Have not read david's original post yet...David I'd suggest you post an excerpt here on your TI blog as well...it will then go out with teh next TI newsletter...and can bring more traffic to your site.
But I like the ensuing discussion.
I have a some former collegiate swimmers that come to my masters practice. I have to be certain I am giving them tasks they enjoy that also beneits their swim. One day I gave a triplet of descents. 3 rounds, 3 repeats each, descend each round. I let THEM choose the range of efforts...so if they wanted to keep it easy they could, if they wanted to sprint the final repeat of each they could. Repeats started at 100yd and ended at 300yd. So it looked like this:
3 x 100
3 x 200
3 x 300
Within each 3x, the repeats got faster. The only requirement for the ex-collegiate swimmers was that they choose a tempo & SPL combination they felt comfortablew ith that would result in the faster time. Both of them have rock solid SPLs for 25yd for any given effort, as charles is describing. So I had them simply descend their tempo trainer by .02 to .03 each repeat.
The results were eye opening. I mean predictable...but they felt something different in their stroke that they never really felt before. While Mir's SPL stayed at 9 the entire set, as she descneded the TT she dropped 3 seconds per 100 precisely the whole way through.
What she felt was where she applied pressure in the stroke was different. at each tempo. and while she could execute that prior, she had never thought about it prior, or really drawn any awareness to that effect.
So there are many ways to coach a set like that, 3 rounds of 3x descending repeats (of any length). A TI approach is about more than just the stroke, it's about being mindful of how you create that speed. And for every swimmer, it will be a different solution. There is something for everyone in it.