Imaging of physeal stress in the upper extremity
(Ab)normal redefined
Kraan, R.B.J.
Publication date
2020
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Citation for published version (APA):
Kraan, R. B. J. (2020). Imaging of physeal stress in the upper extremity: (Ab)normal
redefined.
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8
Incidence, prevalence, and risk factors for elbow
and shoulder overuse injuries in youth athletes:
a systematic review
Translational Sports Medicine 2019; 2: 186–195 DOI: 10.1002/tsm2.82 Rik B.J. Kraan Daniëlle de Nobel Denise Eygendaal Joost G. Daams P. Paul F.M. Kuijer Mario Maas
Abstract
Objectives
In order to create sport-specific preventive measures to enhance healthy sport participation in youth athletes, valid data on incidence, prevalence, and aetiology of overuse injuries have
to be identified. This systematic review aims to provide an update on incidence, prevalence
and risk factors for overuse injuries of the elbow and shoulder in youth athletes participating in overhead sports.
Methods
MEDLINE and EMBASE were searched from inception until January 19th, 2018 for studies that
reported incidence, prevalence or risk-factors for overuse injuries or pain of the elbow and shoulder in youth overhead athletes.
Results
In total 36 studies were included. Incidence rates of overuse injuries of the elbow and shoulder were highest in tennis, baseball and softball. Incidence and prevalence of elbow pain in baseball was 12-58% and 17-35% respectively. Incidence of shoulder pain was 8-32% for baseball, 47% for basketball, 63% for handball and 52% for volleyball. Prevalence of shoulder pain was 9-16% for baseball, 41% for basketball, 32-49% for handball and 40% for volleyball. Risk factors for pain were almost exclusively described for youth baseball players and included playing position, throwing technique, and intensity and duration of training.
Conclusions
Incidence and prevalence of overuse injuries and pain of the elbow and shoulder is high in youth overhead athletes. Interpretation is challenging as different definitions are used to report overuse injuries and pain. Risk factors in youth baseball are largely covered by preventive pitch-count restrictions, knowledge on risk-factors in other overhead sports is currently lacking.
Introduction
Overuse injuries in youth athletes are a growing concern as the majority of sports related injuries in youth athletes are related to repetitive and excessive stress on the growing musculoskeletal
system.1 Youth athletes are increasingly pushed to perform at the limits of their physical
capacities in year-round training regimes and are therefore prone to overuse injuries.2 They
should be protected as many are willing to continue to compete even with pain.3,4 The increasing
prevalence of overuse injuries combined with a growing numbers of youth sports participants
emphasize the urgency for guidelines on healthy sports participation.2,5
The immature skeletal system of youth athletes participating in overhead sports is vulnerable
to the excessive forces caused by the repetitive powerful overhead motion.6 Injuries of the elbow
and shoulder in youth athletes related to overhead sports include osteochondritis dissecans of the humeral capitellum, disturbance of the growth plates of the medial epicondyle, olecranon
and the proximal humerus.6
These overuse injuries often necessitate temporary reduction of sport activities.7 However,
regularly athletes maintain (slightly altered) training schedules, even despite pain, to enhance and
continue sport performance.8 Most injury surveillance studies report injuries if athletes reduce
the number of training sessions or matches or seek medical attention.8,9 Therefore, (minor)
physical symptoms due to overuse are often underreported and incidence and prevalence reported in studies focusing on overuse injuries may be underestimated. In addition, the use of different injury-reporting methods and definitions for overuse injuries provide significant
variances in incidence and prevalence of overuse injuries.8,9
To create sport-specific preventive measures to enhance healthy sport participation and avoid short and long term sequelae of overuse injuries, valid data on incidence, prevalence and
aetiology of injuries have to be identified.10 A systematic overview of these data for overuse
injuries of the elbow and shoulder in youth athletes is currently lacking. The purpose of this study is to systematically review the current literature on incidence, prevalence and risk factors for overuse injuries as well as for pain of the shoulder and elbow in youth overhead athletes.
