Behind the design: How we help resolve Heel Pain - Part 1

What causes heel pain?

Pain under the heel, or plantar heel pain (PHP), is very common, accounting for up to 15% of foot-related doctor’s appointments⁽¹⁾. PHP is often caused by a condition called plantar fasciitis.

The plantar fascia is a fibrous band that helps support the arch of the foot, inserting under the heel bone. Chronic overloading may cause this structure to be injured, either from lifestyle or exercise⁽²⁾, resulting in plantar fasciitis.

There is a lot of confusing terminology around plantar fasciitis, but the research tells us that there is usually a degenerative, rather than inflammatory process going on, with the fibrous structure becoming disorganised and weakened^{(2, 3)}. Sometimes a ‘heel spur’ may be visible on x-ray, and while this may be associated with PHP, a lot of people actually have heel spurs and no symptoms at all⁽⁴⁾.

It is important to remember that a number of different conditions can cause pain under the heel (plantar heel pain, PHP).

The plantar fascia as a source of pain

Plantar Heel Pain E-Book (24)

Footwear plays a critical role in the management of Plantar Heel Pain, which is why our footwear with our Sole Hero^TM Support Footbed is designed to help address some key issues that cause pain under the heel.

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Heel Pain

Read how our features can assist with alleviating pain & symptoms:

Heel Pain

Read how our features can assist with alleviating pain & symptoms caused from heel pain:

Shock absorption

Flat feet

High arch feet

Limited Ankle Movement

More information on PHP with Simon Bartold

THE FRANKIE4 SOLE

The Role of Shock Absorption

IN MANAGING HEEL PAIN

Our occupations play a huge role in how we load our feet and many of us spend 40 hours a week standing and walking on various hard surfaces such as concrete or tiles⁽⁵⁾. People who are on their feet for much of the workday have a significantly increased risk of developing plantar fasciitis⁽⁵⁾.

One study revealed that for each increase of 10% of time spent walking there was a 52% increased risk of plantar fasciitis⁽⁶⁾, and people who spent an additional 10% of their time standing on hard surfaces (concrete, asphalt or linoleum tile on concrete) had a 30% increased risk of developing plantar fasciitis⁽⁶⁾. Nurses, teachers and hospitality workers are all at particular risk due to the nature of their work.

We may not be able to reduce how much we need to walk or stand during the day, nor can we change the hard flat surfaces we walk on. We can however alter that interface between the ground and the foot, to help provide an ‘under foot’ foundation that aims to redistribute some of the pressure away from the heel^{(7, 8)}.

We aim to do this with the combination of our support footbeds and moulded soles.

Our Sole Hero ™ Support Footbeds have a contoured heel cradle designed with the aim to distribute weight more evenly throughout the heel, compared to a flat heel surface. Through this mechanism we aim to encourage excess pressure to be directed away from the central painful area underneath the heel⁽⁹⁾.

Our Podiatrist designed dual density moulded sneaker soles are free of steel shanks and heavy materials. Like lightweight, supportive clouds under your feet - our soles were designed to help with shock absorption and cushioning under the heel.

We aim to do this with the combination of our support footbeds and moulded soles.

Our Sole Hero ™ Support Footbeds have a contoured heel cradle designed with the aim to distribute weight more evenly throughout the heel, compared to a flat heel surface. Through this mechanism we aim to encourage excess pressure to be directed away from the central painful area underneath the heel⁽⁹⁾.

Our Podiatrist designed dual density moulded sneaker soles are free of steel shanks and heavy materials. Like lightweight, supportive clouds under your feet - our soles were designed to help with shock absorption and cushioning under the heel.

THE FRANKiE4 SOLE

Supporting the arch

IN MANAGING HEEL PAIN

Studies have shown an association between PHP and faulty foot mechanics⁽⁶⁾, whether that be flat feet, rolling inwards (‘pronation’) or high-arched feet ⁽²⁾. There is also evidence that insoles or foot orthoses that provide arch support can help provide relief in PHP⁽¹⁰⁾.

