Weight v reps
Less weight more reps or more weight less reps? Which one adds muscle faster
If you want to bulk then high weight low reps (about 5 reps no more than 8). If tone and definition is what you want then low weight high reps is better (at least 12).
Its a bit of both really.
In order for your myscles to grow you need to put them under tension. Thats the weighttraining part.
Hypertrophy (muscle growth) is at its best at sets arround 12 reps. This makes for for the best time under tension to trigger growth. But at the same time you want to grow stronger to be able to use higher weights and put your muscles under bigger tension. The strenght reflex of the body gets triggered when using highest weights you can use on lower reps 1-5.
For pure bodybuilding purposes. The usual bodybuilding routine of 3 sets of arround 12reps has proven to be the most effective. Looking at it from a more strenghttraining view it should be a balanced mix.