Methods
The protocol of this systematic review was registered in PROSPERO [#CRD42018086534]. The review is conducted according to the Preferred Reporting Items for Systematic Reviews and
Meta-Analyses (the PRISMA statement).11
Search strategy
MEDLINE and EMBASE were searched for studies reporting incidence, prevalence and risk factors for sports related overuse injuries and pain of the elbow and shoulder in youth athletes
participating in overhead sports. The search was performed January 19th, 2018 without date, or
language restrictions. The search strategy was developed in collaboration with an experienced library database specialist (JD) using a validation set of 25 articles and can be found in appendix 1. The WHO-ICTRP (International Clinical Trails Registry Platform) search portal was used to identify potentially relevant trials. Cochrane CENTRAL was searched to decide if a systematic search of the Cochrane Library was necessary.
Study selection
All studies were first imported in Endnote (Clarivate Analytics, Philadelphia, USA) for deduplication. Thereafter, the remaining studies were imported into Covidence (Veritas Health Innovation, Melbourne, Australia). Two researchers (DN and RBK) screened the studies on title and abstract independently using the following eligibility criteria: study population (youth overhead athletes <18 years old, with pain or overuse injury of the elbow or shoulder related to sports), study design (prospective- or retrospective cohort studies, case-control studies or cross-sectional studies) and outcomes (incidence and prevalence of reported pain or overuse injuries or risk factors for obtaining pain or overuse injuries). Disagreement on eligibility was resolved by mutual agreement. No restrictions were used for language and publication date.
Full text of studies that met eligibility criteria was retrieved. If full text remained unavailable via the journal or after contacting the authors, studies were excluded. Articles not written in English, Dutch, French or German were also excluded. Each full text was screened by two researchers (DN and RBK) using the following additional inclusion criteria; 1) study population; if the study population included athletes >18 years, less than 10% of the included athletes were older than 18 years or data from athletes <18 years could be analysed separately, 2) outcomes; incidence, prevalence and/or risk factors were either available or calculation was possible using the published data. Joint agreement was established if authors disagreed on eligibility. Reference lists of the eligible articles were checked for any additional relevant articles.
Data extraction
Data of the included articles was collected independently by two researchers (RBK and DN) using a data collection form. In case of variation in the extracted data, the data was extracted again jointly. Extracted data included study information (author, year and country of publication, study design, period of measurement and data collection process), study population (sample size, mean age, sex, type and level of overhead sport and playing position, history of injury) and outcomes for pain and overuse injuries (used definition, anatomic location, sample size and mean age, cumulative exposure to overhead sports, incidence, prevalence and risk factors).
If possible, incidence rates, prevalence and odds ratios for risk factors were calculated if not provided in the article. Incidence rates were defined as the number of injuries per 10,000 athletic exposures (AE; defined as one athlete participating in one game or practice). If published data was insufficient to calculate incidence or prevalence, authors were contacted if any additional information existed.
Quality assessment
Quality of the individual studies was evaluated by two independent reviewers (RBK and DN)
using a tool adapted from Shamliyan et al.12 and customized by Kox et al.13 for a review on
incidence, prevalence and risk factors for overuse injuries of the wrist. Differences in scores given by the two independent reviewers were settled with joint agreement.
Results
The search strategy yielded 10,590 records. After deduplication 7,665 records were assessed for eligibility, resulting in the inclusion of 36 articles for data extraction and analysis (figure 1).
Records identified through database searching
(n = 10,590)
Records after duplicates removed (n = 7665)
Records screened
(n = 7665) Records excluded (n = 7214)
Full-text articles assessed for eligibility
(n = 451)
Full-text articles excluded (n = 415) Wrong study design (n=188)
Wrong outcomes (n=142) Wrong study population (n=65)
Other (n = 20) Studies included in
qualitative synthesis (n = 36) Figure 1. Flow chart of study inclusion
Study characteristics
Eight studies reported overuse injuries of the elbow and/or shoulder as outcome measure. These
studies were published between 1997 and 2017 in the USA14-16, Australia17, Norway18, Finland19,
the Netherlands20 and Luxembourg.21 Four studies collected data prospectively18-21, while the
other studies had a retrospective study design.14-17
Twenty-eight articles focused on pain of the elbow and/or shoulder related to overhead
sports, published between 1965 and 2017. The studies were conducted in the USA22-33,
Japan34-45, Norway46, Brazil47, Taiwan48 and the UK.49 Sixteen of the articles that reported pain
as outcome were cross-sectional studies22,24,26-29,31-33,35,40,41,43-45,47,48, nine articles collected data
prospectively23,25,30,34,36-38,46,49 and two studies had a retrospective design.39,42
Study population
Participants described in the 36 included studies were between 6 and 22 years old. Most studies only included participants <18 years old. In 6 studies less than 10% of the study population consisted of participants older than 18 years and these studies were therefore included. Characteristics of the studies can be found in appendices 3, 4 and 5.
