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Concept: Baseball


Abstract The purpose of this article was to examine the effect of equipment scaling, through the modification of tennis ball compression, on elite junior tennis players (aged 10 years) within a match-play context. The two types of ball compressions that were compared were the standard compression (the normal ball) and 75% compression (termed the modified ball). Ten boys and 10 girls participated in the study. Participants were stratified into pairs based on their Australian Age Ranking and gender. Each pair played two two-set matches: one match with standard compression balls and one match with modified balls. The characteristics of each match were analysed and compared. The results showed that the use of the modified ball increased rally speed, allowed players to strike the ball at a lower (more comfortable) height on their groundstrokes and increased the number of balls played at the net. Ball compression had no effect on the relative number of winners, forehands, backhands, first serves in and double faults. The results are discussed in relation to skill acquisition for skilled junior tennis players.

Concepts: Skill, Learning, Data compression, Baseball, Tennis, Dreyfus model of skill acquisition, Balls, Junior tennis


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


Baseball pitching imposes a dangerous valgus load on the elbow that puts the joint at severe risk for injury. The goal of this study was to develop a musculoskeletal modeling approach to enable evaluation of muscle-tendon contributions to mitigating elbow injury risk in pitching. We implemented a forward dynamic simulation framework that used a scaled biomechanical model to reproduce a pitching motion recorded from a high school pitcher. The medial elbow muscles generated substantial, protective, varus elbow moments in our simulations. For our subject, the triceps generated large varus moments at the time of peak valgus loading; varus moments generated by the flexor digitorum superficialis were larger, but occurred later in the motion. Increasing muscle-tendon force output, either by augmenting parameters associated with strength and power or by increasing activation levels, decreased the load on the ulnar collateral ligament. Published methods have not previously quantified the biomechanics of elbow muscles during pitching. This simulation study represents a critical advancement in the study of baseball pitching and highlights the utility of simulation techniques in the study of this difficult problem.

Concepts: Simulation, Baseball, Pitcher, Fastball, Catcher, Baseball positions, Tommy John surgery, Relief pitcher


The Oxford Nanopore MinION sequencer, currently in pre-release testing through the MinION Access Programme (MAP), promises long reads in real-time from a cheap, compact, USB device. Tools have been released to extract FASTA/Q from the MinION base calling output and to provide basic yield statistics. However, no single tool yet exists to provide comprehensive alignment-based quality control and error profile analysis - something that is extremely important given the speed with which the platform is evolving.

Concepts: DNA, Quality control, Data, Computer program, Baseball, Tool, Universal Serial Bus, Profiles


Tearing of the anterior capsule of the shoulder is a rare but debilitating injury for throwing athletes. However, there is very little in the literature to guide its diagnosis and treatment. In this case series, we outline our experience with anterior capsular tears of the shoulder in professional baseball players.

Concepts: Baseball, Major League Baseball, Minor league baseball, Nippon Professional Baseball, Israel Baseball League, Honkbal Hoofdklasse


Many studies explored closed kinetic chain shoulder exercises (CKCSEs) with a sling because they are safer and more effective than open chain exercises, especially in early stages of treatment. However, the application of CKCSE in youth baseball players has been rarely attempted, although teenage baseball players also experience shoulder pain.

Concepts: Baseball, Major League Baseball, Softball, Little League Baseball, Amateur baseball in the United States, Little League World Series


Type III (T-III) endoleaks following endovascular aneurysm repair (EVAR) remain a major concern. Our center experienced a recent concentration of T-III endoleaks requiring elective and emergency treatment and prompted our review of all EVAR implants over a 40-month period from April 2011 until August 2014. This report represents a single center experience with T-III endoleak management with analysis of factors leading to the T-III-related failure of EVAR.

Concepts: Management, Experience, Urgent care, Chord, Semitone, Failure mode and effects analysis, 2011, Baseball


Baseball players, specifically pitchers, with symptomatic neurovascular occlusion often initially complain of arm fatigue, loss of ball control, and velocity. As the compression continues complaints may manifest into dull pain, paresthesia, and decreased grip strength.

Concepts: Upper limb, Baseball, Pitcher, Catcher, Batting, Designated hitter, Baseball positions, Pinch hitter


Ulnar collateral ligament reconstruction (UCLR) has become a common procedure among Major League Baseball (MLB) pitchers. It is unclear if a limit on innings pitched after UCLR should be instituted to prevent revision UCLR.

Concepts: Texas, Baseball, Major League Baseball, World Series, National League, American League, Designated hitter, Christy Mathewson


The number of Major League Baseball (MLB) pitchers requiring ulnar collateral ligament (UCL) reconstructions is increasing. Recent literature has attempted to correlate specific stresses placed on the throwing arm to risk for UCL injury, with limited results.

Concepts: Baseball, Pitcher, Major League Baseball, World Series, National League, American League, St. Louis Cardinals, Designated hitter