Ball Release Research Articles

The Effect of Stride Length and Lateral Pelvic Tilt on Elbow Torque in Youth Baseball Pitchers.

High elbow torque during a pitch may contribute to injury risk. Our objective was to determine the pitch mechanics associated with elbow varus torque in youth baseball pitchers. Eighteen male youth pitchers (age = 15.5 ± 1.6years) threw 3 fastballs and 3 change-ups from a windup position while undergoing 3-dimensional kinematic analysis. Independent variables included ball release point distance, stride length, lateral pelvic tilt, and ball velocity. Two multiple regression models, separated by pitch type (fastball, change-up) were used to determine the association of independent variables with peak varus torque at the elbow. Fastball and change-up regression models indicated that stride length (β = 0.301, p = .015; β = 0.46, p < .001, respectively) and lateral pelvic tilt (β = -0.50, p < .001; β = -0.25, p = .04, respectively) were significantly associated with peak elbow varus torque. During fastballs, pitch velocity was significantly associated with peak elbow varus torque (β = 0.38, p = .002), while release point distance was significantly associated with peak elbow varus torque during change-ups (β = -0.33, p = .015). Youth pitchers with longer strides and less lateral pelvic tilt demonstrated greater elbow torque regardless of pitch type, while the association of ball velocity and release point to elbow varus torque was dependent on pitch type.

The Relationship of Throwing Arm Mechanics and Elbow Varus Torque: Within-Subject Variation for Professional Baseball Pitchers Across 82,000 Throws

Background: Likely due to the high level of strain exerted across the elbow during the throwing motion, elbow injuries are on the rise in baseball. To identify at-risk athletes and guide postinjury return-to-throw programs, a better understanding of the variables that influence elbow varus torque is desired. Purpose: To describe the within-subject relationship between elbow varus torque and arm slot and arm rotation in professional baseball pitchers. Study Design: Descriptive laboratory study. Methods: A total of 81 professional pitchers performed 82,000 throws while wearing a motusBASEBALL sensor and sleeve. These throws represented a combination of throw types, such as warm-up/catch, structured long-toss, bullpen throwing from a mound, and live game activity. Variables recorded for each throw included arm slot (angle of the forearm relative to the ground at ball release), arm speed (maximal rotational velocity of the forearm), arm rotation (maximal external rotation of the throwing arm relative to the ground), and elbow varus torque. Linear mixed-effects models and likelihood ratio tests were used to estimate the relationship between elbow varus torque and arm slot, arm speed, and arm rotation within individual pitchers. Results: All 3 metrics—arm slot (χ2 = 428, P < .001), arm speed (χ2 = 57,683, P < .001), and arm rotation (χ2 = 1392, P < .001)—were found to have a significant relationship with elbow varus torque. Within individual athletes, a 1-N.m increase in elbow varus torque was associated with a 13° decrease in arm slot, a 116 deg/s increase in arm speed, and an 8° increase in arm rotation. Conclusion: Elbow varus torque increased significantly as pitchers increased their arm rotation during the arm cocking phase, increased the rotational velocity of their arm during the arm acceleration phase of throwing, and decreased arm slot at ball release. Thus, shoulder flexibility, arm speed, and elbow varus torque (and likely injury risk) are interrelated and should be considered collectively when treating pitchers. Clinical Relevance: It is well established that elbow varus torque is related to ulnar collateral ligament injuries in overhead throwers. This study describes the relationship of arm slot, arm speed, and arm rotation to elbow varus torque in an attempt to identify modifiable risk factors for injury.

Do baseball pitchers improve mechanics after biomechanical evaluations?

