Swimming can be one of the safest and most effective forms of cardio. Whether you are trying to lean out or to get stronger, swimming is easy on the joints, scalable to your goals and an excellent way to connect your brain, breath and body. But it can be a big drag (literally) if your stroke or breath are off. Michael Bonella, Claire Love and Megan Nazareno are three of San Francisco's top swim coaches and personal trainers. I asked them "What is the most common issue you encounter with form and how do you help your clients through it?"