Effects of Minimalist Footwear on Healthy Subjetcs. Randomised Controlled Trial.

Background and current situation

The concept of foot core defines the set of structures responsible for providing dynamic control to the foot; for it to function correctly, the integrity of the three subsystems that comprise it is required, which are:

• Passive subsystem: comprises the bones, joint capsules and ligaments, including the plantar fascia, which form the plantar arch; this is defined by the medial and lateral longitudinal arches and the anterior and posterior transverse arches.
• Active subsystem: includes the intrinsic foot muscles (IFM) and the extrinsic muscles, whose functions are to stabilise and mobilise the foot, respectively.
• Neural subsystem: formed by all the capsuloligamentous and musculotendinous receptors of the active and passive subsystems, in addition to the plantar cutaneous receptors.

Of all the elements that make up the foot core, the importance of the IFM stands out. Some of the most relevant functions of the IFM when acting together are: adapting the position of the foot in the different phases of the gait cycle, stabilising the midfoot and forefoot, improving load absorption and force transmission capacity and controlling foot pronation. The literature has shown that morphological or functional deficits of the IFM are involved in the development of pathologies such as plantar fasciitis, hallux valgus, hammer toes, Achilles tendinopathy and chronic ankle instability.

For the foot core to function correctly, the integrity of the neural subsystem is also essential. Plantar skin sensitivity is a key element in static and dynamic body stability. It is interesting to bear this in mind when treating various pathologies that involve stability deficits and even for athletic performance.