The purpose of this study was to determine how often flaws in pitching mechanics identified from biomechanical analysis are corrected. The biomechanics of 46 baseball pitchers were evaluated twice, with an average of 12 months (range 2–48 months) between evaluations. Pitchers were healthy at the time of both evaluations, competing at the high school, college, minor league or Major League level. After warming up, each participant pitched 10 full-effort fastballs. Automated three-dimensional motion analysis was used to compute eight kinematic parameters which were compared with a database of elite professional pitchers. Flaws—defined as deviations from the elite range—were explained to each participant or coach after his initial evaluation. Data from the second evaluation revealed that 44% of all flaws had been corrected. Flaws at the instant of foot contact (stride length, front foot position, shoulder external rotation, shoulder abduction, elbow flexion) or slightly after foot contact (time between pelvis rotation and upper trunk rotation) seemed to be corrected more often than flaws near the time of ball release (knee extension and shoulder abduction). Future research may determine which level athletes or which training methods are most effective for correcting flaws.

Estimation of the Optimal Shoulder Orientation from the Viewpoint of Minimal Shoulder Joint Load in 183 Adolescent Baseball Pitchers

Objectives:Adolescent baseball pitchers are prone to shoulder injury as a result of the extreme force and torque placed on the shoulder, especially tremendous joint force applies to the shoulder near ball release. In our clinical experience, shoulder pain at ball release is common complaint. Little analysis is available about the relationship between shoulder orientation and shoulder joint force at the ball release.Methods:A total of 183 adolescent baseball pitchers (14 to 18 years old) participated after providing written informed consents approved by the hospital’s institutional review board. The procedures to be performed were also explained to their parent(s). Each participant was not currently injured or recovering from an injury at time of testing.For data collection, a set of 14-mm spherical reflective markers was placed on the skin overlying 34 anatomical landmarks. Subsequently, the motion capture automatic digitizing system was used to collect 500-Hz from 7 synchronized cameras was set up around the regulation pitching mound in an indoor laboratory. After stretching and warm-up pitching, each player pitch to 5 fastball pitches. Then, the best pitch thrown for a strike was chosen for kinematic and kinetic analysis.The local coordinate systems were used to calculate 3-dimesional rotation at the shoulder using the typical Eulerian sequence. The standard inverse dynamic equation was used to estimate resultant joint force at throwing shoulder. In order to normalize data between subjects, force was expressed as percent using body weight.To estimate the optimal shoulder orientation at ball release, Rz was defined a shoulder abduction angle, which indicated zero value of shoulder superior/inferior force at ball release by linear regression analysis. Similarly-defined Ry was a shoulder horizontal adduction/abduction angle, which indicated zero value of shoulder anterior/posterior force. Afterward, 2 groups with consideration for variations of shoulder orientations at ball release were created: {A- < Rz - 5, Rz - 5 ≤ A ≤ Rz + 5, Rz + 5 < A+}, {B- < Ry - 5, Ry - 5 ≤ B ≤ Ry + 5, Ry + 5 < B+}. Because shoulder range of motion is generally measured 5 degrees intervals in the orthopaedics. Then, we employed MANOVA to investigate significant differences of averages of inferior/superior and anterior/posterior forces applied to the shoulder at ball release among 2 groups respectively.Results:Superior/inferior force was significantly correlated with shoulder abduction. Also anterior/posterior force was strongly correlated with shoulder horizontal adduction/abduction (Table1). The average superior force at A- and the average inferior force at A+ were significantly greater than that at A. Also, the average anterior force at B- and the average posterior force at B+ were significantly higher than at that B (Table 2).Conclusion:The optimal shoulder orientation for minimizing shoulder force at the instant of ball release was 80.6 degrees of shoulder abduction and 10.7 degrees of shoulder adduction. Excessive shoulder horizontal abduction can lead to SLAP lesion, internal impingement and any more pitching-related shoulder injuries has been published. The results of this study demonstrated that increasing amounts of shoulder horizontal abduction were shown to increase anterior force on the shoulder. Therefore, excessive shoulder horizontal abduction can be responsible for several pitching-related shoulder injuries from the viewpoint of shoulder joint load.Table 1.Correlation coefficient between shoulder orientation and shoulder force at ball release in 183 adolescent baseball pitchers. Shoulder force at ball release (%BW) VariablesAnterior forceCompressive forceSuperior force Ball release Shoulder abduction (°)r = -.09 (P = .233)r = .07 (P = .929)r = -.66 (P < .000) Shoulder horizontal adduction (°)r = -.85 (P < .000)r = .12 (P = .117)r = -.38 (P < .000) Ball speed (m/s)r = .26 (P < .000)r = .60 (P < .000)r = -.07 (P = .347)Table 2.The average (±SD) of shoulder force at ball release among |A-, A, A+| and |B-, B, B+| groupsShoulder force (%BW)A-(A- < Rz - 5)A(Rz - 5 < A < Rz + 5)A+(Rz + 5 < A+)Significantdifferences Ball release Anterior force15.4 ± 26.424.0 ± 20.318.4 ± 23.2NS Compressive force85.3 ± 17.890.4 ± 22.388.8 ± 15.6NS Superior force12.3 ± 14.50.1 ± 15.9-17.1 ± 15.5P < .050 for allShoulder force (%BW)B-(B- < Ry - 5)B(Ry -5 < B < Ry + 5)B+(Ry + 5 < B+)Significantdifferences Ball release Anterior force28.6 ± 17.60.2 ± 14.9-25.4 ±21.9P < .001 for all Compressive force89.3 ±17.290.9 ± 15.970.0 ± 24.0P = .009 for B vs B+P = .013 for B- vs B+ Superior force-7.4 ± 16.8-19.8 ± 18.9-19.6 ± 20.8P < .001 for B vs B-Note: Rz is 80.6 degrees of shoulder abduction and Ry is 10.7 of shoulder horizontal abduction. NS is not significant at the P < .05 level

