An Analysis of Timing in Softball Hitting
Yuichi Hirano
Department of Sports Sciences
College of Arts and Sciences

University of Tokyo

Abstract

The purposes of this study were to determine the time when female softball hitters started
to shift the center of gravity of the body (CG) and to examine how they reacted to the changing speed of a pitched ball. Four female softball hitters, 2 ski[ed (S) and 2 unskilled (U), participated in this study. A female softball pitcher was requested to throw an official ball ateach one of three rates of ball speeds (fast, medium, and slow), which were randomly delivered
to a hitter. In order to record the ground reaction force exerted by each foot, subjects wererequested to put one of their feet on each of two force-platforms. At the same time, hitting
motiou was filmed from the front by a cine-camera (1m fs/sec). Pitched balt speed (BS) (m/sec),
duration of swing (ST) (sec), and the speed of a bat (BtS) (m/sec) were calculated from thecinematographic data. It was shown that the skilled tended to have slightly shorter ST thanthe unskilled. No signiEcant correlation coefficient was found between ST and BS among allsubjects, whereas the skilled showed greater BtS. Each foot force applied on a respectiye
force-platform in the pitcher-catcher direction (F) was used for the analysis of timing. Using
the obtained force curves, following calculations were made ; 1) duration from X to impact (X-IP)(sec), in which X was designated at the point from where the piled F curves branched out,2) distance from the position of a ball at X to that at the impact: (BP)(m): Bs(m/sec) x X-IP(sec).
The values of X-IP were 0.42t0.093 sec for 51, 0.36t0.011 sec for 52, and 0.34t0.083 sec forUl, respectively. The skilled tended to have longer X-IP. It was also found that the greater
BS was, the shorter X-lP the all subjects had. However, there was no correlationship between
BP and BS. ln order to clarify the pattern of F at each BS, F curves were pited using theimpact point as a trigger. In the skilled, the f,attern was varied before the start of swing but
it was almost the same after the onset of sn'ing. On the contrary, the unskilled showedalmost the same pattern before starting the swing but it varied after starting the swing.
Key Words; softball hiltilg, ground reaction fmce, analtsis of timing.

2Introduction

It has ever been stated that hitting a ball in all sports is one of the most difficult skills tomaster, for hitting has two aspects, i.e. sensory-perception and motor-responseJ and a hittermust integrate those in a short time. The former aspect consists of eye-body coordination. lntracking a pitched ball visually, a hitter must predict the locus of the ball and at a certain
point in its flight one has to decide whether to swing at or not. Furthermore, if one decides
to swing, he or she must adiust exact point of time when he or she starts his or her hitting
motion in response to the ball speed, namely, with proper timing. On the other hand, thelatter aspect involves body-bat coordination. By summing up the velocities of the movementsof the related body segments, a hitter must generate maximal bat speed in order to hit theball with a greater impact.
The purpose of this study was to determine the time when ferrale softball hitters started
to shift the center of gravity of the bodr' (CG) and to examine how they reacted to the chang'
ing speed of a pitched ball.
Table 1. Subjects' physical characteristics aDd hitting careers.
SubiSex

Sl

F
FF

S2

Ul
U2

「Age(yrs)

Ht(cm)

Wt(k,{)

Hitting Ave

21156 00 286

20170 00 292

18159 419164 6Fig. I Experimental setup

3Procedure

Four female softball hitters, 2 skilled (S) and 2 unskilled (U), participated in this study.
The skilled were the players who regularly played in an intercollegiate softball league, while
the unskilled were not pla!'ing in an-v official games but belonged to a college softball team.
They provided their informed consents. The subjects' physical characteristics and hitting careers are presented in Table 1.
A female softball pitcher was requested to throw an official ball (177. 19-198.45 g) in a manner determined by rule at each one of three rates of ball speeds (fast, medium, and slow), whichwere randomly delivered to a hitter. In order to record the rnagnitude and direction of theground reaction forces exerted by each foot, subjects were requested to stand on two forceplatforms (Kistler Co.), the left leg on the pitcher's side and the right leg on the catcher's side.
At the same time, hitting motion was 6lmed from the front by a cine-camera (100 fs/sec,Photosonics 16-1P) (Fig. 1). l'ilm and force-platform data were syncronized by an electric signal.
Each subject tried to hit a ball about 15 times. In all trials, evaluation of timing in hitting(early, proper, and late) was made by tu,o experts in softball so as to select hitting trials withproper timing for analytical use.
Following items were calculated from the cinematographic data obtained.
1. pitched ball speed immediatel-y before impact (RS) (m/sec)
2. duration of swing from the onset of the forward movement of a bat to its impact on theball (ST) (sec)
3. the speed of a bat (its head pafi) immediately before the impact (BtS) (m/sec)
Ｘ ＩＩ Ｉ ←IP IPIP

