this is exactly why I don't do it. I can walk at a pace that is almost faster than I can jog foever but the moment I start having both feet off the ground at once I can't breathe. I kinda have the same problem with swimming a front crawl. I just can't get the cadence right and end up inhaling water. I do believe the key may be in your breathing rythm vs your physical movements based on my own ineptness. Take that for what you will.