Athletics is a broad category. Blacks do not dominate all areas of athletics. All the best olympic weight lifters are eastern european or nordic. All sports positions that require higher IQ are also white positions.

There are two additional factors to consider.

Factor One: white civilization:

There would be near zero blacks in high level athletics if they weren't living in white countries, going to white schools, benefiting from white medicine, absorbing white nutrition, and especially being coached and trained by whites using complicated training protocols (again designed by whites). Under a truly equal playing field blacks would struggle to compete in most sports with an exception to distant running.

Factor Two: white sports vs black sports.

Since whites have been marginalized by cultural Marxism and critical theory there's an exodus from mainstream sports. Many young white men and women have sought shelter from blacks in what you could call 'white sports'. Sports that require more gear and more barriers to entry are getting the bulk of white athletes. Lacrosse, hockey, wrestling, winter sports, swimming, outdoor sports (ultra marathon, etc), niche track and field, and several others are dominated by whites. The traditional argument is that black people are poor and that's why they don't dominate these fields. I'm not so sure that's the case. Many whites would happily play football or basketball. Many still play baseball, but they are constantly driven out of those sports because being around black athletes causes negro fatigue and often gets you in trouble in some way. In middle school or early high school most white athletes say fuck it and choose academics or niche sports simply so they don't have to deal with blacks. Coaches also repeatedly make exceptions for black athletes. Academics, behavior standards, and even rules of the game are bent to try to help black athletes advance.