Biomechanics is a scientific physics-based recognition of how the body works during rest and motion. It provides a method of analysing the way a person runs, walks and sits, plus an intimate understanding of the altering bone, joint and muscle positions during these activities.
The dynamic musculoskeletal functions of the body are achieved through complex interactions between the skeleton, muscles, tendons, ligaments and nerves. The skeleton provides the supporting structure. For example, when we move around, whether it is running, walking or just getting up from a seated position, the 26 bones in each of our feet are expected to provide a stable platform, evenly distributing body weight. The muscles initiate movements that may be intentional or subconscious, depending on the way the nerves are communicating with the muscles and ligaments.
Imperfections to our supporting skeleton may be passed on from previous to future generations. They may also result from injuries due to acute accidents or long-term degenerative changes caused by diseases such as arthritis. If our supporting structure is compromised, our posture must compensate so that we do not fall over.
As it is the role of muscles to stabilise and move joints, our muscles will be directly affected by skeletal problems. They will need to become stronger or longer than if the skeleton were working in a more efficient way. Conditions such as shin splints, plantar fasciitis, pes anserinus bursitis, hamstring strains and piriformis syndrome occur when skeletal imperfections place a strain on our muscles.
Joints will stiffen if they are repetitively required to work in unstable positions, for example when you have a bunion or sore ankle. The stiffening is caused by the ligaments that make up the joint capsule surrounding the joint. When these ligaments become compromised, it directly affects your balance as the body’s proprioception (ability to right itself) becomes impaired. This may, in turn, lead to the skeleton becoming compromised.
Treatment of these conditions is often dramatically accelerated if small structural imperfections or skeletal imbalances are recognised and accommodated or balanced out. For example, in the case of a person with painful arthritic knees and bunions, treatment of the knees will be dramatically enhanced if the structural reason for development of the bunions is balanced out. Biomechanically, the bunions inhibit the external rotation of the knee during push-off, creating a misalignment of the knee and patella tracking.
Biomechanical treatments including orthoses (more commonly known as orthotics) can effortlessly balance out a range of muscular or structural compensations within the legs. When any structural contribution to the compromised site is reduced, then a program of static and dynamic rehabilitation should be undertaken to improve the stability and function of the painful sites.
Orthotics are defined as any devices that can assist a limb or body part. They can be as simple and short-term as strapping an ankle or as complex and long-term as functional orthotics. Orthotics may be: accommodative, helping to redistribute weight from painful areas; corrective, for balancing out structural imperfections; or functional, helping to improve the mechanical advantage or power of a specific structure such as a muscle or joint.
In the case of rigid orthotics, a variety of materials can be used including plastics, carbon fibre, fibreglass and even Kevlar. Once the corrective or functional aspect of the orthosis is decided upon, accommodative or protective materials may be added to cushion sensitive areas. In any event, foot orthotics should be very comfortable, not cause irritation and enhance the limb without compromising other structures.