What do batters use to coordinate and control their movements?
What do expert batters use to coordinate and control their movements?
Garrett Boyum
Missouri State University
April 6, 2020
I. Introduction
One of the main propositions of ecological psychology put forth by JJ Gibson (1979) on motor control is that the environment supplies specifying information for the performer to directly interact with to successfully perform the task. This is particularly useful in the examination and understanding of expert performance in sport where athletes have to face the complex and dynamic challenges that encapsulate everything from the complexity and dynamic nature of their human movement system to the complex and dynamic nature of the environment that they are having to coordinate their movements to. This is no more true than in baseball batting. The difficulty of trying to hit a round ball with a round bat is hard enough but coupled with the ball traveling up to speeds of 105 mph with various amounts of horizontal and vertical movement makes hitting a baseball one of the hardest skills in all of sports. Yet it’s not good enough just to be able to hit the ball, the ball must be hit in such a way as to not create an out by the defense. How is it that elite baseball batters are able to achieve the success that they do? What information are they connecting to in the environment that is enabling them to barrel balls thrown by pitchers who often throw multiple pitches? This study seeks to understand to what extent the pitcher’s kinematics and ball flight information provide specifying information for the control of action for baseball batters.
II. Literature Review[1]
Around the turn of the decade of 1980 several foundational publications marked the emergence of ecological psychology (Gibson, 1979; Turvey, 1977; Michaels & Carello, 1981; and Turvey, Shaw, Reed, & Mace, 1981) and dynamical systems theory (Kugler, Kelso, and Turvey, 1980, 1982) into the field of motor behavior which has had a profound impact on the study of expert sport performance (Beek et al., 2003). A second major idea posited by an ecological approach is that there is an information-environment relationship that exists to specify invariant variables emerging from constraints (Beek et al., 2003) which creates a vital reciprocal performer-environment relationship. These constraints consisted not only of universal constraints, such as natural laws like gravity, but also ecological constraints that are unique to the eco-niches of certain organisms (Beek et al., 2003; J. J. Gibson, 1979). These ideas were expanded upon by Newell (1986) Constraints Model which organized constraints into three general categories; the organism, the task, and the environment. The general assumption from an ecological approach is that expert performance results from the attunement, becoming highly sensitive to and the exploitation of higher order, specifying informational variables (Beek et al., 2003; Pinder et al., 2009). Yet due to the abstract and dynamic nature of specifying information can make it difficult to pinpoint and highlight these variables (Beek et al., 2003). There is a need for research that examines the effects of practice design on an athlete’s perception-action couplings to aid in their ability to attune to invariant, consistent across variations, information (Williams et al., 1999).
There have been few baseball batting studies examining the effects of batting off a pitching machine as compared to facing a real pitcher. However, this question has been examined with cricket batsmen which found that batting off a pitching machine produced significantly different swing kinematics as compared to when facing a live bowler (Pinder et al., 2009). From this they concluded that pre-pitch kinematics of the bowler provides specifying information necessary for a batter to guide their actions. One limitation of their study was it did not examine what specific invariant variables, or specifying information batters were connecting to with regards to the bowler’s kinematics to regulate and control their action. While there have been baseball studies that have sought to study the visual information baseball batters may use to coordinate their movement many have studied biomechanics and information picked up to regulate action separate from one another (Müller et al., 2014). This is largely based around the question of representative design first proposed by Brunswik (1956). Representativeness should have both functionality; the extent to which the same information sources are available as in the original environment, and action fidelity; the similarity of the emergence of movement behaviors to their original context (Krause et al., 2019). Essential information sources that a baseball batter utilizes to couple his movements to successfully hit a pitch emerge from the visual information produced by the pitcher’s kinematics and the subsequent ball flight (Müller et al., 2014; Van Der Kamp et al., 2008). In this regard, studies should aim to preserve key fundamental information sources that afford subjects the opportunity for similar movement behavior to emerge through the perception action coupling to these sources of information (Araújo et al., 2007; Müller et al., 2014). Yet it is common for baseball studies to omit any one of these key source of information through the use of pitching machines (Cassidy, 2000; Higuchi et al., 2016; Katsumata, 2007; Kidokoro et al., 2020) or omitting major specifying information sources all together by using a batting tee (Dowling & Fleisig, 2016; Tago et al., 2018). Which is problematic as this may obscure or confound the phenomenon of interest they meant to investigate (Araújo et al., 2007).
An investigation into what informational sources baseball batters utilize to regulate their actions has predominantly been examined through gaze tracking and occlusion studies (Gray & Cañal-Bruland, 2018; Higuchi et al., 2016; Kato & Fukuda, 2002; Müller et al., 2014, 2017; Paull & Glencross, 1997; Ranganathan & Carlton, 2007; Shank & Haywood, 1987; Takeuchi & Inomata, 2009). These various studies have demonstrated that batters utilize pre-pitch information to anticipate future ball flight and location to initiate their action by guiding their gross body movements to put them in a better position to be able to capitalize on later ball flight information for the online control of the swing under extreme temporospatial constraints (Müller et al., 2017; Müller & Abernethy, 2012). It has been found that batters utilize early ball flight information to guide their actions (Higuchi et al., 2016) and late ball flight information to make minor error corrections for bat-ball interception (Müller & Abernethy, 2012).
