Phase Of Throwing Research Articles

Biomechanical Basis of Interval Throwing Programs for Baseball Pitchers: A Systematic Review.

Interval throwing programs are used in rehabilitation of throwing injuries, especially ulnar collateral ligament injuries. Athletes who are rehabilitating begin by throwing on flat ground progressing through increasing distances, number of throws, and intensity of throwing. If the athlete is a baseball pitcher, the flat-ground throwing phase is followed by pitching on a mound at progressively increased effort. The goal is to build back arm strength and capacity with an emphasis on proper mechanics. To determine whether interval throwing progressively builds joint kinetics (specifically, elbow varus torque) to the level required during full-effort baseball pitching. A secondary purpose was to examine the kinematics produced during interval throwing compared to those seen during baseball pitching. Systematic Review. Following PRISMA guidelines, PubMed, Embase, Web of Science, SPORTDiscus, and Google Scholar were systematically searched for biomechanical studies of flat-ground throwing and partial-effort pitching in baseball between 1987 and 2023. Studies that reported the biomechanics of either flat-ground throwing, or partial-effort pitching were included in this review. The AXIS tool was used to assess study quality. Thirteen articles met the inclusion criteria. Ten studies were determined to be of moderate quality, while three studies were deemed high quality. Elbow varus torque during partial-effort pitching was less than during full-effort pitching. Elbow varus torque for most flat-ground throws did not exceed full-effort pitching torque. While most studies showed increased elbow varus torque with increased flat-ground throwing distance, the distance at which elbow varus torque matched or exceeded full-effort pitching elbow varus torque was not consistent.As flat-ground throwing distance increased, shoulder external rotation angle and shoulder internal rotation velocity increased. Arm slot (forearm angle above horizontal) decreased as flat-ground throwing distance increased. For varied effort pitching, shoulder external rotation angle, shoulder internal rotation velocity, elbow extension velocity, and ball velocity increased as effort increased. While the front knee extended slightly from foot contact to ball release in full-effort pitching, the front knee flexed slightly during partial-effort pitching. An interval throwing program progressively builds elbow varus torque up to levels produced in full-effort baseball pitching. While differences exist between interval throwing kinematics and pitching kinematics, the patterns are similar in general. 2.

The Effect of an Exercise Program on the Biomechanics of the Shoulder Girdle in Overhead Shooting in High-level Handball Players

Handball athletes are subjected to high loads, especially during the process of throwing or shooting overhead. These athletes often complain of pain and report unexplained loss of throwing velocity and throwing control. Shoulder dyskinesia and overuse syndrome have been identified as risk factors among elite handball athletes. Understanding the dynamics and kinematics of the throwing phase is vital for the exercise professional. This study evaluates the effect of an interventional exercise program on shoulder girdle biomechanics and overhead shooting. The sample consisted of 20 high level handball athletes from Greece. The athletes were divided into two groups: 10 in the study group, who were given the exercise program, and 10 in the control group, who only engaged in in-team handball training. Before and after the program, the following measurements were performed: a) angular measurements of abduction, adduction, flexion and extension of the shoulder; b) isokinetic evaluation of abduction flexion and adduction extension of the shoulder joint, at three angular velocities (60°/sec, 180°/sec and 300°/sec). Inferential statistics showed that there was a statistically significant difference in angular measurements with a reduction in range of motion for 10 of the study group. In the isokinetic assessment there was a statistically significant difference, in the 180°/sec velocities in flexion and extension, and in the deficit of flexion of both shoulders. In conclusion, the interventional exercise program had, to some extent, a beneficial effect on muscle strengthening of the shoulder girdle. The results of this study may suggest training guidelines, provide important information to exercise professionals, and provide feedback to handball athletes.

