Search

Background: Prosthetic foot is an essential element of lower limb prosthesis, which plays an important role in the amputee gait. There is a growing trend towards development of energy storing prosthetic feet considering the amputee needs during walking. Several researches have focused on kinetics and kinematics of energy storing feet, however little is known about the mechanical properties of these commercial feet. Purpose: Assess the mechanical properties of Flex-foot using its force-deformation curve and a linear elastic model. Materials and method: This was a case study in which gait of a healthy subject was analysed and maximum force of 800 N was defined as applied load on the prosthetic foot. Load-deformation test was performed on heel and forefoot regions of Flex-foot using a testing machine. A linear elastic behaviour was assumed, and thus the slope of the force-deformation curve was defined as the stiffness. Results: The linear elastic model was found relatively appropriate (R2 > 0.9). The stiffness in heel and forefoot was found to be 88.85 and 74.54 N/mm, respectively. Conclusion: The results of this study show that a linear elastic model could predict mechanical behaviour of this foot adequately. The higher stiffness in heel compared to forefoot is an indicator of greater storing capacity in this region.

Background: The flatfoot might be caused complications and pain within upper joints and also change distribution of plantar foot pressure in flatfoot patients. One of the current treatments for this problem is longitudinal arch support insole which might be used for decreasing the related complications of this disorder. This foot orthosis maybe help to improve the medial longitudinal arch and redistribute of foot plantar pressure. Purpose: Assessing the distribution of plantar foot pressures within flexible flatfoot patients and the effects of longitudinal arch support insole on distribution of plantar foot pressures were the aims of this study. Materials and method: This was a quasi-experimental study with participation of 12 young men with bilateral flexible flat foot (age: 18- 28). The plantar pressures measurement insole (Pedar) was used for measuring the foot plantar pressures as an instrument which it includes five different sizes of insoles with 99 sensors. Each trial included three direct walk ways (nine meters) with normal speed and 50 Hz. There were two types of tests with/without foot orthoses. Results: There was a significant decrease of plantar pressure in medial hindfoot and a significant increase of plantar pressure in midfoot foot by using the longitudinal arch support insole in contrast of without orthoses condition (with shoe). There was also an increasing contact area in the medial part of midfoot foot by using of foot orthosis in comparison of using the shoe only. Conclusion: The results of this study shows that the foot orthoses might be caused to transfer the pressures from other adjacent areas include hindfoot and forefoot to midfoot foot which support the previous studies. Also, significant decrease pressure in hindfoot by using the foot orthoses confirms that insole may help the foot to compensate the function of medial longitudinal arch.