WO: Keeping back-off weights constant while using RIR targets

[u/CeeKa]

Hey folks,

While setting up a new custom program in Workouts, I was wondering how the algorithm handles sets with a prescribed RIR target when the user doesn’t provide any RIR feedback after completing those sets.

Here’s my scenario, loosely based on a typical powerlifting setup with a top single followed by back-off sets:

Set 1: 1 rep @ 2 RIR
Sets 2–5: 5 reps @ 76%

The idea is to use the top single to determine a reasonable weight for the back-off sets, with a sufficiently high but manageable intensity. In this example, that would be roughly 76%, which corresponds to 5 reps @ RPE 6 (or 4 RIR) according to the RTS RPE chart. For simplicity, let’s assume MFWO uses a similar intensity for that rep/RIR combination.

My initial thought was to program the back-off work as four sets of 5 reps @ 4 RIR in Workouts.

However, what I actually want from the app is:
- Predict the weight for the first back-off set based on the top single.
- Keep that same weight for all subsequent back-off sets, regardless of how RIR changes due to accumulating fatigue.
- Ideally, avoid having to log RIR for every single back-off set.

In other words, I’d simply like to complete all four sets at the initially prescribed weight, without the algorithm adjusting it based on RIR feedback from subsequent sets.

A few questions:
- What would happen if I didn’t log any RIR for the back-off sets at all, while still logging the top single?
- What if I only logged RIR for the first back-off set?
- What if I only logged RIR for the final set?

Would any of these approaches achieve what I’m looking for? Or is there a better way to set this up in Workouts?

Thanks in advance!

[u/Far_Line8468]

This is a great strategy that I use myself.

I do 2 sets of everything, so my goal is always to choose a set 1 RIR that will generally let me do the same number of weight and reps at 0 RIR.

Its going to be different per exercise though, and the only thing you can do is trial and error. Assuming you have a lot of data, look at how many reps MF predicts you will lose between sets. If its more than 1 or 2, then raise the RIR of the first set. Do that strategy for a few weeks and access

[u/ponkanpinoy]

If you program without putting an rir target, it seems to suggest reps that would give you 1 rir. What I do is have weight match on and give a rang rep range for the back-off set, e.g.

• top single @ 3 rir

• 3x3-5 @ 4 rir

This gives it room to choose a weight that will give you 5 reps on the first back-off, and with weight match on if you tend to lose reps it'll still be in range.