Prior to comprehending the correlations between a catcher’s throwing motions and performance outcomes, it is necessary to discuss the reasoning for the throws made and elaborate on the elements that come into play when a ball is thrown.
Baseball Objectives and Measurements
Baseball is a competitive game between two teams whose main objective is to win by outscoring the opponent in total runs (Major League Baseball - Professional Baseball Playing Rules Committee). A regulation baseball diamond measures 90 feet (27.432 meters) from home plate to third base, 90 feet (27.432 meters) from home plate to first base, and 127 feet 3 3/8 inches (38.795 meters) from home plate to second base (Major League Baseball - Professional Baseball Playing Rules Committee).
Baseball – Offense
The offensive game in baseball consists of batters and base runners. Batters face pitchers with the goal of getting on base or simply scoring by hitting a homerun. There are four main methods of reaching the base paths: being walked (BB), hit-by-pitch (HBP), reach on error (ROE), bunting, or hitting the ball. Once base runners are present, the main objective is to increase the possibilities of reaching home and scoring. The chances of scoring are increased once runners advance into scoring position i.e. second or third base. Base runners are able to advance on the base paths when hitters behind them reach base on balls (BB), hit-by-pitch, recording a base hit, or sacrifice bunt or fly. Base runners themselves can also advance when the pitcher throws a wild pitch, a catcher has a pass ball, or the runner can steal a base. Base stealing in particular is often considered a vital aspect of offence in the game of baseball (Loughin &
Bargen, 2007). Having base runners allow the offense to steal runs and put pressure on the opposition (Scala, 2009). Base stealing is a commonly used strategy in baseball to advance runners into scoring position (Freeman, 2006).
Baseball – Defense
In order to defend against the offense, nine players take the field. Outfielders defend against any hit ball that gets past the infield. Infielders field any balls hit within their range or is in the vicinity of the bases when balls are thrown to the base to record an out. The battery consists of the pitcher and the catcher (National Alliance for Youth Sports & Bach, 2007). The pitcher begins each play by throwing the ball towards home plate with the objective of getting the batter out (National Alliance for Youth Sports & Bach, 2007). The catcher, commonly referred to the general of the baseball game, is able to see the entire field of play and is consistently involved in every play (Scala, 2009). It is the responsibility of the pitcher and catcher to keep runners close to the base, and a primary responsibility of the catcher to thwart would be base stealers by catching the pitched ball and quickly throw the ball towards the base being stolen in order to throw out the base runner (National Alliance for Youth Sports & Bach, 2007; Scala, 2009; Loughin & Bargen, 2007, LA84 Foundation, 2007). Catchers need to be quick and make fast and accurate throws to catch the base runner (Scala, 2009; Loughin &
Bargen, 2007).
Catcher throwing motions
Catchers are required to make the most throws during the course of a baseball game, with their throwing ability being highly valued by professional scouts (Fortenbaugh & Fleisig & Bolt, 2010). In order to throw out base runners attempting to steal second base, the catcher must accurately throw the ball roughly 40 meters in at least 2.0 seconds (Fortenbaugh & Fleisig, &
Bolt, 2010; Scala, 2009). The catcher begins each pitch in a deep, squatted position (Fortenbaugh
& Fleisig & Bolt, 2010). The catcher must then receive the pitched ball, rise from the squatted position, move the glove closer to the throwing hand, and smoothly and quickly transfer the ball from the glove to the throwing hand (Scala, 2009; National Alliance for Youth Sports & Bach, 2007; Plummer & Oliver, 2013). The catcher then rotates the hips and shoulder toward second base and begins the throwing motion (National Alliance for Youth Sports & Bach, 2007). In the ideal condition, a pitch out is used. In this scenario, the catcher catches the pitched ball at a nearly erect position’s chest height in the unimpeded batter’s box. This allows for an unobstructed throw to second base (Fortenbaugh, Fleisig, & Bolt, 2010).
