Fitness/Freshness vs Actual Performance
 

Last month I started a one month FTP plan to see if I could improve my times on some shorter local climbs. Per plan, I substituted my three 40 mile per ride weekday climbing interval sessions down to the plan's 15-20 mile per ride combination of endurance, over/under and interval sessions. My weekend rides also dropped in overall mileage. Over the month, I noticed with growing concern that my Strava 'fitness/freshness' score as measured with power meter and heart rate plummeted from about 115+/- (whatever that means) down to the low 80s. But I stuck with the plan. Yesterday, despite waking up with a mild cold and sore throat and feeling like crap in general, I still managed to PR two 10-minute climbs, knocking roughly 25 seconds off each. So...exactly how relevant/useful to training is this nebulous fitness/freshness score. Judging by what mine has done over the last month, I should have been walking up both climbs by half way up.

Keith

115+? That's pretty high. Maybe you were really overrreached and scaling back allowed you to hit more specific work?

I don't know, but to throw out a (potentially useless) comparison, my CTL hasn't hit over 103 in 3 years and I'm riding 9,000+ miles a year as a Cat 1. 1 can't even handle 100+ for too long, and typically hover in the high 90s.

In any case, I can take a couple of weeks off, have CTL drop in to the 60s, ride for a week or two and get it back in the 70s and still crush a local KOM. But that would be a one off effort. A higher CTL, however, allows me to train harder and longer (more "on" days with more intensity and duration on those days) and race harder and longer events that I couldn't do at a lower CTL. So one good ride in isolation doesn't really say much with regards to what your CTL is or is not doing for you in terms of your absolute performance.

I'd say keep doing what you enjoy, keep track of your numbers, and look for any trends on down the line. Then tailor your training appropriately to fit what you need.

Very interesting, making me wonder all the more exactly what fitness/freshness is actually indicating. I'm at best a high-end Cat 5. As of last month my FTP was approx. 245 as measured separately by both Kickr and on-bike power meter, putting my P/W somewhere around 2.9 to 3.0.


Below is a (lousy) snip of F/F over the last six months. F/F increased steadily from March through July, peaking in the area of 110 through July. I do think you are correct though, I probably overreached. I was feeling pretty burned out which was why I was glad for the easier workload through August.


Keith

The Science of the Performance Manager | TrainingPeaks

http://freewebs.com/velodynamics2/PerfMgr.pdf

I've been a premium user on TrainingPeaks for a few years, watch my Dashboard like a hawk and have no idea what you're talking about. Your posted image is way too tiny to have any clue about what it's showing. If my CTL hits 70-80, that's it for me. If I try to hold it there, I overreach in a couple weeks. That's the "fitness" score. My TSB ("freshness") I keep in the +20 to -30 range, with as little time as possible near 0. ATL ("fatigue") is all over the place, 30 to 120 basically because I have a life outside of cycling and enjoy doing stuff that's really hard for me and then recovering. I'm 71. YMMV.

So yeah, I find the numbers extremely useful. If my TSB is +10 or better, I'm going to have a good event. If I try to hold my TSB at -20 for very long, I'm going to overcook it.

What your ideal fitness/freshness/acute training load/chronic training load is depends on a number of factors. If you're preparing for long events, you may benefit from a high fitness/chronic training load. For shorter events, a lower fitness/chronic training load may be sufficient and be of benefit because it may allow you to train more intensely which can result in faster training improvements.

Generally speaking a fitness/CTL of 100 is considered pretty high. Maybe ideal for someone who is doing stage races or long events. Also, generally speaking, younger people and men recover better and can carry higher training loads. Older people & women generally need more rest and lower fitness/CTLs. But there is tremendous variation. Some people thrive on volume, some people thrive on intensity. Some people can be successful with either, depending on the nature of their events. This is stuff you discover about yourself with training. Higher training loads carry higher risk of overtraining. Training loads that are too low run the risk of low performance.

As an example, I am a 50 yr old woman who trains with power & has an excellent coach. Ie everything is about as optimized as possible. Last year, I raced a series of long climbing Fondo-like events- all from 100-125 miles with 10-13k ft of climbing. My fitness/CTL for the 9 months I spent prepping for those events was 90-100- pretty high for someone my age & gender but it went well & I was watched pretty closely. Now I am racing 20-40k TTs and my fitness/CTL is usually around 70. Same person, good results in my races with both high & medium CTLs, each appropriate to the duration of my events.

