Being new to sprint training (as a coach), where can I find, or can someone explain training “short to long” and “long to short”
The Charlie Francis Training System e-book explains a lot (it’s available relatively cheap on this site). You can also begin by searching throughout the forum with the search button (upper right side of the screen) and browsing the topics. The Fundamentals section has a lot of beginner info as well.
Short-to-long
It means you work on acceleration first, then move to working on max velocity, then speed and special endurance. (it’s a little more complex than this, but that’s the basic idea)
Long to short
You begin at longer distances with some accel work and you slowly work into more speed work as the season progresses. It’s used more with people who aren’t that fit or with the longer sprints (400m).