In total, five studies that focused on overuse injuries described 1,030 participants (sample size range 49-428, median 201). Sixty-two percent of the described patients were female. Three
studies14-16 did not report sample size, but reported total athletic exposure per sport. The mean
age of the athletes in the individual studies focussing on overuse injuries ranged between 12 and 17 years old. In three studies age of the study population was not specified and described as ‘high school age’, implying age between 14 and 18 years old.
The studies that reported pain rates as outcome described 27,049 participants. The sample size of the studies ranged from 73 to 7,894 (median 348). In 14 studies sex of the participants was not described. In the other 14 studies 611 females in 15,005 participants were reported (4%). Twenty-one studies reported a mean age, ranging between 10 and 17 years old. In eight studies age was only reported as range for the total study population, varying between 6 and 17 years old.
Overuse injuries
The eight studies that reported overuse as outcome measure reported injuries in baseball14-16,
softball14,15, basketball15,17,19,21, handball18,21, volleyball15,21 and tennis.20 Three studies described
overuse injuries in more than one sport and three studies focused on elite athletes. Several definitions for overuse injuries were used. Three studies used “chronic/overuse” as definition
for overuse injury without further specification.14-17 The other definitions used were “injury with
a gradual onset without any known trauma”18 and “micro trauma caused by chronic overload,
without a single, identifiable cause”.19,21 Van der Sluis et al. reported overuse injuries in tennis
players if any difficulties in sports-participation, reduction of training volume, effect on
Eight studies reported overuse injuries for the elbow and shoulder separately. One study did not distinguish between shoulder and elbow and reported overuse injuries of the upper extremity excluding the hand and wrist. Five studies described the incidence of overuse injuries as the amount of injuries per 10,000 or 1000 AE (-hours). Two studies provided incidence rates as amount of injuries per person per year/season and in one study the incidence had to be calculated with the provided data. Quality assessment showed that four studies were of sufficient quality and four studies were of good quality (appendix 6). An overview of incidence rates of overuse injuries in the different sports can be found in figure 2. Highest incidence rates of
overuse injuries of the elbow were found in tennis (2.65 per 10,000 AE)20 and baseball (0.29-0.35
per 10,000 AE).15,16 Incidence rates of overuse injuries of the shoulder were highest in tennis (5.30
per 10,000 AE)20, baseball (0.51-0.64 per 10,000 AE)15,16 and volleyball (0.38 per 10,000 AE).15
Baseball
Basketball
Baseball
Basketball
Handball
Softball
Tennis
Volleyball
Handball
Softball
Tennis
Volleyball
Shoulder Shoulder Elbow Elbow Elbow Elbow Elbow Elbow Shoulder Shoulder Shoulder Shoulder 2 0 0 2 4 6Overuse injuries per 10,000 AE or per year/season
Size of study 0 25 50 75 100 Metric Incidence per 10,000 AE Incidence per year/season Figure 2. Incidence of overuse injuries of the elbow and shoulder in six overhead sports. Incidence is
depicted as amount of injuries per 10,000 AE (in red) or amount of injuries per athlete per year/season (in blue). The size of the points represents the number of participants in the included study.
Pain
Twenty-five of the 28 studies that reported pain as outcome focussed on youth baseball
players.22-30,32-45,48,49 The three other studies described pain rates for handball46, volleyball31 or
handball, volleyball and basketball.47 Most studies used a binary scale to evaluate the presence
of elbow or shoulder. Three studies only reported pain if it was present for >1 week39 or >2
weeks38 and/or if it resulted in participation restriction of ≥1 day38,43. Incidence of pain was either
reported as incidence during one-season, during preseason24, during half a year28, during a 5
month period25 or during 30 days32. One study described consequence of pain (playing without
pain, playing with pain or not playing due to pain)23 and one study specified frequency of pain
(never, rarely, sometimes, often or always)28. Quality assessment showed that 9 studies were low
in quality, 12 studies were of sufficient quality and 7 studies were of good quality (appendix 6).
