Background:Walking is one the common daily activities. With the beginning of middle age, weakness in the lower limb muscles can reduce the ability to walk. The use of foot orthoses reduce the load on the limbs and supports the joints during walking. The purpose of the present study was to investigate the acute effect of foot orthoses on the frequency spectrum of ground reaction forces during walking in the older adults. Methods: In this semi-experimental and laboratory study, 21 elderly (15 females and 6 males) with a mean height of 164.19±4.26 centimeters and weight of 80.04±3.50 kg, and age of 66.00±3.50 years were volunteered to participate in the study. The walking trials were done during three conditions including walking without foot orthoses, walking with small and large textured orthoses. The Bertec force plate (made in USA) with dimensions of 40 * 60 cm was used to record ground reaction forces. Results: The results of this study did not show any significant differences between walking without foot orthoses, walking with small and large textured foot orthoses for frequency of 99.5%, median frequency, frequency band and number of essential harmonics (P>0.05). However, the comfort level during wearing of large texture insole condition significantly increased compared to other conditions (P<0.05). Conclusion: The textured foot orthoses do not affect the frequency spectrum of ground reaction forces; however, it improves the comfort of the individual while walking.

Background: Genu valgum is a postural malalignment in the knee joint. This malalignment is accompanied by altered mechanical forces in the tibiofemoral and patellofemoral joints. The purpose of this study was to investigate the effect of using a graded knee brace in two angles of 60 and 30 degrees on the frequency spectrum of ground reaction forces in individuals with genu valgum during landing. Methods: The present study was semi-experimental. Twenty non-athlete male students with genu valgus (age range: 20-30 years) were volunteered to participate in the study. The landing task was done during three conditions including without a knee brace, with a brace at two 30 and 60 degrees of flexion from a height of equal to 30 cm. Bertec force plate was used to record ground reaction forces. Fourier transform was used to calculate ground reaction force-frequency content during both landing conditions with and without a knee brace. Results: The results of this study showed a significant reduction in the frequency content with a power of 99.5% in the mediolateral direction (P=0.02; high effect size) and vertical direction (P=0.075; high effect effect) during landing with a knee brace at 60 degrees of flexion angle compared with without knee brace condition. Also, the median frequency component in the mediolateral direction (P=0.019; low effect size) and in the anterior-posterior direction (P=0.019; high effect effect) showed a significant decrease during wearing a knee brace compared with without it. Conclusion: Regarding the decreasing of median frequency after using the knee brace, it might be effective in the reduction of injury rate in individuals with genu valgum. However, further study warranted to better establish this issue.

Background and Objectives: Knee joint, like other joints in the body, is affected by defects, injuries and diseases.Genu valgum is one of the most common lower limb complications. The purpose of the present study was to determine the effects of corrective exercises using Thera-Band on components of ground reaction force in boy students with genu valgum during running. Materials and Methods:The present study was a clinical trial. 24 male students (20-30 years old) were randomly divided into control and experimental groups. The present study was conducted at University of Mohaghegh Ardabili Health and Wellness Center in 2019. Corrective exercises were performed for 8 weeks using Thera-band for the experimental group. The control group did not receive any treatment intervention during this period. The ground reaction forces were recorded by a force plate. Data were analyzed using repeated measures ANOVA. Results:The results of this study showed a significant difference in the time to peak in the vertical direction during the push off phase of the experimental group (5.17%) (p=0.030, d=0.589). In the experimental group, the other components of ground reaction forces did not demonstrate any significant effect during post-test than that in the pretest (p>0.05). Conclusion:The selected corrective exercises using the Thera-band were able to increase the time to peak of the vertical force during the push off phase during the post-test compared to the pre-test. This increase was probably due to the longer contact of foot with the surface, which reduces the amount of force applied to the foot.

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