"Optimal Training Zone" - is staying -10 to -30 TSB a goal?

I was just looking at my PMC using intervals.icu and just looking at the time I was able to spend in the “optimal training zone” of -10 to -30 TSB, which aligns with SSB1 and 2 I did until the end of Feb, since then, I followed Sustained Power Build HV, SSB2 HV, Short Power Build LV (plus other riding), and now CX Specialty LV (plus other riding) and my TSB has stayed in the grey or fresh zones through all of these phases.

The biggest FTP gains for me came in SSB1 and 2 originally (which align with 2 successive 1 month periods where I’m almost exclusively in that green zone), and I was able to get a little more out of Sustained Power Build, but I was curious if maybe I’m not maintaining a high enough level of stress for a consistent amount of time like I did in base to gain maximum effect from the riding I’ve been doing since like the end of May going forward. Just to be clear, I don’t mean additional FTP gains, just other adaptations of getting stronger on the bike, so I’m in just in a state of staying in shape instead of really pushing myself forward. Interested in others’ experiences in managing their training stress, and of course I always appreciate those who humor me and my random questions!

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Is the “other riding” reflected in the PMC? IE do you have power for outside riding? Not all TSS is created the same. It looks like you used the winter to bump up your training load(CTL) pretty high with lots of volume and then backed off the time on the bike with the higher intensity intervals which is perfectly acceptable since CTL=/=fitness. Could you likely have benefited from some additional TSS to continue to ramp CTL? Probably if you had the time to do some LSD/tempo rides but not if you were just going to plug in extra interval sessions or more sweetspot work if it would compromise your recovery.

Yeah, all my riding (with power, including outdoors) is in PMC, end of June into mid July was family vacation so wasn’t riding as much, otherwise always over 10hrs a week, even on the low volume plans (in June all weeks but one were over 11hrs per and have been over 11 per week since mid July. I got really negative just now due to riding 150 miles on Saturday (425tss lol).

Was just curious if people try to keep that stress balance fairly negative for all their training blocks and if success in training blocks is correlated with keeping that stress balance in that so-called zone for a period of several weeks like I had during my base cycles. I mean, the more you build CTL, the harder it is to drive that stress balance negative without a lot more riding, either volume or intensity, which I guess is kind of the point that CTL lets you do crazy volume without needing loads of recovery, heck it took 10hrs of riding to get myself super deep with the TSB.

I actually use the -10 -30 and the .80IF (weekly) barrier as my guardrails when I’m “just riding for fun”.

If your CTL is reasonably high, this should be a safe TSB range and overall IF for a given block. Granted this is assuming you’re experienced enough to have a sensible schedule. While CTL =/= fitness, I think we can all agree that well built CTL maintained over time is a fair indicator of durability in an experienced cyclist. Point being, I’ve been doing a big Saturday (~100+ miles and ~9000ft) with hard efforts mixed in for the past 7-8 weeks. It tanks my TSB for the next day, but I’ve noticed as my CTL crests 100 and towards 120 I’m good for a few hrs on Sunday too. HRV and RHR tell me as much.

FWIW I don’t have a race, but I’m ditching fatigue with a couple easier weeks because regardless of how good I feel, I know the 120s will catch up to me personally if I don’t. Then back to your -10 to -30 and having fun on the bike.

That’s a big build; just be cognizant that this can roast some people, so maybe take yourself into “fresh” zone before starting the next block; it will help your consistency and love for training down the road.

it looks like your fitness hit 85 (?), which is solid for most people out there racing! but then the training became inconsistent and then really dropped off, so you shouldn’t expect to see more gains (altho a week after that initial drop, I bet your short efforts of 2m or less would be monster like (this is why crit racers taper more than road racers: rest is huge for anaerobic efforts).

I wouldn’t say the -10 --> -30 is a goal, but rather look at your fitness score in comparison to the form. And, use these metrics towards a goal, not the goal themselves.

Let us know how things go!


