Batting performance of wood and metal baseball bats

INTRODUCTION/PURPOSE: Although metal baseball bats are widely believed to outperform wood bats, there are few scientific studies which support this. In a batting cage study, Greenwald et al. found that baseballs hit with a metal bat traveled faster than those hit with a wood bat, but the factors responsible for this difference in bat performance remain unidentified. The purpose of this study was to determine the effects of swing speed, impact location, and elastic properties of the bat on batted ball speeds. METHODS: The pitched ball, batted ball, and swings of two wood and five metal baseball bats by 19 different players were tracked in three dimensions at 500 Hz using a passive infrared motion analysis system. RESULTS: Increases in the batted ball speeds of metal bats over those of wood bats resulted from faster swing speeds and higher elastic performance with an apparent increase in the ball-bat coefficient of restitution. The contribution of these variables to batted ball speed differed with metal bat model. The "sweet spot" associated with maximum batted ball speeds was located approximately the same distance from the tip of wood bats as it was from metal bats. CONCLUSIONS: The variables that correlated with differences between metal and wood bat performance, and most notably differences in the percentage of faster batted balls, were identified using a novel kinematic analysis of the ball and bat. These variables and their correlation with bat performance should be applicable to other players and bats, although more skilled players and higher performing bats would likely result in even faster batted ball speeds.     

Impact injuries in baseball : prevalence, aetiology and the role of equipment performance

Baseball has one of the highest impact injury rates of all sports. These injuries are primarily attributed to impact by a ball after it has been hit, pitched or thrown. This paper will review the incidence and causal factors for impact injuries in baseball. Attention is given to the design and material properties of bats, in light of evidence suggesting balls hit into the infield from metal bats can reach velocities potentially lethal to defensive players. The distribution of bat mass along the long axis of the implement appears a major factor in the greater performance potential of metal bats over wooden bats of equal length and mass. The dynamic behaviour of baseballs has also been implicated in the severity of head and chest injuries experienced by players. Balls of greatly reduced stiffness have been introduced for junior play, but debate still remains over their performance and impact characteristics. The behaviour of the ball during high-speed impact with the bat has been the subject of relatively limited research, and the effect of manipulating baseball material properties to decrease batted-ball velocity is unclear. The value of batting helmets is evident in the observed reduction of head injuries in baseball, but the use of protective vests to decrease the incidence and severity of cardio-thoracic trauma appears to be contraindicated.     

Influence of ball velocity,attention, and age on response time for a simulated catch

PURPOSE: The ability of a baseball infielder to respond to a batted ball may provide the best defense for avoiding injury. This study investigated the response times of young athletes performing a simulated baseball-fielding task to estimate the maximum velocity with which a baseball can leave the bat and allow a player, standing 13.7 m away, to safely respond to the approaching ball. METHODS: Fifty boys and 50 girls between the ages of 8 and 16 yr participated. Baseballs were projected at the subjects who were standing in a standardized position behind a safety net. Two components of response time, reaction time and movement time, were determined using a motion capture system. The influences of baseball velocity (26.8 and 33.5 m.s(-1) and level of attention (full attention and attention splitting) on response time for a simulated baseball-fielding task were characterized. Based on the response times for each age group, the maximum exit-velocity from a baseball-bat interaction that would allow a young baseball player sufficient time to safely respond to an approaching baseball was calculated. RESULTS: The results showed that subjects had sufficient time to respond to exit-velocities from 26.8 m.s-1 (8- to 9-yr-old group) to 33.5 m.s-1 (16-yr-old group). However, the accuracy of the response was negatively affected by baseball velocity. CONCLUSIONS: If the exit-velocities seen during actual competition exceed the calculated maximum exit-velocities for these age groups, then our preliminary data suggest that modifications to the game of baseball that would reduce the actual exit-velocities and serve as an effective means to reduce the potential for serious or catastrophic injury are warranted.     

