Effective repetitions

Hello. I have some confusion regarding effective repetitions. I understand that a load of 80% of 1RM already recruits all available fibers, so all repetitions should be considered effective. However, I have read opinions that state that only the last 5 repetitions of a series to failure can be considered effective, that is, in a series to failure with 80% of the 1 RM we would have 5 effective repetitions and approximately 3 ineffective ones.
I have recently started implementing these concepts into my routines and would like to have things clearer.

Thank you.

There’s no answer. Maybe too obvious, except to me.
Lately I’m considering ladder series. I wonder about the effectiveness that doing sets 1-2-3/1-2-3/1-2-3 with an 8 RM (80% RM) could have for strength and/or hypertrophy compared to a 5 RM (87 %RM).
By using 80% we will always be far from muscle failure. That’s where my question comes from if all repetitions could be considered effective or would it be necessary to use 87% RM.
If it is true that with 80% all the available fibers are activated, what sense would it make to make the stairs with, say, 87%. I understand that with the higher load, having a higher encoding rate, it would be even more favorable for developing strength. Maybe if I had to do it I would choose this second option…if necessary.

I have read some of your articles in which you analyze some training systems such as 10x10 or 5x5. Everything I have read has seemed interesting to me. I especially like that you put numbers to things.
I have dared to do my own analysis of the relative variation of the load repetition by repetition and for that I have based myself on two premises:

  1. That each repetition subtracts 3% of strength
  2. That breaks allow you to recover 2%

Using 80% RM:
1st repetition: 80% (-3%)
Pause (+2%)
1st repetition: 81% (-3%)
2nd repetition: 84% (-3%)
Pause (+2%)
1st repetition: 85% (-3%)
2nd repetition: 88% (-3%)
3rd repetition: 91% (-3%)
Pause (+2%)
1st repetition: 89%
2nd repetition: 92%
3rd repetition: 95%

Using 87% RM:
1st repetition: 87% (-3%)
Pause (+2%)
1st repetition: 88% (-3%)
2nd repetition: 91% (-3%)
Pause (+2%)
1st repetition: 92% (-3%)
2nd repetition: 95% (-3%)
3rd repetition: 98% (-3%)
Pause (+2%)
1st repetition: 96% (-3%)
2nd repetition: 99% (-3%)
3rd repetition: 102% (-3%)

The only thing I am clear about is that to get all the repetitions the pauses should be longer in the second example.
I would like you to give me your opinion on this.

Greetings.

(translated with Google)

Try one set to failure. 5 second positive and a 5 second negative each rep. Once you hit failure continue to push or pull for 10 more seconds. Measure by time uder load. Once you reach 90 seconds TUL on a lift increase your weight by 5% the next time you do that exercise.