Most people are going to race best at a freshness/acute training low that is around zero, let's say from -5 to 15 or so. With some variation from person to person. For me, I probably race best with a freshness from 0-5. You always need to balance how fresh you get for a race with the need to not get beyond-fresh to stale. And you don't want to back off on your training so much for a race that you don't continue to prepare optimally for the next one in the pipeline.

Bottom line is that many people think more volume is best. Sometimes volume just makes you tired and takes away from your ability to train intensely enough to make real progress. 114 is probably high for a cat 5 guy, especially if you're racing crits more than road races. Not inevitably high though, just probably too high.

Yes, the image you provided is mostly illegible, however you're misinterpreting the Fitness/Freshness score slightly.

Fitness and Freshness are two different measures, sometimes referred to as CTL (Chronic Training Load) and TSB (Training Stress Balance). CTL, or Fitness, is a measure of your base training. A CTL (or Strava Fitness) score of 115 means you are averaging a TSS (Training Stress Score) of 115 every day. That's quite high for most people and difficult to sustain unless you aren't working. I can see in your graph that your TSB (or Stava Freshness) is negative while you're ramping your CTL. Once you started tapering and lowering your CTL your TSB (Freshness) rises and goes into positive territory. This is what everyone wants to do before a race and, as you observed, your performance is higher when you are fresher.

I believe Strava let's you select whether you feed Power and/or HR data into the Fitness/Freshness calculations. If you select power only I think the Strava Fitness/Freshness is the same as Dr Andrew Coggan's CTL/TSB/TSS data.

It's similar, but not exactly the same. Strava uses a different formula for Weights Power (Normalized Power in Training Peaks terminology). Above-threshold efforts are more heavily weighted in the TrainingPeaks/Coggan formula than in the Strava formula. Since normalized power is used to calculate TSS and all the other metrics, that means the Strava numbers will be a little different, especially if you're doing lots of high-intensity stuff.

The other big limitation with Strava is historical data. In Strava everything is based on your current FTP setting. So if your FTP is changing, the historical data becomes inaccurate.

That's true for the weighted average power Strava reports but my recollection was the Fitness number matched my CTL number from Golden Cheetah within a few points. Whatever formula they used also worked pretty well with just HR. I didn't notice much difference when selecting power vs HR on Strava's numbers.

I don't use Golden Cheetah, but I seem to recall somebody mentioning that it uses the same formula for NP as Strava, which if true would explain why you didn't see a difference. In fact I wouldn't be surprised if Strava got their calculations from Golden Cheetah since it's open-source.

I use a browser extension for chrome called Stravistix, one of the extra data fields it adds to a strava workout is "A. Coggan Normalized Power", which I've found is always higher than Strava's weighted power.

It's not a huge difference for most workouts, and as long as you know what your fitness/freshness numbers mean for you, it's probably not a big deal at all. I only pointed it out because even the Coggan/TrainingPeaks formula is more heavily weighted towards duration than intensity than it should be IMHO. A 120 TSS VO2Max interval workout definitely takes more of a toll on me than 120 TSS from riding zone 2, and the former takes longer to recover from as well.

Yes, I see they're not identical. The last few rides have the following TSS data: 164/169, 132/137, 199/205 for Strava/Golden Cheetah. Golden Cheetah uses Coggan's formulas for NP, TSS etc.

Basic trends are the same and Training Stress Balance is the same so I don't worry about the minor differences.

Neither formula is perfect but they're still useful to me. I can jack up my NP by just sprinting for 10-20 seconds every 5 min or so. I don't find these types of workouts particularly fatiguing but they can result in a high NP. Achieving the same NP with VO2Max intervals is more tiring for me.

Yes and no.

From what I have read strava's weighted average works the same as NP; with one exception. Strava uses a 25s rolling average before subjecting to to quartic power/root, whereas TrainingPeaks/NP uses a 30s rolling average.

Obviously, if we used a 1s rolling average, then AP = NP would always be the case. The larger the rolling average, the more higher watts get stressed.

In other words, if you had an FTP of 300 and rode for 15' at 330w and that was your entire ride NP and WAP would be identical. Strictly speaking it's not that efforts higher than threshold are more heavily weighted (because a riders threshold will not effect the NP of the ride), it's that all efforts are more heavily weighted under NP, whether they are 200w, 600w, or 1200w, but because of the effect of raising data to the 4th power, summing it, and then taking the quartic root, the higher wattage efforts are more punished the smaller the window for rolling average is.