Relationships Between Lower Extremity Power and Fastball Spin Rate and Ball Velocity in Professional Baseball Pitchers.

ABSTRACT: Wong, R, Laudner, K, Amonette, W, Vazquez, J, Evans, D, and Meister, K. Relationships between lower extremity power and fastball spin rate and ball velocity in professional baseball pitchers. J Strength Cond Res 37(4): 823-828, 2023-Lower extremity power has been hypothesized to increase ball spin and velocity during pitching in baseball. Therefore, the purpose of this study was to determine the relationship between lower extremity power and fastball spin rate in professional baseball pitchers. A secondary purpose was to determine the relationship between lower extremity power and ball velocity. Fifty-three asymptomatic professional pitchers participated (24.5 ± 3.6 years; 189.9 ± 6.1 cm; 92.6 ± 10.3 kg). Each athlete performed 3 separate bilateral jump tests on force plates: countermovement jump (CMJ), squat jump (SJ), and drop jump (DJ). The average fastball spin rate and ball velocity for each pitcher was calculated using a 3-dimensional Doppler radar and video system over the course of a competitive season. Standard multiple regression analyses ( p ≤ 0.05) revealed significant relationship between ball spin and summation of variables for the CMJ (peak force, peak power, rate of power development, and jump height) ( R2 = 0.20, F = 3.1, p = 0.03). However, no individual variable was significantly associated ( p > 0.09). There was also a significant amount of variance in ball spin explained by summation of variables for the SJ (peak force, peak power, rate of power development, and jump height) ( R2 = 0.19, F = 2.8, p = 0.04); rate of power development was the only variable that significantly predicted ball spin within this model ( B = 0.27; 95% confidence interval [CI]: 0.003-0.75, p = 0.05). Ball spin was not associated with summation of DJ variables (peak power, rate of power development, jump height, reactive strength index, and total peak power in watts) ( R2 = 0.18, F = 2.0, p = 0.09). For ball velocity, there were no significant relationships for the summation of either the CMJ variables ( R2 = 0.10, p = 0.28) or the SJ variables ( R2 = 0.07, p = 0.44). However, there was a significant amount of variance in ball velocity explained by summation of variables for the DJ ( R2 = 0.30, F = 3.93, p = 0.005). The reactive strength index was the sole unique contribution to this model ( B = 1.18; 95% CI: -10.34 to 2.36, p = 0.002). These findings highlight the relevance of increased lower extremity power on increasing fastball spin rate and ball velocity.

Relationships Between Clinically Measured Upper-Extremity Physical Characteristics and Ball Spin Rate in Professional Baseball Pitchers.

ABSTRACT: Wong, R, Laudner, K, Evans, D, Miller, L, Blank, T, and Meister, K. Relationships between clinically measured upper-extremity physical characteristics and ball spin rate in professional baseball pitchers. J Strength Cond Res 35(5): 1331-1337, 2021-During baseball pitching, physical characteristics of the shoulder, elbow, wrist, hand, and fingers have been hypothesized to be critical to creating ball spin. The purpose of this study was to determine if pitchers with greater shoulder, elbow, wrist, and finger range of motion (ROM), arm and hand length, wrist strength, or grip and finger strength would produce greater ball spin than those with less physical characteristics. Ninety, asymptomatic, professional baseball pitchers participated (age = 24.5 ± 3.9 years; height = 189.9 ± 6.1 cm; body mass = 92.6 ± 10.6 kg). Goniometers and a digital level were used to measure shoulder, elbow, wrist, and finger ROM, a tape measure was used to assess arm and hand lengths, and handheld dynamometers were used to measure wrist, grip, and finger strength. Ball spin was measured using a 3-dimensional Doppler radar and video system. Standard multiple regression analyses showed no significant relationships existed between ball spin and any of the upper-extremity ROM or limb length variables (R2 = 0.01-0.03; p = 0.40-0.94). However, there was a significant relationship for the summation of wrist strength (R2 = 0.24, p = 0.03). Both time to wrist extension strength {B = 0.50 (95% confidence interval [CI]: 0.23-0.76), p = 0.001} and radial deviation strength (B = 0.41 [95% CI: 0.15-0.66], p = 0.002) were significant predictors within this model. These results demonstrate that the rate of ball spin during a pitch may be partially altered by increasing wrist extension acceleration and radial deviation strength. However, the subsequent clinical measurements of shoulder, elbow, wrist, and finger ROM, arm and hand length, and grip and finger strength were not associated with ball spin.

