The Importance of Proper Pacing - A Case Study

Good Morning Athletes,

Today, I’d like to talk to you about the importance of proper pacing in your race strategy. I’m sure you’ve all heard it time and time again, but implementing it is a much different story. I’m hoping that today’s case study will demonstrate how incredibly important this is to your race strategy and ultimate success.

First off, how many of you have started an interval feeling strong and steady thinking “I can hold this effort for the whole interval, no problem” only to start degrading and struggling half way through. There is a time and place for these types of intervals (however, we start out at MAX and expect our effort to degrade over the course of the interval), but this is not the mindset to take into racing or steady state intervals. It takes a lot of mental discipline to hold yourself back for the first 1/4 or even 1/2 of your race while you feel fresh and strong. In triathlon, our mental discipline has to be even stronger because not only do we have to pace the race, but we have to pace each and every discipline in-and-of-itself. It’s not uncommon to start your run after a long bike and your pace is SIGNIFICANTLY faster than what is maintainable for the entire run leg (let alone what you trained for). For a very long time, I tried to convince myself that I should use the speed I had while fresh at the beginning because there would be no way that I would get that speed back at the end of the race when I was tired. I was wrong, let me show you why.

This is a, shall-I-say, unfortunate and unexpected case study. I am going to present data from two 5km races in my recent training block. This was me screwing up, not a purposeful experiment. Learn from my mistakes. These races were separated by two weeks of training but it was not a significant time frame to make large fitness gains in between. My fatigue and fitness were almost exactly the same based on the mathematical modeling I use to determine fitness and freshness for racing.

Figure 1 - Generalized data from my first 5km race. This includes a lot of data but most importantly Power (yellow), Cadence (Green), Heart Rate (Red), and Pace (Blue). *Click to enlarge image

Figure 2 - Generalized data from my second 5km race. This includes a lot of data but most importantly Power (yellow), Cadence (Green), Heart Rate (Red), and Pace (Blue). *Click to enlarge image

Above, you will see the overall general data gathered from both my first and second 5km races. At first, they may look very similar because the differences are subtle but highly impactful. The first thing that I should point out is that the course is the exact same, as you can see with the dark grey shaded elevation in the background of the charts. Power is the measurement of force x velocity and is a direct measurement of the effort that I am putting into my running. Some of this effort is going toward forward movement, some is going toward vertical and even horizontal movement but it is a direct measurement of the overall effort that I am doing. If you look at my power, you will notice spikes and valleys typically consistent with climbing and descending on a rolling course but… if you look closely, you will notice that my power is significantly higher at the beginning of my first 5km race. For the first 5-7 mins, my power is about 5-10% higher than my target effort. Put simply, I went out way too fast. I felt good and strong and thought I could maintain this effort for 3.1 miles… Again, I was wrong. The second thing I want you to notice is my heart rate (red line). I quickly reach my threshold in the first race, where I plateau until about 1.5 miles into the race (this portion of the race was absolutely MISERABLE). In the second race, I have a much more gradual increase that continues practically through the whole race… remember this point, because I will come back to it.

Let’s look a little closer at some of the power data. In the following figures, I have broken the race into four parts (the way I usually recommend pacing a race). The first 1/4 should feel comfortable, the second comfortably hard, the third hard like you may blow up, and the fourth… well you can do anything for the last 1/4 because you know the finish is there.

Figure 3 - Power data broken up into four parts of the race (0.775 miles) of my first 5km. The first quarter of the run I average 286W (my goal was 267W). You can notice a steady decline in power over the course of the race (Q1 - 286W, Q2 - 267W, Q3 - 262W, Q4 - 254W). This is not ideal pacing, this is holding on for dear life. *Click to enlarge image

Figure 4 - Power data broken up into four parts of the race (0.775 miles) of my second 5km. Here, you notice something very different. My first quarter I held an average of 269W (my goal was still 267W). Not only do I hold consistent power through the entire race (even improve in the last half, also known as negative splitting) but I felt much stronger in this race. (Q1 - 269W, Q2 - 269W, Q3 - 270W, Q4 - 271W). *Click to enlarge image

What was most noticeable for me between the two races was my overall sense of effort. The first race was an absolute disaster in terms of mentally and physically feeling like I was struggling. I wanted to give up every 0.1 miles and it took everything I had not to. The second race however, I felt great. I felt comfortably uncomfortable and strong right up until the end for my final surge. A night and day difference. As I struggled to hold 254W in the end of the first race, I was holding 271W in the second. A significant difference.

