Surface Electromyography = sEMG.
OK, I’m a self-admitted data geek, but I don’t know of any other physical therapist, or anyone else for that matter, using this technology in Greenwood, Seattle, or even the greater Puget Sound area for this purpose. It really provides a goldmine of information about muscle recruitment, imbalance, timing patterns, pre/post treatment differences, training, etc.
Here is a good article by Glenn Kasman regarding sEMG.
I used to prowl research articles (still do) to find the best ways to elicit the best contractions from key muscles. The researchers typically used sEMG, and there was always individual variance regarding which exercises worked best. We had two, very basic sEMG units for muscular biofeedback, but I kept thinking it would be great to have a research-quality sEMG unit so that I could find out how to precisely evaluate muscle recruitment quantity and patterns in functional movements, even while running on a treadmill.
So we dropped big money on a wireless Noraxon 2400T Telemyo unit, along with a big screen HDTV to show realtime data and graphing so we can see it while doing anything, anywhere in our gym. I can hook up 8 different muscles at one time. We also have digital goniometers and accelerometers that plug into the same system.
I’ve had more big learning moments, for both myself and my patients, than with any other tool or technique that I’ve ever learned or used. It eliminates a lot of guessing. I know if an exercise is targeting that gluteus medius or not, or if someone can actually bring the same level of muscle recruitment from an exercise into an actual activity. If they can’t, then we use the same system to teach them how by using different physical or verbal cues and realtime graphical feedback. You would think a hip extension exercise would work the gluteus maximus well, but if you’ve got a weak one, there’s a good chance that something is inhibiting it’s recruitment, so a standard exercise may not even touch it.
Combining this with an evaluation and a digital video analysis gives me a incredible information about what is happening when someone is actually doing a movement that causes pain.
If a joint is stuck or moving incorrectly, we can have impaired muscle recruitment. A classic example is a sacroiliac joint that is stuck in anterior or posterior rotation, and not moving during a walking or running gait. This can neurologically inhibit the gluteus medius (our old friend), which leads to further hip and core stress, as well as SI joint dysfunction, creating a vicious cycle that can be tough to break. I can’t tell you how many IT band problems I’ve seen caused by this scenario. So as a manual therapist, I mobilize the SI joint in the proper direction, regain normal range of motion, and voila! the glute medius fires normally again. We can see it immediately on the big screen. In that case, we then focus on specific core, pelvis and hip exercises and flexibility to ensure that the SI joint is properly controlled intrinsically.
Same thing can happen in any areas of the spine, especially the neck (cervical) and low back (lumbar).
Usually a muscle that gets chronically strained is weak. Is it really? Manual muscle testing performed by a good physical therapist can give us some clues, but not always the final answer. I keep referring to the gluteus medius because I’ve done more sEMG testing on that muscle during one of my Run Labs or Runner’s Clinics than any other muscle. A runner can have a glute medius of steel with a manual muscle test, but have it be completely useless in a running motion. What’s up with that? Well that’s what I try to find out. If it is just a matter of an uncoordinated muscle then we can use the sEMG in biofeedback mode to help connect your brain to your, um, butt. Sometimes the movement is too complex to do that right away, so we break down the movement into simpler parts, until the sEMG shows us that the muscle is engaging. Then the patient works that exercise on their own, and returns to the clinic periodically to progress to the next level, until ultimately they are back to running while, literally, getting their butt in gear!
For some people it happens quickly, that’s hitting a home run. Like a patient I had who had been unable to run or even hike for literally years because of a knee problem stemming from a nonfunctional (you guessed it) gluteus medius. He already knew that, he had been working on it for a long time with another physical therapist and in Pilates. He was doing the right thing. But his brain had lost the normal neuromuscular recruitment pattern and it never made substantial progress. So I hooked him up. We were nearing the end of a multiple-hour Run Lab, when I took a bathroom break. I left him working on an exercise that should have engaged the glute medius, but wasn’t really. When I returned he was giddy! Just by playing with how he was trying to tighten the muscle, while watching how much recruitment he was acheiving on the big-screen, he suddenly made the connection. He then practiced it until he could engage the muscle at will during the exercise, then even while walking. He was soon able to return to hiking, don’t know if he ever started running again. I wish I could take all of the credit for his case, but he actually stumbled upon the solution almost on his own, facilitated by my knowledge and the sEMG tecnhnology.
I’ve also used this for people with excessive muscle recruitment. We measure and monitor key postural muscles, usually in the neck and back, and look for muscles with too much recruitment. We then work on changing their posture until we get a good, functional position with minimal muscle engagement. This is a great tool for people with repetitive strain disorders or postural strains from sitting, working positions, especially from driving or working on a computer (wait til I blog about that!).
I’ve used sEMG to teach different progressive relaxation techniques to patients with headaches due to muscle tension as well.
Seems like I talk about the butt a bit too much, but it’s a key muscle group. So how about something else? Other great uses have been measuring and changing recruitment and timing patterns for groups of muscles like;
-Upper, middle, and lower trapezius with shoulder external rotators and posterior deltoid for shoulder problems.
-Glute medius, maximus and TFL for hip/knee problems. Or glutes and hamstrings.
-Glutes, VMO and VLO for knee and patellofemoral issues.
-gastrocnemius, soleus and tibialis anterior for ankle issues.
I originally started using this with runners because I realized that it was impossible to accurately assess their running muscle function if they were not actually running while being tested. Now I use this technique with a wide range of injuries, not just athletic ones. I can use it to help with posture, lifting mechanics, rotator cuff problems, etc. etc. It’s interesting to use in our Cycling Clinic as well!
The more I play with this the more valuable it becomes. I learn many little quirky things about my patients, or at least how their body works that is a bit out of the ordinary, not according to the textbooks.
I’m planning on researching how different kinds of foot strikes and custom orthotics affect specific muscle recruitment. Stay tuned for that.
sEMG is an awesome tool to have in my toolbag. It is just one of my tools, but it’s one of my favorites!
Cheers,