Baseball Batting Research Articles

A Pilot Study of Horizontal Head and Eye Rotations in Baseball Batting.

The purpose of the study was to measure and compare horizontal head and eye tracking movements as baseball batters "took" pitches and swung at baseball pitches. Two former college baseball players were tested in two conditions. A pitching machine was used to project tennis balls toward the subjects. In the first condition, subjects acted as if they were taking (i.e., not swinging) the pitches. In the second condition, subjects attempted to bat the pitched balls. Head movements were measured with an inertial sensor; eye movements were measured with a video eye tracker. For each condition, the relationship between the horizontal head and eye rotations was similar for the two subjects, as were the overall head-, eye-, and gaze-tracking strategies. In the "take" condition, head movements in the direction of the ball were larger than eye movements for much of the pitch trajectory. Large eye movements occurred only late in the pitch trajectory. Gaze was directed near the ball until approximately 150 milliseconds before the ball arrived at the batter, at which time gaze was directed ahead of the ball to a location near that occupied when the ball crosses the plate. In the "swing" condition, head movements in the direction of the ball were larger than eye movements throughout the pitch trajectory. Gaze was directed near the ball until approximately 50 to 60 milliseconds prior to pitch arrival at the batter. Horizontal head rotations were larger than horizontal eye rotations in both the "take" and "swing" conditions. Gaze was directed ahead of the ball late in the pitch trajectory in the "take" condition, whereas gaze was directed near the ball throughout much of the pitch trajectory in the "swing" condition.

Coordination of hitting movement revealed in baseball tee-batting

ABSTRACTBaseball batters must react to pitches delivered to different locations within the strike zone by modulating their movements. In tee-batting practice, such batters place a ball on a tee stand at a location, where they intend to hit the ball, assuming a particular pitch’s trajectory. In the present study, we analysed three-dimensional movements in tee-batting to identify characteristics of the batters’ intended impact locations across the strike zone, thereby investigating spatiotemporal features of movement modulation. More specifically, 10 experienced baseball batters performed tee-batting at their preferred impact locations at nine different heights and courses within the strike zone. The distribution of impact locations showed regularity, i.e., the location shifted forward for balls placed high and inside, while it shifted backward for balls placed low and outside. Furthermore, trunk and arm movements showed systematic modulation as the impact locations changed. The duration of bat movement was also location dependent, i.e., hitting the inside ball took more time than hitting the outside ball. Our results indicate that even though movements among body segments were properly coordinated to adjust the bat swing for different impact locations, fine timing adjustments were also required to hit the ball at those preferred impact locations and therefore properly react to differences in flight paths.

Applicability of ultrasonography for evaluating trunk muscles size in athletes: a study focused on baseball batters.

[Purpose] Recently, we demonstrated that the thicknesses of trunk muscles measured using ultrasonography were correlated strongly with the cross-sectional areas measured using magnetic resonance imaging in untrained subjects. To further explore the applicability of ultrasonography in the clinical setting, the present study examined the correlation between ultrasonography-measured thicknesses and magnetic resonance imaging-measured cross-sectional areas of trunk muscles in athletes with trained trunk muscles. [Subjects and Methods] The thicknesses and cross-sectional areas at total 10 sites of the bilateral sides of the upper, central, and lower parts of the rectus abdominis, abdominal wall, and multifidus lumborum in 30 male baseball batters were measured. [Results] Overall thicknesses and cross-sectional areas of the trunk muscles in baseball batters were higher than those in untrained subjects who participated in our previous study. The ultrasonography-measured thicknesses at all 10 sites of the trunk muscles correlated highly with the magnetic resonance imaging-measured cross-sectional areas in baseball batters. [Conclusion] These results suggest that the thicknesses of the trunk muscles measured using ultrasonography can be used as a surrogate marker for the cross-sectional area measured using magnetic resonance imaging, in athletes who have larger trunk muscles than that of untrained subjects.

