Single Leg Diagonal Hops

In 2000 (and on a few other occasions) I published and claimed copyright on this exercise description (bolding added now):

Single leg Diagonal hops:

Similar to lateral hops with a forward component. Jump diagonally forward – aim for maximal speed and minimal ground contact time.

I was conducting research and I came upon the following exercise in a publication copyright claimed by another 'author' at a subsequent date (bolding added):

Single leg Diagonal hops:

Similar to lateral hops with a forward component. Jump diagonally forward – aim for maximal speed and minimal ground contact time.

And I said to myself: “That looks familiar!” So I cross-referenced it and I said to myself: “Wow! No wonder that looked familiar!”

I noted that the use of this description was in the absence of credits or references to the origin or permission to use from the original author (myself), and that the 'author' claimed copyright....