Our Sole Hero^TM support footbeds are podiatrist designed. Whilst they are not a custom orthotic, they are insoles that are foot support devices with a heel cradle and arch contours that are designed with the aim to alleviate and prevent common foot symptoms associated with heel pain.

Designed to offer comfortable two-zone contoured support and cushioning.

Low-arched foot types

Researchers agree that the plantar fascia is a very important structure in supporting the arch of the foot ⁽¹¹⁾. One goal of treatment for PHP is often to reduce tensile strain on the plantar fascia by supporting the foot arch ⁽¹²⁾. Foot pronation (or ‘rolling in’) is associated with increased flexibility in the foot, and this extra flexibility may place more stress on the soft tissue structures that are required to support the arch, like the muscles, tendons and plantar fascia ⁽¹³⁾.

Our Sole Hero ™ Support Footbeds are designed to comfortably support the arch with the aim to reduce stress on these important soft tissue structures.

High-arched feet

High-arched feet are also at risk of developing PHP. These feet have reduced contact with their supporting surface and therefore higher pressures under the heel and ball of the foot. These feet are also generally less flexible than low-arched feet, and thus have reduced shock absorbing capacity ⁽⁷⁾.

The FRANKIE4 footbed aims to redistribute and reduce pressure under the high-arched foot, by 1) improving foot contact with the contoured shape, and 2) utilising soft materials and dual density properties to provide cushioning.

Limited Ankle Movement

The ankle is an important rocker or hinge-like joint, requiring about 10 degrees of flexion (called ‘dorsiflexion’) during walking. When this range of movement is restricted, meaning the ankle joint is more stiff than it should be, this causes strain on the plantar fascia ⁽¹⁴⁾. Studies have shown that restricted ankle range of movement is a risk factor for PHP ⁽⁵⁾.

By raising the wearers heel slightly higher than their forefoot, we can help ankle and foot movement for those with restricted ankle range.

For this reason, even our ‘flat styles’ are never ‘dead flat’. Most of our flat styles feature at least 10mm pitch (heel height compared to forefoot height).

Caroline McCulloch
Founder
B. Podiatry, B. Physiotherapy

Alan McCulloch
Founder
B. Podiatry, P.G.Dip in Human Movement Studies

Sara Taylor
Podiatrist
B. Podiatry (Hons)

Copywriting support also by Dr. Sheree Hurn

Dr Sheree Hurn | Podiatrist

Dr Sheree Hurn, Senior Lecturer in Podiatry at Queensland University of Technology (QUT)

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Copywriting support by Dr. Sheree Hurn

Simon Bartold

Simon Bartold is a performance footwear consultant, researcher, educator,
mentor and innovator.

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Plantar Fasciitis by Simon Bartold

Dr Sheree Hurn
- Podiatrist -

- Clinical Researcher -

Simon Bartold on LinkedIn

Simon has been an Editorial Board Member for the Journal of Science and Medicine in Sport and the Australasian Physiotherapy Journal and a journal reviewer for the Australasian Journal of Podiatric Medicine and the British Journal of Sports Medicine. He is also a member of the Advisory Committee for the Australasian Journal of Podiatric Medicine

Simon is a Fellow of the Faculty of Podiatric Medicine of the Royal College of Physicians and Surgeons (Glasg), a Fellow of the University of Melbourne at the centre for Health, Exercise and Sports Medicine (CHESM) and a Visiting Fellow at the University of Staffordshire. He has published over 30 papers in high impact peer-reviewed journals, has authored numerous book chapters and has lectured at international conferences in 41 countries.

His authored book, The Foot and Leg in Sport has been e-published to great acclaim. Research interests include the technical aspects of athletic footwear and pressure/force measurement in relation to intervention parameters and injury.