In searching, it appears it was Joe Friel who originally had the recommendation of staying within -10 to -30 TSB zone for optimal training https://joefrielsblog.com/part-3-training-stress-balanceso-what/

In this blog post he says “If you spend much time in this -10 to +10 TSB range your training is stagnant. Not much is happening.” It’s interesting for me in light of the fact that from Feb 26th through mid-April I followed Sustained Power HV and barely dipped below -10. I don’t know what evidence Friel has that training is stagnant in that -10 to +10 range, but my curiosity is piqued on maybe trying to plan my training next year to stay more within the -10 to -30 TSB range for blocks. Even doing SSB2 HV the 2nd time around from late April-end of May I was staying in that grey zone, so would be curious if Friel would say if I wasn’t maximizing that training block by not staying in that alleged optimal range and if he would have suggested some more TSS to stay more consistently in that TSB range. I’m headed into CX season and won’t be super focused on any of this and just maintaining fitness while racing every weekend.

How did your fitness signature change after the build block? Not just FTP but 20m, 5m, 1m, 30s power

Well, in Sustained Power and into the 2nd round of SSB2 I have my best 10min-2hrs. I did Wynne on Aug 6th and have some all-time 30sec-2min power based on that, so really the signature changes depends on the workouts I do. And the 4-5min range was set during Sustained Power Build during one of the workouts. I moved my FTP from 275-310 throughout winter to early spring (manual bumps, not via testing) and have kept it there since, so a lot of signature changes are just by virtue of increasing the target. I don’t do a lot of racing, and mainly endurance riding outside where I’m not necessarily trying to push for PRs, so I don’t have a ton of ways outside of prescribed workouts with ERG mode to really test the limits of various power durations.

Does intervals.icu allow you to keep historical record of your FTP? Strava doesn’t and the PMC is worthless because all TSS calculation is based on your current FTP setting (yes, it recalc all based on current). Second, Strava is based on PhysFarm Training Systems (with a sprinkle of TRIMP here and there) and not sure if the differences are sufficient thus making the recommendations not applicable (NP and xPower drifts significantly depending on VI). Use WKO or Golden Cheetah (version 3.4, 3.5 ditches Peaksware/Coggan and defaults to PhysFarm Training Systems and you’ll have to code it back in to speak the same language).

FWIW, I find TSB recommendation doesn’t work for me and I rely on ATL and CIL. But, that’s based on using FasCat training plans as opposed to TR (just getting started and will start first plan in Oct). FasCat’s plans are lighter on weekly IF, 0.7-0.78 as opposed to >0.8, but 1.5x-2x TSS (based on mid volume comparison). I’m cooked when my ATL spikes over 100 and CIL over 0.58ish, fatigued mid 80s/0.55. Haven’t done anything similar to TR plans so my tune may change.

Do you recover easily? If so you might want to play with the ATL constant. 7 day is standard/default. Move it down, less days, if you recover easy. Up for seniors. Can’t adjust my CTL & ATL constants on my free Strava account and suspect it’s the same for paid.

Here are my last 9 months. I followed a succession of plans similar to you by following SSB1 & 2 (MV)—with an FTP of 300—which looks really similar to your results for those two plans. However, I got derailed toward the end of April with an injury that really hampered my progress. I was on the verge of starting Sustained Power Build (MV), but I wasn’t able to train or really even ride hard for a good 6-8 weeks which is where you see a huge decline in my CTL for the entire month of May into June.

As you can see from Feb 1 all the way into May I was always in a state of -15 to -5 TSB outside of two rest weeks. Lately I’ve been doing a lot less structured training and more outdoor rides and piling on some harder 200+ TSS weekend rides which has cause my TSB to dip pretty low.

I haven’t done anything worthwhile in the last month, and am in that gray area myself. CX season is underway with unsanctioned mid-week races and I’m trying to get my ass on the trainer again to get back on that grind.

To answer your question, I can’t tell you what the optimal range is, but I can tell you that I’m a lot more tired now than I was in the midst of SSB1 and 2. Not sure if I’m any faster though.

  • Yes, among along with Weight and W’


Reading back my original post, I wish I had phrased it differently and more globally on Friel’s assertion, as opposed to focusing on my own PMC. It would be interesting to see how people feel like they did during a training block and correlate that with their TSB during that block, because now I really do wonder if maintaining the stress at a reasonable negative level is better in that it delivers more stimulus for a sustained amount of time and then the recovery weeks really consolidate the gains.

Looking back at some of my previous training phases throughout the last year Ill give what input I can and see if any of it is helpful.