Lumbopelvic Control and the Development of Upper Extremity Injury in Professional Baseball Pitchers.

BACKGROUND: The baseball-throwing motion requires a sequential order of motions and forces initiating in the lower limbs and transferring through the trunk and ultimately to the upper extremity. Any disruption in this sequence can increase the forces placed on subsequent segments. No research has examined if baseball pitchers with less lumbopelvic control are more likely to develop upper extremity injury than pitchers with more control. PURPOSE: To determine if baseball pitchers who sustain a chronic upper extremity injury have less lumbopelvic control before their injury compared with a group of pitchers who do not sustain an injury. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A total of 49 asymptomatic, professional baseball pitchers from a single Major League Baseball organization participated. Lumbopelvic control was measured using an iPod-based digital level secured to a Velcro belt around each player's waist to measure anteroposterior (AP) and mediolateral (ML) deviations (degrees) during single-leg balance with movement and static bridge maneuvers. During a competitive season, 22 of these pitchers developed upper extremity injuries, while the remaining 27 sustained no injuries. Separate 2-tailed t-tests were run to determine if there were significant differences in lumbopelvic control between groups (P < .05). RESULTS: There were no significant between-group differences for the stride leg (nondominant) during the bridge test in either the AP (P = .79) or the ML (P = .42) directions, or either direction during the drive leg bridge test (P > .68). However, the injured group had significantly less lumbopelvic control than the noninjured group during stride leg balance in both the AP (P = .03) and the ML (P = .001) directions and for drive leg balance in both the AP (P = .01) and the ML (P = .04) directions. CONCLUSION: These results demonstrate that baseball pitchers with diminished lumbopelvic control, particularly during stride leg and drive leg single-leg balance with movement, had more upper extremity injuries than those with more control. Clinicians should consider evaluating lumbopelvic control in injury prevention protocols and provide appropriate exercises for restoring lumbopelvic control before returning athletes to competition after injury. Specific attention should be given to testing and exercises that mimic a single-limb balance task.

The effects of restricted glenohumeral horizontal adduction motion on shoulder and elbow forces in collegiate baseball pitchers.

BACKGROUND: Decreased glenohumeral (GH) horizontal adduction range of motion (ROM) among baseball pitchers has been associated with the development of various shoulder and elbow pathologies. No research has examined how this tightness may affect the forces placed on the shoulder and elbow during the pitching motion. METHODS: Fifty-five asymptomatic National Collegiate Athletic Association Division I baseball pitchers participated. Twenty-five participants had -10° or less horizontal adduction ROM in their throwing shoulder. The remaining 30 participants had greater than -10° of horizontal adduction. A digital inclinometer was used to measure GH horizontal adduction, internal rotation, and external rotation ROM while in 90° of shoulder abduction. Forces produced in the throwing shoulder and elbow were assessed with a 3-dimension, high-speed video capture system and based on the sum of angular momenta of the kinetic chain segments around the center of gravity. Separate 2-tailed t tests were run to determine significant differences between groups (P < .05). RESULTS: Both groups presented with significant bilateral differences in their total arcs of motion (P < .04). This suggests that the loss of horizontal adduction in these groups was at least partially due to soft tissue tightness. There were no significant between-group differences for shoulder external rotation torque or shoulder and elbow distraction (P > .10). The restricted ROM group had significantly more shoulder abduction torque (P = .04), shoulder horizontal abduction torque (P = .004), elbow flexion torque (P = .002), and elbow valgus torque (P = .02) compared with the control group. CONCLUSIONS: These results demonstrate that collegiate pitchers with -10° or less of horizontal adduction ROM in their throwing shoulder create significantly more shoulder abduction and horizontal abduction torque, as well as more elbow flexion and valgus torque, during the pitching motion than those with more ROM.

POSTERIOR SHOULDER TIGHTNESS AND SUBACROMIAL IMPINGEMENT CHARACTERISTICS IN BASEBALL PITCHERS: A BLINDED, MATCHED CONTROL STUDY.

