every 300 miles … my wallet would sure be broke.

Read the full article here.

The Valencia Marathon had over 5,000 sub-3:00 finishers this year. That certainly sounds like a lot.

Was it a record setting field of finishers? I compared the results to other large, fast races – Berlin, Boston, Chicago, London, and Tokyo – to find out.

And how does it compare when you look at faster times – like sub-2:45 and sub-2:30?

Read the full analysis here.