Before we get down on one knee to stretch our hip flexors or stick our legs up on a chair to release our hamstrings, it's worth considering whether they ought to be released in the first place.
After all, what if they are only tight because they are offering some protective benefit?
For example, in the case of the hamstrings being tight, what if they are only this way because they are offering support to the SI joint?
If the SI joint is unstable (for example, after labour), force from the hamstrings can lead to an increase in tension of the ligaments around the joint. This increase in tension helps to provide stabilisation.
And if this is the case, then the hamstrings will feel tight and short.
So should we actually free up a hamstring that is providing stability for the joint?
Maybe. Maybe not.
It's just always worth considering WHY a muscle is tight and that in some cases it may actually be beneficial for it to remain that way.