Try running on a tredmill regulary.

i know ur a vollyball player but im in softball and i was pretty slow to. wat i did was i timed myself running to first base. every time i tried harder and harder to beat my time. so u could do this in ur backyard or something. the most important thing u need to do this is u need to strive to become better. hope this helped :)

set a goal for your self and try to beat it when you do keep setting higher ones till you are satisfied for your self

Try building up your leg muscles by running up stairs or doing 10 min of running every night. You'll be suprised how fast your legs will build muscle. But remember to stay hydrated!!!

Run around the park for 5 km everyday....lol that's wot I did...well not everyday. But yeah.

Start running a mile a day. This will help your endurance greatly, even for sprints. You also need to train your muscles to be able to move quickly. Two of the best ways I have found to do this are either run the 100 Meter a lot or run up and down a lot of stairs (be careful!) and move your feet as quickly as you possibly can. You also want to try and get a good long stride while you run so that you're using up less energy than the other girls. A good thing you can do on top of that is to eat right. Avoid soda and other sugary drinks and foods and that will greatly improve your energy level.