BACKGROUND: Baseball pitchers frequently develop varying levels of posterior shoulder tightness (PST) and often present with characteristics associated with subacromial impingement. PURPOSE: To determine if a group of baseball pitchers with excessive PST (bilateral internal rotation ROM difference >18 ° and bilateral total arc of motion difference >5 °) have differences in subacromial joint space, forward scapular posture, or glenohumeral elevation range of motion (ROM) when compared to a control group. STUDY DESIGN: Descriptive, cross-sectional study. METHODS: Thirty-five asymptomatic professional baseball pitchers with excessive PST were matched with 35 pitchers with acceptable levels of PST. The investigators measured subacromial space using diagnostic ultrasound, glenohumeral elevation ROM using a digital goniometer, and scapular posture using a double square, and were blinded to the group of each participant. Separate t-tests were used to determine significant differences between groups (p < 0.05). RESULTS: The excessive PST group presented with significantly less subacromial space (p = .0007) and glenohumeral elevation ROM (p = .03) compared to the acceptable level PST group. The excessive PST group also had significantly more forward scapular posture than the control group (p = .03). CONCLUSION: The baseball pitchers with excessive PST had less subacromial space and glenohumeral elevation ROM, as well as more forward scapular posture in their throwing arms compared to pitchers with acceptable levels of PST. LEVEL OF EVIDENCE: 3.

The influence of lumbopelvic control on shoulder and elbow kinetics in elite baseball pitchers.

BACKGROUND: Research has shown that diminished lumbopelvic control has a negative effect on pitching performance and can lead to more days on the disabled list. Despite the identified correlation between lumbopelvic control and injury, there is no research that has shown whether insufficient lumbopelvic control increases the force placed on the throwing arm. METHODS: Forty-three asymptomatic, National Collegiate Athletic Association Division I and professional minor league baseball pitchers participated. We measured the bilateral amount of anterior-posterior lumbopelvic tilt during a single-leg stance trunk stability test. We measured the shoulder and elbow kinetics of the throwing arm during the pitching motion using a 3-dimensional, high-speed video capture system. We used 2-tailed Pearson product-moment correlation coefficients (r) to determine the strength of the relationships between variables (P < .05). RESULTS: There were no significant relationships between the stride leg and any of the pitching kinetic variables (r < 0.23, P > .14). Similarly, there were no significant relationships between the drive leg and maximum shoulder distraction force, shoulder external rotation torque, or elbow distraction force (r <-0.24, P > .13). However, the drive leg did have significant relationships with both maximum shoulder horizontal torque (r = 0.44, P = .003) and elbow valgus torque (r = 0.46, P = .002). CONCLUSIONS: Our results show that a relationship exists between lumbopelvic control of the drive leg and both shoulder horizontal torque and elbow valgus torque during the throwing motion. Because of these relationships, clinicians should consider incorporating lumbopelvic control training exercises to minimize the kinetic force placed on the throwing shoulder and elbow during the pitching motion.

Descriptive Profile of Lumbopelvic Control in Collegiate Baseball Pitchers.

Laudner, K, Wong, R, Latal, J, and Meister, K. Descriptive profile of lumbopelvic control in collegiate baseball pitchers. J Strength Cond Res 32(4): 1150-1154, 2018-Throwing a baseball requires the transmission of forces generated in the lower extremity, through the trunk, then to the upper extremity, and ultimately out through the ball. Disruptions in this kinetic chain, specifically in lumbopelvic control, have been associated with decreased pitching performance and increased risk of injury. The purpose of this study was to establish normative data of lumbopelvic control among collegiate baseball pitchers. Data were compared bilaterally and with a group of nonthrowing physically active individuals. Eighteen asymptomatic pitchers and 30 nonthrowing subjects participated in this study. Each subject performed 6 separate tests bilaterally: single-leg balance, single-leg mini-squat, and static single-leg bridge. An iPod-based tilt sensor was placed around the waist of each subject and used to determine the amount of anterior-posterior lumbopelvic tilt during each test. Independent t tests showed that neither group had any bilateral differences in lumbopelvic control (p > 0.10). The groups had similar lumbopelvic tilt values during the single-leg balance (p > 0.08) and mini-squat tests (p > 0.72), but a significant difference during the bridge maneuver. For this test, the pitchers had less lumbopelvic control than the control group for both the lead leg (p = 0.003) and trail leg (p = 0.01). The descriptive values of this study may assist in designing lumbopelvic conditioning programs with the intent of enhancing pitching performance, as well as in the prevention, evaluation, and treatment of various injuries associated with lumbopelvic control deviations.

