
==== Front
Int J Sports Phys Ther
Int J Sports Phys Ther
2159
International Journal of Sports Physical Therapy
2159-2896
NASMI Website: International Journal of Sports Physical Therapy

34123532
22532
10.26603/001c.22532
Original Research
Youth Baseball Caregiver Understanding of Safe Pitching Guidelines and Player Injury
Reintgen Christian MD 1
Zeppieri Jr Giorgio MPT 1
Bruner Michelle MS, ATC 1
Horodyski MaryBeth EdD 1
Waligora Andrew MD 1
Smith M Seth MD, PharmD 1
Farmer Kevin W MD 1
1 Department of Orthopaedic Surgery University of Florida https://ror.org/02y3ad647
Corresponding Author: Christian Reintgen reintcd@ortho.ufl.edu Department of Orthopaedic Surgery, University of Florida 3450 Hull Road, Gainesville, FL 32607 Fax: 3526274418
1 6 2021
2021
16 3 807815
8 9 2020
26 11 2020
© The Author(s)
https://creativecommons.org/licenses/by-nc-sa/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike License (4.0) which permits non-commercial use, distribution, and reproduction in any medium, provided the original author and source are credited. If you remix, transform, or build upon this work, you must distribute your contributions under the same license as the original.

Background

As more athletes participate in youth baseball, there has been an associated increase in upper extremity injuries. Knowledge of baseball injury prevention guidelines continues to be developed and defined as throwing-related injuries rise. The purpose of this study was to evaluate how knowledgeable youth baseball caregivers were about safe pitching guidelines and secondarily determine pitching practices which may be associated with increased risk of player injury.

Methods

A twenty-two question survey comprised of demographic data, knowledge of overhead throwing guidelines, pitching history, presence of risk factors associated with overhead throwing and pitching habits was distributed to the caregivers of youth baseball pitchers in North Central Florida.

Results

Eighty-three percent (81/98) of those polled were unaware of the existence of safe pitching guidelines, regardless of the pitcher’s playing experience (p > 0.05). Those who pitched more than six months out of the year were significantly more prone to experience throwing arm pain after a performance (p < 0.05). Fifty-two percent (51/98) of the caregivers recalled their child having throwing arm pain as a direct result of pitching, with twenty-six percent (25/98) of pitchers having to miss either a game or a pitching appearance. Twenty-seven percent (26/98) of all players went on to seek medical evaluation for arm discomfort due to pitching. Pitchers 13 years of age and older were more likely to throw curveballs and miss games because of throwing arm pain (p < 0.05).

Conclusion

Despite implementation and accessibility of safe pitching guidelines, a large portion of those surveyed were unaware or noncompliant with these established recommendations. Given the results of this study, further measures need to be taken to improve caregivers’ understanding of current guidelines to help increase compliance and protect youth pitchers.

Level of Evidence

Cross-sectional survey study, 3b

youth
overhead
injury
guidelines
baseball
==== Body
pmcINTRODUCTION

Analysis of how to improve the safety of all amateur sports participants is an area of interest for multiple groups including players, coaches, caregivers, and medical care providers. Protecting youth baseball players from preventable injuries is imperative considering there are over 200,000 youth baseball teams in the United States.1 Systems to reduce the incidence of overuse injuries include limiting pitch counts (during games, weeks, seasons), allowing for periods of time (months) without pitching, limiting participation in multiple leagues, regulating pitch type, and learning appropriate throwing mechanics.2–6 There are a number of sources that baseball players, caregivers, and coaches can use to learn about safe pitching practices, a majority of which can be found online (Table 1 and Table 2). Despite the accessibility of information regarding safe pitching practices, little league pitchers continue to experience overuse injuries.

