Wednesday, March 11, 2009


I coach some pretty sharp people. One of them, a 64-year old cyclist, just asked me some great questions. He's getting at the heart of what training is all about. The questions were so good I decided to post them here. Note that he is talking about WKO+ software which I use in coaching all of the athletes with whom I work. He uses it also. Every week I send him charts from the software which provide my thoughts and comments on how his training went in the last week and how that may affect our training in the near future.

If you use this software you're aware of how powerful it is. If you don't use it much of this will be a lot of mumbo jumbo for you, I'm afraid. If you want to get a better understanding of this entire topic order a copy of Training and Racing with a Power Meter by Allen and Coggan. It will give you a much greater depth and breadth of what training is all about from an engineer's perspective. Of course, the very best way of understanding all of this is to train with a power meter and use WKO+ to anaylze it. You'll learn a lot not only about training but also about yourself.

But perhaps it might help you a bit if I tell you what some of the acroyms stand for:

TSB = Training Stress Balance. This is often referred to as 'form.' It has to do with the athlete being rested before a race (or not). It may also help us to understand when the athlete is moving toward overtraining as a result of overreaching, which is necessary to achieve high goals. When well rested TSB is positive or at least trending strongly positive. When not 'on form' TSB is very negative and/or trending strongly negative.

CTL = Chronic Training Load. Referred to as 'fitness,' this is a marker of one's training stress over a long period of time, such as 6 weeks. The higher the CTL the higher the athlete's fitness. It indicates that the athlete can handle higher stress levels. Stress (workouts) are the reason we train as it produces adaptation which we call 'fitness.'

TSS = Training Stress Score. This is the heart of the system. The athlete's TSS is calculated for every workout by measuring intensity and duration. Intensity is measured relative to the athlete's Functional Threshold Power (FTP) which is the highest average power the athlete can maintain for 1 hour.

ATL = Acute Training Load. I call this 'fatigue.' It is the athlete's short term, rolling-average TSS. It is generally averaged over a 7-day period.

Question: How much negative TSB I can take without overtraining risk? This is pretty relevant now as I have a pretty clear calendar for the next couple of months and can get in a lot of training. I see that I have been at negative 48 and 36 in the past few weeks and am now at -22.

[Joe Friel] It isn’t so much the depth of negative TSB that is the cause of overtraining as it is the breadth of negative TSB. So far the longest you have been at -25TSB is 8 days (Feb 25-Mar 4). At that point you got some rest and it bounced back up to a positive value. I know of one highly fit cyclist who stayed at negative TSB the entire season and continued to race at a very high level. He is unusual to be able to do that. He is gifted in that he can handle a lot of stress without breaking down. Mere mortals like us would probably wind up overtrained. The key to avoiding overtraining is to have frequent rest to shed fatigue. I try to do that for you about every 3rd week at most for about 3-5 days depending on what I’m seeing and hearing from you. This is very individualized. So far your travel schedule has generally kept us from going that long. So it’s been easy. With a long block of uninterrupted training it is very important that you honor the easy days and days off. Not only will this help to shed fatigue and thus avoid overtraining it will also make the quality workouts higher quality (meaning higher absolute intensities and greater duration at moderately high intensities).

Question: Also, you mentioned a target CTL of 80 before important races—I think I can get a bit above that but we will see.

[Joe Friel] Yes, it is certainly possible depending on how you respond to continued high training loads as you are moving toward now.

Question: Will there be a point at which I will do some all out efforts—I am really not doing any except maybe some of the sprint intervals.

[Joe Friel] I have been gradually moving you toward higher intensities and longer durations at high intensity. Please note the workouts on your schedule for March 13, 15, 18, 20, 24 and 28. These involve some “all out” efforts at different durations that will definitely overload you and create a lot of TSS and negative TSB. I think you are just now becoming physically able to handle this. Also note there are 3 days of rest Mar 25-27 while you are traveling to shed some of the ATL/fatigue from this stressful block of training. The week after that we’ll go hard for only a couple of days and then rest for 2 days before the next event.

Question: Regarding race preparation, what TSB do you think we should shoot for based on my schedule and do you think, at my age, ATL should be for 7 days or more or less?

[Joe Friel] The “science” of training right now is very much a trial and error. It’s really more of an art. I try things (like for the next 13 days) and see how your body responds. I’ve been doing that all along. From that I get a sense of the training load you can manage and make adjustments going forward based on your response. I expect within 2 years we will be able to 'prescribe' workouts using WKO+. At that point we will know more about how to use the data. It’s been around for such a short time that we are only beginning to scratch the surface with its potential. As for the duration of your ATL, I have not seen a reason to change it from 7. This would be a great topic of discussion for us, however.


At March 14, 2009 6:25 AM , Anonymous Anonymous said...

