The arches are held under elastic tension. They are passively secured by strong ligaments and actively maintained by the muscles. Some of these muscles are located in the foot itself, for example in the longitudinal arch between the foot bones and the sole of the foot. Other muscles, which run from the lower leg via long tendons to individual bones of the foot, attach there and in some cases extend to the tips of the toes, also provide this tension and stabilization. These include, in particular, the tibialis anterior and tibialis posterior muscles, the muscles of the long toe flexor and the long great-toe flexor, as well as the peroneal muscles.
While the longitudinal arch extends across the entire sole of the foot, running from the ball of the foot to the heel, the transverse arch flattens out horizontally from the tarsus toward the front and the ball of the foot. The head of the talus is set into the highest point of the arch. Depending on the type of load, it transfers the body's weight to the foot arches and must absorb and transmit up to four to five times the body's weight. The bones are shaped so that they form a hollow space toward the sole of the foot, accommodating the powerful short muscles and the tendons of the long muscles that run down from the lower leg.
The most important, longest, and strongest ligament is the plantar fascia, which can be palpated directly beneath the sole of the foot and is clearly visible in the fifth image from the left.
However, if this effective, natural shock-absorption mechanism is not sufficiently challenged and the muscles are subjected to too little or improper loading, for example due to excess weight, the tension in the foot decreases and the arches flatten. As we age and exercise decreases, the muscles of the foot often atrophy and can no longer fully perform their task of actively absorbing loads and shocks.
Shoes therefore have a special significance in the biomechanics of the foot. If shoes constrict the foot too much, preventing it from moving or allowing it to move only inadequately, the foot muscles atrophy just as quickly. The foot becomes “lazy,” and its performance declines.
Daily foot exercises can counteract this, preferably barefoot. But the right shoe can also help preserve the mobility of the feet. For this, the foot needs enough room inside the shoe while still having secure support, ensuring that the foot and shoe function as a unit.
Foot muscles strengthened through training and functioning properly therefore help maintain the tension of the important foot arches in particular. This enables them to perform their dynamic tasks while walking—especially cushioning the impact of the foot strike—even into old age.
More information on this topic from Dr. Norbert L. Becker can be found at: www.fair2feet.com/
