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  • Writer's pictureTim Bradley, Sr. Director of Training/Interim Executive Dir.

Evaluating Your Long Runs

Updated: Sep 21, 2022

As we hit the last few weeks in August, many runners who are preparing for the Chicago Marathon are now up to at least 16 miles for their long run. At this time in training it is natural to start taking a hard look at each of your runs and trying to estimate your current fitness. This is to gain confidence and evaluate if you are on track to hit your goal time or will be able to complete 26.2 miles come race day. Below are some of the most critical factors to look at when evaluating your long run and what you can extract out from those key Garmin numbers.


Weather…specifically heat and humidity, continues to be a major factor for any summer

long run. This factor really determines how challenging the day will be and how accurate of a fitness assessment the long run might be. When evaluating your fitness, post run, make sure to weigh this factor heavily. We all know what it feels like when it is hot and humid and will impact how we feel and what we can possibly average for a long run.

Overall Pace:

Average pace for the duration of the long run is essentially the most important

number to look at, besides overall distance of course. Your average pace for the long run is the most comparable

number and will inevitably lead to common questions like, “If I can run a 9:00 min. pace for 20 miles in training, could I run 8:30 or faster in an actual race?” Or something along these lines, depending on your pace and goal time. This is a natural question and one you should certainly be considering in the following weeks. However, make sure to weigh the weather properly, along with the other important factors below.

Cardiac Drift:

Since many wearable devices can measure heart rate nowadays, looking at your graph and seeing how much your heart rate drifted up is a great way to evaluate your fitness. The more level your heart rate is, over the course of the run, the better. If you are seeing your heart rate go from the low

60% range all the way up to a race-like effort in the upper 80s or 90% range, then you need to consider that more of a race effort than a training effort. This basically means what you just ran in training is probably where you are going to be at in a race.

Direction of Splits:

The direction of your mile splits can really tell more of the story of your long run and whether you were finishing strong or fading fast. Typically you want to see your splits stay as steady as possible, but you can expect a wider range the longer you run. The overall bottom line though, is whether you were speeding up or slowing down as you completed the final miles of your run?

Final Thoughts:

Taking all of these factors into account can really give you the entire picture of the long run and how it relates to your cu

rrent fitness. Using multiple factors and understanding the different angles that go into a long run, gives you a better idea of how any given race might be impacted by weather, pacing and your own assessment of your fitness.

All marathon season long, please feel welcome to direct questions to me, Tim Bradley, Sr. Director of Training and CARA Head Coach at

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1 Comment

Steele Nickle
Steele Nickle
5 days ago

 When evaluating your fitness, post run, make sure to weigh this factor heavily. geometry dash lite

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