Biomechanics Knowledge Center

What is Biomechanics?

Clinical biomechanics is a medical specialty that combines anatomy, physiology, and physics in order to study the structure and function of the human musculoskeletal system.  This system is comprised of articulating levers which are acted on by the dynamic force of muscles, the kinetic force of the moving body, and the static forces of gravity and ground reaction force.  Together, they present a complex series of interrelated physical phenomena undergoing a constant flux with each change of position.  

As the foot is the first thing to strike the floor when walking and running, it stands to reason that if the foot strikes the floor incorrectly, or the normal movement of the foot is compromised, the whole body above it is affected as movement patterns are altered.  This leads to repetitive movement abnormalities, occurring every time the foot hits the floor.  Over time, and over miles, this can lead to complex biomechanical problems arising in many areas of the body, from repeated stress and compensation.  This causes pain and discomfort for athletic endeavors as well as normal activity.  With proper analysis, many biomechanical abnormalities may be corrected with functional orthoses and rehabilitation.  

What are Functional Foot Orthoses?

Functional foot orthoses (FFO) is a medical device that is placed in the shoe in order to influence, remedy, control and/or equalize the patterns and forces affecting the foot in order to reduce pathological and damaging load forces and to increase normal foot and lower leg function during weight bearing activities.

In the broadest of terms foot orthoses are divided into two main categories: non-prescription foot orthoses and prescription foot orthoses. Working definitions of both of these categories are provided below:

Non-prescription Foot Orthoses: Prefabricated device designed to suit as many people as possible.  This is a cost effective alternative for adults as well as for growing children.

Prescription Foot Orthoses:  Custom orthoses are constructed by using a mold impression of the patient's feet in neutral position. Important weight-bearing and non-weight-bearing measurements are accounted for in the individual's prescription.

Prescription foot orthoses can be divided into two main categories based on their intended purpose:

• Functional foot orthoses are used to influence motion of the joints in the foot and lower leg in order to increase the range of motion and equalize the loading patterns in injured and/or inflamed plantar aspects of the foot during weight bearing activities.
• Accommodative foot orthoses are used to offload high pressure areas of the plantar surface of the foot during weight bearing activities.  These prescription devices are fabricated to become a full contact surface under the foot and help reduce callousing and alleviate high pressure areas of the foot.

Proper Shoe Selection

Shoes become the foundation of the orthotic device which can either increase or decrease the effectiveness of the prescription.  Proper footwears made with stable materials benefit the use of the devices by slowing and controlling forces and range of motion within the foot.

Orthotic Tips:

• Wear shoes that work well with your orthotics.
• Bring your orthotics with you whenever you purchase a new pair of shoes.
• Wear socks or stockings similar to those that you plan on wearing when you shop for new shoes.
• Return as directed for follow-up evaluation of the functioning of your orthotics.  This is important for making certain that your feet and orthotics are functioning properly together.