Seiler 4x8 workout questions

So, I did this 4x8 workout! Not Hard, not easy, just boring but I have a few questions: Why does the peak power curve slope change during the last 8 minute interval but during the first 3 intervals , the slope is the same!!!. Yes,it was a little harder but Xert doesn t know because apparentjly does not analyze the heart rate ( another question, why doesnt the heart rate get trended???). my HR ( from my Garmin connect trend was a little higher)
Another question: why does xert always calculate the TP as 193 regardless of whether the workouts are eaay or not. I evem hace a 1 min ( by mistake) workout at TP of 193! Img_5400

Your 4th interval was harder than your first 3. You can verify by looking at the average wattage. Xert knows what’s happening from your power and doesn’t use (nor require) your HR data. Your TP is 193 independent of your workouts. You can try a long interval at 193W for yourself and see how easy it is to sustain.

OK! you got me on that one! i actually raised the intensity that xert had at 213 to 218. then I said: no, let me move it back to 213 and I did, but apparently either xert didnt download the vaue to my kicker or my kicker ignored it. Now i understand wht my HR went from 152 to 156! Anyway, i actuallly dif a harder workout!

If that’s not a hard interval set, your threshold power is too low. It should be pretty close to the best you can maintain for the average of all four intervals.

Because the 4x8’s are based on TP, some might find them easier than others. Problem when you’re using % for interval targets above TP.

That was literally what Dr. Seiller said when I heard him mention the interval set. Something along the lines of “if you tell an athlete to do 4x8min (with 2m recovery) as hard as and as consistently as they can, they’ll end up at X% of VO2max power for an average for the four efforts.” It’s 32 minutes of work above threshold, so it taxes both the aerobic and anaerobic system, so at the proper power level, they’re very hard by definition.

It’s an academic exercise to map out the max 4x8 minute effort with 2m recovery based on their Fitness Signature using the Workout Designer. Based on their FS, the %TP will vary. Frankly, there is nothing special about them being 8 minutes over 4 or 16 minutes. The workout definition has more XSS coming from the 4x8’s but you could change the durations / rest-intervals to make the higher intensity from the 4 minute intervals provide more XSS. Likewise, a slightly higher intensity in the 16 minute intervals would yield more XSS than those in the 4x8’s. You can play with this using the Workout Designer.

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It’s not academic when you go out and do it. It works out to be 108% FTP if you make the typical assumptions about the relationship between Vo2max and FTP.

Based upon the Seiler study, we estimated it at 113%. See

Well, everything changed yesterday. I created a workout 3 min increments starting at 45 w up by 30 W anf finished at 285. After 36 min of pain, xert recalculated my TP at 206 . My previous value was TP=195. So, now if I did the Seiler workout , each interval would be at 233 Watts , which I really dont think I can do ( at least mentally) I feel that I could do 233 Watt which then divided by 1.13 would give a TP of 197. Does any of this, make sense. ( btw, im 137 lbs, 68 age)

Congrats on the Breakthrough! Keep up the great work … and yes workouts will get harder after a breakthrough that raises your fitness signature parameters.

Thanks … but it’s a double edge sword!:blush:

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I think I could have done better , had I not ran 6 miles before with 6 1/4 mile intervals at 6;30 pace! Next time I’ll do it rested!

But with Xert I guess it would be the “same” to find a interval workout with similar levels of low/high strain to get the same benefits? Or at least maybe keep the time ±2 to 3 minutes around 8 min? (guessing here, please correct me if wrong)

The software doesn’t presume anything else. It doesn’t infer any other benefits exist except those that are quantified by low/high/peak XSS.

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