If you want to run fast, then run fast. Use the movement that most closely resembles the activity you are trying to enhance. Other activities, like cycling, do not have as great a transfer of training effect to running speed as running itself. In the weight-room, this means getting off the bench and getting into the squat rack. Running is primarily hip extension.
Squatting is primarily hip extension.
To get even more specific, you can try one-legged squats. The best way to do these is to get a pair of dumbells and perform them like a step-up on a bench. Lunging could also be used as a running specific weight training movement, but tends to be less explosive. To mimic the explosive hip extension of sprinting, try clean pulls from the floor. Throw in some stiff-leg deadlifts for hamstrings and your choice of abdominal work for trunk strength and stability.