行政院國家科學委員會專題研究計畫 成果報告
壘球推擊技巧之生物力學分析(第 2 年)
研究成果報告(完整版)
計 畫 類 別 ： 個別型 計 畫 編 號 ： NSC 98-2410-H-028-003-MY2 執 行 期 間 ： 99 年 08 月 01 日至 100 年 07 月 31 日 執 行 單 位 ： 國立臺灣體育學院運動健康科學學系 計 畫 主 持 人 ： 張怡雯 共 同 主 持 人 ： 楊賢銘、許弘昌 計畫參與人員： 學士級-專任助理人員：謝秀美 報 告 附 件 ： 出席國際會議研究心得報告及發表論文 公 開 資 訊 ： 本計畫可公開查詢中 華 民 國 100 年 10 月 31 日
中文摘要： 壘球推擊為左打者經常使用的打擊技巧，在打擊過程中，經由 左腳的預先跨步，可拉近打者與一壘的距離，因而使成功踏上 一壘的機會大增，因此，本研究的目的為比較壘球推擊與一般 打擊在軀幹旋轉的生物力學上的差異。共有 10 位女性大學甲組 壘球選手參與實驗，皆為左打者，利用 Vicon 三維動作分析系 統，收集黏貼於身體上與球棒的反光標記，用以分析軀幹旋轉 參數。結果發現，在打擊預備期時，推擊比一般打擊有較小的 軀幹後旋產生，而在跟隨動作期時，一般打擊比推擊有較大的 軀幹前旋，在擊球瞬間，推擊和一般打擊之間並無軀幹旋轉位 置的顯著差異出現。結果顯示，使用此二種不同的打擊技巧， 並不會影響打擊瞬間時軀幹相對於本壘板之位置。然而，對於 影響打擊表現的因子而言，推擊的球棒線性速度與擊出球速， 比一般打擊還要慢，同時，推擊的軀幹旋轉速度也比一般打擊 來的小，因此，壘球選手選擇使用推擊技巧時，除了瞭解推擊 時打者位置與一壘較近的優勢之外，也必須考量球速減低、限 制預備期軀幹後旋與跟隨動作期軀幹前旋、以及軀幹旋轉速度 變慢等運動生物力學上的改變，對打擊所造成的可能影響。 英文摘要： A slap hit is used for the left-handed batters who can get a running
start before hitting the ball by using the left-side running slap. The purpose of this study was to compare the biomechanical difference of the torso twist between the slap and ordinary hit. Ten female left-handed college softball batters participated in this study. A VICON 612 motion analysis system was used to analyze the motion of the players. Surface reflective markers were placed on selective anatomical landmarks for each participant. Slap hits showed less backward rotation of the torso during wind-up phase while ordinary hits showed more forward rotation of the torso during
follow-through phase. There was no significant difference between slap and ordinary hits at impact. The findings of this study suggested that torso rotational position at bat-ball contact was not affected by various hitting technique. Moreover, bat linear velocity, batted ball velocity and angular velocity of torso twist were decreased in slap hit compared to ordinary hit. The findings of this study suggested that in addition to the advantage of the hitter with more close
position to first base, the possible disadvantage of slower batted ball velocity, reduced angular velocity of torso twist, the restricted torso backward twist in wind-up phase and limited torso forward twist in follow-through phase should be taken into consideration during performing the slap hit.
中文摘要
壘球推擊為左打者經常使用的打擊技巧，在打擊過程中，經由左腳的預先跨步，可拉 近打者與一壘的距離，因而使成功踏上一壘的機會大增，因此，本研究的目的為比較壘球推 擊與一般打擊在軀幹旋轉的生物力學上的差異。共有 10 位女性大學甲組壘球選手參與實驗， 皆為左打者，利用 Vicon 三維動作分析系統，收集黏貼於身體上與球棒的反光標記，用以分 析軀幹旋轉參數。結果發現，在打擊預備期時，推擊比一般打擊有較小的軀幹後旋產生，而 在跟隨動作期時，一般打擊比推擊有較大的軀幹前旋，在擊球瞬間，推擊和一般打擊之間並 無軀幹旋轉位置的顯著差異出現。結果顯示，使用此二種不同的打擊技巧，並不會影響打擊 瞬間時軀幹相對於本壘板之位置。然而，對於影響打擊表現的因子而言，推擊的球棒線性速 度與擊出球速，比一般打擊還要慢，同時，推擊的軀幹旋轉速度也比一般打擊來的小，因此， 壘球選手選擇使用推擊技巧時，除了瞭解推擊時打者位置與一壘較近的優勢之外，也必須考 量球速減低、限制預備期軀幹後旋與跟隨動作期軀幹前旋、以及軀幹旋轉速度變慢等運動生 物力學上的改變，對打擊所造成的可能影響。 關鍵詞：推打、一般打擊、軀幹旋轉、擊出球速、球棒速度Abstract
A slap hit is used for the left-handed batters who can get a running start before hitting the
ball by using the left-side running slap. The purpose of this study was to compare the biomechanical
difference of the torso twist between the slap and ordinary hit. Ten female left-handed college
softball batters participated in this study. A VICON 612 motion analysis system was used to analyze
the motion of the players. Surface reflective markers were placed on selective anatomical landmarks
for each participant. Slap hits showed less backward rotation of the torso during wind-up phase
while ordinary hits showed more forward rotation of the torso during follow-through phase. There
was no significant difference between slap and ordinary hits at impact. The findings of this study
suggested that torso rotational position at bat-ball contact was not affected by various hitting
technique. Moreover, bat linear velocity, batted ball velocity and angular velocity of torso twist
were decreased in slap hit compared to ordinary hit. The findings of this study suggested that in
addition to the advantage of the hitter with more close position to first base, the possible
disadvantage of slower batted ball velocity, reduced angular velocity of torso twist, the restricted
torso backward twist in wind-up phase and limited torso forward twist in follow-through phase
should be taken into consideration during performing the slap hit.
