Weight, number of sets, reps and recovery time were all taken into account, although they weren't necessarily constant. You can devise a relationship between s

Weight, number of sets, reps and recovery time were all taken into account, although they weren't necessarily constant. You can devise a relationship between someone's 1 rep - 12 rep max and adjust for it, check out epleys formula https://en.wikipedia.org/wiki/One-repetition_maximum https://en.wikipedia.org/wiki/One-repetition_maximum