Relationship between kinematic parameters of the lower limb and maximum ground reaction force during jumping and one-legged landing

Background: Anterior cruciate ligament injury is one of the most common injuries of the knee joint and prevention of this injury is of great importance(1). Considering that ground reaction forces are one of the load factors on the anterior cruciate ligament, Despite much research in this field to prevent ACL injury, the prevalence of this injury is still high(2). For example, previous studies have shown that increasing the valgus angle of the knee(3,4), decreasing the flexion angle of the knee(5), and decreasing the flexion angle of the hip(6,7) during landing cause more damage to the anterior cruciate ligament. In fact, the common movement pattern in non-contact ACL injuries includes a decrease in knee flexion, hip flexion, and trunk flexion with an increase in knee valgus and tibial rotation(4). Studies have shown that the anterior shear forces are the main mechanism of load on the anterior cruciate ligament(8). Ground reaction force is an important kinetic parameter in the lower extremities. The ground reaction force during sports activities affects the magnitude of the anterior tibial shear force by changing the flexion-extension torques of the knee, which must be balanced with the quadriceps and hamstrings. Landing Error scoring system test is a very inexpensive tools that calculates the jump-landing technique error in a range of visible items in human movement. Given that the LESS is a test to predict anterior cruciate ligament injury, and on the other hand, the ground reaction forces that enter the knee joint as a result of landing after a jump can cause anterior cruciate ligament injury for That the results of the landing error scoring test are to predict anterior cruciate ligament injury, given that it has been proven the ground reaction forces on the knee cause anterior cruciate ligament injury to be more confident in the results of LESS test to Predict Anterior Cruciate Ligament Injury and how much the implementation of the LESS test based on ground reaction forces can help the athlete community in identifying individuals prone to anterior cruciate ligament injury. therefore, the purpose of this study The relationship between the kinematic parameters of the lower limb and the maximum ground reaction force during the jumping and one legged landing in football players. Methods: The present study was a type of correlational research and sampling method was selected and available. The statistical population of this study included all male football players in Chaharmahal and Bakhtiari province with the age range of 17 to 23 years. Among this statistical population, based on the LESS test, the reliability was reported be good to excellent. A total of 21 subjects were selected and the criteria for exclusion from the lower extremity injury test (including knee, ankle, etc.) and any surgery in the lower extremity. The test procedure for the landing error score test was that people jumped from a 30 cm platform and landed in front of the platform at a distance of approximately 50% of their height, and then immediately performed a maximum vertical jump. 21 athletes (age:19.6±0.9 years, weight: 69.5± 6.3 kg, height 176.24± 3.44 cm) that 11 people with a high score from the LESS test is susceptible to the ACL injuries and 10 people with low scores were selected from the LESS test who were not susceptible to ACL injury. Before taking the test, each of the subjects was explained how to take the test and the project, and they all signed the consent form to take the test. To collect the maximum ground force information from a three-axis force plate (Kistler model 5*60*50 cm, made in Switzerland) which was embedded in the laboratory floor, to record and measure the ground reaction forces entered by the lower band and detect the first foot contact was used. Ground reaction force information was recorded by a force plate with a sampling frequency of 200 Hz(9). To perform the single-leg jump-landing test, the subject stood on two legs and performed a maximum vertical jump and landed on the dominant leg. Ground reaction force data Were registered by QTM software and These data were then transferred to Moka software (three-dimensional analysis of kinetic and kinematic motion) and the data were extracted by this software and MATLAB software was used to analyze the force data. In order to filter the raw data, the low-pass Butterworth technique with a shear frequency of 20 was used, which was determined using the residual analysis technique(10). All data were analyzed using SPSS software version 22. Shapiro-Wilk test was used to investigate the data distribution and Pearson correlation test was used to investigate the relationship between the maximum ground reaction force and the landing error score. Also, hypothesis testing was performed at a significance level of 95%. Result: The results showed that there was a significant relationship between knee flexion, trunk flexion and plantar flexion with ground vertical reaction force and also between knee flexion and trunk flexion and plantar flexion with posterior anterior ground reaction force (p <0.05). There is a significant relationship between all cases of lower limb movement, thatchr('39')s mean knee flexion, trunk flexion, knee valgus, plantar flexion of the foot and the position of the foot (outward or inward foot) with the internal-external force of the ground reaction (p<0.05). That is, by reducing the knee flexion and reducing the trunk flexion and reducing the plantar flexion of the foot (landing at the first moment of impact with the sole of the foot or with the heel), the vertical force of the ground reaction on the knee increases. Also, by reducing the knee flexion and reducing the trunk flexion and reducing the plantar flexion of the foot, the anterior-posterior force of the ground reaction applied to the knee also increases. By increasing the knee flexion, decreasing the trunk flexion, increasing the knee valgus, increasing the plantar flexion of the foot and increasing the position of the foot, the internal-external force of the ground reaction to the knee increases. As can be seen in the table, most correlation with the external internal reaction force of the knee is the valgus of the knee, which increases with increasing valgus of the knee. Conclusion: According to the results it can be concluded that just as the ground reaction force is one of the causes of anterior cruciate ligament injury and has a significant relationship with the landing error score, so the landing error score can predict the anterior cruciate ligament injury.