Introduction
The excellence of sport performance has become one of the major goals of government
policy in Taiwan. It is essential to longitudinally monitor the biomechanical characteristics of sports
in order to reach the optimal performance. Softball is one of the sports that Taiwan has showed
great success in international competitions (龍炳峰, 2006). Whilst the sport of softball has achieved
worldwide popularity over the last 100 years, a consideration of the scientific principles
underpinning softball is in its infancy (Flyger, et al., 2006).
Softball is a variation of baseball that uses a softer and larger ball, a smaller and lighter bat,
and a smaller playing field. Various motor skills are associated with softball, such as pitching,
batting and fielding. Excellent batting ability is one of the most important factors to win the
competition. A powerful bat swing requires to be generated by using ground reaction force and
transferring the force through biomechanical links of the motor segments in baseball hitting
(Katsumata, 2007). Several biomechanical researches regarding ordinary (normal) hitting have been
reported in previous studies. Tabuchi et al. (2007) found that the bat head was at maximum speed at
impact when stationary balls of standard weight were used. Inkster et al. (2011) found that
high-caliber hitters had a higher velocity (36.8 m/s) and lead elbow maximum angular velocity
while low-caliber hitters had a lower velocity (33.8 m/s) and lead elbow maximum angular velocity.
Nicholas et al. (2003) compared the bat kinematics difference between metal bats and wooden bats
and found that metal bats produced a higher liner bat tip velocity than wooden bats because of
lower swing moment of inertia in metal bats. There have been numerous baseball hitting studies
published in literatures. In comparison, softball batting has received minimal attention in the sports
science literature and a significantly smaller amount has been spent on the needs of the softball
athlete (Welch et al., 1995).
Baseball/softball hitting is an open kinetic chain movement (Nicholls, 2003). The initiation
of hitting is from the most proximal segment, the lower limbs, to the most distal part, the bat
(Putman, 1993). In order, the connection between the proximal and distal segments should be
adopted in the course of a typical game in order to step to first base as quickly as possible. In
addition to the ordinary hit, a slap hit is a unique technique legally and frequently used in softball
game. A slap hit is used only for the left-handed batters who can get a running start before hitting
the ball by using the left-side running slap. The batter is already several steps closer to the first base.
Although slap hit seems to have its advantage in hitting competition, the biomechanical
characteristics of softball slap hit is needed to be quantified to understand the kinematic difference
from ordinary hit.
The torso is the kinetic linkage between the upper and lower limbs, and its sequential motion
in batting has been considered to transfer power and generate synergy between the lower and upper
limbs (Morishita, 2010). Welch et al. (1995) indicated that a hitter starts the swing with a weight
shift toward the rear foot and development of torso twist. Escamilla et al (2009b) indicated that
adult hitters maintained a more open pelvis position at lead foot off ground and maintained a more
open upper torso position when the hands started to move forward and a more closed upper torso
position at impact. Accordingly, investigating the hitting movement in term of torso twisting by
focusing on the torso twist is a useful way for understanding the hitting kinematics. There have
been lots of researches about baseball hitting in previous studies, very little is known about the
twisting motion of the torso in slap hit techniques. Therefore, the purpose of this study was to
compare the difference of the torso twist between the slap and ordinary hit. The hypothesis of this
study was that there will be a significant difference between slap hit and ordinary hit, and the batted
ball velocity and the linear bat velocity will be compensatory to the difference between two hitting
techniques.
Methods
ParticipantsTen female left-handed college softball batters participated in this study (age: 19.8±1.0 years;
height: 160.7±3.2 cm; weight: 58.5±3.4 kg; hitting experience: 7.3±1.9 years). Before the
consent has been signed by each participant. The research protocol has been approved by the ethical
committee of National Taiwan College of Physical Education.
Equipments and Protocol
A VICON 612 motion analysis system (Oxoford Metrics Limited.) with six digital cameras
(250 Hz) was used to analyze the motion of the players. Surface reflective markers were placed on
selective anatomical landmarks for each participant, including the acromion process, the spinal
processe of the 8th thoracic spine and the anterior superior iliac spines. One surface marker was
placed on the bat tip to measure the bat head velocity. The ball was wrapped with reflective paper to
estimate the batted ball velocity. Each participant performed three trials of each hitting technique
(ordinary hit and slap hit) from a batting tee.
Data Analysis
Softball batting consist of a wind-up, swing and follow-through phases (Fig 1). For the
kinematic analysis, the swing motion in softball batting was divided into several events, including
start of take back, right toe off, right toe on, swing start, impact and swing end (Tago, 2010). Slap
hits had two additional instants during the wind-up phase, left toe off and left toe on, to prepare the
players with anticipatory running start.
The torso twist was defined as the angle between the direction of trunk segment in the
frontal plane and the direction of the base toward the pitcher (Morishita, 2010). In this study,
positive angle denoted a rotation to right (forward twist) and negative angle denoted a rotation to
left (backward twist), while zero degree meant the torso was parallel to the direction of the base
toward the pitcher. The batting time for each phase was recorded and the instant timing was
measured and normalized as 100% of batting cycle.
Statistical Analysis
The testing variables were the batted ball velocity, the bat head velocity, the batting timing,
the torso twist angle and its corresponding angular velocity at each specific instant in head, shoulder
girdle, C7, T8, L5 and pelvis. Paired-t test was used to compare the difference for each analyzed
parameter between ordinary hit and slap hit (SPSS, V13.0).
