Measuring intensity

Date: 3/23/22
Training Day: 108
Miles: 4.1 (treadmill)
Time: 60 min
Shoes: Xero HFS

How It Felt: Another awesome, easy run! On previous runs I upped my pace as far up as I could go without my heart rate going over 140 bpm, but this time I just kept it super easy. My heart rate stayed in the 130s, and I felt great.

Commentary: This would have been a great day to run outside after work. But we’re heading to Boise this weekend, so I wanted my evening free to get all my stuff together. And my husband and I grilled hamburgers for dinner, which is way better than a run no matter how much I enjoy running.

On Friday I have an appointment at the Boise State University Human Performance Lab to get my lactate and ventilatory thresholds measured. My Garmin tells me what it thinks my lactate threshold is, but how accurate is it? Getting a legit lab test will be far more accurate. However, a part of me wonders if I should really be training by heart rate, or by power or pace instead.

Not very impressive, but neither is my running these days, to be fair.

Although I have yet to start the 80/20 book because I’m a slug, I have been perusing the website. They recommend power or pace because heart rate is dependent upon a lot of different factors like stress, sleep, temperature, when you ate last, etc. I know this to be true from personal experience, and sometimes I get frustrated when my heart rate is higher than normal for a given pace.

The 80/20 website has a guide for determining your threshold pace, heart rate and power. After my lab test I might look for a track to do the pace test. Since I’ll have my LTHR, the test should be pretty straightforward – warm up, play with pace to reach LTHR, run at that heart rate for ten minutes, and the average pace is the threshold place. But even the article says that pace isn’t the best to go by either because it’s basically useless if you’re going uphill or downhill, which trail runners do a lot.

This means power is the best measure of intensity. And I really like the way they described the relationship between power, pace and heart rate:

Horsepower (power) is the output, and represents actual work performed regardless of terrain, grade, or environmental factors. Your speedometer (pace) indicates the speed, or outcome. Your engine temperature (heart rate) represents how the car is responding to the output and environment. During a hilly ascent, the output (power) might be high, but the outcome (speed) might be low. On a hot day, the engine temperature (heart rate) might be very high even when stopped at a light with almost no output and zero outcome.

About a month ago I toyed with the idea of buying a Stryd power meter. I decided not to purchase one because the membership/subscription thing reminded me a lot of my Fitbit. You get six months free where they woo you with all these extra features, but if you want to keep them you have to pay a monthly fee once the free trial expires. Now I might reconsider purchasing one.

I know I’m likely nerding out on my running way too much. There are probably folks out there who are thinking just run and have fun! But I do have fun when I run, and I also have fun nerding out. And my nerding out could make me a better runner. And could being a better runner make running more fun?

Training Journal

Christina View All →

Endlessly seeking adventure.

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