Effects of bat composition, grip firmness, and impact location on postimpact ball velocity

The purpose of this investigation was to examine the effects of bat composition (aluminum and wooden), impact location [center of percussion (COP), center of gravity (COG), and end of the bat (E)], and grip firmness [tight (T) and no tension (NT)] on postimpact ball velocity. With the bats placed alternately in NT and T conditions, baseballs were delivered at a speed of 27.1 m.s-1 from a pitching machine positioned 1.5 m from the bat. High-speed photography (400 fps) was performed using a Locam camera positioned 7.54 m from and perpendicular to the principal plane of ball movement. A three-way ANCOVA revealed significant (P less than 0.01) differences in postimpact ball velocity between the three impact locations, with the COP yielding the greatest values, followed by the COG and E. Moreover, there was a significant (P less than 0.01) grip vs bat interaction. A simple-effects procedure revealed the following results: 1) the T grip produced greater (P less than 0.01) velocities than the NT grip across the aluminum (Al) bat; 2) there was no difference (P greater than 0.01) between the T and NT grips across the wooden (W) bat; 3) the W bat produced greater (P less than 0.01) velocities than the Al bat across the NT grip; and 4) there was no difference (P greater than 0.01) between the Al and W bats across the T grip.(ABSTRACT TRUNCATED AT 250 WORDS)     

A controlled study on batted ball speed and available pitcher reaction time in slowpitch softball

Objectives: To investigate safety risks in slowpitch softball by conducting laboratory and experimental studies on the performance of high tech softball bats with polyurethane softballs. To compare the results with the recommended safety standards.

Methods: ASTM standard compression testing of seven softball models was conducted. Using these seven softball models, bat/ball impact testing was performed using seven adult male softball players and six high tech softball bat models to determine mean batted ball speeds. Over 500 bat/ball impact measurements were recorded and analysed. Available pitcher reaction time was calculated from the mean batted ball speed measurements.

Results: According to the United States Specialty Sports Association and the Amateur Softball Association, the maximum initial batted ball speed should be 137.2 km/h, which corresponds to a minimum pitcher reaction time of 0.420 second. These experiments produced mean batted ball speeds of 134.0–159.7 km/h, which correspond to available pitcher reaction times of 0.409–0.361 second.

Conclusion: The use of high tech softball bats with polyurethane softballs can result in batted ball speeds that exceed the recommended safety limits, which correspond to decreased available pitcher reaction times.

     

Effects of selected softball bat loading strategies on impact reaction impulse

Interior loading strategies to modify the location and size of the effective hitting area of aluminum softball bats were identified. The effects of these strategies on theoretically derived and empirically determined relevant mechanical parameters were compared. Loading strategies consisted of adding 315 g to the interior of three similar (790 g) aluminum softball bats: at the center of mass of the original bat (bat C); at the ends of the bat and distributed so that the center of mass was unchanged, (bat A); and at the ends of the bat and distributed so that the moment of inertia about the swing axis (I1) was the same as that of bat C (bat B). The following parameters were derived theoretically by considering the bat as a physical pendulum and empirically by observing the impact reaction impulse on the axis of suspension: moment of inertia about the suspension axis (I0); moment of inertia about the swing axis; distance from the suspension axis to the center of percussion; and the slope of the impact reaction impulse (P1) relative to the impact impulse (P) as a function of impact location. These values for each bat were compared. Both empirical and theoretically derived data indicated that: the center of percussion of bat B was farther away from the axis than bats A and C; the moment of inertia about the swing axis of bat A was much greater than that of bats B and C; and the slope of the impact reaction regression line as a function of impact location for bat B was significantly less than that of the other bats. Thus, the effective hitting area of bat B was moved toward the barrel end of the bat and enlarged without a substantial increase in the moment of inertia about the swing axis.     

A formula for comparison of selected sport ball compressibility.