Results
Velocity and Timing
The batted ball velocity and the bat head velocity were shown in Table 1. There were
significant difference between ordinary hit and slap hit (p<0.005). Ordinary hit had significantly
faster batted ball velocity and bat head velocity than slap hit.
Table 1: Batted ball velocity and bat head velocity in ordinary hit and slap hit. m/sec Ordinary Hit Slap Hit P value Batted ball velocity 19.94±3.06 16.81±3.88 0.003* Bat head velocity 22.52±2.61 18.46±3.30 0.000* *Significant difference (p<0.05).
Batting time and timing at each instant was shown in Table 2. Instant timing of right toe on
had significant difference between ordinary hit and slap hit (p<0.01). Slap hit showed significantly
faster right toe on than ordinary hit. No significant difference between ordinary hit and slap hit was
Table 2: Batting timing of each phase in ordinary hit and slap hit.
Ordinary Hit Slap Hit P value
Time (ms) Total 436.58±69.69 440.50±81.26 0.848 Wind up 280.83±75.80 299.42±79.76 0.375 Swing 65.33±14.75 14.92±115.03 0.152 Follow through 90.42±37.78 126.17±113.30 0.296 Timing at each instant (%) R toe off 38±13.7 31±12.1 0.159 R toe on 59±9.1 48±10.3 0.007* Swing start 63±10.6 67±7.3 0.292 Impact 79±9.1 71±25.9 0.291 *Significant difference (p<0.05).
Torso Twist Angle
Angle at each Hitting Instant
Head
The torso twist angles of the head in ordinary hit and slap hit were shown in Fig 2. Head
position was not evidently changed until impact. Significant differences in head were found at the
instants of the right toe off, right toe on and swing start (p<0.05). Slap hit showed more forward
rotation than the ordinary hit during the mid-wind-up phase. However, there was no significant
difference at impact.
Shoulder Girdle
The torso twist angles of the shoulder girdle in ordinary hit and slap hit were shown in
Figure 3. Significant differences in shoulder girdle were found at the instants of the start of take
back, right toe off, right toe on, swing start and swing end (p<0.05). Slap hit showed less torso
backward rotation than the ordinary hit during the wind-up phase and less torso forward rotation
during follow-through phase. However, there was no significant difference at impact.
Figure 3: Torso twist angle of the shoulder girdle in ordinary hit and slap hit (* denoted paired t test, p<0.05 ).
C7
The torso twist angles of the C7 in ordinary hit and slap hit were shown in Figure 4.
Significant differences in C7 were found at the instants of the start of take back, right toe off, right
toe on, swing start and swing end (p<0.05). Slap hit showed less torso backward rotation than the
ordinary hit during the wind-up phase and less torso forward rotation during follow-through phase.
Figure 4: Torso twist angle of the C7 in ordinary hit and slap hit (* denoted paired t test, p<0.05 ).
T8
The torso twist angles of the T8 in ordinary hit and slap hit were shown in Figure 5.
Significant differences in T8 were found at the instants of the start of take back, right toe off, right
toe on and swing start (p<0.05). Slap hit showed less torso backward rotation than the ordinary hit
during the wind-up phase. However, there was no significant difference at impact and swing end.
Figure 5: Torso twist angle of the T8 in ordinary hit and slap hit (* denoted paired t test, p<0.05 ).
L5
The torso twist angles of the L5 in ordinary hit and slap hit were shown in Figure 6.
Significant differences in L5 were found at the instants of the start of take back, right toe off, right
during the wind-up phase. However, there was no significant difference at impact and
follow-through phase.
Figure 6: Torso twist angle of the L5 in ordinary hit and slap hit (* denoted paired t test, p<0.05 ).
Pelvis
The torso twist angles of the pelvis in ordinary hit and slap hit were shown in Figure 7.
Significant differences in pelvis were found at the instants of the start of take back, right toe off,
right toe on, swing start and swing end (p<0.05). Slap hit showed less torso backward rotation than
the ordinary hit during the wind-up phase and more torso forward rotation during follow-through
phase. However, there was no significant difference at impact.
Figure 7: Torso twist angle of the pelvis in ordinary hit and slap hit (* denoted paired t test, p<0.05 ).
Peak Angle
Maximum forward torso twist angle in ordinary hit and slap hit was shown in Table 3. There
was a significant difference between ordinary and slap hit in shoulder girdle, C7 and pelvis (p<0.05).
Ordinary hit had significantly greater forward rotation in shoulder girdle and C7 than slap hit while
slap hit had significantly greater forward rotation in pelvis than ordinary hit.
Table 3: Maximum forward torso twist angle in ordinary hit and slap hit. (* denoted paired t test, p<0.05)
(°) Ordinary Hit Slap Hit P value Head 83.76 ± 14.47 88.40 ± 17.06 0.476 Shoulder Girdle 143.27 ± 13.65 128.46 ± 13.03 0.026* C7 136.41 ± 11.06 123.16 ± 13.00 0.040* T8 127.39 ± 7.87 122.84 ± 9.70 0.248 L5 107.83 ± 9.59 111.66 ± 9.86 0.194 Pelvis 104.66 ± 6.64 113.21 ± 7.08 0.011*
Maximum backward torso twist angle in ordinary hit and slap hit was shown in Table 4.
There was a significant difference between ordinary and slap hit in shoulder girdle, C7, T8, L5 and
pelvis (p<0.05). Ordinary hit showed significantly more backward rotation than slap hit in all torso
segments (p<0.05). However, no significance was found in head.