A kinetic analysis of the judo osoto-gari technique: relationship to sweeping leg velocity

ABSTRACT The present study characterised supporting leg kinetics (sweeping and pivot legs) during osoto-gari and investigated the relationship between kinetic variables and sweeping leg velocity at sweep contact. Fifteen black belt judoka performed osoto-gari. Motion data were recorded using a Mac3D motion analysis system (250 Hz), and ground reaction force (GRF) data were collected using four force plates (1,000 Hz). During the swing phase, the peak anterior (r = −0.535, p = 0.040) and upward (r = −0.693, p = 0.005) GRFs generated by the sweeping leg and the peak plantar flexion moment (r = 0.548, p = 0.034) and power (r = −0.700, p < 0.005) of the sweeping leg ankle joint significantly correlated with the sweeping leg velocity at sweep contact. During the throwing phase, the peak clockwise moment (r = −0.604, p = 0.017) correlated with the peak sweeping leg velocity. The peak knee extension moment (r = 0.602, p = 0.018), hip flexion moment (r = −0.589, p = 0.021) and knee power (r = −0.618, p = 0.016) of the pivot leg also correlated with the sweeping leg velocity at sweep contact. The results indicated that exertion of the sweeping leg ankle plantar flexors positively contributed to the sweeping velocity. Increasing whole-body rotation by contracting the pivot leg knee extensors is a crucial biomechanical factor in accelerating the sweeping leg at sweep contact.

Poster 185: Flexor Pronator Mass Contribution to Elbow Valgus Stability: A Biomechanical Project

Objectives:Identify the main muscle in the flexor pronator mass (the pronator teres (PT), flexor carpi radialis (FCR), flexor digitorum superficialis (FDS), and flexor carpi ulnaris (FCU)) that contributes most to valgus stability at a greater range of elbow motion (60-150 degrees) than in previous studies.Methods:8 cadaveric elbows in an in vitro biomechanical study were investigated. The specimens were mounted on a custom apparatus from the distal humerus to the fingers. Each muscle group of the flexor pronator mass was relatively loaded based on physiologic cross-sectional area. There were 6 loaded conditions: all loaded, unloaded PT, unloaded FCR, unloaded FDS, unloaded FCU, and all unloaded. A 2 N-m valgus torque was applied at a rate of 1 mm/sec. Valgus angle was measured for each loaded condition, especially between all loaded and one unloaded muscle. This allowed an increase in valgus angle for one unloaded muscle. The higher increase in valgus angle indicated the higher the contribution of that released muscle to valgus stability. This was performed at 60, 90, 120, and 150 degrees of elbow flexion to cover the range at which the UCL tears during the late cocking and early acceleration phases of throwing. The measurements were made in two conditions: first with the UCL intact and second with the UCL resected at the anterior bundle.Results: There was a statistical significance in the mean change in valgus angle at all flexion angles and load conditions when the UCL was intact vs when it was resected (3.76 ± 2.78 SD vs 4.82 ± 2.99 SD degrees).The valgus angle was statistically mostly increased in the “all unloaded” condition when compared to all the other loaded conditions at all flexion angles involving both when the UCL was intact and resected.Unloading one individual flexor pronator muscle did not significantly affect the valgus stability of the elbow.There was a trend towards FDS as being the primary flexor pronator stabilizer when the elbow was taken from an all-loaded condition to one muscle that was unloaded (P value = 0.169).At 150 degrees, the elbow was statistically significantly most stable compared to all the other flexion angles.At 90 degrees, the elbow was most unstable with an increase in valgus angle of 1.2 degrees between intact and resected UCL conditions.At 60 degrees with the UCL resected, there was not a statistical significant difference in valgus angle between all unloaded and unloaded FDS conditions signifying that the FDS contributed most to valgus stability. Conclusions: Physical examination of the UCL is best performed with the elbow at 90 degrees with the forearm in neutral (most unstable out of the flexion angles we tested).At 150 degrees, the elbow is most stable to valgus stress.When the UCL is injured, the FDS appeared to contribute most to valgus stability at 60 degrees out of the four flexor pronator muscles.There was a trend towards FDS as being the primary flexor pronator stabilizer.Rehabilitation of the flexor-pronator mass should focus on the FDS. Figure 1.Figure 2.Table 1.Two-group comparisons of mean valgu angle under different loading conditionsTable 2.Two-group comparisons between all unloaded condition and other loaded conditions at 60˚ elbow flexion with resected UCL.

Elbow Ulnar Collateral Ligament Injuries in Overhead Athletes: An Infographic Summary.

