The flip-flop is a simple, flat, open sandal secured by a thong between the toes, making it a staple of warm weather footwear. While prized for convenience, its effect on foot health is debated. The answer to whether this casual footwear is beneficial or harmful depends on the frequency of use and the sandal’s specific design. Due to the mechanics of walking in a shoe with minimal structure, experts recommend cautious, limited use.
How Flip Flops Change Foot Biomechanics
The lack of a secure strap around the heel forces the foot to actively work to keep the sandal attached during the swing phase of the gait cycle. This results in the unnatural “toe-gripping” action, where the toes curl downward to maintain contact with the shoe. This constant flexion strains the muscles and tendons on the top of the foot and alters the natural movement sequence of the foot and ankle.
Studies show that wearing typical thong-style flip-flops causes a noticeable change in a person’s gait. Wearers often take shorter strides and walk at a slower speed compared to wearing athletic shoes. This altered movement reduces the normal heel-to-toe roll-off motion and increases the angle of the ankle joint, which is a compensatory move to keep the foot from slipping out of the shoe.
This instability and lack of support mean the lower leg muscles must compensate for the foot’s reduced function. The muscles around the ankle and the lower leg, such as the tibialis anterior, show increased activation as they work harder to stabilize the foot and lift the unsupported sandal during the swing phase. Over time, this cumulative strain and the resulting changes in foot mechanics can ripple upward, potentially affecting the alignment and function of the knees, hips, and lower back.
Common Foot Health Issues Linked to Poor Support
The chronic stress caused by the altered gait and lack of arch support can lead directly to several common foot and lower extremity problems. One of the most frequent issues is plantar fasciitis, which involves inflammation of the thick band of tissue running along the bottom of the foot from the heel to the toes. Without a supportive arch contour, the arch collapses, placing excessive tension on the plantar fascia with each step.
The lack of proper heel lift and cushioning can contribute to Achilles tendonitis, inflammation of the tendon connecting the calf muscle to the heel bone. Minimal sole material offers poor shock absorption, increasing impact forces on the heel and forefoot, which can eventually lead to stress fractures in the metatarsal bones. The constant toe-gripping action can also accelerate the development of toe deformities like hammertoes and bunions.
Beyond biomechanical issues, the open design increases exposure risks. The feet are vulnerable to cuts, scrapes, and puncture wounds from debris on the ground. Wearing flip-flops in communal wet areas like public showers or pool decks can increase the risk of fungal infections, such as athlete’s foot, if the material is not properly cleaned.
When to Wear Them and What Features Matter
The appropriate use of flip-flops is restricted primarily to short-distance wear where the convenience of waterproof, easily removable footwear outweighs the need for mechanical support. They are best reserved for walking to a pool, using a communal shower facility, or for very brief errands. They should be avoided entirely for any activity involving long-distance walking, running, or terrain requiring lateral stability.
When selecting a pair, look for models that incorporate specific supportive features to mitigate the common risks. A suitable flip-flop should possess a contoured footbed that mimics the natural shape of the foot, including a noticeable arch support and a deep heel cup to stabilize the foot and prevent overpronation. The sole should be firm and not easily folded in half, indicating a proper midsole for shock absorption and structural integrity.
The strap design is a significant factor in minimizing the toe-gripping reflex. A secure, snug strap, often made from a flexible but non-stretching material, will hold the foot to the sole, reducing the need for the toes to curl. Some designs incorporate a slight heel elevation, typically around a half to one inch, which helps reduce tension on the Achilles tendon and improves stability.