Table 4: Minimum torso twist angle in ordinary hit and slap hit. (* denoted paired t test, p<0.05) (°) Ordinary Hit Slap Hit P value Head 20.17 ± 12.98 25.58 ± 14.59 0.165 Shoulder Girdle -50.67 ± 10.44 -34.61 ± 14.41 0.001* C7 -39.45 ± 12.54 -25.48 ± 13.20 0.005* T8 -41.01 ± 11.25 -24.95 ± 16.57 0.000* L5 -35.87 ± 9.45 -20.02 ± 11.44 0.000* Pelvis -32.70 ± 7.47 -17.23 ± 10.28 0.000* ROM
Range of motion (maximum angle –minimum angle) in ordinary hit and slap hit was shown
in Table 5. There was a significant difference between ordinary and slap hit in shoulder girdle, C7,
T8 and L5 (p<0.05). Ordinary hit had significantly greater ROM than slap hit. No significance was
found in head and pelvis.
Table 5: ROM of torso twist in ordinary hit and slap hit. (* denoted paired t test, p<0.05) (°) Ordinary Hit Slap Hit P value Head 63.59 ± 19.46 62.82 ± 15.17 0.910 Shoulder Girdle 193.94 ± 20.31 163.07 ± 15.56 0.000* C7 175.86 ± 14.93 148.63 ± 9.74 0.000* T8 168.40 ± 16.17 147.79 ± 16.71 0.000* L5 143.70 ± 15.19 131.68 ± 13.13 0.009* Pelvis 137.36 ± 12.87 130.44 ± 11.82 0.068 Angular Velocity At Impact
Angular velocity at impact in ordinary hit and slap hit was shown in Table 6. There was a
significant difference on the angular velocity at impact for all segments, except L5 (p<0.05).
Ordinary hit had significantly greater angular velocity than slap hit in head, shoulder girdle, C7, T8
and pelvis. It was obvious that angular velocity was getting faster from proximal (lower segment,
pelvis; 255.2 m/s for ordinary hit; 204.6 m/s for slap hit) to distal (upper segment, shoulder girdle;
534.3 m/s for ordinary hit; 394.2 m/s for slap hit).
Table 6: Torso twist velocity at impact in ordinary hit and slap hit. (* denoted paired t test, p<0.05) (°/s) Ordinary Hit Slap Hit P value Head 272.06 ± 181.27 157.75 ± 86.99 0.013* Shoulder Girdle 534.27 ± 90.55 394.19 ± 74.74 0.000* C7 493.82 ± 111.75 330.21 ± 60.60 0.000* T8 518.02 ± 110.17 338.17 ± 75.08 0.001* L5 276.97 ± 74.24 240.42 ± 76.75 0.063 Pelvis 255.22 ± 54.15 204.58 ± 53.38 0.005*
Peak Velocity
Maximum angular velocity of forward torso twist in ordinary hit and slap hit was shown in
Table 7. There was a significant difference between ordinary hit and slap hit in shoulder girdle, C7,
T8, L5 and pelvis (p<0.05). Ordinary hit had significantly greater angular velocity of forward
rotation. However, no significant difference was found in head.
Table 7: Maximum torso twist velocity in ordinary hit and slap hit. (* denoted paired t test, p<0.05) (°/s) Ordinary Hit Slap Hit P value Head 352.41 ± 224.37 268.96 ± 67.63 0.198 Shoulder Girdle 845.59 ± 124.41 616.26 ± 87.51 0.000* C7 781.19 ± 150.86 575.57 ± 61.30 0.001* T8 840.17 ± 116.37 573.62 ± 75.51 0.000* L5 655.49 ± 147.70 366.06 ± 101.56 0.000* Pelvis 588.68 ± 61.36 323.12 ± 64.56 0.000*
Timing at which maximum angular velocity of forward torso twist occurred in ordinary and
slap hit was shown in Table 8. Zero denoted maximum angular velocity occurred at impact.
Negative sign denoted maximum angular velocity occurred before impact while positive sign
denoted maximum angular velocity occurred after impact. Maximum angular velocity occurred
before impact in all torso segments except head. Significant difference was only found in shoulder
girdle (p<0.05). Maximum angular velocity occurred earlier in slap hit (-17.6 ms) than in ordinary
hit (-15.7 ms).
Table 8: Timing of max torso twist velocity in ordinary hit and slap hit (zero = the impact; negative = before impact; positive = after impact). (* denoted paired t test, p<0.05)
(ms) Ordinary Hit Slap Hit P value Head 9.90 ± 3.73 16.50 ± 46.53 0.658 Shoulder Girdle -15.70 ± 2.79 -17.60 ± 2.50 0.025* C7 -14.00 ± 7.07 -18.20 ± 1.87 0.060 T8 -13.80 ± 3.01 -16.00 ± 1.89 0.055 L5 -19.30 ± 4.62 -20.70 ± 14.98 0.786 Pelvis -21.80 ± 2.74 -17.70 ± 5.79 0.054
Discussion
Slap HitThis study investigated the torso kinematics of the slap hit. Slap hit is a softball hitting skill
with unique hitting advantage. First, the batter stands in her standard hitting position so that she
does not tip the defense. The slapper must be in position where crossover step will put her on the
lines of the front inside corner of the box (Potter et al., 2007). To execute the slap, the hitter runs
first and hits second. She starts to move when the ball leaves the pitcher’s hand. She must not
anticipate the release. If she starts too soon, she will have to stop moving to slap the ball or will be
way out of the box (楊賢銘 et al., 2007). The first step is a small jab step with the right foot,
either forward or backward. The jab step acts as a timing mechanism. The left foot crosses
aggressively over the right foot directly to the pitcher. The left foot should land on the front line of
the box on the inside corner. The right then opens slightly toward the pitcher.
A left-handed batter can get a running start before hitting the ball by using the left-side
running slap. The lefty is already several steps closer to first base (Garman, 2001). Adding a
running start puts tremendous pressure on the defense to make the play quickly. The play often
moves the defense out of position as well. To be successful, the batter should have good speed and
the ability to put the ball in play.
