What is it?
Plantar fasciitis is the most common cause of pain under the heel bone. It is classed as a degenerative condition due to commonly found changes such as deterioration of collagen fibres and micro tears of plantar fascia tissue.
The plantar fascia is a thick band of connective tissue which runs from the heel bone along the underside of the foot and attaches to the toes. This explains why it plays an important part in maintaining the arch of the foot. The plantar fascia is also involved in absorbing forces during movement and contributes to propelling us forward during walking and running. Research estimates that plantar fasciitis accounts for up to 10% of running related injuries.
How is it caused?
It is not always clear why people develop plantar fasciitis as it effects both sedentary and active populations but there is good evidence highlighting risk factors for developing this condition. Increased weight bearing activity can overload the plantar fascia tissue and trigger pain. This could be increasing running volume or simply switching to a job with more standing required. Being overweight leads to changes in structure of the plantar fascia and predisposes to developing plantar fasciitis. Having a reduced arch of the foot or an excessive arch can also predispose to plantar fasciitis as it alters force dissipation through the plantar fascia. Excessively tight calf and soleus muscles can also affect plantar fascia function.
How to treat it?
Educating people about this condition is essential to successful treatment. Understanding this takes months rather than weeks to show real improvement is important and advice about activity modification is central to good outcomes. Reducing activities that flare up this heel pain for a short period of time can help pain levels settle. Gradually building up activity levels again is also essential rather than introducing large spikes of activity once there are initial signs of improvement. Footwear advice is important and cushioned supportive shoes with a gel heel insert can help reduce impact on the plantar fascia insertion and also offload the connective tissue slightly by raising the heel.
In terms of active intervention the traditional approach has been stretching the calf and soleus muscles as well as isolated stretching of the plantar fascia. More recent evidence recommends high load strength training of the calf, achilles tendon and plantar fascia. This concept is borrowed from rehabilitating tendons and the early research is promising. The unique aspect of the strength training is that it puts high amounts of stress through the plantar fascia by using the Windlass mechanism. This involves propping the big toe up during a heel raise, ultimately increasing the stress through the plantar fascia by more than 400% compared to stretching.
A “best practice” rehabilitation plan should draw on the more traditional approach but also incorporate the newer strength based approach.
A typical plan is outlined below:
1) Reduce weight bearing activities for a two weeks period to allow symptoms to settle.
2) For any weight bearing activities use cushioned trainers with a gel heel insert.
3) Perform standing calf stretches of one minute duration x 5 repetitions twice daily.
4) Perform seated plantar fascia stretches for 10 seconds duration x 10 repetitions twice daily.
5) Perform single leg heel raises off a step with a towel elevating the big toe (to optimise the Windlass mechanism). Aim for 12 repetitions and if this is being achieved add external weight through a loaded backpack so that the set is very difficult to complete. Perform this every second day. Over time your physiotherapist will progress this exercise so that repetitions decrease but sets and weight increases.
Summary
This can be a stubborn condition and difficult to get on top of but the advice and exercise approach outlined above is an excellent start. As with every injury an individualised approach is key and speaking to a chartered physiotherapist will help outline specific contributing factors to the problem and plan a tailored rehabilitation programme in keeping with your goals.
Key References
DiGiovanni B et al (2003) “Tissue-specific plantar fascia-stretching exercise enhances outcomes in patients with chronic heel pain. A prospective, randomized study” The Journal of Bone & Joint Surgery (85) 1270–1277 https://insights.ovid.com/pubmed?pmid=12851352
Rathleef, M et al (2015) “High-load strength training improves outcome in patients with plantar fasciitis: A randomized controlled trial with 12-month follow-up: HL strength training and plantar fasciitis” Scandinavian Journal of Medicine and Science in Sports 25 (3) 292 – 300 https://tinyurl.com/yym926q7
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