Ulnar collateral ligament (UCL) injuries of the elbow are common in throwing athletes. Given that the UCL's primary function is to provide valgus stability during the deceleration phase of throwing, injury to the UCL will render throwing difficult to nearly impossible.15 Injuries will occur more so in the sports of baseball, softball, and javlineers participating in track and field.5,10,14 Data has indicated that valgus torque reaches 64 N-m and proximal forces as high as 1000 N to prevent elbow distraction. Further, angular velocity across elbow may reach 1900-2480 degrees/second.6,8 Imaging modalities that have the greatest accuracy for diagnosis include magnetic resonance imaging (MRI), MRI-arthrogram, and stress ultrasonography.2,3,11,12 Treatment of UCL injury depends on multiple factors. These include if the injury is a partial tear or complete tear and the location (distal versus proximal) of the partial tear.7 Further, complete tears, as well as partial distal tears, are more likely to undergo surgical intervention.1,13 Treatment decision-making is primarily dependent on following factors: location, severity, if the patient is a throwing athlete, and if the patient is in his or her last year of his/her throwing career due to the length of the rehabilitation process if surgery is pursued.15 Return-to-play success rates when treated conservatively vary from anywhere from 42% to 100%. Conservative treatment includes rest, rehabilitation, platelet-rich plasma injections, and a throwing program.4 Surgical treatment has evolved significantly with various reconstructive techniques and (when indicated) surgical repair with internal bracing. Return-to-play rates are high, ranging from 80% to 95% with low complication rates, but rehabilitation for reconstruction can range from 12-18 months or longer. Therefore, patients must be made aware of the commitment to the rehabilitation process if electing to undergo surgical reconstruction.9.

The Thrower's Shoulder.

The thrower's shoulder has been a subject of great interest for many decades. Different theories have been proposed to clarify the pathophysiology, clinical presentation, and treatment options for this condition. In this review article, we summarize the relevant anatomy and pathophysiology and how these translate into signs, symptoms, and imaging findings. Also, a historical review of the treatment methodologies in the setting of an evolving concept is presented. The initial event in the cascade is thickening and contracture of the posteroinferior capsule resulting from repetitive tensile forces during the deceleration phase of throwing. This is known as "the essential lesion" and is clinically perceived as glenohumeral internal rotation deficit (GIRD), and a Bennett lesion may be found on radiographs. Change in the glenohumeral contact point leads to a series of adaptations that are beneficial for the mechanics of throwing, specifically in achieving the so-called "slot," which will maximize throwing performance. The complexity of the throwing shoulder is the result of an interplay of the different elements described in the cascade, as well as other factors such as pectoralis minor tightness and scapular dyskinesis. However, it is still unclear which event is the tipping point that breaks the balance between these adaptations and triggers the shift from an asymptomatic shoulder to a painful disabled joint that can jeopardize the career of a throwing athlete. Consequences are rotator cuff impingement and tear, labral injury, and scapular dyskinesis, which are seen both clinically and radiographically. A thorough understanding of the pathologic cascade is paramount for professionals who care for throwing athletes. The successful treatment of this condition depends on correct identification of the point in the cascade that is disturbed. The typical injuries described in the throwing shoulder rarely occur in isolation; thus, an overlap of symptoms and clinical findings is common. The rationale for treatment is based on the pathophysiologic biomechanics and should involve stretching, scapular stabilization, and core and lower-body strengthening, as well as correction of throwing mechanics, integrating the entire kinetic chain. When nonoperative treatment is unsuccessful, surgical options should be tailored for the specific changes within the pathologic cascade that are causing a dysfunctional throwing shoulder.

A biomechanics analysis of the judo osoto-gari technique: comparison of black belt and white belt judokas

ABSTRACT The purpose of this study was to determine biomechanical factors for the effective execution of the osoto-gari technique by comparing differences between black belt and white belt judokas. Twenty-two male judokas (12 black belts; 10 white belts) performed osoto-gari, and the motion data were recorded using a Mac3D motion analysis system (250 Hz). The peak angular momentums of the trunk and leg of the uke were larger in the black belts than in the white belts, suggesting that the black belts rotated the uke’s body more effectively than the white belts. During the swing phase, the peak angular velocities of the arms and trunk twist in the black belts were larger compared to the white belts. During the throwing phase, the black belts had substantially greater peak angular velocities of the arms, upper torso, and trunk twist. Additionally, the timing of the peak value of the upper torso and trunk twist of the black belts was closer to sweeping leg contact than that of the white belts. The results can provide coaches with suggestions for improving training protocol design when teaching osoto-gari and for helping novices more efficiently master the technique.

