The term biomechanics is defined by the American Heritage Dictionary as..."the study of the mechanics of a living body, especially of the forces exerted by muscles and gravity on the skeletal structure". Therefore biomechanical pain is pain that is the result of abnormal, or faulty, forces exerted by muscles and/or gravity on the skeletal structure(s).for the sake of simplicity, in this case, the human foot.

However, biomechanical pain can occur in numerous parts of the body, and for numerous reasons. We will limit this discussion to biomechanical pain within the structures of the foot, or structures affecting the foot or are affected by the foot.

To understand the essence of biomechanics, it is necessary to have a basic appreciation of the way joints function within the foot. There are normally 26 bones and approximately 30 joints in each foot (with over 100 ligaments and 15 muscles in three different layers!).

The major joints within the foot responsible for transferring weight from one foot to the other are not typical ball and socket joints like the ankle, knee, or hip joints. They are small joints that exist between small bones, and their motion(s) differ from the three previously mentioned joints, in that the bones slide and/or glide back and forth between each other with relatively little range of motion.

There is an average range of motion of all joints within the human body. This average is determined by anatomical studies, as well as clinical exams of thousands of joints. Measurements that are outside of this average range are not considered 'abnormal', just as measurements that are within this range are not considered 'normal'. This average range of motion for each joint is just a starting point for allowing anatomists, researchers, and clinicians to study, evaluate, and treat individual variations.

Another major difference in the way foot joint(s) function is that many anatomical joints (a joint between two specific bones) may (and do) function together in unison as a functional joint.

Any athlete, especially runners, who has had foot pain or problems in the past, have probably heard, or seen the words pronation and supination; or over-pronation and over-supination.

Pronation and supination are terms used to describe individual (normal) foot motions. In simplest terms, pronation is observed (within the foot) as the arch collapsing when you are walking (weight bearing), or your foot moving out and away from the midline of your body when your foot is off the ground (non-weight bearing)

The opposite motion supination, is observed as the arch elevating and walking more on the outside of your foot (weight bearing), or your foot moving in and towards the midline of your body while non-weight bearing.

It is important to understand these basic foot motions, as individual variations within the quality, degree, and timing of pronation and supination are at the forefront of the majority of causes of biomechanical foot pain.

There is an average amount of pronation and supination that take place within the functional joints of each foot during normal locomotion (walking). There are also specific time(s) during the gait (walking) cycle when pronation and supination should take place.

The evaluation of the quality, degree, and timing of pronation and supination during the gait cycle is referred to as gait analysis. The typical gait analysis consists of over 30 different observations that occur in, between, and around the forefoot, the rearfoot, the ankle, the lower leg, the knee, the hip, and the spine. Not only as they function individually, but as they relate to each other and to the opposite extremity.

In general, biomechanical-related pain results when there are variations in the average range of motion of these various joints and how one joint changes (compensates) in response to another/other joint/s. These variations can be the result of inherited traits, the result of previous injury or trauma, the result of compensation(s) from inadequate flexibility or training, or particular physical limitations.

The most common types of foot and lower extremity pain syndromes that may be caused (or exacerbated) by biomechanical-related factors include (but are not limited to):

Metatarsalgia; plantar fasciitis, heel spurs, stress fractures, nerve entrapments or neuromas, chondromalcia patella, ITB syndrome, runner's knee, trochanteric bursitis, and various bursitis', tendonitis', myositis', and neuritis'of the foot and lower extremities.

As you can see from the above information, biomechanical pain is a very non-descript entity with a loose association of conditions and maladies that can affect the foot and/or lower extremities. The biomechanics of how each of us ambulates, and ultimately performs our daily activities (whether that be just walking to work, or participating in a triathlon) is determined by many factors. Predominantly by what we inherit from our parents, but also by numerous environmental and physical factors.

For more information regarding the pain syndromes listed above, please visit the 'running injuries' common foot problems page.