Originally Posted by KenN
How does one determine the optimal number of repetitions to perform for a particular exercise? Do different muscle groups respond better to different loading and stresses?
According to some sources, the optimal range for reps in a set for maximal hypertrophy would be 5-8. Myself, I tend to mix it up depending if its a heavy/light day - I'll normally do warm-ups w/ either 10 or 8 reps and working sets of 5-6 a piece. Less reps in a set allows you to use heavier poundage, which may or may not be to your liking.
Sorry if this didn't really answer your question that well.