Catchers play an integral role of defending against base runners. When the runner is attempting to steal second base, catchers first must receive the pitched ball in a deep crouched position. As the ball is caught, the catcher then simultaneously rises up from the squatted position and transfers the ball to the throwing hand. The catcher then externally rotates the shoulder to its maximum and proceeds to internally rotate the shoulder, extending the elbow at high velocities to throw the ball.
Having a quick pop time, defined as when the ball is caught to being released, and fast ball velocity increases the probabilities of catching base runners at second base. The caught stealing percentage, a performance statistic often highly coveted amongst baseball scouts, is calculated via: caught stealing / (stolen bases + caught stealing). Catchers endeavor to increase this percentage with the aid and training from their coaches. Thoroughly understanding the catcher’s throwing motion provides an additional asset to assist in the training and improvement of performance.
Three commonly seen techniques throwing to second base are: the traditional throw down, the pitch out, and throwing from the knees. The conventional method for throwing down to second base to catch base stealers is the traditional throw down. It is generally assumed amongst the baseball community is that on average, the pitch out would produce the fastest ball velocities, pop time, and total time to second base when utilized to throw down to second base. The pitch out, an unimpeded throw to second base, is frequently seen as the most quintessential strategy to throw out a runner stealing second (Fortenbaugh et al., 2010). Kneeling and throwing to second is assumed to have the quickest pop times.
This study investigated three throwing motions used by catchers throwing to second base, the potential differences in joint kinematics, and the effects on player performance. Professional catchers performed the required throwing tests in the research. Joint kinematics for the upper extremities as well as the pelvis for all test participants were scrutinized. Further analysis of the throws and its kinematic values drew plausible influences on player performance. Prospective training and intervention methods could be introduced to enhance performance values.
Joint Kinematics
The catcher’s ball speed and quickness is imperative to how successfully a runner is thrown out at second base, due to this, throwing mechanics could potentially be more concise (Fortenbaugh et al., 2010; Plummer & Oliver, 2013; Kibler, 1998). Upon analysis of the performance value of ball velocity, the pitch out registered the highest average ball velocities, recording velocities averaging 31.4 meters per second (113 km/h), when throwing down to second base.
Although this study was only capable of explaining roughly sixty to sixty-seven percent of possible joint kinematic factors influencing ball velocity, other previous studies have produced similar findings as well (Fortenbaugh & Fleisig, 2009; Matsuo et al., 2001;
Fortenbaugh & Fleisig, 2010; Fortenbaugh et al., 2010). Shoulder external rotation, trunk forward, and lateral tilt angles, as well as elbow extension, shoulder internal rotation, and trunk rotation velocities, plausible influencing kinematic factors for ball velocity, however, were significantly lower than traditional throw down measurements. The traditional throw down could possibly have exhibited higher shoulder external rotation angles to generate more ball velocity.
Previous research scrutinizing pitching mechanics and efficiency produced contradicting results.
Efficient pitchers were able to generate greater trunk and shoulder rotation velocities, thus throwing the ball faster, when compared to pitchers with inefficient mechanics (Fortenbaugh &
Fleisig, 2009). More pronounced trunk rotation could possible give pitchers and catchers a greater ability to maximally externally rotate the shoulder, which is often associated with increases in throwing velocity (Fortenbaugh & Fleisig, 2009; Matsuo et al., 2001; Oyama et al., 2014). It was proposed that the pitch out would require the least amount of trunk rotation velocity, followed by the traditional throw down requiring more, while throwing from a kneeling position would require the most amount of trunk rotation velocity. Significant differences can be seen in the trunk rotation velocity for all three throwing motions.
Due to the throwing motion characteristics of the traditional throw down, rising from a crouched position to the concise footwork to turn the body towards second base and then throwing the ball, an increased trunk rotation velocity is probably more prevalent than the pitch out (Fortenbaugh & Fleisig, 2009; Plummer & Oliver, 2013). As opposed to the traditional throw down, the pitch out begins the throwing motion already risen out of the squatted position, ready to catch the ball and then step and throw to second base; side-by-side comparisons can be seen in the two figures below (Fortenbaugh & Fleisig, 2010).