Electromyographic and Motion Capture Analysis of the Elbow and Forearm in the Overhead Football Throw

Objectives:Muscle activation patterns and the kinetics of overhead throwing have been well described in the baseball athlete but not in the football athlete. Injury patterns vary between these two populations. The purpose of this controlled laboratory study was to describe the muscle activation patterns of the elbow and forearm during the overhead football throw. A better understanding of muscle activation patterns and kinetics will help clinicians understand the difference in injury between these two populations, with an objective of preventing injury in both groups. The hypothesis was that the unique grip and obligatory pronation upon ball release will cause the elbow and forearm muscles to have a unique activation pattern during the overhead football throw.Methods:IRB approval was obtained. Electromyographic (EMG) and motion capture data was collected on eight male quarterbacks. An EMG direct transmission system measuring at 1200 Hz with 9 surface electrodes was used to collect EMG data, with signals normalized to maximal voluntary contraction values for each subject. EMG sensors were placed on the biceps, triceps, brachialis, brachioradialis, anconeus, extensor digitorum communis, flexor digitorum superficialis, pronator teres, and pronator quadratus. A 13 camera motion capture system measuring at 240 Hz with a full body marker set of 39 retro-reflective 9mm markers was used to capture motion data. The throwing motion was divided into four event segments: early cocking, late cocking, acceleration, and follow through.Results:All athletes had NCAA experience and were aged 18-30 years old. The anconeus (26.9%, 36.3%, 57.6%, and 105.8% MVCs), extensor digitorum communis (22.7%, 28.0%, 31.0%, and 42.8% MVCs), and flexor digitorum superficialis (19.4%, 39.3%, 22.3%, and 104.7% MVCs) had high levels of activity throughout all phases of the football throw. The brachioradialis (56.8%MVC) and anconeus (57.6%MVC) were the most active muscles during the acceleration phase. The pronator teres (78.4%MVC), pronator quadratus (90.9%MVC), and flexor digitorum superficialis (104.7% MVCs) have very high levels of activation during the follow through phase.Conclusion:High levels of activity of the anconeus suggest that it functions as a dynamic stabilizer during all phases of the throwing motion. High levels of activity of the extensor digitorum communis and flexor digitorum superficialis suggest that they are important for grip. The pronator teres and pronator quadratus are important at ball release to produce a spiral motion of the football. High activity of the medial sided musculature may impart dynamic stability to the elbow. These findings may explain why quarterbacks have a lower rate of UCL injury and a higher return to play without surgery.

