I just finished that book The Arm. If you enjoy baseball, get it.
Jeff Passan takes an excellent approach in focusing individual chapters on the disparate elements of approaches toward pitching; Japan, travel ball/Perfect Game USA, the Trevor Bauer/Driveline method. Additionally, he follows Todd Coffey and Daniel Hudson on the journey back from Tommy John surgery, with intimate access to each on the progression of the injury & its recovery.
Frank Jobe, Neal ElAttrache and even Tommy John Jr, who interestingly enough practices arm medicine with nonsurgical approach, are all frequent subjects. In short, MLB in 2014 finally made a real investment into a database of tracking pitcher activity both subjective and object of including injuries performance and biomechanics, and is building a tremendous database with the help of several esteemed medical institutes, that will hopefully arrive at some sort of conclusions for what type of habits are beneficial and which are detrimental to the state of starting pitching.
For now, Passan leaves us with just the facts and philosophies and some jaw-dropping stats about both the increase in velocity and the frequency and Tommy John surgery at all levels of baseball. Get the book. Read it. Awesome. Baseball (James Earl Jones voice).