Key Points:
Overuse Injury: Plantar fasciitis is primarily an overuse injury, stressing the importance of managing the cumulative stress on the plantar fascia.
Total Plantar Fascia Stress: A critical equation to remember is that plantar fasciitis occurs when the total stress (cumulative stress x intensity of stress) on the plantar fascia exceeds its resilience.
Cumulative Stress Factors: Time spent on your feet and the number of steps you take significantly contribute to the cumulative stress.
Intensity of Stress Factors: The intensity of the stress placed on your feet, influenced by activities like running, your body weight, shoe fit, the surface you're on, and your biomechanics, plays a key role.
Categories of Causes: The causes of plantar fasciitis can be broken down into two main causes:
- Lifestyle Causes
- Biomechanical Causes
Why It's Crucial to Understand the Cause of Plantar Fasciitis
Plantar Fasciitis, a common source of heel pain, often intrudes into the lives of many, causing discomfort and impacting daily activities. Although the ailment is widespread, understanding its root causes can pave the way for effective treatment and prevention.
As a physical therapist, patients who get better are the ones who understand their injury well, including what is causing it. This is why sharing the root causes of plantar fasciitis with you is important.
My goal is to provide you with research-backed information on the factors that can play a role in the development of plantar fasciitis.
These are the same causes I try to identify when patients with plantar fasciitis come into my office.
Benefits of knowing the root cause of your plantar fasciitis
Tailored Treatment: Imagine trying to fix a car without knowing what's broken. Sounds tricky, right? The same goes for our feet. By identifying the root cause, we can tailor treatments that target the specific issue, making recovery more efficient.
Save Time and Money: Random treatments are like throwing spaghetti at the wall and seeing what sticks. By knowing the cause, you can invest in therapies that work, saving time and money.
Empowerment: Knowledge is power, my friends! Understanding the cause equips you with the tools and knowledge to take control of your recovery journey.
Holistic Health: Our bodies are interconnected. By addressing the root cause of plantar fasciitis, we might also improve other aspects of our health. It's a win-win!
Prevention is Better Than Cure: Once we know the cause, we can take steps to prevent future flare-ups. It's like having a roadmap to a pain-free future.
While it might be tempting to jump straight into treatments, taking a moment to understand the 'why' behind your pain can make all the difference.
Let's get into it…
Causes of Plantar Fasciitis Simplified
When boiled down to its pure form, plantar fasciitis is an overuse injury. We must figure out how to decrease the total stress through the plantar fascia.
This equation sums it up.
Total Plantar Fascia Stress
=
Cumulative Stress
X
Intensity of Stress
- Cumulative Stress - Stress on the plantar fascia accumulates over time. Factors that fall into this category include time on your feet and the number of steps you take.
- Intensity of Stress - The intensity of the stress you put on your feet is the other factor to consider. For example, running will put more stress on your plantar fascia than walking. Factors that affect this include your body weight, shoe fit, the surface under your feet, and biomechanics such as foot core weakness, tightness in calves, and hip weakness.
This brings us to this conclusion...
Plantar fasciitis happens when the total stress on the plantar fascia is greater than the stress it can handle.
Plantar Fasciitis
=
Total Plantar Fascia Stress > Plantar Fascia Resilience
If the total stress on your plantar fascia is higher than it can handle, it becomes irritated and painful, leading to plantar fasciitis.
This means that you can prevent or cure your plantar fasciitis. We need to change the variables to either allow your plantar fascia to handle more stress or decrease the stress on it.
Breaking Down the Causes
The causes of plantar fasciitis can be broken down into two categories. Lifestyle causes and biomechanical causes. Breaking the causes into two categories keeps things simple.
Think of lifestyle causes as things that you can change by adjusting what you do during the day and biomechanical causes as things that can be changed with exercise (can you tell I'm a physical therapist?).
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Lifestyle Causes
Like I said, lifestyle causes of plantar fasciitis are factors you can adjust throughout your day. You will notice some of the things in this category may be unavoidable, and this is fine because you will more than likely find you will have multiple causes. Plantar fasciitis is often not caused by just one thing but a cumulative of factors.
Standing on Your Feet All-Day
If your job keeps you on your feet all day, you may unknowingly be rolling out the red carpet for plantar fasciitis. Prolonged weight-bearing stresses the plantar fascia, potentially leading to those micro-tears and the onset of plantar fasciitis.
Unfortunately, your job is your job. Chances are you can not change what you are required to do, so you won’t be able to change this. However, if you can figure out how to get off your feet and give your plantar fasciitis a break, it can help relieve the cumulative stress put on your plantar fascia. [1]
Standing on Hard Surfaces
The type of surface you stand or walk on is more than just a matter of comfort. A hard, unyielding surface like concrete can escalate the stress on your plantar fascia, nudging it to its breaking point.
Once again, this is one of those factors you may not be able to avoid. Keep it in the back of your mind.
That being said, investing in supportive footwear or cushioned mats can act as a buffer between your feet and the ground, lessening the impact through your feet. [2]
Increased Activity levels too quickly
While your plantar fascia is not a muscle, it adapts to stresses like one. It needs time to adapt to the stress you put on it. If you suddenly increase your activity level without giving it time to adjust, you're setting the stage for plantar fasciitis.
