Foot loading in normal and pathological walking

Perttunen, Jarmo Foot Loading in Normal and Pathological Walking Jyvaskyla: University of Jyvaskyla, 2002, 86 p. (Studies in Sport, Physical Education and Health, ISSN 0356-1070; 83) ISBN 951-39-1222-1 Finnish summary Diss. The present series of studies was designed to study the interaction between foot loading patterns and neuromusculoskeletal adaptation during normal and pathological walking. The behaviour of the foot was examined in healthy subjects and different groups of patients. In order to know how surgical intervention affected the ability to walk, foot loading patterns and neuromusculoskeletal function was studied before and after corrective surgery. Special emphasis was laid on understanding the benefits of corrective surgery. The test procedure for the Paromed-System used in the present study showed that it could be used accurately to examine the bilateral symmetry of foot loading during walking without any disturbance to the subject. The highest peak plantar pressures were found under the heel, the first metatarsal and the big toe in both the normal and patient groups. The results suggested that foot loading asymmetry did not increase at faster walking speeds in healthy subjects. However, patients with limb length discrepancy and patients recovering from tibial fracture had excessive foot loading asymmetries, which tended to become greater at fast walking speeds. The peak plantar pressures usually increased under the foot in the healthy subjects when walking speed increased while decreasing under the lateral forefoot. In contrast to this medial shift, bilateral comparison showed that the plantar pressures under the operated foot after free-flap reconstruction of the tibial fractures had shifted more to the lateral side of the forefoot. This lateralisation was a compensatory mechanism to reduce the loading on the ankle joint. The results from the triple jump showed that the high lateral forefoot pressure and maximal vertical ground reaction force in the braking phase and maximal horizontal ground reaction force in the anterior-posterior direction in the push-off phase were closely correlated to the length of the triple jump. In patients the foot loading and muscle strength symmetry improved notably during the follow-up after the reconstruction surgery to correct the limb length discrepancy. Because symmetry after the different surgical interventions was not completely restored, long rehabilitation period is needed after corrective surgery.