Founder of BARTOLD CLINICAL which is an online sports medicine education flatform with a focus on the lower limb and athletic footwear. It's perfect for Podiatrists, Physiotherapists, Chiropractors, Sports Doctors, Osteopaths or any professional who treats athletes who require ongoing CPD for registration compliance.

Simon Bartold

Simon Bartold is a performance footwear consultant, researcher, educator, mentor and innovator.

Simon Bartold on LinkedIn

Founder of BARTOLD CLINICAL which is an online sports medicine education platform with a focus on the lower limb and athletic footwear. It's perfect for Podiatrists, Physiotherapists, Chiropractors, Sports Doctors, Osteopaths or any professional who treats athletes who require ongoing CPD for registration compliance.

MORE INFORMATION ON PLANTAR FASCIITIS

By Simon Bartold

Many terms are used to diagnose pain under the heel, including plantar fasciitis, jogger’s heel, heel spur syndrome, plantar fascial insertitis, calcaneal enthesopathy, subcalcaneal bursitis, subcalcaneal pain, stone bruise, calcaneal periostitis, neuritis and calcaneodynia⁽¹⁸⁾. The author believes it is useful to consider plantar fasciitis as a ‘heel pain syndrome’ that may comprise one or more conditions, including the specific diagnosis of plantar fasciitis. In plantar fasciitis, the injured structure is the plantar aponeurosis at its insertion at the plantar surface of the calcaneus. The zone of insertion of tendon, ligament, or articular capsule into bone is termed the ‘enthesis’, therefore plantar fasciitis is truly an enthesopathy.

Plantar heel pain (PHP) is very common in the community. It is frequently encountered in patients who work in occupations requiring long periods of weight bearing, for example nurses, factory workers, and storemen. Extrinsic contributors to PHP may include worn or inappropriate footwear. Intrinsic factors thought to be associated with PHP include being overweight, having reduced flexibility of the plantarflexor muscles, and having structural abnormalities in the foot (for example abnormal foot pronation, pes planus, pes cavus or leg length inequality). PHP has been observed to be most common after the fifth decade of life, and this is often attributed to atrophy of the fat pad⁽¹⁹⁾. This point has been disputed by Tsai et al. ⁽²⁰⁾, who found that heel fat pad thickness was not altered in PHP patients compared to controls, however it is feasible that other mechanical properties of the heel pad, for example relative compressibility or shock absorbency, or changes to the plantar aponeurosis origin as a result of altered connective tissue characteristics with age, may contribute to the increased prevalence of PHP with age. It is important to remember that injury to the plantar fascia may occur due to high demand on normal tissue or normal demand on abnormal tissues. Local or systemic disease can cause inflammation of the plantar fascia which may weaken the fascia. Perhaps the real answer in the aetiology of PHP lies in the possibility that all the above factors may combine to create a multifactorial etiology⁽¹⁸⁾.

Biomechanics of the plantar fascia

The plantar fascia acts as a mechanical truss ⁽²¹⁾ or a platform that passively stabilises the foot ⁽²²⁾, maintaining the integrity of the medial longitudinal arch.

Even more importantly, the dynamic role of the plantar fascia, is critical to normal foot function, particularly its ability to assist in the propulsive phase of gait. This propulsive function is assisted by several extrinsic lower leg muscles, including tibialis posterior, flexor digitorum longus and flexor hallucis longus. However the plantar fascia remains a vital arch stabilising structure, acting as a shock absorber, elongating with load and storing elastic energy ⁽²³⁾.

The mechanical properties of the plantar fascia include increasing stiffness with increasing tension, and this means that the plantar fascia has an important role in resupination of the foot during the propulsive phase of gait ⁽²⁴⁾. An important function of the plantar fascia is via the “Windlass mechanism”, described by Hicks in 1954 ⁽²⁵⁾. This mechanism describes how the plantar fascia tightens when the metatarsophalangeal joints are passively extended, pulling on the calcaneal insertion of the plantar fascia and raising the medial longitudinal arch height.