57916 Table 1: MLB Pitch Smart Guidelines

Age	Daily Max
(Pitches in Game)	0 Days Rest	1 Days Rest	2 Days Rest	3 Days Rest	4 Days Rest	5 Days Rest	
7-8	50	1-20	21-35	36-50	N/A	N/A	N/A	
9-10	75	1-20	21-35	36-50	51-65	66+	N/A	
11-12	85	1-20	21-35	36-50	51-65	66+	N/A	
13-14	95	1-20	21-35	36-50	51-65	66+	N/A	
15-16	95	1-30	31-45	46-60	61-75	76+	N/A	
17-18	105	1-30	31-45	46-60	61-80	81+	N/A	
19﻿-﻿22	120	1-30	31-45	46-60	61-80	81-105	106+	

57917 Table 2: Youth baseball guideline resources

USA Baseball and Medical Safety Advisory Committee	http://web.usabaseball.com	
Little League Baseball	http://www.littleleague.org	
American Sports Medicine Institute	http://www.asmi.org	

A study performed by Fazarale et al. provided a questionnaire to youth baseball coaches in their region concerning the USA Baseball Medical and Safety Advisory Committee (USA BMSAC) pitching guidelines.3 Seventy-three percent of the coaches reported compliance with the recommendations, yet only 43% of the questions regarding pitch count and rest periods were answered correctly. The coaches surveyed believed that only 53% of other coaches in their league followed the guidelines. Furthermore, 19% of these coaches knew that at least one of their players pitched in a game with a sore or fatigued arm. This is of particular concern because many sports medicine experts see shoulder and elbow pain not as an innocent symptom, but rather a warning sign of an acute or developing overuse injury.1

Caregivers and youth baseball players often rely on coaches to enforce safe pitching practices, however previous data has demonstrated that this may not always be consistent.3,6 Petty et al. evaluated risk factors for ulnar collateral ligament (UCL) injury in high school pitchers. In their patient population only 13 of 25 pitchers (52%) believed their coaches were proactive about preventing throwing injuries. They also reported situations where they believed they were overthrowing, including pitching during playoff games, tournaments, and showcase tryouts.6 Additionally, youth pitchers themselves have demonstrated a substantial lack of comprehension of appropriate pitching practices, with as many as 85% reporting never having heard of USA BMSAC guidelines and 57% indicating that they would not seek medical help if they had throwing arm pain after a game.7

The failure of appropriate education can occur at many levels, including ignorance that guidelines exist, lack of awareness of where to learn about guidelines, inaccurate provision of information by coaches, and failure to understand the overall importance of guidelines. To date, no study has evaluated the knowledge that each child’s caregiver possesses. The primary purpose of this study was to evaluate how knowledgeable youth baseball caregivers were about safe pitching guidelines and secondarily determine pitching practices which may be associated with increased risk of player injury.

MATERIALS AND METHODS

This cross-sectional survey study was approved by the University of Florida Institutional Review Board. A twenty-two question survey was distributed to the caregivers of youth baseball pitchers between the ages of 7 and 18 years old across North Central Florida. Locations utilized for distribution included regional baseball fields during practices and games, the Orthopaedics and Sports Medicine Institute clinics, and affiliated physical therapy/rehabilitation centers in order to reduce bias. The survey was constructed to capture questions on caregiver demographic data, knowledge of throwing guidelines, athlete pitching background and throwing habits based on recommendations provided by the USA Baseball and Medical Safety Advisory Committee, Little League Baseball, and the American Sports Medicine Institute (Appendix 1). The caregivers of the youth pitchers were asked to complete and return the survey. The results of each survey were then placed into a deidentified database using the Research Electronic Data Capture (REDCap)8 application at the University of Florida. Chi-square analysis was used to evaluate the categorical variables with the level of significance set a-priori at p ≤ 0.05. As guidelines stratify recommendations based on specific age brackets, a separate subgroup analysis was performed between pitchers less than 13 years old and those 13 years or older to represent youth athletes and those in adolescence.9

RESULTS

Population Characteristics

The survey resulted in 102 responses, 98 of which were used for analysis. One survey was excluded because it pertained to a baseball player who was not a pitcher and three others were completed by someone who was not the child’s primary caregiver. Fifty-two percent (51/98) identified themselves as the child’s mother. Ninety-one percent (89/98) of the respondents were Caucasian, and forty percent (39/98) of respondents fell within the 41 to 50 year-old age group. Of those surveyed, thirty-eight percent (37/98) were the caregivers of a pitcher between the ages of 13 and 16. With regards to education, seventy-six percent (74/98) had an associate’s degree, bachelor’s degree, or advanced degree (Table 3).

