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1.
The speed at which a player can swing a bat is central to the games of baseball and softball, determining, to a large extent,
the hit speed of the ball. Experimental and analytical studies of bat swing speed were conducted with particular emphasis
on the influence of bat moment of inertia on swing speed. Two distinct sets of experiments measured the swing speed of colege
baseball and fast-pitch softball players using weighted rods and modified bats. The swing targets included flexible targets,
balls on a tee and machine pitched balls. Internal mass alterations provided a range of inertial properties. The average measured
speeds, from 22 to 31 m s−1, are consistent with previous studies. Bat speed approximately correlates with the moment of inertia of the bat about a vertical
axis of rotation through the batter's body, the speed generally decreasing as this moment of inertia increases. The analytical
model assumes pure rotation of the batter/bat system about a vertical axis through the batter's body. Aerodynamic drag of
the batter's arms and the bat is included in the model. The independent variable is bat moment of inertia about the rotation
axis. There is reasonable agreement between the model and the measured speeds. Detailed differences between the two suggest
the importance of additional degrees of freedom in determining swing speed. 相似文献
2.
Walter A. Laughlin Kyle T. Aune Alek Z. Diffendaffer 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(1):36-47
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. 相似文献
3.
4.
A comparative study of baseball bat performance 总被引：2，自引：2，他引：0
Alan M. Nathan Joseph J. Crisco R. M. Greenwald D. A. Russell Lloyd V. Smith 《Sports Engineering》2011,13(4):153-162
The results of a comparative study of five aluminum and one wood baseball bats are presented. The study includes an analysis
of field data, high-speed laboratory testing, and modal analysis. It is found that field performance is strongly correlated
with the ball–bat coefficient of restitution (BBCOR) and only weakly correlated with other parameters of the bat, suggesting
that the BBCOR is the primary feature of a bat that determines its field performance. It is further found that the instantaneous
rotation axis of the bat at the moment of impact is very close to the knob of the bat and that the rotational velocity varies
inversely with the moment of inertia of the bat about the knob. A swing speed formula is derived from the field data and the
limits of its validity are discussed. The field and laboratory measurements of the collision efficiency are generally in good
agreement, as expected on theoretical grounds. Finally, the BBCOR is strongly correlated with the frequency of the lowest
hoop mode of the hollow bats, as predicted by models of the trampoline effect. 相似文献
5.
Rob Gray 《Research quarterly for exercise and sport》2013,84(3):491-501
Bat/ball contact produces visual (the ball leaving the bat), auditory ( the “crack” of the bat), and tactile (bat vibration) feedback about the success of the swing. We used a batting simulation to investigate how college baseball players use visual, tactile, and auditory feedback. In Experiment 1, swing accuracy (i.e., the lateral separation between the point of contact and “sweet spot”) was compared for no feedback (N), visual alone, auditory alone, and tactile alone. Swings were more accurate for all single-modality combinations as compared to no feedback, and visual produced the greatest accuracy. In Experiment 2, the congruency between visual, tactile, and auditory was varied so that in some trials, the different modalities indicated that the simulated ball contacted the bat at different points. Results indicated that batters combined information but gave more weight to visual. Batting training manuals, which typically only discuss visual cues, should emphasize the importance of auditory and tactile feedback in baseball batting. 相似文献
6.
Effects of swing-weight on swing speed and racket power 总被引：1，自引：0，他引：1
Measurements are presented of the speed at which six different rods could be swung by four male students. Three of the rods had the same mass but their swing-weight (i.e. moment of inertia) differed by large factors. The other three rods had the same swing-weight but different masses. Our primary objective was to quantify the effects of mass and swing-weight on swing speed. The result has a direct bearing on whether baseball, tennis, cricket and golf participants should choose a heavy or light implement to impart maximum speed to a ball. When swinging with maximum effort, swing speed (V) was found to decrease as swing-weight (Io) increased, according to the relation V = C/Ion, where C is a different constant for each participant and n = 0.27 when Io > 0.03 kg x m2. Remarkably similar results were obtained previously with softball bats (where n = 0.25) and golf clubs (where n = 0.26). Swing speed remained approximately constant as swing mass increased (when keeping swing-weight fixed). The implications for racket power are discussed. 相似文献
7.