Energy productivity of sugar sorghum in the central part of the Forest-steppe of Ukraine depending on the harvesting time

Due to global climate change, sugar sorghum (Sorghum saccharatum), due to its fast growth rate, early maturation, efcient use of water and limited need for fertilizers, is the most promising plant for biofuel production in the world. The article presents the results of the study on establishing the dependence of sugar sorghum energy performance indicators on varietal characteristics (varieties 'Silosne 42' and 'Favorit' and hybrids 'Dovista' and 'Medoviy F1') and the green biomass harvesting time. The purpose of the research was to establish the influence of varietal characteristics and harvesting time on sugar sorghum energy productivity in the zone of unstable moisture in the Central part of the Forest-Steppe of Ukraine. The research subject is sugar sorghum energy productivity indicators (yield of green biomass; sugar content of juice; yield of biogas, bioethanol, solid biofuel; total energy yield). The studies were carried out during 2016–2020 in the zone of unstable moisture in the central part of the Forest-Steppe of Ukraine in the conditions of the Bila Tserkva Experimental Breeding Station of the Institute of Bioenergy Crops and Sugar Beet of the National Academy of Sciences of Ukraine. It has been established that the highest yield of biofuel and energy (up to 791.8 GJ/ha) is achieved under growing sugar sorghum of the 'Dovista' hybrid, provided that its biomass is collected in the phase of full seed ripeness (early October). It is advisable to start collecting sugar sorghum biomass for biogas after the panicle throwing phase. To ensure the maximum yield of bioethanol, the optimal time for harvesting green biomass of sugar sorghum is the second decade of September – the frst decade of October. The maximum yield of solid biofuel is achieved under harvesting biomass after the phase of waxy ripeness of grain. The formation of the yield of green biomass of sugar sorghum was more influenced by weather conditions (47.4 %), the influence of varietal characteristics (17.8 %) and the timing of harvesting (12.8 %) was less. But the energy yield was most influenced by the timing of harvesting biomass (37.4 %). A close linear correlation between the energy output and the yield of green (R2=0.81) and dry biomass (R2=0.99) was established. The most ecological plasticity in terms of the total energy yield per unit area turned out to be the 'Medoviy F1' hybrid (b=1.62), which indicates the prospects of growing this hybrid under favorable weather conditions and high level of agricultural technology. Key words: sugar sorghum, varietal characteristics, harvesting time, energy yield, biofuel yield, productivity.

Mathematical simulation approach to diagnose performance limiting factor of shot put technique

The applied mathematics simulation for human mot ion is one breakthrough of sports biomechanics in sports science. The optimum rate of energy generated in muscle s and knees, hips, shoulders and wrists play a significant role and influence the throw distance. Kinetic analysis of parabolic path is predominantly determined by the speed of release (V0), angle of release (α) and height of at release (h0 ) at the delivery phase of throwing. The inequality of anthropometry, physical and quality of technique requires coaches to develop mathematical simulation to diagnose performance. This study describes mathematical simulation of speed (V0), angle (α) and height of release (h0) against a throw distance. The 28 male sport students (19.3±1.2 years, weight of 68.2±5.5 kg, height of 169.7±5.4cm) represent a linear shot put (4kg), recorded with 2 HD cameras in sagittal plane and analysed with kinovea software for kinematic motion. There is significant relationship between speed-(p=0.001), angle-(p=0.003) and height of release (p=0.004) with performance. The rate of speed (7.23±0.75ms-1), angle (44.67± 9.19°) and height of release was (194±7.72cm). The greatest shot performance was 12.57m, applies 7.98±0.02ms of speed, 48.59±2.18° of angle and 199.63±2.21cm of height. Mathematical Simulation can be applied to predict shot put performance through kinematic study.

