***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background Joint pain is thought to be an early sign of injury to a pitcher . Objective To evaluate the association between pitch counts , pitch types , and pitching mechanics and  shoulder and elbow pain in young pitchers . Study Design Prospect i ve cohort study . Methods Four hundred and seventy-six young ( ages 9 to 14 years ) baseball pitchers were followed for one season . Data were collected from pre- and postseason question naires , injury and performance interviews after each game , pitch count logs , and video analysis of pitching mechanics . Generalized estimating equations and logistic regression analysis were used . Results Half of the subjects experienced elbow or shoulder pain during the season . The curveball was associated with a 52 % increased risk of shoulder pain and the slider was associated with an 86 % increased risk of elbow pain . There was a significant association between the number of pitches thrown in a game and during the season and the rate of elbow pain and shoulder pain . Conclusions Pitchers in this age group should be caution ed about throwing breaking pitches ( curveballs and sliders ) because of the increased risk of elbow and shoulder pain . Limitations on pitches thrown in a game and in a season can also reduce the risk of pain . Further evaluation of pain and pitching mechanics is necessary INTRODUCTION A recent US Major League Baseball ( MLB ) rule change requires baseball pitchers to deliver pitches within 12 s. PURPOSE S To examine the effect of three between-pitch rest intervals on throwing performance during a simulated seven-inning game  and muscle damage during postgame recovery . DESIGN A r and omized counterbalanced study . METHODS Seven intercollegiate pitchers threw 15 pitches per inning for seven innings with rest interval trials of 8 , 12 , and 20 s between pitches and 5 min between innings . Pitchers threw aim ed fastballs at their best effort . Trials were separated by ≥2 wk . RESULTS Progressive decreases in pitching speed and accuracy below baseline ( first inning of 20-s trial ) occurred after fourth inning during the 8-s and 12-s trials , but not the 20-s trial . Plasma creatine kinase elevated 48 h later for the 8-s and 12-s trials ( + 105 % and + 75 % , P < 0.01 ) , but not the 20-s trial ( + 26 % , no significance ) . A transient interleukin (IL)-6 surges immediately after the game for the 8- and 12-s trials ( + 265 % , + 128 % , P < 0.01 ) above baseline . IL-6 reversed below the level of 20-s trial at 48 h after game , whereas IL-10 increased significantly above the level of 20-s trial . CONCLUSIONS Under the same pitching load , decreasing rest interval from 20 to 12 s or less results in an early-onset performance loss during a game and increases in muscle damage and inflammation for more than 2 d after a game . Our data do not favor the current rule change in concern of keeping musculoskeletal health of pitchers OBJECTIVE : To test the feasibility of creating a valid and reliable checklist with the following features : appropriate for assessing both r and omised and non-r and omised studies ; provision of both an overall score for study quality and a profile of scores not only for the quality of reporting , internal validity ( bias and confounding ) and power , but also for external validity . DESIGN : A pilot version was first developed , based on epidemiological principles , review s , and existing checklists for r and omised studies . Face and content validity were assessed by three experienced review ers and reliability was determined using two raters assessing 10 r and omised and 10 non-r and omised studies . Using different raters , the checklist was revised and tested for internal consistency ( Kuder-Richardson 20 ) , test-retest and inter-rater reliability ( Spearman correlation coefficient and sign rank test ; kappa statistics ) , criterion validity , and respondent burden . MAIN RESULTS : The performance of the checklist improved considerably after revision of a pilot version . The Quality Index had high internal consistency ( KR-20 : 0.89 ) as did the subscales apart from external validity ( KR-20 : 0.54 ) . Test-retest ( r 0.88 ) and inter-rater ( r 0.75 ) reliability of the Quality Index were good . Reliability of the subscales varied from good ( bias ) to poor ( external validity ) . The Quality Index correlated highly with an existing , established instrument for assessing r and omised studies ( r 0.90 ) . There was little difference between its performance with non-r and omised and with r and omised studies . Raters took about 20 minutes to assess each paper ( range 10 to 45 minutes ) . CONCLUSIONS : This study has shown that it is feasible to develop a checklist that can be used to assess the method ological quality not only of r and omised controlled trials but also non-r and omised studies . It has also shown that it is possible to produce a checklist that provides a profile of the paper , alerting review ers to its particular method ological strengths and weaknesses . Further work is required to improve the checklist and the training of raters in the assessment of external validity CONTEXT Fatigue could contribute to ankle-sprain injuries during sport , particularly for individuals with chronic ankle instability ( CAI ) . OBJECTIVE To examine whether adults with or without CAI develop fatigue at similar rates when performing ankle exercises at the same relative effort level and whether these groups differ in their subjective perceptions of fatigue . DESIGN Controlled laboratory study . SETTING Biomechanics research laboratory . PATIENTS OR OTHER PARTICIPANTS A total of 11 volunteers with CAI ( 1 man , 10 women ; age = 23.5 ± 3.0 years , height = 168.0 ± 11.2 cm , mass = 64.3 ± 13.5 kg ) were recruited for the unstable-ankle group , and 11 volunteers matched for age , height , mass , and sex ( 1 man , 10 women ; age = 24.1 ± 2.1 years , height = 169.5 ± 9.7 cm , mass = 62.3 ± 9.7 kg ) were recruited as control participants . INTERVENTION(S ) Localized muscle fatigue ( LMF ) was induced in the ankle of the dominant limb using a custom fatigue protocol . Plantar-flexion and dorsiflexion exertions were completed at a rate of 12 cycles per minute at isotonic loads equal to 70 % and 30 % , respectively , of individual maximal voluntary isometric strength . Intermittent measures of maximal voluntary isometric strength and ratings of perceived exertion ( RPEs ) were obtained . MAIN OUTCOME MEASURE(S ) We compared isometric-strength measures and RPE scores at each observation time ( prefatigue and at 4 , 8 , 12 , and 16 minutes into the fatigue protocol ) and the group correlations between changes in strength and changes in RPE scores . RESULTS Based on ankle-strength measures , the 2 test groups developed LMF at similar rates when exercising at equivalent levels of relative effort . The 2 groups also reported similar levels of discomfort as fatigue progressed . CONCLUSIONS The rate of LMF development at the ankle and the associated perception of fatigue did not differ between adults with or without CAI Abstract Freeston , J , Adams , R , Ferdin and s , RED , and Rooney , K. Indicators of throwing arm fatigue in elite adolescent male baseball players : A r and omized crossover trial . J Strength Cond Res 28(8 ) : 2115–2120 , 2014—Throwing carries an inherent risk of injury that worsens in the presence of arm fatigue . The purpose of this study was to identify markers that could facilitate the early detection of this type of fatigue , by comparing the response to bouts of throwing-specific and running-based exercise .  Thirteen elite junior male baseball players were tested twice , 7 days apart with a r and omized crossover design . They were assessed for shoulder proprioception , maximal throwing velocity , and throwing accuracy before and after a 10-minute bout of either throwing-specific ( THROW ) or general ( RUN ) exercise .  Maximal throwing velocity was reduced similarly after both THROW and RUN bouts ( −1.0 ± 0.4 vs. −0.6 ± 0.2 m·s−1 , respectively ; p ⩽ 0.05 ) ; however , accuracy was only reduced after THROW ( 7.6 ± 3.4 cm ; p ⩽ 0.05 ) . Arm soreness increased significantly more after THROW than RUN ( 3.5 ± 0.7 vs. 1.4 ± 0.5 km·h−1 , respectively ; p ⩽ 0.05 ) . Shoulder proprioception did not change after either exercise bout . The results suggest that throwing velocity is an indicator of general fatigue , whereas throwing accuracy and arm soreness are markers of arm fatigue . Shoulder proprioception does not seem to be a sensitive marker of either type of fatigue . Throwing velocity should be monitored to gauge overall fatigue levels , whereas accuracy and arm soreness should be closely monitored to gauge arm fatigue and throwing-induced injury risk Abstract Oliver , GD , Weimar , WH , and Henning , LE . Effects of a simulated game on muscle activation in youth baseball pitchers . J Strength Cond Res 30(2 ) : 415–420 , 2016—It is generally accepted that playing with fatigue is a primary predictor of injury in youth baseball because muscular fatigue is believed to alter mechanics during the arm cocking and acceleration phases . Therefore , the purpose of this study was to quantitatively describe gluteal and upper extremity muscle activations in youth baseball pitchers during a simulated game .  