Plantar fasciitis is a common source of heel pain caused by irritation or inflammation of the plantar fascia, a thick band of tissue running along the bottom of the foot. This fibrous tissue connects the heel bone to the toes, supporting the arch and absorbing mechanical shock during movement. When this structure is repeatedly stressed, it can develop micro-tears and chronic irritation. Understanding the specific factors that increase this strain is crucial for managing the condition and preventing severe flare-ups.
Footwear That Increases Strain
Footwear that fails to support the foot’s natural structure is a major contributor to worsening plantar fasciitis pain. Shoes lacking proper arch support, such as ballet flats, minimalist shoes, or most flip-flops, force the plantar fascia to work harder to maintain the foot’s arch. This constant stretching of the fascia places excessive pressure on its attachment point at the heel bone. Extended periods in unsupportive footwear can easily overload an already irritated fascia.
High-heeled shoes mechanically increase tension on the plantar fascia by shortening the posterior chain of the lower leg. Wearing high heels forces the foot into a pointed position, which contracts and stiffens the calf muscles and the Achilles tendon. Since the Achilles tendon connects directly to the heel bone, its tightness transmits a pulling force onto the plantar fascia, exacerbating irritation at the heel.
Even athletic shoes lose their integrity and cushioning over time, leading to poor shock absorption. Continuing to wear shoes past their recommended lifespan—often between 300 and 500 miles for running shoes—means the foot is subjected to greater impact forces with every step. Furthermore, walking barefoot, particularly on hard surfaces like concrete or tile, removes all shock absorption and arch support. This direct, uncushioned impact on an inflamed heel triggers pain.
High-Stress Activities and Loading Errors
The duration and intensity of weight-bearing activities can severely aggravate plantar fasciitis, even when wearing appropriate shoes. Prolonged standing or walking, especially on hard surfaces, causes a continuous accumulation of pressure and strain on the compromised fascia. Occupations that require standing for hours, such as teaching or factory work, often lead to flare-ups because the tissue is not given rest to recover.
High-impact exercises are detrimental, as they introduce a significant shock load that the inflamed tissue cannot handle. Activities like running, dancing, and plyometrics force the foot to absorb the body’s weight repeatedly and rapidly. This repetitive stretching and contracting can lead to further micro-tearing within the fascia, worsening inflammation and pain.
A common loading error is a sudden, rapid increase in physical activity. This “weekend warrior” syndrome involves abruptly increasing the frequency, duration, or intensity of workouts without allowing the fascia time to adapt. The sudden overload can cause acute strain, often leading to immediate and severe flare-ups.
Ignoring pain and attempting to push through exercise is the most damaging behavior for long-term healing. Pain is the body’s signal that the tissue is being damaged, and continuing to stress an injured plantar fascia only delays recovery and increases chronic inflammation. This behavior can also cause a patient to alter their gait to compensate for the pain, potentially leading to secondary problems in the knee, hip, or back.
Underlying Physical Conditions
Several physical conditions increase the mechanical stress on the plantar fascia, making it susceptible to worsening pain. Excessive body weight increases the compressive and tensile forces on the foot. Carrying extra pounds means the plantar fascia must constantly support a greater load, accelerating wear and tear and making it more difficult for the tissue to heal.
Tightness in the calf muscles, specifically the gastrocnemius and soleus, is a significant mechanical factor. Since these muscles connect to the heel via the Achilles tendon, restriction limits the ankle’s ability to flex upwards. This limited motion forces the foot to overcompensate during walking, causing the tight calf to pull on the heel bone and subsequently increase tension across the plantar fascia.
Specific structural issues in the foot alter how impact is absorbed, leading to increased strain. Both excessive pronation (flat feet) and high arches (pes cavus) are less efficient at distributing force. Overpronation causes the arch to collapse and stretch the fascia, while a high arch leaves the fascia overly taut. Both structures are prone to exacerbation if not corrected with proper support.