Strong Correlation of Upper-Extremity Blood-Flow Volume With Grip Strength While in a Provocative Shoulder Position in Baseball Pitchers.

CONTEXT: Baseball players, specifically pitchers, with symptomatic neurovascular occlusion often initially complain of arm fatigue and loss of ball control and velocity. As the compression continues complaints may manifest in dull pain, paresthesia, and decreased grip strength. OBJECTIVE: To determine the correlation between upper-extremity blood-flow volume and grip strength among baseball pitchers. DESIGN: Cross-sectional. SETTING: Athletic training room. PARTICIPANTS: 66 professional baseball pitchers (age 21.6 ± 2.0 y, height 186.9 ± 5.7 cm, mass 91.3 ± 10.9 kg) before the start of spring training. MAIN OUTCOME MEASURES: Diagnostic ultrasound was used to measure upper-extremity blood-flow volume with the throwing shoulder in a resting position and in a provocative position. Grip strength was measured with participants seated and their throwing-arm elbow flexed to 90°. Pearson product-moment correlation coefficients were used to determine the strength of the relationships between blood-flow volume in the 2 arm positions and grip strength (P < .05). RESULTS: No significant relationship was found between blood-flow volume in the resting position and grip strength (r = .03, P = .81); however, a strong positive correlation was found in the 2nd provocative position (r = .67, P = .001). This relationship indicates that as blood-flow volume tested in a provocative shoulder position decreases, so does grip strength. CONCLUSION: A strong positive relationship was found in pitchers, demonstrating that as upper-extremity blood-flow volume while in the provocative shoulder position decreases, so does grip strength.

Epidemiology and Impact of Knee Injuries in Major and Minor League Baseball Players.

Few studies have explored the frequency and impact of lower extremity injuries, such as those to the knee, among professional baseball players. The purpose of this study was to detail the epidemiology of knee injuries in Major League Baseball (MLB) and Minor League Baseball (MiLB) players during the 2011-2014 seasons. It was hypothesized that knee injuries are a common occurrence in these athletes, and represent a significant source of time away from play. The MLB Health and Injury Tracking System database was searched to identify all patients diagnosed with knee injuries during the 2011-2014 seasons. All injuries that occurred during the preseason, regular season, and postseason that resulted in time away from play were included. Injury data analyzed included total number of knee injuries, specific diagnoses, injury mechanisms, locations, player positions, and time lost. Descriptive statistics were conducted and injury rates per athlete-exposures were calculated. During the 2011-2014 seasons, a total of 2171 knee injuries occurred in MLB and MiLB players, representing 6.5% of all injuries in professional baseball. The knee injury rate across both the MLB and MiLB was 1.2 per 1000 athlete-exposures. The mean number of days missed per injury across both leagues was 16.2 with a total of 30,449 days of missed play amongst all athletes over the 4 seasons. Injuries to the knee were the fifth most common cause of missed time in all of baseball, and the fourth most common reason for missed games in the MLB alone. Approximately 12% of all injuries required surgical intervention. The most common mechanism of injury was noncontact (44%), and base runners were injured more frequently than any other position (24%). The infield (30%) and home plate (23%) were the most common locations in which injuries occurred. These data can be utilized for targeted injury prevention initiatives.

RELATIONSHIP BETWEEN ISOKINETIC KNEE STRENGTH AND JUMP CHARACTERISTICS FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION.

