Hello,
I am new to the site and I run and bike purely for fitness and recreation. Im very impressed with the detailed analysis of all my workouts and a clear direction on the training (or lack of!). The two things im particularly new to are the fitness/fatigue/form graphs which shows in one glance the status of my training cycle and the type of training (pyramidal/polarized etc).
I have a question regarding the factors influencing the fitness/fatigue/form graph. While the sufferfest workouts as per my plan seem to be adequately causing fatigue and getting the fitness to inch up while keeping the form in the optimal zone, the running workouts don’t seem to be getting as much response. The running workouts are using a stryd power meter while cycling are on the wahoo kickr and exclusively indoor. Cycling FTP is as per the Sufferfest app while running FTP is the Stryd CP. LTHR is per Sufferfest while threshold pace is a best guess.
Im running again after a break due to the lockdowns and hence running workouts are shorter than cycling workouts (cycling around 1 hour vs running around 30-50 mins). In terms of RPE they are more or less on par. However each running workout does not seem to induce the “desired fatigue” and the form seems to creep up to the gray zone.
Hence id like to know what factors influence fatigue, fitness and form. Is it load, intensity, duration, % of FTP or % of LTHR or some combination of these? How are load and intensity calculated? If this is already described somewhere, could someone point me to a link?
Fatigue is your 6-week moving average load per day. The average is exponentially weighted, meaning that the 5 week ago rides count less than the ones this week.
Fitness is your 7-day moving average load per day. The average is exponentially weighted.
Form is either Fatigue - Fitness or 100*[Fatigue - Fitness]/Fatigue. Which measure is on your fitness page is something you choose in options.
So, load.
Load = TSS = 100 * h * IF^2 … {^2 means squared},
where h = duration in hours of the effort
IF = intensity factor = NP / FTP
NP = normalised power.
In other words, the answer to your question is that fatigue, fitness and form are calculated from load, which in turn is calculated from duration and average [normalised] power as a proportion of FTP.
Need to run a bit longer and possibly little harder to push the fatigue and hence fitness higher. This will happen as I do all workouts more consistently.
The running load for runs with power is currently calculated in exactly the same way as cycling i.e. TSS which is relative to your FTP for the sport. It is quite possible that this underestimates the cost of running. Maybe @John_Peters_endura.f has an idea?
I also run with a Stryd. From experience my low intensity running sessions of 30-35 mins give a load of ~35-40 whereas a LIT 60min ride gives a load of 44-50, even though %HRR and %CP is higher for the run than the ride, ie when running I’m working a little bit harder but for a shorter period of time. It looks like you’re seeing something similar. I don’t necessarily think running load is under measuring, I think that running and riding are just different.
To be honest I try not to get hung up on the fitness and fatigue values, although interesting to look at after the fact they fall out of the overall resuming process. You really need to focus on the purpose of every session, don’t push a LIT run just to try and improve you fitness curve. You hit the nail on the head with being more consistent. Over time think about extending first and then intensifying. For LIT sessions try and run/ride further but at the same % power without HR starting to creep up. For higher intensity sessions can you do one more rep at the same power/effort again without pushing HR above where it should be for that session. Again consistency is the key. Over time the intensity will come as you get fitter as your CP goes up so you have to increase power to maintain the same % CP. The advantage of running with a Stryd is that you can apply the same approach to running and riding, but pace works just as well otherwise.
The most important metrics though is feel (RPE). Did the session fell right? So you need to consider the three elements in every session. internal (HR), external (Power) and feel (RPE).
Not sure if that answers your question but anyway that’s my theory in it all!!
This is exactly what I observed and hence the question on how these variables are calculated. Now that I understand the calculation a little bit, I guess duration explains a part of it and, as you say, inherent difference in these activities.
Thanks for providing a perspective on what to do with all this information. While i’m not hung up on the fitness/fatigue/form graph, I did wonder if the running plan was too easy and should be amped a bit. I think this is mainly because I have been more used to banging out tempo runs and not doing anything else. This became obvious when I saw my last few years running as classified as “Threshold or HIIT”.
Ive just started with a Stryd plan and it has me doing a fair amount of easy sessions with a good measure of running at different power zones in the middle. I will take your advice and focus on objective of each session. Im sure as the plan progresses the CP will get better, duration longer and intensity will also feel adequately challenging.
These data insights are quite helpful in understanding and planning a more structured approach to training, even for a middle aged, recreational runner (jogger?) /cyclist like me.