Plantar fasciitis is one of the most common causes of heel pain. It is defined as inflammation of the plantar fascia due to repetitive micro-trauma from excessive traction and/or loading forces. Plantar fasciitis is also typically not just an acute inflammatory condition. It is now recognised as more of a chronic degenerative condition and as such could be renamed plantar fasciopathy. Your plantar fascia is on the underside of your foot and is shaped like bow string. It is a thick aponeurosis (a strong fibrous tissue) that connects the heel to the toes. The orientation of the plantar fascia helps maintain the medial longitudinal arch of the foot when walking. It also helps to maintain the appropriate timing of pronation and supination. Pronation is the normal movement that occurs at your foot whenever you walk or run. As you take a step, your heel strikes the ground first, then your foot naturally ‘rolls over’ from the outside portion of your foot to the inside portion of your foot. Sometimes people over pronate, others under-pronate (also known as excess supination).
SymptomsPlantar fasciitis typically causes a stabbing like pain in the bottom of your foot near the heel. The pain is usually at its worst with the first few steps after rising from sleep. It can also be triggered by long periods of standing or when you get up after sitting for lengthy periods. The pain is usually worse after exercise, not during it.
CausesYour plantar fascia supports the arch of your foot and absorbs shock when you walk and run. If tension and stress on this bowstring shaped fascia becomes too great, small tears can occur. Repeated stretching and tearing can irritate or inflame the fascia. Often, the specific cause of plantar fasciitis can remain unclear. Most commonly, individuals report plantar fasciitis pain after a period of increased or unaccustomed activity. Especially after a period of inactivity. It can happen after completing a more vigorous activity than you are accustomed to or increasing your running/walking mileage. It can simply be increasing the time spent on your feet every day at work. Wearing shoes with soft soles and poor arch support can also be a factor.
Risk factorsEven though plantar fasciitis can develop without a known cause you are at higher risk if you fit into the following categories.
- Age– active people between 40-60 are most likely to suffer.
- Obesity– excess weight puts a greater load on the soft tissues in the foot.
- Exercise– such as running, aerobics, dancing all place a lot of load through the feet.
- Occupation- your job involves lots of time standing/walking eg teacher, physiotherapist, factory worker.
- Tight calf muscles and achilles tendon tightness predispose you to plantar fasciitis.
- Structural foot problems– such as high arches or flat feet (pronated feet) or limited ankle range of motion. Overpronation can lead to a flattening of the medial longitudinal arch (MLA) causing the plantar fascia to elongate. This increases tensile forces within the foot causing micro-tears. So an over-pronated foot has too much mobility. An underpronated foot is too rigid with limited ability to absorb shocks. The foot is unable to dissipate forces so the fascia takes the brunt of the load.
DiagnosisPlantar fasciitis is diagnosed via your history and physical examination. Imaging is usually not necessary. Your GP may suggest an X-ray or MRI to rule out other factors such as a stress fracture. Especially if you are not responding to conservative treatment. Imaging will sometimes reveal a bone spur on the heel. This can be due to excessive tension from the plantar fascia causing periosteal lifting of the bone. That is, the body is responding to the strain by laying down extra bone.This is often a symptom of the plantar fasciitis and not a cause. It is worth noting that many people who have bone spurs on their heels have no heel pain.
TreatmentThe good news is that the vast majority of those diagnosed with plantar fasciitis will recover in 6-12 months with conservative treatment such as rest, icing, anti-inflammatories, exercises and stretching as described below.
- Plantar fascia-specific self-stretches and calf stretches
- Limited ankle range of motion and big toe mobility can also be risk factors for developing plantar fasciitis. If you do not have big toe extension or have a stiff ankle, you will not be able to roll through your foot and your toe as you walk. The following videos show how to self mobilise your ankle and big toe mobility exercises.
- Alternatively try a purpose designed pad or orthosis to help add length to the fascia and foot. Fasciitis fighter is an example.
- Foot intrinsic exercises are also useful in maintaining your foot mobility. These exercises work on the many small muscles in the foot and have been covered in a previous post that you can access here Foot Fitness in 5 minutes.
- Improve your proximal muscle strength. Muscle weakness higher up the leg in the glutes, quadriceps or core can contribute to dysfunction at the foot. These proximal muscles assist when your heel first hits the floor—they are necessary for shock absorption. If these muscles are weak, there may be an excessive transmission of shock to the structures of the feet rather than a dissipation of these forces throughout the entire limb. Exercises such as clams, side-planks, glutes with a roller are great ways to improve your trunk or proximal strength.
- High-load strength training – this exercise may stimulate an increase in collagen synthesis as well as encourage the fascia to tolerate load. This exercise can also increase ankle dorsiflexion range and intrinsic foot strength. It follows the concept that soft tissue heals according to the demands by which it is mechanically stressed. This is quite an advanced exercise.