BACKGROUND: Clinicians are often challenged when making return-to-play decisions following anterior cruciate ligament reconstruction (ACL-R). Isokinetic strength and jump performance testing are common tools used to make this decision. Unfortunately, vertical jump performance standards have not been clearly established and many clinicians do not have access to isokinetic testing equipment. PURPOSE: To establish normative jump and strength characteristics in ACL-R patients cleared by an orthopedic physician to return-to-play and to determine if relationships exist between knee isokinetic strength measurements and jump characteristics described using an electronic jump map system. STUDY DESIGN: Descriptive laboratory study. METHODS: Thirty-three ACL-R patients who had been cleared to return to athletic competition participated in this study. Twenty-six of these ACL-R participants were also matched to 26 asymptomatic athletes based on sex, limb, height, and mass to determine isokinetic strength and jump characteristic differences between groups. Jump tests consisted of single leg vertical, double leg vertical, and a 4-jump single leg vertical jump assessed using an electronic jump mat system. Independent t-tests were used to determine differences between groups and multiple regression analyses were used to identify any relationships between jump performance and knee strength (p<0.05). RESULTS: The ACL-R group had lower vertical jump capabilities and some bilateral knee strength deficiencies compared to the matched control group. The ACL-R group also showed several moderate-to-strong positive relationships for both knee extension and flexion strength with several jump performance characteristics, such as single and double leg vertical jump height. CONCLUSION: The current results indicate that ACL-R patients present with several knee strength and vertical jump differences compared to a matched control group at the time of return-to-play. Also, ACL-R patient's performance on an electronic jump mat system is strongly related to isokinetic knee strength measures. LEVEL OF EVIDENCE: 2b.

Upper extremity blood flow changes in professional baseball pitchers between two consecutive seasons.

BACKGROUND: Because of the tremendous forces produced and the repetitive nature of baseball, players have shown various shoulder adaptations in strength and range of motion. However, no research has identified whether alterations occur in the blood flow to the dominant arm among competitive baseball players. METHODS: Twenty professional baseball pitchers and 16 position players participated. Measurements were taken on day 1 of 2 consecutive spring training seasons. Diagnostic ultrasound was used to measure blood flow of the throwing arm brachial artery. These measurements were taken in a standing position with the test arm resting at the participant's side and again with the test arm in a provocative shoulder position. Separate 1-way analyses of variance were conducted to compare blood flow between seasons (P < .05). RESULTS: In a resting position, the blood flow of the pitchers did not change from 1 year to the next (P = .48). However, blood flow of the pitchers in the provocative position significantly decreased after the first year (P = .009). The position players did not have any significant changes in blood flow for either arm position (P > .11). CONCLUSIONS: In a provocative shoulder position, the blood flow of pitchers significantly decreased after 1 competitive baseball season. These results indicate that after a competitive season, the blood flow to the upper extremity of pitchers may be compromised.

Correlation of Shoulder and Elbow Kinetics With Ball Velocity in Collegiate Baseball Pitchers.

CONTEXT: Throwing a baseball is a dynamic and violent act that places large magnitudes of stress on the shoulder and elbow. Specific injuries at the elbow and glenohumeral joints have been linked to several kinetic variables throughout the throwing motion. However, very little research has directly examined the relationship between these kinetic variables and ball velocity. OBJECTIVE: To examine the correlation of peak ball velocity with elbow-valgus torque, shoulder external-rotation torque, and shoulder-distraction force in a group of collegiate baseball pitchers. DESIGN: Cross-sectional study. SETTING: Motion-analysis laboratory. PATIENTS OR OTHER PARTICIPANTS: Sixty-seven asymptomatic National Collegiate Athletic Association Division I baseball pitchers (age = 19.5 ± 1.2 years, height = 186.2 ± 5.7 cm, mass = 86.7 ± 7.0 kg; 48 right handed, 19 left handed). MAIN OUTCOME MEASURE(S): We measured peak ball velocity using a radar gun and shoulder and elbow kinetics of the throwing arm using 8 electronically synchronized, high-speed digital cameras. We placed 26 reflective markers on anatomical landmarks of each participant to track 3-dimensional coordinate data. The average data from the 3 highest-velocity fastballs thrown for strikes were used for data analysis. We calculated a Pearson correlation coefficient to determine the associations between ball velocity and peak elbow-valgus torque, shoulder-distraction force, and shoulder external-rotation torque (P < .05). RESULTS: A weak positive correlation was found between ball velocity and shoulder-distraction force (r = 0.257; 95% confidence interval [CI] = 0.02, 0.47; r(2) = 0.066; P = .018). However, no significant correlations were noted between ball velocity and elbow-valgus torque (r = 0.199; 95% CI = -0.043, 0.419; r(2) = 0.040; P = .053) or shoulder external-rotation torque (r = 0.097; 95% CI = -0.147, 0.329; r(2) = 0.009; P = .217). CONCLUSIONS: Although a weak positive correlation was present between ball velocity and shoulder-distraction force, no significant association was seen between ball velocity and elbow-valgus torque or shoulder external-rotation torque. Therefore, other factors, such as improper pitching mechanics, may contribute more to increases in joint kinetics than peak ball velocity.