57918 Table 3: Caregiver Demographics

Relationship to Pitcher	Frequency	
Father	41/﻿98 (41.8%)	
Mother	51/﻿98 (52%)	
Other*	6/﻿98 (6.1%)	
Caregiver’s Ethnicity		
African American	4/﻿97 (4.1%)	
Asian	1/﻿97 (1%)	
Caucasian	89/﻿97 (91.7%)	
Hispanic	3/﻿97 (3.1%)	
Caregiver’s Highest Education Completed		
Grade school	2/﻿96 (2.1%)	
High school or GED	20/﻿96 (20.8%)	
Associate/Vocational degree	30/﻿96 (31.3%)	
Bachelor's degree	26/﻿96 (27.1%)	
Advanced degree	18/﻿96 (18.8%)	
*indicates other caregiver such as grandparent, aunt, uncle serving as child’s primary guardian

Survey Results

Eighty-three percent (81/98) of those polled were unaware of the existence of safe pitching guidelines. Fifty-three percent (52/98) of the surveyed population did not actively participate in monitoring their child’s pitch count. Seventeen percent (17/98) of the caregivers were unaware of how many pitches their children throw in a typical game. In children 13 years and older, if their caregiver was aware of pitching guidelines, they were more likely to estimate their child threw less than 85 pitches per game (p < 0.05).

Forty-four percent (43/98) of the pitchers threw in more than one league at a time while eighteen percent (18/98) pitched at least nine months out of the year. Participation in extra showcase scenarios was reported by fifty-eight percent (57/98) of caregivers and twenty-eight percent (27/98) of the youth pitchers participated in four showcase camps or more annually (Table 4). When not pitching, eleven percent (11/98) of the population identified catcher, twenty-six percent (25/98) outfield, and sixty-one percent (60/98) infield as their child’s primary position.

57919 Table 4: Pitcher Demographics

Pitcher’s Age Group (years)	Frequency	
7 - 8	9/﻿97 (9.3%)	
9 - 10	24/﻿97 (24.7%)	
11 - 12	16/﻿97 (16.5%)	
13 - 16	37/﻿97 (38.1%)	
17 - 18	11/﻿97 (11.3%)	
Other competitive sport participation during baseball season?		
Yes	22/﻿95 (23.2%)	
No	73/﻿95 (76.8%)	
Other competitive sport participation outside of baseball season?		
Yes	38/﻿98 (38.8%)	
No	60/﻿98 (61.2%)	
Number of leagues participated in at once?		
1	55/﻿98 (56.1%)	
2	41/﻿98 (41.8%)	
3	2/﻿98 (2%)	
Number of annual showcases/camps		
None	41/﻿98 (41.8%)	
3 or less	30/﻿98 (30.6%)	
4 or more	27/﻿98 (27.6%)	

Seventeen percent (17/98) of the caregivers surveyed did not know what kinds of pitches their children throw. Thirty-four percent (34/98) only threw fastballs, change-ups and knuckle balls while fifty-one percent (50/98) also threw breaking pitches (Figure 1). Forty-two percent (41/98) of children were taught pitching technique by their coach, followed by twenty-seven percent (26/98) with a hired instructor, twenty-one percent (21/98) answering “other”, and twelve percent (12/98) taught by a caregiver (either the respondent or their spouse).

57921 Figure 1: Pitches Thrown

Fifty-two percent (51/98) of the caregivers recalled their child having upper extremity pain as a direct result of pitching, which was located twenty-three (45%) times in the shoulder and nine times in the elbow (18%) (Table 5).

57922 Table 5: Location of Reported Body Pain (n=51). Some respondents reported pain in multiple locations

Body Part	Frequency	
Elbow	9	
Lower Arm	1	
Scapula	2	
Upper Arm	3	
Shoulder	23	
Ribs	1	
Unspecified	18	

Twenty-six percent (25/98) of the pitchers had to miss either a game or a pitching appearance because of their throwing arm pain, and twenty-seven percent (26/98) experienced pain concerning enough to be evaluated by a medical professional (Table 6).

Those pitchers who threw breaking pitches or threw for more than six months out of the year were more likely to experience arm pain after a pitching performance (Figure 2a and Figure 2b, Figure 3; p < 0.05). There was also a general trend toward significance noted in regards to increasing number of months pitching out of the year and arm pain (p = 0.059).

