Initial Ball Velocity Research Articles

Kinematic Parameters Predictive of Pitch Velocity in Youth to Professional Baseball Pitchers: A Qualitative Systematic Review.

Specific kinematic factors have been found to contribute to faster pitch speeds, with poor mechanics leading to injury. To discuss the kinematic parameters that predict faster ball velocity among baseball pitchers. Systematic review. Using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, the authors utilized the Cochrane Database of Systematic Reviews, PubMed (2008-2019), and OVID/MEDLINE (2008-2019) databases. Eligible articles included those that reported on kinematic factors predictive of ball velocity across youth, high school, collegiate, and professional levels of play. The quality of all included studies was evaluated by 2 reviewers using the Appraisal tool for Cross-Sectional Studies (AXIS). The lack of consistent study design or outcome variables precluded meta-analysis. A total of 584 studies were identified from the initial search with 12 included in final analysis (930 pitchers in total; 429 [46.1%] youth, 164 [17.6%] high school, 153 [16.5%] collegiate and 184 [19.8%] professional) with mean ball velocity of 71.1 mph (114.4 km/h). The average AXIS score was 16 out of a possible 20. The shoulder played a significant role in the generation of velocity-induced torques. Hip and shoulder separation was associated with a 2.6 ± 0.5 mph (4.1 ± 0.8 km/h) increase in velocity, whereas increased shoulder movement of the nonthrowing arm was negatively correlated with initial ball velocity (r2 = 0.798). Furthermore, hip/shoulder separation, decreased movement of the nonthrowing shoulder, trunk power and timing of maximum trunk rotation, increased contralateral trunk tilt and increased sagittal-plane trunk tilt, and decreased knee flexion at ball release were all associated with higher fastball speeds. Multiple upper extremity and trunk kinematic parameters affect ball velocity, with significant contributions from the throwing shoulder and trunk, as well as nondominant arm. Understanding kinematic predictors of faster ball velocity can help guide training regimens.

Repetitive bout of controlled soccer heading does not alter heart rate variability metrics: A preliminary investigation.

There is elevated unease regarding how repetitive head impacts, such as those associated with soccer heading, contribute to alterations in brain function. This study examined the extent heart rate variability (HRV) and cardiac baroreceptor sensitivity (BRS) metrics are altered immediately following an acute bout of soccer heading. Seven male elite soccer players (24.1 ± 1.5 years) completed 40 successful soccer headers in 20-min. The headers were performed under controlled circumstances using a soccer ball launcher located 25 meters away and using an initial ball velocity of 77.5 ± 3.7 km/h (heading condition). An accelerometer (xPatch) on the right mastoid process quantified linear/rotational head accelerations. Participants also completed sham (body contact) and control (non-contact) sessions. A three-lead ECG and finger photoplethysmography characterized short-term spontaneous HRV/cardiac BRS, before and after each condition. The SCAT3 indexed symptom scores pre-post exposures to all three conditions. During the heading condition, cumulative linear and rotational accelerations experienced were 1,574 ± 97.9 g and 313,761 ± 23,966 rad/s2, respectively. Heart rate trended toward an increase from pre- to post-heading (p = 0.063), however HRV metrics in the time-domain (ps > 0.260) and frequency-domain (ps > 0.327) as well as cardiac BRS (ps > 0.144) were not significantly changed following all three conditions. Following the heading condition, SCAT3 symptom severity increased (p = 0.030) with a trend for symptom score augmentation (p = 0.078) compared to control and sham. Whereas, symptoms as measured by the SCAT3 were induced following an acute bout of controlled soccer heading, these preliminary findings indicate they were not accompanied by alterations to autonomic function. Ultimately, this demonstrates further research is needed to understand the physiological underpinnings of alterations in brain function occurring immediately after a bout of soccer heading and how these may, over time, contribute to long-term neurological impairments.

