Throwing Arm Research Articles

Kinematics of Baseball and Softball Catchers Throwing Down to Second Base

PURPOSE: To determine differences in torso and shoulder kinematics in baseball and softball catchers when throwing to second base from their stance or knees. METHODS: Nineteen baseball and softball catchers volunteered to participate (15.63 + 3.47 years; 165.91 + 12.50 cm; 67.71 +17.86 kg). Ten electromagnetic sensors were attached to participants to determine joint positions throughout the throwing motion. Participants were allotted an unlimited time to warm-up, in their catching gear to gain familiarity with the throwing surface. Each participant received a pitch from a pitcher and then completed a series of 10 (5 from knees and 5 from stance) throws to second base located regulation distance from home plate (25.6 m/38.8 m). The kinematic variables analyzed included trunk axial rotation, trunk lateral flexion, shoulder rotation, shoulder elevation, shoulder plane of elevation, pelvis axial rotation, and pelvis lateral flexion. Kinematic variables were analyzed at front foot contact (FC), maximum external rotation (MER), ball release (BR), and maximum internal rotation (MIR). RESULTS: Significant kinematic differences, at each event mark, were identified using a MANOVA followed by paired sample t test, p <.05, to determine the variables that were different between the two types of throws. At FC, trunk axial rotation, shoulder plane of elevation, shoulder elevation, pelvis lateral flexion, and pelvis axial rotation were significantly different. During MER significant differences occurred with trunk flexion, trunk lateral flexion, and pelvis lateral flexion. Ball release produced significant differences in trunk flexion, trunk lateral flexion, and pelvis lateral flexion. Differences at MIR included trunk flexion and trunk lateral flexion. CONCLUSIONS: When the catchers threw from the stance they had a greater degree of shoulder plane of elevation as well as shoulder elevation. Throwing from the stance allowed them to position their throwing arm in a more biomechanically efficient position of shoulder elevation and abduction. It is often assumed that catchers throw from the knees in attempt to produce a quicker release. The results of this study demonstrate that throwing from the knees results in significantly different kinematics than throwing from the stance which could ultimately predispose injury.

Mechanical work, efficiency and energy redistribution mechanisms in baseball pitching

Though baseball pitching is assumed to achieve proper technique in which a great deal of energy is imparted from the trunk to the throwing arm, through a kinetic chain of the entire body, few studies have answered the question of how segmental energy is generated/transferred by muscles and intersegmental joint forces. The purpose of this study was to calculate the mechanical energy produced by the individual joint moments or joint forces in throwing, and further breaking down the joint moments into their muscular and non-muscular interactive moments, assessing their contribution to the generation of mechanical energy. The pitching motion of eight collegiate baseball pitchers was measured using a three-dimensional motion capture system. A model including multiple segments and joints of the throwing arm, non-throwing arm and trunk was developed to establish the relationships between causal muscle work and distributed segmental energy. Using the model, the mechanical energy of each segment was decomposed int...

Playing level achieved, throwing history, and humeral torsion in Masters baseball players

Humeral torsion is thought to be beneficial for throwing. To examine this hypothesis, the throwing and non-throwing arms of 84 Masters baseball players over 35 years of age were measured for humeral torsion, and the highest playing level they achieved and their playing history were recorded. Regression analyses were used to obtain predictors of the highest playing level achieved, throwing arm humeral torsion, and side-to-side difference in humeral torsion. Equations accounting for 36%, 46%, and 12% of the variance respectively were produced. Achieving representative level playing status was associated with the number of seasons played under 16 years of age and having greater throwing arm humeral retrotorsion. Throwing arm humeral retrotorsion was associated with non-throwing arm humeral retrotorsion and an increased number of seasons played before the age of 16 years. A model in which repeated throwing develops an adaptive unilateral bone torsion along with growth in baseball expertise is proposed. Thus dominant arm humeral retrotorsion is a predictor of highest baseball playing level achieved, which in turn is influenced by genetic endowment (as seen in the torsion of the non-throwing arm) and amount of throwing activity, particularly prior to the age of 16.

