I was watching a tennis instructor train a girl, he had her do a move like a goose steps some armies use when marching. He said there were many drills for developing explosive moves. He said that running was good for endurance but drills like this would benefit her in matches. I forget the term he used. So it maid me think about my training. I can run at 5.0 for about an hour with no problem and also 6.5 for the hole time, occasionally. But I still have trouble doing some of my northern forms. I get winded by the last run. Are there any suggestions on breaking through this persistent problem?