The purpose of this study was to develop a formula to determine and compare the compressibility of selected sport balls. Six balls (basketball, volleyball, soccer ball, baseball, handball, golf ball) were dropped ten times from each of four different heights onto a smooth solid surface overlaid with a white sheet of typing paper, overlaid with a sheet of carbon paper. The diameter of the area of contact of each ball imprinted onto the typing paper was measured in millimetres with calipers. From the data, the distance (d) that each ball compressed for each velocity (v) was calculated. It was found that a linear relationship existed between velocity at impact and the distance for each ball studied. The compressibility coefficient (c) for each ball was calculated and a formula was developed to determine the distance each ball would compress at a given velocity. When velocity is measured in metres per second and the distance a ball compresses is measured in millimetres, the formula to determine d for selected balls, in order of compressibility is: basketball d = 3.07v, volleyball d = 2.90v, soccer ball d = 2.80v, baseball d = 0.77v, handball d = 0.53v, and golf ball d = 0.17v.     

Catastrophic injuries in high school and college baseball players

BACKGROUND: There are few epidemiologic studies of catastrophic baseball injuries. PURPOSE: To develop a profile of catastrophic injuries in baseball players and to describe relevant risk factors. STUDY DESIGN: Retrospective cohort study. METHODS: The authors reviewed 41 incidents of baseball injuries reported to the National Center for Catastrophic Sports Injury Research from 1982 until 2002. RESULTS: There were an estimated 1.95 direct catastrophic injuries per year, or 0.43 injuries per 100,000 participants. The most common mechanisms of injury were a collision of fielders (9) or of a base runner and a fielder (8), a pitcher hit by a batted ball (14), and an athlete hit by a thrown ball (4). Catastrophic injuries included 23 severe head injuries, 8 cervical injuries, 3 cases of commotio cordis, and 2 cases each of a collapsed trachea and facial fractures. Three athletes sustained a severe head injury and facial fractures. Ten of the 41 injuries were fatalities. CONCLUSIONS: Suggestions for reducing catastrophic injuries in baseball include teaching proper techniques to avoid fielding and baserunning collisions, protecting the pitcher via a combination of screens and/or helmets with faceguards, continued surveillance and modifications of the bat and ball, eliminating headfirst slides, and continued analysis of chest protectors and automatic external defibrillators for commotio cordis.     

Movement characteristics of the tennis volley.

PURPOSE: The purpose of this study was to examine selected movement characteristics of the tennis volley by evaluating temporal and ground reaction force (GRF) parameters. METHODS: Seven skilled tennis players performed volley strokes under 18 experimental conditions including variations in lateral contact location (forehand (FH) and backhand (BH)), ball contact height (high, middle, low), and ball speed (fast, medium, slow). A ball machine was modified so that the subjects could not predict the ball trajectory before it was released from the machine. The GRF and temporal parameters were determined using two force platforms and two high-speed (120 Hz) video cameras, respectively. Average and maximum values of each measured parameter were computed for different phases of the volley. RESULTS: The average reaction times (from ball release to initial racquet movement (IRM)) for FH and BH trials were 226 and 205 ms, respectively, and the difference was statistically significant. The average stroke time (from IRM to ball impact) ranged from 381 ms in fast speed trials to 803 ms in slow speed trials. A distinct racquet forward motion immediately before ball impact occurred in 75% of the trials and they were evenly distributed between FH and BH trials. An ipsilateral side step (a side step of the foot on the same side of the oncoming ball before the crossover step of the other foot) occurred more often in FH (45%) than in BH (34%) trials. CONCLUSIONS: The GRF during the stroke phase suggest that the subjects initiated lateral movement by leaning sideward when ball velocity was low and by a vigorous pushoff of the contralateral foot when ball velocity was high.     

Theoretical study of the effect of ball properties on impact force in soccer heading

