Join Coach Patrick from Endurance Nation (www.endurancenation.us) for another weekly endurance podcast. This week Coach P interviews Rob Sleamaker from [Vasatrainer.com](www.vasatrainer.com) to learn more about the Vasa Trainer for swim training. Improving your swimming is one of the hardest parts of becoming a better triathlete — mainly because you can’t really get a sense of what…