right FOOt

Fig. 2 The glound reaction fotces exerted by each foot. X represetrts the poiDt atwhich piled F curves begid to separate.

4

Each foot force applied on a respective force-platform in the pitcher-catcher direction (F)was used for the analysis of timing. Using the obtained force curves which were syncronizedwith cinematographic data, following calculations were made.
1. duration from X to impact (X-IP) (sec), in which X was designated at the point from

where the piled F curves branched out (Fig.2).
2. distance from the position of a ball at X to that at the impact, in which following
equation was used ; BP(m):Bs(m/sec) x X-IP(sec)ResultgThree rates of RS delivered by pitcher were significantly different (p<0.01) from one an'Table 2

Pitched ba1l speed(BS)mediumfastBS

22 83*

18 18

14 39拿(m/sec)+2 46± 1 62± 139

mean ts. d.

*; p<0.01 when different from the mediumball speed.

:ギ024± 0078

"針?

Ul︱

024± 0026﹁ロポト△醒

﹁0Sl△028± 0032

コ

◆

:会◆

344■ 201

271■ 194◆

U2︲20BtS

Fig.3

ST (above) ond BtS (below). * p<0.05, "p<0.01'﹁コト◆∞ 4± 484

ｍ°68案

S2o０△◆.ate

Ｂ040

STイ ー マ ｌ ｔ︲030020

ｉ赫ｅｍｄｍ026

U2

5other (Table 2). Therefore, it *'as considered that the pitcher could rhrow the ball at thedesignated speed at her own will.
All subjects, excluding U2 who hit the ball with proper timirg only once, hit the ball pro_
perly by 50-707 of all trials.
Duration of swing (ST) is presented in Fig. 3. It was shown rhat the skilled (S1, 52)
tended to have slightly shorter time than rhe unskilled (u1, u2). No signilicant correlarion
coemcient was found between ST and B,S among all subiects, $,hereas the skilled showed
greater bat speed (BtS).
Typical foot force curves obtained from the left and the right foot for each group of subjects are shown in Fig. 4. As illustrated in the 6gure, duration of time between point X andthe impact (X-IP) was measured. The values obtained were0.42t0.093secfor51,0.36tO.0U
sec for 52, and 0.34t0.083sec for Ul, respectively. The skilled tended to have longer X-Ip.
It was also found that the greater BS was, the shorter X-IP the all subjects had. However,there was no correlationship between the position of pitched ball from the impact at point X

riaht f@t

1Fig. 4 Foot forces generated $rhen hitting. Curves were piled by using the backswing phase as a trigger point.

6(BP) ard BS.

In order to clarify the pattern of F at each BS, F curves were piled up using the impact point
as a trigger. In the skilted, the pattern was varied before the start of swing but it showedalmost the same pattern after the onset of swing. on the contrary, the unskilled showed almost
the same pattern before starting the swing but it varied after that.

l02030 (m/sec)

BS01020AS

Fig. 5 Relationships betweel BS and X-lP, and BS and BP.
of swing imPactright f@t

lert Foot

Fig. 6 Patterns of F curves according to BS. ST represents the avetage dulationof the swing. Solid line (-), dotted lifle (...), and cross (x) represent
the curves $ahen hitting slow, medium, and fast ball, respectively.

