Hitting Kinematics for Precise Ball-Bat Contact in Collegiate

Baseball Hitters

Jun Misaki

, Takatoshi Higuchi

, Ryo Tsuchikane

, Hiromichi Saeki

and Tadao Isaka

Graduate School of Sport and Health Science, Ritsumeikan University, 1-1-1, Nojihigashi,

Kusatsu, Shiga, 525-8577, Japan

Faculty of Socio-Environmental Studies, Fukuoka Institute of Technology, 3-30-1, Wajiro-higashi,

Higashiku, Fukuoka, 811-0295, Japan

College of Sport and Health Science, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu, Shiga, 525-8577, Japan

Keywords: Baseball, Hitter, Precision, Ball-Bat Contact.

Abstract: In baseball, higher bat velocity and the bat control are required for the successful hitting. Although

kinematical factors related bat velocity have been studied, the knowledge about hitting kinematics related

ball-bat contact precision is limited. The aim of this study was to examine the hitting kinematics for precise

ball-bat contact in collegiate baseball hitters. Ten collegiate baseball field players completed 20 swings at a

ball on the baseball tee, and their joint angles were calculated. The results indicate that hitters with lower

precision in ball-bat contact might have excessive variability in joint angles in trail arm.

1 OBJECTIVES

Hitting a baseball has been described as one of the

most difficult tasks in sports. Baseball hitters should

accelerate the bat head within short duration, and

lead the bat toward the appropriate location.

Therefore, higher bat velocity and the bat control are

required for the successful hitting (Morishita et al,

2013).

A previous study showed that collegiate and

professional baseball players hit a ball on the

baseball tee with highly precise ball-bat contact.

(Higuchi et al, 2013). Although kinematic factors

related bat velocity have been studied (Welch et al,

1995; Escamilla et al, 2009; Inkster et al, 2010), the

knowledge about hitting kinematics related ball-bat

contact precision is still limited. For the coaching on

hitting precision based upon the scientific evidences,

the investigation about hitting kinematics related

precise ball-bat contact should be required.

This study aims to examine the hitting kinematics

for precise ball-bat contact in collegiate baseball

hitters.

2 METHODS

2.1 Participants

Ten male collegiate baseball field players (Age: 19.0

±0.0 years, Height: 1.778±0.051 m, Body mass:

75.3±7.3 kg) were participated in this study. The

mean length of their baseball experience was 11.1 ±

2.2 years. Before the experiment, informed consent

was obtained from all participants for their

participation in this research. The Ethics Committee

on Human Research of Ritsumeikan University

approved this study.

2.2 Experimental Procedures

The experiment was conducted in the indoor

laboratory. A target board was set in front of the

participants (Figure 1). The subjects were instructed

to hit a ball on the baseball tee toward the center

point of the target board. After sufficient warm-up

and practice hitting, the participants performed two

sets of 10 trials. The heights of baseball tee were

determined as the heights of anterior superior iliac

spine in each subject.

Misaki, J., Higuchi, T., Tsuchikane, R., Saeki, H. and Isaka, T.

Hitting Kinematics for Precise Ball-Bat Contact in Collegiate Baseball Hitters.

In Extended Abstracts (icSPORTS 2016), pages 31-34

Figure 1: Experimental setting.

2.3 Data Collection

Movements of the bat and ball were recorded using

two synchronized, high-speed video cameras

(MEMRECAM fx-K5, Nac Image Technology,

Japan)

with 1000 frames/sec. Forty-two reflex

markers were attached to the body landmark of

participants and baseball bat. Those markers were

captured by motion capture system (MAC 3D,

Motion Analysis Corporation, USA) at 500Hz.

2.4 Data Processing

The image data of bat head, bat grip, and ball center

were manually digitized using motion analysis

software (Frame Dias V, DKH, Japan). The three-

dimensional coordinates were obtained with the

direct linear transformation method. The image at

the instant of ball-bat contact was used for the

analysis. We defined the area formed by standard

deviation in short and long axes on the bat

coordinate as an index of precision at ball-bat

contact (Figure 2).

To smooth the motion capture data, marker

coordinates were filtered using a lowpass

Butterworth digital filter with a cutoff frequency of

13.3 Hz (Welch et al, 1995; Inkster et al, 2010). We

used a rigid link model that contains two trunk

segments and 12 upper/lower joints. Therefore, 30

angles were calculated as kinematic variables of the

body. Segments/joints (angles) were, thorax and

pelvis (anterior/posterior tilt, right/left tilt, right/left

rotation), shoulder (flexion/extension,

abduction/adduction, internal/external rotation),

elbow (flexion/extension, pronation/supination),

wrist (palmar/dorsi flexion, radial/ulnar deviation),

hip (flexion/extension, abduction/adduction,

internal/external rotation), knee (flexion/extension),

ankle (dorsi/plantar flexion), respectively. Following

the joint angle calculation, coefficient of variation

(CV) in each angle was worked out as a kinematical

variable. All processing of motion capture data were

performed using Visual 3D (C-Motion, Inc., USA).

