Monday, October 09, 2006

TSS/CTL/ATL/TSB

This entry is almost certainly going to complicate things a bit. People who use a Power Meter (PM) are going to read this and scoff at it. Those that don't are going to think it's too much. If you don't fit in those 2 groups, this might be useful. Or, it might sound almost useful, but a lot of fuss over what amounts to little more than riding your bike. On one hand I tend to see that point. But on the other hand I put a lot of effort into riding my bike these days. I want to make sure that I fall into the range that covers the following areas:
  1. I'm riding enough
  2. I'm not riding too much
  3. I'm not ramping too much
  4. I'm not slowing down or stagnant
  5. I'm allowing myself to rest enough
  6. I'm covering all energy systems evenly
This whole mess allows you to do that. How you put it together is where the art of training comes in.

Having said that, getting into TSS is a bit of a blind venture, since TSS is a PM specific metric used to measure your workout load. Defined as Training Stress Score (TSS), it is a number which represents the total amount of stress a particular workout puts on your body. By tracking this and watching both short & long-term trends, you can get a different view of how your workouts add up and why a certain day felt better than the others. Note that this does not differentiate kinds of stress. 10 low intensity points and 10 high intensity points are just 10 points.

If you really want to start at the beginning, you can read the link here to get a foundation for what power training is all about. As I write this, I do not own a power meter nor do I plan on getting one in the immediate future. Maybe next year, we'll see. For now, I'm skipping the actual power measurements and using estimated TSS, which isn't perfect but gives me a metric to use to judge my recent workout load. This is all about quantifying as best you can.

To get the long explanation on TSS/CTL/ATL/TSB you can go here. For those less inclined, the following will suffice:
  • TSS: Training Stress Score of a ride
  • CTL: Chronic Training Load, longer term "fitness"
  • ATL: Acute Training Load, short term "loading"
  • TSB: Training Stress Balance, "freshness" which equals CTL-ATL
That's it. I have a spreadsheet which calculates these based on the TSS score you enter. If you want it, email me (normZurawski@yahoo.com) and I'll send it to you. It has a nifty little graph which will give you squiggly lines and trends. Many people in the power forums refer to it as TSTWKT, or The Shit That Will Kill Them. Not very professional, no. But it is what it is. For a quick discussion of TSTWKT you can click here.

What to do with all of this? The only thing you need is your TSS. Everything else is calculated. How do you estimate your TSS? First, you need to read my blog on Energy Systems. These concepts are crucial to knowing what kind of workout you're doing. Absolutely crucial. If you don't have a reasonably firm grasp of these energy systems you can throw it all out the window.

It should be noted at some point in this discussion that if you're dicking around on the bike, or doing a group ride where you stop and bullshit with your friends at the top of every hill, that's not training. That's nothing more than JRA, or Just Riding Along. I say this to emphasize that in order for all of this to have some semblance of accuracy, you need to put a level of honesty and hard work into it. The reality is, some of these workouts hurt, especially L4 and above.

Ok, moving on from that little rant, where to go next? Well, assuming you have your levels worked out you can now reasonably guess what kind of ride you just went on. From there you can slap a TSS score on it, enter it in the spreadsheet, and leave it at that. Again, if you need the spreadsheet email me at normZurawski@yahoo.com and I'll send it to you.

It sounds easy enough, and really it is. There are a few things that are worth mentioning at this point.
  1. Structured intervals are going to be easier to estimate TSS
  2. Groups rides will be hard, nearly impossible
  3. Variable mountain bike rides are very difficult as well
  4. Low intensity endurance rides are fairly easy as well
  5. The trainer is an excellent way to base line this
So how do we take care of item #2/3? Personally, I don't go on group rides very often. If I do, I basically subtract the time spent not riding and then use my estimate for #3. Variable mountain bike rides get a score of 72 TSS/hour. Why? Why not? That number represents a point between L2 and L3. Since any off-road ride will be a mix of L1-L7, with much of it landing in L2, this represents a value right between L2 and L3.

But the number really isn't all that important. What's more important is that you generally find your off-road riding groove and stick to it. Basically, if that number is off by 25%, you want all your estimates there to be off by 25%. And when you're training for off-road events (like I am), you merely need to make sure your MTB-specific TSS totals slowly rise as your events get closer.

So what exactly is TSS? TSS = IF x IF x 100. IF is intensity factor. Here is how I break it down:
  • L2: IF~.8, 64 TSS/hr
  • MTB: 72 TSS/hr
  • L3: IF~.9, 81 TSS/hr
  • L4: IF~.95 (rest periods not included), 90 TSS/hr
  • L5/6: IF~1.0 (rest periods included), 100 TSS/hr
L1 isn't stress, so I don't count it. L6 is close enough to L5 to strap it with that level. And L7 work lasts for about 10 seconds and gets wrapped up in my MTB rides since I don't do L7 specific work.

A lot of this is discussion for the benefit of the reader. If you know your energy system levels and the numbers above, that's enough to move forward with the discussion. Of course, you need the spreadsheet as well. Then you need to stop reading, go out and ride for a few weeks, and start entering numbers in the spreadsheet. Unfortunately the numbers don't mean anything until you have about 6 weeks of data. If you've logged your rides you can go back and put in estimates. Otherwise you need to slog away for 6 weeks until you see where you are. Resist the temptation to go nuts in an effort to fill up your CTL. It'll only bite you in the ass down the road when you're burned out.

