How do you run faster? Do you use weight?

Answer 1

A lot of your speed comes from explosive off the line power. The quicker you get going the faster your times. Ankle weights can help you in this but quickness training is the best way to go.
Training for quickness is not the same as training for absolute speed. Quickness relies heavily on immediate movement reactions. Think of quickness as the first phase of speed.
try this web site for more answers to your questions on both sustained speed and quickness training.
http://www.bodybuilding.com/fun/hale12.htm