The next discussion is a little more complex, and covers a lot of the discussion from the Stress Progression Chart. It’s crucial because the Strain Chart will allow you to understand not just what’s on Xert when you log in, but because Strain is also a field that you can monitor from a Garmin head unit through the Connect IQ apps. We can even use Strain values to build workouts.
Let’s start with a definition of Strain, per the Xert model:
While Stress (red/green/blue bars on the chart at bottom of this page) is the work done, Strain measures how difficult that Stress was to perform (red/blue/green bars in the chart at top). Sometimes reaching a wattage goal for an interval is easy. But depending on how much previous Stress you’ve been under, reaching the same wattage output can be extremely difficult, if not impossible.
Xert takes that difficulty into account and defines it as Strain. What this means is that if a workout is difficult and you’re able to accomplish the task, it will probably make you stronger. That’s how Strain works, folks. The harder something is to do, the more impact it will have on your fitness.
When you look at the Strain chart, you’re seeing what all that accumulated Stress is accomplishing. Strain is closely tied to MPA, or “Maximal Power Available,” which we’ve discussed previously. The closer your Stress is to MPA, the higher the Strain.
Like Stress, kilojoules of Strain are allocated into those Low, High and Peak buckets. These buckets make it possible to see where your Strain is focused.
When you ride easy and/or for a short period of time, you’re getting in Low Stress (overall KiloJoules), Low Strain (no hard stuff) workouts. But when you’re riding in a short, hard, maybe competitive race, Stress goes up, but Strain goes way up. Very high Strain scores are possible in competition, because you perform a lot of work closer to your MPA.
As I said at the beginning of this chapter:
Stress is where the energy you’re using is being spent, and Strain is how that spent energy affects your ability to generate more power, and ultimately as fitness.
At Online Bike Coach, we use Stress, Strain, Focus (green dotted line in the chart at top) and Strain Score), to help you progress at a pace that is appropriate for you, and to focus on the types of intervals and efforts that will help you achieve your specific goals.
Next time , we’ll take a look at your Xert Performance Management Chart (XPMC), which lets you see more clearly, how each workout’s Stress, Strain, and Focus fit into the bigger picture of your fitness and progression.
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