PURPOSE: The objective of this study was to theoretically model, based on the Hertz contact theory, the impact force and contact time, as well as the linear and angular head accelerations during heading in children using two neck stiffness conditions (infinite and negligible stiffness). METHODS: The following mathematical model inputs were obtained: elastic modulus and mass of size three, four, and five balls at inflation pressures of 10, 12, and 14 psi, head modulus, head mass, head length, head and trunk moment of inertia, and the precontact ball velocity. The model outputs consisted of linear and angular head acceleration, impact force, contact time between the ball and head, and head impact criteria (HIC) all at the point of impact. Head mass and length were obtained as a percentage of body weight and height, respectively, based on age. RESULTS: With an increase in head mass, there is a decrease in the linear and angular head acceleration. With an increase in ball size, for the same head mass, there is an increase in the contact time between the head and the ball. Changing ball inflation pressure has little effect on the impact characteristics. Infinite neck stiffness decreased linear and angular head acceleration and HIC. CONCLUSION: Head mass and ball size have an effect on linear and angular head acceleration and contact time, respectively, whereas ball inflation pressure has a minimal effect on the impact characteristics. These results indicate that children should be restricted to using the appropriate ball for their age. Smaller head size within an age group is an underemphasized though important identifier of a player's injury risk.     

Blunt force impact to the head using a teeball bat: systematic comparison of physical and finite element modeling

Blunt head trauma secondary to violent actions with various weapons is frequently a cause of injury in forensic casework; differing striking tools have varying degrees of injury capacity. The systematic approach used to examine a 19-year-old student who was beaten with a wooden teeball bat will be described. The assailant stopped beating the student when the teeball bat broke into two pieces. The surviving victim sustained bruises and a forehead laceration. The State’s Attorney assigned a forensic expert to examine whether the forces exerted on the victim’s head (leading to the fracture of the bat) were potentially life threatening (e.g. causing cranial bone fractures). Physical modeling was conducted using a pigskin-covered polyethylene end cap cushioned by cellulose that was connected to a piezoelectric force gauge. Experiments with teeball bats weighing 295–485 g demonstrated that 12–20 kN forces were necessary to cause a comparable bat fracture. In addition to physical testing, a computer-aided simulation was conducted, utilizing a finite-element (FE) method. In the FE approach, after selecting for wood properties, a virtual bat was swung against a hemisphere comprising two layers that represented bone and soft tissue. Employing this model, a 17.6 kN force was calculated, with the highest fracture probability points resembling the fracture patterns of the physically tested bats.     

The effects of extended play on professional baseball pitchers

The purpose of this study was to investigate kinematic and kinetic changes as a result of extended play in baseball pitching. Seven major league baseball pitchers were videotaped with high-speed (120 Hz) cameras during multiple innings of the same game. For each athlete, two fastballs (one thrown during the initial inning of play and one from the final inning) were chosen for analysis. Twenty-one physical landmarks were manually digitized from the video data. Kinematic and kinetic parameters were subsequently calculated relative to four phases of the pitching motion: windup, cocking, acceleration, and follow-through. Paired t-tests revealed that seven parameters changed significantly between early and late innings. These included decreases in maximum external rotation of the shoulder, knee angle at ball release, ball velocity, maximum distraction force at both the shoulder and elbow, and horizontal adduction torque at both release and its maximum value. Ultimately, a decline in performance was evident by a 2 m/s (5 mph) drop in ball speed. It is unclear whether the kinematic and kinetic changes occurred because of fatigue or if protective mechanisms were adopted.     

Comparing performance and kinematics of throwing with a circular and whip‐like wind up by experienced handball players

The aim of this study was to compare the performance (throwing velocity of the ball) and kinematics of overarm throwing with the circular and whip‐like wind up in elite handball players. Twenty‐two elite handball players (11 men and 11 women) conducted both types of throws. The ball release velocity, maximal ball acceleration, maximal velocity of the end points of the five segments and maximal angles, angles at ball release and maximal angular velocities of the 11 joint movements and their timing during the throw were analyzed. Significantly higher ball release velocities (21.9 m/s vs 20.6 m/s) were reached together with higher maximal linear velocities of the end points of all segments and longer throwing time with the circular wind up than with the whip‐like wind up. Furthermore, it seems that the timing and amount of maximal angular pelvis rotation was the main contributor to the difference in the maximal ball release velocity between the two wind ups. The findings support the observation that overarm throwing with the circular wind up results in higher ball releases but also a longer throwing movement in comparison to whip‐like wind up throws.     

