Flip-flops: relief for your feet or a health risk?

We all love the feeling of freshness, and even, you could say, a certain liberation, when we leave our winter shoes in the closet and slip the soles of our feet into a pair of flip-flops . In fact, while they may not be the most comfortable walking shoes in the world, the urge to let your feet "loose" is overwhelming.

However, if we let ourselves get carried away by this motivation, unfortunately, the health of our feet can be harmed. And we're not talking about temporary discomfort, but rather plantar fasciitis , a sprain, or tendonitis.

With the consequences of flip-flops in mind, let's focus on how and why this footwear can be such a bad travel companion, at least from a health perspective.

"These flip-flops, lacking basic elements such as rear support, adequate cushioning, or arch support, do not respect the natural biomechanics of the foot. This forces constant contraction of the toes, especially the short toe flexor, to keep the shoe in place, generating unnecessary muscle strain," explains Alberto Bermejo, physiotherapist, podiatrist, and professor of Physiotherapy at the European University.

As if that weren't enough, since they typically have a thin, unstructured sole, " they don't properly absorb the impacts of walking , which increases the risk of overuse injuries or upward biomechanical compensations," Bermejo points out. Therefore, "it's not a healthy type of footwear if used regularly and for long periods of time."

Sometimes they might even be safe.

All of these inconveniences could be overshadowed in certain situations. The recommendation to be moderate in the use of flip-flops "should not be understood as an absolute prohibition," the podiatrist emphasizes, "since there are specific contexts in which the use of flip-flops is justified and can be considered safe: for example, in public showers, locker rooms, at the beach, or in the pool, where a hygienic barrier or a practical and quick solution is sought."

However, although they could be considered appropriate footwear for the circumstances, occasional use and short duration are still paramount. And, above all, "do not wear them for long walks or sustained exertion," insists the expert, who emphasizes that "even in these contexts, the use of anatomical models with some plantar reinforcement and good grip should be prioritized to minimize risks."

In addition to the time factor (how long we wear flip-flops), the type of surface we walk on is also crucial when assessing the risks to which we are exposed. In this sense, it is advisable to avoid this footwear in "urban environments, with uneven surfaces, or when performing tasks that involve physical exertion or frequent movement," advises Bermejo.

In these situations, the foot works under unfavorable conditions, lacking stability, support, and protection, which can lead to functional and structural alterations. "People with flat feet , hallux valgus (bunions), previous plantar fasciitis, tendinopathies , or postural disorders are especially at risk of worsening their symptoms if they overuse flip-flops," he warns.

At worst…

According to the podiatrist, overuse of flip-flops can aggravate existing foot problems. However, it can also cause them. These are the main pathologies that, according to Bermejo, could appear:

• Plantar fasciitis. Without support from the longitudinal arch of the foot, the plantar fascia can become overstressed . The constant tension during walking, combined with direct impact without cushioning, promotes inflammation of this structure, causing heel pain, especially in the morning or after periods of rest.
• Tendinitis . It's common to find overuse of tendons such as the flexor hallucis longus, the Achilles tendon, or the posterior tibial tendon, as the foot performs compensatory contractions to hold the shoe in place. This repetitive strain can cause overuse, which can lead to tendon inflammation.
• Sprains . Because these shoes are open and lack lateral or rear support, ankle stability is significantly reduced. This increases the risk of sprains , especially when walking on uneven terrain or making sudden movements.
• Metatarsalgia and digital overload. Inadequate weight distribution, combined with constant digital contraction, can cause pain in the forefoot and calluses . Occasionally, flat, poorly supported footwear can promote the development or worsening of Morton's neuroma. This condition, which consists of a thickening of the interdigital nerve (usually between the third and fourth metatarsals), is influenced by increased pressure and compression on the forefoot.
• Hallux valgus (bunions). For people who already have bunions , prolonged use of flip-flops can cause discomfort and worsen the alignment of the big toe, so it's best to choose shoes that offer greater support and support.
• Postural changes. Prolonged use can affect the way you walk and cause imbalances that affect other joints.

Furthermore, "these risks are increased if the individual has previous gait disorders or lacks sufficiently trained intrinsic foot muscles," the expert adds.

Collateral damage: the back

As if the list of pathologies above weren't long and serious enough, the impact of wearing flip-flops "can extend beyond the foot and affect other structures, such as the knee, hip, or back (especially the lower back, known as the lumbar region )," warns the physiotherapist.

“When support and gait mechanics are altered, upward postural compensations can occur. For example, if the foot lacks proper plantar support, pronation can increase (especially during full stance), causing internal rotation of the tibia and femur, imbalances or misalignments in the pelvis, and overloading the lumbar muscles ,” Bermejo explains.

Furthermore, “when the pelvis becomes unbalanced due to poor alignment of the foot and leg, tension can occur in the sacroiliac joint, which connects the spine to the pelvis and is an area where pain can frequently be referred to the lower back or buttocks ,” he adds.

Barefoot footwear requires gradual adaptation and avoidance of prolonged periods of use.

Another consequence of the alteration of support and gait is muscle overload (especially in the calves and paraspinal muscles) and lower back pain, which can cause muscular or joint conditions throughout the spine .

On the other hand, in many cases, flip-flops tend to have a flat sole, which does not usually offer good absorption/cushioning of the impact generated during walking, "which causes the load forces to be transmitted more directly to the aforementioned upper joints, including the lumbar spine, causing or aggravating pain in that area, especially if walking or standing for long periods," he points out.

Finally, for many people, especially those with hyperlordosis or abdominal weakness, wearing completely flat shoes "causes anterior tilting of the pelvis, which increases the lumbar curvature, increasing tension in the area," the expert adds.

How to choose the perfect summer shoes?

Considering all of the above, it's clear that flip-flops, despite being the coolest, aren't contenders for the podium for best summer footwear . So, if we want to wear cool, yet healthy, footwear, what should we keep in mind?

According to Alberto Bermejo, the ideal is to "choose footwear that combines breathability and coolness, that isn't too flat, and that provides good support for the foot." He adds: " Anatomical sandals , which offer adjustable support at the heel and instep, and an anatomically shaped insole that respects the arch of the foot, are an excellent alternative to flip-flops."

There are models with breathable materials, medium-density soles, and reinforcements that help distribute the load of body weight properly.

Barefoot, a good option, but with nuances

Lightweight barefoot shoes can also be considered. as an alternative to flip-flops. However, "you have to be careful because this type of footwear is usually flat and requires gradual adaptation , avoiding prolonged periods of use, especially if you are not used to wearing it," warns the expert.

Finally, the expert reminds us of the importance of not neglecting foot health during the summer months, since "these types of changes can have a lasting impact if not corrected in a timely manner."

In any case, "if there is any foot condition or doubts about the most appropriate type of footwear, it is best to see a podiatrist, who can assess each situation individually and offer the best guidance based on each individual's clinical needs," he advises.