Edit: Here's a link to the study from a better source. Also, this study unsurprisingly brought to you by the beef industry. https://www.sciencedirect.com/science/article/pii/S002231662... "This study was funded in part by The Beef Checkoff, Denver, USA,"
As an ex-vegetarian (who rarely eats meat now), I'd love to see more research into this and what's missing. Also, what needs to be done to supplement a vegan/vegetarian diet for exercise is pretty well known.
But this "study" of a small sample size confirms what has been pretty much completely and unambiguously known for decades. And it's meat industry funded. Nice.
However, it's pretty well known that animal protein is higher quality than vegatable protein (by the amino acid profile.) You can't just compare grams of protein on the back of the container.
So it wouldn't be all that surprising either. For me personally, I've tried whey protein powder and the vegan stuff (the good, expensive stuff.) I get better results on the whey. I also tried beef protein powder. It's disgusting, I don't know if the gains were any different from whey, but it's not worth it!