Why is the background blur effect so strong in sports photography?

There are three elements for background blur. First, the telephoto range. You cannot get close when shooting sports, so you must use telephoto. Second, large aperture. A good lens has a constant wide aperture. Third, the distance between the subject and the background. A lens only needs to have a large aperture or a telephoto length to easily blur the background. It’s not just that the background blur effect is strong in sports photography, it’s all about the lens.