Just wondering if anyone has tried using stretch cords to supplement their swim training and if so, what type of workouts did you do? I'm coming off a terrible swim at St Croix 70.3 last weekend and heading into a fresh Ironman training program in prep for IMFL. I'm sick of playing catch up from the moment the gun goes off!!! A good friend of mine (who is quite a good swimmer), says the cords drastically improve your pull. Any input?