The relationship between clinically measured hip rotational motion and shoulder biomechanics during the pitching motion.

OBJECTIVES: To examine how clinically measured hip motion is related to shoulder biomechanics during the pitching motion. DESIGN: Cross-sectional. METHODS: Bilateral hip rotational range of motion was measured clinically among 34 collegiate baseball pitchers. External rotation torque and maximum horizontal adduction range of motion of the throwing shoulder were measured using a three-dimensional, high speed video capture system. RESULTS: Separate standard multiple regression analyses showed that the total hip rotational range of motion of the lead leg had a significant relationship with shoulder external rotation torque during the throwing motion (r=0.56, P=0.003). Both lead leg hip external rotation range of motion (r=-0.39, P=0.02) and internal rotation range of motion (r=0.42, P=0.009) made significant contributions to this dependent variable. Lead leg external rotation range of motion also had a significant negative relationship with shoulder horizontal adduction range of motion (r=-0.36, P=0.04). The total rotational range of motion of the trail leg had a significant relationship with shoulder horizontal adduction range of motion (r=0.43, P=0.04). However, trail leg external rotation range of motion was the only significant contributor to this relationship (r=-0.35, P=0.04). No other significant relationships were noted (r<0.37, P>0.11). CONCLUSIONS: Our results demonstrate that altered hip rotational range of motion, measured clinically, has a direct effect on the amount of external rotation torque and horizontal adduction range of motion of the shoulder during the throwing motion.

Decreased blood flow in the throwing arm of professional baseball pitchers.

BACKGROUND: As a consequence of the repetitive forces placed on the throwing arm of a baseball player, various bony, capsuloligamentous, and muscular adaptations occur and have been identified. However, no research has identified whether adaptations also exist in the vasculature of the upper extremity in the competitive baseball player. METHODS: Fifty-one professional baseball pitchers and 34 position players participated. Diagnostic ultrasound was used to measure bilateral blood flow of the brachial artery. These measurements were taken with the participant standing with the test arm resting at the participant's side and again with the test arm in a provocative shoulder position. RESULTS: The throwing arm of the pitchers had significantly less blood flow volume when in the provocative shoulder position compared with their nonthrowing arm (P = .01). Pitchers did not have any bilateral difference while in the resting position (P = .19). There were no bilateral differences among the position players while in the resting (P = .64) or provocative positions (P = .63). Pitchers had significantly less blood flow of the throwing shoulder while in the provocative position compared with position players (P = .02). There were no other between-group differences. CONCLUSIONS: While in a provocative shoulder position, pitchers have significantly less blood flow in their throwing arm compared with their nonthrowing arm and with the throwing arm of position players. These results provide a descriptive profile of blood flow volume among baseball players, which may be used in the evaluation and treatment of such athletes with vascular disorders.

Thoracolumbar range of motion in baseball pitchers and position players.

