Plantar Fasciitis, Why It Occurs and How to Avoid It
At one time or another, each of us have or will experience some kind of muscle pain and many have had the misfortune of experiencing acute pain in the foot or heel. Often, this pain is not an indication of a serious problem, sometimes it’s the symptoms of plantar fasciitis; a common condition that affects millions of people around the world.
When the fascia comes under too much tension, micro-tears can occur.
Biomechanically our feet gain the support required for normal foot mechanics from the plantar fascia. The plantar fascia itself is a dense band of connective tissue that runs along the sole of the foot. It’s role is to reduce the tension in the plantar ligaments and support the foot’s arch. This puts it under a lot of stress and plantar fasciitis occurs when the fascia comes under too much tension, especially near its origin, causing micro tears to occur. The inflammatory condition that results is known as plantar fasciitis.
Causes of exercise induced plantar fasciitis
In a 2010 study by Namik Sahin, it was found that plantar fasciitis was the most common cause of chronic pain in the lower surface of the heel. For exercise induced plantar fasciitis major causes were listed as footwear, technique and changed training conditions. A number of other studies have indicated that walking, standing or running for long periods of time especially on hard surfaces puts a person at more risk. Sahin’s findings state that it increased the risk by 3.6 times for people with a history of being on their feet for extended periods of time. In another study by Daniel L. Riddle and others in 2003, a relationship was found between plantar fasciitis and weight bearing tasks.
Physical similarities have been found in distance runners who suffer from plantar fasciitis.
Physical similarities have been found in distance runners who suffer from plantar fasciitis. According to research conducted by Michael B Pohl in 2009, it demonstrated that a lower arch index was seen in the plantar fasciitis group when compared with the control group; but Peter Brukner and Karim Khan suggest that both low arches and high arches place a person at an increased risk of developing the condition.
If these are functioning poorly, then abnormalities in midfoot supination and restrictions of ankle dorsiflexion can occur.
Another study conducted by Ben Kibler, and others, (1991) proposed a “weak link” model as an explanation of how plantar fasciitis occurs and this finding has been more recently supported by Peter Brukner, Karim QC Khan. The findings suggest that the structures of the posterior calf, ankle and foot are responsible for foot control and shock absorption during gait and if these are functioning poorly or are not tight enough, then abnormalities in midfoot supination and restrictions of ankle dorsiflexion can occur.
This can cause a pronation of the hind foot and increase the tensile loading on the plantar fascia, this was seen to increase when continuous running took place. Since this study, there has been further investigations that have provided evidence to validate this theory. In a study by Lisa Chinn and Jay Hertel, it was found that a tight achilles tendon is a possible cause and that chronic running with a bad technique contributes to the condition, while Sahin et al (2010) found that the occurrence of plantar fasciitis is tripled in people with passive ankle dorsiflexion of less than 10 degrees. Riddle et al (2003) supported this finding and highlighted it as the most important risk factor. Finally unsuitable footwear, described as old and worn with insufficient arch support, was also implicated.
In the second and final part of this series we’ll take you through how to rehabilitate after sustaining plantar fasciitis.
Emma Russo is part of our Sports Scientists and Product team. She is the product owner of our individual elite athlete product, FitYou. She graduated with a Bachelor’s degree in Exercise and Sports Science.
Burkner, P.,& Khan, K. (2012). (Burkner & Khan’s Clinical Sports Medicine) (4th ed.). Australia: McGraw Hill.
Chinn, L., & Hertel, J. (2010). Rehabilitation of ankle and Foot Injuries in Athletes. Clinical Sports Medicine (29), 157–167.
Kibler, W,B., & Goldberg, C. (1991). Functional Biomechanial Deficits in Running athletes with Plantar Fasciitis. (The American Journal of Sports Medicine. (19) 66–71.
Sashin, N., Ozturk, A., & Atici, T. (2010). Foot Mobility and Plantar Fascia Elacticity in patients with plantar Fasciitis. Acta Orthop Traumatol Ture. 385–392.