What We Do for Plantar Fasciitis, and Why:
At Absolute Physical Therapy, we focus on increasing muscle hypertrophy of the foot intrinsics, which are known to be weak and atrophied in conditions such as plantar fasciitis and posterior tibial tendinopathy. This weakness likely contributes to a number of other lower extremity problems, including medial tibial stress syndrome, patellofemoral pain, etc.
Unlike most other physical therapy clinics, I prefer to strengthen the intrinsic foot muscles with the use of Electric Muscle Stimulation, which gives the patient a superior intrinsic foot muscle contraction compared to muscle contractions accomplished through typical physical therapy foot strengthening exercises.
Another strategy we use in addition to strengthening intrinsic foot muscles, is to target strengthening the hip abductors and extensors, which are also known to be weaker in those with plantar fasciitis and other similar conditions.
Plantar Fasciitis and Foot Muscle Atrophy
A 2012 study used an MRI to estimate the volume of the tibialis posterior and plantar intrinsic foot muscles in healthy and chronic plantar fasciitis limbs. It was found that while the total volume of plantar intrinsic foot muscles was similar in healthy and plantar fasciitis feet, atrophy of the forefoot plantar intrinsic foot muscles may contribute to plantar fasciitis by destabilizing the medial longitudinal arch.
Researcher’s noted that foot intrinsic muscles were 5% smaller on the painful foot of people with plantar fasciitis. In this study they compared the good foot to the bad foot on the same person; however, I would expect the relative atrophy to be greater when compared to healthy controls. In my physical therapy office, I have noticed people with plantar fasciitis haven weakness in both legs, with the painful side often being the worst. Even so, I still find this to be a very interesting study. The authors point out that plantar fasciitis isn’t just an injury associated with a loss of range of motion, but one associated with a loss of foot intrinsic muscle strength that can benefit from strengthening, as well as typical rehabilitation programs that focus solely on morning foot stretches and orthotics (which turn out to do a lot less good than people think), was an interesting point.
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An article that I recently commented on in my blog, stated that high load strength training improves outcome in patients with plantar fasciitis. The study investigated the effectiveness of shoe inserts and plantar fascia-specific stretching vs. shoe inserts and high-load strength training in patients with plantar fasciitis. The strength group protocol used in the study was three sets of 12 reps, worked up to five sets of eight reps of single leg calf raises using books in a backpack to increase resistance performed once every other day. The stretching program was compared to was performed three times per day every day, and is probably the industry standard as described by Digiovanni. At 12 months, results showed that the Foot Function Index was 22 points in the strength group and 16 points in the stretch group.
I have been stressing importance of strength training in place of and in addition to stretch, depending on whether the patient has too much range of motion or too little in various joints of the foot. I began doing this based on a number of studies showing muscle weakness and atrophy, as well as from my experience in my physical therapy clinic treating patients with plantar fasciitis, but this is the first study ever addressing the effects of strength training in the treatment of plantar fasciitis. Those with plantar fasciitis generally have tight calves; some stretching is often a good idea, and strength vs stretch needn’t be an either/or affair. However, only stretching has been shown to inhibit muscle strength, and good strength training exercises performed through a full range of motion often stretch while they strengthen, giving a two for one effect.
The unfortunate thing for the profession is that while this study is new and pertinent it probably won’t be seen in the average physical therapy clinic for another 15-20 years, and by then the research will be on to something better, with most therapists still hung up on the latest fad in soft tissue mobilization or needle poking. Evidence based medicine really should be more than a catchphrase.
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Importance of Supportive Intrinsic Foot Muscles
A fascinating study from 2003, demonstrated that the smaller muscles inside the foot are very important for supporting the foot arch. The study demonstrated this by injecting lidocaine into the nerve controlling those muscles, thus temporarily paralyzing them. Doing so they found the the navicular bone drop (used to measure foot arch) increased from ~6mm to 9 mm (a 50% increase). Thus foot muscle weakness in real life would significantly increase stress on other arch supporting structures including the plantar fascia and posterior tibial tendon, likely contributing to plantar fasciitis and posterior tibial tendinitis, respectively.
This fits in with other studies I have blogged on, that found patients with plantar fasciitis do, in fact, have smaller and weaker foot intrinsic muscles in addition to tighter and weaker calf muscles. This would also explain why current treatment protocols focusing on stretch and orthotics but ignoring strength training are only marginally successful. So the take home message for those with foot pain, physical therapists, and others treating foot injuries, is that foot intrinsic muscle strength needs to be restored. This strength will lessen stress on the foot arch and help promote optimal recovery from conditions like plantar fasciitis and posterior tibial tendinitis. It should also go a long way towards preventing more debilitating conditions down the road, such as acquired flat foot deformity.
Check out my blog to read more about: Intrinsic Foot Muscles and Plantar Fasciitis
Why We Use EMS
In my physical therapy clinic, by using 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.
A 2009 study experimented with the use of low-frequency electrical stimulation, in order to increase blood flow by eliciting muscular contraction of the soft tissue for the treatment of plantar fasciitis. 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 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 four weeks, compared to 23.9% in the control group, and at the three 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 programmed to do electric muscle stimulation (EMS) parameters that increase muscle strength. 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 two extra minutes to my treatment to get the intensity of the machine where I want it.
Check out my blog to read more about EMS for Strengthening Muscles in Patients with Plantar Fasciitis
I’m of the opinion that plantar fasciitis should be treated more like tendinopathy. I notice a pretty good benefit from both of my approaches clinically, but as of yet, there is no research on either strengthening nor EMS for plantar fasciitis. The similarities of the condition with various tendinopathy conditions, along with my outcomes, makes me think it’s worth pursuing.
For plantar fasciitis, I think the best course of action is to:
1. Strengthen muscles of the lower leg and foot with a combination of progressive resistance exercise for the larger muscles.
