Whats better for sprint training out of...?

Question

running up stairs fast one at a time or running up fast two at a time?

Answer 1

One at a time as fast as you can, and work on your form

Answer 2

You can alternate routines.

As long as  your form is good and your legs are moving correctly.

When doing stairs it is good to run touching each step, then next time touch every other step.

You can hop up the stairs using the same methods.

Answer 3

The more steps the better, as long as you also increase your arm movements. It's basically a slimmed down version of power skips.