Russian Twist

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

Russian Twist

Lying on your back, knees bent to 90 degrees , feet flat on the floor. Partner should hold the feet in a fixed position. Slowly curl the body up to about 45 degrees from the floor. This is the set position. Now slowly turn to the left as far as possible, maintaining the 45-degree angle from the floor. Return to the set position and repeat to the right.

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):

Russian Twists :

Lying on your back, knees bent to 90 degrees , feet flat on the floor. Partner should hold the feet in a fixed position. Slowly curl the body up to about 45 degrees from the floor. This is the set position. Now slowly turn to the left as far as possible, maintaining the 45-degree angle from the floor. Return to the set position and repeat to the right.

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

And I came upon this description another five more times by the same 'author' in different publications.

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....