What do Spencer Strider, Gerrit Cole, Tony Gonsolin, Eury Perez, Shane McClanahan and Jacob deGrom all have in common? These star pitchers have all suffered severe elbow injuries, causing them to miss at least half of the season, and for some, the entire year. Recently, Atlanta Braves star pitcher Spencer Strider underwent UCL surgery and is expected to miss the remainder of the season (MLB.com). Earlier this season, Gerrit Cole of the red-hot New York Yankees suffered an elbow injury before the season started that has caused him to miss the opening months of the year. So why exactly are so many pitchers sustaining severe elbow injuries? One of the answers lies in the progression of pitch velocity and arm strength over the course of MLB history.