Handball Volleyball Basketball Baseball Baseball Baseball Baseball Shoulder pain Shoulder pain Shoulder pain Shoulder pain Elbow pain
Shoulder h/o pain Elbow h/o pain
80 60 40 20 0 0 20 40 60 80
Incidence or prevalence in %
Size of study 2000 4000 6000 Metric Incidence (%) Prevalence (%) History of pain (%) Figure 3. Incidence, prevalence and history of pain of the elbow and shoulder in several overhead sports.
Incidence (in red), prevalence (in blue) and history of pain (in green) are depicted as percentage of the total study population. The size of the points represents the number of participants in the included study.
An overview of incidence and prevalence data is reported in figure 3. Incidence and prevalence of elbow pain has only been described in baseball players and was 12-58%25,30,38,39,42,43,48,49 and 17-45%22,24,25,35,44, respectively. Seventeen to 63%26,34,35,40,41,44 of youth
baseball players reported a history of pain in the elbow. Incidence of shoulder pain was highest
among handball- (63%)47 and volleyball players (52%).47 Highest prevalence of shoulder pain
has been described in handball (32-49%)46,47, basketball (41%)47 and volleyball (40%).47
Several studies reported pain incidence and prevalence rates in youth baseball players for the upper extremity and did not distinguish between the shoulder and the elbow. The reported
incidence rates in these studies were 37% per season and 19% per 30 days.32,37 Prevalence
ranged between 11 and 41%.23,28,38 Two studies reported frequency of arm pain: one reported
incidence of arm pain while throwing during one season (34% sometimes, 4% often)29, the other
asked players if they had arm pain while throwing (30% sometimes, 0% often and 0% always)
and the day after throwing (31% sometimes, 11% often and 1% always).28
Risk factors
Twelve studies reported odds ratios (OR) for univariate analysis of risk factors for pain of the
elbow or shoulder related to baseball.24,28,29,31,32,34,36,39,40,42,43,45,49 One study reported risk factors
for overuse injuries in baseball players and one study reported risk factors for shoulder pain in
volleyball.16 Two studies were of good quality, three of sufficient quality and nine of low quality
(appendix 7). The individual risk factors described in the two studies of good quality are depicted in figure 4. An overview of all risk factors can be found in appendix 2.
Non modifiable risk-factors for elbow pain included older age and increased years of
baseball experience. In addition, youth baseball players with imaging abnormalities of the medial epicondyle or with capitellar osteochondritis dissecans were more likely to report elbow pain.
Modifiable risk factors for elbow pain in youth baseball players were increased body weight,
playing position, amount of training hours per week, and the amount of pitched games per year. Youth baseball players that had pitched 300-599 cumulative pitches during a season were less likely to report pain during a game compared to players that had thrown less than 300 pitches during the season. If the amount of cumulative pitches during the season exceeded 600 no significant differences were found in risk for elbow pain in the upcoming game. Multivariate analysis identified four additional risk factors for elbow pain in youth baseball players; smaller body-height, performing additional training (weightlifting and playing baseball outside the league), presence of arm fatigue and decreased self-satisfaction of performance.
Non-modifiable risk factors for shoulder pain were increased age, history of shoulder or
elbow pain and increased number of years of baseball experience. Reported modifiable risk factors included playing position (pitcher, catcher and infielder), amount of training hours per week, the number of in-game pitches and the amount of pitched innings per game. The risk of shoulder pain decreased for every 10 innings and each additional game that was pitched during the season. Youth baseball players that had thrown 300-599 cumulative pitches during the season were less likely to report pain during the next game compared to players that had thrown less than 300 pitches. Multivariate analysis showed the same difference for players that
had thrown more than 600 pitches and also showed that presence of arm fatigue and decreased self-satisfaction of performance was a risk factor for shoulder pain in youth baseball players.
300-599 pitches in-season >75 in-game pitches 50-74 in-game pitches Number of in-game pitches
Pitched games per season Pitched innings per game Pitched innings per season
Training 16-36 h/week History of elbow pain History of shoulder pain
Pitcher Catcher Infielder 3.5-4.5 y of baseball exp. 4.5-6 y of baseball exp. Age 9 years Age 10 years Age 11 years <300 pitches 1-24 in-game pitches 1-24 in-game pitches per 10 additional pitches
per additional game per additional inning per 10 additional innings
<10.5 h/week History of elbow pain History of shoulder pain
Outfielder Outfielder Outfielder <1.5 years <1.5 years Age <8 years Age <8 years Age <8 years 18 16 14 12 10 8 6 4 2 1 0 0 1 2 4 6 8 10 12 14 16 18 20 Odds Ratio
Anatomic Location Shoulder Elbow
Figure 4. Odds ratios of risk factors mentioned by the two studies with good study quality for overuse
related pain of the elbow (in blue) and shoulder (in red). The risk factors are colored by category (age, experience, playing position, history of pain and training/playing intensity). The size of the points represents the number of participants in the study and the whiskers illustrate the confidence interval.
