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Concept: Baseball bat


Higuchi, T, Nagami, T, Mizuguchi, N, and Anderson, T. The acute and chronic effects of isometric contraction conditioning on baseball bat velocity. J Strength Cond Res 27(1): 216-222, 2013-The purpose of this study was to examine (a) the acute change in bat velocity (BV) following three types of warm-up procedures for baseball hitting (experiment 1), and (b) the effect of an 8-week training program of isometric contraction conditioning (ISO) on BV (experiment 2). In experiment 1, the BV of 24 collegiate baseball players was measured before and after one of the three warm-up procedures; five standard bat (mass = 850.5 g) dry swings (SBS), five weighted bat (mass = 850.5 g + 680.4 g) dry swings (WBS), and four sets of 5-second maximal voluntary isometric contractions mimicking the bat swing movement pattern (ISO). BV was measured just before ball-bat impact. Experiment 2 followed experiment 1 and used only the ISO warm-up. Twelve of the 24 subjects formed the experimental group and underwent an 8-week training program (3 days per week) of ISO training. Results of experiment 1 indicated (a) no significant change in post-SBS BV (-0.33 m·s), (b) a significant decrease in post-WBS BV (-0.89 m·s; p < 0.05), and (c) a significant increase in post-ISO BV (+0.39 m·s; p < 0.05). In experiment 2, there was a significant increase in baseline BV after the 8-week training period (30.21 ± 1.83 m·s to 31.15 ± 1.57 m·s). A comparison of BV before and after ISO warm-up revealed that change was significantly greater after the training period (100.17 ± 3.18% vs. 103.75 ± 1.91%). Our results suggest that warm-up with WBS does not increase BV and that using the ISO has both acute and chronic positive effects on BV as a warm-up procedure to improve BV.

Concepts: Exercise, Experiment, Strength training, Resistance training, Isometric exercise, Baseball, Physical strength, Baseball bat


Compared to regulation-weight baseballs, lightweight baseballs generate lower torque on the shoulder and elbow joints without altering the pitching movement and timing. This study investigates the throwing accuracy, throwing velocity, arm swing velocity, and maximum shoulder external rotation (MSER) of adolescent players after 10 weeks of pitching training with appropriate lightweight baseballs. We assigned 24 adolescent players to a lightweight baseball group (Group L) and a regulation-weight baseball group (Group R) based on their pre-training throwing velocity. Both groups received pitching training 3 times per week for 10 weeks with 4.4-oz and 5-oz baseballs. The players' throwing accuracy, throwing velocity, arm swing velocity, and MSER were measured from 10 maximum efforts throws using a regulation-weight baseball before and after undergoing the pitching training. The results showed that the players in Group L significantly increased their throwing velocity and arm swing velocity (p < .05) after 10 weeks of pitching training with 4.4-oz baseball, whereas Group R did not (p > .05). Furthermore, the percentage change in the throwing velocity and arm swing velocity of Group L was significantly superior to that of Group R (p <.05). Thus, we concluded that the 10 weeks of pitching training with an appropriate lightweight baseball substantially enhanced the arm swing velocity and throwing velocity of the adolescent baseball players. These findings suggest that using a lightweight baseball, which can reduce the risk of injury without altering pitching patterns, has positive training effects on players in the rapid physical growth and technique development stage.

Concepts: Measurement, Baseball, Pitcher, Fastball, Major League Baseball, Baseball bat, Baseball Rubbing Mud


Stress fractures of the first rib are uncommon, and few reports have described the occurrence of this injury in overhead-throwing athletes. Furthermore, although there have been a few reports of first rib stress fractures on the throwing side in baseball players, fractures on the nonthrowing side are very rare. Here, we report 2 cases of first rib stress fractures on the nonthrowing side related to swinging of a baseball bat. The cause of the fractures in the present cases may have been repetitive traction and shear force on the first rib resulting from muscle exertion while swinging a bat. Conservative treatment that considered the mechanism of stress fractures resulted in a symptom-free and complication-free return to baseball. The patient’s background should be considered for an accurate understanding of the injury mechanism, adequate conservative therapeutic plan, and a successful return to baseball.

Concepts: Present, Report, Force, Shear stress, Case, Baseball, Baseball bat