Variable Correlations

Compared to pitchers younger than 13, players 13 years and older were more likely to throw curveballs (25% compared to 12%; p < 0.05). Additionally, children 13 years of age and older were more likely to miss games because of throwing arm pain (20% compared to 6%; p < 0.05).

Using the same age cutoff of 13 years, there was no statistically significance difference found between awareness of youth pitching guidelines, number of pitches typically thrown in a game, position when not pitching, and who keeps track of pitch count (p > 0.05).

DISCUSSION

Overhead throwing creates an environment of significant mechanical stress. During the pitching motion, the kinetic chain transfers energy from the lower extremity, through the trunk, and finally through the upper extremity. The shoulder and elbow are sensitive to biomechanical stress and prone to pathology because they are inherently less stable joints and near the end of the energy transfer. Individuals who are involved in repetitive events, like pitchers, can be disposed to anatomical and mechanical changes in the throwing arm commonly presenting as overuse injuries.1,10,11

Eighty-three percent of baseball caregivers were unaware of safe pitching guidelines. Given the potential catastrophic complications that can occur from overhead pitching at an early age, the medical community should continue to make data-driven recommendations to best prevent irreparable damage. Many researchers have recognized that prevention of acute and chronic injuries stems from a multidisciplinary approach that includes sports medicine providers, coaches, and caregivers.1,6,12 Limpisvasti et al. recommended that injury prevention in youth baseball begin as early as possible. This is particularly true for those who have the opportunity to play at higher levels, as many of the injuries sustained later in a players’ career are speculated to be the culmination of insults that began at a young age.1

The overall rate of baseball overuse injuries has been estimated at 5% in some studies, with an injury rate of 1.39 per 10,000 athlete-exposures (AEs) for the shoulder and 0.86 per 10,000 AEs for the elbow.13,14 In their patient population, Andrews et. al showed that pitchers sustain the majority of shoulder (39.6%) and elbow (56.9%) injuries which were most often caused by overuse. From this same study 10.8% of shoulder injuries and 3.6% of elbow injuries required surgery.14 In this population, 26% of the pitchers had to miss at least one game because of throwing arm pain, and 27% had pain severe enough to require an evaluation by a physician. This number remains unacceptably high and merits further investigation into the failure of preventative measures.

Olsen et al demonstrated that the amount of pitching is the strongest risk factor that correlates with shoulder and elbow pathology. They determined that throwing greater than 80 pitches per appearance and pitching competitively more than eight months per year increased the odds of an injury requiring surgery by 3.83 and 5.05, respectively.15 Despite no statistically significant difference between average number of pitches thrown during a game and throwing arm pain, these findings otherwise support this conclusion with players throwing for greater than six months associated with a significant increase of throwing arm pain. Promisingly, only eighteen percent of participants pitched during nine or more months out of the year. In addition, Zaremski and Farmer demonstrated a highly likelihood of UCL reconstruction in athletes playing in the Southeastern Conference (SEC) compared to more northern conferences. This parallels the playing environment of pitchers from this study as rosters in the SEC consisted of a greater number of players from southern states and were more likely to have grown-up playing baseball year-round.16

57923 Table 6: Prevalence of throwing arm pain in youth pitchers

	Yes	No	Don’t Know	
Has your child experienced arm pain in their throwing arm after a pitching performance?	51/﻿97 (52.6%)	40/﻿97 (41.2%)	6/﻿97 (6.2%)	
Has your child ever had to miss a game/practice due to throwing arm pain?	25/﻿96 (26%)	67/﻿96 (69.8%)	4/﻿96 (4.2%)	
Has your child ever been evaluated by medical personnel for arm pain?	26/﻿96 (27.1%)	68/﻿96 (70.8%)	2/﻿96 (2.1%)	