The dynamic role of the plantar fascia.
File:Windlass.jpg. (2016, May 1). Physiopedia, . Retrieved March 9, 2021 from https://www.physio-pedia.com/index.php?title=File:Windlass.jpg&oldid=141323.

Pain is usually very well localised over the medial aspect of the calcaneus at the junction with the medial longitudinal arch.
Plantar Heel Pain E-Book (24)

Similarly, there can be pain over the midsubstance of the fascia
Plantar Heel Pain E-Book (24)

Patient presentation in PHP

The hallmark feature of PHP is pain in the morning on rising from rest. Severe pain is often reported on first weight bearing in the morning or after a prolonged period of rest. This pain usually improves after “warming up” within a short period of walking, but may worsen after a period of increased activity (e.g. sport or going for a long walk). The basis of this after-rest pain is thought to be due to the accumulation of inflammatory by-products which impinge on the nerve endings when compressed during weight bearing ⁽²⁴⁾.

Pain will often be localised over the medial aspect of the fascial origin, and this assists greatly in making the diagnosis. There may be more diffuse areas of pain in the mid-substance of the fascia, however this is less common. Sometimes patients will present with diffuse tenderness up the medial or lateral aspect of the calcaneus, which is typical of a more severe inflammatory process, and in these cases care must be taken to rule out a calcaneal stress fracture or other more serious pathology (see box of differential diagnoses below).

Nodular changes to the fascia may be found in PHP, and this represents fascial fibromata formed as the result of repeated fascial injury which has healed with scarring. If large these fibromas can be very uncomfortable during weight-bearing and may require offloading with customised insoles or foot orthoses. Sometimes pain can be reproduced with passive talocrural joint dorsiflexion. Stretching of a tight posterior muscle group is essential in the rehabilitation of plantar fasciitis, and this is described below.

Pain is usually very well localised over the medial aspect of the calcaneus at the junction with the medial longitudinal arch. Plantar Heel Pain E-Book (24)

Similarly, there can be pain over the midsubstance of the fascia. Plantar Heel Pain E-Book (24)

Differential Diagnosis

Making an accurate diagnosis in cases of PHP is extremely important. Some serious systemic diseases and tumours can present as simple overuse injuries such as plantar fasciitis. Therefore, it is essential to take a thorough history and listen to the patient for clues that may indicate a more sinister condition.

Box 1 Diagnoses that may result in heel pain (adapted from Bartold et al. 2004) (24):

Complete rupture of the plantar fascia
Subcalcaneal bursitis
Medial calcaneal nerve entrapment
Tarsal tunnel syndrome
Ruptured fat pad
Sever’s disease
Calcaneal stress fracture

Seronegative arthropathy (e.g. ankylosing spondylitis)
Reiter’s Syndrome
Psoriatic arthritis
Diffuse connective tissue disease (e.g. Rheumatoid arthritis, Systemic Lupus Erythematosus)
Tumour

Investigations

Plain film radiographs are still used routinely in the medical community to screen for the so called “heel spurs” often associated with plantar fasciitis. A highly significant association has been reported between plantar fasciitis and calcaneal spurs ⁽²⁶⁾, however calcaneal spurs are also found in many asymptomatic feet ⁽⁴⁾. Therefore, the main role of quality plain films in relation to PHP, is to exclude a bone pathology such as calcaneal stress fracture.

A more useful modality for confirming a diagnosis of PHP is diagnostic ultrasound. Ultrasonography is an excellent diagnostic imaging modality for evaluating PHP, because it is non-invasive and high resolution, and provides objective evidence of the presence of inflammation ⁽²⁰⁾. The thickness of the plantar fascia may be observed to be increased in PHP, with Kamel and Kotob ⁽²⁷⁾ reporting a mean thickness of 5.8 +/- 2.6 mm in a symptomatic cohort of subjects as compared to 2.3 +/- 1.1 mm in the control group. However, magnetic resonance imaging (MRI) is the only modality that can pinpoint the diagnosis of plantar fasciitis ⁽²⁸⁾. Because the plantar fascia is composed primarily of collagen, all pulse sequences of MRI will demonstrate hypointensity in normal fascia. However, in PHP when this fibrous network is interrupted, extra cellular inflammatory by-products increase the MRI signal.

