Ladies, if you are wanting to gain muscle and improve your shape and curves, then you are going to have to lift some heavy weights. The time of lifting light weight for 200 reps is OVER! Yes! You are free of that 5lb dumbbell. Guess what, if it doesn't challenge you, it doesn't change you! Go ahead and increase the weight! I'm not saying that performing high reps (15-20 rep range) is not beneficial, because it is, BUT it is not the best way to gain muscle MASS. Below is a GENERALIZED REP RANGE equaling how MY body responds. Sure, yours may indeed respond to the ranges differently. This is just a guideline.
1-5 reps = Strength (choose a weight you can lift for 1 rep but not more than 5 reps)
6.12 = Hypertrophy (choose a weight that you can lift for at least 6 reps but not more than 12 reps)
12+ = Endurance