2. Strengthen intrinsic foot muscles with electric muscle stimulation, vs. short foot exercises.
There have been a number of recent studies on the “short foot exercise.” Standing on one leg, you try to shorten your foot by pulling the ball of your foot towards your heel while keeping your toes relaxed. This attempts to isolate the foot intrinsic muscles rather than extrinsic toe flexors , which work more with towel bunch type exercises. Having tried the exercise myself it did feel like my foot muscles were working, but I also noticed I was was using my tibialis anterior and and posterior tibialis to raise the arch of my foot, so I don’t think it’s entirely isolating the foot intrinsic muscles. Also, the intensity of intrinsic muscle contraction feels well inferior to what I get with electric muscle stimulation (EMS) of those muscles. Lastly, with EMS, isolation of the foot intrinsic muscles is easy.
For EMS electrode placement, for a four-channel device, I place channel one and two on the ball and heel of each foot, channel three split between each tibialis anterior, and channel four split between each tibialis posterior.
For EMS setting guidelines, I currently prefer 10 seconds on, 50 seconds off for 12 minutes (10-50-12) with maximal pulse width and max tolerable amplitude.
What We Don’t Do for Plantar Fasciitis, and Why:
Our Main Focus Is Not Stretching
This paper is relatively famous among physical therapists with relation to the treatment of plantar fasciitis. Researchers found plantar fascia specific stretches (crossing your leg and bending your toes backwards with your hand 10 times 10 seconds three times per day) to be more effective at decreasing pain than equal time on calf stretches; however, I have several problems with the conclusions in spite of the positive outcomes with plantar fascia specific stretches.
First: other research has found that the plantar fascia isn’t particularly tight in patients with plantar fasciitis, while the calf muscles are. This being true, even if the results of this study are correct with regards to pain reduction, you are maybe over stretching a tissue that isn’t tight (plantar fascia), while leaving the one that is tight (calf muscles) abnormally short.
Second: the results of plantar fascia specific stretches, even if better than calf stretches, aren’t particularly impressive. This study only showed a combined pain reduction of 19% after eight weeks of treatment, compared to 13% for the calf stretches.
Third: a recent study found relatively simple strengthening exercises were significantly more effective at treating plantar fasciitis when performed once every other day. These exercises were more effective than these plantar fascia specific stretches performed three times per day every day. Even that study did not address strengthening of foot intrinsic muscles, and hip abductors and extensors known to be weaker in those with plantar fasciitis and other similar conditions.
Last: the plantar fascia is a passive structure that supports the arch of the foot. If stretched out, other structures (muscles, tendons, and ligaments) logically must either take up that load or the foot will flatten. This likely leads to other problems, including posterior tibial tendinopathy; potentially resulting down the road in acquired flat foot deformity. So while plantar fascia stretches may be the current conventional wisdom, conventional wisdom is often long on convention and short on wisdom. When developing my physical therapy protocols, 10 times out of 10 I will choose more current research, applied logic, and sound reasoning over conventional wisdom.
So what do we do instead? If the calf muscles are tight we do stretch them, but more importantly we strengthen the all the muscles (intrinsic and extrinsic, including the hips) that support the foot arch with a combination of exercise and EMS; thus, improving overall fitness while we take the stress off the plantar fascia. Besides strengthening, EMS has the great side effect of immediately reducing pain.
The plantar fascia is a passive structure that supports the arch of the foot, such that if it is loose, either the muscles will have to work harder, or the arch will collapse slightly, neither of which seem to be a good idea. As such it would be better to just stretch the calves, which have been shown to be tight in those with plantar fasciitis, while the plantar fascia itself has been found to be of normal length.
Check out my blog to read more about Stretching and Plantar Fasciitis
We Don’t Recommend Cortisone Injections
I’ve advised against cortisone injections for tendon injuries for a long time. In my opinion, they are about the only thing you shouldn’t do. Everything else is at worst a pseudoscientific waste of time, but cortisone shots leave tendons worse off than no treatment at all. The plantar fascia has not historically been considered a tendon; however, it is now being described as an aponeurosis, which is a “white flattened ribbon like tendinous expansion”. In my experience, it responds considerably better to tendinitis type strengthening protocols than it does to more traditional treatments of stretches and orthotics.
When stretch and orthotics fail to fully resolve symptoms, as they frequently do, the next step is often one or more cortisone injections. Cortisone is known as a catabolic steroid, which is the opposite of an anabolic steroid that athletes take to make their muscles stronger. Catabolic steroids make muscles and tendons weaker; this has been known for decades. To me, this just doesn’t sound like a very smart thing to do for a condition known to result from intrinsic foot muscle weakness just adjacent to and/or around the plantar fascia.
This study found that there were not any factors (including BMI, high or low arches, amount of time spent standing, etc.) significantly associated with plantar fascia rupture, with the exception of cortisone injections.It was also seen that the risk with cortisone was considerable. They found that a single cortisone injection to the plantar fascia increased the risk of rupture by 18.8 times (not 18% but 1,880%) which is pretty huge in medical terms; two injections increased the risk 34.6 times; and three or more injections increased the risk of plantar fascia rupture a whopping 125.8 times!
With plantar fasciitis being a very painful condition, people understandably want a quick fix. Nonetheless, a cortisone shot on average only gives temporary comfort at the expense of increased risk of long term pain. This study showed a very high increase in risk of plantar fascia rupture which can lead to permanent disability. So my advice is: just don’t do it. It’s much better to tough it out for a few weeks, do your physical therapy exercises which hopefully include a fair amount of foot, leg, and hip strengthening exercises and EMS; as opposed to just stretching, orthotics, and various soft tissue techniques (which are so 1990s) but still better than a cortisone injection.
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