Everything You Need to Know About Flat Feet

Flexible flat foot (the most common)

Rigid flat foot (less common, and more severe)

Individuals with flexible flat feet appear to have an arch when there is no weight on the foot but as soon as weight is applied the arch flattens out, placing the tendons, ligaments and muscles of the foot at a mechanical disadvantage.

Individuals with rigid flat feet appear to be without an arch contour, even when no weight is being applied. This is generally considered a more severe type of flat foot because the foot is basically nonfunctional in respect to its intended purpose of propulsion.

Flat feet affect over 30% of the world’s population. Known as Pes Planus in the medical field, flat feet are considered more of a structural condition rather than a diagnosable problem but one that can cause problems in early adolescence and adulthood. To thoroughly understand how flat feet can affect gait, one must have some basic knowledge of anatomy.

In human anatomy, tendons attach muscle to bone, ligaments attach bone to bone. Ligaments are primarily there for structural support between the bones whereas tendons are responsible for movement of those structures. There are important ligaments and tendons that help the arch of the foot store and return energy. The first ligament of note is the plantar fascia. The plantar fascia is an important ligament that extends from the heel to the metatarsals (ball of the foot).and toes. Think of the arch of the foot as a hunting bow and the plantar fascia as the bow string. For propulsion, the arch flattens out slightly which pulls on that bow string, ready to release that stored energy. Individuals with flat feet cannot prepare that bow efficiently.

Flat feet cause a condition called pronation where the foot is everted (rolled in toward the medial side of the foot). Pronation is the root of all evil in foot biomechanics because it causes the interdigital spaces to be out of alignment and the tendons and ligaments of the foot and ankle to be placed at a mechanical disadvantage.

The bones of the foot should fit together like a jigsaw puzzle and excessive pronation disrupts these alignments causing foot and ankle pain in the short term and osteoarthritis down the road. All people with flat feet are pronated however all individuals with pronation are not necessarily flat footed.

At heel strike, the heel contacts the ground with the body’s mass behind the plane of the heel and the foot dorsiflexed (pointed up). All the body’s mass and momentum is exerting force on a very small part of the heel.

During midstance, the heel and ball of the foot are contacting the ground at the same time and the body is directly above the foot. It is in this phase that the foot is the most vulnerable because the foot is at its most flexible in order to adjust to uneven terrain.

As the tibia passes over the centerline of the foot the bones of the midfoot “lock up” in order to provide a rigid lever for the body to push against in toe-off. At heel-off, the ball of the foot is contacting the ground and the heel is off the ground (plantarflexion), as the foot prepares for its final, propulsive phase, toe-off.

Toe-off is the phase in which all the energy that was stored in the first 3 phases of gait are released to facilitate movement.

How efficiently these structures have stored this potential energy determines how effectively this energy can be released. Individuals with flat feet and thereby pronation, essentially adds another phase of gait to compensate for this rolling in.

After midstance, whereas the normal foot would be heading into heel off, the flat foot must deal with the excessive pronation prior to proceeding to this next step. This “extra” phase of gait essentially slows down the gait cycle and delays the propulsive phase. There are important ligaments and tendons that help the arch of the foot store and return energy.

Individuals with flat feet cannot load a spring because the elastic band cannot be stretched and therefore an unstretched elastic band can return no energy. Sometimes individuals with flexible flat feet develop an inflammation of the plantar fascia known as plantar fasciitis. Plantar fasciitis is a common condition that affects nearly 3 million people a year in the US alone and is responsible for approximately 700,000 office visits annually.

It presents as pain upon arising first thing in the morning or after prolonged periods of sitting. A second important ligament is the spring ligament, a thick fibrous tissue band that connects the calcaneus (heel bone) to the navicular bone. Individuals with flat feet lack some of the spring action that these two ligaments help provide.

Since the arch is already flat and cannot load the tendons of the foot and their associated ligaments the body must rely on other structures to take up the slack. Flat feet are not necessarily considered a problem for the average person if it presents no pain. Although having flat feet can inhibit athletic performance, many elite athletes with this condition have no problem performing at a high level and in fact many of our most elite athletes in football, baseball and track “suffer” from flat feet.

Shoe insoles can provide much needed support and cushioning for the flat foot. Insoles, generally referred to as arch supports, are aftermarket inserts that replace the standard insoles that come with shoes or sneakers. These insoles provide added arch support to keep the bones, tendons and ligaments of the foot more in a neutral alignment.

This alignment is crucial in helping the ligaments and tendons gain some of their functionality back in the concentric and eccentric phases of gait. In addition to support, shoe insoles or orthotics can provide some of the cushioning that the flat foot cannot. Custom orthotics are full-custom supports designed specifically to the unique contours of an individual’s foot.

Sometimes individuals with flexible flat feet develop an inflammation of the plantar fascia known as plantar fasciitis. Plantar fasciitis is a common condition that affects early 3 million people a year in the US alone and is responsible for approximately 700,000 office visits annually. It presents as pain upon arising first thing in the morning or after prolonged periods of sitting.

A second important ligament is the spring ligament, a thick fibrous tissue band that connects the calcaneus (heel bone) to the navicular bone. Individuals with flat feet lack some of the spring action that these two ligaments help provide.

Since the arch is already flat and cannot load the tendons of the foot and their associated ligaments the body must rely on other structures to take up the slack. Flat feet are not necessarily considered a problem for the average person if it presents no pain. Although having flat feet can inhibit athletic performance, many elite athletes with this condition have no problem performing at a high level and in fact many of our most elite athletes in football, baseball and track “suffers" from flat feet.

To date, insoles have been passive devices in that they only receive input forces from the body and thereby generate no force themselves. VKTRY Performance Insoles are the world’s only carbon fiber insoles designed to be dynamic devices. VKTRY Performance Insoles (VKs), store the energy that is generated by the body in normal motion and returns it directly into the ground, providing the user with dynamic support and cushioning to optimize performance and comfort while protecting from injury.

At heel strike, VKs provide a diving board effect in order to absorb shock and provide a smooth transition into midstance. At midstance, VKTRY’s patented contour provides further shock absorption and protection for the foot during this vulnerable stage. At heel-off, VKs store the energy that the flat foot cannot and return that energy assisting the plantar fascia, spring ligament and posterior tibial tendon for efficient gait.

VKTRY Performance Insoles are available in 5 different Pro (stiffness) levels based on the individuals shoe size, activity and weight. VKTRY’s proprietary algorithm dials in the appropriate level of spring for best results for all foot types. VKTRY also offers three different top cover thicknesses to fit into the tighter profile of cleated and specialty shoes.