YOU WILL NOT "BULK UP" IF YOU LIFT HEAVY WEIGHTS.
YOU WILL NOT BECOME "TONED" IF YOU JUST LIFT LIGHT WEIGHTS.
Although I've heard this statement from both men and women, the majority of the time it comes from women. Because of this, I'm going to direct this post to women in particular...
The female sex has approx. 1/10 of the testosterone men have. Testosterone is a hormone that contributes to muscle mass gain, therefore making it difficult for women to gain muscle mass.
Lifting heavy weights is actually a GOOD thing, especially for women. It provides an increase in strength and metabolism, and a decreased risk of developing osteoporosis (bone loss).
Lifting light weights on the other hand, is not a good thing. Read this article to find out why.
If you're one of the people who walk into the gym, grab 2.5 lb dumbbells, and proceed to do 500 curls, please (please!) stop. You're wasting your time. Don't be afraid to lift heavy. And by heavy I mean choosing a weight that will challenge you for the desired amount of repetitions!
And stop using the word "toned." There is no such thing.
That is all. Thanks for reading my rant.
Make it happen.