Studies into the gaze behavior of batters have found that expert batters tend to have more fixation points on pitcher’s pre-pitch movements as well as longer gaze fixations than novices (Gray, 2017a; Kato & Fukuda, 2002). While gaze behavior research on ball flight has shown that batters struggle to keep their eyes on the ball all the way to bat ball collision likely due to the eye not being able to rotate fast enough to continue to track the ball as it gets closer to home plate (Bahill & LaRitz, 1984). This may be why elite batters may combine both head and eye movements to track ball flight as opposed to novices who gravated to move one or the other (Fogt & Zimmerman, 2014; Gray, 2017b; Kishita et al., 2020). Batters tended to initially track the ball using head movement before engaging eye movement to track the pitch (Kishita et al., 2020). During ball flight batters will also employ saccades, where the eyes jump rapidly from one spot to another, to be able to track the ball to contact (Bahill & LaRitz, 1984; Fogt & Zimmerman, 2014; Kishita et al., 2020; Mann et al., 2013). Elite batters were found to initiate their saccades later enabling them more time to pick up ball flight information (Kishita et al., 2020) as the performer is effectively blind during a saccade as minimal information is able to be gathered (Gray, 2017b).
A limitation within much of this research investigating the visual information utilized by hitters have decoupled perception from action (Cassidy, 2000; Kato & Fukuda, 2002; Müller et al., 2017; Paull & Glencross, 1997; Takeuchi & Inomata, 2009). Many of these studies instead use declarative knowledge or button pressing to infer what the performer would have done. This is problematic for several reasons. A performer may be able to quickly and accurately describe or react to visual information but that does not necessarily mean a proportionally accurate coordinated movement solution. There is also a distinct difference between how the visual system is engaged in declarative tasks compared to strictly motor tasks. There are two visual sub-subsystems used for visual perception for the guidance and control of action: the ventral and dorsal systems. The ventral system main role is in the identification of objects, events, and places which can contribute to guidance and regulation of action through knowledge about what the environment affords for action (Van Der Kamp et al., 2008). Whereas the dorsal system utilizes online visual information directly to coordinate and control movement (Van Der Kamp et al., 2008). During action a reciprocal relationship between these two systems is utilized to guide and regulate action (Van Der Kamp et al., 2008). In declarative or verbalisation tasks that include movement execution cause the ventral system to become primarily pathway to be activated (Van Der Kamp et al., 2008). By doing so the performer may analyze their behavior more consciously than under normal conditions, not engaging the dorsal stream. To engage the dorsal system the performer requires online visual information to exploit (Van Der Kamp et al., 2008). When the dorsal stream is primarily engaged the performer may not be consciously aware of how they are moving or what information they are utilizing as the regulation of action is implicit (Van Der Kamp et al., 2008). As a result, studies that decouple perception from action may not be investigating the behavior of interest as the desired behavior isn’t allowed to emerge (Araújo et al., 2007; Van Der Kamp et al., 2008). Allowing individuals to couple their actions to their perceptions has been shown to improve perceptual accuracy (Oudejans et al., 1996). This raises questions about the ability of studies that have decoupled perception and action to generalize their results back to the performance context (Araújo et al., 2007; Van Der Kamp et al., 2008). This has led to a gap in our understanding of how baseball batter’s movement emerges to quickly, effectively, and resourcefully intercept a pitched ball leading to an over or underestimation or misguided understanding of experts abilities. While these studies may tell us what information they are attending to, the ability to explain how batters use that information to coordinate their actions needs to be investigated further.
The question of what specifying information do batters use to successfully coordinate their swing is pertinent to baseball coaches practice design for the development of their hitters. If the attunement to invariant variables allows athletes to exploit that specifying information to coordinate an effective motor solution it becomes imperative to understand how we can enhance an athlete’s ability to become more highly attuned to that specifying information. The primary purpose of this study is to investigate how hitters can become more attuned to the specifying variables that lead to improved batting performance. This study also seeks to examine to what extent pitcher’s provide specifying information for hitters or whether ball flight information is more specifying for the control of action for baseball hitters.