Assessing rugby place kick performance from initial ball flight kinematics: development, validation and application of a new measure

The appropriate determination of performance outcome is critical when appraising a performer’s technique. Previous studies of rugby place kicking technique have typically assessed performance based on ball velocity, but this is not the sole requirement. Therefore, a mathematical model of rugby place kick ball flight was developed to yield a single measure more representative of true performance. The model, which requires only initial ball flight kinematics, was calibrated and validated using empirical place kick data, and found to predict ball position with a mean error of 4.0% after 22 m of ball flight. The model was then applied to the performances of 33 place kickers. The predicted maximum distance, a single performance measure which accounted for initial ball velocity magnitude and direction, and spin, was determined using the model and was compared against ball velocity magnitude. A moderate association in the rank-order of the kicks between these two measures (ρ = 0.52) revealed that the relative success of the kicks would be assessed differently with each measure. The developed model provides a representative measure of place kick performance that is understandable for coaches, and can be used to predict changes in performance outcome under different ball launch or environmental conditions.

Sex and age differences in head acceleration during purposeful soccer heading

ABSTRACTDifferences in head–neck segment mass, purposeful heading technique, and cervical strength and stiffness may contribute to differences in head accelerations across sex and age. The purpose of this study was to compare head acceleration across sex and age (youth [12–14 years old], high school and collegiate) during purposeful soccer heading. One-hundred soccer players (42 male, 58 female, 17.1 ± 3.5 years, 168.5 ± 20.3 cm, 61.5 ± 13.7 kg) completed 12 controlled soccer headers at an initial ball velocity of 11.2 m/s. Linear and rotational accelerations were measured using a triaxial accelerometer and gyroscope and were transformed to the head centre-of-mass. A MANOVA revealed a significant multivariate main effect for sex (Pillai’s Trace = .165, F(2,91) = 11.868, p < .001), but not for age (Pillai’s Trace = .033, F(4,182) = 0.646, p = .630). Peak linear and rotational accelerations were higher in females (40.9 ± 13.3 g; 3279 ± 1065 rad/s2) than males (27.6 ± 8.5 g, 2219 ± 823 rad/s2). These data suggest that under controlled soccer heading conditions, females may be exposed to higher head accelerations than males.

Compression and texture in socks enhance football kicking performance

The purpose of this study was to observe effects of wearing textured insoles and clinical compression socks on organisation of lower limb interceptive actions in developing athletes of different skill levels in association football. Six advanced learners and six completely novice football players (15.4±0.9years) performed 20 instep kicks with maximum velocity, in four randomly organised insoles and socks conditions, (a) Smooth Socks with Smooth Insoles (SSSI); (b) Smooth Socks with Textured Insoles (SSTI); (c) Compression Socks with Smooth Insoles (CSSI) and (d), Compression Socks with Textured Insoles (CSTI). Reflective markers were placed on key anatomical locations and the ball to facilitate three-dimensional (3D) movement recording and analysis. Data on 3D kinematic variables and initial ball velocity were analysed using one-way mixed model ANOVAs. Results revealed that wearing textured and compression materials enhanced performance in key variables, such as the maximum velocity of the instep kick and increased initial ball velocity, among advanced learners compared to the use of non-textured and compression materials. Adding texture to football boot insoles appeared to interact with compression materials to improve kicking performance, captured by these important measures. This improvement in kicking performance is likely to have occurred through enhanced somatosensory system feedback utilised for foot placement and movement organisation of the lower limbs. Data suggested that advanced learners were better at harnessing the augmented feedback information from compression and texture to regulate emerging movement patterns compared to novices.

Development of the simulation model for throwing motion in water polo

The simulation model for the throwing motion in water polo was developed. The input data for the simulation, such as the joint motion and body geometry of the thrower, were acquired in the experiment in which a subject player threw a ball. The simulation reproducing the experiment and the simulation without fluid forces were conducted. From the simulation reproducing the experiment, it was found that the discrepancies between the simulated and experimental displacements were found to be 4 % for the middle point of the waist and 7 % for the wrist of the throwing hand. The simulated initial ball velocity was found to be 19.2 m/s, which was close to the value of 20 m/s reported in the previous studies. From the simulation without fluid forces, 38 % reduction in the initial ball velocity was found.

