Search Results

You are looking at 1 - 10 of 10 items for :

  • Author: James R. Andrews x
  • Sport and Exercise Science/Kinesiology x
Clear All Modify Search
Restricted access

David F. Stodden, Glenn S. Fleisig, Scott P. McLean and James R. Andrews

To reach the level of elite, most baseball pitchers need to consistently produce high ball velocity but avoid high joint loads at the shoulder and elbow that may lead to injury. This study examined the relationship between fastball velocity and variations in throwing mechanics within 19 baseball pitchers who were analyzed via 3-D high-speed motion analysis. Inclusion in the study required each one to demonstrate a variation in velocity of at least 1.8 m/s (range 1.8–3.5 m/s) during 6 to 10 fastball pitch trials. Three mixed model analyses were performed to assess the independent effects of 7 kinetic, 11 temporal, and 12 kinematic parameters on pitched ball velocity. Results indicated that elbow flexion torque, shoulder proximal force, and elbow proximal force were the only three kinetic parameters significantly associated with increased ball velocity. Two temporal parameters (increased time to max shoulder horizontal adduction and decreased time to max shoulder internal rotation) and three kinematic parameters (decreased shoulder horizontal adduction at foot contact, decreased shoulder abduction during acceleration, and increased trunk tilt forward at release) were significantly related to increased ball velocity. These results point to variations in an individual's throwing mechanics that relate to pitched ball velocity, and also suggest that pitchers should focus on consistent mechanics to produce consistently high fastball velocities. In addition, pitchers should strengthen shoulder and elbow musculature that resist distraction as well as improve trunk strength and flexibility to maximize pitching velocity and help prevent injury.

Restricted access

Tomoyuki Matsuo, Glenn S. Fleisig, Naiquan Zheng and James R. Andrews

Elbow varus torque is a primary factor in the risk of elbow injury during pitching. To examine the effects of shoulder abduction and lateral trunk tilt angles on elbow varus torque, we conducted simulation and regression analyses on 33 college baseball pitchers. Motion data were used for computer simulations in which two angles— shoulder abduction and lateral trunk tilt—were systematically altered. Forty-two simulated motions were generated for each pitcher, and the peak elbow varus torque for each simulated motion was calculated. A two-way analysis of variance was performed to analyze the effects of shoulder abduction and trunk tilt on elbow varus torque. Regression analyses of a simple regression model, second-order regression model, and multiple regression model were also performed. Although regression analyses did not show any significant relationship, computer simulation indicated that the peak elbow varus torque was affected by both angles, and the interaction of those angles was also significant. As trunk tilt to the contralateral side increased, the shoulder abduction angle producing the minimum peak elbow varus torque decreased. It is suggested that shoulder abduction and lateral trunk tilt may be only two of several determinants of peak elbow varus torque.

Restricted access

David F. Stodden, Glenn S. Fleisig, Scott P. McLean, Stephen L. Lyman and James R. Andrews

Generating consistent maximum ball velocity is an important factor for a baseball pitcher’s success. While previous investigations have focused on the role of the upper and lower extremities, little attention has been given to the trunk. In this study it was hypothesized that variations in pelvis and upper torso kinematics within individual pitchers would be significantly associated with variations in pitched ball velocity. Nineteen elite baseball pitchers were analyzed using 3-D high-speed motion analysis. For inclusion in this study, each pitcher demonstrated a variation in ball velocity of at least 1.8 m/s (range: 1.8–3.5 m/s) during his 10 fastball pitch trials. A mixed-model analysis was used to determine the relationship between 12 pelvis and upper torso kinematic variables and pitched ball velocity. Results indicated that five variables were associated with variations in ball velocity within individual pitchers: pelvis orientation at maximum external rotation of the throwing shoulder (p = .026), pelvis orientation at ball release (p = .044), upper torso orientation at maximum external rotation of the throwing shoulder (p = .007), average pelvis velocity during arm cocking (p = .024), and average upper torso velocity during arm acceleration (p = .035). As ball velocity increased, pitchers showed an increase in pelvis orientation and upper torso orientation at the instant of maximal external rotation of the throwing shoulder. In addition, average pelvis velocity during arm cocking and average upper torso velocity during arm acceleration increased as ball velocity increased. From a practical perspective, the athlete should be coached to strive for proper trunk rotation during arm cocking as well as strength and flexibility in order to generate angular velocity within the trunk for maximum ball velocity.

