Fitness and Muscle

The simple answer here is that it all depends on what your goal is. A rep is the movement of a weight through a motion and back again once and is short for repetition. For example, if you were doing a bench press you might perform 10 reps in each set, so you would bring the bar to your chest and back up again 10 times.

With different goals the number of reps you do should also vary. For example a soccer player would be more concerned with endurance rather than muscle growth, as this may slow him down. For a rugby player however, strength and size are key.

Strength

If you’re looking for power without bulking up then 3 sets of 3 reps is the way to go. However you should be lifting about 90% of your single rep max. Your single rep max is the maximum amount of weight you can lift in one repetition.

Lean Endurance

If you want to strip fat and have more definition then its better to do more reps with lighter weights. 3 sets of 15 reps lifting around 60-65% of your single rep max should do this. This will give your muscles an anaerobic workout, and help to tone the muscles instead of bulking.

Maximum Muscle Growth

If its bigger muscles you’re looking for then do 3 sets of 12 reps at around 80% of your single rep max. This will tear the muscle fibers allowing them to rebuild and grow. Just make sure you get plenty of protein after your workouts to help the rebuilding process of the muscle, and plenty of rest between workouts. 48 hours is usually advisable.