57924 Figure 2a: Number of subjects who experienced pain if they pitched less than 6 months out of the year.

57925 Figure 2b: Number of subjects who experienced pain if they pitched greater than 6 months out of the year.

57926 Figure 3: Incidence of arm pain if breaking pitches were thrown

There are recommendations to limit the number of different leagues, teams, and showcases in which pitchers participate based on outcomes reported in previous retrospective reviews.17 Seventy-seven percent of players did not participate in other sports beside baseball during the season and only thirty-nine percent did play another sport outside of the baseball season. Although a growing trend and widely prevalent, early specialization in sports has been demonstrated to lead to higher rates of injury, increased psychological stress and loss of interest in playing.18 In this sample population forty-four percent of those surveyed reported that their child pitched in more than one league concurrently. Furthermore, while fifty-eight percent of pitchers participated in at least one showcase camp annually, twenty-eight percent participated in four or more. In many circumstances, pitchers have different coaches for each team or showcase. This leads to a lack of continuity in regulating pitch counts and appropriate time off. These situations demonstrate the importance of caregivers becoming both knowledgeable and compliant with safe pitching practices, yet the findings from this study demonstrate that at least fifty-three percent of youth pitchers will not have appropriate oversight.

Overuse injuries of the shoulder and elbow can be exacerbated by other repetitive overhead activities outside of pitching. Data published in 2001 demonstrated that a pitcher who also plays catcher is 2.7 times more likely to sustain a serious throwing arm injury.19 Additionally, Fleisig and Andrews noted that the shoulder and elbow microtrauma created during pitching may not have adequate time to resolve when pitchers also play catcher.13 These studies in part form the basis of the recommendation that a pitcher should not also play catcher for their team. Encouragingly, in the population of this survey only eleven percent of the baseball players identified playing catcher as their primary position when not pitching and although sixty-one percent reported playing in the infield secondarily, separate analysis did not find a significant association between alternate field position and throwing arm pain.

The appropriate age at which pitchers should begin to throw specific pitches has gained increasing interest in the sports medicine and baseball communities. Current recommendations from the American Academy of Orthopedic Surgeons (AAOS) are that pitchers should refrain from throwing breaking pitches (curveballs and sliders) until they are skeletally mature. This suggestion is more stringent than previous guidelines which recommended that pitchers not throw breaking pitches until 14 years of age.6 An article published in AJSM in 2002 investigated if there was a correlation between breaking pitches and injury by prospectively following 476 youth pitchers between the ages of 9 and 14 for a baseball season. They found that the curveball was associated with a 52% increase in shoulder pain while the slider increased elbow pain by 86%.10 Although questioned by more recent literature which has failed to find an increase in shoulder and elbow forces after breaking pitches compared to other types, in this population of pitchers analysis demonstrated a statistically significant relationship between those players who threw breaking pitches and throwing arm pain (p < 0.05).20,21 Nonetheless, 24% of pitchers under 13 years of age were reported to throw curveballs, and 10% in this same age group threw sliders. This result demonstrates that pitchers continue to participate in activities that are contrary to established guidelines. The reason for this may be unfamiliarity with the recommendations from coaches and caregivers or lack of knowledge regarding the association between types of pitches and throwing arm pain.

There are several limitations to this study which encompass the same confounding factors of other cross-sectional surveys. First, a majority of the surveys were administered to caregivers during athletic competition, while only a small amount were provided in a physician’s office or in physical therapy. This may lead to a selection and convenience sample bias, and may not be representative of the population at large. Similarly, this analysis illustrates only a specific geographical region (North Central Florida); therefore, the experiences in this location may not be characteristic of the rest of the country but are likely generalizable to other warm climate areas. More surveys were distributed than the total response of 102, and the nonresponse group may have answered differently which would have altered the results.

Several of the questions in the survey also ask specific details regarding pitch counts and days between performances – the nature of these questions is highly susceptible to recall bias. Although edited and tailored to focus on issues surrounding pitching, the questions may have unintentionally lead individuals or been misinterpreted. Additionally, private pitching lessons were not analyzed, which could have a dramatic effect on overall pitching volume.

Further directions based on the results of this study would include distributing either the same or a similar survey to multiple geographic locations so that all the data could be compiled into one data set for further review. These findings demonstrate a need for better education of youth baseball caregivers. One method of improving their knowledge of guidelines and access to resources would be for healthcare providers to participate in community outreach programs. The efficacy of these outreach programs could be evaluated by prospectively collecting data on shoulder and elbow injuries before and after their implementation.

