The whole idea behind training for muscular strength is to be able to lift heavy loads with proper movement mechanics. In this training phase, your long-term goal is to lift incrementally heavier within given amounts of time so that you can eventually reach your preferred one-rep max. In order to do this with proper technique, your muscles must be fresh and fully recovered so that they can all fire at maximum potential during time under tension. Thus, a rep range of 2-6 is recommended so that you do not lift heavy weight under fatigue. Also, a rest period of 3-4 minutes is recommended between sets to allow for sufficient muscle and nervous system recovery.
Brandon Santo is a Personal Trainer at Body & Soul