Bat Velocity
Bat swing velocity is a critical parameter of the baseball swing when identifying skill level
and performance between hitters (Inkster et al. 2011). In this current study, batted ball velocity was
approximately 15.7% less using a slap hit compared using an ordinary hit, while bat head velocity
was approximately 18.0% less using a slap hit compared using an ordinary hit. Escamilla et al.
(2009) investigated the bat (distal end) linear velocity at bat-ball contact in baseball hitting and the
results showed 31±4 m/s in normal grip and 28±5 m/s in choke-up grip. Welch et al. (1995)
quantified the maximum bat linear velocity (31±2 m/s) in baseball hitting. Inkster et al. (2011)
2.1 m/s). The velocity measured in previous studies (31-37 m/s) was higher than the velocity
measured in this study (23 m/s) and it might be due to the different sports (baseball vs. softball) and
different players (male vs. female).
Swing Timing
This study showed no significant difference on the time of each phase between slap hit and
ordinary hit, implying that the early stance of the right lower limb would not affect the phase timing.
However, slap hit (48% of hitting phase) showed significantly early right toe on than ordinary hit
(59% of hitting phase). No other instant timing parameter was significantly different between two
hitting skills. It was implied that the torso movement coordination of softball swing was quite close
for these two hitting skills as a consequence of the similar temporal instant, such as right toe off,
swing start and impact. Escamilla et al. (2009a) measured the time of each phase in baseball hitting.
Based on Escamilla’s definition of hitting phase, we re-calculated the phase time percentage for our
data. In this study, ordinary softball hitting had the 51.22%, 9.76% and 39.02% for stride, transition
and acceleration phase, respectively, while in Escamilla’s study, baseball hitting had the 64.0%,
12.1% and 23.9% for stride, transition and acceleration phase, respectively. It was indicated that
body coordination and movement strategy were different in baseball and softball hitting due to the
various temporal instant.
Torso Twist Angle
For upper torso (shoulder girdle), from take back to swing start, the slap hit showed less
backward rotation than the ordinary hit, indicating that the slap hit step forward with left leg during
the wind-up phase would substantially influence or limit the torso twist backward. At the end of
swing, more upper torso twist was present in the ordinary hit (more rotation to right). It would
perhaps be the outcome of higher swing velocity.
The middle and lower torso (the thorax and pelvis), showed very similar twisting patterns.
However, when examining the difference between the ordinary hit and the slap hit in the wind-up
phase, the tendency of getting greater difference was observed between the upper torso and lower
slap hit already rotated toward the direction of pitcher (26° of forward rotation) while in the
ordinary hit, the torso maintained a backward position (22° of backward rotation) to prepare the
further quick forward rotation of trunk during the swing phase.
The restricted backward torso twist in the wind-up phase and the incomplete forward torso
twist in the follow-through phase, especially in the upper torso, may be the cause of the limited bat
swing acceleration in the slap hit. This possible disadvantage should be taken into consideration in
softball batting when the batters using the slap hit, making the batter much closer to the first base.
A more closed position is assumed if the torso twist angle becomes less positive or more
negative (Escamilla et al., 2009a & 2009b). A more open position is assumed if the torso twist angle
becomes more positive. All torso segments showed open position at impact. No significant
differences at impact were found in any torso segment. It was then clear that the torso position at
bat-ball contact was not affected by various hitting techniques used prior to impact. Katsumata
(2007) demonstrated that the timing of stepping with a front foot and shifting weight forward was
modified relative to the pitch’s speed but timing variability progressively reduced up to bat-ball
contact. Thus, no matter what hitting skill is used or how fast the ball is pitched, the hitter’s
movement coordination is approaching consistent at impact.
In comparison with previous study, we found that our findings of torso twist angle were
close to Welch’s study (Table 9).
Table 9: Comparison of torso twist angle (°) between previous study and this study.
Segment Study Toe off Toe On Impact Shoulder girdle Welch (1995) -30±14 -29±16 66±22
This study -34±15 -48±12 88±12 Pelvis Welch (1995) -18±7 4±17 83±9
This study -22±10 -22±7 85±9
Timing from backward to forward rotation
forward rotation in ordinary hit and slap hit, respectively, to allow the batters to focus on the pitcher
and the pitching ball. The greatest forward rotation in head was found at swing end. The timing
from backward to forward rotation in shoulder girdle, C7 and T8 was just subsequent to swing start
in ordinary hit and slap hit. However, the timing from backward to forward rotation in L5 and pelvis
was between right toe on and swing start in slap hit, while the timing from backward to forward
rotation in L5 and pelvis was between swing start and impact in slap hit.
Velocity of Torso Twist
This study showed that ordinary hit had significantly greater angular velocity of torso twist
than slap hit at each torso segment, from shoulder girdle to pelvis except head rotational velocity,
ranging from 589 °/s to 846 °/s in ordinary hit and from 323 °/s to 616 °/s in slap hit. There was a
trend that faster velocity occurred in upper torso (distal segment, shoulder girdle) while slower
velocity occurred in lower torso (proximal segment, pelvis), indicating a segmental rotation found
during softball hitting. Escamilla et al. (2009) measured the peak pelvis angular velocity (681 °/s)
and peak upper torso angular velocity (850 °/s) in baseball hitting. Welch et al. (1995) measured the
maximum hip rotational velocity (714±76 °/s) and maximum shoulder rotation velocity (937±102 °
/s) in baseball hitting. Both above studies demonstrated quicker velocities than the velocities
measured in this study. But both studies revealed the tendency that upper torso velocity was faster
than lower torso velocity.
