Calculate Needed Training Load?

Training
70

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.

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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.