The Link Between Foot Muscles & Plantar Fasciitis in Runners
Plantar fasciitis is one of the most common injuries runners experience. It has long been speculated that weakness of the intrinsic foot muscles is associated with the onset of plantar fasciitis. See below for the four layers of the foot-with the first two layers showing the intrinsic foot muscles, layer three the plantar fasciia, and layer 4 the skin.
Many sufferers of plantar fasciitis will ask me during physiotherapy consultations if they need to strengthen their foot muscles in order to improve their condition. I believe that many runners just intuitively sense that with their pain they have likely lost foot muscle strength, and therefore regaining it must be part of the rehabilitation. My response when asked by plantar fasciitis sufferers if they need to strengthen their foot muscles has consistently been ‘yes’ for the vast majority of cases.
Many sufferers of plantar fasciitis will ask if they need to strengthen their foot muscles. #performbetter @pogophysio Click To TweetDoes Intrinsic Foot Muscle Dysfunction Contribute to the Onset of Plantar Fasciitis?
A recent study proposed that atrophy (reduction in muscle size, or technically muscle ‘volume’) of the intrinsic fore-foot muscles might contribute to plantar fasciitis. The proposed mechanism was that a reduction in intrinsic foot muscle size may negatively affect the ‘arch’ (medial longitudinal arch) by destabilizing it.
However, intrinsic foot muscle volume difference between individuals with plantar fasciitis and those without plantar fasciitis, up until this recent study remained relatively unknown.
The Research
The study examined the relationship of intrinsic foot muscle volume and incidence of plantar fasciitis. The study looked at 20 runners, 10 of which had chronic bilateral plantar fasciitis of more than 2 years duration, and 10 runners who were not suffering from plantar fasciitis.
Intrinsic muscle volumes of the participants’ right foot were scanned with MRI imaging. Intrinsic foot muscle volumes were then compared between the runners with and without chronic plantar fasciitis.
The study found that there was greater rear-foot intrinsic muscle volume in healthy runners than runners with chronic plantar fasciitis. A similar finding was evident in the total intrinsic foot muscle volume, however it was not found to be statistically significant. Interestingly forefoot volume was similar in both the runners with plantar fasciitis, and those without.
These findings, despite the relatively small sample size (20), reflect my long held clinical belief, and in some manner support my frequent prescription of foot strengthening exercises for plantar fasciitis sufferers.
Two Exercises to Build Foot Intrinsic Muscle Strength and Size
Interestingly I have long held the view that intrinsic foot muscle strength loss associated with atrophy of the muscles, must be a contributory factor for the onset of plantar fasciitis. For the last several years I have routinely prescribed high load plantar fascia strengthening for the majority of runners presenting with plantar fascia pain. Click HERE>> to read more about how high load strength training can facilitate recovery from plantar fasciitis.
On occasions I have also prescribed foot ‘doming’ exercises to facilitate improved function of the foot. I prescribe these less often than the high load plantar fascia strengthening exercise. Click HERE>> to see foot doming exercises. From my knowledge there is not the evidence base to support foot doming exercises, comparative to the high load plantar fasciia strengthening exercise referenced above.
Don’t Overlook Other Contributing Factors
It’s important to note that while strength deficits and foot intrinsic muscle wastage has been validated as a factor in the onset of plantar fasciitis other injury contributory factors cannot be overlooked. These may include running technique, running shoes, deficits of hip stability, and training load errors. For more on how to address the top 5 factors that contribute to running injuries check out Amazon Running and Jogging Bestseller You CAN Run Pain Free! Click HERE>>
From my experience I have observed that overcoming plantar fasciitis can be a journey. #performbetter @pogophysio Click To TweetFrom my experience I have observed that overcoming plantar fasciitis can be a journey. It requires patience, good communication between the therapist and patient, and also the right treatment approach. Intrinsic foot muscle conditioning exercise is just one of the correct approaches required.
Any questions or comments please leave them below.
Yours in running,
Brad Beer (APAM)
Physiotherapist (APAM)
Author ‘You CAN Run Pain Free!’
Founder POGO Physio
References
Cheung, R.T et. al. Intrinsic Foot Muscle Volume in Experienced Runners With and Without Chronic Plantar Fasciitis. Journal Science & Medicine in Sport. Vol 19, (9), PP 713-715. http://dx.doi.org/10.1016/j.jsams.2015.11.004 |