Reduced humeral torsion predicts throwing-related injury in adolescent baseballers

The amount of torsion in the humerus is determined by both genetic and activity-related factors, and affects the external rotation range of motion available at the shoulder. Previous research has shown athletes participating in throwing sports to have a greater amount of humeral retrotorsion in their dominant arm. The purpose of this study was to investigate the predictive ability of both the genetic and activity-related aspects of humeral torsion regarding throwing-related injury. The amount of humeral torsion in both arms of 35 high level adolescent male baseballers (mean age 16.6 years ± 0.6 years) was measured at study commencement. Significantly increased humeral retrotorsion in the dominant arm compared to the non-dominant arm was found ( p = 0.04). These athletes were followed for a period of 30 months, and any injury to their throwing arm which resulted in missing either a game or practice was recorded. ROC curve analysis was used to determine the predictive ability of humeral torsion with respect to the occurrence of injury to the throwing arm. Of the 35 athletes, 19 suffered a throwing arm injury. AUC values derived from ROC analysis showed humeral torsion in the non-dominant arm (AUC: 0.679, 95% CI: 0.502–0.857), as well as the average of the humeral torsion in both arms (0.692, 0.512–0.873), to be predictive of injury. Torsion in the dominant arm was not a significant throwing arm injury predictor. Thus non-dominant arm humeral torsion (the genetic contribution) was found to be the predictor of throwing arm injury.

Contributions of the muscular torques and motion-dependent torques to generate rapid elbow extension during overhand baseball pitching

Some studies have reported that overarm baseball pitching shows a proximal to distal sequential joint motion including a rapid extension of the elbow. It has been suggested that the rapid elbow extension just before ball release is not due to the action of the elbow extensor muscles, but the underlying mechanisms are not so clear. The purpose of this study was to determine the contributions of each joint muscular- and motion-dependent torques, including the upper trunk and throwing arm joints to generate the rapid elbow extension during baseball pitching. The right handed throwing motions of three baseball pitchers were recorded using five high-speed video cameras and the positional data were calculated using the direct linear transformation method. A throwing arm dynamic model of the upper trunk and throwing arm joints was then used, including 10 degrees of freedom, to calculate the throwing arm joint muscular-, throwing arm and upper trunk joint motion-, gravity-, and external force-dependent components that contribute to the maximum elbow extension angular velocity. The results showed that the rapid elbow extension was primarily due to the upper trunk counterclockwise rotation and shoulder horizontal adduction angular velocity-dependent torques. This study implied that the trunk counterclockwise rotators and shoulder horizontal adductors generate positive torques to maintain the angular velocities of the upper trunk counterclockwise rotation and shoulder horizontal adduction may play a key role in producing the rapid elbow extension.

