Use of MRI for volume estimation of tibialis posterior and plantar intrinsic foot muscles in healthy and chronic plantar fasciitis limbs. Chang R, Kent-Braun JA, Hamill J. Clin Biomech (Bristol, Avon). 2012 Jun;27(5):500-5.
Due to complexity of the plantar intrinsic foot muscles, little is known about their muscle architecture in vivo. Chronic plantar fasciitis may be accompanied by muscle atrophy of plantar intrinsic foot muscles and tibialis posterior compromising the dynamic support of the foot prolonging the injury. Magnetic resonance images of the foot may be digitized to quantify muscle architecture. The first purpose of this study was to estimate in vivo the volume and distribution of healthy plantar intrinsic foot muscles. The second purpose was to determine whether chronic plantar fasciitis is accompanied by atrophy of plantar intrinsic foot muscles and tibialis posterior.
Magnetic resonance images were taken bilaterally in eight subjects with unilateral plantar fasciitis. Muscle perimeters were digitally outlined and muscle signal intensity thresholds were determined for each image for volume computation.
The mean volume of contractile tissue in healthy plantar intrinsic foot muscles was 113.3 cm(3). Forefoot volumes of plantar fasciitis plantar intrinsic foot muscles were 5.2% smaller than healthy feet (P=0.03, ES=0.26), but rearfoot (P=0.26, ES=0.08) and total foot volumes (P=0.07) were similar. No differences were observed in tibialis posterior size.
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. These results suggest that magnetic resonance imaging measures may be useful in understanding the etiology and rehabilitation of chronic plantar fasciitis.
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. Still, it’s a very interesting study. The authors pointing 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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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.
2 thoughts on “Plantar Fasciitis Associated with Foot Muscle Atrophy”
My both feet muscles shrinks and feels stiffness. I have heels spur too. Your advice pls.
Male 68 age
I would think the best thing for foot muscle atrophy is electric muscle stimulation. With a machine you can program like this, using rubber carbon electrodes, either strapping one to the bottom of each foot while you sit, or standing on a pair of electrodes each (one under the ball and heel of each foot).
Calf stretches should help, as well as calf muscle strengthening, and strengthening of all the legs and hips. I think I explain why best in this blog. Spinal Flow Yoga, plus calf stretching and foot EMS is what I would do if I didn’t have access to a gym. Unfortunately plantar fasciitis isn’t and easy fix, but on the bright side, all the exercises I recommend are good for your entire body. No matter what, I would not not my doctor give me a cortisone shot!
Heel spurs usually aren’t a problem. Research suggests you probably had them long before the pain started and didn’t even know it.