Now what?

Now you need to learn how to work with these numbers. Well, there's the rub. There is no generally accepted way to work with these numbers. This concept is relatively new and there are any number of ways you can work with this. Obviously, the goal is to get CTL as high as you possible. What CTL range do you want to be in? One coach on Cycling forums has his athletes at 55 CTL in October. It ramps up to about 70 by January. From February through September it ranges from 70-100. Peak areas end up in the 85-100 range. The hours come up to 7-11 in the winter, and 11-13 in season.

In one discussion with a respected sports scientist in the field, his estimate is that 150 is about the highest reasonable CTL you can maintain, with numbers in the 200 realm representing a level nearly guaranteed to blow you out of the water sooner than later.

But only focusing on CTL won't get the job done. Obviously the most efficient way to build CTL is to work at L5 and above. But if you know your levels, L5 is brutal, and after an hour of that you're ready to lay on the ground and sleep. So going the other way, if you have the time you can easily build your CTL using L2 workouts. By piling up loads of endurance riding you can get your CTL sky high. But then, you're just training yourself to go a long way, slowly. You need to build with a mix of workouts in order to be able to ride any reasonable trail/course.

I'll throw in here the way that Coggan classifies workouts in terms of total TSS accumulated:

100- low (easy to recover by following day)
100-200 medium (some residual fatigue may be present the next day, but gone by 2nd day)
200-300 high (some residual fatigue may be present even after 2 days)
300+ epic (residual fatigue lasting several days likely)

While I'm here, I'll also link the Coggan post for reference, here.

SST, or Sweet Spot Training, is a great way to raise your CTL. A good article is one by Frank Overton which can be found here. The basic idea is that after your first peak, your CTL has dropped significantly because of your race prep and taper. So it's easy to build up TSS with SST, but you also rack up a lot of ATL, which can put you "in the hole", so to speak. After this "reloading" of CTL, then you can take a little time up to come up for air, watch your TSB go positive, then hit the higher intensity stuff hard.

But this only covers a time frame between peaks.
One account which promotes SST training during the off season:

"Starting last November, I went cold turkey on pure L4 work for the 1st time since I started training with power. I decided to target the 0.80-0.90 IF range and see what my n=1 experiment yielded. Average week was ~12hrs, ~850TSS, and ~0.85 avg IF. I followed that base routine until around six weeks before our 1st TT in early May with the usual transition into L4-5 work.

(a) FT increased about 25W before I started typical 0.95-1.05IF L4 work
(b) CTL up where I wanted it (roughly 120 and I built somewhat higher)
(c) I set PB's this year for durations of 30-sec to 5-hrs and they were quite evenly distributed throughout the year. That was a big departure from the last 2-3 seasons where my last PB's would be in May and then a big gap until Sept/Oct. where I'd occasionally pull off a nice 1-5min PB.
(d) No 'dread' of training sessions throughout the winter as I'd typically get when pounding at the higher intensities. I doubt I missed more than a couple of sessions all off-season.
(e) No perceived or demonstrable fade in performance over the season. I know the word 'base' means a lot of things to a lot of people but I felt I had a great one."

L2-L4 workouts are essentially the same, in a way. They are all endurance training which you do at sub-threshold. L4 obviously pushes the envelope which is why you can only do so much of it. L2 is a lot easier, but it takes a lot more to get the same physiological adaptations. Basically it's a tradeoff between intensity vs. duration. So 60 minutes of L4 is "better" than 60 minutes of L3, but you can do significantly more L3. As you build, your time in L3 can easily get to the 3 hour realm, which will really boost your TSS totals. Compare that with what you get for an hour of L4.

Ok so that's SST, which is how I'm spending my off season between 2006 and 2007 because I want to drop pounds as well as get ready for the L5 and L4 blocks in mid-late winter. I'm also using that time to get myself used to riding at 5:00 am because that's the way it works out when you work in the city and you have a new daughter. Time is what you make it. I make it by getting on the bike at 5:15 am 3 days a week. I also need to make sure I can handle riding 5 days a week.

Coggan says that while you aim to get your hours in, you might also want to get on the bike at least 5 days a week. His contention is that spreading the training load over more days makes it easier to maintain your CTL and keeps your TSB from going too negative, ala the Weekend Warrior. After having dabbled in this Estimated TSS venture, I actually came to the same conclusion before reading this suggestion by Coggan.

Overall, the generally accepted CTL ramp rate is 3-8 points per week. Any more than that and you're probably going to be susceptible to injury and illness and so on. If you're starting from a low CTL, you may be able to build at a faster rate. But once you've established some sort of baseline, the 3-8 rule is good to follow. If you push for the high end of that, you may need to throw in a rest week every 4th week.

So there you have a plethora of random thoughts on this emerging and ever-changing subject. Ideally you want to build your CTL as high as you can. You also want to do this with a steady mix of L3-L5/6 work. You then need to fill in the gaps with L2 work which is how you teach your body to ride long distances. As your events approach, you want to back off so your TSB rises. This will cause your CTL to drop, but not too much if you don't taper/peak a lot. So the ideal way to present yourself is with a high CTL and high TSB. How you get there is up to you and is often a work in progress.

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