The number of reps might not be as important as many claim, if you are not training for competition the number of reps are not that important for anything except maybe bench. [1] This course from coursera did have some good research based content [2] [1]https://journals.physiology.org/doi/full/10.1152/japplphysio... [2]https://www.coursera.org/learn/hacking-exercise-health