Human beings are unique in their ability to throw an object overhand with speed and accuracy. In a report for Harvard Medical School, Neil Roach explained that humans have developed their unique ability to throw objects overhand from a series of anatomical changes that were needed for humans to hunt and reach the top of the food chain. Our closest relative, the chimpanzee, typically throws underhand, but in the rare occasion they throw overhand, their speed and accuracy is no more powerful than that of an average Little League pitcher. The lowering and widening of the shoulders and the twisting of the humerus are the two notable anatomical changes that have enabled humans to use their shoulders like slingshots, hurling an object with great speed and accuracy.
The greatest display of this innate human ability to throw overhand is found on the baseball diamond. When watching a Major League Baseball game this season, tune into the radar gun that is displayed on the scoreboard. In 2013, the average fastball in the major leagues was 91.8 miles per hour. This figure has been trending upwards in the past decade due to increased emphasis on strengthening and conditioning programs amongst professional athletes. The average fastball might be just under 92 mph, but many big leaguers routinely throw fastballs that can hit triple digits on the radar gun. According to Dr. Glenn Fleisig, who studies the biomechanics of pitching at the American Sports Medicine Institute in Birmingham, Ala., the shoulder rotation in baseball pitching is the fastest motion of any joint in any athlete. At its peak speed, a major league pitcher’s arm rotates upwards of 8500 degrees per second. This means if that single instant of speed could be maintained, a pitcher’s arm would spin around 24 times in a second.
Although the human body has evolved to enable such a throwing motion, it simply cannot withstand the extreme torque necessary to throw a baseball at such tremendous speeds. Much of the stress is centered in the shoulder labrum — cartilage in the center of the shoulder joint—and the rotator cuff — a group of muscles and tendons that stabilize the shoulder — but the most vulnerable part of a pitcher’s arm is the elbow’s ulnar collateral ligament. By conducting research on cadavers, Dr. Fleisig has found that the amount of force needed to throw a baseball upwards of 100 mph is greater than the amount of force the UCL can withstand before tearing.
Human beings have become so effective at throwing baseballs that we are actually exceeding the physical limits of our unique anatomy. The rising trend in fastball velocity is being mirrored by the rising frequency of arm injuries, most notably injures to the UCL. The procedure to repair a torn UCL was first performed in 1974 by Dr. Frank Jobe on Los Angeles Dodgers pitcher Tommy John. The procedure now referred to as Tommy John surgery involves replacing the torn ligament with a tendon from elsewhere in the body. A report published last month in The American Journal of Sports Medicine looked at 216 major league pitchers who had the surgery between 1986-2012 and found that 83 percent of the pitchers returned to the major leagues.
At the beginning of the 2013 season, of the 360 pitchers who started the season, 124 shared the same scar on their elbows. Elbow injuries have always been common in baseball, and MLB teams have taken many steps to help alleviate the stress put on their pitchers. Every MLB team has their pitchers do various strengthening exercise to help build up the small muscles in the shoulder, and there has been intense scrutiny regarding the number of pitches a pitcher throws each outing and the number of days between each outing. Until the 1970s, MLB teams would use a four-man pitching rotation in which every starter would make between 35-40 starts per season. Since then, every team has switched to a five-man rotation where each starting pitcher starts about 30 games.
Despite the adjusted rotations, strengthening programs and extreme monitoring and caution of pitchers, UCL injuries are occurring at a higher rate this year than any other. By this date last year, eight pitchers at either the major or minor league level had undergone Tommy John surgery, and by this date in 2012, 12 pitchers had received the surgery. So far this season, 21 pitchers at the major or minor league level have had the operation, and four of the 21 had the surgery for the second time.
By the time a pitcher reaches the big leagues, however, the problem may already be out of their control. Of the 21 pitchers who have undergone Tommy John surgery this season, only one — Bruce Rondon of Venezuela — came from Latin America despite 24.2 percent of players on the Opening Day rosters of MLB teams hailing from Latin America. This has led people to call into question the American specialization of sports, and American youth baseball in particular.
The top high school pitchers routinely pitch year round, giving their arms no time to recover. And since the single most important metric in scouting an amateur pitcher is the velocity of their fastball, these hurlers spend almost every weekend throwing as hard as they can to improve their recruiting and draft prospects. In Latin America, however, the top prospects are usually signed as a 16-year old, allowing the players to grow into their velocity rather than throwing their arms out trying to impress scouts for a longer period of time. These players are being signed almost entirely on their potential to develop under the club’s tutelage, but American prospects are drafted more based on their present ability. While the model for signing prospects that Major League teams use in Latin America is not possible in the United States due to the school system, we must find a more sustainable method to promote and develop our youth talent. Endless youth tournaments and increased emphasis on radar gun readings will only diminish the chances of having an injury free professional baseball career.