Movement of bat during swing according to course in baseball batting

Movement of bat during swing according to course in baseball batting

野球のバッティングにおけるタイミング制御

野球のバッティングにおけるタイミング制御

PVDFフィルムを用いた野球のバッティングにおける衝突位置検出に関する検討

PVDFフィルムを用いた野球のバッティングにおける衝突位置検出に関する検討

野球のバッティングにおける下肢および体幹の力学的エネルギーの流れ

野球のバッティングにおける下肢および体幹の力学的エネルギーの流れ

野球の打撃におけるローリングの速さを決定する力学的要因

野球の打撃におけるローリングの速さを決定する力学的要因

野球の投手-打者対戦からみたバッティングの時間構造

野球では，投手がボールをリリースしてからわずか400ms程度で打者の手元に到達する．打者は，この極めて短い時間内にボールの球種やコースを判断し，その軌道に応じて時空間的に高い精度で打撃しなければならない．本稿では，実戦形式の投手-打者対戦における打者の運動を計測した結果を例に，バッティングの時間構造について解説する．打者は，ストレートとチェンジアップという球速の異なる球種がランダムに投じられた時，ボールリリース後約300msまではほぼ同じ挙動を示すが，その後の身体重心（腰部）の沈み込みの長さを調整することで遅い球に対応していた．

下半身の筋パワー変化に着目したバットスイングの巧拙の比較

下半身の筋パワー変化に着目したバットスイングの巧拙の比較

打者は打席で何をしているのか？打撃パフォーマンス分析にむけたバーチャルリアリティの活用

一流の打者がどのように打撃を制御しているのかについてはよく分かっていない．そこには二つの課題があると思われる．行動計測と条件統制の難しさである．筆者らはこれらの問題を解決する方法としてバーチャルリアリティ（VR）技術に注目している．VR技術を導入することにより，高い臨場感がありながら統制された条件下で打者の行動を計測でき，打撃パフォーマンスの理解につながると期待される．本稿では，リアリティのある打者体験を実現するためのVR技術とその指針について概観するとともに，筆者らが開発している打者用VRシステム，およびそれを用いた計測事例について紹介する．

Adaptability of expert visual anticipation in baseball batting

ABSTRACTBy manipulating stimulus variation in terms of opponent pitcher actions, this study investigated the capability of expert (n = 30) and near-expert (n = 95) professional baseball batters to adapt anticipation skill when using the video simulation temporal occlusion paradigm. Participants watched in-game footage of two pitchers, one after the other, that was temporally occluded at ball release and various points during ball flight. They were required to make a written prediction of pitch types and locations. Per cent accuracy was calculated for pitch type, for pitch location, and for type and location combined. Results indicated that experts and near-experts could adapt their anticipation to predict above guessing level across both pitchers, but adaptation to the left-handed pitcher was poorer than the right-handed pitcher. Small-to-moderate effect sizes were found in terms of superior adaptation by experts over near-experts at the ball release and early ball flight occlusion conditions. The findings of this study extend theoretical and applied knowledge of expertise in striking sports. Practical application of the instruments and findings are discussed in terms of applied researchers, practitioners and high-performance staff in professional sporting organisations.

A Comparative Analysis of Biomechanical Factors and Premotor Time of Body Muscles between Elite College and Amateur Baseball Players during the Baseball Batting Motion

Purpose: The aim of this study was to analyze biomechanical factors and PMT (premotor time) of bodymuscles between elite college and amateur baseball players during the baseball batting motion.Method: Kinematic and electromyographic data were obtained for 10 elite college baseball players and 10amateur baseball players who participated in this study. All motion capture data were collected at 200 Hzusing 8 VICON cameras and the PMT of muscles was recorded using a Delsys Trigno wireless system. Thepeak mean bat speed and the peak mean angular velocities of trunk, pelvis, and bat with PMT of 16 bodymuscles were computed. These kinematic and PMT data of both groups were compared by independentt-tests (p < .05).Results: The pelvis, trunk, and bat showed a sequence of angular velocity value during baseball batting.The PMTs of right tibialis anterior, left gastrocnemius, external oblique, and erector spinae were significantlydifferent between the two groups.Conclusion: The PMT of body muscles was related to the shifting of body and rotation of the pelvis andthe trunk segment, and this action can be considered the coordinated muscle activity of the lower andupper body.

Empirical Bayesball Remixed: Empirical Bayes Methods for Longitudinal Data

SummaryEmpirical Bayes methods for Gaussian and binomial compound decision problems involving longitudinal data are considered. A recent convex optimization reformulation of the nonparametric maximum likelihood estimator of Kiefer and Wolfowitz (Annals of Mathematical Statistics 1956; 27: 887–906) is employed to construct nonparametric Bayes rules for compound decisions. The methods are illustrated with an application to predict baseball batting averages, and the age profile of batting performance. An important aspect of the empirical application is the general bivariate specification of the distribution of heterogeneous location and scale effects for players that exhibits a weak positive association between location and scale attributes. Prediction of players' batting averages for 2012 based on performance in the prior decade using the proposed methods shows substantially improved performance over more naive methods with more restrictive treatment of unobserved heterogeneity. Comparisons are also made with nonparametric Bayesian methods based on Dirichlet process priors, which can be viewed as a regularized, or smoothed, version of the Kiefer–Wolfowitz method. Copyright © 2016 John Wiley &amp; Sons, Ltd.