Instant of Bat-Ball Contact
Bat-ball contact is one of the most critical instant in baseball/softball hitting. Our comparison
between ordinary hit and slap hit showed no significant difference on torso twist angles but
significant differences on torso twist velocities (except L5). It was indicated that slap hit did not
affect the torso twist angle but might influence or inhibit the torso twist velocity. Softball players
performed these two hitting skills with the similar body coordination but with different performance
outcome at impact.
Limitation of This Study
using a batting tee. The ball pitched from the pitcher and the real field in stadium were not used in
this study. It might be different from the real satiation of the completion or practice.
Conclusion
This study investigated the torso twist in the slap hit and ordinary hit. Slap hits showed less
backward rotation of the torso during wind-up phase while ordinary hits showed more forward
rotation of the torso during follow-through phase. There was no difference between slap and
ordinary hits at impact. The findings of this study suggested that torso rotational position at bat-ball
contact was not affected by various hitting technique. The restricted torso backward twist in
wind-up phase and limited torso forward twist in follow-through phase should be taken into
consideration during the slap hit. The numerous differences in kinematics and temporal parameters
between ordinary hit and slap hit suggest that hitting mechanics are different between these two
hitting skills.
References
楊賢銘、陳汝俊、陳鳳盈、張榮顯、姜榮彬。2007 年日本盃國際女子壘球賽情蒐分析。中華 民國壘球協會，2007 年 11 月。 龍炳峰。臺灣女子壘球參與國際運動賽會之研究(1965-2005)。體育學報，第 39 卷 4 期， 179-190 頁，2006。Escamilla RF, Fleisig GS, DeRenne C, Taylor MK, Moorman CT, Imamura R, Barakatt E, Andrews
JR (2009a). Effect of bat grip on baseball hitting kinematics. Journal of Applied
Biomechanics, 25, 203-209.
Escamilla RF, Fleisig GS, DeRenne C, Taylor MK, Moorman CT, Imamura R, Barakatt E, Andrews
JR (2009b). A comparison of age level on baseball hitting kinematics. Journal of Applied
Biomechanics, 25, 210-218.
prevention. Sports Medicine. 36(9):797-816, 2006.
Garman J. Softball skills & drills. Human kinetics, Champaign, IL, USA, pp179-192, 2001.
Inkster B, Murphy A, Bower R, Warsford M (2011). Differences in the kinematics of the baseball
swing between hitters of varying skills. Medicine & Science in Sports & Exercises, 43(6),
1050-1054.
Katsumata H (2007). A functional modulation for timing a movement: a coordinative structure in
baseball hitting. Human Movement Science, 26, 27-47.
Morishita Y, Tanai T, Hirano Y (2010). A new approach for assessing kinematics of torso twist in
baseball batting: a preliminary report. XXVIII ISBS processing, 517-518.
Nicholls RL, Elliott BC, Miller K, Koh M (2003) Bat kinematics in baseball: implications for ball
exit velocity and player safety. Journal of Applied Biomechanics, 19, 283-294.
Tabuchi N, Matsuo T, Hashizume K (2007) Bat speed, trajectory, and timing for collegiate baseball