230 野球の試合における投球されたボールの軌道(動作・設計)

The aim of this study was to describe, in detail, the trajectory of baseballs pitched under game conditions. In six games of a college baseball league, all balls thrown by the pitchers on each team were recorded by using two video cameras. The trajectories of pitched balls were calculated from the video data by a three-dimensional direct linear transformation method. The initial ball velocity, the variation of trajectories, and arrival position of pitched ball were calculated. The results were as follows. 1) Most pitchers threw types of pitches with two or three clearly different ball trajectories, but some pitchers did not. 2) Batters hit balls only in or near strike zone. When thrown a breaking ball, batters occasionally swung at balls below the strike zone. Batters must rapidly make an exact judge on the ball's trajectory, especially for low balls. 3) For some pitchers, the trajectory of fastballs was correlated with arrival position, which should be considered by batters 4) For some pitchers, the initial ball velocity or the vertical variation of trajectory decreased as the pitch count increased. However, this trend was not observed for pitchers who threw a complete game.

The Effect of Driver Mass and Shaft Length on Initial Golf Ball Launch Conditions: A Designed Experimental Study

The influence of golf driver mass and shaft length on initial golf ball launch conditions was investigated. A series of carefully selected player tests were used to isolate the coupled influence of club mass and shaft length on initial ball velocity, spin rates, launch angle, and dispersion of impacts across the clubface. The ranges of selected club masses and shaft lengths were typical of those found in currently available drivers. While longer, lighter clubs generally led to higher ball speeds for most test golfers, those combinations of club mass and club length that minimized spin rates resulted in the greatest estimated total shot distance. Not surprisingly, use of longer drivers led to a slightly larger dispersion of impacts over the clubface. Interestingly, individual golfers tended to miss in the same region of the clubface irrespective of the club length, i.e., they compensated for changes in club mass and length when swinging. Employing the methodology outlined here, it may be possible to tailor golf club designs in order to obtain enhanced golf ball launch characteristics for a range of golfers. Such efforts may facilitate golf club design by establishing relationships between mass and configuration parameters that lead to improved driver performance.

Influence of shaft length on golf driving performance

The aim of this study was to determine how shaft length affects golf driving performance. A range of drivers with lengths between 1.168 m and 1.270 m, representing lengths close to the 1.219 m limit imposed by R&A Rules Limited (2008), were assembled and evaluated. Clubhead and ball launch conditions and drive distance and accuracy were determined for seven category 1 golfers (handicaps 0.21 ± 2.41) who performed shots on a purpose-built practice hole. As shaft length increased from 1.168 m to 1.270 m, initial ball velocity increased (+1.8 m/s, P < 0.01). Ball carry (+4.3 m, P = 0.152) also increased, although not significantly so. Furthermore, as shaft length increased, for all club comparisons there was no decrease in accuracy. Ball launch conditions of spin components and launch angle remained unaffected by shaft length. Launch angle increased (0.8°, F = 1.074, P = 0.362) as driver shaft length increased. Our results show that clubhead and ball velocity together with ball carry tended to increase with no loss of accuracy.

Ball launch conditions for skilled golfers using drivers of different lengths in an indoor testing facility

The displacement of the golf ball struck by a driving club is affected by several player characteristics and equipment parameters and their interrelationships. Some modelling and simulation studies have shown a relationship between shaft length and clubhead speed, supported by a few experimental studies. The aim of the present study was to examine the relationship between driver length and ball launch conditions in an indoor test facility using a ball launch monitor. Nine males considered to be skilled golfers participated in the study. Four driving clubs of total length 117, 119, 124, and 132 cm were assembled from commercially available components and were used to strike golf shots while initial ball velocity, backspin rate, and launch angles were measured. Statistical analysis identified a significant difference in initial launch speed due to club length, a significant difference between participants, but no difference between the trials for a given golfer. A positive trend was noted between backspin and launch angle for all four clubs, and significant inverse associations between initial launch speed and backspin rate and launch angle. However, the combined launch conditions associated with increasing length were not considered optimal, with uncontrolled swingweight and moment of inertia effects considered to be limiting factors.

