Interview with Dr. Jess Greaux on the Noraxon system

Written by Roger White on . Posted in Blog

Dr. Jess Greaux founded Innersport Chiropractic in Berkeley, California, with a focus on sports injury management for those seeking an active lifestyle.  Dr. Greaux is an Active Release Techniques (ART) instructor, and a certified ART Ironman Provider.  In Dr. Greaux’s clinic, she uses Noraxon, which measures EMG, pressure mapping, and real-time 3D video analysis.  Dr. Greaux had some time in her busy schedule to answer some questions about Noraxon.

Dr. Greaux, your clinic has a specialization in sports performance. Also unique to your practice is your use of surface EMG using the Noraxon system. Can you explain what sEMG is and how you utilize it in your practice?

sEMG tells us which muscles are firing when (or not!)  We learn muscle sequencing and firing patterns while someone is running, biking, squatting, jumping, etc.  We found most athletes are extremely good compensators, mimicking near perfect form.  However, once we look at the sEMG data synced with video, we are learning how they are accomplishing the technique, which usually involves compensatory, asymmetrical firing patterns.  It’s a BS-ometer.  

Very interesting stuff! There are constantly new releases of technology on the sports performance market that measure different aspects of athlete performance. However, interpretation of this data is not always simple.   In my experience for example, it took a period of months to be able to understand what HRV data meant, and how I would change athlete training as a result. Thus interpreting the data is quite nuanced, and usually the black and white process that every coach would hope for.

How would you describe your learning curve with the Noraxon system? How long did it take for you to get useful data? Who guided you to be able to gain useful information from this system?

We are still learning how sEMG can help us. Seems like the applications are endless.  Noraxon sent reps to work with us one-on-one with our own clients.  I’ve also learned some analysis through Chris Powers during his courses at his Movement Performance Lab.   And, then it’s research and trial and error.  We’ve learned a lot by experimenting with patients and ourselves.  

Do you think there is a clear-cut connection between Noraxon data with athletes doing isolated movements vs. when they are doing dynamic movements like a sprint?

Nothing is ever clear-cut.  Or not as much as we’d like when we are dealing with the human body.  However, yes, we are finding that if someone has difficulty with activating the glute max doing a supine bridge, then it has carried over to running.  In fact, that’s why sEMG is so useful.  We notice they can’t fire the glute max during running, then we work backwards to find WHICH exercise they can be successful in firing the glute max.  Sometimes we may only find 1 exercise where they are successful, then we eventually work forward with more dynamic exercises to get them to running with glute activation.  


Analysis before treatment intervention




Post-treatment analysis showing improvements

Many therapists do assessments with patients on tables, some also include movements such as squats or other exercises. In your experience using sEMG to quantify the assessment, does the patient’s position make a difference? In other words, does a traditional table assessment show similar patterns as those when doing dynamic movements such as squats etc? What about, for example, if someone shows impaired glute firing doing a glute bridge (or another exercise you use to assess), do you expect impaired glute firing during a full effort sprint?

I have to say the sEMG shows us more consistency across various movements vs. movement screens.  However, with that said, every patient is different and not everyone is consistent.  And that is why we use sEMG, to see what THAT particular patient’s compensatory patterns are.  It takes out the cookie-cutter approach to assessment and treatment.
Along with the glutes, it’s common to see trainers and therapists talking about glutes not firing and then” turning them on” or “activating” them with exercises or therapy. Based on your data, can these exercises, such as a bridge, show noticeable changes on sEMG?

Again, everyone is different.  We have given exercises to patients to get the glutes firing, only to learn they still compensate and fire hamstrings, or even glute med instead.  So, this is where we find the exercise that THEY are successful in to fire the right muscles at the right time.  Once we find the exercise that makes them successful, we have them perform the exercise while watching the sEMG data to perfect it.  Then we move on to more dynamic exercises eventually working our way to their particular sport.  

Noraxon is a data gold mine! I’ve seen a professional runner’s report that was several hundred pages long. For someone like a runner, how do you filter this data report to get the most useful information to direct your treatments for that athlete?

It’s all a process.  We don’t use sEMG alone.  We look at videos and force time plots and foot pressure to learn the whole picture.  Many of us have several dysfunctions and asymmetries.  Using sEMG synced with video and other technology we are able to learn the key problem areas that may be causing more than one dysfunction.  Basically we are weeding out the bad data from the useful data by looking at more than one system.

For a new patient/athlete coming to see you, can you walk us through what they would go through in the initial session, and how you use sEMG on the subsequent sessions is used to guide treatment?


Foot Pressure Mapping

We have several services.  Some come to us for an injury in which they go through a diagnostic exam.  Then we put them through a data collection session with one of our staff.  The patient and I will review the data at the next appointment in which we will determine course of treatment.  Some we go right into gait retraining if they don’t need treatment, but most people need treatment for adhesions that can alter mechanics.  We’ve used sEMG pre/post ART treatment with amazing results.  It verifies our treatment approach.

Sometimes runners and cyclists come to us just for a run analysis or bike fit.  We use sEMG during the analysis.  Some continue to schedule gait or pedal retraining where we use sEMG as biofeedback.  It’s a very power biofeedback tool. 

In addition to foot pressure for runners, you also do seat pressure analysis for cyclists. If a cyclist comes to your clinic of knee pain during rides, what might your assessment using seat analysis look like?



Saddle Pressure Mapping

Yes, we love using saddle and foot pressure for cyclists along with sEMG.   These two technologies allow us to learn HOW the body is responding to a change in fit and treatment!  For instance, we make a change to the fit, does the body perform more symmetrical?  Do they get better glute activation?  When I see dysfunction on the bike and they are unable to load one sit bone on the saddle (seen on the saddle pressure), and then I treat the thoracic spine or hip rotators, does it improve the saddle pressure data? If it does, then I know which exercises to give them and what to treat with ART, Graston, or Myofascial Decompression.  Again, it’s a BS-ometer.  Test, treat, and retest.   Many bike fit systems look only at numbers or knee alignment.  However, the angle measurements do not tell us HOW they are accomplishing the movement or alignment.  sEMG and saddle/foot pressure does.  We learn if the knee alignment looks better because they are activating the muscles correctly to accomplish good technique or are they using the wrong muscles at the wrong time.  Or are they able to get good knee alignment because they are shifting their weight to one side and twisting on the saddle.   This is where treatment is vital.  If they are compensating to “look” good on the bike, then we can treat so they don’t have to compensate.  I think this is what is missing in most bike fits.  The BS-ometer.  🙂

(On Dr. Greaux’s website, she wrote up a case study report on how a high school runner was helped using what she talked about. )

Amazing stuff Dr. Greaux. Thank you for taking time and sharing. This is incredible.

You can learn more about Dr. Jess Greaux’s clinic and extensive services at and her own blog The Straight Scoop




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