How low is too low for TSB?



liversedge

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Jun 28, 2004
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I have spent the last 6 weeks getting back into form, ready for winter training. After a period of almost 12 months without any training. Prior to that I was doing hard 5hr rides most weekends and 11-12hrs of structured training a week and my peak FTP was about 290w. I am not a racer.

I didn't seed my CTL when I got back into training, I figured I was in pretty poor shape and started from zero. After a month got to a CTL of 45 and had been liberal with rest days. I started to up the intensity and keep an eye on my TSB, RHR and general fatigue. My goal being to get my FTP to around the 260 mark and work on getting my CV system restarted.

I have found that a TSB of -50 or worse is about the time I need to take a rest of more than one day and that at -30 I should take it a bit easier taking perhaps a recovery ride or something.

This has lead me to wonder -- how low is too low for TSB? As you become better trained can you do more work with less rest? What do you guys here think? How low have you taken your TSB? Did you get any adverse effects?
 
Hi

liversedge said:
I have spent the last 6 weeks getting back into form, ready for winter training. After a period of almost 12 months without any training. Prior to that I was doing hard 5hr rides most weekends and 11-12hrs of structured training a week and my peak FTP was about 290w. I am not a racer.

I didn't seed my CTL when I got back into training, I figured I was in pretty poor shape and started from zero. After a month got to a CTL of 45 and had been liberal with rest days. I started to up the intensity and keep an eye on my TSB, RHR and general fatigue. My goal being to get my FTP to around the 260 mark and work on getting my CV system restarted.

I have found that a TSB of -50 or worse is about the time I need to take a rest of more than one day and that at -30 I should take it a bit easier taking perhaps a recovery ride or something.

This has lead me to wonder -- how low is too low for TSB? As you become better trained can you do more work with less rest? What do you guys here think? How low have you taken your TSB? Did you get any adverse effects?
I'd not normally want to be seeing a TSB much below about -25 for any extended period at all but then perhaps I'm just a bit of a girlie :)

I think a very low TSB for a day say after a really big training effort at the end of a rapid CTL build before tapering for an event for example is Ok. That is as long as it doesn't push someone over the edge and I would think should be reserved for someone who is well trained and coming to the end of a CTL build before tapering to bring on a peak in form, which is not what you are doing I don't think.

I wouldn't want a TSB is the -50s if I was returning to training, TBH I just wouldn't see the value in it but I guess it might work for some? I'm of course assuming that the numbers are all "correct", which may not be the case if there isn't a lot of recent training history going into the calculations.

Cheers,

PBUK
 
liversedge said:
This has lead me to wonder -- how low is too low for TSB? As you become better trained can you do more work with less rest? What do you guys here think? How low have you taken your TSB? Did you get any adverse effects?
I have gone as low as -85. Generally, when I get below -30, I am quite tired. Below -40 and I often feel like I am near death. I have a hard time concentrating, my brain feels tired, my body feels pretty tired and sore, I may be irritable. I may need very strong coffee just to get through the day. Extra sleep is very important at these times or I get weird hormonal stuff going on.

I don't know of any long-term adverse affects to low TSB. A certain TSB will feel a certain way depending upon CTL (and thus ATL as well) and the composition of what you have been doing up to that point. Obviously a certain training stimulus will result in a higher TSB if your CTL is higher. This makes sense - "the more you train, the more you can train".
 
I've just come off a -98 TSB though this wasn't intentional. I just didn't ride this year (~600 miles since Nov, 07 and prior to last week) due to a job promotion and then had to ride a 4 day/380 mile charity ride. After back to back centuries through the hills of southern Indiana, our 3rd day was a brutal 135 mile mostly flat day. The last day is only a 40 mile day, but was very "spirited". This is something I created six years ago to support a local charity and have been doing every year since.

It kicked my butt badly since we didn't have any significantly weaker riders in the group and I ended up doing a great deal of pulling at 75% - 90% of estimated FTP for long periods of time, not to mention the hill sprints I occasionally participated in.

Not really the example you were looking for, I know. For 3 days after the ride I woke up at 2:30am every night completely drenched from head to toe in sweat...not sure if related, but it definitely didn't feel "normal". I'm now fighting off a sinus infection a week later.
 
liversedge said:
As you become better trained can you do more work with less rest?
Yes. TSB is basically the difference between what you've done the last couple days/weeks vs. what you've done the last couple months. If you've been training at high volumes for the last few months (ie, have a high CTL) then a couple long days of riding won't produce the same negative TSB as it would after a long period of downtime.

As your body gets more accustomed to higher the training load (ie, CTL rises), it can absorb a few hard days much more easily and that's why TSB doesn't spike negative as readily.
 
liversedge said:
How low have you taken your TSB? Did you get any adverse effects?
I had some time off of work and increased my riding from about 10 hrs. to the low to mid 20 hrs. a week. My TSB was between 80-95 for a period of 3-4 weeks with no adverse effects. I ate clean, took supplements, and napped daily though. In a matter of days of returning to work I got a serve cold that lasted over a week. I believe, in my case at least, the immune system was comprimised. For the 13 percent increase in FTP it was worth it to me.
 
I would qualify that a -50 TSB after L2-L3 rides is not the same as a -50 TSB after L5-L6 training sessions. The former being somewhat tolerable, while the latter being close to unattainable. I thought I'd mention that before we're all tempted to start bragging about our "fatigue tolerance". ;) :)
 
Piotr said:
I would qualify that a -50 TSB after L2-L3 rides is not the same as a -50 TSB after L5-L6 training sessions. The former being somewhat tolerable, while the latter being close to unattainable. I thought I'd mention that before we're all tempted to start bragging about our "fatigue tolerance". ;) :)

That is certainly true, though I find any dip that low tough.
The issue I have is that with limited training any ultra event will occassion that type of TSB dip since we are talking about a ride of 600-800+ TSS ...
 