Biomechanical assessment of docking ulnar collateral ligament reconstruction after failed ulnar collateral ligament repair with suture augmentation

Ulnar collateral ligament (UCL) repair with single-strand suture augmentation has been introduced as a viable surgical option for throwers with acute UCL tears. For the original single-strand suture augmentation construct, revision UCL reconstructions can be challenging owing to the bone loss at the site of anchor insertion in the center of the sublime tubercle. This biomechanical study assessed a small-diameter (1.5-mm) ulnar bone tunnel technique for double-strand suture-augmented UCL repair that may be more easily converted to salvage UCL reconstruction if necessary, as well as a salvage UCL reconstruction with a docking technique after a failed primary suture-augmented UCL repair. In 7 fresh-frozen cadaveric upper extremities (mean age, 66.3 years), a custom shoulder testing system was used to simulate the late cocking phase of throwing. The elbow valgus opening angle was evaluated using a MicroScribe 3DLX device for sequentially increasing valgus torque (from 0.75 to 7.5 Nm in 0.75-Nm increments) at 90° of flexion. Valgus angular stiffness (in newton-meters per degree) was defined as the correlation of sequentially increasing valgus torque with the valgus opening angle through simple linear regression (slope of valgus torque - valgus opening angle curve). Four conditions were tested: intact elbow, distal UCL avulsion, primary UCL repair with double-strand suture augmentation using small-diameter bone tunnels, and subsequent docking UCL reconstruction in the same specimen. Load-to-failure tests were performed for primary UCL repair with double-strand suture augmentation and subsequent docking UCL reconstruction. With increasing elbow valgus torque, the valgus opening angle increased linearly in each condition (R2 ≥ 0.98, P < .001). Distal UCL avulsion resulted in significantly decreased angular stiffness compared with the intact UCL (P < .001). Both UCL repair with double-strand suture augmentation and subsequent UCL reconstruction showed significantly increased angular stiffness values compared with distal UCL avulsion (P < .001 and P < .001, respectively). On load-to-failure testing, there was no significant difference in stiffness, yield torque, and ultimate torque between the primary suture-augmented UCL repair and the subsequent UCL reconstruction (P = .11, P = .77, and P = .38, respectively). In all specimens undergoing the small-diameter ulnar bone tunnel technique for double-strand suture-augmented UCL repair, failure occurred by retear of the repaired ligament without causing an ulnar bone bridge fracture. Primary UCL repair with double-strand suture augmentation using small-diameter bone tunnels was able to restore valgus stability. When failure occurs, this technique retains enough cortical bone to permit subsequent docking UCL reconstruction.

Biomechanical assessment of javelin throwing technique

The relevance of research related to search for the optimality of motion technology in various phases of javelin throwing. The questions of biomechanical parameters of javelin throwing are considered at different stages of sports actions in the article. The aim of the work was determination of the rational structure of motor actions in various phases of javelin-throwing. The research was carried out on the basis of an analysis of 764 training and competitive attempts of javelin throwers. The videograms were analyzed using the software «KinoVea». Along with the phase structure of the javelin throwing, the main positions are highlighted, including initial, final and a number of intermediate provisions. To assess the movement, a number of animation positions are highlighted in the main elements of the movement. As the studied parameters were defined time parameters, angular speeds of movement of body parts, moments of inertia and radius of the moment of inertia motion, angular positions in the joints and trajectories of changes in the center of mass of links relative to the general center of mass. The research revealed kinematic and dynamic parameters of the phase structure of javelin throwing. The ranges of angular positions of the body links are revealed in various phases of throwing action. The parameters of the moment and radius of inertia positions of the body links are determined, relative to the common center of mass in different phases of motion, that allows you to predict deviations from the rational trajectory of technology and prevent the possibility of injury. The sequence of movements of the body's links is studied, taking into account the influence of kinematic and dynamic parameters of movement. The findings of research contribute to the selection of the most rational summing training exercises. In addition, it will help reduce the load on the joint and ligamentous apparatus of the thrower.