On sept 24th I started SSB MV with an FTP of 282 after the ramp test.
My CTL on the same day was 67 with a TSB of -7.
I finished that training block with a peak CTL of 80 and a TSB of -20 before the recovery week.
Overall it felt very manageable for me and I felt that I had improved a lot so I decided to start the next block of base training with a high volume plan.
During the SSB MV plan I had been commuting ~20k a day and doing some weekend rides when the weather cooperated but I treated those more as recovery rides and tried to keep the IF and TSS on them as low as I could while getting in some distance.

For the start of SSB HV I tested at 300w, a great increase for me.
My CTL for that day was 73 with a TSB of 16.

I finished the HV training block missing 1 or 2 workouts in total (substituting the for outdoor rides) with a peak CTL of 115 and a TSB of -35. My lowest TSB of the whole block was -56
My FTP test after this was 314, another good increase.

Overall this was a huge increase in volume compared to what I was used to, however it still felt doable.
I had to place a huge importance on my recovery and nutrition so as to not dig a hole that I could not recover from.
Throughout the whole block I was sleeping 7 hours at a minimum and eating a huge amount of food.

I want to try something similar again this off season and see how it goes as I feel that I can manage a fairly high volume quite well and SSB seems to work for me in increasing my FTP. Ideally I will be able to continue the HV plans into the build phase and see how that treats me.
I was not able to keep the same volume into the following months unfortunately as work became quite busy and overtime really ate into my ability to train.


Thanks for sharing! I’ve been doing the high volume stuff for a couple of years, I’ve found my body handles is well, especially for sweet spot and even sustained build. But I think my CTL was high enough by the time I did SSB2 HV the 2nd time around in May that it might not have been enough stimulus for me. I’ll be really interested in seeing what happens when I get back to SSB in December. I might get back to subbing some lighter end sweet spot for endurance in my routine and get a more stimulus, but not at the expense of racing CX well.

Same for me here, im not doing a ton of proper training at the moment but hopefully as I get more time this winter I will be able to up the volume and see how it goes with the HV plans.

I do short power, and XCO specialties, and the normalized power numbers that strava spits out for those workouts are just plain stupid, so my performance management chart is basically worthless.

Training time seems to be the only thing that really works for me. I will not be renewing my strava premium account next year.

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It’s good that you’re prioritizing 'cross performance over CTL. A couple of seasons ago I was trying to maintain a CTL >100 while racing 'cross. I ended up going into races with -TSB and lacked any snap in the early laps. I could ride through people late in the races, but the front group was already gone.

Yeah, last year I was about 75 at end of August and the CTL gradually dipped into the 50’s by the end of the season, and it was a good season for me doing it seriously for the first time. I’m at about the same point CTL wise, I’m hoping not to let it dip as much, but it’s not a focus of mine, since huge CTL isn’t needed to handle the demands of a 40min event.

Freshness is much more important than overall fitness during the cross season. Trying to maintain your CTILA lot of pros will take a mid-season break and do a couple week block to build endurance back up, but their seasons go from September to Februrary—not something most of us experience. Given that most seasons in the US are at most 3 months, I think it’s ok to maintain fitness, but not expect it to increase throughout the season.

I’m curious how you’re planning on structuring your race weeks. This is something I’ve been thinking about. Looking back at last year I raced once a weekend (never more than one race) and commuted (weather permitting) during the week, and maybe squeezed in one day of HIIT or Sweet Spot. This season I’d like to be a little more structured so that I’m building my work capacity throughout the season rather than—like last year—just relying on whatever fitness I brought into the season and then one race for sustaining fitness.

Side note. I did a ramp test yesterday which was the first time since March and netted an FTP of 325 (previous test in March at the end of SSB1 was 300w) no structured training at all in the last 3 months. Just mid-week outdoor intervals, and some long hard weekend rides along with daily commuting. This was really surprising.

Well, last year I would do a combo of sweet spot and endurance during the week, I was racing every weekend and sometimes twice a week and had done all the specialty, so it was important to just stay pretty fresh and keep a certain level of intensity without sapping my legs ahead of the weekend races (and sometimes a weeknight race). Tallac and Geiger were regular parts of my rotation, often times twice a week.

I only did something like Apple Orchard or Megantic a couple of time, and I’ll see about keeping something in rotation to stay sharp, but by the time I finish specialty in 3 weeks I’ll probably have all the fitness I’ll have and I’ll just ride the wave through Dec. If I finish closer to a podium this season and get to a place where I might want to have something to peak for I’ll reconsider for the future, but I did ok with this last year and never really felt like I was losing fitness for my races between Sept and Dec.