This forward movement motion occurring prior to the throw for the pitch out, versus the more stationary position of the traditional throw down, perchance relies less on trunk rotation while displaying a throwing motion utilizing more forward momentum, thus generating faster ball velocities. Resulting differences during the throw itself can arise due to the forward movement involving the entire body moving in a coordinated manner prior to throwing the ball (Hussain & Bari, 2011). Throwing from the knees impedes the catcher from utilizing the lower extremity to generate sufficient forces necessary to deliver the ball to second base effectively.
Consequently, it can be hypothesized that from this kneeling position, an increased trunk rotation velocity with additional forward lean of the trunk is imperative. Pitchers and position players strive for accurate and high velocity throws thus are often found to lean into their throws;
likewise, a catcher flexes the trunk forward and extending the elbow to amplify the energy to propel the ball towards second base with a whip like effect in the throwing arm (Escamilla et al., 2012; Fortenbaugh & Fleisig, 2009). Achieving this whip like effect would presumably have faster elbow extension velocities, while a motion that relies on pre-throw movements such as the pitch out would not necessitate as much. In spite of variations of the throwing motion, kneeling and throwing to second base would produce the slowest ball velocities, fundamentally compromising the total time to second base. Kinematic factors known to influence ball velocity were less pronounced from the pitch out. Nonetheless, upper extremity kinematics can only partially explain ball velocity influencing elements.
Analysis of pop time and the total measured time to second base revealed that the traditional throw down was slower than the pitch out. By professional baseball scouting standards, the desired total time, from catching the pitched ball to the ball being caught at second base after the catcher has thrown it, should be within 2.0 seconds (Sakurai et al., 1994). Striving to improve ball release times, catchers will often throw to second base from a kneeling position (Plummer & Oliver, 2011). Consistently between the three motions, shoulder external rotation degrees displayed positive relationships with pop time, while elbow extension velocity had negative correlations. Abducting the shoulder too much also had detrimental effects to the pop time. This could be due to the extra distance the arm needed to travel, thus increasing the time needed. Nevertheless, as a result of the concise motion, the kneeling position is able to clock in the fastest pop time when compared with the other two throwing motions.
The kinetic chain and stretch shortening cycle (SSC) and potential implications
The throwing motion acts in sequence to complete a chain of events from most proximal body segments to the most distal segments. This coordinated movement allows the body to generate and transfer the required energy to throw the baseball (Plummer & Oliver, 2013; Kibler, 1998). The transfer of energy in sequence from proximal to distal segments is often referred to as the kinetic chain (Zaremski & Krabak, 2012). Maximizing the ball velocity by virtue of this could pose as a beneficial tool to reduce strains on the throwing arm (Fortenbaugh & Fleisig, 2009; Fortenbaugh et al., 2009). It is conceivable that from the pitch out, the catcher is able to sequence the body segments from the lower to upper extremities prior to throwing while moving forward to generate forward momentum, together utilize the transfer of energy by means of the kinetic chain (Fortenbaugh & Fleisig, 2009; Matsuo et al., 2001). Increases in ball velocities could result if the kinetic chain is proficiently used during the throwing motion (Fortenbaugh &
Fleisig, 2009). It is believed that the safest and most methodical transfer of energy by effectively timing this chain which begins from the lower body, through the trunk, and finally into the upper limbs, and exiting into the ball (Davis et al., 2009; Urbin et al., 2013; Fortenbaugh, Fleisig, &
Andrews, 2009; Aguinaldo, Buttermore, & Chambers, 2007). The traditional throw down perhaps lacks the optimal transfer of energy from the lower body segments to the upper body, attributed to the rushed throwing motion requiring a quick hop to turn the body while compacting throwing movements when throwing the ball. The demand for the least amount of time required to throw to second base could undermine methodical throwing mechanics, thus could impart higher forces on the shoulder and elbow structures (Fortenbaugh & Fleisig, 2009;
Fortenbaugh & Fleisig, 2010; Plummer & Oliver, 2013; Kibler, 1998; Dun et al., 2008). Due to
time limitations to throw out a base runner, catchers could potentially trade off biomechanical efficiency and opt for quicker, shorter motions when under duress (Fortenbaugh et al., 2010).
