question about '~4-5 RIR for hypertrophy'

[RWulys]

Hi BBM,

My question is essentially this post’s ‘title’ + ‘why?’

I had previously believed that, all else equal, all reps over ~70% 1RM are about equally effective in terms of hypertrophy (regardless of rep schemes and proximity to failure). After looking at a recent thread here on the forum, it seems that they are about equally effective only for strength development. (I’m sure I’ve missed something here, since of course hypertrophy is a factor in strength development).

My belief was based on the notion that all reps at ~70% 1RM or higher cause more or less equal motor unit recruitment, from pretty much the first rep in the set onward. Perhaps that part is true, but from what I’ve recently read it still seems as if ~4-5 RIR is best for hypertrophy.

My question is, again, why that is.

I had originally intended to ask “if all reps at ~70% 1RM and over, are equal wrt hypertrophy, then why necessarily do ~4-5 RIR on sets (since I had seen you give this recommendation before)? I get that we don’t want to go to failure, let’s say 4x15 at RPE10, as the fatigue cost would be very high, and should instead just do more sets to hit that same volume, 6x10. So why not, along that same line, instead do e.g. 12x5, or 30x2, or even 60x1?”

With that said, I suppose I could also ask whether 12x5, 30x2, or 60x1, would be equally good for strength development as 6x10?​- along with the original question of why ~4-5 RIR for hypertrophy; why is that better than say 10 RIR, assuming that total volume and everything else is equal?

All I can come up with is that maybe not every but only almost every rep of a set is effective (like from the 3rd rep onward) and therefore we get more effective reps with 6x10 than say 12x5 afterall.

[Jordan_Feigenbaum]

@RWulys

since of course hypertrophy is a factor in strength development).

Is it? I’m not so sure I would universally agree.

@RWulys

My belief was based on the notion that all reps at ~70% 1RM or higher cause more or less equal motor unit recruitment, from pretty much the first rep in the set onward. Perhaps that part is true, but from what I’ve recently read it still seems as if ~4-5 RIR is best for hypertrophy.

It’s not that it’s best, it’s just likely equivalent to going to failure, but without the cost of doing so.

@RWulys

My question is, again, why that is.

It’s driving the same processes for muscle protein synthesis increases in the same magnitude as training to failure.

@RWulys

I had originally intended to ask “if all reps at ~70% 1RM and over, are equal wrt hypertrophy, then why necessarily do ~4-5 RIR on sets (since I had seen you give this recommendation before)? I get that we don’t want to go to failure, let’s say 4x15 at RPE10, as the fatigue cost would be very high, and should instead just do more sets to hit that same volume, 6x10. So why not, along that same line, instead do e.g. 12x5, or 30x2, or even 60x1?”

~30% 1RM seems to give the same hypertrophy results as heavier sets, provided we get somewhere near failure.

@RWulys

With that said, I suppose I could also ask whether 12x5, 30x2, or 60x1, would be equally good for strength development as 6x10?​-

​

Maximal strength, e.g. 1RM’s? No, because strength is specific to how it is developed.

I think the sooner we stop thinking about training as binary “effective reps” vs “non effective reps”, the better.

You may also enjoy the ebooks included with the low fatigue and bodybuilding templates for further explanation.

[RWulys]

Thank you, Jordan.

Is it? I’m not so sure I would universally agree.

Then I’ve gotten things wrong. I thought that when all else is equal (like neurological adaptations), hypertrophy is the main driver of strength development; iow, all else being equal, bigger muscles means more strength.

Alright. So, sets at ~30% of 1RM and over give the same hypertrophy results, provided we go near failure (~4-5 RIR). This seems straightforward, but to be clear, you’re saying that e.g. a 5 RIR set of 30 gives the same hypertrophy results as a 5 RIR set of 10? Or are you saying that each rep in the 30 rep set gives the same results as a rep in the 10 rep set? Because, it can’t be that a 5 RIR set of 1 rep gives the same hypertrophy results as a 5 RIR set of 12 reps, can it? I’m guessing the latter interpretation is correct, or else total volume would be irrelevant for hypertrophy, which, afaik, it isn’t.

The other thing I don’t yet understand is, why sets with ~4-5 RIR for hypertrophy. Why is it better for hypertrophy to do sets of 30 with 5 RIR, than sets of 20 with 15 RIR (assuming equal total volume), especially when the “effective rep” concept isn’t really accurate?

[RWulys]

In case my question wasn’t clear:

My understanding thus far is that sets of ~30% 1RM and over are equal wrt hypertrophy results, provided that proximity to failure AND total volume are equal.

So e.g., doing sets of 15 reps, with 5 RIR, is equal in terms of hypertrophy results to doing sets of 25 reps, or of 10 reps, with 5 RIR, assuming that total volume is equal.

And, a set of 10 with 0 RIR, would be equal in terms of hypertrophy to a set of 10 with 5 RIR.

