One of my favorite Sets combines stroke techniques and breath holding.
I do 10 x 50s, holding my breath so that I take onle 2 breaths for the whole 50. What I have found is that my freestyle stroke technique improves because you are forced to use the most efficient stroke possible to accomplish this. If you go to fast you burn your O2 to fast; go to slow and O2 runs out. You force your stroke to be smooth and efficient, which is always a good technique.
I do mine on 1 min intervals, though time is not as important as completing the swim smooth and efficiently
I count my strokes and breath on the first lap after 7 strokes, do the turn, take a breath and go 13 strokes to the wall without a breath. I take my first breath way ahead of the turn so that I have air and a good rhythm going into the turn. As my effiency improves I plan on droping the first breath and only breath after the turn.
Try it, its feels great.