Kinematic patterns underlying disguised movements: Spatial and temporal dissimilarity compared to genuine movement patterns

This study examined the kinematic characteristics of disguised movements by applying linear discriminant (LDA) and dissimilarity analyses to the motion data from 788 disguised and 792 non-disguised 7-m penalty throws performed by novice and expert handball field players. Results of the LDA showed that discrimination between type of throws (disguised vs. non-disguised) was more error-prone when throws were performed by experts (spatial: 4.6%; temporal: 29.6%) compared to novices (spatial: 1.0%; temporal: 20.2%). The dissimilarity analysis revealed significantly smaller spatial dissimilarities and variations between type of throws in experts compared to novices (p<0.001), but also showed that these spatial dissimilarities and variations increased significantly in both groups the closer the throws came to the moment of (predicted) ball release. In contrast, temporal dissimilarities did not differ significantly between groups. Thus, our data clearly demonstrate that expertise in disguising one’s own action intentions results in an ability to perform disguised penalty throws that are highly similar to genuine throws. We suggest that this expertise depends mainly on keeping spatial dissimilarities small. However, the attempt to disguise becomes a challenge the closer one gets to the action outcome (i.e., ball release) becoming visible.

Optical Detection of Impact Contact Times with a Beam Deflection Probe

We present an optical detection technique, called the beam deflection probe, to accurately measure contact times of normal-incidence impacts of steel and sapphire spheres with a transparent glass block. It exploits the deformation of the area that is in a mechanical touch during the rebound. The deformation of the surface acts as a dynamic contact mirror. When illuminated by a laser beam, total internal reflection takes place at the contact mirror, the beam is deflected from it, and its angular deflection history is monitored by a quadrant photodiode. A simple threshold-level data processing of the photodiode signals is used to determine the impact duration. It is shown that the shape of the signal is highly dependent on the location of the impact relative to the center of the laser-beam illuminated area while the determination of the contact time does not depend on the impact position. Using an automated ball release mechanism, the contact time of low-velocity impacts was measured for various ball diameters and approach velocities conforming to the Hertz contact theory. The proposed optical detection of contact times supplements the existing measurement techniques and represents the only alternative to the piezoelectric detection when contact times are to be measured on the microsecond scale.

Does performance level affect initial ball flight kinematics in finger and wrist-spin cricket bowlers?

ABSTRACTSpin bowling plays a fundamental role within the game of cricket yet little is known about the initial ball kinematics in elite and pathway spin bowlers or their relationship to performance. Therefore, the purpose of this study was to record three-dimensional ball kinematics in a large and truly high level cohort of elite and pathway finger-spin (FS) and wrist-spin (WS) bowlers, identifying potential performance measures that can be subsequently used in future research. A 22-camera Vicon motion analysis system captured retro-reflective markers placed on the seam (static) and ball (dynamic) to quantify ball kinematics in 36 FS (12 elite and 24 pathway) and 20 WS (eight elite and 12 pathway) bowlers. Results indicated that FS bowlers delivered the ball with an increased axis of rotation elevation, while wrist-spin bowlers placed greater amounts of revolutions on the ball. It also highlighted that ball release (BR) velocity, revolutions and velocity/revolution index scores for both groups and seam stability for FS bowlers, and seam azimuth angle and spin axis elevation angle for WS bowlers, were discriminators of playing level. As such these variables could be used as indicators of performance (i.e. performance measures) in future research.

Finger forces in fastball baseball pitching

Forces imparted by the fingers onto a baseball are the final, critical aspects for pitching, however these forces have not been quantified previously as no biomechanical technology was available. In this study, an instrumented baseball was developed for direct measurement of ball reaction force by individual fingers and used to provide fundamental information on the forces during a fastball pitch. A tri-axial force transducer with a cable having an easily-detachable connector were installed in an official baseball. Data were collected from 11 pitchers who placed the fingertip of their index, middle, ring, or thumb on the transducer, and threw four-seam fastballs to a target cage from a flat mound. For the index and middle fingers, resultant ball reaction force exhibited a bimodal pattern with initial and second peaks at 38–39ms and 6–7ms before ball release, and their amplitudes were around 97N each. The ring finger and thumb produced single-peak forces of approximately 50 and 83N, respectively. Shear forces for the index and middle fingers formed distinct peak at 4–5ms before release, and the peaks summed to 102N; a kinetic source for backspin on the ball. An additional experiment with submaximal pitching effort showed a linear relationship of peak forces with ball velocity. The peak ball reaction force for fastballs exceeded 80% of maximum finger strength measured, suggesting that strengthening of the distal muscles is important both for enhancing performance and for avoiding injuries.

