As Sandals Come Out, Let’s Talk About Foot Biomechanics and Footwear.
Summer is here, and that means flip-flops are making their annual return. They’re convenient, easy to
slip on, and perfect for a day at the pool or at the beach. However, many people don’t realize that the
footwear they choose (especially flip-flops) can have a significant impact on how they move, feel, and
function.
Because the feet serve as the foundation of the body, even subtle changes in foot mechanics can
influence movement patterns throughout the entire kinetic chain. For some individuals, prolonged use
of unsupportive footwear may contribute to foot, knee, hip, or low back discomfort and/or pain.
1) How Flip-Flops Affect Spinal Health and Body Alignment
Flip-flops are a popular footwear choice during the warmer months. While they offer convenience and
breathability, they generally provide minimal support for the foot and ankle. The feet are often referred
to as the body’s foundation, and, just like a house built on an unstable foundation, the rest of the body
may be forced to compensate when foot mechanics are altered from the usage of flip-flops.
Flip-flops have been around for centuries, and have gained widespread popularity in the United States
during the 1950s and 1960s. Their convenience remains their greatest selling point, but this
convenience often comes at the cost of support and stability.
Unlike athletic shoes or supportive sandals, flip-flops typically lack:
- Arch support
- Heel cushioning
- Rearfoot stability
- Motion control features
- A secure attachment to the foot
Because the sandal is only secured by a strap between the toes, the foot must work harder to keep the
footwear in place. Many individuals subconsciously grip with their toes while walking, creating
increased demand on the intrinsic muscles of the foot. Normally, this would be good. However, most
people don’t know how to do this properly; their muscles are untrained in this particular bodily
demand, which can subject the wearer to pain (more on this later).
Research has shown that people often alter their walking mechanics while wearing flip-flops. Common
changes include:
- Shorter stride lengths
- Reduced heel strike
- Increased toe gripping
- Less ankle dorsiflexion during gait
- Altered loading patterns throughout the lower extremity
While these changes may seem insignificant, they are repeated thousands of times throughout the day.
Over time, altered movement patterns may increase stress on the plantar fascia, Achilles tendon,
knees, hips, and the lower back.
2) The Kinetic Chain: From Foot to Spine
The body functions as an interconnected system known as the kinetic chain. This chain allows for the
complex movements that we make each day. When one area is unable to perform its job efficiently,
another area often compensates.
The choice to wear flip-flops can create changes that extend far beyond the foot itself. As mentioned
previously, flip-flops can alter gait mechanics and reduce stability during walking. This often leads to
compensations throughout the entire lower extremity, and even into the spine.
For example:
- Excessive foot pronation may increase internal rotation of the tibia.
- Increased tibial rotation can influence knee mechanics.
- Changes at the knee may affect hip positioning and muscle activation.
- Hip compensation can alter pelvic alignment.
- Pelvic changes may contribute to increased stress on the lumbar spine.
The body is remarkably adaptable and will often find a way to continue moving despite these changes.
However, compensation does not always equal optimal movement. Over time, repetitive
compensations may contribute to discomfort or movement inefficiencies.
This doesn’t mean flip-flops directly cause back pain. Rather, they may become one contributing factor
among many, especially in individuals who already have limitations in mobility, strength, or stability.
3) Better Summer Shoe Options
Wearing flip-flops occasionally is completely reasonable. The key is understanding when they are most
appropriate, and ensuring that they are not your only footwear option throughout the summer.
For short walks, pool days, or trips to the beach, flip-flops may be perfectly acceptable. However, if
you’re planning on spending hours standing, walking, exercising, or traveling, additional support may
be beneficial.
Minimalist Options:
For individuals who prefer less restrictive footwear, minimalist shoes can be a great option.
These shoes are often characterized by:
- Wider toe boxes
- Flexible soles
- Minimal cushioning
- Low-drop or zero-drop designs
Minimalist footwear may encourage greater foot muscle activity and allow the foot to move more
naturally. These types of shoes are excellent for people with higher arches, as they typically require less
support. However, transitioning too quickly can overload tissues that are not accustomed to the
increased demand (i.e the intrinsic foot musculature). A gradual transition is typically recommended
with these types of shoes.
Supportive Options:
Supportive footwear may be beneficial for individuals who:
- Spend long hours on their feet
- Have a history of plantar fasciitis
- Experience chronic foot pain
- Have significant arch collapse
- Need additional stability for work or exercise
Supportive shoes often include:
- Structured arch support
- Improved shock absorption
- Better heel control
- Enhanced stability features
The “best” shoe is often the one that matches your anatomy, activity level, and goals.
4) How We Evaluate the Foot’s Impact on Posture
At IHS, we recognize that every foot is different. Some individuals function exceptionally well with
minimal support, while others require more guidance from their footwear.
When evaluating a patient, we assess:
- Arch structure
- Foot posture
- Ankle mobility
- Balance and stability
- Walking mechanics
- Lower extremity alignment
- Hip and pelvic function
Footwear is just one piece of the puzzle. We also consider how the foot interacts with the ankle, knee,
hip, and spine.
Sometimes the foot is the primary driver of symptoms. Other times, foot discomfort may actually be
the result of dysfunction occurring higher up the kinetic chain.
A comprehensive movement assessment helps us to determine where the true problem originates and
what interventions may provide the greatest benefit.
5) Foot Exercises for Support and Stability
There are numerous exercises that can improve foot strength, arch control, and ankle stability.
Depending on your arch structure, symptoms, and daily demands, the exercises prescribed at IHS are
tailored specifically to your needs. However, several foundational exercises are commonly utilized to
improve foot function and create a stronger foundation.
- Towel Pulls: utilizing a towel, use your toes to pull the towel in towards your foot. The intrinsic
muscles located on the bottom of the foot will need to be activated to ensure that this is done
correctly (tip: this exercise is much easier to complete on hardwood or tile floors, as opposed to
carpet). - ToePro Calf Raises: the ToePro device is wonderful for improving intrinsic foot muscle activity. By
utilizing toe flexion on the foam of the ToePro device, this will help facilitate activation of the intrinsicfoot musculature. Adding in a calf raise (both straight-leg and bent-knee versions) after grasping thefoam of the device allows for improving activity of the gastrocnemius and soleus muscles. - Banded Inversion/Eversion: these two moves are excellent for training the tibialis anterior and
posterior (inversion), as well as the peroneal muscle group (eversion). Training these muscles will
create greater stability around the ankle and foot. This can be done with a band to increase the
challenge level of the move.
Programming Recommendations:
These exercises can generally be performed 2-3 times per day for 10-12 repetitions.
The goal is not simply to strengthen the foot, but to improve awareness and activation of the intrinsic
foot musculature, calf complex, tibialis muscles, and the peroneals.
Over time, improved strength and coordination within these muscle groups can create a more stable
foundation for movement, helping support the feet, ankles, knees, hips, and spine.
Final Thoughts:
Flip-flops aren’t inherently bad for you. They are simply one tool in the footwear toolbox. The key is
understanding their limitations, and being able to adapt to those accordingly.
For short-term use, they can be perfectly appropriate. However, prolonged use may contribute to
altered gait mechanics, reduced stability, and increased demands on the structures of the foot and
lower extremity.
If you’re experiencing persistent foot/ankle, knee, hip, or back pain, it may be worth taking a closer
look at your footwear choices and movement patterns. Because when the foundation changes, the rest
of the body often follows, for better or for worse.
Content Provided By: Dr. Josh Monzel
