Well, lying probably isn’t the right word, but sometimes your average pace doesn’t tell you the entire story. If your splits are like clockwork and you knock out a run keeping the same pace the entire time, then your average pace is probably your best friend and an accurate indicator of the workout. But — if you are like me — and you tend to bounce around with your pace, then your average pace time can be somewhat deceiving.
Note: when I say “average pace,” I don’t mean the current average pace while running. I mean looking at an average pace AFTER the run is completed. Also, the average pace after running CAN be a completely accurate indicator of the intensity of a workout. Not less than a few hours after writing this post, I ran 14 miles with an average pace that told the whole story.
Here is a tale of 2 runs that look entirely the same, but couldn’t have been more different.
- 18 miles, 9:07 avg. pace
- 20 miles, 9:04 avg. pace
Those two runs look very similar don’t they? On the surface it looks like two runs by someone who has a pretty consistent pace across two long distance runs. But let’s take a closer look and see how different they really are.
Starting off strong?
18 mile (first 10 miles)
8:21, 8:27, 8:29, 8:06, 8:28, 8:33, 8:13, 8:18, 9:03, 8:52
That’s a lot of 8’s for a run that averaged 9:07, in fact, there is only 1 mile above the 9 minute mark
20 mile (first 10 miles)
9:09, 9:14, 8:54, 9:03, 9:04, 8:54, 8:38, 9:10, 9:02, 8:57
That is a much different story. The splits are closer together and only 1 dips significantly from the average.
In looking at the first half of both of these runs, it’s clear that the 18 miler has a much stronger run to start. There are some low 8 minute miles, but it’s all over the place ranging from 8:06-9:03 with a 57-second difference, which is a big jump in pace. The 20 miler has a more consistent feel to it, even if the miles are slower with a difference between miles at 36 seconds.
Let’s see how the rest of the run plays out.
18 mile (last 8 miles)
8:22, 9:10, 9:26, 10:05, 9:37, 9:56, 10:58, 11:35
As you can see, the wheels completely come off on the 18 miler with the final 5 miles being over a 10 minute average.
20 mile (last 10 miles)
8:53, 8:48, 8:42, 8:51, 9:00, 9:37, 9:29, 9:13, 9:34, 9:17
Even though there is a slight increase in pace on the last 5 miles of the 20, it stays within range of the 9 minute average.
Looking at the average pace of both runs, they look very similar, but the 20 mile run was a much stronger, more consistent effort (over a longer distance). In my last training cycle, I struggled with the long run with most of them looking very similar to the 18 mile run. I would start off with a pace close to what I needed, then fade, fatigue and succumb to walking the last few miles. After that 18 mile run, I saw a very similar pattern and made a conscious effort to start slower on the 20. Even though I slowed on the last 5, I didn’t blow up and kept reasonably close to the average pace.
I would have loved to have been able to drop the hammer on the last 5 of that 20 and get those splits to sub 9’s and closer to low 8’s — that was what I was hoping would happen. But when I knew that the legs didn’t have it in them, the goal shifted to continue running at the current pace. I didn’t want to see splits in the 10’s like the previous week. I was going to keep moving forward. Sometimes, that’s what it comes down to, adjusting goals on the spot.
I love looking at data post run to see where things went right and where things may have gone wrong. I run with the Garmin fenix 3 and Garmin Connect (mobile/desktop) is able to feed me data on splits, elevation gain/loss, cadence, stride length, and temperature. Sometimes there are clear indications (temp. or elevation) that instantly show me why my pace increased/decreased. It’s not something I do after EVERY run, but it’s something that I find useful post long runs and/or tempo workouts.
Are you a data cruncher when it comes to your splits?