Batter swing speed is an important parameter in understanding the performance of baseball and softball players. A number of swing speed sensors have recently been introduced and are commercially available. The aim of this study was to compare three wireless swing sensors with high speed video. Swing speed from high speed video was measured by differentiating the position coordinates of tracking markers on the bat barrel. On average, the wireless bat swing sensors reported speeds 8% slower than that found from video tracking. The agreement was better at low swing speeds, suggesting that the current generation of wireless sensors is best suited for developing players. Spatial measures, such as swing angle, were not in good agreement with video tracking. 相似文献
8.
Field and laboratory measurements of softball player swing speed and bat performance 总被引：1，自引：1，他引：0
The swing speed of the bat is one of the most important factors affecting the hit-ball speed. Most field studies tend to focus on measuring ball speed, which is easier to measure and quantify than bat speed. For this reason, relatively little data exist describing bat motion in field conditions. The following describes a relatively large swing speed field study involving bats of the same model with nearly constant weight and varying inertia. The study was conducted using right-handed batters on a regulation outdoor field with a live pitcher. Swing speed was measured by tracking markers on the bat with two high-speed video cameras so that the bat markers could be traced in three-dimensional space. The ball motion was tracked using the same high-speed video cameras and a three-dimensional Doppler radar system. Bat swing speed was observed to be proportional to the batter skill level and the normalised swing speed increased with decreasing bat inertia. The bat centre of rotation during impact was close to the knob of the bat. The bats were tested under controlled laboratory conditions using a standardised performance test. The field and laboratory results showed good agreement including the hit-ball speed and the subtle effect of bat inertia on the maximum performance location. The vibrational response of the bats was considered using modal analysis. The maximum performance location was correlated with the node of the first vibrational mode. 相似文献
9.
Reyes GF Dickin DC Crusat NJ Dolny DG 《Sports biomechanics / International Society of Biomechanics in Sports》2011,10(4):280-293
The purpose of this study was to evaluate the effects of whole-body vibration (WBV) on the muscle recruitment of selected upper and lower body muscles during the baseball swing. Participants were recreationally trained males (n = 16, 22 +/- 2 years, 181.4 +/- 7.4 cm, 84.7 +/- 9.0 kg), with previous baseball experience. Subjects participated in three randomized sessions on separate days, consisting of three sets of five swings offa hitting tee. Exercises (upper and lower body dynamic and static movements) with or without WBVexposure were performed between swing sets. During each swing, the gastrocnemius, biceps femoris, gluteus maximus, pectoralis major, latissimus dorsi, and triceps brachii were evaluated for electromyographic (EMG) activity. EMG values were normalized to EMG measured during maximal voluntary isometric contraction. Statistical analysis revealed no significant differences in EMG activity across the three treatments. In addition, the results displayed a specific muscle recruitment order during the swing, starting with the lower body followed by the upper body muscles. This study was the first to report the recruitment order during the baseball swing. Although acute exposure to WBV did not significantly alter the muscle recruitment, these results may prove useful for practitioners looking to enhance baseball swing performance. 相似文献
10.
Hitting a major league fastball, with approximately half a second to react, poses one of the greatest challenges in sports.
The ability to hit the ball derives from the dynamics of the bat swing which can be measured using video motion capture. However,
doing so necessitates swinging the bat within the confines of a motion capture laboratory, often with considerable time and
expense. This paper introduces an inexpensive and highly portable measurement method for use right on the field of play to
support player training, coaching, rehabilitation, and player-bat fitting. The method employs a highly miniaturized, wireless
MEMS inertial measurement unit (IMU) affixed to the knob of the bat. The IMU incorporates three-axis sensing of bat acceleration
and angular velocity with a low-power RF transceiver to transmit this data to a host computer. Analysis of this data yields
a near-instantaneous and highly resolved summary of three-dimensional bat dynamics. This paper describes this novel technology
for use in baseball and softball, presents example results, and reveals new features of bat motion overlooked in previous
studies. 相似文献
11.