Five studies did not specify between the elbow and shoulder and reported risk factors for arm pain. These risk factors were male sex, prior overuse injury or pitching related injury,
playing position, throwing curveballs and practicing more than 3 hours per day in weekends or practicing less than 3 hours per day on weekdays. Additional risk factors were pitching for multiple teams with overlapping seasons, pitching on consecutive days, or in multiple games a day and the amount of pitches in which the baseball players used 100% of their energy. Multivariate analysis showed that increased body-height was a risk factor for arm pain.
One study focused on overuse injuries of the shoulder and elbow and reported that pitchers were at risk. The study that focused on non-traumatic shoulder pain in volleyball players reported the amount of ball-contacts per week, weightlifting out of season and years of playing as risk factors.
Discussion
Results of this systematic review illustrate that incidence of overuse injuries in the elbow in youth overhead athletes was highest in baseball and tennis players and highest incidence of overuse injuries in the shoulder was seen in tennis, baseball and volleyball players. Incidence and prevalence of elbow pain in youth overhead athletes has only been described in baseball players and shoulder pain related to overhead sports is most often reported among handball, volleyball and basketball players.
Risk factors for shoulder and elbow pain are almost exclusively reported in baseball players. Modifiable risk factors included playing position, technique of throwing, and risk factors related to the intensity and amount of training and pitching.
Incidence and prevalence
A large variation was found between incidence and prevalence of overuse injuries and pain between different sports, especially the incidence of overuse injuries in tennis is high compared to the other sports. In addition, a wide range was reported in incidence and prevalence of overuse injuries and pain between different studies that focused on the same sport. Kox et al. described a similar variation in a review focused on incidence of overuse injuries in gymnastics
(0.02-26%).13
A few factors may contribute to the high incidence of overuse injuries in tennis. Single-sport specialization, which is a risk factor for obtaining overuse injuries, is more common in youth
tennis compared to other overhead sports.5,50 In addition, serve speed in tennis is constantly
increasing causing intensified strain on the elbow and shoulder.51 A major part of the difference
of incidence of overuse injuries in tennis compared to the other sports can however be attributed to a difference in the definition used for an overuse injury in the different studies.
The definition used for describing overuse injuries influences the reported incidence.8,9
Especially in studies that focus on overuse injuries, a uniform definition is essential as symptoms
related to overuse mainly appear gradually and often are transient in nature. Therefore, athletes
regularly continue training despite symptoms related to overuse.8,9 As a result these symptoms
will either be recorded or missed based on the definition used by the specific study. Clarsen et
al.8 demonstrated that an almost tenfold increase of overuse injuries was recorded in the same
population when a new standardized definition was used which is independent of time-loss
(Oslo Sports Trauma Research Centre overuse injury questionnaire).8
The study that reported overuse injury incidence in tennis by Van der Sluis et al.20 reported
injuries if symptoms related to overuse were present, while the other studies in this review reported injuries only if athletes missed a match or training. These differences are present in studies that reported incidence and prevalence of pain as well; some studies registered pain only if the athlete was absent for a match or training.
Furthermore, this review demonstrates substantial differences between pain and overuse injury rates in studies that focused on the same sport. Again, these differences can be attributed to the variation in definitions used for reporting overuse injuries and pain. For example, the studies used periods ranging between 30 days and one season to evaluate incidence of pain, resulting in a higher incidence of pain in the studies that used a longer period.