Excellent stuff; really helpul!

At March 15, 2009 7:45 AM , Blogger Dinger said...

Joe, I know I've asked you about this in this forumn before, but I feel very uncomfortable using this great tool (WKO+) and loading it with hard data from my PowerTap (cycling) and Garmin (running) that produces very accurate results in the software, then tainting it all with my subjective interpretation of my IF score for a swim to produce a TSS score for the session.

Sometimes it is hard to distinguish between a truly hard session, and one when I'm just not feeling all that well.

I think you guided me last time to perhaps guesstemate a TSS score by assuming 1 TSS pt for every minute in the pool. A descent rule of thumb, but we know that not all "minutes" are equal from an effort perspective.

Have you thought any more about this issue, or have a recommendation for helping to improve the quality of data on the swim that I input into WKO+?


At March 15, 2009 7:55 AM , Blogger Joe Friel said...

Hi Greg--Yes, estimating TSS can be a challenge. The 1 TSS point per minute gives you a rough guide, but it's obvious the workout could have been harder or easier than 60 TSS/hour. Here's a table I sometimes have the athletes I coach use when their device is in repair or whatever. The formatting may not work right in all layouts so you may need to play around with it to make sense. There are 3 columns - REP on 1-10 scale, avg HR by zone, and TSS/Hour. Hope you can figure it out ok.

Estimating TSS based on RPE or Average Heart Rate

(1-10 scale) Zone per Hour
1 1 (low) 10
2 1 20
3 1 (high) 30
4 2(low) 40
5 2 (high) 50
6 3 60
7 4-5a 70
8 5b (low) 80
9 5b (high) 90
10 5c 100

Example 1: A 30-minute workout at an average RPE of 6 would be a TSS estimate of 30.

Example 2: A 90-minute workout at an average RPE of 4 would be a TSS estimate of 60.

Caveat: By definition, a 100 TSS workout cannot last longer than 1 hour.

At March 16, 2009 4:05 AM , Anonymous Anonymous said...

Hi Joe,

Useful information! Much appreciated. Two questions, firstly how well do you think the Swim TSS calculation at works? Is it worth using or is your estimation method above better?

Secondly, regarding your comment about a 100TSS workout not being longer than an hour. I assume though that three hours at RPE of 6 giving a TSS of 180 is OK, just not more than 1 hour at RPE 10?

At March 16, 2009 7:04 AM , Blogger Joe Friel said...

Anon--Yes, I think that should work well for swimming. And, certainly, a TSS of 180 is quite reasonable. Not more than 100 'per hour' is because, by definition, 100 is all one is capable of doing in one hour. For example, with a power meter if you go more than an hour at 100 TSS then your FTP is set too low.

At March 16, 2009 7:08 AM , Anonymous Anonymous said...


Thanks for the clarification. I was not aware that a TSS of 100/hour was the defined maximum. That is a useful bit of information I had not seen mentioned before. Admittedly I am not yet all the way through Hunter and Coggan's book though...

Thanks again for your interesting and informative blog!

At March 16, 2009 7:46 AM , Blogger cory smith said...

Great info,very interesting

At March 16, 2009 3:38 PM , Blogger Dinger said...

Joe, thanks for the TSS estimator guidelines. I think it might help to have a framework like this.

As for Fitgerald's method, it seems a little unreasonable to apply for someone who does the majority of their swimming in a formal masters swim workout where there are sometimes several dozens of intervals in the session.

It also ignores the impact of doing anything other than straight freestyle swimming. Doing a non-freestyle stroke, kicking or drills would falsely reduce the calculated effort, where as swimming with fins or paddles might falsely increase it.

Joe's method above seems to be more broadly applicable.

Thanks again,

At April 6, 2009 12:37 PM , Anonymous Shane84 said...

I am a competitive distance runner using WKO+ and I was wondering if in addition to the RTSS I have from my runs(Garmin 405), do you recommend making up a TSS for strength training workouts when I input them into WKO+? Thanks.

At April 6, 2009 12:43 PM , Blogger Joe Friel said...

shane84--Thanks for posting. If you want to be precise about training then every activity in your life that provides a physical stress (mental also?) should be charted. That would most certainly include weight training. And the more challenging the weight training the stronger the argument to capture the data. Most don't simply because it becomes tedious.

At April 25, 2009 10:35 AM , Anonymous Shane84 said...

Thank you for your response. I also wanted to ask about TSB. I have had a negative TSB for well over a month now, and I am heading into an A-priority Race(half-marathon). Is this ok?

At April 26, 2009 1:42 PM , Blogger Joe Friel said...

Hi Shane84--Yes, it's ok to have a negative TSB for a month but you need to start raising it to positive by about a week til the A race.


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