Electric Stimulation and Plantar Fasciitis

Use of low-frequency electrical stimulation for the treatment of plantar fasciitis. J Am Podiatr Med Assoc. 2009 Nov-Dec;99(6):481-8. Stratton M1, McPoil TG, Cornwall MW, Patrick K.

Recent research has discussed the use of low-frequency electrical stimulation to increase blood flow by eliciting muscular contraction in soft tissues. This randomized clinical trial examined the efficacy of low-frequency electrical stimulation combined with stretching exercises and foot orthoses in individuals diagnosed as having plantar fasciitis for less than 6 months.

Twenty-six participants aged 18 to 65 years diagnosed as having plantar fasciitis were randomly assigned to two treatment groups: a control group receiving only stretching and orthoses and a treatment group receiving low-frequency electrical stimulation in addition to stretching and orthoses. To assess treatment response, a visual analog scale was used to determine first-step morning pain, and changes in daily activity levels were monitored by using a validated outcome measure. All of the participants were assessed before starting treatment, after 4 weeks of treatment, and 3 months after the conclusion of treatment.

Participants in the control and experimental groups demonstrated pain reduction and improvements in functional activity levels after 4 weeks and 3 months.

Regardless of whether low-frequency electrical stimulation was used as an intervention, the use of plantar fascia-specific stretching and prefabricated foot orthoses provided short-term (3-month) pain relief and improvement in functional activity levels.

My comments:

McPoil and Cornwall were two of my favorite professors at NAU and most of what I know about foot anatomy and mechanics I learned from them.  Both treatment groups wore the same foot orthotics, both did the same plantar fascia stretching protocol described by DiGiovanni, but one group also did low rate TENS to the bottom of the foot at a rate of 10 pulses per second and at an intensity such that they felt a “moderate contraction or pulsing action that was comfortable.”  The TENS was performed once daily before they did their evening stretches.  No additional data was given with regard to pulse width, or amplitude used.

The conclusion of the paper was that both groups improved, such that the effectiveness of the TENS treatment was questionable and there was no significant difference between the groups.  However when I calculated the pain score improvement myself I found the TENS group decreased pain 35% at 4 weeks, compared to 23.9% in the control group, and at the 3 month follow up the TENS group pain was 68% improved while the control group was 54.1% improved.  The P-value for the difference between groups was not given but knowing what I know about TENS, a greater number of subjects likely would have shown a statistically significant treatment difference, and maybe the same would have happened if the TENS intensity was increased. In the TENS research low or uncontrolled intensity TENS is often questionable with regards to pain reduction, but if the machines are turned up to the strongest comfortable current consistent pain reductions are often found.

Still I am not a biggest fan of TENS because good quality electric stimulation machines can also be programed to do electric muscle stimulation (EMS) parameters that increase muscle strength. I would be very interested in seeing this study repeated using to target the foot intrinsic muscles, known to be weak in those with plantar fasciitis.  I currently prefer 10 seconds on, 50 seconds off for 12 minutes (10-50-12) with maximal pulse width and max tolerable amplitude using an electrode placement identical to that in this paper.  Besides improved muscle strengthening, EMS parameters have been shown to be superior to TENS for pain reduction as well.  The 10-50-12 EMS parameters would be almost identical to what world renowned sprint coach Charlie Francis favorite duty cycle (10-50-10) used for foot injuries in his sprint coaching book.  I just like to add 2 extra minutes to my treatment to get the intensity of the machine where I want it.  Also I would like to see the study repeated replacing DiGiovani’s stretches with comprehensive muscle strengthening program of the entire lower extremity.  A recent study just found basic calf strengthening, which was far from comprehensive, superior to Digiovani’s stretches.  In my physical therapy clinic the combination of EMS and strength exercises I am noticing  acceleration in the rate of recovery in my plantar fasciitis patients, most of whom have tried various foot stretches, and orthotics for months with little or no relief.

