As someone who firmly believes in a "scientific approach" to my own program I found this a good read (see below). That said, if we looked at my running program what you would find is that it hasn't changed much other then volume since the mid-90's.
I learned how to get myself into good shape, get the intensity flowing early to mid-season, keep it there and sharpen, taper and race.
That's not technically scientific because other then my benchmarks at the track, I'm not doing LT testing, not really super concerned with increasing one or the other metrics. What I *can* say is that I know very specifically what training inputs will produce Y racing outputs.
Cycling, more scientific by a long shot and the power meter has made life alot easier with regard to training myself to race properly.
I'm getting there on the swim after a couple of seasons of actual thought applied to it, sad to say the other seasons I didn't even bother thinking about the swim or even really trying to improve mechanics and workout selection.
Here you go..