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The purpose of the present study is to demonstrate the correlation between the force applied to a ball and the joint motion of the hip, trunk, shoulder and elbow in adolescent baseball players. The subjects were 15 adolescent baseball players (13.7±0.8 yrs) and 15 college-age baseball players (22.1±1.5). Pitching motion images were captured by three high-speed cameras, and 3D analysis established by the direct leaner translation method was performed to obtain the angles and the angular velocity of each joint, as well as the acceleration of the wrist toward the target at ball release (Acc). In the adolescent players, a significant linear correlation was found between Acc and trunk rotation angle (r=-0.59), elbow extension angle (r=-0.75), shoulder internal rotation velocity (r=-0.76) and elbow extension velocity (r=-0.61). In the college-age players, a significant linear correlation was found between Acc and hip adduction velocity (r=-0.51) and elbow extension velocity (r=-0.61). The finding indicates that adolescent players may depend more on the upper extremity motion than the hip joint motion when pitching. Coaches and athletic trainers may need to focus on the hip joint motion in order to prevent pitching injuries among adolescent baseball players. [ABSTRACT FROM AUTHOR]

This study aimed to demonstrate each joint angle at the maximum external rotation of the shoulder complex during the throwing of adolescent baseball players. The subjects were 15 adolescent baseball players (13.7±0.8 yrs) and 15 collegiate baseball players (22.1±1.5yrs). Throwing motion images were captured by three high-speed cameras, and a 3D analysis established by the direct leaner translation method was performed to obtain the shoulder external rotation, the glenohumeral external rotation (ER), and scapular posterior tilt angles. In the adolescent baseball players, the mean (±SD) value of the maximum external rotation angle (MER) was 141 ±15°, whereas the mean values of the glenohumeral ER and the scapula posterior tilt angles at the MER were 109±15° and 31±14°. Conversely, each angle of the college baseball players was 144±11°, 107±15°, and 29±14° respectively. There were no differences between the adolescent players and the college players. The adolescent players may need the same shoulder joint angles as the college players [ABSTRACT FROM AUTHOR]

A high prevalence of anterior cruciate ligament (ACL) injury has been reported in judo. However, there has been very little research concerning events preceding the injury. Therefore, the objective of this study was to determine the common situations and mechanisms of ACL injury in judo. A total of 60 cases of ACL injuries that had occurred during judo competitions or practice were investigated through interview conducted by a single certified athletic trainer who has 20 years of judo experience. We then obtained information regarding the situation and mechanism in which the ACL injury occurred. The direct contact mechanism was observed more frequently than the other injury mechanisms in the ACL incidence in judo. In addition, the number of ACL injuries was significantly higher when the subject was attacked by the opponent than when counterattacked or when attempting to attack. In addition, osoto-gari was the leading technique that directly caused ACL injury incident among the subjects. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to demonstrate the correlation between MER during throwing and each range of motion (ROM) of the shoulder complex, which consist of external rotation of glenohumeral joint and posterior tipping of the scapula in baseball players. The subjects were 19 collegiate baseball players. A three-dimensional analysis was performed to obtain the MER. The ROM of the external rotation of the shoulder complex (ER-ROM), ROM of the external rotation of the glenohumeral joint (GHE), and ROM of the posterior tipping of the scapula (SPT) were also passively measured. The mean (± SD) value of the MER was 150 ± 10°. The mean (± SD) values of the ER-ROM, GHE, and SPT were 135 ± 12°, 89 &plumsn; 12°, and 32 &plumsn; 7° respectively. Significant linear correlations were found between SPT and MER (r = 0.48), ER-ROM (r = 0.65). No significant correlations were found between GHE and MER and ER-ROM. The finding may indicate the importance of scapula motion more than glenohumeral joint motion for MER and ROM of the shoulder complex. [ABSTRACT FROM AUTHOR]

This study analyzes motions of the lower extremities and upper extremities during pitching, presents information on the kinetic linkage for pitching motion, and discusses the cause of the throwing injuries. The subjects involved were five elite-level baseball pitchers who were right-handed and over-hand styled. Fifty fastball pitchings were analyzed through a 3-dimensional video system. Analysis was made of the adduction angle of the left hip, the direction angle of the femur and the velocity of the right hand. Fifteen pitchings of 2nd to 16th, in the first third, 15 pitches of 35 - the 49th, as a latter third, were compared with the reappearance of each movement. In Subjects A and B, the motion of the hip joint, the thigh, and the right hand, were similar in the two periods. In Subject E, the hip joint, the thigh motion and the right hand were different at the latter third from the first third. These results suggest that there is a relationship between each movement of the lower extremities and upper extremities. The purpose of pitching is to throw a faster ball toward a fixed target. It is supposed that the disorder of the lower extremities is corrected in the upper extremities, which may result in injuries. [ABSTRACT FROM AUTHOR]

Many studies have been conducted to identify the mechanism of non-contact anterior cruciate ligament (ACL) injury. It is currently accepted that ACL injuries occur during stopping, cutting, or jump-landing with slight knee flexion and knee valgus. A half of ACL deficient knees require surgical intervention. Although the surgical technique has been improved, and the outcome is reasonably successful, the prevention of ACL injuries is still a primary issue in the field of sports medicine. However, the incidence of ACL injury has not been successfully decreased yet. Therefore, we developed an ACL injury prevention program. The purpose of our study is to report the effect of the ACL injury prevention program during the last 12 month period. Our program requires only 10 minutes, whereas the programs reported previously require approximately 30 to 60 minutes. One hundred and seventy-one female basketball players from high schools participated in our study. Eighty-five were the exercise group and 86 were the control group. They were instructed to perform the exercise program before every regular practice session. The exercise program consists of strengthening, balance, and jump-landing exercises. The visual exercise instructions recorded on a compact disc were given to each high school. Every three months, the participants were questioned about their exercise attendances and injury profiles followed by physical fitness tests. Two ACL injuries occurred during the intervention period in the exercise group and 4 injuries occurred in the control groups. The incidence of ACL injury was found to be 0.039 per 1,000 practice hours in the exercise group and 0.081 in the control groups. Although a shorter time is required for our program, a greater effect on decreasing the ACL injury incidence was observed in our study compared with previous studies. This finding enhances the current knowledge of ACL injury prevention. [ABSTRACT FROM AUTHOR]

The purpose of this study was to identify risk factors for medial elbow pain in high school baseball players by comparing the passive range of motion (ROM) of shoulder external rotation and maximum external rotation angle (MER) during throwing. Twenty high school baseball players who had recent episodes of medial elbow pain (elbow-injured group) and another twenty baseball players who had never experienced medial elbow pain (control group) participated in this experiment. Throwing motion data was collected by two high-speed video cameras, and three-dimensional (3D) coordinates of the shoulder complex were established by the direct leaner translation method for the MER calculation. Passive ROM of the shoulder external rotation was also bilaterally measured. Finally, the ratio of the MER to the ROM of the shoulder external rotation, which is the proposed index that shows the magnitude of valgus force on the elbow, was computed. A Mann-Whitney U test was performed for comparison. Although the difference was not statistically significant, the greater MER were found in the elbow-injured group than in the control group. In addition, the ratio of the MER to the ROM was significantly greater in the elbow-injured group. Our findings indicate that relatively large MER when compared with ROM could be one of the risk factors for medial elbow pain in high school baseball players. The greater ratio of the MER to the ROM may be responsible for increasing elbow valgus stress during throwing. [ABSTRACT FROM AUTHOR]