FOOTWEAR AND FOOT ORTHOTIC EFFECTIVENESS RESEARCH - A NEW APPROACH

Measurement of calcaneal inversion and eversion during walking is limi ted when subjects wear shoes. The authors oi this study propose the us e of transverse tibial rotation as a viable alternative measurement wh en barefoot assessment is not possible. The purpose of this study, the refore, was to: 1) determine the relationship between transverse tibia l rotation and rearfoot motion during the stance phase of normal walki ng and 2) demonstrate the usefulness of measuring transverse tibial re lation when evaluating the effect of footwear and insole foot orthotic devices. Part 1 consisted of eight volunteers (live women, three men) whose rearfoot and transverse tibial motion was videotaped while they walked along a 12-m walkway. The results of this study showed that al though absolute values were not comparable, the two motion patterns ar e related to each other. The correlation between the mean rearfoot and tibial motion patterns of all 16 feet was r = .953. Part 2 investigat ed the effect of footwear and orthotics on transverse tibial rotation using two case presentations. A video camera war positioned in front o f each subject as they walked at a self-selected speed under various f ootwear or orthotic conditions. The results of the case studies reveal ed that footwear or foot orthotics decrease maximum tibial internal ro tation compared with barefoot walking. In addition, internal tibial ro tation velocity and acceleration were decreased by the use of shoes, a n accommodative orthosis, and an inflatable medial longitudinal arch s upport. A rigid orthotic produced a slight increase in transverse tibi al relation and a dramatic increase in transverse tibial acceleration. It is felt that measurement of transverse tibial rotation may prove u seful in evaluating footwear and orthotic effectiveness.