Heel pain can be caused by multiple different pathologies, the most common one being plantar fasciitis. The plantar fascia is a thick fibrous band on the underside of the foot that runs on the underside of your foot from the calcaneus (your heel bone) towards the toes. The plantar fascia, intrinsic muscles of the foot and the toe flexor muscles function together to allow the foot to be flexible enough to act as a shock absorber and to create stiffness in the foot to allow for efficient walking or running. When one of these structures in the foot doesn’t function the way it should, the biomechanics of the foot are altered which places additional stress on other tissues.
As musculoskeletal clinicians, we’ve been quick to blame flat feet or an overpronated foot as the primary cause of plantar fasciitis. Why did we pin the blame on a flat foot? It was thought that an overpronated or flat foot placed an increased tensile load on the plantar fascia eventually leading to disruption and inflammation of the collagen fibres. Plantar fasciosis is the correct term for this condition as there is disruption of the collagen fibres but there are no inflammatory cells present in the tissue. We’ve discussed this topic in another blog post which you can read by clicking here. In this post this blog post I’ll continue referring to the condition as plantar fasciitis.
Are Orthotics Effective For Plantar Fasciitis?
Orthotics have become a popular treatment option for plantar fasciitis. The theory was that if you maintain the medial arch height of the foot, tensile loads placed on the plantar fascia will be reduced. However, research done by Wearing et al. shows that orthotics are not effective for managing plantar heel pain as there is a poor correlation between low arch height and the development of plantar fasciitis.
What the authors discovered was that the best predictor for the development of plantar fasciitis was the speed at which the toes dorsiflexed during the propulsive motion.
The toe flexor muscles actively contract to help control toe dorsiflexion. Weakness of these muscles can result in the toes moving through an excessive range of motion during walking or running which increases the tensile load on the plantar fascia.
What Physical Causes Could Increase The Risk Of Plantar Fasciitis?
A study was done by Sullivan et al in 2015 where they took 202 people with plantar heel pain and compared them to 70 “normal” people without heel pain. They compared a range of potential physical causes such as:
Out of all the potential causes, the authors found three physical differences between the group with plantar heel pain and those without. They were:
These three physical factors should always be addressed in a plantar fasciitis rehabilitation program. In this post, I’ll just be discussing ways to strengthen the toe flexor and peroneal muscles. If you would like to learn more about improving ankle range of motion, it’s been covered in another blog post which you can access here.