The upper extremity transfer of kinetic energy occurs predominantly during the arm cock phase. Flexing the elbow during this phase allows passive inertial forces to assist in the external rotation of the shoulder. As the shoulder externally rotates further to its maximum, more time is allotted to produce and accumulate energy in the elastic soft tissues and muscle fibers that cross the shoulder complex. (Roach et al., 2013). Recoiling of the elastic elements will rapidly drive the shoulder to internally rotate and extend the elbow and create the high-powered movement necessary for overhead throwing (Roach et al., 2013). The elastic components in the body utilizes the stretch-shortening cycle, the coupling of muscle eccentric and concentric movements, which stimulates the body’s proprioceptors allowing the muscle to recruit more fibers to produce maximal force in the shortest given amount of time (Wilk et al., 1993; Carter et al., 2007).
Greater concentric forces can be produced when the muscle loads eccentrically faster because when the elastic elements are stressed more rebound forces are more readily available (Wilk et al., 1993). If an overhead athlete, such as a catcher, is able to abduct and rotate the shoulder externally further, faster ball velocities can be produced when the ball is released (Baker &
Ayers, 2014). Storing elastic energy in shoulder ligaments and tendons, however, has possible injury implications in both the shoulder structure as well as the elbow due repeated use and the high-energy transfer (Roach et al., 2013; Baker & Ayers, 2014; Byram et al., 2010). When the coordinated chain of events for throwing is established and sequenced efficiently, forces to the throwing arm can possibly be minimized and injury risks resulting from pathomechanics reduced (Plummer & Oliver, 2013). Microtraumas to shoulder components and soft tissues often surface due to continuous stressing of the shoulder structures, overuse injury and the thrower repeatedly
trying to gain extra power during the throwing motion (Park et al., 2002; Urbin et al., 2012; Chu et al., 2009; Oyama et al., 2014). Additionally, shoulder internal impingement symptoms could be credited to excessive external rotations when the shoulder is fully abducted during the throwing motion (Fleisig et al., 2011). If the catcher is unable to reach an ideal shoulder elevation during the throwing motion, added stresses could be placed on the shoulder and the elbow, ultimately leading to upper extremity injuries (Plummer & Oliver, 2011). If the overhead throwing athlete improperly sequences trunk rotation events, increases in shoulder external rotation angles could occur to compensate for a loss of additional muscular strength, which could predispose the thrower to shoulder injuries (Oyama et al., 2014). The ability to properly sequence the trunk could be instrumental in protecting the thrower’s shoulder (Oyama et al., 2014). Inefficient sequencing of body segments and mechanics during the throwing motion poses as inherent risks of injury for the overhead thrower (Plummer & Oliver, 2011; Oyama et al., 2014). Presuming that the timing of the coordinated events in the kinetic chain does not occur, higher joint kinematics and kinetics could be produced in order to compensate for momentum loss that is needed to sustain necessary ball velocities (Urbin et al., 2013).
Applications
Comprehending joint kinematics for catchers throwing to second base can provide training support to coaching staff and trainers. Based on the findings from this study, when throwing to second base, the pitch out was the fastest in relation to the total time to second base as well as ball velocities. The general assumption that the pitch out is the quickest method to impede attempted stolen bases at second was validated in this study. Nonetheless, steps can still be taken to improve performance. Since ball velocity highly influences the overall elapsed time to second base, slightly slower pop times will not hinder overall performance. From the results of
the study, although the pitch out produced a significantly slower pop time than throwing from a kneeling position, the pitch out was still able to produce the quickest overall time to second base.
It is with this notion that increasing ball velocity should be a priority for catchers.
Increases in certain joint kinematic parameters have shown positive relationships with increases in ball velocity for each of the three throwing motions. As the catcher prepares to throw, rotating the shoulder externally further will allow more energy to be stored in the elastic elements of the shoulder muscle complex (Baker & Ayers, 2014; Roach et al., 2013; Carter et al., 2007; Wilk et al., 1993). Consequently, with more shoulder external rotation and abduction, faster velocities will be produced when the ball is thrown by means of the pitch out, traditional throw down, and throwing from the knees (Baker & Ayers, 2014). If the catcher is additionally able to have increased rotation velocities and flexion angles of the trunk, while explosively extending the elbow during the arm acceleration phase of the throwing motion, ball velocities can also potentially increase (Escamilla et al., 2012; Fortenbaugh & Fleisig, 2009). Throwing from a kneeling position’s ball velocity significantly benefits from an increase in trunk rotation velocity. However, trunk tilting the trunk too far to the left will impede the catcher from generating faster ball velocities. It can be recommended that catchers lacking shoulder and trunk flexibility collaborate with their respective training staff to safely improve the range of motion for shoulder external rotation as well as overall trunk rotation. Additionally, with the training staff, it is advisable that trunk rotation exercises also be performed to safely improve rotation velocities.
