Friday, May 30, 2008

Crunching Numbers For Ultras - Ultra Calculator!

Sometimes planning an ultramarathon can be overwhelming. How many gels do I need? How much electrolyte will I have to make up? How much longer will it take to finish if I run 2 minutes per mile slower and how many more gels and bottles of electrolyte will it take? Sure, it's easy to just say "No problem, I'll just drink one bottle and take 2 gels per hour. Right?" That's all well and good in theory, but what happens when aid stations and access to water and food are not evenly spaced or there are significant gaps which can take in excess of an hour or two to cover?

Case in point, I was looking at the Sawtooth 100-miler aid station chart. Many of the stations are in excess of 7 miles apart. Given an average historical pace of about 18 - 20 minutes per mile, that means it might take you 2+ hours to reach the next station. Now, if you were planning on carrying 22 ounce water bottles and hydrating at a typical 32 ounces per hour, you'd need to carry 4 to 5 bottles with you. Duh oh! Maybe it's time to invest in a hydration pack, ya think?

Anyway, my point is, running ultras requires some serious planning and calculating. Of course, it's nearly impossible to figure in all of the variables, but having a way to help analyze and plan your race is essential. This inspired me to create an Ultra Calculator.

What's an Ultra Calculator you ask? Well, here's what it is and does. It's an Excel spreadsheet I designed that requires you to enter the distances at which each of the aid stations are located. Then you enter in your projected pace per mile, how many ounces of fluid per hour you drink, the fluid carrying capacity of your bottles/hydration pack, total calories of your fluid carrying capacity, calories per gel pack, and your race start time. Once you have entered this information, the spreadsheet will calculate the following: distance to next aid station (AS) in miles; estimated time to reach the next AS in minutes; your cumulative race time in minutes, as well as in hours and minutes; estimated arrival at each AS in military time (handy for your crew and pacer); estimated ounces of fluid consumed/needed between AS's; estimated calories consumed/needed between AS's; estimate of how many bottles/hydration packs you'll need between AS's, based upon their carrying capacity, hydration, and caloric needs; and finally, how many gels you'll need between AS's, based upon caloric need. WHEW!!

I know it sounds like a lot, but it's actually rather simple and might help you get a better grasp on how to plan your next ultra. Here's a link to the file if you care to download it and give it a try. In the file I've included 3 tabs, one which is a blank form, and the other two are the Kettle Moraine and Sawtooth 100's for 2008.

Feedback and suggestions are welcome!


keith said...


Seeing as you are a blogger on my blog roll, I'm personally taking the time to inform you that

Keith-In-Training has a new address!

Please visit:

Make sure to update any feed reader subscriptions, as well by clicking the "subscribe" links as well!

You can delete this after you have updated your feed reader and/or bookmarks. I just didn't have your email.

Thanks & Happy Trails!


Phil Robertson said...

I tagged you on my running blog. To find out how to respond, just visit my blog.

Enjoyed reading your blog.


Joel said...

Okay. I'll take a look at the calculator you created. it looks great, but maybe beyond what my mind can comprehend.
Hope to meet you out on the trail.