Single Leg Jump Squats

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

Single Leg Jump Squats:

Stand on one leg facing a small box or bench. Jump up on top of the box - taking off and landing on the same leg. Use the arms to assist in the jump and emphasize speed. Perform all the reps on one side before changing sides. Perform the non-dominant side first.

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 Jump Squats:

Stand on one leg facing a small box or bench. Jump up on top of the box - taking off and landing on the same leg. Use the arms to assist in the jump and emphasize speed. Perform all the reps on one side before changing sides. Perform the non-dominant side first.

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....