As a result of these differences in definitions, interpretation of incidence and prevalence of overuse problems in youth athletes is challenging. In addition, many athletes consider pain not as overuse problem but as part of the game and compete while having pain or while using
medication.3,4 The importance of identifying and protecting these athletes that have overuse
related pain is underlined by several studies demonstrating imaging abnormalities in a significant
amount of uninjured youth athletes.30,35,40,41
Risk factors
The ‘sequence of injury prevention’ as described by van Mechelen et al. consists of a 4-step
strategy.10 The first steps are to establish epidemiological data and information on aetiology,
injury mechanism and risk factors. Afterwards preventive measures can be introduced and their
effectiveness evaluated.10 In several sports (e.g. tennis and volleyball) injury prevention programs
have been developed and introduced that focus on adult athletes.52,53
In baseball preventive measures that focus on youth athletes are already successfully implemented for upper extremity injury prevention. These guidelines were introduced in 2007 and outline the number of pitches a youth pitcher is allowed to throw during a game
and how many days of rest are required after a certain number of pitches.30 Erickson et al.
evaluated the effectiveness of the age-related pitch-count restrictions; risk to require surgery for ulnar collateral ligament reconstruction is increased if athletes are not compliant to the pitch
restriction.54
In this review several modifiable risk factors are identified, e.g. number of pitches per game, pitching on consecutive days and pitching for multiple teams with overlapping seasons.
Identified risk factors are similar to the risk factors for obtaining shoulder and elbow injuries (not
limited to overuse injuries) in youth baseball reported in a recent systematic review.55 These risk
factors are largely covered by the preventive age-related pitch restrictions for youth baseball
players.30,56
More recent additional guidelines (‘Pitch Smart’) were published for the prevention of overuse injuries in youth baseball players. The additional recommendations included avoiding
of year-round playing and sport-specialization.30 The essence of preventive guidelines for
youth baseball players is underlined by a recent study of Pytiak et al.30; new or worse MRI
abnormalities were present in 8 of the 16 youth baseball players that underwent pre- and post-season MRI scans of the elbow. These players were 100% compliant to the age related
pitch-count restrictions, but showed low compliance to the additional Pitch Smart guidelines.30
In addition to the risk factors covered by the current preventive guidelines, this review illustrates a few non-modifiable risk-factors for pain in youth baseball players. These risk factors (for example age, injury history and years of baseball experience) should help coaches and (team) physicians in guiding individual athletes in order to prevent overuse injuries.
Beside risk factors for pain and overuse injuries in baseball players, this review identified a few risk-factors for non-traumatic shoulder pain in youth volleyball players. As one of the risk factors was the amount of ball contacts per week, preventive guidelines similar to the pitch-count restrictions (for example a smash-pitch-count restriction) could be a valuable addition to the
current preventive programs such as the ‘VolleyVeilig’ warmup program.52
Risk factors for elbow or shoulder injuries in youth athletes participating in other overhead sports are lacking, however the incidence and prevalence of pain and overuse injuries depicted by this review illustrate the urge to develop injury prevention programs focused on youth athletes in for example tennis and handball as well. Further research should therefore identify risk factors in these sports to evaluate the possibilities for preventive strategies.
Strengths and limitations
We applied several methods in order to optimize the overall quality of this literature review. An extensive and broad search strategy was developed in collaboration with an experienced library database specialist. In addition, two authors independently selected eligible articles based on the inclusion criteria and the PRISMA statement was used as guidance for items that should be
included in the systematic review 11. While extracting data and interpreting the results, we took
into account the quality of each study, based on a quality assessment using a previously used checklist. This systematic review also has limitations; despite the broad search strategy only few articles per sport were included that identified few overuse injuries. Many articles were excluded on full text if no clear distinction was made between traumatic and overuse injuries. The exclusion of these articles was necessary to answer our research questions, however this may limit representability and therefore conclusions based on these results have to be interpreted
carefully. In addition, especially in the articles that reported risk factors, methodological quality was moderate.
Perspectives
This review shows that overuse injuries and pain in the elbow and shoulder are prevalent among youth overhead athletes. Interpretation is challenging as several definitions are used for reporting overuse injuries and pain, emphasizing the need for uniform reporting guidelines.
Strategies for preventing overuse injuries of the elbow and shoulder are absent in most overhead sports, probably due to the lack of knowledge regarding risk-factors. Future research should focus on the identification of these risk factors to create dedicated preventive programs. However, in youth baseball extensive pitching guidelines are present and despite the proven
value implementation of these pitch-count restrictions is poor.57,58 Therefore, after identifying
the aforementioned risk factors, preventive measures should be developed in collaboration with coaches, athletes, parents, and (team-)physicians to optimize effectiveness, implementation and feasibility.
