it IS racism to say "all *insert race* people are worthless"
it is not racist to say something based on fact "black people are better at running while white people are better swimmers" (as proven by the olympics)
It's the belief of people being inferior or superior solely based on their skin color. Really its not that hard to understand, but people keep peddling the misinformation that it must include prejudice + power and have forcibly trying to rewrite it as such. The prejudice + power is usually used to hide ones own racism. Usually anyone that peddles the prejudice + power are anti-white extremist or mistakenly belief that their own race, any color, is inferior.
Since it's likely that everyone has experienced racism by the time they read this I'm sure no example would be needed.