It's been well documented on this blog that I'm not big fan of static stretching (in fact, you can read that here). But, if you were to watch one of my sessions with a client, sure enough, you'd see a few movements that *look* like stretching.
Now, before you write me off and chant "liar, liar, barbells on fire," allow me to provide my reasoning. For many people, the reason they're tight has nothing to do with that muscle or body part. Rather, it's weakness in their surrounding parts.
To start, it's probably best to think about a toddler, as they have no mobility restrictions and you wouldn't necessarily think that they need to stretch. Yet, fast forward 15-20 years down the road, and all of a sudden that same person is tight and has lost the ability to get into certain movements/positions.
Why does that happen? The way you sit, certain repetitive movements you make, the way you breathe, and other variables all contribute to the way your body, and certain muscles, are shaped. With all of this going on, it's pretty easy to see why sitting on the floor and stretching your hamstrings for a few seconds isn't really going to have a lasting effect. In fact, I liken static stretching to mopping up a wet floor....when it's the ceiling that's leaking.
Now, this isn't to say that static stretching doesn't work. Instead, I'm saying static stretching alone doesn't work! If you have tight hips or hamstrings, you need to address the reason why you're tight, and what exactly those "tight" muscles are compensating for. Most of the stretching I do with my clients is called PNF (proprioceptive neuromuscular facilitation), which is a way of making your body think whatever weakness you have is gone. If you think about a slingshot, you need a steady base in order to be able to use that rubber band. The PNF stretching I perform with my clients makes their brains believe that their slingshot has a steadier base, so that they can use those rubber bands and get into positions that weren't possible when they walked in.
Next, we usually do plenty of exercises and reps to address the positions or weaknesses that usually made them tight in that particular area. Glute bridges are almost always prescribed when someone is tight in their hips or hamstrings, as well as plenty of core work.
What came first: the tightness or the weakness? Well, that's the million dollar question that doesn't need to be answered. The body is much more than the sum of its parts, and you need to fix both sides of the equation, in order to get back to where you need to be.