Are Indian Cricket Fast Bowlers At Risk Of Injury? - A 3d Biomechanical Investigation

Cricket is the most commonly played and followed sport in India. Modern day Cricket demands a high level of performance from the fast bowler who obviously carries the highest risk for injury. 3D motion analysis could be used to prevent injuries by identifying incorrect techniques. Researchers have identified certain key biomechanical variables as predictors of injury in fast bowlers apart from other factors like bowling workload and on-field injuries. Very little such information is available with respect to Indian Cricket fast bowlers despite the huge popularity of the sport here. PURPOSE: To identify injury risks in Indian fast bowlers with respect to key biomechanical variables, using 3D motion analysis. METHODS: 22 male fast bowlers from state & division level Cricket teams between ages 18-30 years underwent 3D motion analysis in a Cricket Biomechanics testing facility. The bowling action was captured with a set of 3D cameras (250fps) and 2D video cameras (125fps). Key biomechanical variables including Delivery Stride Length (SL), Lateral Trunk Flexion at Ball Release (LTF at BR) and Knee Flexion at Front Foot Contact (KF at FFC) were measured. Peak Vertical Ground Reaction Forces (pVGRF) were recorded simultaneously using Force Plates. Data processing & analysis was done with proprietary software using a standard model. Descriptive statistical analysis of results was done. RESULTS: A large proportion of the study population were at risk of injuries (100% had less than optimum SL, 41% had high LTF at BR, 45% had high pVGRF and 45% had lower KF at FFC). Bowling Action Type was found ideal or acceptable in 77%. CONCLUSION: Indian Fast Bowlers, in spite of possessing ideal to acceptable bowling action types, are vulnerable to injury with respect to key biomechanical variables.Figure

Brain negativity as an indicator of predictive error processing: the contribution of visual action effect monitoring.

The error (related) negativity (Ne/ERN) is an event-related potential in the electroencephalogram (EEG) correlating with error processing. Its conditions of appearance before terminal external error information suggest that the Ne/ERN is indicative of predictive processes in the evaluation of errors. The aim of the present study was to specifically examine the Ne/ERN in a complex motor task and to particularly rule out other explaining sources of the Ne/ERN aside from error prediction processes. To this end, we focused on the dependency of the Ne/ERN on visual monitoring about the action outcome after movement termination but before result feedback (action effect monitoring). Participants performed a semi-virtual throwing task by using a manipulandum to throw a virtual ball displayed on a computer screen to hit a target object. Visual feedback about the ball flying to the target was masked to prevent action effect monitoring. Participants received a static feedback about the action outcome (850 ms) after each trial. We found a significant negative deflection in the average EEG curves of the error trials peaking at ~250 ms after ball release, i.e., before error feedback. Furthermore, this Ne/ERN signal did not depend on visual ball-flight monitoring after release. We conclude that the Ne/ERN has the potential to indicate error prediction in motor tasks and that it exists even in the absence of action effect monitoring.NEW & NOTEWORTHY In this study, we are separating different kinds of possible contributors to an electroencephalogram (EEG) error correlate (Ne/ERN) in a throwing task. We tested the influence of action effect monitoring on the Ne/ERN amplitude in the EEG. We used a task that allows us to restrict movement correction and action effect monitoring and to control the onset of result feedback. We ascribe the Ne/ERN to predictive error processing where a conscious feeling of failure is not a prerequisite.

Impact of Increased Football Field Width on Player High-Speed Collision Rate.

