somayeh Mehrlatifan - Department of Sports Biomechanics, Central Tehran Branch, Islamic Azad University, Tehran, Iran.
Ali Fatahi - Department of Sports Biomechanics, Faculty of Physical Education and Sports Science, Islamic Azad University of Central Tehran Branch, Tehran, Iran.
Davood Khezri - Department of Sports Biomechanics, Sport Sciences Research Institute, Tehran, Iran.

With the increase in the elderly population, the rate of their falls has also increased significantly and causes serious damage to the health of the elderly and society. Falling causes kinematic and kinetic changes in walking of the elderly. Ground reaction force (GRF) is often measured in gait and fall studies and analyzes and is considered as a criterion for walking evaluation. However, to date, no research has been done on the frequency content of GRF in elderly falls, which appears to be able to identify patterns leading to falls and injuries in the elderly. ۲۲ active elderly women aged ۶۵ to ۷۵ years volunteered for this research. They were grouped into two groups of ۱۱ people with and without a history of falling. The subjects walked along the designated path in the gate lab, the walking data was recorded with a force plate. The frequency content of GRF was extracted by fast Fourier transform (FFT) and MATLAB ۲۰۱۶ software.  Results: This study compared the frequency content of GRF during walking in elderly people with and without a history of falls. The results shown that F۹۹.۵% in the anterior-posterior direction and Fmed in the anterior-posterior direction in the fallen group were significantly higher than the non-fallen group. And it did not show any significant change in other trajectories and other variables. It was found that the fallers showed different frequency content. Performing GRF frequency content assessment has the potential to identify fall-related injuries in affected individuals.

elderly, Frequency content, Gait, Ground Reaction Force, Walking