Paul Richards: The Wizard of Waxahachie

Paul Richards:The Wizard of Waxahachie Steve Treder (bio) Paul Richards isn't in baseball's Hall of Fame, but his career had a scope and impact that has taken others there. One of the most intelligent and accomplished baseball men of all time, more competent than many Hall of Famers, Richards is largely forgotten today, generally unknown to the casual fan. This lack of lasting renown is partly due to a lack of major national exposure. For the great bulk of his career, Richards wasn't working in New York or Los Angeles, and he was part of few championship teams. But it's more than that. Paul Richards was always more respected than popular. A lack of personal charisma with players, colleagues, and bosses is a major reason Richards never became quite the manager or executive he might have; and it might, in fact, be one reason a name-making stint with an elite team never came his way. But Paul Richards's impressive achievements were many in a professional career that spanned half a century as a player, manager, and general manager. Though he never made the Hall of Fame himself, his connection with many Hall of Famers is extraordinary: catching for Carl Hubbell, playing for Connie Mack, managing Brooks Robinson, signing and developing Joe Morgan, and negotiating contracts with Hank Aaron. Without his influence, it's likely that knuckleballers Hoyt Wilhelm and Phil Niekro never would have enjoyed the midcareer blossoming that propelled both to Cooperstown. Waxahachie to New York Waxahachie, Texas, is thirty miles due south of Dallas and forty-two miles southeast of Fort Worth. The town is the seat of Ellis County—broad, flat cattle-ranching and cotton-growing country, cold in the winter and blistering hot in the summer. In this quintessential rural Texas landscape, Paul Rapier Richards was born on November 21, 1908. Raised on a cotton farm, Richards grew up tall (six feet two inches) and slim [End Page 1] and became an outstanding baseball player, a long-ball-hitting infielder with a strong throwing arm. In 1926 at the age of seventeen, he signed his first professional contract, with the Brooklyn Dodgers organization. He played 4 games with the Pittsfield (Massachusetts) Hillies of the Class A Eastern League before being reassigned to a more appropriate level for a rookie teenager: the Class D Eastern Shore League, with the Crisfield, Maryland, Crabbers on the shores of the Chesapeake Bay. Richards did well with the Crabbers, playing second base and hitting .301 with 8 home runs in 58 games, though he also led the league in errors. That October the St. Louis Browns drafted him. Richards played for four years in the Browns' chain, rising as high as Class B. His long, tall frame leveraged an outstanding bat (he led two Minor Leagues in home runs, producing as many as 36 in one season), but at second base, shortstop, or third base, he was exceedingly error prone. As he entered his twenties, Richards filled out, approaching his eventual weight of 185 pounds, and in 1930 the Browns decided to convert him to catcher. It quickly became evident that Richards would develop into an outstanding receiver. The position suited his athletic strengths and his gritty toughness, extraordinary alertness, and intelligence. The Dodgers thought so, at any rate, because they purchased him back from the Browns following the 1930 season. Assigned to Class A Hartford in 1931, Richards hit .301 with 15 home runs, and was a star defender behind the plate. In 1932 he made the jump to the Majors, opening the season as a backup catcher for Brooklyn. But he played very sparingly, getting action in only 3 games (and going 0 for 8 at the plate) before being sold in June to the New York Giants. The Giants farmed Richards out to the Minneapolis Millers of the American Association, Class AA, which was the highest Minor League classification at the time. Richards lit up that league, hitting .361 with 16 homers in 269 at-bats over the balance of the '32 season. He went to the Majors again in 1933 as the Giants' backup behind their outstanding regular Gus Mancuso...

CONTRIBUTIONS OF THE THROWING ARM AND TRUNK MOTIONS TO GENERATE THE RAPID ELBOW EXTENSION MOTION DURING BASEBALL PITCHING

INTRODUCTION The proximal to distal joint sequential motion of the throwing arm, especially the rapid elbow extension that occurs in the acceleration phase, is a common feature in skillful pitching movement. Some studies [1,2] have examined the mechanism that generates the rapid elbow extension in baseball pitching and have suggested that it must result from the motion-dependent interactions of other joint rotations and not from the action of the elbow extensor [2]. However, these analyses dealt with the two-kinetic chain using the simple throwing arm model, and the question of which joint motions including the trunk, upper arm, forearm and hand primarily interact and generate the elbow extension is still to be determined. The purpose of this study was to determine the contributions of the muscular torques of the throwing arm joints and motion-dependent interactions due to the throwing arm joint and trunk rotations to produce maximum elbow extension angular velocity.