Tabuchi N Matsuo T Hashizume K 《Sports biomechanics / International Society of Biomechanics in Sports》2007,6(1):17-30
The aims of this study were to examine whether batters hit stationary balls at the time of peak speed of the bat head and whether the impact occurs at the lowest point of the bat trajectory. Eight university baseball players hit three balls, each hung with a string; each ball was made of a different material and was different in weight. Bat movement was captured by four 240-Hz infrared cameras and analysed three-dimensionally. Time for peak speed of the bat head varied according to the conditions. When stationary balls of standard weight were used, the bat head was at maximum speed at impact with the ball; then, it decelerated drastically owing to the impact. In contrast, maximum speed was obtained after impact when lightweight stationary balls were used. The time-speed profile of the bat head before impact in the lightweight ball condition was identical with that in the standard weight ball condition. Regardless of conditions, the timing of the lowest point of the bat head was nearly identical for each batter and most participants hit the stationary balls at about the lowest point of the bat trajectory. 相似文献
12.
Donald E. Race 《Research quarterly for exercise and sport》2013,84(3):394-404
Abstract A controlled, cinematographic study was made of 17 proficient, professional hitters of the Eastern League hitting a baseball effectively, in order to make a qualitative and quantitative analysis of the mechanics of hitting. Angular measurements of the forward-swing bat delineated a sharply increasing rate of velocity as the bat approached the baseball. Responsibility for the generation of the force imparted to the bat was made manifest by the far greater velocity of the hands-and-wrists over the hips, and, similarly, of the hips over the striding foot. Additional analyses were made of the efforts to maintain bodily balance, the judgment time of each hitter, the changing levels of the head, the preparatory movements of the stance, and the extent of arm movement before the follow-through. 相似文献
13.
NORIYUKI TABUCHI TOMOYUKI MATSUO KEN HASHIZUME 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(1):17-30
The aims of this study were to examine whether batters hit stationary balls at the time of peak speed of the bat head and whether the impact occurs at the lowest point of the bat trajectory. Eight university baseball players hit three balls, each hung with a string; each ball was made of a different material and was different in weight. Bat movement was captured by four 240-Hz infrared cameras and analysed three-dimensionally. Time for peak speed of the bat head varied according to the conditions. When stationary balls of standard weight were used, the bat head was at maximum speed at impact with the ball; then, it decelerated drastically owing to the impact. In contrast, maximum speed was obtained after impact when lightweight stationary balls were used. The time–speed profile of the bat head before impact in the lightweight ball condition was identical with that in the standard weight ball condition. Regardless of conditions, the timing of the lowest point of the bat head was nearly identical for each batter and most participants hit the stationary balls at about the lowest point of the bat trajectory 相似文献
14.
This study addressed the question, what should baseball players focus their attention on while batting? Less-skilled and highly skilled (college) baseball players participated in four dual-task conditions in a baseball batting simulation: two that directed attention to skill execution (skill/internal [movement of the hands] and skill/external [movement of the bat]) and two that directed attention to the environment (environmental/irrelevant [auditory tones] and environmental/external [the ball leaving the bat]). Batting performance for highly skilled players was best in the environmental/external condition and worst in the skill/internal condition. Performance of less-skilled batters was significantly better in the two skill conditions than in either of the two environmental conditions. We conclude that the optimal focus of attention for highly skilled batters is one that does not disrupt proceduralized knowledge and permits attention to the perceptual effect of the action, whereas the optimal focus of attention for less-skilled batters is one that allows attention to the step-by-step execution of the swing. 相似文献
15.
