Short to Long/Long to Short

I was wondering exactly what those meant as I was reading a previous post with those mentioned and was still a little confused? What would be better for a 400 runner (if there is a better)? What is an example workout of each (or basic outline/principle of each)? Thanks.

With a biochemical taper you can do both…you can use vertical integration methods or Multi layer work proposed by others…

Originally posted by Clemson
With a biochemical taper you can do both…you can use vertical integration methods or Multi layer work proposed by others…

Could you maybe elaborate a little more on that? I am new to designing my own workouts and training methods, etc. so I am trying to learn as much as possible.