I’m an introvert. I don’t like fairs, carnivals, airports, or malls. I don’t particularly like loud, overcrowded, sweaty fitness classes, which is ironic considering I’ve taught thousands of them. But despite my personal preference for a low-key vibe, group fitness environments can provide the extra motivation and accountability some people need to thrive. One thing I have learned over and over again, as both a student and a coach, is that when it comes to reaching and staying at your...