THE BIOMECHANICAL CORRECTION OF DISMETRY AND PARAMORPHISM IN CYCLING

Abstract

Cycling is an aerobic cyclic sport which favours the articular movement of the lower limbs being the body weight distributed on five points (hands, saddle, pedals). Therefore orthopaedists and physiotherapists suggest it for the re-education of patients affected by trauma or after surgery. This sport is recommended for those sportsmen, who should better not practice other gravitational sports being affected by dismetries, hypotrophics and paramorphisms of the inferior limbs or of the spine. In cycling the shift of the muscular energy produced by the kinetic chain is done by the foot wrapped in a shoe and by the pedal which makes the pedal crank turn and so moves the vehicle in the space. It is evident that the joining point between foot, shoe and pedal and the working angles of the various body segments are fundamental for the biomechanical performance of the pedal push (transformation of the muscles' contraction energy in moving of the vehicle). Today use of shoes in synthetic material and pedals with rapid release is very widespread. The shoe's stiff sole is blocked on the pedal and does not allow the necessary adjustments in case of paramorphisms of the foot or of the inferior limb. In order to overcome the problems of the knee's position (dynamic knock-knee) or of the foot (flat, hollow or splay-foot) shims of 0,6-1mm. are used. Supinator wedges are put inside of the shoes between the sole and the heel. Subjectively the cyclists affected by flat foot, splay-foot or hollow foot of 1st or 2nd grade have tho sensation of a better support of the foot's sole and a reduction of the dynamic knock-knee. The muscular diemetries and hypomorphisms of the inferior limbs and the consequent asymmetries of the rachis are caused by congenital or acquired diseases. The patients with these problems who want to practice this sport need special devices to compensate the dynamic defects of the pedal push. In the described cases different techniques are applied in order to improve the muscles efficiency and to avoid pathologies deriving from a wrong position. The adopted techniques in the various cases are use of the pedal cranks of the different lengths. shims, differentiation of the bilateral heels, supinator wedges, supporting insoles and plantar arch.