What I’m wondering is why a set of 10 with 10 RIR wouldn’t be. That’s a 20RM weight, which is well over 30% 1RM, so it isn’t about the intensity. Nor is it about the volume, as it’s the same volume as above. What happens in the body when doing sets with ~4-5 RIR or less that yields better hypertrophy results than would doing sets with for example 10 RIR, since it’s not about the intensity nor the volume? I used to think it had to do with “effective reps”, but since that isn’t case, what is?

[Jordan_Feigenbaum]

@RWulys

Then I’ve gotten things wrong. I thought that when all else is equal (like neurological adaptations), hypertrophy is the main driver of strength development; iow, all else being equal, bigger muscles means more strength.

The first part, “I thought that when all is equal…” is not equivalent to the second part “…bigger muscles means more strength.” In cross sectional analyses, yes, those with the biggest muscles tend to be the strongest. Yes, when people get stronger, many times (but not always) they will see an increase in muscle size. Getting bigger muscles in and of itself doesn’t necessarily increase strength and we don’t know that modest changes in muscle size play a causal role in increased strength performance.

@RWulys

Alright. So, sets at ~30% of 1RM and over give the same hypertrophy results, provided we go near failure (~4-5 RIR). This seems straightforward, but to be clear, you’re saying that e.g. a 5 RIR set of 30 gives the same hypertrophy results as a 5 RIR set of 10?

Pretty much.

@RWulys

Or are you saying that each rep in the 30 rep set gives the same results as a rep in the 10 rep set? Because, it can’t be that a 5 RIR set of 10 reps gives the same hypertrophy results as a 5 RIR set of 12 reps, can it?

Why can’t it be? Yes, total volume matters- so perhaps we shouldn’t ask questions about a single set.

@RWulys

The other thing I don’t yet understand is, why sets with ~4-5 RIR for hypertrophy. Why is it better for hypertrophy to do sets of 30 with 5 RIR, than sets of 20 with 15 RIR (assuming equal total volume), especially when the “effective rep” concept isn’t really accurate?

Doesn’t seem to drive enough total mechanical tension, metabolic fatigue products, and what not to drive the hypertrophy process optimally. Some people will still get stronger and gain more muscle by doing sets of 20 @ 15 RIR though. Again, it is unlikely that questions about single sets in the context of an entire program will not teach you how to program or understand programming principles. I think the ebook included in the Low Fatigue and bodybuilding templates would be useful.

@RWulys

​
What I’m wondering is why a set of 10 with 10 RIR wouldn’t be. That’s a 20RM weight, which is well over 30% 1RM, so it isn’t about the intensity. Nor is it about the volume, as it’s the same volume as above. What happens in the body when doing sets with ~4-5 RIR or less that yields better hypertrophy results than would doing sets with for example 10 RIR, since it’s not about the intensity nor the volume? I used to think it had to do with “effective reps”, but since that isn’t case, what is?​

See above.

[RWulys]

Thanks a lot, Jordan!

(why it’s better for hypertrophy to do sets of 30 with 35RM, than sets of 20 with 35RM, assuming equal total volume) Doesn’t seem to drive enough total mechanical tension, metabolic fatigue products, and what not to drive the hypertrophy process optimally.

But is that not an instance of the “effective reps” concept? I believed the whole idea of “effective reps” to be that the closer one gets to failure, the more “effective” (for hypertrophy) the reps become.
So, like, 4x15 with 5RIR/at 20RM vs. 6x10 with 10RIR/at 20RM – intensity and total volume are equal; what differs is proximity to failure of the sets… I thought that was precisely what “effective reps” was about. If not, then what is it about?

[Jordan_Feigenbaum]

@RWulys

Thanks a lot, Jordan!

But is that not an instance of the “effective reps” concept? I believed the whole idea of “effective reps” to be that the closer one gets to failure, the more “effective” (for hypertrophy) the reps become.
So, like, 4x15 with 5RIR/at 20RM vs. 6x10 with 10RIR/at 20RM – intensity and total volume are equal; what differs is proximity to failure of the sets… I thought that was precisely what “effective reps” was about. If not, then what is it about?

For your example, all the reps are equally as effective for hypertrophy, provided some threshold of fatigue products, tension, etc. are generated. There are likely other mechanisms we don’t know about as well.

FWIW, I don’t think there would be a difference in hypertrophy between those two products.

Most effective reps folks would not agree with 4-5 RIR being the lower bound, but rather 0-2 RIR and that the last few reps as one approaches failure are most useful.

[RWulys]

FWIW, I don’t think there would be a difference in hypertrophy between those two products.

Why not? I mean, what about 4-5 RIR being the lower bound for generating sufficient fatigue products and tension?

[Jordan_Feigenbaum]

@RWulys

Why not? I mean, what about 4-5 RIR being the lower bound for generating sufficient fatigue products and tension?

Because it’s one exercise out of context and this stuff is absolutely not black and white. I also don’t think it matters nearly as much as the amount of effort you’re expending here. In any case, if you have further questions on programming, you may enjoy the ebooks included with the low fatigue and bodybuilding templates.

[RWulys]

Alright. Thank you for the knowledge, Jordan!