Calculate Needed Training Load?

Training
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I’m coming back to this topic 3 years later and I’m still wishing that Intervals would just tell me what load range I need for today to stay within -10 to -30.

I did the math on the spreadsheet that I created way back when and somehow I got it very wrong - I thought I needed to do a load of 70 to move from -9 to -10. Load 70 moved me to -17 and now I’m too fatigued (and don’t have the room) to do a century I had planned for tomorrow.

I’m back to training for this 160 mile ride in July and it just takes A LOT for a normal, non athlete person to get there.

It would just be really helpful to have on the calendar and the fitness chart to do the math of what training load I need just for today to maintain a form of -10 to -30.

Off topic I’m also sort of curious how long you can effectively remain in Optimal Training form - seems like at some point it would have mixed results.

2 Likes
71

Hi Jason,

I feel like I’ve posted this before, but maybe not on this thread.

I’m using the usual exponential decay formulae with the normal 42 and 7 day figures, which gives me that new Load contributes 0.023528*Load to Fitness and 0.133122*Load to Fatigue and Fitness decays to 0.976472*Fitness and Fatigue decays to 0.866878*Fatigue overnight.

If you’re going to do some LOAD today, and you want to know how much to do to keep yourself at Form = -10:

Fitness(new) = Fitness(old) + LOAD*0.023528
Fatigue(new)= Fatigue(old) + LOAD*0.133122

You want Fitness(new) - Fatigue(new) = -10. So, substituting:
Fitness(old) + LOAD*0.023528 - Fatigue(old) - LOAD*0.133122 = -10

Rearranging, you get:
LOAD = (10 + Fitness(old) - Fatigue(old))/(0.133122 - 0.023528), or

LOAD = (10 + Fitness(old) - Fatigue(old))/0.109594 [Formula 1]

Similarly, for Form = -30, the formula is:

LOAD = (30 + Fitness(old) - Fatigue(old))/0.109594 [Formula 2]

You didn’t ask for this but, if you’ve finished for the day but you’re going to do some LOAD tomorrow, you need to take account of the decay overnight:

Fitness(new) = Fitness(old)*0.976472 + LOAD*0.023528
Fatigue(new) = Fatigue(old)*0.866878 + LOAD*0.133122

You want Fitness(new) - Fatigue(new) = -10. So, substituting:
Fitness(old)*0.976472 + LOAD*0.023528 - Fatigue(old)*0.866878 - LOAD*0.133122 = -10
Rearranging, you get:
LOAD = (10 + Fitness(old)*0.976472 - Fatigue(old)*0.866878)/(0.133122 - 0.023528), or

LOAD = (10 + Fitness(old)*0.976472 - Fatigue(old)*0.866878)/0.109594 [Formula 3]

Similarly, for Form of -30, the formula is:

LOAD = (30 + Fitness(old)*0.976472 - Fatigue(old)*0.866878)/0.109594 [Formula 4]

So these four formulae are what you need (apart from stopping them going negative).

So, for example, if you look at your current Fitness and Fatigue values, plug them into Formula 3 and plan an activity for tomorrow with the Load it proposes, you should see your form curve hitting -10. It might not be spot-on because intervals only displays rounded figures for Fitness and Fatigue.

You really want intervals to display these for you, and custom activity fields might let you do it, but you really have to have done an activity - you can’t display them at the Fitness level (at the moment).

Hope that helps.

1 Like
72

Appreciate this

  1. I want the app to do this math

  2. the copy of load training example file which I thought was based on this no longer calcs accurate values

73

  1. It’s just not possible at the moment, I believe. For now, you might have to create a little spreadsheet of your own where you plug in your current Fitness and Fatigue values (read from intervals) and get it to calculate the four Loads (Today -10, Today -30, Tomorrow -10 and Tomorrow -30).

  2. I’m not sure what’s going on there.

74

Two things I find myself doing on a daily basis :

  1. Plugging in fake rides to see how much Load I need to get back to -10 for the day
  2. looking up how many miles (+ elevation), how long and what my average power was for my last 5 rides that were +/- 5 the target load

I would think the app could do this.

1 Like
75

Sorry @David and not that you don’t already know this - this is what Xert does. Or at least in my opinion, tries to do.

I’m a former Xert user. I feel like it consistently over-estimated my FTP, and the recommended workouts always seemed like too much work. This made hard workouts too hard, but even for “easy” workouts Xert recommend a lot of high Z2 work that was closer to its estimated LT1, and IMO this is still too hard even if it has the correct FTP.

It also often recommended what I felt were overly complicated workouts. I don’t like doing hours of different zone 2 intervals. This was mentally taxing for me. Riding for 3+ hours at one target power is just fine for me. And I don’t need the mental load of looking through a bunch of potential workouts to find one that meets my overly sensitive needs. I can write one in intervals in like 30 seconds (I’ll mention again that once you figure out the workout builder here it’s the best there is!)

I think Xert is also just overcomplicated in general. The adaptive workouts? Always seemed to make it easier when I was feeling good, and harder when I was feeling crap. While there is an argument that the former may actually be better (you can read my other thread on that!), there’s no argument that the latter is good!

I’m also pretty sure there are companion apps for intervals.icu that can do this. I’d check that out in settings for other tools that can work with intervals.icu and try those out before making a wholesale jump to Xert or another tool. Gives you a chance to find one that recommends workouts that match what you like.

My issue with these “AI” training platforms is that it’s just crunching the numbers and spitting out whatever its algorithms say. You can tweak it by saying you are tired or you are fresh. But now I’m trying to tweak how a black box is telling me how to tweak my training.

Ugh. As my friend said, “Do you believe the number, or do you believe what your legs are telling you?”

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yah the legs vs numbers thing I covered in another thread.

I just want to hear what the numbers say and I think my request is relatively straightforward.

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Take it to Feature Requests. I suspect that for the very specific thing you are asking for, it could be relatively straightforward. I’m not sure how valuable that very specific thing is going to be, but that’s the place to explore your question, not as part of this thread.