Piotr said:
I would qualify that a -50 TSB after L2-L3 rides is not the same as a -50 TSB after L5-L6 training sessions. The former being somewhat tolerable, while the latter being close to unattainable. I thought I'd mention that before we're all tempted to start bragging about our "fatigue tolerance". ;) :)
Did I say that?
Steve_B said:
A certain TSB will feel a certain way depending upon CTL (and thus ATL as well) and the composition of what you have been doing up to that point.
 
Piotr said:
I skip over the eloquently worded parts and focus on the numbers and smilies. :D
I know for sure you are joking when you wrote "eloquently worded". :)
 
liversedge said:
This has lead me to wonder -- how low is too low for TSB? As you become better trained can you do more work with less rest? What do you guys here think? How low have you taken your TSB? Did you get any adverse effects?

Comparing TSB between individuals is analogous to comparing HRs. The individuals may be at different CTLs and differently set ATL time constants, for example, making comparisons invalid. Even within the indivdual, interpretation of TSB will vary -
a -50 with a CTL of 50 will likely feel less fatigued than a -50 with a CTL of 120
a -20 following 3 hours of SST will likely feel different than -20 following 10x 1min @L6
a -30 following a couple of short nights of sleep will feel different than -20 following a couple of nights of great sleep

Consequently, as PMC indicators go, rather than solely monitoring TSB as a fatigue indicator, some advocate putting a bit more weight on CTL ramp rate (not exceeding a CTL ramp of more than 5-8 per week period).
 
So I think you are saying that TSB should be considered in relation to recent training load (your ramp up) and individual fitness or form i.e. ATL and CTL - and yet surely that is exactly how it is calculated?
 
liversedge said:
So I think you are saying that TSB should be considered in relation to recent training load (your ramp up) and individual fitness or form i.e. ATL and CTL - and yet surely that is exactly how it is calculated?
You got it. So, I expect you can now answer your own question:

If CTL is higher, then staying within a given (negative) TSB means that one can tolerate a much higher ATL.

It should be intuitive that someone who hasn't been training at all is going to suffer more (and longer) from a 300 TSS ride than someone who's been training regularly for the last 6 months.
 
So how low is it safe to go?

1) Should it be hard and fast, say no lower than -60?
2) Should it be a rule of thumb say, no more than CTL * -1 ? or CTL * -2 ?
3) Is it down to ability - say CTL*-1 for a relatively untrained rider moving to CTL * -2 for a cat 3 ... * -4 for cat 1 etc etc ?

I guess we all work it out for ourselves by pushing our luck and getting a chest infection - kind of like seeing how fast you can corner at before crashing :mad:
 
I'd expect most folks who train regularly (ie, 3+ times per week) to start experiencing flagging motivation or lower confidence that they can do a quality workout at around -20 TSB. Below -30 TSB I'd expect there to be serious feelings that a rest day is in order. I'm talking about the TSB on the morning of the workout day, not TSB at the end of the last workout if it was a day or two ago.

I wouldn't say those values represent the edge of the "safe zone," but when one might start questioning "how long can I keep going at this level and still have productive training?" The goal is long-term productive training, rather than seeing how hard we can push the envelope.

As has been mentioned above, the absolute values (-20 or -30) vary between individuals and depend on nutrition, rest, training intensity, etc.

Folks that ride less frequently are going to have much bigger swings because they have rest days naturally built into their schedule. If they do long rides on weekends and see a -60 TSB, then they're still back above -20 by mid-week if they rest.

Personally, I use TSB as an indicator of how I might feel on a given day and might swap training days if I see a mismatch (ie, low TSB on a day when I've scheduled high-intensity training). For longer-term health I look at ATL (fatigue). I tend to notice health repercussions when ATL approaches ~150, so I try to stay well below that level. Early season, when CTL is 30-40, I'll shoot for 50-70 ATL (keeping TSB around the -20 to -30 range). Later in the season, when CTL is 70-80, I can push ATL up to 90-110 without having issues of flagging motivation or inability to complete workouts.

Hope that helps. :)
 
frenchyge said:
I'd expect most folks who train regularly (ie, 3+ times per week) to start experiencing flagging motivation or lower confidence that they can do a quality workout at around -20 TSB. Below -30 TSB I'd expect there to be serious feelings that a rest day is in order.
Thanks for this bit of insight because it puts into words what I've experienced over time. When I first started using the PMC I would often dig a deep hole for myself w TSB > -50. This year I've kept my TSB in a tighter range. My low for the year was -40, but my operating range has been roughly -25 to + 17.

I made a conscience effort to build CTL more slowly this year, and the result is I haven't felt as tired and burnt out as in years past. At the same time I've been able to make significant gains in FTP this year, which is encouraging, because I thought that I was at my genetic ceiling at the end of last year.
 
IMO, if you're regulary seeing > -30/-40 TSB, you're either:

1. "Re-seeding" your PMC, in which case the numbers don't really mean that much until they've settled in, or:

2. Risking over-reaching by trying to load too quickly on one or two given days each week. Spreading the TSS throughout the week will keep the TSB in a more narrow range while providing the overall CTL increase you're probably looking for.

Personally, I find it easier to pay attention to an increase in the actual rolling 7 day TSS avg. I can look at a week of workouts on the calendar and know how much TSS it will be, and compare that to my CTL to know if it's going to be a good steady increase. I'll also see if I'm going to have a significant spike in the 7 day average that might jeopardize training effectiveness on following days.

Managing it that way, I rarely see TSB below -30.