Treatment

Short-term management of PHP is similar to most overuse injuries, i.e. activity modification or rest, ice, compression and medication to reduce pain and inflammation⁽²⁴⁾.

Ongoing management requires a staged and sequential approach, and may include any of the following, as deemed appropriate by the treating health professional:

Stretching - Specific stretching should be to the gastrocnemius/soleus complex, the hamstrings and the plantar fascia itself. Traditionally, stretching of the plantar fascia has been achieved by rolling the foot over an ice-filled bottle.

Stretching the gastrocnemius. The heel remains on the ground with the knee extended. The foot must be at “12 O’clock”. i.e. pointing straight ahead to achieve the correct stretch. Plantar Heel Pain E-Book (24)

A simple technique for stretching the plantar fascia. Grasp the hallux and dorsiflex until the fascia becomes prominent to palpation. Maintain the stretch for a count of thirty and repeat often.
Plantar Heel Pain E-Book (24)

Activity modification or rest- Total rest may be required in some cases of recalcitrant PHP. Usually however, cross training is allowed, with activity substitution of bike riding, swimming, or stair climber substituted for walking or running.

Taping – An effective taping technique is described by Bartold et al. (2004) in the Journal of Bodywork and Movement Therapies ⁽²⁴⁾.

Foot orthoses - The use of orthoses in the treatment of PHP is based on the principle of reducing tissue stress. Orthoses come in many forms, and may include cushioned heel pads, compressive heel cuffs, prefabricated or custom-made orthoses. The rationale for the treatment of PHP with foot orthoses has been based on the theoretical association between excessive foot pronation and the development of PHP. Subtalar joint pronation everts the calcaneus and lengthens the plantar fascia, therefore increasing tension in the fascia ⁽²¹⁾.

Secondly, subtalar joint pronation increases mobility of the foot and therefore increases the tissue stress due to increased foot mobility ⁽¹³⁾. However, midfoot deformation may be a more important factor in increasing plantar fascial loading, and therefore orthoses supporting the medial longitudinal arch (rather than stabilising the subtalar joint) may be more effective. This is supported by anecdotal evidence that shoe inserts providing total contact to the plantar surface of the foot may provide better outcomes in relation to PHP than more rigid, custom made orthoses. Kogler et al. ⁽¹²⁾ reported that reducing tension in the plantar aponeurosis is an important treatment objective in the orthotic management of plantar fasciitis.

These authors found via a cadaveric study that foot orthoses designed to provide total contact to the plantar surface of the foot significantly decreased the strain in the plantar fascia. It seems likely there is a paradigm shift away from controlling specific joint motion in the foot, to supporting the soft tissues in the plantar surfaces of the foot.

Chronic cases of PHP that have been unresponsive to the treatments above, may require one or more of the following treatment approaches:

Night splints - A tension posterior night splint may be used in recalcitrant cases of PHP. Because normal tone of the gastrocnemius and soleus allow the foot to assume a plantarflexed position during sleep, the posterior group and plantar fascia become relatively shortened and non-functional, and it is this position that is thought to account for the first step pain in the morning ⁽²⁹⁾.

The night splint works on the principle that a connective tissue such as the plantar fascia will respond to stress-relaxation, that is, the decrease in stress on a material over time, once that tissue has deformed to a constant length under loaded conditions ⁽³⁰⁾.

Short-leg walking cast

Corticosteroid infiltration

Extracorporeal shock wave therapy

Surgery

Summary

PHP remains a troubling condition for patients and health professionals alike. Most researchers and clinicians agree that patients with insertional plantar fascial pain can achieve good results without resorting to surgery. There is no agreement regarding a ‘gold standard’ treatment for PHP, however, it appears that early, aggressive, non-surgical treatment within 12 months of the onset of symptoms offers the best chance of a positive outcome ⁽³¹⁾.

