Plantar fasciitis is an overuse injury. Repetitive over-stretching of the plantar fascia under the foot leads to possible inflammation and thickening of the tendon.
The fascia can become inflamed and painful at its attachment to the heel bone or calcaneus. The condition is traditionally thought to be inflammation, however this is now believed to be incorrect due to the absence of actual inflammatory cells within the fascia.
The Plantar Fascia or plantar aponeurosis as it is also known is a broad, thick band of tissue that runs from under the heel to the front of the foot. It comprises three segments which originate from the base of the heel bone (calcaneus bone) and inserts into the forefoot.
The middle segment is most relevant to plantar fasciitis and forms the longitudinal arch of the foot providing support to the foot when standing and shock absorption when running.
Although overuse is usually thought to the cause of plantar fasciitis there are a number of factors which can increase the likelihood of developing the condition:
Overpronation is where the foot rolls in or flattens. As the foot flattens it streches the plantar fascia more than normal which increases the strain on the tissues, particularly the insertion into the underneath of the heel
High arched foot (pes cavus) causes an increased strain on the attachment of the plantar fascia to the heel. This kind of foot is often rigid and unable to absorb shock whilst running or adapt to the ground.
Wearing inappropriate foot wear such as very flat and unsupporting shoes can increase the likelihood of developing plantar fasciitis.
Overweight individuals or those who do a lot of heaving lifting at work will place increased load on the foot increasing the chances of developing heel pain.
Tight muscles are thought to be a risk factor. Tight hamstring and gluteal muscles as well as hip muscle imbalances are thought to pre-dispose people to plantar fasciitis as they affect foot biomechanics. In particular tight calf muscles and a tight plantar fascia are thought to be significant.
Preventing plantar fasciitis
Increase training gradually to reduce the chance of developing plantar fasciitis. If you are a runner you should not increase mileage by more than 10% per week.
Get a full biomechanical analysis to ensure your feet are functioning properly. You don't build a house without getting the foundations right first.
Wear correct footwear and that it is not too old. A pair of running shoes will have lost most of their cushioning after 400 miles. If you run few miles but your shoes are over 6 months old then they still may need replacing. If you have a new pair of shoes that you are not used to you may need to reduce training load or running distance until your feet have adjusted.
Stretching - continue to stretch properly especially the plantar fascia and muscles at the back of the lower leg.
Get a regular sports massage. This will help keep the muscles of the foot and lower leg in good condition. You can self massage the sole of the foot to help loosen the plantar fascia.
Apply ice to the foot after training, particularly when returning to fitness. This may help keep inflammation down before it gets bad.
Taping the foot can support the plantar fascia if you are returning to exercises after an injury.