To Understand the Arches; You’ll Need to Understand Some Biomechanics

The human foot has a biomechanical motion that most people have never even heard of; it’s called the Windless Mechanism Motion.
The windlass mechanism is the coordinated action of the layers of muscle, tendon, ligament and bony architecture inside the foot. It maintains arch height and foot function, so the foot can correctly and efficiently carry the weight of the body.

There are actually three arches: 1) the medial longitudinal arch, which stretches on the inside of the foot from the heel to the ball, 2) the lateral longitudinal arch, which stretches on the outside of the foot from the heel to the point just posterior of the ball between the 5th metatarsal head and the cuboid bone, and 3) the transverse arch or more commonly known as the metatarsal arch, which stretches just posterior of the metatarsal heads.

If you examine the design of many shoes, you will see a significant flaw. They seem to assume that the foot’s arches are stationary while the body is in motion. This is incorrect. Human foot arches are designed to move with the rest of the foot similar to the struts on a car. The arches need to move for proper foot function. If an arch is not working efficiently, it can cause bio mechanical imbalances of the foot that affect the entire body; issues like knee pain, hip pain, and even back issues can occur over time.

The Windlass Mechanism is often considered one of the most impressive natural features of the human body. Engineers have copied the natural windlass mechanism of the human foot when designing machines capable of carrying heavy loads (from the American Podiatric Medical Association).

Windlass Examples

If the foot moves incorrectly, the windlass mechanism is compromised and will not work efficiently. Most runners are familiar with the plantar fascia. It has a critical role in normal mechanical function of the foot, contributing to the windlass mechanism. When the toes are dorsiflexed in the propulsive phase of gait, the plantar fascia becomes tense, resulting in elevation of the longitudinal arch and shortening of the foot. You can envision it as a cable being wound around the drum of a windlass; the plantar fascia being the cable, the metatarsal head the drum, and the handle, the proximal phalanx. Therefore, the plantar fascia has a number of roles, the most important of these including supporting the arch of the foot and contributing to the windlass mechanism.

The plantar fascia contributes to support of arch of the foot by acting as a tie-rod, where it undergoes tension when the foot bears weight. It carries up to 14% of the total load of the foot – something you’ll more than notice you ever aggravate it.