I see this a lot in the summertime when people start to get outside and go for walks and again around the new year when everyone hits the gym hard.
I always encourage the 10% rule, where you increase the distance or intensity of your exercise by no more than 10% of that previously. It’s important to have a plan and to stick to it.
Hint hint: This slow progressive loading is also a key component of recovery, but that is for a different post.
Poor Fitting Shoes
This comprehensive study found that footwear plays a significant role in the development and severity of plantar fasciitis. The study found that a staggering 83.2% of participants diagnosed with plantar fasciitis were wearing ‘inappropriate shoes.’
These ‘inappropriate shoes’ were characterized by minimal heel height, thin soles, and hard insoles without any built-in arch support.
This aligns with the understanding that inadequate footwear can put extra strain on the plantar fascia, leading to overuse and pain.
The study strongly suggests that a simple change in shoe selection—opting for shoes with a moderate heel height between 0.5 and 4 cm, thick soles, and cushioned or arched insoles - could potentially alleviate symptoms and prevent further discomfort and disability.
Biomechanical Causes
Now for the other category, biomechanical causes of plantar fasciitis. These causes can be changed by targeted exercise. And with some commitment, this category can be the most beneficial to change.
Tight Calves
To understand how tight calves can cause plantar fasciitis, you need to understand the anatomy. Tight calf muscles can place extra stress on the plantar fascia, leading to its excessive stretching.
Calf Anatomy
Over time, this extra stress can cause small tears in the plantar fascia, resulting in plantar fasciitis.
In a study, patients suffering from plantar fasciitis were prescribed physical therapist-directed calf stretching exercises, a Strassburg Sock or night splint, and silicone heel insoles as necessary.
Through these interventions, a decrease in calf tightness was observed, alongside a reduction in reported pain scores for morning and weekly worst pain.
This implies that calf stretching, which alleviated calf tightness, significantly reduced heel pain associated with plantar fasciitis.
High BMI
This study found a positive link between a high BMI and plantar fasciitis. The researchers compared signs of plantar fascia irritation in individuals with high BMIs vs. those with non-high BMIs. They found a correlation between having a higher BMI and signs of plantar fasciitis.
This study's findings make sense when you think about it from an anatomical approach. If you weigh more, your plantar fascia will be under more stress. More stress through the plantar fascia is going to overload it to the point it becomes plantar fasciitis.
You can use the BMI calculator below.
BMI Calculator
Your BMI is:
A BMI of 30 or above is categorized as obesity. If your BMI falls in these ranges, it can contribute to your plantar fasciitis.
**Remember, while BMI is a useful initial screening tool, it's not a direct measure of body fat, and it should just be one aspect to consider regarding your health and potential causes of plantar fasciitis.**
Flat Feet
Pronation is a natural foot movement that occurs during foot landing while walking or running. It helps us absorb our body weight. However, when this movement is excessive (flat feet or hyperpronation), it can become a problem.
This study found that individuals with flat feet had increased plantar pressure through the foot.
Flat feet often result in a more flexible, lower-arched foot, increasing the tension applied to the plantar fascia during the weight acceptance phase of gait.
Flat feet are further exacerbated by weakness in the foot core, the hips, or the intrinsic foot muscles. These muscles play a crucial role in controlling pronation and reducing tension on the plantar fascia.
This is why targeting these muscles when performing exercises for your plantar fasciitis is important.
Weak Hips
The lower extremity functions as a kinetic chain where each joint and muscle group impacts the others. The hip is an important segment of this chain, significantly influencing the alignment and function of the segments below it, including the knee and, more importantly, in our case, the foot.
When hip muscles are weak, particularly the hip abductors and external rotators, the stability of the entire lower extremity can be compromised, leading to overpronation at the foot.
A case study of a 55-year-old woman with plantar fasciitis foot reinforced this concept. Treatment in the form of hip strengthening exercises, addressing the identified hip abductor muscle weakness, when targeted hip strengthening exercises were performed, led to significant alleviation in heel pain, especially during long-distance walking.
Weak Foot Core
Your foot core consists of the muscles that support the plantar fascia and arch. It is suggested that plantar fasciitis might be associated with foot muscle weakness.
A study compared the volume and strength of the foot core of healthy patients with those suffering from chronic plantar fasciitis. The findings revealed a decrease in the foot core's volume and strength in patients with plantar fasciitis compared to those without.
When these muscles are weak, your plantar fasciitis has to work overtime to support the arch, leading to overuse and subsequent plantar fasciitis.
High Arches
Foot arches range from low (flat feet) to high. Your feet being too far in either direction can lead to plantar fasciitis.
High arches, just like their low counterparts, can contribute to the development of plantar fasciitis. When your arches are significantly elevated, your feet lack flexibility, placing excessive stress on the plantar fascia. Imagine your arches as the suspension system of a car. A good suspension offers a smooth ride by absorbing bumps, much like how a well-balanced foot arch eases the impact on your feet. Conversely, driving in a car with stiff suspension over a pothole illustrates the jarring effect high arches can have, where the plantar fascia bears the brunt of every step.
Conclusion
Tackling Plantar Fasciitis requires a nuanced understanding of its underlying causes. By delving into what triggers this discomfort, one can tailor a more precise and effective treatment plan, ultimately steering toward a life free from the shackles of heel pain.
