Research on the Impact of Running Gait Against Lower Extremity Running Injuries of Young Middle and Long Distance Athletes

Background: The causation between biomechanics of running gait and running injuries. At present, existing research results are contradictory. Objective: To further define the impact of gait biomechanics against running injuries and provide basis for injury prevention. Methods: Eighteen healthy middle and long distance athletes were selected to conduct biomechanical gait test under medium speed running by using Qualisys motion capture and 3D tracking system, Kistler force plate and Laser Velocimeter. After the test, collect a year of the running injury data and divide the athletes into a health group and a injured group. Compare the gait spatio-temporal parameters, ground reaction force, joint angle of trunk and lower extremity, and joint power of lower extremity of the two groups. Results: The difference between the health group and the injured group in gait spatio-temporal parameters and ground reaction force under moderate speed running is not statistically significant (P>0.05). Joint angle: the maximum extension angle of the trunk of the injured group was significantly greater than that of the healthy group (P<0.05), while the maximum flexion angle of the trunk was significantly less than that of the healthy group (P<0.05); The maximum right bending angle of the injured group was significantly smaller than that of the healthy group (P<0.05). The hip adduction angle during striking, the maximum hip adduction angle and the ankle varus angle during leaving the ground in the injured group were significantly lower than those in the healthy group (P<0.05); The internal rotation angle of ankle joint during striking in the injured group was significantly smaller than that in the healthy group (P<0.05), and the angle of lateral rotation of ankle joint off the ground was significantly greater than that in the healthy group (P<0.05). Joint power: The maximum hip joint extension power of the injured group was significantly lower than that of the healthy group (P<0.05), while the maximum knee joint abduction power was significantly higher than that of the healthy group (P<0.01). Conclusions: Compared with the healthy group, the injured group has a greater degree of trunk lean back, which may adversely affect the effect of pushing off and stretching. On the other hand, it may also lead to abnormal knee joint stress, which is closely related to knee joint injury. It also suggests that there may be imbalance of muscle strength in the front and back of the trunk, which may affect the trunk control. In the support stage of medium speed running, the injured athletes showed that their trunk bent to the opposite side of the support leg, landed at a small hip adduction angle and ankle pronation angle, and showed a large ankle external rotation angle. This gait makes it perform smaller hip joint extension power and larger maximum knee joint abduction power, which is not conducive to the full use of hip joint abductor muscles to generate propulsion, and increases the work done by the tissue structure around the knee joint to prevent excessive adduction, which is not conducive to the long-term maintenance of the stability of the frontal plane of the knee joint, and increases the risk of injury to the lateral tissue structure of the knee joint. Suggestions: Based on the above findings, it is recommended that athletes in the injuried group should focus on enhancing the functional exercise of the knee joint and the muscles around the pelvis, improving the dynamic stability of the frontal plane of the knee joint and trunk control, and enhancing the working ability of the hip extension muscle groups.