During the course of a baseball game, if a base runner is attempting to steal second base, it is recommended that the pitch out be implemented if it will not result in a base on balls. When compared to the other two throwing motions, throwing from the knees and traditional throw
down, the pitch out produces the fastest times to second base. Thus, faster times to second base will result in higher possibilities of unsuccessful base steal attempts. Ideally, the total time to second base should be within 2.0 seconds (Sakurai et al., 1994). However, in unfavorable counts with three balls, it is always recommended that the traditional throw down be the throwing motion employed. Although the traditional throw down requires more time to second base than the pitch out, the traditional throw down produces similar pop times. By increasing the ball velocities when throwing by virtue of the traditional throw down, similar if not quicker overall time to second base can be recorded when compared to the pitch out.
Throwing from the knees is generally assumed to be a very quick motion and technique to throw to second base when a runner is attempting to steal. Contrary to this belief, throwing from a kneeling position is not the fastest method. Although throwing from the knees produces the quickest pop times when compared with the traditional throw down and pitch out, kneeling to throw lacks sufficient ball velocity. If ball velocities can increase by ten-percent when throwing from a kneeling position, performance results similar to the traditional throw and pitch out can be achieved. Consequently, increase in ball velocity is instrumental to the success of catchers inhibiting stolen bases. Additionally, because trunk extension negatively impacts the ball velocity when throwing from a kneeling position, it is preferable for coaches and training staff to also observe the catcher’s trunk and correct for excessive angles.
It has been well documented by previous studies that maximizing ball velocity performance and decreasing the risk of injury is feasible with the incorporation of resistance and plyometric training during the off-season, preseason, as well as in-season (Escamilla et al., 2010;
Zaremski & Krabak, 2012). Increasing neuromuscular stabilization and musculature of the shoulder complex is essential for curbing shoulder injuries in baseball players (Carter et al.,
2007). The stretch-shortening cycle, which is the fundamental concept of plyometric training exercises, is principally the type of muscle contraction that is observed in overhead throwing (Grezios et al., 2006; Escamilla et al., 2010; Escamilla et al., 2012). It can be surmised from both Escamilla et al. (2010, 2012) and Carter et al. (2007) investigations that resistance training and plyometric training increases muscular strength, moreover, plyometric training is highly influential on ball velocity. After 6-weeks of resistance training consisting of plyometric, Throwers Ten program, and Keiser Pneumatic programs, Escamilla et al. (2012) found increases
in muscular strength for high school baseball players, however only the group performing plyometric exercises exhibited significantly greater throwing velocities. Following an 8-week plyometric protocol following the Ballistics Six program, significant enhancements in ball velocity were seen in the tested baseball players (Carter et al., 2007). This plyometric program was designed to imitate the overhead throwing motion and can be categorized as a sport-specific strength and conditioning exercise program (Carter et al., 2007). It was recommended that implementing high volume upper-extremity plyometric program such as the Ballistics Six could result in improvements in ball velocity and muscular strength in the upper extremities (Carter et al., 2007). Rhea et al. (2008) suggested instead of prolonged aerobic training for cardiovascular endurance, training should be substituted with higher intensity, interval training type exercises or numerous sprinting training exercises. Continuous aerobic training was found to be detrimental to power performance results, alternatively, training and conditioning should be focused towards maintaining or increasing muscle power (Rhea et al., 2008). Strengthening programs should be implemented during the course of rehabilitation, with additional emphasis on post-workout stretching and therapy (Park et al., 2002; Zaremski & Krabak, 2012). Explosive, plyometric exercises and throwing programs should be initiated during the latter stages of rehabilitation
(Zaremski & Krabak, 2012). Advancing to each stage of rehabilitation and finally returning to play would be at the discretion of the attending physician and athletic trainers deeming the player’s injuries fully healed and fit to perform throws to second base (Fleisig et al., 2011). It is thus advisable for baseball teams to have and/or continue training programs that encompass both resistance and plyometric training.