Brittany Dowling Glenn S. Fleisig 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(3):255-269
Determining and understanding baseball batting mechanics at various competition levels may help players and coaches identify key kinematics crucial to being a successful hitter. The purpose of this study was to compare batting kinematics across competition levels. Kinematic and temporal data were analysed for 170 male batters (youth n = 33; high school n = 69; college n = 22; professional n = 46) using 3D motion capture (480 Hz). The results showed differences in angular positions between competition levels during the five phases of the swing, with the greatest differences seen between the youth and professional batters. At the instant of ball contact, professional batters held the bat farther away from their body, with greater back shoulder abduction (35°) and less back elbow flexion (78°) compared to youth (27° and 89°, respectively). These differences were associated with greater back elbow extension velocity for professionals (1539°/s) compared to youth (1174°/s). Additionally, higher level batters had higher bat angular and linear velocities compared to the youth batters. As batters progress through their career, they should focus on their back arm by keeping their elbow up and their arm extended in front of them. 相似文献
16.
Abstract Measurements are presented of the speed at which six different rods could be swung by four male students. Three of the rods had the same mass but their swing-weight (i.e. moment of inertia) differed by large factors. The other three rods had the same swing-weight but different masses. Our primary objective was to quantify the effects of mass and swing-weight on swing speed. The result has a direct bearing on whether baseball, tennis, cricket and golf participants should choose a heavy or light implement to impart maximum speed to a ball. When swinging with maximum effort, swing speed (V) was found to decrease as swing-weight (I o) increased, according to the relation V?=?C/I o n , where C is a different constant for each participant and n?=?0.27 when I o >?0.03 kg?·?m2. Remarkably similar results were obtained previously with softball bats (where n?=?0.25) and golf clubs (where n?=?0.26). Swing speed remained approximately constant as swing mass increased (when keeping swing-weight fixed). The implications for racket power are discussed. 相似文献
17.
A cinematographic analysis of the drive off the front foot (D) and the forward defensive stroke (FD) was undertaken to establish the kinematic and kinetic factors involved in playing these strokes against medium-fast bowling. Fourteen provincial cricket batsmen were filmed at 100 Hz while batting on a turf pitch with a specially instrumented bat. Results for the drive off the front foot revealed that the movement and stroke pattern were generally supportive of the coaching literature, with the forward defensive stroke forming the basis of the drive. Certain mechanical differences, although non-significant, were evident to facilitate the attacking nature of the front foot drive and included a higher backlift (FD = 0.65 m; D = 0.74 m), later commencement of the stride (FD = 0.64 s pre-impact; D = 0.58 s pre-impact) and downswing of the bat (FD = 0.38 s pre-impact; D = 0.36 s pre-impact), a shorter front foot stride (FD = 0.72 m; D = 0.68 m) with the front foot placement taking place later (FD = 0.14 s pre-impact; D = 0.06 s pre-impact), and the back foot dragging further forward at impact (FD = 0.05 m; D = 0.10 m). The front upper limb moved as a multi-segmental series of levers, which resulted in the drive showing significantly greater (P< 0.05) peak bat horizontal velocity at 0.02 s pre-impact (FD = 3.53 +/- 3.44 m s(-1); D = 11.8 +/- 4.61 m x s(-1)) and 0.02 s post-impact (FD = 2.73 +/- 2.88 m x s(-1); D = 11.3 +/- 4.21 m x s(-1)). The drive showed a significantly greater (P < 0.05) bat-ball closing horizontal velocity (FD = 24.2 +/- 4.65 m x s(-1); D = 32.3 +/- 5.06 m x s(-1)) and post-impact ball horizontal velocity (FD = 6.85 +/- 5.12 m x s(-1); D = 19.5 +/- 2.13 m x s(-1)) than for the forward defensive stroke. The point of bat-ball contact showed nonsignificant differences, but occurred further behind the front ankle (FD = 0.09 +/- 0.17 m; D = 0.20 +/- 0.13 m), with the bat more vertical at impact (FD = 62.6 +/- 6.53 degrees ; D = 77.8 +/- 7.05 degrees). Significant differences (P< 0.01) occurred between the grip forces of the top and bottom hands for the two strokes, with the principal kinetic finding that the top hand plays the dominant role during the execution of the drive with the bottom hand reinforcing it at impact. Similar grip force patterns for the two strokes occurred during the initial part of the stroke, with the drive recording significantly greater (P < 0.05) forces at 0.02 s pre-impact (top hand: FD = 129 +/- 41.6 N; D = 199 +/- 40.9 N; bottom hand: FD = 52.2 +/- 16.9 N; D = 91.8 +/- 41.1 N), at impact (top hand: FD = 124 +/- 29.3 N; D = 158 +/- 56.2 N; bottom hand: FD = 67.1 +/- 21.5 N; D = 86.2 +/- 58.2 N) and 0.02 s post-impact (top hand: FD = 111 +/- 22.2 N; D = 126 +/- 28.5 N; bottom hand: FD = 65.5 +/- 26.9 N; D = 82.4 +/- 28.6 N). 相似文献
18.