The longer that non-surgical management has been unsuccessful, the lower the chance becomes of a good prognosis, however, research indicates that conservative management is preferable to surgical intervention, and the indications for surgery in PHP are limited. Education and encouragement are key components of successful management of PHP, since resolution of symptoms can often be very slow over the course of several months.

By Simon Bartold

If you are a Podiatrist, Physiotherapist, Chiropractor or Sports Doctor who requires ongoing CPD for compliance, have enjoyed this blog post, and want to learn more, Simon Bartold's Bartold Clinical is an online sports medicine education platform with a focus on the lower limb.

Disclaimer: The contributors to this article make every effort to make sure the information provided is accurate. All content is created for informational purposes only. The information regarding our products is not intended to replace professional or medical advice relevant to your circumstances. Discontinue use if you experience discomfort and seek advice from your health care professional.

This article contains copyrighted material. Reproduction and distribution of this article without written permission from FRANKIE4 footwear is prohibited. ©2021 FRANKIE4 footwear. All rights reserved.

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Read below the feedback from our customers who have experienced heel pain relief with FRANKIE4.

I have history of plantar fasciitis and a wide foot.
But this shoe caters to both, and has alleviated any foot pain.
I have worn mine to walk around the city on a staycation and still felt so much comfort!
Happy feet!

MEGAN J.

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I've had plantar fasciitis for 18 months and I'm a beauty therapist
so on my feet a lot of the day. I got myself some FRANKiE4's for the summer
and they have been a heel saver, no more pain!!! I'm just about to purchase
some black ones for the winter love love love these shoes. Goodbye heel pain.

AMY R.

Verified Buyer

Honestly like walking on clouds. The most comfy shoes I have worn.
No blisters, arch pain, heel pain or pain on the sides of my feet.
Have recommended to so many of my nursing friends.
I will definitely be buying another pair. Honestly like walking on clouds. Goodbye heel pain.

CRISSY C.

