The 1.5 method is simple: Perform full reps of an exercise with partial reps between each. Although 1.5 means "one-and-a-half," quarter reps can also be used.

One benefit: 1.5s increase TUT (time under tension) in the portion of an exercise that emphasizes a certain muscle.

Decide what your target muscle is, then determine what portion of the exercise loads the muscle the most. For example, booty-builders might want to squat deep to get more hip flexion and glute loading. So do an extra partial rep at the bottom to, well, hit your bottom. (See what I did there?)

To hit your pecs more in a barbell bench press, do an extra touch-and-go off your chest to really fire up those pecs. The top portion of a squat will emphasize quads more, so spend more time at the top with a partial rep. Squat example shown in video. – Gareth Sapstead