Athletes who train over a long period for a certain sport change their bodies in very specific ways. The Denver Post is capturing such transformations over the next few weeks with photos showing how some athletes’ bodies react to their training. For instance, a ballerina is usually slender, but her calves look to be the size of grapefruits. For a rodeo cowboy, one arm might be muscular but average, while the other is ripped and almost twice the size. Colorado State University professor Matt Hickey says genetics also play a significant role in the way athletes’ bodies develop, but almost everybody responds to weight training and exercise, even into their 90s.

Even sedentary people will see changes if they take up cross-country biking, but if you’re serious about distance riding, be sure you know the proper way to ride—you may be surprised what you learn (Post). If you’re using an eletric-assist bike, however, you’re unlikely to see physical changes, and not everyone’s a fan of the motorized two-wheelers. Fort Collins officials are asking the public to weigh in on whether the e-bikes should be allowed on city trails (Coloradoan).