batters hitting a stationary ball. Sports Biomechanics, 6(1), 17-30.
Tago T, Ae M, Tsuchioka D, Ishii N, Wada T (2010). Adjustment of the lower limb motion at
different impact heights in baseball batting. XXVIII ISBS proceeding, 686-689.
Potter DL, Johnson LV. Softball, steps to success. 3rdedition, Human kinetics, Champaign, IL, USA,
pp85-107, 2007.
Putman CA (1993) Sequential motions of body segments in throwing and striking skills:
Descriptions and explanations. Journal of Biomechanics, 26(suppl 1), 125-135.
Welch CM, Banks SA, Cook FF, Draovitch PD (1995). Hitting a baseball: a biomechanical
1
國科會補助專題研究計畫項下出席國際學術會議心得報告
日期：100 年 7 月 28 日
一、參加會議經過
國際運動生物力學年會暨學術研討會(International Society of Biomechanics in Sports, ISBS)，每一年都由世界各地會員國來主辦，ISBS 舉辦至今年 2011 年已經為第 29 屆了，真是相當具有代表性與歷史性的國際生物力學研討會。今年由歐洲最西方的國家-葡萄牙波多市的波多大學(University of Porto) 舉辦，會議日期為 2011 年 6 月 27 日至 7 月 1 日。 圖一：2011 年國際運動生物力學研討會標記(左)與波多大學校徽(右)。 由於臺灣並無直航飛機可以抵達葡萄牙波多，需要由其他國家來轉機，因此我們 須轉機才能抵達。首先由高雄小港機場出發飛抵香港，再轉飛到達德國法蘭克福機場， 入境歐洲之後，再繼續飛到葡萄牙波多，這超過 24 小時的長途旅程，著實令人覺得興奮
計畫編號
NSC 98－ 2410 － H －028 －003 －MY2
計畫名稱
壘球推擊技巧之生物力學分析
出國人員
姓名
張怡雯
服務機構
及職稱
國立臺灣體育學院
運動健康科學學系 副教授
會議時間
2011 年 06 月 27 日至2011 年 07 月 01 日會議地點
葡萄牙 波多 Porto, Portugal會議名稱
2011年第二十九屆國際運動生物力學研討會
29th Conference of the International Society of Biomechanics in Sports
發表論文
題目
Comparison Of Torso Twist Between Slap Hit And Ordinary Hit In Softball Batting
2 但又有些疲累。到達波多的國際機場時，已是當地時間半夜 12 點多，天色黑暗，路上荒 涼，最後我們搭乘計程車去旅館。 圖二：波多市的街景，紅磚瓦屋頂為其特色，古色古香，和臺灣的透天厝有異曲同工之妙 隔天早上起來，在旅館附近一看，發現葡萄牙果然到處是古蹟，真是一個相當漂 亮的城市，也是一個需要用心體會的歷史古都。下午我們便搭乘大會接駁車到達會場－ 波多大學的體育運動中心辦理報到，領取資料後便參加了下午的表面肌電圖工作坊 (Surface EMG workshop)，由 Delsys 講師主講，開始了一連五天研討會的序幕。晚上有開 幕儀式和酒會，並有波多大學學生表演啦啦隊，相當精采，贏得大家熱烈的掌聲。 圖三：波多大學的學生表演啦啦隊，青春洋溢。 會議的第二天到第五天的早上 8 點半，大會都有接駁車將與會學者由旅館戴到會 場，相當方便。會議議程的安排，每天早上都有一場專題演講 (Keynote speaking)，皆是 邀請世界級的運動生物力學大師來演講，相當精彩，接下來為口頭發表 (Oral presentation) 與海報發表 (Poster presentation)，參與學者都仔細聆聽，並有精闢的提問，真是令人收穫 良多。中午大會並有提供午餐，皆為葡萄牙當地的傳統美食，雖然口味和臺灣食物不同， 但也相當可口，尤其葡萄牙緊鄰大西洋，海鮮漁獲量相當豐富，品嘗當季的葡式海鮮風 味，非常新鮮。
3 圖四：參加大地遊戲之分組競賽，中間為我們這組的小隊輔。 在會議第三天的下午為戶外行程 (Social tour)，大會安排了大地遊戲，將參加學者 分組，一組 10 人左右，在波多市中心的風景名勝景點，以及許多的世界遺址 (World heritage)，讓大家回答週邊景點與古蹟的歷史問題，由於歷史文化內容深入，對於沒有深 厚歐洲歷史背景的我們，要正確回答問題，還真的有一些吃力。中間並穿插了到餐廳品 酒，品嚐歐洲頗富盛名的波多酒 (Porto wine)，並同時享用牛奶起司與羊奶起司。接著大 會帶領大家參觀了知名多羅河畔 (river Douro) 歷史悠久的 Ferreira 製酒廠，引導人員細 細解說，瞭解製酒過程的每一道繁複手續，也瞭解每一年氣溫雨量的不同，都會影響到 葡萄結果的品質，所以只有特定年分的葡萄可以拿來製酒，也同時學到了一些葡萄製酒 的知識。 圖五：來自臺灣的學者們，於波多市多羅河畔酒廠品酒時合影。 會議的最後一天的晚上，照例有閉幕晚宴(Closing banquet)，這次是在一個古色古 香的古蹟城堡中舉行，相當華麗璀燦。首先安排一段交響樂的演奏，接著入席，上菜時， 配合前菜、沙拉、主餐、甜點，服務人員會適時變化不同的紅酒或白酒來作配合，果然 是有歷史悠久品酒文化的波多城。現場同時有許多葡萄牙歌手的專業演唱表演，聲音非 常優美動聽，最後當然是各項口頭報告及海報發表優等獎項的頒發與辛苦的與會工作人 員的致謝，得獎者莫不喜悅不已。等到晚宴結束，大家相約明年澳洲墨爾本的 ISBS 2012 再見。
4 圖六：舉辦閉幕晚宴的古堡，中間為交響樂的精彩表演。
二、與會心得
