“All work and no play” may not make Jack a dull boy, but it certainly does him no health favors. A 2013 study by the Centers for Disease Control and Prevention indicated that nearly 80 percent of North American adults don’t get the recommended amount of exercise each week. That’s not surprising, really. As a whole, the world is more sedentary than it has ever been, with modern teens being about as active as 60-year-olds. That lack of physical activity brings with it some serious health issues, like heart disease and obesity. Not only that, but people who don’t exercise and