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References

1. Buchbinder R. Plantar Fasciitis. The New England Journal of Medicine. 2004; 350:2159-2166.
2. Schwartz EN, Su J. Plantar fasciitis: a concise review. The Permanente Journal. 2014; 18:e105-e107.
3. Lemont H, Ammirati K, Usen N. Plantar fasciitis: a degenerative process without inflammation. Journal of the American Podiatric Association. 2003; 93:234-237.
4. Kirkpatrick J, Yassaie O, Mirjalili SA. The plantar calcaneal spur: a review of anatomy, histology, etiology and key associations. Journal of Anatomy. 2017; 230:743-751.
5. Riddle DL, Pulisic M, Pidcoe P, Johnson RE. Risk Factors for Plantar Fasciitis: A Matched Case-Control Study. Journal of Bone and Joint Surgery. American Volume. 2003; 85:872-877.
6. Werner R, Gell N, Hartigan A, Wiggerman N, Keyserling W. Risk Factors for Plantar Fasciitis Among Assembly Plant Workers. PM&R. 2010; 2:110-116.
7. Najafi B, Wrobel JS, Burns J. Mechanism of orthotic therapy for the painful cavus foot deformity. Journal of Foot and Ankle Research. 2014; 7:2.
8. Bonanno DR, Landorf KB, Menz HB. Pressure-relieving properties of various shoe inserts in older people with plantar heel pain. Gait & Posture. 2010; 33:385-389.
9. Telfer S, Woodburn J, Turner DE. Measurement of functional heel pad behaviour in-shoe during gait using orthotic embedded ultrasonography. Gait & Posture. 2013; 39:328-332.
10. Whittaker GA, Munteanu SE, Menz HB, Tan JM, Rabusin CL, Landorf KB. Foot orthoses for plantar heel pain: a systematic review and meta-analysis. British Journal of Sports Medicine. 2018; 52:322-328.
11. Wearing SC, Smeathers JE, Urry SR, Hennig EM, Hills AP. The Pathomechanics of Plantar Fasciitis. Sports Medicine. 2006; 36:585-611.
12. Kogler GF, Solomonidis SE, Paul JP. Biomechanics of longitudinal arch support mechanisms in foot orthoses and their effect on plantar aponeurosis strain. Clinical Biomechanics (Bristol). 1996; 11:243-252.
13. Cornwall MW, McPoil TG. Plantar fasciitis: etiology and treatment. The Journal of Orthopaedic and Sports Physical Therapy. 1999; 29:756-760.
14. Beeson P. Plantar fasciopathy: Revisiting the risk factors. Foot and Ankle Surgery. 2014; 20:160-165.
15. Rabusin CL, Menz HB, McClelland JA, Tan JM, Whittaker GA, Evans AM et al. Effects of heel lifts on lower limb biomechanics and muscle function: A systematic review. Gait & Posture. 2019; 69:224-234.
16. Johanson MA, Cooksey A, Hillier C, Kobbeman H, Stambaugh A. Heel lifts and the stance phase of gait in subjects with limited ankle dorsiflexion. Journal of Athletic Training. 2006; 41:159-165.
17. Kogler GF, Veer FB, Verhulst SJ, Solomonidis SE, Paul JP. The Effect of Heel Elevation on Strain Within the Plantar Aponeurosis: In Vitro Study. Foot & Ankle International. 2001; 22:433-439.
18. DeMaio M, Paine R, Mangine RE, Drez D. Plantar fasciitis. Orthopedics. 1993; 16:1153-1163.
19. Sherreff MJ. Geriatric foot disorders: how to avoid under treating them. Geriatrics. 1987; 42:69-80.
20. Tsai W-C, Chiu M-F, Wang C-L, Tang F-T, Wong M-K. Ultrasound evaluation of plantar fasciitis. Scandinavian Journal of Rheumatology. 2000; 29:255-259.
21. Kwong P, Kay D, Voner RT, White MW. Plantar fasciitis. Mechanics and pathomechanics of treatment. Clinics in Sports Medicine. 1988; 7:119-126.
22. Cooper P. Current concepts on the management of heel pain. Medscape Orthopaedics & Sports Medicine. 1997; 1:1-10.
23. Wright D, Rennels D. A study of the elastic properties of plantar fascia. The Journal of Bone and Joint Surgery. American Volume. 1964; 46:482-492.
24. Bartold SJ. Plantar heel pain syndrome: overview and management. The plantar fascia as a source of pain - biomechanics, presentation and treatment. Journal of Bodywork and Movement Therapies. 2004; 8:214.
25. Hicks J. The mechanics of the foot: II. The plantar aponeurosis and the arch. Journal of Anatomy. 1954; 88:25.
26. Johal K, Milner S. Plantar fasciitis and the calcaneal spur: fact or fiction? Foot and Ankle Surgery. 2012; 18:39-41.
27. Kamel M, Kotob H. High frequency ultrasonographic findings in plantar fasciitis and assessment of local steroid injection. The Journal of Rheumatology. 2000; 27:2139-2141.
28. DiMarcangelo M, Yu TC. Diagnostic imaging of heel pain and plantar fasciitis. Clinics in Podiatric Medicine and Surgery. 1997; 14:281-301.
29. Sobel E, Levitz SJ, Caselli MA. Orthoses in the treatment of rearfoot problems. Journal of the American Podiatric Medical Association. 1999; 89:220-233.
30. Carlstedt C, Nordin M. Biomechanics of Tendons and Ligaments. In: Nordin M, Frankel V (editors). Basic Biomechanics of the Musculoskeletal System (2nd Ed). Philadelphia: Lea & Febiger; 1989.
31. Martin RL, Irrgang JJ, Conti SF. Outcome study of subjects with insertional plantar fasciitis. Foot & Ankle International. 1998; 19:803-811.

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