In one sentence, describe what the following article is about:

Stretching your muscles at least once a day will increase your flexibility and mobility, which will allow you to handle the ever-changing demands of a hike. Stretching also helps to expand the muscles of your rib cage and diaphragm, which will help develop a greater lung capacity for hiking.Stretching also helps release tightness in your muscles after a long hike or a challenging workout.
Stretch regularly to improve flexibility and lung capacity.