Shoulder joint movement of the non-throwing arm during baseball pitch—comparison between skilled and unskilled pitchers

The shoulder of a non-throwing arm during a baseball pitch must be in a constant position while the shoulder of the throwing arm moves in a nearly circular path around it. However, it has not been investigated whether a skilled pitch requires less shoulder-joint movement. It was hypothesized that pitchers with less shoulder movement of the non-throwing arm can be considered to have higher skill and to attain higher initial ball velocity. Nine baseball pitchers were used as subjects. The coach classified them into a skilled and an unskilled group. The pitching motions were recorded using two high-speed cameras. The time series of three-dimensional landmark coordinates of the shoulder joint of the non-throwing arm during the baseball pitch were calculated using the direct linear transformation method. The shoulder-joint movement (SJM) index, which expresses the movement (displacement) of the shoulder joint of the non-throwing arm quantitatively, was proposed to compare the SJM at different skill levels and investigate the relationship between SJM and initial ball velocity. The SJM of the skilled pitchers was smaller than that of the unskilled pitchers, and the smaller value of the SJM led to faster initial ball velocity. The data suggest that the less SJM of the non-throwing arm is required to attain a skilled pitch and higher initial ball velocity.

6S スピンを伴うテニスボールとラケットの衝突解析 : ボールのストリングス面への衝突解析

Although the role of ball-spin in tennis is extremely important, the phenomena of the impact with a spin seem difficult to understand. In order to make clear these phenomena, the numerical analysis programs based on finite element method have been developed. The oblique tennis-ball impact with spin on a clamped string face is investigated precisely using the computer simulation, to obtain the effect of strings in the impact on tennis racket. It is found that final angular velocity is higher than one in the case of the impact on a rigid plane surface and increases with initial ball velocity and the effect of initial string tension or impact location on the impact characteristics is small.

The Influence of Isokinetic Muscle Torque Exerted in Various Speeds on Soccer Ball Velocity

Numerous variables influence soccer kick performance and among those initial soccer ball velocity is considered to be important. The purpose of this study was to investigate the correlation between initial ball velocity and two physical characteristics: relative isokinetic torque of the lower extremity and muscle contraction velocity. Eleven elite Greek soccer players age 25.5 +/- 3 years, weight 73.6 +/- 5.6 kg, height 176.5 +/- 5.5 cm, were tested on an isokinetic apparatus at different angular velocities to determine isokinetic muscle torque of the dominant lower extremity. To determine muscle contraction velocity and initial soccer ball velocity a cycling ergometer and a photocell apparatus were used, respectively. Relative isokinetic muscle torque values of the lower extremity were at 30 degrees /sec 3.29 +/- 0.32 Nm/kg, at 90 degrees /sec 2.49 +/- 0.28 Nm/kg, and at 180 degrees /sec 1.75 +/- 0.24 Nm/kg. Muscle contraction velocity was 3.69 +/- 0.27 c/s and initial ball velocity was 27.08 +/- 1.32 m/s. Initial ball velocity correlated significantly with relative isokinetic muscle torque at different angular velocities as follows: at 30 degrees /sec, r = 0.82, p < 0.01; at 90 degrees /sec, r = 0.73, p < 0.02; at 180 degrees /sec, r = 0.64, p < 0.05. Initial ball velocity was also significantly correlated with muscle contraction velocity (r = 0.77, p < 0.01). These results indicate that both physical qualities, i.e., relative isokinetic torque and muscle contraction velocity are significant variables related to soccer ball velocity which is considered to be an important factor of soccer kick performance.J Orthop Sports Phys Ther 1988;10(3):93-96.

Mechanics of Translation and Rotation during Conventional and Handspring Soccer Throw-Ins

This study examined the mechanics of translation and rotation during the conventional and handspring soccer throw-ins. Thirteen male collegiate soccer players were filmed at 100 fps while performing a conventional soccer throw-in for distance. Additionally, two male collegiate and two male youth league soccer players were filmed at 200 fps while performing a handspring throw-in. Analysis of the conventional throw-in revealed that rapid trunk flexion, and shoulder and elbow extension just prior to release appear to make important contributions to the performance variables (initial ball velocity, angle of release, range, angular momentum). Results of the handspring throw-in analysis suggest that the angular momentum generated during the preparatory and ball support phases was transferred to the arms, forearms, and ball during the latter stages of the movement. Although generalization to a larger population is limited, the results of this study suggest that the handspring throw-in technique has the potential to generate greater release velocities and longer throws, thereby enhancing scoring opportunities during throw-in situations.

バスケットボールショットの正確さに及ぼすボール初速度と投射角度の影響

バスケットボールショットの正確さに及ぼすボール初速度と投射角度の影響