Updated 1/25/2016

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Chad Reilly is a Physical Therapist, obtaining his Master’s in Physical Therapy from Northern Arizona University. He graduated Summa Cum Laude with a B.S. Exercise Science also from NAU. He is a Certified Strength and Conditioning Specialist, and holds a USA Weightlifting Club Coach Certification as well as a NASM Personal Training Certificate. Chad completed his Yoga Teacher Training at Sampoorna Yoga in Goa, India.

9 thoughts on “Electric Stimulation and Plantar Fasciitis”

  1. A new article on shock wave therapy has demonstrated improvement in patients with plantar fasciitis. Pleasantly surprised. Don’t have a shock wave US so have never tried it.


    • Hi Ron, thanks for the link, I read that paper yesterday and I think I read one or two of the papers it references a few years ago. I’m a little skeptical of the results as I wonder if the shock wave therapy might just be a more theatrical than normal placebo effect, and that might be why it works better than a lesser placebo. The authors didn’t mention strengthening as a treatment for plantar fasciitis, which I think they should have. I don’t have any first hand experience with the shock wave therapy either, but I remember being interested in it. I went so far as to talk with a podiatrist that had a machine and he claimed it worked but that they never used it because insurance companies don’t reimburse for it, and I think the machine costs about $50,000 if memory serves correctly. Since then I started doing the EMS to the feet, strengthening the entire hips and legs, stretching the calves if needed, oh and NOT stretching the plantar fascia.

  2. This is interesting information. I got a cortisone shot a couple of years back in my left heel and don’t think I’ve been the same ever since. I feel as though my left foot is weaker and when I walk I have right knee pain, probably due to imbalances. Anyways, I’m interested in buying one of those ev906 units to use on my feet along with the other strengthening protocols you include in your other blogs. My only concern is that I’d rather see a professional in regards to using the end machine, as I don’t really know what I’m doing. It’s hard to know who uses the ems machines to treat plantar fasciitis, but I guess I could call some local physical therapists to find out. Thanks for the info!

    • For plantar fasciitis, now I would recommend a machine called the TwinStim4 by Rosco Medical. It’s only two channels, but more powerful, almost as powerful as the Globus units. For plantar fasciitis two channels are all you would need anyway and you can find them online for about $70. The EV906 quality became inconsistent, such that I can’t say that a new one would work as well as the older ones I was using when I blogged about them.

      In all honestly, you are probably better off learning to use the machine yourself. Physical Therapists are only slightly trained in the use of EMS anymore so I would not expect them to know more than you if you have read my blogs and started experimenting with your own machine. Definitely you want good electrodes otherwise it’s almost worthless. Good luck!

      Oh, and a number of my later blogs for plantar fasciitis talk about total leg and hip strengthening to go along with EMS of the foot intrinsics. I think SF5 would fit that bill really well if you don’t want to go to a gym. Good luck!

  3. Is it normal to be able to up a lot higher in current on the bad foot than on the good foot?My left foot is the one with heel pain and I can go up to 50 (using Evo 906) on that foot, while the right foot only tolerates about 27.

    • Hi Reinaldo,

      It might depend on which wire you are putting on which part of the foot with the EV906. Since it’s a “asymmetric” bi-phasic square wave current, the black wire will feel stronger. In my experience it feels about 30% stronger, so that could explain some difference. Also sometimes one side of your body has nerves closer to the skin, or you just put the electrode in a more/less favorable spot, so it feels different, and it’s fairly common that it happens. The injured side could have some nerve damage making it less sensitive, or the muscles are weaker on that side, causing or resulting from the plantar fasciitis, so that it takes more stimulation to get an equal amount of muscle contraction. It could be a combination of the factors I just listed, so I wouldn’t say it’s “normal” to have that great a difference, but it’s not uncommon, and probably not a big deal. I would expect over a few weeks time for you to tolerate a greater intensity of electric stimulation on both sides, and the the differences between sides to lessen. I hope that helps!



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