Neat study proposal!  I am unable to help you with potential measures or relevant literature at this time.  However, I have another related question:  Does chronic constriction/spasm of the psoas lead to hypertension?  Please keep in touch.

Sounds like a great study. I have wondered how connected lower back pain/surgeries were connected to stress. Just an observation that people who live stressful lives (or have been traumatized) seem to also have significant lower back issues. I look forward to your research. I am wondering if there is at least an assessment available to help track down your possible correlation.

Thank you, Wayne. I may have shifted the focus of my study to grounded theory on the role of the psoas in fight or flight, since I've not found any literature to back up this idea. I'll keep posting here as I move forward. I also haven't found a specific way to measure psoas activity, which would be very desirable in a quantitative study.

You certainly are on to something.... My bodywork staff in the military PTSD clinic routinely reported the PTSD soldiers came in with locked psoas muscles and the deep tissue massage therapists thought it was part of the cause of the epidemic erectile dysfunction and apnea symptoms. Psoas release work was very helpful.

Psoas tension relates to early developmental issues of safety and rage. We see this quite clearly in psychedelic work (MDMA & PTSD). Naturally more recent insults pile onto those accumulated and enshrined in chronic tension of the psoas. The idea of measuring psoas tension is brilliant, but the capacity to do so is quite complex and though I wish I could help you, I can only follow your progress with fascination and respect!

My background includes training as a Postural Integration practitioner and it was Jack Painter (the originator of this approach) who first made me exquisitely aware of my own psoas and those of my patients.

I use range of motion to test muscle tension.  This method has it's drawbacks, but I haven't found a better way to measure muscle tension. 

I have been working on the idea that chronic anxiety and muscle tension in adults may start in childhood, creating increasingly poor postures and disfunctions as they age, culminating in increasing anxiety, pain and balance problems.

I'm looking forward to seeing your research!

I wonder if an EMG device would allow quantitative measures. Electrode placement is of course a difficult choice in an internal muscle. There is an electrode used in anal sphincter training for incontinence that might be useful- a measure of resting level might be different in PTSD persons since my PTSD soldiers called this their "pucker muscle". Also a subjective rating by a skilled structural body therapist or Rolfer might add another measure.

Looks like I forgot to check here more often! Several of your comments will be very helpful in my lit review and/or discussion. I gave up on trying to measure muscle tension in the psoas...beyond my capacity at the dissertation level. My study has ended up being RCT on whether a specific muscle relaxation technique reduces symptoms for people with co-occurring PTSD and non-specific chronic low-back pain (big co-occurrence and some evidence to link both to muscle tension). I'm currently recruiting for participants, which is possibly my biggest challenge at the moment.

Ratings by structural body workers? The anal sphincter electrode system might be an option?

Hello, I do not have the answer to your question but being a veteran who suffered from PTSD as well as severe anxiety disorder for the past 8 years, I became practically crippled. I was able to find an osteopath who discovered that I had many underlying childhood perceptions that affect the manner in which my body reacts to trauma. Also, she treats my Chapman points and I am now able to walk and am slowly on the path to recovery. She has discovered that my psoas plays a vital connection to the Chapman points that are associated with the lower back, IT bands and the feet. I hope this helps.

This is my area of research as well, we should definitely connect. I'm using biomechanical tests as they are the only thing we have any validity studies on right now and are used clinically, though there is a difference between range of motion and tension. Have you published your research yet?