The video is poor quality, nearly 100 years old but it is fascinating to watch Walter Johnson's motion especially the last part of the video showing his game speed motion. Watch his back leg, it never comes off the pitching rubber! I have never seen anyone pitch like that but according to history Johnson pitched 21 seasons and never had a significant arm injury and was absolutely the best pitcher of his era and possibly of all time. You would think someone would try to emulate his motion, but I don't believe I've ever seen anyone do it. Even great side-armers like Kent Tekulve brought their back leg through after the pitch and they throw slow. Johnson was a pure fastball pitcher.