"Chicks dig the long ball" - Pitcher Greg Maddux of the Atlanta Braves in a TV commercial circa 2001
Although many fans forget, before the debacle that was the 2002 All-Star game in Milwaukee, both Sammy Sosa of the Chicago Cubs and Jason Giambi of the Bronx Bombers put on a show in the Home Run Derby contest that should serve as a wakeup call regarding that which "chicks dig".
As Sosa was belting 12 homeruns in the semifinal, five of which traveled over 500 feet (I presume without a corked bat although "corking" and other modifications generally do not increase distance but instead serve to lighten a bat making it easier to get it through the hitting zone) I was reminded that the longest homerun hit in an actual game traveled somewhere between 530 and 570 feet (officially 565 feet, Mickey Mantle off of Chuck Stobbs in 1953 although there has been much debate on the topic). However, as prodigious as those blasts were (Mark McGwire had put on a similar show at Fenway Park at the 1999 All Star game), I was equally interested in the incredulity expressed by pitcher Curt Schilling of the Arizona Diamondbacks, who was assisting with the broadcast, as Sosa would seemingly hit a ball off the end of the bat and to the opposite field that would end up some 430 feet from the plate. In one telling remark, Schilling noted that he couldn’t trust the way the ball sounded off the bat anymore, since in many instances he would turn around and watch the ball carom off the wall or fall lightly into the stands.
All of this made me think about some recent statistics that I’d heard and which I’ve now updated.
So what is reason for all of this power? As Ted Williams famously said, "hitting a baseball is the hardest thing to do in sports". Well, it wasn't as hard for him as for the rest of us but I still believe him. Recently, a scientific article titled How to hit home runs: Optimum baseball bat swing parameters for maximum range trajectories was published that throws some light on the subject and which, incidentally, came to some conclusions that differed from those found in the most popular work on the subject Robert K. Adair's The Physics of Baseball, first published in 1990.
Although I'm no physicist I found the following statements and conclusions in the paper interesting:
Embedded in these conclusions is the one that I think really matters when discussing the increased frequency of homeruns over the last decade. Increasing bat speed increases distance more than any other factor when swinging at a pitched ball. The models used by Adair and the authors of the paper use an average bat speed of around 70mph. However, I would speculate that the increase in weightlifting at the professional level anyway and both legal and illegal supplements over the last 10 years has increased the speed at which power hitters swing the bat and therefore increased the range of their hits proportionally. As a result, hitters have more room for error which manifests itself in at least 2 ways: 1) they can drive balls even when not hitting the "sweet spot" as Schilling observed in his comment regarding the sound of the bat, and 2) they can wait longer and still drive the ball to the opposite field since they can so quickly bring the bat to a high velocity (as a Cub fan observing Sammy Sosa during this period I can testify that the increase in his power was more pronounced to center and right field than to left, where even before he bulked up he could hit a homerun on a well hit ball).
While I view this as the primary factor in the increase in homeruns, I'm not discounting the other popular explanations that include livlier balls, smaller ballparks, and the decrease in confrontational pitching strategies including hitters wearing armour (Bonds) and umpires protecting hitters. All of these have likely had an effect, but I'm arguing that an increase in bat speed is the factor that carries more weight.
One may ask, so if baseball players are so much stronger, then why are pitchers not throwing the ball 110 mph? Historically, the pitchers that threw the hardest probably topped out at around 100mph as they continue to do today. Walter Johnson, Bob Feller, Nolan Ryan, and now Billy Wagner all threw in the 99-102 mph range at their fastest.
In short, I don't think pitchers have seen or will see a proportional improvement in their velocities because, to borrow a phrase from the late Harvard professor and baseball fan Stephen J. Gould in his essay "Why No One Hits .400 Any More" as republished in his book Triumph and Tragedy in Mudville , they as a group were already approaching the "outer limits of human capacity". Since pitching requires a more complex interaction of muscles than hitting, pitchers have always primarily trained by throwing the baseball. And so it's not suprising that some have been able to maximize their potential and get very close to the right wall of human ability for throwing a baseball for velocity. As a result, there is very little if any improvement to be had by better training regimes and even supplements. It should be stressed that this applies not to individuals but for advancing the group as a whole since certainly the entire group has moved closer to that wall as more pitchers take advantage of better training techniques. Think of a bell curve with a decreasing standard deviation and an increasing mean meandering down the x-axis towards a barrier (consequently, this answers the question of why, for students of baseball, the mythical Sidd Fynch throwing over 105 mph was immediately recognizable as an April Fool's joke). For hitters then, as a group they started farther from that right wall since there existed the belief that weight training was counter productive to baseball, and so by taking advantage of increased strength, they are inching their way towards their own right wall.