Twenty-three youth baseball players ( 11.2 ± 0.8 years ; 151.4 ± 8.7 cm ; 47.5 ± 10.8 kg ) participated . Data were collected through a Delsys Bagnoli–8-channel electromyography system . Single differential electrodes ( interelectrode distance : 10 mm ) were attached to the bilateral gluteus maximus and medius and throwing side latissimus dorsi , lower trapezius , and serratus anterior and upper trapezius . After warm-up , participants were instructed to throw r and omly provided game situations over a regulation distance ( 46 feet ; 14.02 meters ) to a catcher . Three , 4-seam fastballs for strikes , thrown in the first and last innings of the simulated game were selected for analysis . A multivariate analysis of variance revealed no statistically significant differences in muscle activity at the 3 phases of the throw , between first and last innings of the simulated game with an observed power of 0.274 ( phase 1 : foot contact to maximum shoulder external rotation ) , 0.297 ( phase 2 : maximum shoulder external rotation to ball release ) , and 0.226 ( phase 3 : ball release to maximum shoulder internal rotation ) . Examining muscle activations as a pitcher approaches fatigue provides information on how long a pitcher can perform before mechanical alterations occur . Although this study did not reveal significant changes , it did reiterate the fact that pitch counts may be working in possibly preventing a youth pitcher throwing to fatigue BACKGROUND Overexertion caused by increased pitch counts can evoke protective biomechanical responses signified by decreased ball velocity , such as reduced throwing arm kinematics and kinetics . Among skilled pitchers , overexertion may not always present ball velocity decrements , because compensatory throwing biomechanics aid in maintaining peak ball velocity although lowering physiologic stress . METHODS Nineteen pitchers ( collegiate and elite high school ) , r and omly crossed over to pitch two simulated games at ± 25 % of their desired stride length , were recorded by an eight-camera motion capture system ( 240 Hz ) integrated with two piezoelectric force plates ( 960 Hz ) and a professional model radar gun . HR , self-reported exertion scores , blood glucose and lactate , salivary biomarkers , peak linear h and and fastball velocities were examined . Repeated- measures ANOVA as well as independent and pairwise t-tests examined significant differences ( P ≤ 0.05 ) . RESULTS Shortened strides reduced mean pitching HR by 11.1 bpm ( P < 0.001 ) , improved recovery capacity by 5.76 % ( P = 0.012 ) , and lowered salivary cortisol from baseline ( P = 0.001 ) . Physiologic stress elevated with greater strides , because salivary alpha amylase was significantly elevated from baseline ( P = 0.011 ) with no improvements evidence d in pitching HR or recovery capacity . Linear h and and ball velocities remained equivalent between stride conditions . CONCLUSION Stride length can affect physical exertion without disrupting ball velocity , where shortening strides can plausibly respond to competitive exertion in baseball pitchers . Current pitch count st and ards and radar velocity accounts have not been proven efficacious in predicting exertion in professional and collegiate baseball , where biomechanical compensations arise to maintain ball velocity . In some instances , compensatory adaptations may be pathomechanic where future research identifying injurious movement patterns can advance injury prevention in professional baseball 
    Output:
    
Conclusions Findings show that a co-dependence between changes in kinematics and a decrease in performance , which stems from central and peripheral fatigue , is a contributing factor of injury in baseball pitchers .
A large percentage of baseball pitchers exhibit pain or soreness in either their elbow or shoulder , or both at some point in a season .
Initially , kinematic changes occur that could maintain performance , but may increase joint and tissue loading .
Performance decreased with elevated pitch counts and innings thrown , and pitching further into games or the season .