Baseball

In this study we compared the kinematic features of the throwing motion between young baseball players of different age groups. Forty‐four Japanese baseball players aged 6.1 to 12.3 years who regularly played baseball, including pitchers and position players, had their throwing actions analyzed three‐dimensionally using high speed videography. Of this sample, 26 players aged above 9 years of age were categorized as the senior group, while the remaining 18 were categorized as the junior group. Senior group throwers had greater height and body mass, and produced a greater ball speed than junior group throwers. The throwing arm movement of senior group throwers was similar to that of adult skilled players. However, in the junior group throwers, the shoulder horizontal adduction angle was larger during the arm acceleration phase, and the maximum angular velocities of elbow extension and shoulder internal rotation occurred later than in senior group throwers. These results indicate that players aged above 9 years can acquire a mature throwing arm movement, while players younger than that will use an immature motion. A possible reason why these differences were shown is that the official baseball is relatively heavy for junior group throwers; they would be better advised to use a lighter ball in throwing practice.

Differences in Pitch Kinematics Between Youth and Professional Baseball Pitchers

PURPOSE: To compare the youth pitching biomechanics with that of elite adult pitchers and to identify differences that might explain common injuries seen in youth pitcher populations. METHODS: Twenty-five professional and 14 youth baseball pitchers were filmed at 120 Hz using two high-speed video cameras. The locations of 21 body landmarks were digitized and their three-dimensional locations were calculated using the DLT method (Abdel-Aziz & Karara, 1971). Three-dimensional position data were filtered using a fourth order Butterworth filter with a cutoff frequency of 13 Hz. From the marker coordinates, the kinematics of the pitching elbow and shoulder were calculated using a standard technique (Fleisig et al., 1996; Werner et al., 1993). Kinematic data were normalized in time to facilitate comparisons and so group mean values could be calculated. RESULTS: The peak shoulder internal rotation and elbow extension angular velocities of the youth pitchers were greater than those of the professional pitchers. Peak shoulder external rotation in youth pitchers was 166 +/− 9 degrees, compared with 182 +/− 13 degrees in professionals (p<0.001). The most striking difference between the groups was in trunk motion. The peak rotational velocities of both the upper trunk and pelvis were greater in youth baseball pitchers than in professional pitchers. Peak upper trunk rotational velocity was 2102+/− 324 deg/s in youth pitchers and 1193 +/− 176 deg/s in professional pitchers (p<0.001). CONCLUSIONS: The data support the observation that youth baseball pitchers control their trunk motion in a less efficient way than elite pitchers (Ireland & Hutchinson, 1995). Peak pelvis rotation velocity occurred near the time of stride foot contact in the professionals, while it occurred much later in the youth pitchers. Proper timing of pelvis and upper trunk rotation are necessary to effectively transfer energy from the trunk to the throwing arm (Fleisig et al., 1996). Therefore, increased trunk rotational velocity may be a compensation for improper timing of segment rotations or insufficient muscle strength in youth pitchers. Improper energy transfer from the trunk to the upper extremity may lead to the increased shoulder internal rotation and elbow extension velocities in youth pitchers compared to the professionals.

Stress Fracture of the Rib in High School Baseball Pitchers Following Conversion into Side Arm Throw Pitching

Stress Fracture of the Rib in High School Baseball Pitchers Following Conversion into Side Arm Throw Pitching

Complex chain of momentum transfer of body segments in the baseball pitching motion

Baseball pitching requires contributions from and interaction among all limb segments. Most previous investigators have concentrated on the throwing arm itself, but the center of mass (COM) and contribution of all segments in the pitching motion have not been studied. The purpose of this study was to investigate the momentum transfer of all body segments in the pitching motion. The kinematics pitching motion data were captured from three experienced pitchers (one is professional, two are amateurs). A ten‐segment body system was modeled in this study. The results showed that the lowest position of the COM during the pitching cycle occurred around the ball release time and the fastest velocity (2.81±0.18 m/sec) of the COM was in the late cocking phase. The trunk and thigh on the throwing side showed the largest linear momentum among all segments in the late cocking phase. The upper throwing arm and forearm had peak linear momentum in the acceleration phase. The trunk also had the largest angular momentum during the pitching cycle and reached the maximum rotational momentum (4.17±1.22 Kg‐m2/sec) in the late cocking phase and medial bending momentum (9.03±5.78 Kg‐m2/sec) at the end of the late cocking phase. From the time sequence of linear momentum changes, especially in the leading direction, the force transfer from the foot to the trunk then through the upper extremity during the pitching motion was identified. The largest change rate of angular momentum found in the trunk meant that the trunk contributed the largest torque in the pitching motion. Better coordination of the body segments in the pitching motion not only enhances performance but also avoids injury. The coordination of motion by athletes in the pitching motion provides a guideline for better coaching and training.