INTRODUCTION/BACKGROUND: Optimal baseball throwing mechanics require a significant contribution of thoracolumbar motion, particularly in the sagittal and transverse planes. This motion is key for proper transmission of forces from the lower to upper extremity, thereby minimizing a throwing athlete's risk of injury and maximizing athletic performance. PURPOSE: To define the active-assisted thoracolumbar ROM of both baseball pitchers and position players and to compare these motions both within and between groups. METHODS: Fifty-six asymptomatic, collegiate and minor league baseball pitchers and 42 position players volunteered to participate. Active-assisted thoracolumbar flexion, extension, and bilateral rotation ROM, were measured in a standing position, using two bubble inclinometers. Two-tailed t tests were used to determine differences in ROM between and within the pitchers and position players. RESULTS: The pitchers had significantly more rotation to the non-throwing arm side as compared to the position players (p = .007, effect size = .61). The pitchers also had more rotation to the non-throwing arm side as compared to their throwing side (p = .006, effect size = .47). There were no other significant differences between the pitchers and the position players (p > .53). Furthermore, the position players did not have a side-to-side rotation difference (p = .99). CONCLUSIONS: Pitchers have a greater amount of rotation ROM towards the non-throwing arm side as compared to position players. Pitchers also have a greater amount of rotation ROM to the non-throwing arm side as compared to their throwing side rotation. Because pitchers often present with posterior shoulder tightness and subsequent altered shoulder horizontal adduction and internal rotation ROM, the increase in non-throwing side rotation ROM may occur in response to these adaptations. More specifically, this increase in non-throwing side trunk rotation ROM may allow such athletes to bring the arm across the body during the follow-through phase of the throwing motion despite posterior shoulder tightness. However, future research is necessary to investigate this relationship. Based on these results, clinicians should consider these thoracolumbar ROM adaptations in the prevention, evaluation, and treatment of baseball players. LEVEL OF EVIDENCE: 2b.

Shoulder adaptations among pitchers and position players over the course of a competitive baseball season.

OBJECTIVE: To determine if throwing arm shoulder range of motion (ROM) and scapular kinematic differences exist between baseball pitchers and position players over the course of a baseball season. DESIGN: Prospective cohort. SETTING: Professional baseball athletic training room. PARTICIPANTS: Sixteen asymptomatic professional baseball pitchers and 16 position players. INDEPENDENT VARIABLES: Preseason glenohumeral (GH) posterior tightness and scapular position. MAIN OUTCOME MEASURES: Throwing arm GH horizontal adduction ROM and GH internal rotation bilateral asymmetry ROM, as well as bilateral differences in forward scapular posture and throwing arm scapular upward rotation at rest, 60, 90, and 120 degrees of humeral elevation were measured. These measurements were taken before and at the conclusion of a 140-game baseball season. RESULTS: Analyses of covariances showed no significant differences in GH horizontal adduction or internal rotation asymmetry ROM between groups over the course of the season. However, the pitchers developed significantly less scapular upward rotation at 60 degrees (P = 0.007) and 90 degrees (P = 0.006) of humeral elevation compared with the position players during the season. Forward scapular posture (P = 0.23) and scapular upward rotation at 0 degrees (P = 0.93) and 120 degrees (P = 0.29) of humeral elevation were not significantly different between groups. CONCLUSIONS: These results suggest that baseball position players develop more scapular upward rotation over the course of a competitive season than pitchers. This discrepancy may increase the pitchers' risk of injury and may partially explain their higher incidence of shoulder injury compared with position players. Therefore, pitchers may benefit from strengthening exercises and stretches aimed at increasing scapular upward rotation throughout the competitive baseball season.

The relationship between anterior glenohumeral laxity and proprioception in collegiate baseball players.

OBJECTIVE: To determine if a relationship exists between anterior glenohumeral (GH) laxity and proprioception. DESIGN: Cross-sectional study. SETTING: University biomechanics laboratory. PARTICIPANTS: Thirty asymptomatic collegiate baseball players. INDEPENDENT VARIABLES: Anterior GH laxity. MAIN OUTCOME MEASURES: Proprioception (active joint position sense) at positions of 75 degrees of external rotation, 30 degrees of external rotation, and 30 degrees of internal rotation were measured using an isokinetic dynomometer. Anterior GH laxity was measured using an instrumented arthrometer. RESULTS: Linear regression analyses showed that there were no relationships between anterior GH laxity and active joint position sense at 30 degrees of GH internal rotation and 30 degrees of GH external rotation (r = 0.21, P = 0.13). However, there was a moderate positive relationship between anterior GH laxity and joint position sense at 75 degrees of shoulder external rotation (r = 0.56, P = 0.001). CONCLUSIONS: These results suggest that shoulder proprioception in 75 degrees of external rotation decreases as anterior GH laxity increases. These results may prove beneficial in the prevention, evaluation, and treatment of various shoulder injuries associated with GH laxity.