# Rm Formula?

Discussion in 'General Training' started by NWlifter, Nov 4, 2018.

1. ### NWlifterActive Member

Hey, is there some equation or something to calculate RM's, most charts only go up to 12RM.
I'm wondering, if you knew any RM, if there was some way to calculate all the way up to 20RM.

3. ### SciWell-Known Member

I would say do your own experiments. Jot down your 1, 5 and 10 rep Max numbers, then see how many reps you can do of progressively lighter weights. Since you are doing all out max effort sets, I would only do one experiment set per session.

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4. ### NWlifterActive Member

that would work.. of course, I was going for the math instead of the 3 weeks of testing LOL.

5. ### _Simon_Active Member

Hey, I fished through my books and found this. I don't think it's too old a book... 2007ish?

It's some equations to figure out your 1RM, but surely if you know your 1RM you can reverse engineer it to figure out your 20RM maybe.. ?

But the Mayhew, Ball, and Bowen, 1992 one was designed specifically for the bench press exercise apparently, so not to be applied to others (who knew!).

Also included the prediction table in the book (only goes up to 15RM though), sorry for the horrible photos, let me know if you need better quality!

6. ### JesterWell-Known Member

I imagine you can test 10, 15 and 20 RMs in the same session if you have some glucose as you go and don’t mind being a rep or two off.

Can’t figure out when precision for 20RM will matter enough, and a formula won’t account for the CV contribution.

7. ### NWlifterActive Member

Simon,cool thanks, I will see if I can figure out how to do that, thanks for taking the time to post all that!

Jester - It's 1/2 cause I wanna figure it and 1/2 cause I wanna just know how to figure it There has to be a formula they use, curious on that.

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8. ### _Simon_Active Member

I've always wondered about RM calculations though... I've seen some people's figures, and other people who have a similar 12RM to me have had wildly different 5RMs to me, so I have a feeling it's more to do with individual body types, limb lengths and leverage, muscle fibre composition etc.. but I could be wrong!

AND it just came to me also energy systems and how they come into play... if someone has shocking stamina/energy production doing higher reps like 20RM and up, but is super strong in 5RM and lower, then predictions can't really be made across the board for all people hey... interesting...

9. ### NWlifterActive Member

Yes all true! Good points!

10. ### JesterWell-Known Member

I think either/each can be trained for, and improved upon. It’s certainly less likely a natural lifter will excel at both, simultaneously, for extended periods. However performance =/= future potential performance, in the context where one is focusing on 5RM instead of 20RM etc.

It’s also worth noting that improving a heavier RM will drag that lighter RM upwards, kicking and screaming perhaps, but it absolutely will.

11. ### _Simon_Active Member

Ah yep, well said. I guess I mean that they're very different energy systems and so on at the different RM ranges. So someone who has a really great endurance capacity may have a 5RM of 100kg and a 20RM of 50kg, and someone who doesn't have that great endurance can have exact the same 5RM, but much lower 20RM.

So not sure how accurate the calculations and tables can be... Perhaps when translating RMs that are much closer to each other it might make sense... these are just ponderings btw haha

12. ### JesterWell-Known Member

I think the most important thing to bear in mind is the current training environment and direction - are they training for 5RM or 20RM when you’re testing them?

The demands of each are vastly different.

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13. ### NWlifterActive Member

Good points everyone, OK I won't worry about estimating, thanks!

14. ### JesterWell-Known Member

It would interesting to train both once a week (DUP), for say 3-4 weeks, and see what happened.

I wouldn’t do it for dead’s, squats or anything else full body. But bench, OHP, rows, pull-ups or pull downs would all be interesting.

No point for curls really, your 5RM and 8RM and 10RM would be too close together I would think.