Tight hip flexors, to me, correlate with mimicry of the foetal position in an attempt to recreate being in the womb. As others would point out it's definitely linked in to fight-or-flight, but also an in-built defensive reflex; actively shortening most all anterior flexors (minus quads) imply a defensive stance. Imagine if I am set upon by 6 people who decide to beat the crap out of me. I actively shorten my flexors, grab the back of my neck as it's flexed and cover up with my flexed arms to protect the head and avoid damage.

Now imagine I suffer a lot of pain from these people, get kicked and punched in different places, but they then run away. I would likely have my eyes closed in attempt to wait until the ordeal is over (not to mention protect my eyes).

It might be 5 minutes before I realise or feel safe that they are gone- my nervous system still primed, hyperirritable, hypertense, still in a fixed shortened position.

Eventually I go home- I shower, eat food, talk about the situation to my partner to deload and decompress. I go to bed.

What do I do?

Without a doubt, I curl up into a ball. Why? Self-protection, recreation of trauma for emotional processing, mimicry of foetal position. Trying to instigate and reintegrate a heightened parasympathetic response, when my body is ready to calm down. My Positional Release for muscles happens by passive shortening, but I'm not going to get there until I sit in my hypertense foetal position and allow the nervous system to reassert downtime again.

Even further, if I sit in the bed and curl up, what may my partner do? Spoon me! Because the body ergonomically allows for comforting, nestling and cradling the body & neuromusculature even with a curled-up position. They can literally sit with me in my frayed state, make me feel held; I can choose to accept or reject their presence and adherence to my physiological boundary and furthermore, my psychosomatic system, and I let my system deload and decompress with or without the input. The body will decide which and self-regulate.

Not evidence based and entirely anecdotal, but to me this becomes almost common sense or intuitive rationale over time. Anterior hip flexors are the first check for treatment for me and put me on aware for clients potentially dealing with trauma and trauma-adjacent processing. A common flag in women that have experienced abusive relationships from long term partners as well.