《European Journal of Sport Science》2013,13(3):155-162
Abstract Over the past few years, there has been a significant increase in the performance of softball bats from the Olympics down to the recreational level. It is theorized that the introduction of composite-based material bats has been the largest contributor to the increase in batted-ball performance, which directly corresponds to a decrease in available pitcher reaction time that can lead to an increase in injury potential. To test this theory, a controlled field-test study comparing all of the different bat model types currently available was conducted. The performance of ten bat model types; two composite-based, two titanium-based, two aluminum-based multi-wall, two aluminum-based single-wall and two wood-based bats were measured using 1686 N/0.64 cm (379 lbs/0.25”) compression softballs in order to calculate available pitcher reaction times when using a specific bat model type. Over 1000 Batted-ball velocity measurements were analyzed using two calibrated radar devices and five experienced test subjects. The results of this study indicate that when titanium-based or composite-based softball bat performance results are compared to published safety studies in the sports of softball and baseball, available pitcher reaction times are unsafe, which can lead to a higher injury risk potential. The significance of this research is to provide experimental field-test data on the possible safety risks to pitchers that can be used to reduce the injury potential and promote safety awareness in the sport of softball. 相似文献
19.
The sweet spot of a cricket bat for low speed impacts 总被引：2，自引：1，他引：1
Rob Bower 《Sports Engineering》2012,15(2):53-60
The impact location of a cricket ball on a cricket bat has a large influence on the resulting rebound velocity of the ball. To measure this, a cricket bat was swung in a pendulum motion towards a cricket ball suspended in space. The position of the ball was modified so that it impacted the bat at 24 different positions on the face of the bat. This included six positions longitudinally and four positions laterally. The speed of the bat and each rebound were measured by a radar gun so that the apparent coefficient of restitution (ACOR) could be calculated. Impacts occurring centrally and 1?cm either side of the midline produced significantly higher rebound speeds and ACOR??s than impacts occurring 2 and 3cm off centre (p?<?0.01). Impacts occurring 15?C20?cm from the base of the bat produced the highest rebound speeds (p?<?0.01) and impacts occurring 20?C30?cm from the base of the bat produced the highest ACOR values. Implications for higher speed impacts and game scenarios are discussed. 相似文献
20.
Ben L. Langdown Jack E.T. Wells Sean Graham Matt W. Bridge 《Journal of sports sciences》2019,37(6):656-664
Previous research has highlighted the positive effect that different warm-up protocols have on golf performance (e.g. Sorbie et al., 2016; Tilley & Macfarlane, 2012) with the design of warm-ups and programmes targeting and improving golf performance through the activation and development of specific muscle groups. This study aimed to examine the acute effects of two warm-up protocols on golf drive performance in comparison to a control condition. Using a randomised counterbalanced design over three testing sessions, twenty-three highly skilled golfers completed the control, dynamic and resistance-band warm-up conditions. Following each condition, a GC2 launch monitor was used to record ball velocity and other launch parameters of ten shots hit with the participants’ own driver. A repeated-measures ANOVA found significant increases in ball velocity (ηp2 = .217) between the control and both the dynamic and resistance-band warm-up conditions but no difference between these latter two, and a reduction in launch angle between control and dynamic conditions. The use of either a dynamic stretching or resistance-band warm-up can have acute benefits on ball velocity but golfers should liaise with a PGA Professional golf coach to effectively integrate this into their golf driving performance. 相似文献