Restricted access

Rafael F. Escamilla, Glenn S. Fleisig, Steven W. Barrentine, Naiquan Zheng and James R. Andrews

The purpose of this study was to establish and compare kinematic data among four groups of collegiate pitchers who threw the fastball (FA), change-up (CH), curveball (CU), and slider (SL). Twenty-six kinematic parameters at lead foot contact, during the arm-cocking and arm acceleration phases, and at ball release were measured for 16 collegiate baseball pitchers. Approximately 60% of these parameters showed significant differences among the four pitch variations. The greatest number of differences (14 of 26) occurred between the FA and CH groups, while the fewest differences (2 of 26) occurred between the FA and SL groups. The CH group had the smallest knee and elbow flexion at lead foot contact and the greatest knee and elbow flexion at ball release. During the arm-cocking and arm acceleration phases, peak shoulder, elbow, and trunk angular velocities were generally greatest in the FA and SL groups and smallest in the CH group. At ball release the CH group had the most upright trunk and the greatest horizontal shoulder adduction, while the CU group had the most lateral trunk tilt. Understanding kinematic differences can help a pitcher select and learn different pitches and can help a batter learn how to identify different pitches.

Restricted access

Steven W. Barrentine, Tomoyuki Matsuo, Rafael F. Escamilla, Glenn S. Fleisig and James R. Andrews

Previous researchers studying baseball pitching have compared kinematic and kinetic parameters among different types of pitches, focusing on the trunk, shoulder, and elbow. The lack of data on the wrist and forearm limits the understanding of clinicians, coaches, and researchers regarding the mechanics of baseball pitching and the differences among types of pitches. The purpose of this study was to expand existing knowledge of baseball pitching by quantifying and comparing kinematic data of the wrist and forearm for the fastball (FA), curveball (CU) and change-up (CH) pitches. Kinematic and temporal parameters were determined from 8 collegiate pitchers recorded with a four-camera system (200 Hz). Although significant differences were observed for all pitch comparisons, the least number of differences occurred between the FA and CH. During arm cocking, peak wrist extension for the FA and CH pitches was greater than for the CU, while forearm supination was greater for the CU. In contrast to the current study, previous comparisons of kinematic data for trunk, shoulder, and elbow revealed similarities between the FA and CU pitches and differences between the FA and CH pitches. Kinematic differences among pitches depend on the segment of the body studied.

Restricted access

Tomoyuki Matsuo, Rafael F. Escamilla, Glenn S. Fleisig, Steven W. Barrentine and James R. Andrews

This study investigated differences in kinematic and temporal parameters between two velocity groups of baseball pitchers. Data were collected from 127 healthy college and professional baseball pitchers. Those who threw faster than 1 SD above the sample mean (>38.0 m/s) were assigned to the high velocity group (n = 29), and those who threw slower than 1 SD below the sample mean (<34.2 m/s) were assigned to the low velocity group (n = 23). Twelve kinematic parameters and 9 temporal parameters were measured and analyzed. The pattern of lead knee movement was also investigated. Maximum shoulder external rotation, forward trunk tilt at the instant of ball release, and lead knee extension angular velocity at the instant of ball release were significantly greater in the high velocity group. Maximum lead knee flexion angular velocity was significantly greater in the low velocity group. Seventy percent of the high velocity group showed knee extension during the approach to ball release, whereas the low velocity group showed a variety of knee movement patterns involving less knee extension and more knee flexion. The greater shoulder external rotation in the high velocity group produced an increased range of motion during the acceleration phase.