High-acceleration head impact is a known risk for mild traumatic brain injury (mTBI) based on studies using helmet accelerometry. In football, offensive and defensive players are at higher risk of mTBI due to increased speed of play. Other collision sport studies suggest that increased playing surface size may contribute to reductions in high-speed collisions. We hypothesized that wider football fields lead to a decreased rate of high-speed collisions. Computer football game simulation was developed using MATLAB. Four wide receivers were matched against 7 defensive players. Each offensive player was randomized to one of 5 typical routes on each play. The ball was thrown 3 seconds into play; ball flight time was 2 seconds. Defensive players were delayed 0.5second before reacting to ball release. A high-speed collision was defined as the receiver converging with adefensive player within 0.5 second of catching the ball.The simulation counted high-speed collisions for 1 team/season (65 plays/game for 16 games/season= 1040 plays/season) averaged during 10 seasons, and was validated against existing data using standard field width (53.3 yards). Field width was increased in 1-yard intervals up to 58.3 yards. Using standard field width, 188 ± 4 high-speed collisions were seen per team per season (18% of plays). When field width increased by 3 yards, high-speed collision rate decreased to 135 ± 3 per team per season (28% decrease; P < 0.0001). Even small increases in football field width can lead to substantial decline in high-speed collisions, with potential for reducing instances of mTBI in football players.

Middle finger and ball movements around ball release during baseball fastball pitching

The objectives of this study were to investigate middle finger movements and dynamics of ball movements around the instant of ball release during baseball pitching. Baseball pitching from an indoor mound among 14 semi-professional pitchers was captured using a motion capture system with 16 high-speed cameras (1,000 Hz). Kinematics of middle finger joints, ball rotation, and force applied to the ball were calculated. The proximal and distal interphalangeal joints continued to extend until the instant of ball release, then abruptly flexed. The abrupt flexion lasted for only several milliseconds, followed by a short extension phase. The finger made a quick double cycle of extension-flexion movement, suggesting that it attained high stiffness resulting from co-contraction. The ball began to roll up to the tip of the finger 8 ± 1 ms before ball release owing to the start of extension or the increased angular velocity of extension for the proximal interphalangeal joint. A mean force of 195 ± 27 N was applied in the proximal direction of the hand at the same time as the beginning of ball rolling, and a mean force of 109 ± 22 N was applied to the throwing direction just before ball release.

Effect of Ball Weight on Speed, Accuracy, and Mechanics in Cricket Fast Bowling.

The aims of this study were: (1) to quantify the acute effects of ball weight on ball release speed, accuracy, and mechanics in cricket fast bowling; and (2) to test whether a period of sustained training with underweight and overweight balls is effective in increasing a player’s ball release speed. Ten well-trained adult male cricket players performed maximum-effort deliveries using balls ranging in weight from 46% to 137% of the standard ball weight (156 g). A radar gun, bowling target, and 2D video analysis were used to obtain measures of ball speed, accuracy, and mechanics. The participants were assigned to either an intervention group, who trained with underweight and overweight balls, or to a control group, who trained with standard-weight balls. We found that ball speed decreased at a rate of about 1.1 m/s per 100 g increase in ball weight. Accuracy and bowling mechanics were not adversely affected by changes in ball weight. There was evidence that training with underweight and overweight balls might have produced a practically meaningful increase in bowling speed (>1.5 m/s) in some players without compromising accuracy or increasing their risk of injury through inducing poor bowling mechanics. In cricket fast bowling, a wide range of ball weight might be necessary to produce an effective modified-implement training program.

Automated vision occlusion-timing instrument for perception-action research.

