Learning More About Foot Biomechanics

The weekly stream, PodChatLive that is the live show for Podiatrists for getting some free ongoing continuing learning has had on many prominent and well known guests in the podiatry profession that generously and readily give there time for it to respond to questions and discuss their area of expertise. The videos of the live chat are on YouTube and the website and the podcast version is on most podcast platforms. An earlier guest in the series was Dr. Kevin Kirby, DPM where he discussed his seminal and well-known publication on rotational equilibrium, his views on the tissue stress model and also his viewpoint on whether or not any present comprehension of Root Theory is required to examine and successfully treat our clients. The questions created some interesting chat throughout the episode.

Kevin Kirby graduated in 1983 with the California College of Podiatric Medicine after which carried out his first year surgical residency in Palo Alto, California at the VA Hospital. Then he spent his subsequent post-graduate year undertaking the Fellowship in Podiatric Biomechanics at CCPM when he also completed his masters degree.

Dr. Kirby has published or co-authored 28 publications in professional journals, has authored or co-authored 5 chapters in books, and has now published 5 books on foot and lower limb biomechanics and foot orthotic treatment, all of these have now been converted into Spanish language versions. Kevin established the Subtalar Joint Axis Palpation Technique, the Anterior Axial Radiographic Projection, the Supination Resistance Test, the Maximum Pronation Test and the Medial Heel Skive and Lateral Heel Skive Techniques. He has additionally created and formulated the Subtalar Joint Axis Location and Rotational Equilibrium Theory of Foot Function and has co-developed the Subtalar Joint Equilibrium and Tissue Stress Approach to Biomechanical Therapy of the Foot and Lower Extremity. Dr Kirby has lectured widely throughout the world on lots of occasions and has moreover spoken publicly greatly all around the USA.

What is the the windlass mechanism in the foot?

The windlass is that device that are used by the mariners on yachts to wind the rope around to make it less difficult to move the sails. Within the foot there is a mechanism that is called the windlass mechanism that gets its name from this equipment used on yachts. There is a ligament like structure beneath the foot called the plantar fascia that is at one end connected to the bottom of the heel bone and at the other end to the great toe. When we're walking and the heel comes off the ground, the foot rotates around the great toe where this ligament is connected, tightening the ligament as it winds around the windlass of the first metatarsal head. This is the windlass mechanism of the foot. It is a crucial functionality as that ligament is what supports the arch of the foot, therefore it really should function adequately and quickly for normal biomechanics. This is the foots own natural arch support mechanism.

There are a number of conditions related to the windlass mechanism not functioning properly. When the windlass does not work, then the arch of the foot will fail from this lack of support and a range of disorders may develop as a result of that such as bunions and plantar fasciitis. The reason for the windlass not working properly can be multiple such as the force required to establish it just being way too high, so the body has to work harder to make the windlass work. If that hard work does make it function, then that is an increased energy expenditure that could be very fatiguing. Clinicians use different design characteristics in foot orthoses to enhance the windlass mechanism and to make walking easier and more effective. If the windlass can be established easily during walking or running is not going to need so much and the foot will naturally support its own arch.