Restricted access

Glenn S. Fleisig, Rafael F. Escamilla, James R. Andrews, Tomoyuki Matsuo, Yvonne Satterwhite and Steve W. Barrentine

Kinematic and kinetic aspects of baseball pitching and football passing were compared. Twenty-six high school and collegiate pitchers and 26 high school and collegiate quarterbacks were analyzed using three-dimensional high-speed motion analysis. Although maximum shoulder external rotation occurred earlier for quarterbacks, maximum angular velocity of pelvis rotation, upper torso rotation, elbow extension, and shoulder internal rotation occurred earlier and achieved greater magnitude for pitchers. Quarterbacks had shorter strides and stood more erect at ball release. During arm cocking, quarterbacks demonstrated greater elbow flexion and shoulder horizontal adduction. To decelerate the arm, pitchers generated greater compressive force at the elbow and greater compressive force and adduction torque at the shoulder. These results may help explain differences in performance and injury rates between the two sports.

Restricted access

Yungchien Chu, Glenn S. Fleisig, Kathy J. Simpson and James R. Andrews

The purpose of the current study was to identify the biomechanical features of elite female baseball pitching. Kinematics and kinetics of eleven elite female baseball pitchers were reported and compared with eleven elite male pitchers. Results suggested that females share many similarities with males in pitching kinematics, with a few significant differences. Specifically, at the instant of stride foot contact, a female pitcher had a shorter and more open stride and less separation between pelvis orientation and upper torso orientation. From foot contact to ball release, a female pitcher produced lower peak angular velocity for throwing elbow extension and stride knee extension. Ball velocity was lower for the female. Foot contact to ball release took more time for a female pitcher. Maximal proximal forces at the shoulder and elbow joints were less for a female pitcher.

Restricted access

Rafael F. Escamilla, Glenn S. Fleisig, Coop DeRenne, Marcus K. Taylor, Claude T. Moorman III, Rodney Imamura, Edward Barakatt and James R. Andrews

A motion system collected 120-Hz data from 14 baseball adult hitters using normal and choke-up bat grips. Six swings were digitized for each hitter, and temporal and kinematic parameters were calculated. Compared with a normal grip, the choke-up grip resulted in 1) less time during stride phase and swing; 2) the upper torso more opened at lead foot contact; 3) the pelvis more closed and less bat linear velocity at bat-ball contact; 4) less range of motion of the upper torso and pelvis during swing; 5) greater elbow flexion at lead foot contact; and 6) greater peak right elbow extension angular velocity. The decreased time during the stride phase when using a choke-up grip implies that hitters quicken their stride when they choke up. Less swing time duration and less upper torso and pelvis rotation range of motion using the choke-up grip supports the belief of many coaches and players that using a choke-up grip results in a “quicker” swing. However, the belief that using a choke-up grip leads to a faster moving bat was not supported by the results of this study.

Restricted access

Rafael F. Escamilla, Glenn S. Fleisig, Coop DeRenne, Marcus K. Taylor, Claude T. Moorman III, Rodney Imamura, Edward Barakatt and James R. Andrews

We propose that learning proper hitting kinematics should be encouraged at a young age during youth baseball because this may help reinforce proper hitting kinematics as a player progresses to higher levels of baseball in their adult years. To enhance our understanding between youth and adult baseball hitting, kinematic and temporal analyses of baseball hitting were evaluated with a high-speed motion analysis system between 12 skilled youth and 12 skilled adult baseball players. There were only a small number of temporal differences between youth and adult hitters, with adult hitters taking significantly greater time than youth hitters during the stride phase and during the swing. Compared with youth hitters, adult hitters a) had significantly greater (p < .01) lead knee flexion when the hands started to move forward; b) flexed the lead knee over a greater range of motion during the transition phase (31° versus 13°); c) extended the lead knee over a greater range of motion during the bat acceleration phase (59° versus 32°); d) maintained a more open pelvis position at lead foot off ground; and e) maintained a more open upper torso position when the hands started to move forward and a more closed upper torso position at bat-ball contact. Moreover, adult hitters had greater peak upper torso angular velocity (857°/s versus 717°/s), peak left elbow extension angular velocity (752°/s versus 598°/s), peak left knee extension angular velocity (386°/s versus 303°/s), and bat linear velocity at bat-ball contact (30 m/s versus 25 m/s). The numerous differences in kinematic and temporal parameters between youth and adult hitters suggest that hitting mechanics are different between these two groups.