Sequential muscle activity and its functional role in the upper extremity and trunk during overarm throwing

The proximal-to-distal segmental sequence has been identified in many sports activities, including baseball pitching and ball kicking. However, proximal-to-distal sequential muscle activity has not been identified. The aims of this study were to establish whether sequential muscle activity does occur and, if it does, to determine its functional role. We recorded surface electromyograms (EMGs) for 17 muscles from the upper extremity and abdomen during overarm throwing and detected the onset and peak times as indices of muscle activity. The following electromyographic properties were commonly identified in the participants. First, sequential muscle activity was observed from the scapular protractors to the shoulder horizontal flexors and from the shoulder horizontal flexors to the elbow extensor, but not from the elbow extensor to the wrist flexor or forearm pronator. Secondly, the external oblique contralateral to the throwing arm became activated before the ipsilateral external oblique. This sequence is considered to be very effective for the generation of high force and energy in the trunk. Thirdly, the ipsilateral external oblique began its activity almost at foot strike. Finally, the main activity of the rectus abdominis appeared just before the point of release.

THE EFFECT OF PROXIMAL JOINT TORQUE REVERSAL IN A TWO-SEGMENT MODEL OF FLAIL-LIKE THROWING

The purpose was to investigate the possible advantages of torque reversal at the proximal joint in the late stages of the flail-like motion of a two-segment system such as a throwing arm. The maximum velocity of the distal endpoint (vEmax) produced with a shoulder joint reversal torque (with SJRT) was compared to the maximum value produced without a shoulder joint reversal torque (without SJRT). A planar two-segment model of an arm with a fixed proximal endpoint was created. For greater generality, interial parameters for both segments were equal, and based on the average values of the parameters for upper arm and forearm-plus-hand segments. Muscle torque generators at the shoulder and elbow were angular velocity-dependent. A series of simulations were run over a present range of motion with SJRT and without SJRT. Each simulation started with the activation of the shoulder joint torque generator (tSH = 0.000 s). The elbow joint torque generator was activated at various times after the onset of the shoulder joint torque generator (tEL = 0.000 s to 0.250 s), with increments of 0.001 s between successive simulations. For the simulations with SJRT, at various times after the elbow joint torque onset time the shoulder joint torque generator was deactivated and the shoulder joint reversal torque generator was activated (tREV = tEL to 0.250 s), with increments of 0.001 s between successive simulations. The optimal simulation for each condition (with and without SJRT) was considered to be the one that produced the largest vEmax value within the specified range of motion and prior to alignment of the two segments. The optimal simulation with SJRT produced only a slightly larger vEmax value than the optimal simulation without SJRT (12.17 m/s versus 11.44 m/s). In addition, it was found that small errors in the timing of the reversal torque led to smaller values of vEmax than the one produced without SJRT. Taking into account that instantaneous torque reversal is not physiologically possible, the results implied that the use of torque reversal in real life would provide either limited advantage or no advantage at all.

Neurologic Injuries in Baseball Players

In baseball pitchers, injuries to the throwing arm are common due to the extreme stresses placed on the elbow and shoulder joints. These result in peripheral nerve syndromes including ulnar neuropathy at the elbow and suprascapular neuropathy at the shoulder. Recurrent trauma to the axillary artery causing aneurysm and thrombus formation may lead to distal ischemia and stroke. Careful evaluation is required to identify musculoskeletal, neurologic, and vascular causes of upper extremity symptoms in the throwing athlete.

