But it does allow us to examine Johnson's pitching mechanics. He has no scapular load to speak of, does not have a particularly powerful arm action
(NOT be be confused with arm speed), throws with a relatively stiff lower half, and his stride is almost non-existent. Therefore, we must take into account what things he DOES show. Relative to the rest of his mechanics, Johnson shows remarkable arm speed
. He also shows very good (unusually good considering the time period) hip/shoulder seperation; that is to say, his hips are facing home plate far before his shoulders start to turn. He also has an aggressive follow-through. Although I have extreme difficulty buying something in the high 90's/low 100's from examining the biomechanical aspect of his delivery, I can bring myself to believe that if he had a very significant amount of "fast twitch" muscle fiber in his right arm, he could have been throwing in the low 90's...
Then there's this: until the mid 1920's to early 1930's, pitching mechanics can't really be described as "modern" or really capable of producing as much speed from a biomechanical standpoint in terms of the arm actions, strides, leg drives, and (to an admittedly much-lesser extent) even the hip/shoulder seperations. That's why you all of a sudden start seeing so many "unbelievable, never-before-seen-speed" type pitchers from around that era. Dizzy Dean, Dazzy Vance, Lefty Grove...all these guys threw with reasonably modern mechanics compared to the Dead Ballers and all were quickly proclaimed to be the fastest pitcher in baseball the moment they showed up.