The Biomechanical Effects of Arch Support Inserts for Pes Cavus

• Main Authors: Li-Ru Chen, 陳麗如
• Other Authors: Sai-Wei Yang
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/40216472048824686361

碩士 === 國立陽明大學 === 復健科技輔具研究所 === 95 === Pes cavus is often obscured by people. It occurs in approximately 15% of the population. The etiologies include idiopathic, neuromuscular, and traumatic diseases. Almost twice the number of painful feet is because of pes cavus than pes planus. This kind of foot absorbs impact force poorly. People with cavoid feet have a greater risk of lower limb athletic injury. The findings of previous researches on biomechanical behaviors of pes cavus was inconsistent. Although insoles have been used for symptomatic pes cavus in practice for many years, few investigations focused on its biomechanical effects. This research aimed at the biomechanical behaviors of pes cavus and the changes brought by insoles. Eighteen to twenty-five years-old young adults were recruited. None of them suffered acute foot injuries in the past six weeks or had lower extremity surgeries or trauma. Subjects with inflammatory arthritis, diabetes, neuromuscular disorders, or congenital musculoskeletal defects were also excluded. All participants signed the informed consent. A standardized protocol of questionnaire and measurement, including characters of foot or lower back discomfort, foot callus location, tender point distribution, manual muscle power of ankle dorsiflexion, plantar flexion, and eversion, and range of motion of the foot and ankle, were performed before walking trial. Kinematic and kinetic variables of lower extremities on five conditions: barefoot, Kong-fu shoe, Kong-fu shoe with arch support insert, athletic shoe and athletic shoe with arch support insert, were collected via Novel Pedar-X system, AMTI force plate, RSscan plate, and Vicon motion analysis system. The arch support insert is made of polypropylene with 2.5-2.9mm arch height. The participants were allowed to practice a walk with self-selected, comfortable speed on the boardwalk in a period of 2 minutes. Five trials were recorded for every condition of each subject. Twenty-six young adults completed the study. Thirty-four feet were compatible with the criteria of idiopathic pes cavus, whose arch index are below 0.19. Forteen feet with AI between 0.21 and 0.25 were grouped as normal feet. Their gender, age, height, and body weight were matched. No significant difference of cadence and walk speed between these groups. Pes cavus has bigger plantar flexion angle during loading response but smaller dorsi-flexion angle during midstance period and late stance phase. The midfoot force difference and second peak vertical ground force of cavoid foot were smaller than those of normal foot. Peak plantar pressure and pressure-time integrals were higher for pes cavus at the forefoot and rearfoot region, but it could be decreased with arch support. The acceleration of center of gravity projection during early terminal stance period was obscured by athletic shoe. The arch support insert would add some motion control effect on the Kong-fu shoe and let the biomechanical behaviors of pes cavus trended to normal.