One possible way that has been proposed for practitioners to help guide their athletes search for specifying information in the task environment is to highlight key information sources (Renshaw et al., 2019). In their book they describe how cricketers could improve their batting by highlighting portions of a blower’s body or ball. For example the bowler’s throwing hand or wrist could be painted a distinguishable color for the batter to be more easily able to distinguish pre-pitch kinematics. Or the ball could be modified to have a thick line around it or one half colored so the spin of the ball and its subsequent trajectory become more evident. This could be similarly done to train baseball batters. Although this suggested practice is founded on sound reason and theory there is no evidence to show whether or not it would be effective at improving batting performance. There is no clear definitive evidence on what specifying variables hitters attune to given the limitations of declarative knowledge and the fact that performers may not even be aware of what specific information they are using to control actions (Van Der Kamp et al., 2008). Therefore, further investigation is warranted into what variables batters may be using to successfully coordinate their movements.
Pitching machines are not only ubiquitous in baseball batting research but also training. This is because they can provide batters with more consistent and accurate pitches with game-like velocity and or pitch movement while also reducing the injury risk and logistical difficulties that come with overuse injuries and an adequate amount of skilled batting practice throwers (Dennis et al., 2005; Pinder et al., 2009, 2011). Despite the benefits pitching machines provide, research has demonstrated that batter’s kinematics and timing are significantly different than when they face a real opponent (Carboch et al., 2014; A. P. Gibson & Adams, 1989; Krause et al., 2019; Pinder et al., 2009; Renshaw et al., 2007). Additionally, batters will often “park” their eyes on the location where the ball comes out of the machine (Croft et al., 2010) suggesting a major difference in the gaze behavior exhibited when facing a live opponent. Yet it is not known to what extent this affects skill acquisition of baseball batters, if at all. Does the loss of pre-pitch information significantly inhibit a batter’s ability to detect invariant information for batting when they go back to facing an actual pitcher? Could this lead to batters becoming attuned to non-specifying information such as an over reliance on ball flight information?
III. Hypothesis
We hypothesize that batters that train off of a pitching motion will perform better than those that practice on pitching machines only. Additionally, we believe that if you highlight pre-pitch and or ball flight information it will aid in facilitating a batter’s search for specifying information leading to better performance.
IV. Methods
Participants
Sixty participants were selected from several baseball training facilities, thirty six batters, and twenty four over arm pitchers were recruited to throw to the batters in the pre, post, and transfer test. Pitchers needed to be able to have an average throwing velocity of 75 mph to be included in the study. Participants to be included in this study are to be between the ages of 16-19 years old. All participants must be physically healthy, with no current injuries and medically cleared to participate in athletics. Ethical clearance was approved by Missouri State University’s ethics committee.
Procedure and task conditions
Participants were divided into six groups and randomly assigned one of six experimental conditions: 1) pitching machine only, 2) pitching motion only, 3) pitching machine only with highlighted ball flight information, 4) pitching motion only with highlighted ball flight information, 5) pitching machine only with pitching motion feed, 6) pitching motion only with highlighted release point information. Each group performed 12 sessions of their given task over a 4 week period. Coaches were allowed to design their training session how they saw fit as long as they stayed within the group parameters. Coaches were allowed to alter task constraints such as number of pitches, ball pitched distance, pitch type, etc. All practices were required to be written as practice plans to be submitted beforehand for approval to make sure it followed the studies guidelines. A pre-test, post-test, and transfer test were used to determine what effect the training conditions had on batting performance. For the pre and post test batters would get 24 pitches total broken up into three rounds of eight thrown by a pitcher. The pitcher was instructed to throw his full arsenal of pitches. Batters were evaluated on their batted ball contact, swing and miss rate, and hit probability determined by measuring their exit velocity and launch angle. These three measurements were the independent variables used in this study. Due to ethical responsibility of the researchers to minimize harm and protect pitchers from overuse injuries they were limited to 45 pitches in each of the testing phases.
Apparatus and testing setup
Batters were to hit against a pitcher pitching from a mound 60 ft 6 inch away from home plate pitching to a catcher. A Stalker Pro IIs was used to record and measure the pitcher’s pitch speed and spin rate. A Rapsodo 2.0 Hitting unit was used to record exit velocity and launch angle batted ball data.
Data Analysis
The results were analyzed using a three-way ANOVA followed by a Post Hoc analysis were used to determine if any group saw statistically significant improvements. It is expected that the groups that received the pitching motion training saw the greatest improvements. While the pitching machine only group performed worse. It could be the case that the anecdotal stories of coaches of having success using pitching machines is supported by the data. This could be especially true of the groups that had additional information highlighted especially with the ball flight information being highlighted.
Discussion
The results of this study would add to the existing literature by building upon past studies on baseball batting that have incorporated both the use of pitching machines and live pithers. In addition to other fast ball intercept sports, such as cricket and tennis. This study would also contribute to the theoretical framework of ecological psychology. The results of this study would provide greater insight into how motor behavior emerges through the perception-action coupling. Through this experimental design we could gain a better understanding of how to utilize the principles of Newell’s (1986) Constraint Led approach for skill acquisition. This not only has implications for the field of psychological perception and motor control but also practical significance for sport coaches.
References
Gibson, J. J. (1979). The Ecological Approach to Visual Perception. Boston: Houghton Mifflin.
