How running slower make you faster in the end
At Airia we have based our shoe development around performance tests. Namely the “double 5k all out time trial” which you can read more about here. To help test runners run as fast as possible to beat new PBs it has been important to work with them on their pacing strategies.
Let’s start with an example of a runner trying to run 5k in under 20 minutes for the first time. She knows that she has to run every km under 4 minutes (48s / 200m lap). Her PB from before is 20min 25s so she has to shave off an extra 5+ seconds per km. Feeling the pressure and being highly motivated she goes out hard with the first two laps (on a 200m track) of 42s and 43s. This pace is equivalent to a km time of 3m 30-35s and if she could hold this pace it would mean 17m 30-55s for the 5k. After these first 2 laps she has gained 10-12 seconds on her 20flat schedule. The bad thing is that because 42s laps are much closer to her maximum speed she is not at all running as efficiently as she would have done on 48s(which is 4min/k). Because of this her muscles have been working much harder than necessary and are already more fatigued than needed.
Working this hard in the beginning also means that the body temperature will rise faster and that in itself is a limiting factor for performance. With this type of “sprint” opening she will be fighting the consequences of it all the way to the finish line. Below are her km times for the 5k.
|3,40||after the fast opening she slows a little but still running around 45s|
|3,58||already here the lactic acid buildup starts to slow her down. 47,5s|
|3,59||pushing everything she’s got and keeping lap times under 48|
|4,20||Willpower can’t do it anymore. Legs are wasted. Lap times up to 55 in the end of the K.|
|4,40||stabilizing on 55-56s laps and finish totally exhausted.|
Her finishing time would be 20m37s. The feeling afterwards is terrible.
I’ll give an example of a better paced race below.
|4,05||taking the first 2 laps really easy (49-50s) to get going. Then she starts doing 48s.|
|4,00||now sharpening the pace a little and doing 47,5-48,5s. Now the race starts|
|4,00||Her rhythm feels great and legs still ok. 47,5-48,5|
|3,57||She speeds up a little doing only 47s/laps now. Mentally preparing for the final km|
|3,40||She makes a long acceleration with what’s left in her legs 46-45-44-43-42 laps.|
Finishing time for this example is 19m 42s. This is a much better paced race. She had trust in herself to hold it steady for long and not to fall for the temptation to waste those fresh legs in the beginning and when it really mattered in that last Km she gave it her all.
When comparing heart rate between the two strategies the first would probably have a peak earlier (maybe at the end of km 3) while the other is peaking at the end of km 5. Most likely she would be able to reach a higher heart rate with strategy 2 because lactic acid wouldn’t be limiting muscle work until the very last laps whereas it already starts to slow her down at the end of the second km when using strategy 1.
In the first example the reason for going out too fast might have been that she wasn’t aware of it and that is one of the most important lessons I’ve learned while working with all these 5k tests. Many runners can’t tell the difference between a 44s lap and a 48s lap, especially when they are fresh. Take your time to do some short timed runs (maybe 100m or 200m) just before you start your race. And know exactly what pace is required throughout the race to have that PB. You will learn a lot about what the right pace feels like and you’ll be much more successful at pacing yourself for the fastest possible finishing time. Race Smart!