Written by: John Baker and Lily Hoog-Fry
If you’re like us, your apparel choices are primarily driven by function, with fashion being a secondary consideration. While we acknowledge that fashion takes precedence in certain scenarios, we believe that function should generally dictate form. This means that the intended purpose should always inform the materials and design of what we wear, especially when it comes to footwear.
Consider the analogy: bringing a NASCAR car to a rally race is a recipe for failure. Similarly, wearing shoes designed principally with fashion in mind can lead to significant physical dysfunction. The wrong footwear choice can have far-reaching negative impacts on your body.
It’s crucial to select footwear that supports optimal foot function. Your feet are your primary point of contact with the world, influencing how the rest of your body aligns and moves. Functional footwear not only enhances your performance but also significantly reduces overall wear and tear throughout your entire body. Conversely, dysfunctional footwear can severely hinder performance and lead to a cascade of aches and pains, affecting your ankles, knees, hips, and even your spine.
Ankle, Knee and Hip Dysfunction/Disability in Our Time
The Centers for Disease Control and Prevention (CDC) reports that a staggering 21% of adults in the United States experience pain in the foot, knee, or hip. This number becomes even more concerning when we look at specific age groups: 29% of individuals aged 30-44 years report pain in these areas, escalating to 43% for those aged 45-64 years, and reaching 50% for those over 65 years (Lucus et al, 2021). This clear trend highlights a growing problem that affects a significant portion of the population as they age.
Even more alarming is the prevalence of back pain!
- 28% of Individuals aged 18-29 years old reported back pain.
- 35% of Individuals aged 30-44 years reported back pain.
- 44% of individuals aged 45-64 years reported back pain
- 45% of those over 65 years reported back pain (Lucus et al, 2021).
These statistics reveal a major health crisis impacting everyday individuals and placing a substantial burden on the United States Healthcare system. While some pain-generating factors like automobile crashes or genetic predispositions are currently beyond our immediate control, we do have significant insights into how shoes and our feet contribute to chronic pain.
We understand the intricate relationship between footwear and body mechanics, particularly how it contributes to hip pain and other musculoskeletal issues.
The Sole of Modern Shoes
Conventional footwear often utilizes various materials and construction methods. The most common materials in shoe construction include EVA (Ethylene-Vinyl Acetate), Polyurethane, Air Cushioning, and Foam Cushioning. Each of these possesses distinct properties that dictate their specific applications and uses within a shoe.
EVA is celebrated for being lightweight and flexible, qualities that initially seem beneficial. However, its significant drawback is a relatively short lifespan. This material degrades and deforms much faster than other options, leading to an exaggerated, biomechanically unsound ankle slope. As EVA wears down, it essentially transforms into an angled wedge beneath your foot instead of providing a flat, symmetrical, and stable surface. This instability can cause harmful displacement throughout the kinetic chain, impacting the knee, hip, pelvis, spine, and even the upper body (Chen et al, 2020) (Reutimann et al, 2022) (Huang et al, 2020).
Polyurethane, in contrast, is known for its density and durability. This material offers greater resistance to wear and tear, theoretically prolonging the comfort of your feet and the life of your wallet. However, studies show that its rigid construction increases stress and force (including contact force, bending force, and torsional force) on the hip joint during movement (Palmowski et al, 2021) (Malisoux et al, 2022). Consequently, this material is not ideal for individuals with a history of hip pain or dysfunction, nor for those seeking to prevent future hip issues.
Air Cushioning systems integrate a series of air pockets to provide both cushion and support. Like other materials used in shoe construction, air cushioning can lose its shape over time. While the more durable external scaffolding around these air pockets might mitigate the postural effects of wear compared to some other shoe materials, the gradual breakdown can still compromise stability and support.
Foam cushioning is frequently used for insole comfort. Due to its typical thinness, non-uniform wear in foam insoles generally has less detrimental effects on posture and body positioning compared to thicker materials over time. However, when foam insoles are combined with an outer sole made from another material, they can inadvertently exacerbate overall detrimental effects. This creates a scenario where the foot attempts to stabilize itself on two uniquely unstable and deformed surfaces, compounding the problem of functional instability.
Not So Cushy, It’s Just a Bunch of Fluff
Ironically, cushioning, even when new and seemingly providing uniform dampening of forces, may have a paradoxical relationship with safety. Rather than offering genuine protection, excessive cushioning can actually increase stress on the body and its joints. This is because it encourages unnatural movement patterns, preventing our bodies from utilizing their inherent spring mechanisms to naturally decrease joint loading. We essentially rely on a less-than-one-inch cushion to absorb forces that originate much higher in the body, often 5 ½ feet away from the shoe itself. This disconnect can lead to seemingly unrelated issues, like neck pain, despite no direct trauma to the neck.
Relying solely on shoe cushioning is akin to trying to stop a freight train with a ping-pong paddle. Research overwhelmingly suggests that developing proper movement mechanics is far more effective than simply increasing the cushion between your foot and the ground (Robbins & Waked, 1997) (Kulmala et al, 2018) (Leiberman et al, 2010) (Lam et al, 2018).
Here’s the Takeaway
While cushioning might offer temporary relief in certain situations, in the long run, depending on it for foot, ankle, knee, and hip pain is a temporary fix, much like taking aspirin for a headache. It doesn't address the underlying weakness or gait issues causing the pain. In fact, relying on commonly sought-after "helpful" cushioning can create a self-perpetuating cycle of foot deformation, foot weakness, and upstream pain throughout the body.
In our next discussion, we will delve into the precise ways that cushion, heels, and hard soles alter the mechanics of our spine, exploring why these factors might actually be the root cause of those persistent headaches.