CONCLUSION

No other study to date has sought to determine caregivers’ knowledge of safe pitching practices. Despite the implementation and accessibility of safe pitching guidelines, a large portion of those surveyed were unaware of or noncompliant with these established recommendations. These findings demonstrated an increase of throwing arm pain in youth baseball players pitching more than six months out of the year, suggesting that annual limitations on pitching performances be considered. Players 13 years and older were more likely to use breaking pitches and miss games due to throwing arm pain, supporting current guidelines from the AAOS that pitchers refrain from throwing breaking pitches until reaching skeletal maturity. Given the results of this study, further measures need to be taken to improve caregivers’ understanding of the guidelines to help increase compliance and protect youth pitchers. Injury prevention should be a multidisciplinary approach that includes educating coaches, caregivers, and youth pitchers. Future directions may include establishing outreach programs for the youth baseball community.

Support/Conflicts of Interest

No sources of support or conflicts of interest to disclose

Supplementary Material

Appendix 1: Caregiver Questionnaire
==== Refs
Understanding shoulder and elbow injuries in baseball Journal of the American Academy of Orthopaedic Surgeons Limpisvasti Orr ElAttrache Neal S. Jobe Frank W. 3 2007
15 3 139 147 1067-151X 10.5435/00124635-200703000-00003 10.5435/00124635-200703000-00003 17341670
A biomechanical comparison of youth baseball pitches: Is the curveball potentially harmful? The American Journal of Sports Medicine Dun Shouchen Loftice Jeremy Fleisig Glenn S. Kingsley David Andrews James R. SAGE Publications 4 2008
36 4 686 692 0363-5465 10.1177/0363546507310074 10.1177/0363546507310074 18055920
Knowledge of and compliance with pitch count recommendations: A survey of youth baseball coaches Sports Health: A Multidisciplinary Approach Fazarale Joseph J. Magnussen Robert A. Pedroza Angela D. Kaeding Christopher C. SAGE Publications 6 2 2012
4 3 202 204 1941-7381 10.1177/1941738111435632 10.1177/1941738111435632 23016087
Prevention of elbow injuries in youth baseball pitchers Sports Health: A Multidisciplinary Approach Fleisig Glenn S. Andrews James R. SAGE Publications 8 2012
4 5 419 424 1941-7381 10.1177/1941738112454828 10.1177/1941738112454828 23016115
Effect of pitch type, pitch count, and pitching mechanics on risk of elbow and shoulder pain in youth baseball pitchers The American Journal of Sports Medicine Lyman Stephen Fleisig Glenn S. Andrews James R. Osinski E. David SAGE Publications 7 2002
30 4 463 468 0363-5465 10.1177/03635465020300040201 10.1177/03635465020300040201 12130397
Ulnar collateral ligament reconstruction in high school baseball players: Clinical results and injury risk factors The American Journal of Sports Medicine Petty Damon H. Andrews James R. Fleisig Glenn S. Cain E. Lyle SAGE Publications 7 2004
32 5 1158 1164 0363-5465 10.1177/0363546503262166 10.1177/0363546503262166 15262637
Knowledge of injury prevention and prevalence of risk factors for throwing injuries in a sample of youth baseball players Int J Sports Phys Ther Bohne C George S Z Zeppieri G, Jr. 2015
10 4 464 26345986
Research electronic data capture (REDCap)—A metadata-driven methodology and workflow process for providing translational research informatics support Journal of Biomedical Informatics Harris Paul A. Taylor Robert Thielke Robert Payne Jonathon Gonzalez Nathaniel Conde Jose G. 4 2009
42 2 377 381 1532-0464 10.1016/j.jbi.2008.08.010 10.1016/j.jbi.2008.08.010 18929686