Vision occlusion spectacles are a highly valuable instrument for visual-perception-action research in a variety of disciplines. In sports, occlusion spectacles have enabled invaluable knowledge to be obtained about the superior capability of experts to use visual information to guide actions within in-situ settings. Triggering the spectacles to occlude a performer's vision at a precise time in an opponent's action or object flight has been problematic, due to experimenter error in using a manual buttonpress approach. This article describes a new laser curtain wireless trigger for vision occlusion spectacles that is portable and fast in terms of its transmission time. The laser curtain can be positioned in a variety of orientations to accept a motion trigger, such as a cricket bowler's arm that distorts the lasers, which then activates a wireless signal for the occlusion spectacles to change from transparent to opaque, which occurs in only 8ms. Results are reported from calculations done in an electronics laboratory, as well as from tests in a performance laboratory with a cricket bowler and a baseball pitcher, which verified this short time delay before vision occlusion. In addition, our results show that occlusion consistently occurred when it was intended-that is, near ball release and during mid-ball-flight. Only 8% of the collected data trials were unusable. The laser curtain improves upon the limitations of existing vision occlusion spectacle triggers, indicating that it is a valuable instrument for perception-action research in a variety of disciplines.

Changes in Lower Extremity Kinematics and Temporal Parameters of Adolescent Baseball Pitchers During an Extended Pitching Bout

Background: Few studies have investigated detailed 3-dimensional lower extremity kinematics during baseball pitching in adolescent athletes during extended play. Changes in these parameters may affect performance outcomes. Purpose: To investigate whether adolescent baseball pitchers experience changes in lower extremity kinematics and event timing during a simulated game-length pitching bout. Study Design: Descriptive laboratory study. Methods: Twelve male adolescent pitchers (aged 14-16 years) threw 6 sets of 15 fastball pitches from an artificial pitching mound to a target at regulation distance. Joint angles and angular velocities at the hip, knee, and ankle of both legs were collected throughout the phases of the pitching cycle as well as stride length, pelvis orientation, pitch duration, timing of foot contact and ball release, ball speed, and pitching accuracy. Paired t tests (P < .05) were used to compare the dependent variables between the last 5 pitches of the second (baseline) and sixth (final) sets. Results: During the stride phase, decreased maximum angular excursions for hip extension (baseline: 14.7° ± 9.8°; final: 11.6° ± 10.3°; P < .05) and ankle plantar flexion (baseline: 30.2° ± 14.5°; final: 24.2° ± 15.3°; P < .05) as well as maximum angular velocity for knee extension (baseline: 144.9 ± 63.3 deg·s−1; final: 121.7 ± 62.0 deg·s−1; P < .05) were observed between sets in the trailing leg. At foot contact, pitchers had decreased hip flexion (baseline: 69.5° ± 10.1°; final: 66.5° ± 11.8°; P < .05) and increased hip abduction (baseline: 20.7° ± 8.9°; final: 25.4° ± 6.0°; P < .05) in the leading leg in the final set. Compared with the baseline set, ball speed significantly decreased in the final set (29.5 ± 2.5 m·s−1 vs 28.3 ± 2.5 m·s−1, respectively; P < .05). Conclusion: Kinematic changes and decreased ball speeds observed in the final set suggest that adolescent pitchers are unable to maintain lower extremity kinematics and performance as a result of extended play. Clinical Relevance: The results from this study may warrant further investigation into how altered lower extremity kinematics may affect trunk and upper extremity function, performance, and risk of injuries during pitching in adolescent athletes, particularly during actual game play.

The Relationship Between Pitching Mechanics and Injury: A Review of Current Concepts.

Context:The overhand pitch is one of the fastest known human motions and places enormous forces and torques on the upper extremity. Shoulder and elbow pain and injury are common in high-level pitchers. A large body of research has been conducted to understand the pitching motion.Evidence Acquisition:A comprehensive review of the literature was performed to gain a full understanding of all currently available biomechanical and clinical evidence surrounding pitching motion analysis. These motion analysis studies use video motion analysis, electromyography, electromagnetic sensors, and markered motion analysis. This review includes studies performed between 1983 and 2016.Study Design:Clinical review.Level of Evidence:Level 5.Results:The pitching motion is a kinetic chain, in which the force generated by the large muscles of the lower extremity and trunk during the wind-up and stride phases are transferred to the ball through the shoulder and elbow during the cocking and acceleration phases. Numerous kinematic factors have been identified that increase shoulder and elbow torques, which are linked to increased risk for injury.Conclusion:Altered knee flexion at ball release, early trunk rotation, loss of shoulder rotational range of motion, increased elbow flexion at ball release, high pitch velocity, and increased pitcher fatigue may increase shoulder and elbow torques and risk for injury.

