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Biomechanics and Sports

BY John Vonhof, author of
Fixing Your Feet: Prevention and Treatments for Athletes


any athletes who have participated in sports have learned firsthand how one minor problem can be magnified over time and eventually have major consequences. Typically this happens when a blister affects the gait or foot pain from a heel spur or plantar fasciitis throws off balance and stance, or stressed or weakened muscles cause an imbalance in the body's mechanics.


Biomechanics is the study of the mechanics of a living body, especially of the forces exerted by muscles and gravity on the skeletal structure. The foot, which includes everything below the ankle, is a complicated but amazing engineering marvel. With an intricate biomechanical composition of 26 bones each, together they account for almost one-quarter the total number of bones in the entire body. There are 33 joints to make the feet flexible. About 20 muscles manage control of the foot's movements. Tendons stretch like rubber bands between the bones and muscles so that when a muscle contracts, the tendon pulls the bone. Each foot contains more than 100 ligaments that connect bone to bone and cartilage to bone and hold the whole structure together. Nerve endings make the feet sensitive. With each step you walk or run, your feet are subjected to a force of two to three times your body weight, which makes the feet prone to injury.

The big toe, commonly called the great toe, helps to maintain balance while the little toes function like a springboard. The three inner metatarsal bones provide rigid support while the two outer metatarsal bones, one on each side of the foot, move to adapt to uneven surfaces.

The transverse arch and the longitudinal arches support each foot. The transverse arch runs from side-to-side just back from the ball of the foot and is the major weight-bearing arch of the foot. The medial longitudinal arch runs the length of the instep, giving spring to the gait, flattening while standing or running and shortening when you sit or lie down. The lateral longitudinal arch runs on the outside of the foot. Both longitudinal arches function in absorbing shock loads and balancing the body. These three arches of the foot are referred to singularly as the foot's arch.


The body lines up over the foot and when the foot goes out of alignment, the ankle, knee, pelvis, and back may all follow. Analyzing the way we stand, walk, and run helps a podiatrist or orthopedist determine whether we have a mechanical misalignment and how it can be corrected. If you have nagging problems one of these specialists could help by evaluating your walking and running gait.

An example of biomechanics is how the foot's arch works. A low arch, or flat foot, typically occurs when the foot is excessively pronated, turning it inward. A high arch supinates the foot, rolling it outward. Both of these structural variations can cause knee, hip, and back pain. When one arch flattens more than the other arch, that inner ankle moves closer to the ground. That hip then rotates downward and backward causing a shortening of that leg during walking and running. The pelvis and back both tilt lower on the shortened leg side and the back bends sideways. The opposite leg, which is now longer, is moved outward towards the side that puts added stress on its ankle, knee, and hip. The shoulder on that side then drops towards the dropped hip. All of these are compensations as the body adapts. Muscles, tendons, ligaments and joints are stretched to their limit. The body is out of alignment. This can also happen from other body system failures. The shoulders, arms, back, abs, quads and glutes all play a major role in alignment and support. Remember how your gait changes when your quads lock up or your back is strained?

The stresses on our bodies can result in inflammation, often the cause of foot pain. Walking or running on unbalanced and uneven feet can result in fatigue. Fatigue gives way to spasms that may cause a shift in the shape of our feet. Corns, calluses, bunions, spurs, and neuromas may develop when joints are out of alignment. So, what does all this mean as we train and race?


Well, maybe not everything but close to it! As long as you have good form, whether running, hiking, paddling, or biking, you stand a better than average chance of not injuring yourself due to a biomechanical problem. But let foot pain or muscle imbalances cause you lean to the side, or weak abs cause you lean forward, or tired arms cause you to drop your shoulders, or spent quads cramp up, and your body is tossed out of alignment. This will ultimately work its way down to your feet and as they will have to work harder to give the support your body craves. It will become a viscous circle affecting your form.


The best bet to keep yourself healthy is to train wisely, whatever the discipline. Make sure your shoes are not worn down-replace them before they lose their support and cushion. Wear good insoles to balance the foot and provide good heel and arch support and alignment. Strengthen the ankles and knees with specific exercises. Do upper body exercises to strength your abs, back and shoulders. Work your arms so they can help maintain balance and proper form. Learn how to tape a sprained ankle or turned knee. Condition yourself in incremental stages, without huge jumps in mileage or extremes. Train with the gear you will use in an actual race or event-to condition the body and muscles. When hiking use hiking poles for support and to help the knees. Learn your body's weak links and find exercises to strengthen those muscles and joints.

Every one of us, at one time or another, can fall victim to biomechanical problems as we play our sports for extended periods. Train smart, and walk and run smart, and you can stay healthy, starting with your feet.

John Vonhof, author of Fixing Your Feet: Prevention and Treatments for Athletes, Second Edition
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NOTE: The purpose of this newsletter is to expand thinking about fitness as an informational source for readers, and is not medical advice. Before attempting the Synergy Fitness program, the Sprint 8 Workout, or any high-intensity exercise program, consult your physician. This is not just a liability warning; it's wise to have a baseline medical exam before beginning a fitness program. Make your physician a partner in your fitness improvement plan.


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