Preseason shoulder range of motion screening as a predictor of injury among youth and adolescent baseball pitchers Journal of Shoulder and Elbow Surgery Shanley Ellen Kissenberth Micheal J. Thigpen Charles A. Bailey Lane B. Hawkins Richard J. Michener Lori A. Tokish John M. Rauh Mitchell J. 7 2015
24 7 1005 1013 1058-2746 10.1016/j.jse.2015.03.012 10.1016/j.jse.2015.03.012 25957112
The effect of pitching biomechanics on the upper extremity in youth and adolescent baseball pitchers The American Journal of Sports Medicine Davis J.T. Limpisvasti Orr Fluhme Derrick Mohr Karen J. Yocum Lewis A. ElAttrache Neal S. Jobe Frank W. SAGE Publications 28 7 2009
37 8 1484 1491 0363-5465 10.1177/0363546509340226 10.1177/0363546509340226
An electromyographic analysis of the upper extremity in pitching Journal of Shoulder and Elbow Surgery DiGiovine Nick M. Jobe Frank W. Pink Marilyn Perry Jacquelin 1 1992
1 1 15 25 1058-2746 10.1016/s1058-2746(09)80011-6 10.1016/s1058-2746(09)80011-6
Shoulder injuries in the skeletally immature baseball pitcher and recommendations for the prevention of injury PMR Zaremski J.L. Krabak B.J. 2012
4 7 509 516
Risk of serious injury for young baseball pitchers: A 10-year prospective study The American Journal of Sports Medicine Fleisig Glenn S. Andrews James R. Cutter Gary R. Weber Adam Loftice Jeremy McMichael Chris Hassell Nina Lyman Stephen SAGE Publications 2011
39 2 253 257 0363-5465 10.1177/0363546510384224 10.1177/0363546510384224 21098816
Epidemiology of shoulder and elbow injuries among United States high school baseball players: School years 2005-2006 through 2014-2015 The American Journal of Sports Medicine Saper Michael G. Pierpoint Lauren A. Liu Wei Comstock R. Dawn Polousky John D. Andrews James R. SAGE Publications 2018
46 1 37 43 0363-5465 10.1177/0363546517734172 10.1177/0363546517734172
Risk factors for shoulder and elbow injuries in adolescent baseball pitchers The American Journal of Sports Medicine Olsen Samuel J. Fleisig Glenn S. Dun Shouchen Loftice Jeremy Andrews James R. SAGE Publications 6 2006
34 6 905 912 0363-5465 10.1177/0363546505284188 10.1177/0363546505284188 16452269
Does geographic location matter on the prevalence of ulnar collateral ligament reconstruction in collegiate baseball pitchers? Orthop J Sports Med Zaremski J.L. Hordyski M. Donlan R.M.. 2015
2325967115616582 26740953
Pitching practices and self-reported injuries among youth baseball pitchers: A descriptive study Athletic Training & Sports Health Care Register-Mihalik Johna K. Oyama Sakiko Marshall Stephen W. Mueller Frederick O. 2012
4 1 11 20 1942-5864 10.3928/19425864-20110331-01 10.3928/19425864-20110331-01
Sports specialization in young athletes: Evidence-based recommendations Sports Health: A Multidisciplinary Approach Jayanthi Neeru Pinkham Courtney Dugas Lara Patrick Brittany LaBella Cynthia SAGE Publications 2013
5 3 251 257 1941-7381 10.1177/1941738112464626 10.1177/1941738112464626 24427397
Injuries in little league baseball from 1987 through 1996: Implications for prevention The Physician and Sportsmedicine Mueller Frederick O. Marshall Stephen W. Kirby Daniel P. 7 2001
29 7 41 48 0091-3847 10.3810/psm.2001.07.874 10.3810/psm.2001.07.874
Kinetic comparison among the fastball, curveball, change-up, and slider in collegiate baseball pitchers The American Journal of Sports Medicine Fleisig Glenn S. Kingsley David S. Loftice Jeremy W. Dinnen Kenneth P. Ranganathan Rajiv Dun Shouchen Escamilla Rafael F. Andrews James R. SAGE Publications 3 2006
34 3 423 430 0363-5465 10.1177/0363546505280431 10.1177/0363546505280431 16260466
A biomechanical comparison of the fastball and curveball in adolescent baseball pitchers The American Journal of Sports Medicine Nissen Carl W. Westwell Melany Õunpuu Sylvia Patel Mausam Solomito Matthew Tate Janet SAGE Publications 15 5 2009
37 8 1492 1498 0363-5465 10.1177/0363546509333264 10.1177/0363546509333264
