Modify this sprint workout based on how long you have been building your base, injuries, and ability. If you have just started running, only do the sprints 3-4 times. If you are just beginning your speedwork, only do the sprints 6-8 times. Advanced runners can complete the 10-15 sprints.

Warm up with 1 mile easy then complete 15 X 100m all out sprints followed immediatly by 2:00 recovery jogs. After warm up sprint 100m all out effort followed immediatly by a 2:00 recovery jog. Repeat.

Cool down with 1/2 mile easy.

If you are doing this on the treadmill, make sure you keep the incline at a minimum of 1%. And only start "counting" your sprint when treadmill is up to YOUR max speed.