In sports training, it is very common for athletes to get injured. Generally, athletes use lower limbs more. Therefore, knee joints are easily injured. After knee joint injury, it will affect the athlete's athletic ability and performance, and cause certain damage to the athlete's physical health, and even affect the athlete's sports career. In order to reduce the injury of the athlete's knee joint and prolong the athlete's sports career, it is necessary to find the reason and find the prevention method. This article mainly takes 30 athletes as the research object. According to the results of the research, we find out the causes of knee joint sports injuries and do a good job in preventing knee joint sports losses.

Affected by the COVID-19, China's 2020 spring courses have been postponed, and then switched to online courses. In the reform of physical education teaching, many scholars have been committed to the implementation of online teaching of physical education courses. Therefore, during the epidemic, studying the influence factors of online teaching of physical education courses on teachers and students will help promote the teaching reform of physical education courses. Enrich the teaching system of teachers and improve students' learning enthusiasm. According to the statistics of the online questionnaires of physical education teachers and students, both teachers and students have an understanding of online courses, and both accept the online teaching mode, but due to the particularity of physical education courses and the teaching system of sports online courses are not yet mature and limited Sex, the online teaching of physical education courses did not have a significant positive impact. Therefore, teachers need to have a deep understanding of the online teaching system, enhance their own awareness of online teaching, promote the combination of online and offline, and ensure the quality of students' learning through rich teaching methods.