Significant amount of research regarding throwing kinematics and kinetics has been conducted on pitchers (Urbin, Fleisig, Abebe, & Andrews, 2013; Fleisig, Bolt, Fortenbaugh, Wilk, & Andrews, 2011; Dun, Kingsley, Fleisig, Loftice, & Andrews, 2008; Hirashima, Yamane, Nakamura, & Ohtsuki, 2008; Keeley, Oliver, & Dougherty, 2012; Hirashima, Kadota, Sakurai, Kudo, & Ohtsuki, 2010). Similar to pitching, catchers too must rotate the trunk to face the intended target. The core muscles can be optimally sequenced in the kinetic chain with proper timing between the pelvis and trunk rotation (Urbin, Fleisig, Abebe, & Andrews, 2013).
Following the rotation of the trunk, the shoulder must externally rotate while flexing the elbow.
After reaching maximum shoulder external rotation, the shoulder must internally rotate and the
elbow extended with great acceleration in order to throw the ball (Plummer & Oliver, 2013). The phases of the throwing motion described previously can be can be seen in figure 2-1.
Fortenbaugh, Fleisig, and Bolt observed that the catcher’s throwing mechanics differ from other players in that shorter strides are taken as well as very little pelvis and trunk separation that is more commonly seen in pitching (Fortenbaugh, Fleisig, & Bolt, 2010). When the throwing distance was increased past the distance of the pitcher’s mound, it was observed that players relied more on greater pelvis angular velocity, trunk angular velocity, elbow flexion, and elbow extension velocity (Fleisig, Bolt, Fortenbaugh, Wilk, & Andrews, 2011). The greater distance also resulted in higher elbow and shoulder torques, as well as increased maximum shoulder external rotation angles (Fleisig, Bolt, Fortenbaugh, Wilk, & Andrews, 2011). The dissimilar throwing mechanics in comparison to pitching results in lower ball velocities by the catcher, however demonstrate virtually homogenous stress on the shoulder and elbow joints when analyzed with pitching and long-toss; the change in motion is perhaps due to the catcher’s need to quickly throw the ball to the target (Fortenbaugh, Fleisig, & Bolt, 2010).
Figure 2-1. Phases of the throwing motion.
Ball Velocity
Throwing velocity is imperative for pitchers and position players in the game of baseball (Escamilla, Fleisig, Yamashiro, Mikla, Dunning, Paulos, & Andrews, 2010; Escamilla, Ionno, DeMahy, Fleisig, Wilk, Yamashiro, Mikla, Paulos, & Andrews, 2012). The ability to throw the ball at a higher velocity could be improved via throwing mechanics or instituting strength and conditioning programs (Escamilla, Fleisig, Yamashiro, Mikla, Dunning, Paulos, & Andrews, 2010). Additionally, efficient throwing mechanics could possibly maximize the velocity of the thrown ball (Fortenbaugh & Fleisig, 2009). The upper and lower body influences pitching kinematics that ultimately affect ball velocity (Fortenbaugh, Fleisig, & Andrews, 2009).
Throwers that are able to efficiently use the kinetic chain are capable of maximizing the ball’s velocity (Fortenbaugh & Fleisig, 2009). When timing between the peak angular velocities of the pelvis and trunk increases, ball velocity was found to decrease (Urbin, Fleisig, Abebe, &
Andrews, 2013). It was found that balls thrown at a higher velocity have higher kinetic values about the elbow and shoulder (Fortenbaugh, Fleisig, & Andrews, 2009). Additionally, pitchers throwing at a higher ball velocity demonstrated greater maximum shoulder external rotation and forward trunk tilt angles at ball release (Fleisig, Bolt, Fortenbaugh, Wilk, & Andrews, 2011).
Hirashima et al. (2008) found that ball velocity dependent torques about the shoulder, elbow, and wrist were created by the angular velocity of the forearm that originated from trunk and shoulder joint torques in the earlier phases of the throwing motion. Catchers demonstrate throwing motions similar to pitchers, however with a shortened motion (Plummer & Oliver, 2013).
However, the ball velocity for pitchers is still greater than those of catchers (Plummer & Oliver, 2014). Ball velocity was not compromised due to pitchers changing delivery styles (Keeley, Oliver, & Dougherty, 2012). After comparison of two different age group of catchers, grouped
9-14 and 15-23, Plummer and Oliver (2013) discovered that ball velocity would be increased as the catcher matures and have further muscular gains in strength. It was found that utilizing different throwing distances to train for faster ball velocities was not necessarily effective (Fleisig, Bolt, Fortenbaugh, Wilk, & Andrews, 2011).
