Workout Prescription Question

I’m looking at the workout: SMART - Hold Me, Thrill Me, Kiss Me, Kill Me, but this question applies to any SMART workout.

How do you guys arrive at the 170 XSS per hour x 3 minute as a prescription? Is this as arbitrary as a % of FTP type of workout?. If not why?

Thanks a lot

Good question!

The intended Focus of the workout will determine the XSS value & interval length. In general, the higher the XSSR, the shorter the interval.


XSSR is determined for every athlete according to their unique fitness signature & how they fatigue. While 170% FTP can easily be drastically different stimulus for 2 different athletes, 170 XSSR will always be comparable. You can verify this yourself… open the workout in the workout designer, change the signature variable(s) and then click the ‘refresh’ button and see how the interval changes as you adjust the signature.

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Thank you Scott. Using this workout as an example, the focus is GC Specialist 8:43. Please walk me through the construction, I’d like to learn how to do it myself. In this case, do you start by fixing 3 min, and then how do you decide on the XSSR?, Why 170 and not 150 or 190?