Effect of Increased Scapular Internal Rotation on Glenohumeral External Rotation and Elbow Valgus Load in the Late Cocking Phase of Throwing Motion

Background: Scapular dyskinesis among throwers is thought to affect kinetic chain function and increase the load demands on the shoulder and/or elbow. However, the biomechanical relationship between scapular orientation and elbow valgus load, which is associated with ulnar collateral ligament (UCL) injury, has not been determined. Purpose: To evaluate the effect of increased scapular internal rotation (IR) and glenohumeral external rotation (GHER) on elbow valgus load in a static simulation of the late cocking phase of throwing. Study Design: Controlled laboratory study. Methods: Seven fresh-frozen male cadaveric upper extremities were used with a custom testing system to simulate the late cocking phase. First, the authors evaluated the effect of increasing scapular IR on maximum GHER and forearm angle (forearm axis relative to the ground). Each parameter was evaluated at 20° to 40° (5° increments) of scapular IR by applying 2.2-N·m external rotation torque to the humerus and 0.75-N·m valgus torque to the forearm. Next, to evaluate elbow valgus stability, the humerus was locked in maximal GHER at 40° of scapular IR, and sequentially increasing torque (0.75-7.5 N·m by 0.75-N·m increments) was applied to the forearm. Valgus angle and joint gap were evaluated at each torque. Results: Increases in scapular IR ≥5° significantly decreased GHER (P < .01). With increasing valgus torque, forearm angle also increased linearly (R2 = 0.85, P < .001). To compensate for the GHER deficit at 40° of scapular IR, a linear regression model showed that 25.3 N·m of valgus torque would be necessary to reach the original forearm position. In the intact condition, applying elbow valgus torque ≥5.25 N·m significantly increased valgus angle and the joint gap (P < .01). Conclusion: Increased scapular IR significantly decreased GHER. Compensation for the GHER deficit significantly increased the elbow valgus load required to reach the same forearm position. Clinical Relevance: Increased scapular IR may increase the risk of elbow UCL injury among throwing athletes.

Kinematic analysis of real and virtual dart games played by stroke patients: A decision tree for neurorehabilitation

Stroke is a pathology that causes several motor and functional impairments. The aim of the study was to realize a kinematic analysis of the elbow joint during real and virtual dart games and to construct decision trees for neurorehabilitation. The sample consisted of 11 hemiparetic patients (8 men), mean age of 51 ± 7 years. Participants made 15 attempts in two dart games (real and virtual). Elbow kinematics was video recorded during the dart throwing phase. Analysis was conducted using Kinovea software, paired Student's t -test and Classification Regression Trees. Patients exhibited a higher elbow extension angle ( P = 0.008) and greater velocity in the real game ( P = 0.005). In the virtual game patients had longer throwing time ( P = 0.021) and better performance (fewer absolute errors) ( P < 0.0001). The decision tree showed that there was a balance between the frequency of patients who played the virtual and real game and displayed elbow extension angles above 157°. Similar frequencies between velocity ≤ 29 cm/s and > 87 cm/s for the virtual and real games were found. In regard to dart throwing time, there was greater frequency of patients with time ≤ 1.37 s for the real game and > 1.37 s for the virtual game. The construction of decision trees showed evidence that the patients can evolve satisfactorily in terms of angulation, velocity and time during virtual game training. Thus, we propose that the virtual dart game may be a useful tool in the neurorehabilitation of patients with chronic stroke, in line with therapeutic objectives and the patient's clinical condition.

Time-motion analysis of goalball players in attacks: differences of the player positions and the throwing techniques

In this study, we aimed to analyse goalball players time-motion variables (distance covered, time spent, maximum and average velocities) in official goalball match attacks, taking into account the attack phases (preparation and throwing), player position (centres and wings) and throwing techniques (frontal, spin and between the legs). A total of 365 attacks were assessed using a video based method (2D) through manual tracking using the Dvideo system. Inferential non-parametric statistics were applied for comparison of preparation vs. throwing phase, wings vs. centres and, among the throwing techniques, frontal, spin and between the legs. Significant differences were found between the attack preparation versus the throwing phase for all player time-motion variables: distance covered, time spent, maximum player velocity and average player velocity. Wing players performed most of the throws (85%) and covered longer distances than centres (1.65 vs 0.31 m). The between the legs and the spin throwing techniques presented greater values for most of the time-motion variables (distance covered, time spent and maximum player velocity) than did the frontal technique in both attack phases. These findings provide important information regarding players’ movement patterns during goalball matches that can be used to plan more effective training.