한국프로야구에서 타자력 지수 제안

야구 타자의 능력을 측정하는 많은 세이버메트릭스 통계량들 중에서 WAR은 미국프로야구에서 가장 많이 사용하는 통계량이다. 그러나 한국프로야구 자료에는 수비에 관련된 변수에 포함된 야구장 요인, 포지션조정 그리고 리그 조정 통계량들이 존재하지 않으므로 WAR을 한국프로야구에 적용하는 데에는 문제가 있다. 본 연구에서는 타자의 능력을 측정하는 대안적인 세이버메트릭스 통계량을 제안하여 미국프로야구 뿐만 아니라 한국프로야구에서도 동시에 사용할 수 있도록 한다. 본 연구에서 제안한 타자력 지수 모형은 한국프로야구와 미국프로야구 타자들에 대한 다섯 종류의 통계량을 사용하여 개발한다. 우선 2015년도 최소 규정 타석을 만족한 미국프로야구 타자들의 자료를 바탕으로 타자력 지수 모형을 개발한다. 미국프로야구 타자들의 WAR과 비교하면서 본 연구에서 제안한 타자력 지수의 능력의 타당성을 검토한다. 다음으로 이 모형을 2015년도 한국프로야구 자료에 적용하여 한국형 타자력 지수를 제안한다. 한국프로야구 타자력 지수를 서로 다른 팀별, 나이별, 포지션별로 통계적으로 분석하고, 타자력 지수와 그들의 연봉과의 선형관계성을 토론한다. 연봉에 관한 회귀모형의 신뢰영역을 바탕으로 연봉책정의 적절함에 따라 46명의 타자를 세 그룹으로 할당하고, 세 그룹에 속한 연봉을 다양한 인자에 대하여 통계적으로 탐색한다. Among lots of sabermetric statistics for baseball batters' ability, the wins above replacement (WAR) is the most popular statistic in MLB. However, there exists a difficulty applying WAR to KBO, since KBO data do not have position adjustment, league adjustment and park factor which are essential in calculating WAR. In this paper, using five statistics for both KBO and MLB qualified batters, we propose hitting ability index (HAI), an alternative sabermetric indices to represent batters' ability. Comparing HAI with WAR of MLB batters, we evaluate the validity of HAI and then applied HAI to 2015 KBO data in which HAI is analyzed statistically with respect to different teams, ages, and positions. Moreover, the linear relationship between KBO batter's HAI and their annual salary is discussed. Grouping 46 KBO batters based on confidence region of the regression model for annual salary, we also statistically investigate batter's annual salary in these groups with respect to several factors.

Instructional Design for Accelerated Macrocognitive Expertise in the Baseball Workplace.

The goal of accelerating expertise can leave researchers and trainers in human factors, naturalistic decision making, sport science, and expertise studies concerned about seemingly insufficient application of expert performance theories, findings and methods for training macrocognitive aspects of human performance. Video-occlusion methods perfected by sports expertise researchers have great instructional utility, in some cases offering an effective and inexpensive alternative to high-fidelity simulation. A key problem for instructional designers seems to be that expertise research done in laboratory and field settings doesn't get adequately translated into workplace training. Therefore, this article presents a framework for better linkage of expertise research/training across laboratory, field, and workplace settings. It also uses a case study to trace the development and implementation of a macrocognitive training program in the very challenging workplace of the baseball batters' box. This training, which was embedded for a full season in a college baseball team, targeted the perceptual-cognitive skill of pitch recognition that allows expert batters to circumvent limitations of human reaction time in order to hit a 90 mile-per-hour slider. While baseball batting has few analogous skills outside of sports, the instructional design principles of the training program developed to improve batting have wider applicability and implications. Its core operational principle, supported by information processing models but challenged by ecological models, decouples the perception-action link for targeted part-task training of the perception component, in much the same way that motor components routinely are isolated to leverage instructional efficiencies. After targeted perceptual training, perception and action were recoupled via transfer-appropriate tasks inspired by in situ research tasks. Using NCAA published statistics as performance measures, the cooperating team improved from middling performance to first in their conference in Runs Scored and team Batting Average. This case suggests that, beyond the usual considerations of effectiveness and efficiency, there are four challenges to embedded training in the workplace setting —namely: duration, curriculum, limited resources, and buy in. In the case reported here, and potentially in many domains beyond sports, part-task perceptual-cognitive training can improve targeted macrocognitive skills and thereby improve full-skill performance.