Injury
Due to the vast amount of research on pitcher’s and their mechanics and pathomechanics, a substantial amount of research is related potential injury risks and practices that could limit the chance of injury. Overhead throwing athletes, such as baseball players, have an increased risk for overuse injuries with the shoulder and elbow commonly sustaining injury (Han, Kim, Lim, Park,
& Oh, 2009). The high speeds of the throwing motion have extreme repercussions to the dynamic stabilizing structures in the upper body, raising the risk of injury (Meister, 2000). A catcher’s ability to optimally sequence the throwing motion could potentially decrease the forces on the elbow, shoulder, and trunk, thus lowering the risk for injury that could occur due to improper motions (Plummer & Oliver, 2013). In addition, to minimize the strain on the throwing arm and reduce risk of injury is through an efficient total body mechanical sequence (Fortenbaugh & Fleisig, 2009). In order to achieve this mechanical efficiency, Fortenbaugh and Fleisig (2009) suggested stronger legs and core muscles to sustain the larger loads rather than rely on the weaker and smaller arm muscles. By efficiently utilizing the kinetic chain during throwing, pitchers can minimize upper extremity kinetic values to reduce injury risk (Fortenbaugh & Fleisig, 2009). Kibler (1998) was able to conclude that when a 20% decrease in the transfer of energy from trunk, hip and proximal segments to the throwing arm would need an 80% increase in mass or at least a 34% more rotational velocity in the shoulder joint. Plummer and Oliver (2013) hypothesized that if wrong throwing mechanics are utilized then shoulder and
elbow moments will increase. Preventing pathomechanics and providing appropriate rehabilitation training programs could potentially be achieved with the knowledge of moments increasing about the shoulder and elbow during the throwing motion. (Plummer & Oliver, 2013).
Plummer and Oliver (2013) suggest those in immediate contact with catchers and their training should incorporate strength programs that target the rotator cuff in order to increase musculature and decrease any risk of epiphyseal injury.
Ulnar collateral ligament (UCL) injuries as well as superior labral tear from anterior to posterior (SLAP) in baseball players are becoming increasingly common, however exact reported findings could not be confirmed (Han, Kim, Lim, Park, & Oh, 2009). Consistent and repetitive high force throws correlates with high varus torque in the elbow, thus could result in gradual attenuation of the UCL (Fleisig, Bolt, Fortenbaugh, Wilk, & Andrews, 2011). Following recovery and rehabilitation from UCL and SLAP surgery, players should avoid maximum distance throws until the later stages of rehabilitation due to the increased varus torque and elbow extension velocity (Fleisig, Bolt, Fortenbaugh, Wilk, & Andrews, 2011). Additionally, rotator cuff injury was also fairly commonly seen in baseball players (Mazoué & Andrews, 2006). The overhead thrower usually would complain of discomfort in the neck or shoulder and observes a loss of throwing velocity after sustaining shoulder injury (Seroyer, Nho, Bach, Bush-Joseph, Nicholson, & Romeo, 2009). Comparing players of taller statures and heavier builds, Han et al. (2009) observed that these players were more prone to UCL injury and SLAP lesions.
Much like pitchers, catchers are commonly hampered by shoulder and elbow injuries, in addition to wrist injuries (Li, Zhou, Williams, Steele, Nguyen, Jäger, & Coleman, 2013). Efficient throwing mechanics resulted in lower shoulder torques and lower elbow valgus loads (Kibler &
Thomas, 2012). Pitchers who required operative treatment for rotator cuff tears did not return to
pre-injury performances levels (Namdari, Baldwin, Ahn, Huffman, & Sennett, 2011). Mazoué &
Andrews (2006) also found that professional pitchers who underwent operative treatment for rotator cuff tears had an extremely difficult chance to return to a competitive level of pitching.
Conclusion
Based on the aforementioned literature, past research focused predominantly on the pitcher’s throwing mechanics. The primary concern of many researchers studying baseball throwing motions focused on the sequencing of the body and kinetic chain, how throwing performance was affected by the sequencing of events, and if any injury implications exist.
Limited research pertains to the catcher, another imperative position in baseball that consistently throws more than any other player on the field. Therefore, by evaluating catcher throwing
motions, it would be possible to further assess the implications the catcher’s throwing mechanics has on performance, injury, and training.