Comparison of ground reaction forces and the amount of load introduced during crossover landing in people with flat foot and healthy individuals

Introduction: Investigating the risk factors during single crossover landing in people with flat foot complication is unknown. Therefore, the aim of the present study is to compare the ground reaction forces and the amount of load introduced during crossover landing in people with flat foot and healthy individuals.   Methods: The study method is descriptive-comparative. Twelve male subjects with low longitudinal arch (age = 24.67 ± 4.45; height= 176.12 ± 5.64; Weight= 765.62 ±11.2) and twenty-two matched healthy control subjects (age=23.47 ±5.63; height= 178.66 ± 3.87; Weight= 714.31 ±13.61) participated in this study. Based on the Arch Height Index (AHI), was divided into two healthy and healthy groups with flat feet. The ground reaction force was measured using a force plate (1000 Hz) during crossover-landing. Then, the kinetic indicators, including the peak of the ground reaction force and the time to reach them and the loading rate, were extracted by Vicon Nexus 1.8.5, Polygon 4.1.2 software. Data were analyzed with SPSS. 23. Results: People with flat feet have fewer vertical ground reaction force (FZ1,2,3) when crossover landing compared to healthy individuals (P <0.05). The time to reach the minimum vertical force of the action photo (valley) at the moment of contact of the toe with the ground (TFZ2) is faster in people with flat foot complication (P = 0.022). Conclusion: People with flat feet had less vertical force, less vertical reaction time, and faster reaction time than healthy people, and these factors were considered as a risk factor for increasing fracture of 1-3 metatarsal and ankle sprain. Therefore, it is recommended to teach strategies to prevent these risk factors in activity and rehabilitation.