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.

The Relationship of Throwing Arm Mechanics and Elbow Varus Torque: Within-subject Variation for Professional Baseball Pitchers Across 81,999 Throws

Objectives:Likely due to the high level of strain exerted across the elbow during the throwing motion, elbow injuries are on the rise in baseball. In order to identify at risk athletes and guide post-injury return to throw programs, a better understanding of the variables that influence elbow varus torque is desired. The purpose of this work was to describe the within-subject relationship between elbow varus torque and arm slot, arm speed, and shoulder rotation in professional baseball pitchers.Methods:A total of 81 professional pitchers performed 81,999 throws while wearing a motusBASEBALL sensor and sleeve (Motus Global, Massapequa, NY, USA). 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, arm speed, shoulder rotation, and elbow varus torque. Linear mixed-effects models and likelihood ratio tests were utilized to estimate to the relationship between elbow varus torque and arm slot, arm speed, and shoulder rotation within individual pitchers.Results:All three metrics, arm slot (χ2 = 428, p<0.01), arm speed (χ2 = 57683, p<0.01), and shoulder rotation (χ2 = 1392, p<0.01), were estimated to have a significant relationship with elbow varus torque. Within individual athletes, a 1-Nm increase in elbow varus torque was associated with a 13° decrease in arm slot, a 116°/s increase in arm speed, and an 8° increase in shoulder rotation.Conclusion:Elbow varus torque increased significantly as pitchers increased shoulder rotation during the arm cocking phase and rotational velocity of the arm during the arm acceleration phase of throwing. Thus shoulder flexibility, arm speed, and elbow varus torque (and likely injury risk) are inter-related and should be considered collectively when treating pitchers.

The Effects of Posterior Rotator Cuff Cable Tears on Glenohumeral Biomechanics in a Cadaveric Model of the Throwing Shoulder

Objectives:The rotator cuff cable has been postulated to be the primary load bearing substructure of the superior part of the rotator cuff. Tears of the posterior rotator cable are frequently seen in overhead throwing athletes. Although the biomechanical significance of the anterior rotator cable has been well described, our current understanding of the relevance of the posterior cable is limited. The purpose of this study was to examine how partial-thickness tears and full-thickness tears of the posterior rotator cable would alter glenohumeral biomechanics and kinematics in cadaveric shoulder models.Methods:Eight fresh-frozen cadaveric shoulder specimens were prepared and tested. To simulate the sequence of glenohumeral positions during the throwing motion, specimens were mounted on a custom shoulder testing system with the humerus positioned at 90° of abduction (30° scapular upward rotation, 60° glenohumeral abduction) and tested at 30, 60, 90, and 120 degrees of external rotation. After a circumferential capsulotomy was performed, rotator cuff muscles were loaded based on physiologic cross-sectional area ratios, and testing for each specimen was performed on each the following three conditions: intact posterior cable, partial-thickness (50%) articular-sided posterior cable tear, and full-thickness posterior cable tear. Primary outcome measures tested for each condition under the various degrees of glenohumeral rotation were: 1) anterior and total glenohumeral translation after application of a 30N anterior force; 2) path of glenohumeral articulation; 3) glenohumeral joint force.Results:With a 30N anterior force at 120° of external rotation, there was a significant increase in anterior glenohumeral translation between intact and full-thickness tear specimens (7.28±2.00mm and 17.49±3.75mm, respectively; p<0.05). Similarly, total joint translation at 120° of external rotation significantly increased between intact and full-thickness tear specimens (10.37±3.18mm and 23.37±5.05mm, respectively; p<0.05). No significant differences were apparent at other degrees of rotation (30, 60, 90 degrees), or with partial-thickness tears. Changes in the path of glenohumeral articulation were likewise most evident at 120° of external rotation, with a progressively anterior, inferior, and lateral shift in articulation with sequential sectioning of the posterior cable. Lastly, with regards to alterations in glenohumeral joint force, no significant changes were seen in any of the conditions.Conclusion:In this cadaveric shoulder model of the throwing shoulder, tears of the posterior rotator cuff cable lead to altered glenohumeral biomechanics and kinematics. These changes were most profound at 120° of external rotation, suggesting the importance of an intact posterior cable as a potential stabilizer during the late-cocking phase of throwing.

