It used to be common knowledge that you were supposed to stretch before and after your workouts. That was how you “warmed up your muscles” and prepared them for activity.
Oh how things in the health field change.
More recent studies have shown that static (or stationary) stretching increases running time in runners, as well as lowers the 1 repetition maximum in power lifters.
Receptors in your muscles are being told the muscle is elongated, so when they contract, they do not contract to the same shortness as they would do had they not been elongated in the first place.
To add insult to injury – most studies have shown that static stretching actually does very little to increase range of motion through the joints (“flexibility”) in the first place! Most of the stretch is just being felt by the receptors but doing very little to change the way you move.
So, now if you're saying to yourself “I have very tight hamstrings!” or calves, or shoulders or whatever muscle you're thinking about right now.... I want you to ask yourself “WHY?!”
Are they right in the first place? Is it disuse? Overuse? Imbalance?
There is a reason that the muscles are tight and don't feel “normal”, and this underlying cause is the reason you have tightness in your body.
Address the underlying concern, and the tightness will disappear on it's own!