此次參與會議的專家學者，來自世界各地，例如：地主國葡萄牙、英國、巴西、美 國、日本、西班牙等，大會將投稿論文第一作者的國家數量作排序，臺灣排名第七，在 整個排序上，算是相當前面的，也表示在臺灣的運動生物力學正蓬勃發展，希望能對於 競技運動與休閒運動上，能有整體正面的影響，進而提高選手的運動表現。 圖七：此次會議所發表論文的第一作者國籍統計。 此次會議主題包羅萬象，舉凡世界性的運動項目，皆有不同國家的學者在研究，其 中，投稿論文數量最多的是游泳，其次分別為跳躍、跑步、體操、短跑等。經由聆聽不 同的場次，選擇不一樣的運動主題，可以對於不同的運動型式多所瞭解。5 圖八：此次會議所發表論文的專項運動種類統計。 在這些不同的運動項目之中，我最感到有興趣的項目為跆拳道生物力學研究。由於 跆拳道為我國在亞奧運中的重點奪牌項目，亦為臺灣年輕學童參與的運動中，經常學習 的運動項目之一，在許多地方也都有跆拳道道館的設置，是一項相當普及的運動種類。 希望經由運動生物力學的量化分析，可以更精進跆拳道選手的表現，使跆拳道專項技能 能更充分發揮，最終以達到更優異的比賽成績為目的。以下為二篇跆拳道的生物力學論 文的發表結果：
Kinematical Analysis of Five Different Kicks in Taekwondo 五種不同跆拳道踢擊的運動學分析
準確的時間與快速的動作是決定跆拳道比賽成功的重要因子，因此，本研究目的為確 認哪些跆拳道的足部技巧可以在比賽中獲得最可能的成功，經由比較旋踢(round kick)、前下 踢(front leg axe kick)、下壓(clench axe kick)、旋後跳踢(jump spin back kick)和旋後勾踢(jump hook back kick)五種在跆拳道裡最常用的踢擊技巧，分析反應時間、動作時間和總反應時間， 共有八位甲組專項跆拳道選手參與此研究，利用三台 Casio HD 攝影機以 300 Hz 頻率去記錄 運動學參數，並使用頭部和頸部模型作為目標。單因子變異數分析的統計結果顯示，雖然在 反應時間並無差異，但在動作時間和總反應時間上，不同的技巧確實有顯著的不同(P<0.01)。 由此可知，在快速的比賽節奏下，應選擇動作時間最短暫迅速的踢擊技巧，才能有較佳的致 勝機會。
Mechanical Analysis of the Roundhouse Kick According to the Stance Position. A Pilot Study. 不同站立位置的旋踢之力學分析 –前測研究
跆拳道的踢擊表現受到站立位置的影響，本研究目的為分析在三種不同站立位置(0 , 45o, 90o) 下，旋踢的力學參數。共有兩位甲組跆拳道選手參與此研究，藉由兩塊測力板和八
6 台 3D 動作分析系統攝影機來測量力學參數，資料由 Visual 3D 軟體進行分析。選手在 0 與 45o位置的踢擊動作時間與總反應時間比 90o位置來的快速 (P<0.05)，而地面反作用力亦可應 用於預測動作表現的變異，因此，對於選手而言，選擇在 0 與 45o的位置比在 90o位置更容 易有較快速的總反應時間，因而能產生較優異的表現。
三、建議
在聆聽了多場的來自世界各地學者所發表的跆拳道運動生物力學的報告後，深深覺得 獲益匪淺，如何經由分析各項跆拳道的變因，找出最有利的致勝關鍵，並與教練、選手搭配 合作，統整各個影響因子，並實際應用於訓練與比賽場上，這還是目前有待大家思考與努力 的方向，也希望經由科學性的研究量化，可以把臺灣的運動水準再上一層樓，達到世界性的 頂尖層級，這也是作運動生物力學研究的最終目標。 圖九：此次會議所發表論文海報的合影。 在 2008 年曾參加過韓國首爾大學舉辦的 ISBS，及 2010 年於美國北密西根大學所舉 辦的 ISBS，此次已經是第三次參加國際運動生物力學研討會。雖然都是同一個會議，但 每一個地區或國家都有不同的文化特色，除了在會議中，運動生物力學的學術參與及討 論是一樣的熱烈之外，經由不一樣的歷史語言的洗禮，還能深刻瞭解與尊重不同文化的 特殊性。此次在歐洲歷史悠久的葡萄牙波多待了一週，發現他既有現代的文明，高水準 的人民，高科技的大眾運輸系統，但隨處閒逛，市中心也好，郊區也好，卻發現處處是 古蹟，也都保持的很完整，標記的非常清楚，古今交錯，但卻一點也不衝突。 圖十：小巷中斑駁的拱門與石牆，訴說著古老歲月的痕跡。7 臺灣的運動生物力學學會將在 2013 年於台北舉辦第 31 屆的 ISBS，到時應該會有來 自世界各地的學者專家與研究人員參加，除了邀請重量級的大師專題演講，安排各場次 的口頭發表及海報發表外，介紹臺灣文化與歷史背景給各個國家的訪客知道，也是我們 的使命之一，經由相關的活動安排導覽，希望到時可以讓大家認識臺灣、瞭解臺灣！
四、攜回資料名稱及內容
本次會議帶回的書面資料包括以下三大本：1. Programma and Abstracts Book：包含會議資訊的介紹、議程和各學者所發表的論 文摘要。
2. Biomechanics in Sports 29：包含各國學者在 2011 年 ISBS 所發表的論文內容，包含 海報及口頭原創性論文的發表，都被收錄在葡萄牙體育學會當地所出版的期刊之中 (葡萄牙運動科學期刊)Portuguese Journal of Sport Sciences, 11 (Suppl. 2), 2011。 3. Applied Biomechanics in Sports：2011 年 ISBS 研討會所邀請的專家學者主題演講內
容，則收錄於此。
五、附錄
附錄一：大會議程 附錄二：參加研討會證明 附錄三：研討會論文封面 附錄四：發表之論文摘要 附錄五：發表之海報8 附錄一：大會議程
9 附錄二：參加研討會證明
10 附錄三：研討會論文封面
11 附錄四：發表之摘要
14 附錄五：發表之海報
國科會補助計畫衍生研發成果推廣資料表
日期:2011/10/26國科會補助計畫
計畫名稱: 壘球推擊技巧之生物力學分析 計畫主持人: 張怡雯 計畫編號: 98-2410-H-028-003-MY2 學門領域: 運動生物力學無研發成果推廣資料
98 年度專題研究計畫研究成果彙整表
計畫主持人：張怡雯 計畫編號：98-2410-H-028-003-MY2 計畫名稱：壘球推擊技巧之生物力學分析 量化 成果項目 實際已達成 數（被接受 或已發表） 預期總達成 數(含實際已 達成數) 本計畫實 際貢獻百 分比 單位 備 註 （ 質 化 說 明：如 數 個 計 畫 共 同 成 果、成 果 列 為 該 期 刊 之 封 面 故 事 ... 等） 期刊論文 0 0 100% 研究報告/技術報告 0 0 100% 研討會論文 0 0 100% 篇 論文著作 專書 0 0 100% 申請中件數 0 0 100% 專利 已獲得件數 0 0 100% 件 件數 0 0 100% 件 技術移轉 權利金 0 0 100% 千元 碩士生 0 0 100% 博士生 0 0 100% 博士後研究員 0 0 100% 國內 參與計畫人力 （本國籍） 專任助理 1 1 100% 人次 期刊論文 0 2 100% 研究報告/技術報告 0 0 100% 研討會論文 3 3 100% 篇 論文著作 專書 0 0 100% 章/本 申請中件數 0 0 100% 專利 已獲得件數 0 0 100% 件 件數 0 0 100% 件 技術移轉 權利金 0 0 100% 千元 碩士生 0 0 100% 博士生 0 0 100% 博士後研究員 0 0 100% 國外 參與計畫人力 （外國籍） 專任助理 0 0 100% 人次其他成果