Effects of Gluteal Fatigue on Shoulder and Scapula Kinematics Among NCAA Division I Softball Athletes

PURPOSE: The purpose of this study was to examine the effects of gluteal fatigue on shoulder and scapula kinematics during all phases of an overhead throw among National Collegiate Athletic Association (NCAA) Division I softball players. METHODS: Ten NCAA Division I softball players (19.89 1.36 years, 172.18 8.52 cm, 74.64 9.98 kg) volunteered. Over the course of three consecutive days athletes performed 60ft (18.3m) throws before and after a gluteal fatigue intervention. Kinematic data to describe the throwing motion were collected using an electromagnetic tracking system at a frequency of 100Hz. Repeated measures ANOVA were used to identify differences pre- and post-fatigue in shoulder elevation, rotation, and plane of elevation, scapula internal/external rotation, up/down rotation, and anterior/posterior tilt at all phases of throwing (foot contact, maximum external rotation, ball release, and maximum internal rotation). RESULTS: There was evidence of gluteal fatigue affecting the throwing motion in the Event x Test interaction for scapular anterior/posterior tilt [F(3,7) = 29.35, p < .01] and scapular up/down rotation [F(3,7) = 5.54, p = .03], and the main effect of Day and Test for shoulder elevation [F(2,8) = 5.01, p = .04, F(1,9) = 21.82, p < .01]. Shoulder plane of elevation, shoulder elevation, and scapula internal/external rotation revealed no statistical significance. CONCLUSION: The overhead throwing motion places great demands on the shoulder joint. Research has shown shoulder injuries are among the most common injuries in overhead throwing athletes. Appropriate sequencing of scapular and shoulder motion reduces the risk of injury as well as improves ball velocity and accuracy.

Kinetics of throwing arm joints and the trunk motion during an overarm distance throw by skilled Japanese elementary school boys

The purpose of this study was to investigate joint kinetics of the throwing arms and role of trunk motion in skilled elementary school boys during an overarm distance throw. Throwing motions of 42 boys from second, fourth, and sixth grade were videotaped with three high-speed cameras operating at 300 fps. Seven skilled boys from each grade were selected on the basis of throwing distance for three-dimensional kinetic analysis. Joint forces, torques, and torque powers of the throwing arm joints were calculated from reconstructed three-dimensional coordinate data smoothed at cut-off frequencies of 10.5–15 Hz and by the inverse dynamics method. Throwing distance and ball velocity significantly increased with school grade. The angular velocity of elbow extension before ball release increased with school grade, although no significant increase between the grades was observed in peak extension torque of elbow joint. The joint torque power of shoulder internal/external rotation tended to increase with school grade. When teaching the overarm throw, elementary school teachers should observe large backward twisting of trunk during the striding phase and should keep in mind that young children, such as second graders (age 8 years), will be unable to effectively utilise shoulder external/internal rotation during the throwing phase.

Baseball Catching Patterns Differ According to Task Constraints

We investigated the effect of task constraints on movement patterns and sought to confirm the finding that the combined movement involved in the transition between catching and throwing emerges through self-organization. We conducted two experiments. In Experiment 1, four participants were required to perform two tasks: catch a launched baseball (catching task) and catch the launched baseball and immediately throw it to a target (catching and throwing task). The balls were launched from five spatial positions, and the participants were instructed to catch the balls with their left hand using a baseball glove. We found that the catching movement differed according to the task and spatial constraints. When the ball was launched close to the body in the catching and throwing task, the shoulder and hip segment angles rotated in the direction of the throw, which resulted in combining the terminal phase of catching with the preparatory phase of throwing. In Experiment 2, two participants were asked to complete the catching and throwing task using the same procedure as in Experiment 1, to investigate the sequence effect. Our findings showed that the spatial position at which the trunk rotation switched direction, that is, hysteresis, differed according to the sequence of positions, suggesting that the combination of two movement patterns, such as catching and throwing, emerged through self-organization.