Definition of Lost a Step

What does the term "lost a step" mean in the world of sports? What is meant by "losing a step"?

In sports, "losing a step" occurs when an athlete noticeably slows down, usually due to injury or older age.

For instance - let's take a Wide Receiver in the NFL.

During their prime (mid to late 20s), they were considered to be one of the fastest wide receivers in the league, making them virtually impossible to defend.

As they got older (mid 30s), they were said to have "lost a step" as they were getting older and wearing down from numerous injuries suffered over the course of their careers. This makes them easier to defend and less valuable to their team.

In the regular world, "losing a step" often translates over to the business world. As people get older, they sometimes are said to have "lost a step", as they are perceived as being a bit slower and not quite as sharp as they used to be.