Getting indexed by Google scholar

[newwhy]

Often my Google Scholar alerts result in exactly what I think they will: scholarly articles published in academic journals. However, today I got this completely non-scholarly article https://www.t-nation.com/training/the-exact-reps-that-make-you-grow and I have no idea why Google Scholar is indexing this site. I've read up on how to get indexed by Google Scholar, and this website doesn't seem to have the necessary requirements. I'm curious for anyone whose clients or industry need to get indexed by Google Scholar, what has worked for you?