7Dicussion

In this study, it was found that in the skilled players the changes in F began to appear
sooner in the locus of the pitched balt than in the unskilled. It seemed to suggest that theskilled could differenciate BS earlier and could adjust the movement of CG to BS more adequately than the unskitled. On sensory-perceptual problem of hitting, the reaction time, whichis the time between the presentation of visual stimulus and the beginning of the bat swing,
has always been the point of argument. When investigating reaction time in swinging to agiven stimulus, Slater-Hammel, A.T. et al. reported the values of 0.206 sec as simple reactiontime(e) and 0.293 sec as choice reaction time('o). According to Breen, J.L.o) and Race D. E.(6),swinging of a bat lasted 0.19-0.28 sec. Therefore, it might be estimated that the total timerequired in swinging would be the sum of reaction time and swinging time, i.e. the total of0.4-0-5 sec. In considering very short flight time of the pitched ball from the mound to thehome plate, which is 0.43-0.58(?), a hitter must predict the course and the speed of the ballimmediately after the release of the balt by the pitcher. Hubbard, A. W. et al.(s) asserted thatin hitting situation the hitter's step and "wind up" for the swing must occur urhile thesensory-perceptual process was under way. Glencross, p. L. et al,(r) also claimed that hittermust anticipate the direction and position of the ball very early in its flight, a'Id that hitter
would have to initiate part of the swing prior to delivery.
In following the line of these assertions, as the skilled in this study started their swinging
movement earlier, they were said to be taking good stance in hitting a ball proprly. Whilein this study BP was calculated by using the balt speed immediately before the impact and it
was found to be at 5-8m from the impact, i.e. at about a half way between the pitcher,smound and the home plate, the actual BP at which swing motion started may be considered alittle further than that from the impact. Therefore, in this study it was suggested that ahitter was not judging the ball speed immediately after the release of the ball.
In the skilled, F was reconformed before the start of swing, and as repnrted by Messier,
R.G. et al.o), a rapid increase in bat velocity directed toward the pitched ball began 0.12sec
prior to the contact point. Therefore, it was considered that the skilted did control their cG
continuously before starting the s\ring. Although they started to shift their cG sooner thanthe uoskilled, when hitting off.speed pitches, they appeared to once lift and then land theirleft foot and decelerate the movement of their cG so that proper timing might be maintained
throughout the swing.
The skilled showed desirable body control before the start of swing and almost the same
pattern of F was maintained in spite of changes in BS after starting the swing. Their leftfoot seemed to be firmly landed when they tried to make a good impact on all t,'pes of pitches.

It was considered that, in doing so, they generated greater BtS. On the contrary, the unski[edshowed different pattern of F during their swing, with which they frequently hit the ball tate.
So, it was considered that, even if they had proDer bat control, they seemed to be considerabty

sacrificing their BtS.

8References(l) Breen, J.L.: What Makes a Good Hitter? JOIIPER, 38: 36-39' 1967.

(2) Glencross, D.J. and B.J. Cibich: r\ Decision Analysis of Games Skills. r\ust. J, Sports Medicine'I | 72-75, l9?7 .
(3) Hubbard, A. W. and C. N. Seng : Visual Movements of Batters. Res. Quart', 25 | 42'57 ' 1951 '(4) Messier, S.P. and M.G. Owen: Bat Dynamics of Female Fast Pitch softball Batters. Res. Qualt..
s5: 141 145. 1984.

(5) Miller, R.G. and c.T. shay: Relationship of Reaction Time to the speed of a softball. Res. QuaIt.,
35: 433-437. 1964.
Race, D.E.: A Cinematoglaphic and Mechanical Analysis of the External ]\,ovements lnvolved in
Hittirg a Uaseball Effectively. Res. Quart., 32: 394-40't, 1961.

Scott, M.G.: Aflal)-sis of Human Motion New York City: F.S. Crofts and Co', 19'15'
Selin, C.: An Analysis of the Aerodvnamics of Pitched Baseballs. Res' Quart', 30: 232-2'10' 1959'
Slater-Ilammel, A. T. and R. L. Stumpner: Batting Reaction-Time Res Quart ' 2l : 35:]-356' 1950'
slater-Hammel, A.T. and R.L. Stumpner: Choice Batting Reaction-Time. Res. Quart..22.377 380,
1951.