The influence of mound height on baseball movement and pitching biomechanics

ObjectivesTo determine whether mound height is associated with baseball movement (velocity, spin and break) and baseball pitching biomechanics (kinematics and kinetics).DesignControlled laboratory study.MethodsTwenty collegiate baseball pitchers threw five fastballs and five curveballs from four different mound heights (15 cm, 20 cm, 25 cm, 30 cm) in a randomized order. Ball movement was computed by a ball tracking system, while pitching biomechanics were calculated with an 11-camera optical motion capture system. Repeated measures analysis of variance was utilized to detect significant differences among the four different mound heights (p < 0.05) for the fastball and curveball pitches.ResultsThere were no significant differences observed for ball movement. There were seven significant kinematic differences for fastballs and eight kinematic differences for curveballs. Although these differences were statistically significant, the magnitudes were small, with most joint angles changing by less than 2°. There were no significant kinetic differences for curveballs, but five kinetic parameters (elbow varus torque, elbow flexion torque, elbow proximal force, shoulder internal rotation torque, and shoulder anterior force) varied with mound height for fastballs. In general, fastball kinetics were 1%–2% less from the lowered (15 cm, 20 cm) mounds than from the standard (25 cm) or raised (30 cm) mounds.ConclusionsLowering the mound may not affect a pitcher’s ball movement, but may slightly reduce shoulder and elbow kinetics, possibly reducing the risk of injury.     

Validity and reliability of a simple categorical tool for the assessment of interceptive skill

Validity and reliability of a categorical tool for assessment of quality of bat–ball contact in cricket batting was examined in a natural setting. A batsman was filmed by twin synchronised cameras from front-on and side-on while facing deliveries from a leg spin bowler. The front-on camera allowed calculation of linear displacement of the ball from the bat at a point when the ball was in contact with the bat or adjacent to the edge (determined from the second camera). A strong relationship was found between observer categorisation of bat–ball contacts (i.e., good, bad and no contacts) and displacement of the ball from the bat. In addition, ‘live’ categorisation of a sample of bat–ball contact trials by a trained assistant was found to have high intra-rater reliability when re-assessed via a video record on two later occasions, as well as high inter-rater reliability when categorisation of bat–ball contact was conducted on the same video record of trials by an elite cricket coach. The findings support the value of a simple tool for assessment of interception in cricket batting that may be adapted to examine interception in other striking sports.     

Effect of ball size on player reaction and racket acceleration during the tennis volley

The purpose of this study was to examine the effect of ball size on reaction time (from ball projection to initial racket movement), movement time (from ball projection to ball-racket impact), mean rectified acceleration and vibration frequency of the racket during the impact phase (100 ms duration after ball-racket impact) of the tennis volley. Twenty-nine beginning to intermediate level tennis players performed volleys under 18 experimental conditions including variations in lateral contact location (forehand and backhand), ball type (Penn oversize, Wilson oversize, regular size), and ball speed (fast, medium, slow). A ball machine was shielded so that the subjects could not predict the ball trajectory before it was released from the machine. Outcome measures were determined using a miniature uni-axial accelerometer and a Photogate timing device. ANOVA with repeated measures and Tukey's post hoc tests were used in statistical analyses (p < .025). The reaction times for the fast speed were significantly shorter than the corresponding times for the slow speed and the reaction times for the forehand volley were significantly shorter than that of the backhand volley. The significant interaction in movement time between ball speed and ball type indicates that the benefits of the larger ball (to slow the game down) increase as the ball speed increases. No significant effect of ball type or ball speed, or interactions were found on mean rectified acceleration and vibration frequency. These results suggest that oversized balls would not cause an increased load to the hitting arm while executing a tennis volley.     

Tennis: the effects of grip firmness on ball velocity after impact

The effects of grip firmness on the ball velocity after impact has been investigated in tennis. The average horizontal velocity of the ball prior to contact and after completion of contact was determined by a motion-picture camera. A tennis ball was fired from a machine to impact with a tennis racket, which was fixed in several different positions. No significant difference was found between the velocity of the ball after impact with a racket which was horizontally clamped and with a racket in a balanced, upright position. The velocity ratio (post-impact vs pre-impact velocity) was an inverse function of the velocity of impact.     