SPORT PERFORMANCE SERIES: The wrestling waist and arm throw

SPORT PERFORMANCE SERIES: The wrestling waist and arm throw

Shoulder Antagonistic Strength Ratios: A Comparison between College-Level Baseball Pitchers and Nonpitchers

The purpose of this study was to investigate the shoulder strength ratios obtained from college-level baseball pitchers and age- and sex-matched nonpitchers. Shoulder flexion/extension and externallinternal rotation strength ratios were assessed in 10 pitchers and 9 nonpitchers. Speeds selected for testing were 180 and 300 degrees /sec on the Cybex /I.@R esults indicated that both pitchers and nonpitchers generated greater peak torque values for the extensors and internal rotators than for the flexors and external rotators of the shoulder. A comparison of shoulder strength ratios between a pitcher's throwing arm and his nonthrowing arm was statistically significant (p < 0.05) for shoulder external/internal rotation at the speeds of 180 and 300 "/set. A comparison of shoulder strength ratios between pitchers and nonpitchers on the nondominant arm was not statistically significant for any of the speeds or directions tested. A comparison of the shoulder strength ratios between pitchers and nonpitchers on the dominant arm was statistically significant (p < 0.05) for all directions and speeds tested. The relationship between shoulder muscle imbalance and injury was discussed. J Orthop Sports Phys Ther 1987;8(9):451-461.

Current concepts in the diagnosis and treatment of shoulder instability in athletes.

Glenohumeral joint instability is a fairly common clinical disorder in athletes, especially in sports that involve the throwing motion. The direction of shoulder instability can be anterior, inferior, posterior, or multidirectional. The cause can be trauma, congenital laxity, or voluntary muscle action. Normal shoulders that have been disrupted by injury respond well to surgical correction. Shoulders that have inherently lax supporting structures, as found in patients with atraumatic and voluntary dislocation, have less consistent success with surgical repair. A common condition encountered in the shoulder of a throwing arm is anterior subluxation, which can be diagnosed by the positive apprehension sign and confirmed by arthroscopy. A torn glenoid labrum is a common injury also. Improvement in the diagnosis and treatment of shoulder disorders has been made recently by arthroscopy which allows direct visualization of the joint; many conditions can now be corrected by means of arthroscopic surgery. Radiographic techniques have also been improved.

Judo Nephropathy

Nine male judo players were studied to evaluate possible renal dysfunction after repeated falls. During a 15-second period a pair of subjects took two steps and one subject performed an arm throw upon his partner. The procedure was then reversed and he was thrown by his partner. This alternating exercise was continued for a total of hundred falls per subject. This protocol was carried out twice by each subject, once on a 10-cm mat, once on a 2.5-cm mat. The compressive forces after falling on both mats were 0 joules and 5,919 joules, respectively. Experimental blood and urine samples were collected at 1, 2, 4, 9, and 24 hours post-trauma. Twenty four-hour glomerular filtration rate (GFR) was significantly inhibited during the traumatic session (2.5-cm mat). For the non-traumatic session (10-cm mat) a 24-hour GFR increase of 73.88% was noted compared to control values. Both experimental sessions demonstrated significantly increased urinary protein. Electrophoretic analysis of the urine showed a marked predominance of albumin. Hematuria present after the traumatic session grossly discolored the urine. All non-traumatic samples failed to demonstrate the presence of red blood cells in pathologic numbers. In this investigation the precipitating factor for hematuria during exercise seemed to depend largely on the severity of the mechanical trauma, and not the exercise per se.

Clinical study of baseball pitchers: correlation of injury to the throwing arm with method of delivery.

Clinical study of baseball pitchers: correlation of injury to the throwing arm with method of delivery.