I like a good pump like the next person, but I also like to measure fitness in different ways. For some people – including me – being fit can mean being more flexible and mobile, and lifting dumbbells and barbells won't help you achieve that. The good news is that if you dedicate just a few minutes a day to stretching, you can get a lot more flexible quickly.Being flexible helps at any age, but it's especially useful to help people keep fit over 40. Even if you aren't 40 yet, you should consider doing more stretching as it can make you less pron...