@kc8vji This study doesn't take into account long term muscle composition change when doing exclusively low rep high load training.
This is very important for elite athletes such as Olympic lifters, javelin throwers etc.
For them, especially if competing in weight class sports, it is important to train only type of muscle fibers that benefit them most. In time this will cause their muscle to hypertrophy one type and atrophy the other less desirable type of fibers.
For them, low rep high intensity training and avoiding anything over 5 reps is what they must do.
For anyone else, including strong man and powerlifters it doesn't matter. The benefit is in using all types of muscle fibers we have available.
As far as RR is concerned, one should progress to the next progression when able to perform at least 5 good form reps. Till then, one should work on increasing reps and even after that, we could do a mix of progressions for a while. This also depends on available progressions and the difficulty level between them.