Finally, let’s just take a quick look at some indicators of fatigue before I summarize the race results.

Figure 5 - Fatigue indicators of Race #1.

RE - Running Effectiveness, HP - Horizontal Power, FP - Form Power, LSS - Leg Spring Stiffness, Pwr - Power, GCT - Ground Contact Time, Vertical Oscil - Vertical Oscillation, Impact G’s - Ground Force upon Landing.

*Click to enlarge image

Figure 6 - Fatigue indicators of Race #1.

RE - Running Effectiveness, HP - Horizontal Power, FP - Form Power, LSS - Leg Spring Stiffness, Pwr - Power, GCT - Ground Contact Time, Vertical Oscil - Vertical Oscillation, Impact G’s - Ground Force upon Landing.

*Click to enlarge image

As opposed to summarizing all of the data in these tables, I’d like to draw your attention to Power, Horizontal Power, Ground Contact Time (GCT) and Cadence. This is just a subsection of the data but an important one. What I have done in these tables is compare the first half of the race to the second half of the race to see if there is any degradation to indicate fatigue. In terms of power, I had a 7% degradation in power from start to finish in race #1, pretty significant. In my second race, I actually had a 0.5% increase in power. Horizontal power is the percent of my total power that is going towards moving me forward (the important piece). In race #1, I had a degradation of nearly 3.5% meaning I was no longer as effective in running forward, you can see this in my vertical oscillation which increased significantly in race #1. In race #2, my horizontal power actually improved and my vertical oscillation decreased as I came down the home stretch. My GCT increased in race #1, meaning I was spending more time on the ground and had to “create” more power, where as in race #2, it decreased by 2% allowing me to recycle more energy like an elastic. Finally, my cadence slowed significantly in the second half of race #1, whereas, you guessed it, it actually improved in the second race. All of these indicate my level of fatigue was not sustainable in race #1 and I just broke down prematurely.

So after all of this, I am sure you are wondering what the difference was in the actual race results. Well, I finished in 21:55 with an average power of 265 (close to target but not quite) in Race #1. In Race #2, I only averaged 5W higher with an average of 270W (higher than my goal). My time, however, was a 21:08. In a 5km race, that is a significant difference in finishing time… especially at 8000ft where oxygen is a pricey commodity. This was in a ~20min 5km race, imagine extending this out to a 2-3 hour olympic distance triathlon or any of the IRONMAN distances… it would be absolutely catastrophic.

There are many take aways from this case study but the first, is that your absolute effort (or WATTS) may not be much different, but if your form and effectiveness don’t break down… you will be significantly slower… so watts doesn’t necessarily translate perfectly to speed… Efficiency AND power does. Secondly, think about why I was wrong in my old ways of thinking “use speed while you feel good”. Remember before when I said “remember this point”… Where my heart rate plateaued in the first race but gradually climbed in the second. If you use that speed early in the race when you’re fresh, you play the game of “hold on for dear life”, the real problem lies in the mental not necessarily physical state… well a bit of both as you can see from fatigue indicators but I’m exaggerating to make a point… When I get that “hold on for dear life” too early in a race (or interval) I have to be able to mentally overcome the desire to quit or slow down for a very, very long and difficult time… However, if I save that feeling for the final kick in a race or interval… I know that finish line (or rest) is coming and it’s much easier to mentally push through that road block.

I hope this helped demonstrate the importance of holding back and pacing in your workouts and races. If you don’t believe me, I recommend you trying it yourself. Next time you start your run leg in a triathlon and you feel good so you start to push the pace, I hope you think of this article and dial it back so you can finish strong and happy with a new and well deserved PR.

Want to know a cheat code in proper pacing on the run, check out our blog post on the stryd power meter here!

Happy Training and Racing Everyone!

- Coach Tom

*Data was gathered with the Stryd Running Power Meter that can be purchased at www.stryd.com. Coach Tom is a Stryd Coach but does not get any financial benefit from the sale of devices.