I'd argue strongly against inverted W as any sort of causation, as would Mike Maddux, his brother Greg, Nolan Ryan, and Tom Seaver, all of whom have stated that it was exactly how they were taught to generate power, and how they did generate power over very long careers. With Mike, it's how he's taught pitching, and he's had extremely good rates of injury with the pitchers in his tutelage over the years. There could be some level of correlation, but I think part of the issue we have is that we're watching frame by frame on pitchers now and breaking down every second of a delivery. By all means, the lack of utilizing legs within delivery to generate velocity and movement rather than arms, the poor weight training still predicated on young pitchers in high school ranks (seriously most gymnastics coaches in high school understand weight lifting better than baseball coaches), and the over-emphasis of velocity over pitching skill has rapidly affected the health of arms.