You know how it can take an extreme example to prove a point? This is what happened to me with the point that going out too fast in a race is not the most effective way to run a race. Going out too fast in a race is a rookie mistake. It is a rookie mistake that even after running for 10 years, I still make. When racing, I often find myself running faster than planned during the early miles; I’ll think about banking time knowing (when I say “knowing” I mean “incorrectly assuming”) fatigue in the latter miles will force me to slow down. My reasoning for banking time is that during the latter miles, I will be able to cash in the banked time and still meet my goal. While I can tell myself this strategy is successful because I meet my subjective goal, it is clearly an anecdotal fallacy; there is a ton of evidence supporting the claim that running a positive split (running the first half of the race faster than the second) is not the most effective way to meet your racing potential.
I’m not going to go into the data supporting negative splits but if you’re interested, this link provides a great analysis of some race times and allows you to draw your own conclusions about successful pacing strategies. If you typically run a positive split in your races, don’t feel bad; you’re in good company (and the massive majority). Why? It’s really hard to run a negative split!
Check out this Runner's World article: What World Records Teach About Marathon Pacing
My unintentional experiment came on a day I had planned to run 13 miles. I have recently been trying to slow my roll, to run the majority of my runs easy, rather than at the medium pace that I would usually fall into.
Running slowly is like a breath of fresh air; it’s fun (and easy). I like the idea of the 80/20 running plan (80% of your mileage is an easy effort, 20% is a medium to hard effort), and especially the data and scientific support behind it. FYI, It’s likely I have been encouraged by Matt Fitzgerald’s book, 80/20Running, which I am currently reading.
Although running slow is fun and easy, I still need to do some hard work to harness my full potential (I cringed at writing that but I’m leaving it in!). That was my thought as I set out to keep my heart rate (HR) below 140bpm (70% MHR) except for the 5 X 0.75 mile intervals I wanted to do. By the way, this run started at 10am with a temperature of 89F (31C). It was HOT! I warmed up for three miles before starting the intervals. I noticed my HR was not going under 140bpm during my recovery (0.25 miles) but I wasn’t worried; I had several miles to run after the intervals in which I would run in the easy zone 2. However, much to my surprise, my HR was extremely hard to get into zone two after the intervals were done. I really slowed down too! It want’s until I slowed to a walk that I could get my HR into the mid 130s. A lot of runners don’t like to walk (I am one of them), even if their goals would be better served by doing so but I think that comes down to ego (fodder for another post). Anyway, after my short walk, a very slow trot kept my HR in the range I wanted but it was several miles before I had recovered enough where I could speed up without putting my HR through the roof. Below is a graph of my pace and HR.
So, what did I learn from this workout? Well, nothing I didn’t already know but rather, something I chose to ignore. Recovering from a hard effort take longer than I thought! If I were racing a long distance, I would have jeopardized my race, or at least my race time, by burning through my glycogen stores so quickly. Then there is cardiac drift which is the normal phenomenon where your HR increases throughout your run (exercise session) although your speed remains the same. Even if you don’t increase your effort, your HR increases. If you raise your HR too early it has nowhere to go. Your effort will, obviously, be unsustainable. Although my interval workout and racing are not exactly the same, the lesson I learned is if you want to meet a certain goal (time, HR), correct pacing is the key to success! Deviating from your race/workout plan can lead to goals not being achieved.
Run hard when you have to, run easy when you don’t.