Plantar fasciitis is a condition that affects roughly 10% of the population. Plantar fasciitis isn’t always a standalone problem; therefore, a comprehensive foot evaluation is beneficial to ensure that you have a global approach identifying the root cause of your pain. Sometimes, plantar fasciitis is the result of a different problem. There are specific risk factors for plantar fasciitis and understanding the risk factors are, can help us create a proactive plan to help decrease risk for plantar fascia heel pain. We have looked through the literature and compiled a list of the most common causes of plantar fasciitis.
1. Weight / BMI
If a person has a BMI greater than 25, there is a statistical 5x greater chance of developing plantar fascia pain.
2. Flat Feet / High Arches
- Flat feet: often incorrectly labeled as overpronation, is routinely blamed for plantar fascia symptoms. The role of pronation is to unlock the foot and prepare it to absorb impact with the ground. As the medial longitudinal arch collapses (fallen arch), the plantar fascia is placed on continuous load/tension, thus potentially creating failure over time.
- High arches: this makes the foot rigid, while approximating or shortening the distance between the ball of the foot and the heel. A rigid foot lacks the ability to disperse impact forces efficiently, therefore there is more high frequency vibration transmitted to the passive tissues like the plantar fascia and can result in injury over time.
3. Decreased Range of Motion of Ankle
There is a 25x greater risk of developing plantar fascia pain if you have less than 0 degrees of ankle Dorsiflexion range of motion. This can happen either because of a tight calf, or because of a joint problem restricting motion.
4. Decreased Big Toe Mobility (Dorsiflexion)
The great toe is the steering wheel of the foot. The backwards bend of the big toe tenses the plantar fascia. This allows the plantar fascia to act as a “trust” for the arch. It allows the foot to be rigid for push off and protects the mid foot from collapse. This mechanism is called the windlass mechanism of the foot.
5. Foot Intrinsic Weakness
The foot intrinsic muscles are the primary dynamic stabilizer of the foot. They control the foot’s ability to adapt to the surface we stand on for balance, coordination, and dynamic activity. These muscles lock and unlock the foot to be both stable and mobile, which is a tall task for such a small group of muscles. Research suggests that if the foot intrinsics are under expressed or weak (inhibited), they will have a 40% less effective/efficient “core”. The implications of poor foot intrinsics function are great, and are a point of focus for us… but it isn’t just about strength, it is about endurance, reaction time, and efficiency of integration with other muscle groups.
6. Fat Pad Atrophy
Deterioration of the fat pad under the heel causes an increase in high frequency vibration to be transferred to the plantar fascia causing it to thicken. This thickening causes plantar fascia pain.
Statistics indicate that plantar fascia pain occurs most often in the fifth decade of life. This would correlate nicely with the concept that it is more often a degenerative problem than inflammation.
8. Overtraining / Inadequate Training
This is an often overlooked risk factor because it is hard to objectively determine how much work is over training, and it changes from person to person. Overtraining also is something that would make each and every risk factor significantly worse.
9. Poor Fitting Shoes
Poor or ill fitted shoes, particularly ones that prevent splaying of the forefoot, or provide so much structure it interferes with normal foot function, can interfere with expression of foot intrinsics. Research would suggest that roughly over 70% of women, and 50% of men are routinely wearing ill fitted shoes
Females have a 6x greater rate to develop fat pad atrophy than males, which is oftentimes a contributing factor to plantar fascia pain.