Finally, youth athletes and professionals surrounding them should be aware of the high risk for overuse injuries. If sport-specific preventive guidelines exist, adherence should be encouraged by federations through introducing either financial consequences or suspensions for coaches or teams if preventive measures are not followed. In the future, new technologies (e.g. a shirt for automatic pitch-count registration) should be explored to enhance feasibility of adherence to preventive guidelines.
Appendix 1. Full search strategy Ovid MEDLINE
1 exp racquet sport/ or volleyball/ or basketball/ or swimming/
2 (handball or basketball or baseball or swimming or racquet sport? or tennis or volleyball or cricket or javelin).ab,kf,ti. 3 or/1-2 [rel. sports]
4 prevention control.fs. or prevent*.ab,kf,ti. 5
(Manage training programs or (training adj3 (duration or intensity or recovery)) or (match adj5 frequen*) or season duration or Symptom monitoring system or medical help or Intensity monitoring or pitch velocity or Throwing technique or curveballs or Preseason supraspinatus strengthening or Dedicated warm-ups or Pitch-count or rest period).ab,kf,ti.
6 or/4-5 [prevention]
7 (injur* adj15 (handball or basketball or baseball or swimming or racquet sport? or tennis or volleyball or cricket or javelin)).ab,kf,ti. 8 injur*.hw.
9 (handball or basketball or baseball or swimming or racquet sport? or tennis or volleyball or cricket or javelin).ab,kf,ti. 10 8 and 9
11 or/7,10 [rel. sport injuries]
12 shoulder pain/ or exp cumulative trauma disorders/ or fractures, stress/
13 (shoulder pain or (shoulder? adj5 (complaint? or disorder? or extertion or flexion or repetitive)) or rotator cuff syndrome or cumulative trauma disorder? or little league or humeral epiphysi* or apophysi* or capitellum or capitellar or stress fracture? or gymnast wrist or Distal Radial Epiphysitis).ab,kf,ti. 14 or/12-13 [known injuries]
15 (risk adj3 factor?).ab,hw,kf,ti. 16 or/11,14-15 [injury risk]
17 exp upper extremity/ or exp hand joints/ or elbow joint/ or shoulder joint/ or rotator cuff/ or exp epiphyses/ 18 (axilla or upper extremit* or upper limb? or arm? or forearm? or shoulder? or wrist? or elbow? or rotator cuff or epiphys* or growth plate?).ab,kf,ti. 19 or/17-18 [anatomy]
20 age factors/ or child/ or adolescent/
21 (kid? or pubescen* or prepube* or puberty or teen* or adolescen* or young* or youth? or juvenile or minors or under ag* or school? or girl? or boy? or preadolesc* or young adult* or adolescen* or highschool or junior).ab,kf,ti.
22 or/20-21 [children | young adults] 23 3 and (6 or 16) and 19
24 athletic injuries/
25 ((injur* adj5 (sport? or athlet*)) or overuse injur*).ab,kf,ti. 26 or/24-25 [athletic injuries]
27 and/19,22,26
28 ((young or junior or pe?diatric or school? or highschool or child* or adolescen* or puberty) adj7 (sport? or athlet* or handball or basketball or baseball or swimming or racquet sport? or tennis or volleyball or cricket or javelin) adj7 (risk factor? or injur*)).ab,kf,ti.
29 or/27-28 [athletic injuries in children | young adults] 30 23 or 29
31 remove duplicates from 30
Appendix 1. Continued. Ovid EMBASE
1 baseball/ or basketball/ or “cricket (sport)”/ or exp racquet sport/ or swimming/ or volleyball/ 2 (handball or basketball or baseball or swimming or racquet sport? or tennis or volleyball or cricket or javelin).ab,kw,ti. 3 or/1-2 [rel. sports]
4 “prevention and control”/ or prevention/ or primary prevention/ 5 prevent*.ab,kw,ti.
6
(Manage training programs or (training adj3 (duration or intensity or recovery)) or (match adj5 frequen*) or season duration or Symptom monitoring system or medical help or Intensity monitoring or pitch velocity or Throwing technique or curveballs or Preseason supraspinatus strengthening or Dedicated warm-ups or Pitch-count or rest period).ab,kw,ti.
7 or/4-6 [prevention]
8 (injur* adj15 (handball or basketball or baseball or swimming or racquet sport? or tennis or volleyball or cricket or javelin)).ab,kw,ti. 9 injur*.hw.
