As you get older, your lean body mass decreases. This includes changes to your tendons and ligaments that result in less flexibility and a more limited range of motion. In order to exercise safely, it’s important not to move outside of your comfortable range of motion. Some people might be totally fine squatting well below their knees, while others simply don’t have the hip mobility. If you have limited mobility, you could be risking an injury if you accidentally move past your body’s range. In order to increase your mobility and range of motion — and decrease your risk of injury — you’re going to need to stretch. There’s some debate about whether you should ever stretch before a workout, but there are zero drawbacks to stretching after. Stretching after a workout can also help you properly cool down. The slow, gentle movements will assist your heart to slow its pace gradually, rather than you coming to a complete stop that could cause lightheadedness.