One thing you will also notice about expert pacer’s runs is it’s not just the races and workouts that have incredibly precise splits, but even their easy runs have very little deviation from each other (once they are warmed up). It’s not uncommon for me to review my automatic splits after a run, having not paid any attention to my watch during the activity, and find that mile after mile is the exact same to the second. You can tell an athlete has a lot more potential simply based on how wildly variant their splits are during a race. As pacing is perfected, the splits are dialed in closer toward the overall average and in turn, the performance is improved.
Continuing on with the time-only theme, which I will explain more about the limitation of GPS below, the track is a great place to perfect your pacing. Staying within a foot of the inside rail, in lane one, on most tracks worldwide will be exactly 400m per lap. This is a more accurate measure of distance than your GPS, so the distance reading on your watch should be ignored. Whatever interval length you are doing you should know your intermediate splits checking as soon as 100m or 200m to ensure you are on pace. For example, 1600m (four laps, note that a mile is 1609m) in eight minutes should have a one minute per 200m (half lap) split.
I recently jumped into a track workout wearing the brand-new Escalante with some, very fast, spiked-up, high school kids who were given a targeted set of 800m intervals in 2:20 (splits of 35 seconds at the 200m and 70 seconds at 400m). They went out in 30 seconds for the first 200m (four-minute mile pace)! While five seconds doesn’t sound like much, it was 40 seconds a mile faster than the very purposeful training pace coach had given them. They somewhat jogged in the final 200m to hit the prescribed time of 2:20, arguing the goal was accomplished. But the damage was done; they had gone completely lactic in the first 30 seconds of what should have otherwise been a more aerobic section of their workout. Training physiology aside, you can still hit your time and have terrible pacing, as mentioned in the deviation variance above.
While it looked like I closed a huge 35m gap over the last 600m, in reality I ran comfortable, even splits the whole way.
GPS-MP: Understand Your Watch and Certified Courses
If I could change anything about most athletes' workouts and races it would be the reliance on the GPS watch. They are a good tool, especially for maintaining a training log and analyzing workouts, but it’s important to understand their limitations, too. Regardless of the brand (most use the same chipset), there are inaccuracies in the distance measurements used to calculate your pace which can be amplified by the route type and other factors.
When on a certified racecourses or tracks, assuming the distance markers have been placed accurately, you should generally only use your watch for duration and manually split against the official markings. Even without a flag or sign, you should be able to see paint markings for well-maintained courses. What we learned in Arizona at The Marathon Project, a course meticulously measured by one of the best certifiers World Athletics has to offer, is that our watches (all brands) auto-split about 10-30m too early (eluding to a faster pace). The very interesting takeaway is that we all trained based on our watches and while we thought an American record was possible that day, in reality, those few seconds multiplied over 26 miles add up to quite a lot.
The adjustment made in both Sara and my own training programs is a GPS-MP (marathon pace for training) and MP (certified/track marathon pace). GPS-MP, the one you use for your training runs, will be about five seconds per mile faster than MP. Another way to calculate your goal marathon pace if you want to rely on your GPS during the race is to use 26.5 or even a little more than the official 26.219 marathon distance. This will average your pace against the distance you are likely to see on your watch at the end of the marathon and be less of surprise in the discrepancy to your official result.
In mountains, ultra-distances, and trail conditions, GPS can be even less reliable, especially if you have enabled battery saving mode which will decrease the polling rate (the interval your watch updates your location) up to a minute. This can result in missed turns you’ve made since the last point and can cut your distance significantly—not to mention coverage issues.
You should also factor in stoppage time at aid stations to your average pace goal as the official clock never stops. A few minutes add up quick over the longer races with more aid stations. I have been putting my Timp 2’s to the test on extremely rugged terrain and harsh weather in the mountains of Norway the past few weeks and have to rely entirely on effort or perceived exertion to properly pace the various grades which can go from 12:00/mi on the steep climbs to under 5:00/mi on the gnarly descents (these shoes give me a ton of confidence!). It all averages out to the same Grade Adjusted Pace (GAP) which takes elevation gain/loss into account.
Rather than relying on mile-by-mile splits, it’s better to break the course into sections, focusing on trying to average a certain pace between landmarks on a larger scale.