Figure 2: Index of precision at ball-bat contact.

2.5 Visualization of Results

We visualized the CV value of each angle in a

forward swing phase. The forward swing phase is

defined as the phase between swing initiation and

ball-bat contact. The data were then time-normalized

to 100% using a cubic spline (Kawamura et al,

2008). Visualization process was conducted using

Matlab 2014a (Mathworks, Inc., USA).

3 RESULTS

Figure 3 shows the results of the visualization of CV

(%) in forward swing phase of all participants (P1 to

P10). In figure 3, the degrees of CV were shown as

heat maps. Red zones indicate higher value, blue

ones represent lower value. Graphs of P1 to P10

were in order based on the index of precision at ball-

bat contact; P1 was the most precise hitter; P10 has

the lowest precision in all participants.

In particular, higher or medium values of CV

were observed in the trail shoulder, elbow, and wrist

of P5 to P9. Additionally, CV in thorax and pelvis

rotation showed medium or higher value in early to

intermediate phase of swing across all participants.

icSPORTS 2016 - 4th International Congress on Sport Sciences Research and Technology Support

Figure 3: Visualization of coefficient of variation in forward swing phase. (Normalized time of 0 % indicates the swing

initiation and normalized time of 100 % indicates the ball-bat contact).

4 DISCUSSION

A previous research demonstrated that the angles of

elbow and wrist in trail arm have major change in

the forward swing phase (Kawamura et al, 2008).

According to this knowledge, it is considered that

excessive variability of angle in trail arm may

disturb the precise bat control. Therefore, hitters

with lower precision in ball-bat contact might have

excessive variabilities in joint angles in trail arm.

On the other hand, CV in thorax and pelvis

rotation showed medium or higher value in early to

intermediate phase of swing regardless of the index

of precision in ball-bat contact. This result suggests

that variability of thorax and pelvis rotation in early

phase of the swing is less critical to hitting precision.

Earlier studies showed that hitting kinematics

varies with skill level and age of players (Escamilla

et al, 2009; Inkster et al, 2010). Therefore, further

studies are required to investigate the hitting

kinematics relating precision at ball-bat contact in

various skill levels and ages.

ACKNOWLEDGEMENTS

We would like to appreciate for the all participants

and experimenters of this study. Additionally, we

would like to thank Haruka Shoda, for his invaluable

advices on the visualization of results in this

research.

REFERENCES

Higuchi, T., Nagami, T., Morohoshi, J., Nakata, H.,

Kanosue, K., 2013. Disturbance in hitting accuracy by

professional and collegiate baseball players due to

intentional change of target position. Perceptual and

Motor Skills, 116(2), 627-639.

Morishita, Y., Hirano, Y., Yanai, T., 2015. Mechanical

factors for determining the bat-head speed and the

orientation of the bat at ball impact in baseball hitting.

Japanese Journal of Biomechanics in Sports and

Exercise, 19(4), 201-215.

Welch, C., Banks, S., Cook, F., Draovitch, P., 1995.

Hitting a baseball: a biomechanical description.

Journal of Orthopaedic and Sports Physical Therapy,

22(5), 193–201.

Escamilla, RF., Fleisig, GS., DeRenne, C., Marcus KT.,

Claude TM, Rodney I., Edward B,

James RA., 2009.

A comparison of age level on baseball hitting

kinematics, Journal of Applied Biomechanics, 25(3).

210–218.

Inkster, B., Murphy, A., Bower, R., Watsford, M., 2011.

Differences in the kinematics of the baseball swing

Thorax

Pelvis

Lead Shoulder

Trail Shoulder

Lead Hip

Trail Hip

P1 P2 P3 P4 P5 P

P7 P8 P9 P10

Normarized Time [% ]

0　 50　 100 0　 50　 100 0　 50　 100 0　 50　 100 0　 50　 100 0　 50　 100 0　 50　 100 0　 50　 100 0　 50　 100 0　 50　 100

0　　　　 1　　　　 2　　　　3

P1 P2 P3 P4 P5 P

P7 P8 P9 P10

Normarized Time [% ]

0 50 100　0 50 100 0 50 100 0 50 100 0 50 100 0 50 100 0 50 100 0 50 100 0 50 100 0 50 100

0　　　　 1　　　　 2　　　　3

Lead Elbow

Lead Wrist

Trail Elbow

Trail Wrist

Lead Knee

Lead Ankle

Trail Knee

Trail Ankle

value

Hitting Kinematics for Precise Ball-Bat Contact in Collegiate Baseball Hitters

between hitters of varying skill. Medicine and Science

in Sports and Exercise, 43(6), 1050-1054.

Kawamura, T., Shimada, K., Takahashi, K., Morimoto, Y.,

Koike, S., Ae, M, 2008. Comparison of kinematics of

upper limb motion in the baseball batting between

high and low groups in the bat speed. Japan Journal of

Physical Education, Health and Sport Sciences, 53,

423–438.

icSPORTS 2016 - 4th International Congress on Sport Sciences Research and Technology Support