Pitching form determines probabilistic structure of errors in pitch location

ABSTRACTAccording to recent motor control studies, it is important to know probabilistic structure of his/her own motor errors to choose an optimal motor plan (i.e., where you aim at) to maximise the expected gain. In this study, we questioned if pitching form determines the probabilistic structure of pitching errors in baseball pitchers. Eighteen collegiate baseball pitchers with various pitching forms including right- and left-handed overarm, sidearm and underarm throwers threw 100 pitches aiming at a target located 90 cm above the ground. Two dimensional distribution of pitch location was fitted by using bivariate normal distribution and 95% confidence ellipse was calculated. In order to quantify the pitching form, the direction of the throwing arm trajectory in frontal plane was calculated. The direction of the long axis was dependent on each participant’s pitching form (e.g., right overarm pitchers pitched along a right-up–left-down ellipse and left overarm pitchers pitched along a left-up–right-down ellipse). This was confirmed by circular correlation analysis (P = 0.98). These results suggest that different mechanisms, potentially errors in pitching mechanics and errors in ball release timing, might contribute to errors along the long axis and those along the short axis.

Differences in Throwing Kinematics among Youth Baseball Pitchers and Football Quarterbacks

The purpose of this study was to examine throwing kinematics of youth baseball pitchers and football quarterbacks. Eighteen pitchers (13.6 ± 1.3 years; 169.3 ± 8.0 cm; 62.3 ± 10.2 kg) and fifteen quarterbacks (14.3 ± 1.6 years; 174.9 ± 7.9 cm; 69.1 ± 14.0 kg) participated. Pitchers threw three fastballs to a catcher (46 ft; 14.0 m), while quarterbacks threw three 15 yard (13.7 m) passes to a receiver. Baseball pitchers displayed significantly greater trunk flexion at maximum external rotation (MER), ball release (BR) and maximum internal rotation (MIR) (p<0.001, p=0.003, p=0.007); as well as greater trunk rotation opposite throwing arm side at BR (p=0.048). Football quarterbacks displayed greater trunk rotation to throwing arm side at MER (p=0.002); shoulder horizontal adduction at FC (p=0.004); shoulder external rotation at BR (p=0.036); and elbow flexion at FC and MER (p=0.018, p=0.044). Trunk kinematic differences may be the result of pitchers throwing from a mound versus flat ground, just as upper extremity kinematic differences could be the result of the weight and shape of the ball.

Biomechanical Comparison of Three Perceived Effort Set Shots in Team Handball Players.

Plummer, HA, Gascon, SS, and Oliver, GD. Biomechanical comparison of three perceived effort set shots in team handball players. J Strength Cond Res 31(1): 80-87, 2017-Shoulder injuries are prevalent in the sport of team handball; however, no guidelines currently exist in the implementation of an interval throwing protocol for players returning from an upper extremity injury. These guidelines exist for the sport of baseball, but team handball may present additional challenges due to greater ball mass that must be accounted for. The purpose of this study was to examine kinematic differences in the team handball set shot at 50, 75, and 100% effort which are common throwing intensities in throwing protocols. Eleven male team handball players (23.09 ± 3.05 years; 185.12 ± 8.33 cm; 89.65 ± 12.17 kg) volunteered. An electromagnetic tracking system was used to collect kinematic data at the pelvis, trunk, scapula, and shoulder. Kinematic differences at the shoulder, trunk, and pelvis were observed across effort levels throughout the set shot with most occurring at ball release and maximum internal rotation. Significant differences in ball speed were observed between all 3 effort level shots (p < 0.001). Team handball players are able to gauge the effort at which they shoot; however, it cannot be assumed that these speeds will be at a certain percentage of their maximum. The results of this study provide valuable evidence that can be used to prepare a team handball player to return to throwing activities.