Biomechanics and injury risk of a headbutt

Headbutt is a relevant type of a criminal assault that can result in injuries. The aim of this study was to collect basic biomechanical data and assess the injury risk associated with a headbutt. Series of measurements were carried out with volunteers with and without relevant soccer heading experience, and the impact velocity of the striking head was measured. A soccer ball was used as a surrogate of the stationary victim’s head. Two scenarios were considered: one corresponding to the typical headbutt situation, i.e. short movement of the assailant’s head without backswing, and one representing the worst case, i.e. the most severe head impact without time or space constraints for the assailant. The results as well as epidemiological data from court cases and a large Munich’s university clinic show that a typical headbutt is not likely to lead to life-threatening injuries, but bony injuries of the face can easily occur. Under certain circumstances (support of the victim’s head, secondary impact on the ground etc.), severe injuries with potentially lethal outcomes are possible. A thorough analysis of each case is thus an imperative. The (soccer) heading experience does not influence the velocity of the headbutt.     

The influence of baseball pitching distance on pitching biomechanics,pitch velocity,and ball movement

ObjectivesTo determine whether increasing pitching distance for adult baseball pitchers would affect their upper extremity kinetics, full-body kinematics, and pitched ball kinematics (ball velocity, duration of ball flight, vertical and horizontal break, strike percentage).DesignControlled laboratory study.MethodsTwenty-six collegiate baseball pitchers threw sets of five full-effort fastballs from three different pitching distances (18.44 m, 19.05 m, 19.41 m) in a randomized order. Ball velocity, horizontal and vertical break, duration of ball flight, and strike percentage were computed by a ball tracking system, while pitching kinetics and kinematics were calculated with a 12-camera optical motion capture system. Repeated measures analysis of variance was utilized to detect significant differences among the three different pitching distances (p < 0.05).ResultsNo significant differences in pitching kinetics and kinematics were observed among the varying pitching distances. Ball velocity and strike percentage were also not significantly different among the pitching distances, however, the duration of ball flight and horizontal and vertical break significantly increased with pitching distance.ConclusionsIncreasing pitching distance may not alter upper extremity kinetics, full-body kinematics, ball velocity or strike percentage in adult pitchers. However, as pitching distance increases the duration of ball flight and amount of horizontal and vertical break also increase. Increased ball flight duration could be an advantage for the hitter while increased ball break could help the pitcher. In conclusion, it is unlikely that moving the mound backwards would significantly affect pitching biomechanics and injury risk; however, the effects on pitching and hitting performance are unknown.     

Throwing effectiveness and rotational strength of the shoulder in team handball

AIM: The purpose of this study was to examine: a) the influence of simulated game activities (SGA) in throwing effectiveness and rotational strength of the shoulder; and b) the relationship between the rotational strength of the shoulder and ball velocity and accuracy in team handball. METHODS: Sixteen female handball players participated following a SGA, which included distinctive handball activities for 60 min (2 halves of 30 min). For testing ball velocity and accuracy, every 10 min, subjects performed 3 shots on the spot towards a target from 7 m distance. Shoulder isokinetic strength during internal (IR) and external rotation (ER) was evaluated in 3 angular velocities (60, 180, and 300 degrees /s) before SGA, during half-time and at the end of SGA. RESULTS: Throwing effectiveness was significantly affected by time, as aiming accuracy was gradually decreased. However, ball velocity remained stable. The correlation between ball velocity and deviation was not significant throughout the SGA. No statistically significant differences between measurements were found in maximum isokinetic torque, except from the case of ER at 180 degrees /s, where there was a significant difference between initial measurement (IM) and A and B halves. A significant relationship between isokinetic torque and ball velocity was found only for the IM for ER (180, 300 degrees /s) and IR (300 degrees /s). CONCLUSION: The main findings of this study are that, during a game simulation, time affects only aiming accuracy and not ball velocity or rotational strength of the shoulder. Moreover, peak torque of IR and ER of the shoulder is not related with ball velocity and throwing effectiveness.