The effects of baseball bat mass properties on swing mechanics, ground reaction forces, and swing timing

Swing trajectory and ground reaction forces (GRF) of 30 collegiate baseball batters hitting a pitched ball were compared between a standard bat, a bat with extra weight about its barrel, and a bat with extra weight in its handle. It was hypothesised that when compared to a standard bat, only a handle-weighted bat would produce equivalent bat kinematics. It was also hypothesised that hitters would not produce equivalent GRFs for each weighted bat, but would maintain equivalent timing when compared to a standard bat. Data were collected utilising a 500 Hz motion capture system and 1,000 Hz force plate system. Data between bats were considered equivalent when the 95% confidence interval of the difference was contained entirely within ±5% of the standard bat mean value. The handle-weighted bat had equivalent kinematics, whereas the barrel-weighted bat did not. Both weighted bats had equivalent peak GRF variables. Neither weighted bat maintained equivalence in the timing of bat kinematics and some peak GRFs. The ability to maintain swing kinematics with a handle-weighted bat may have implications for swing training and warm-up. However, altered timings of kinematics and kinetics require further research to understand the implications on returning to a conventionally weighted bat.

Contributions of Joint Torques, Motion-dependent Term and Gravity to the Generation of Baseball Bat Head Speed

This study quantifies the dynamic contributions of joint torques, motion-dependent term, and gravity to the generation of baseball bat head speed. Baseball batting is considered one of the most difficult tasks in sports motions. The batter is required to increase the bat head speed within a short time and move the bat into the hitting point with proper timing. Based on multi-body dynamics, a high speed swing motion is caused by not only joint torques and gravity but also motion-dependent term (MDT). The MDT consisting of centrifugal force, Coriolis force and gyro moment shows the dynamic characteristics of multi-segment motion. Five collegiate baseball players participated in this experiment. They performed hitting a teed ball as strong as possible. The whole-body segments with bat were modelled as a system of sixteen-rigid linked segments, and anatomical constraint axes of the elbow, wrist, knee and ankle joints were modelled with geometrical constraint equations in order to consider the degree of freedom (DOF) of the joint. The equation of motion for the whole-body and bat was obtained by considering modelling errors, such as residual joint force and moment, and fluctuations in segment’ lengths and joint constraint axes. Kinetic data of each hand and each foot were obtained by using an instrumented bat equipped with 28 strain gauges and 3 force platforms, respectively. The dynamic contributions of the joint moments, the motion-dependent term and the gravity term to the bat head speed were derived from the time integration of the equation of motion for the system. The results show that motion-dependent term is the largest contributor to the bat head speed in the last quarter of the forward swing phase. The contributions of the gravity and modelling error terms show small values. Motion dependent term is main generating factor to the head speed at the ball impact in baseball batting motion.

Kinetic Analyses on Increase of Bat Head Speed in Baseball Batting

Kinetic Analyses on Increase of Bat Head Speed in Baseball Batting

野球打撃動作における身体関節トルクの累積的効果

Motion-dependent term (MDT), which consists of centrifugal force, Coriolis force and gyroscopic effect moment expressed in the equation of motion for a multi-link system, plays significant roles in the generation of bat head speed through not instantaneous effect but cumulative effect of the exerting joint torques in baseball batting. According to our previous studies that calculate dynamics contributions of the whole-body joint torques considering generating factor of the MDT, the forward/backward rotational torque (FBR torque) at torso joint plays a significant role in the generation of bat head speed. These studies, however, show that the lower limb joint torques do not contribute directly to the bat head speed. Therefore, the purpose of this study was to make clear the functional roles of the lower limb joint torques considering the cumulative effect of exerting joint torques. The whole-body with bat was modelled as a system of sixteen-rigid linked segments. The contributions of the lower limb joint torques to the exerting FBR torque at torso joint were quantified through dynamic contribution equation, which relates lower limb joint torques to the torso FBR torque, derived from both dynamics joint force contribution equation of whole-body system and equilibrium balance equation with respect to rotational movement of the lower trunk segment. The results obtained in this study show 1) lower limb joint torque, especially flexion/extension torque at both hip joints, is a large contributor to the generation of the torso FBR torque, and 2) lower trunk inertial force term and other terms are small contributors to the FBR torque. The development of this analytical method would enable us to quantify the contribution of the lower limb joint torques.