10 (handball or basketball or baseball or swimming or racquet sport? or tennis or volleyball or cricket or javelin).ab,kw,ti. 11 9 and 10
12 or/8,11 [rel. sport injuries]
13 shoulder pain/ or exp cumulative trauma disorder/ or stress fracture/
14 (shoulder pain or (shoulder? adj5 (complaint? or disorder? or extertion or flexion or repetitive)) or rotator cuff syndrome or cumulative trauma disorder? or little league or humeral epiphysi* or apophysi* or capitellum or capitellar or stress fracture? or gymnast wrist or Distal Radial Epiphysitis).ab,kw,ti. 15 or/13-14 [known injuries]
16 risk factor/
17 (risk adj3 factor?).ab,hw,kw,ti. 18 or/13,16-17 [injury risk]
19 exp upper limb/ or exp rotator cuff/ or exp epiphysis/ or epiphysis plate/ or epiphysis injury/ 20 (axilla or upper extremit* or upper limb? or arm? or forearm? or shoulder? or wrist? or elbow? or rotator cuff or epiphys* or growth plate?).ab,kw,ti.
21 or/19-20 [anatomy]
22 age/ or exp childhood/ or exp adolescence/ or exp child/
23 (kid? or pubescen* or prepube* or puberty or teen* or adolescen* or young* or youth? or juvenile or minors or under ag* or school? or girl? or boy? or preadolesc* or young adult* or adolescen* or highschool or junior).ab,kw,ti.
24 or/22-23 [children | young adults] 25 3 and (7 or 18) and 21
26 sport injury/
27 ((injur* adj5 (sport? or athlet*)) or overuse injur*).ab,kw,ti. 28 or/26-27 [athletic injuries]
29 and/21,24,28
30 ((young or junior or pe?diatric or school? or highschool or child* or adolescen* or puberty) adj7 (sport? or athlet* or handball or basketball or baseball or swimming or racquet sport? or tennis or volleyball or cricket or javelin) adj7 (risk factor? or injur*)).ab,kw,ti.
31 or/29-30 [athletic injuries in children | young adults] 32 25 or 31
A pp end ix 2 . R isk f ac to rs f or e lb ow a nd /o r s ho ul de r p ai n i n y ou th b as eb al l p la ye rs . N on m od ifi ab le R is k Fac tor s El bo w p ain Sh ou ld er p ain El bo w a nd /o r s ho ul de r p ai n Ri sk fa ct or Re fer en ce var iab le U ni va ria te o dd s ra tio w ith 9 5% co nfi den ce in ter val M ul tiv ar ia te o dd s ra tio w ith 9 5% co nfi den ce in ter val U ni va ria te o dd s ra tio w ith 9 5% co nfi den ce in ter val M ul tiv ar ia te o dd s ra tio w ith 9 5% co nfi den ce in ter val U ni va ria te o dd s ra tio w ith 9 5% co nfi den ce in ter val M ul tiv ar ia te o dd s ra tio w ith 9 5% co nfi den ce in ter val Sex M al e s ex 1 2. 22 1.4 9-3 .3 1 1.69 1.0 9-2. 62 Ag e 9 y ea rs ≤8 y ea rs 2 4.1 5 2. 39 –7. 58 3.1 9 1.76 –6 .0 2 10 y ea rs ≤8 y ea rs 2 ≤9 y ea rs 3 6.1 6 4. 03 3. 67– 10 .9 4 2. 17− 8. 08 3.1 8 3. 02 1.76 –6 .0 0 1.6 0– 6.1 5 2. 36 2. 01 1.38 –4 .2 5 1.0 9-3 .8 7 1.9 5 1.0 4−3 .8 1 11 y ea rs o ld ≤8 y ea rs 2 ≤9 y ea rs 3 8. 41 8.7 9 4.7 3– 15 .7 0 4. 96− 17 .0 7 3. 93 5. 05 2. 01 –7. 95 2. 73 –1 0.1 4 2.7 7 3.5 2 1.50 –5 .29 2. 04 − 6. 46 3.1 2 1.7 1− 6. 01 11 -1 2 y ea rs o ld <1 0 y ea rs 4 3.38 2. 60 -4 .38 > 1 1 y ea rs o ld < 1 1 y ea rs old 5 2. 82 1.3 0-6.1 0 12 y ea rs o ld ≤9 y ea rs 3 ≤1 0 y ea rs 6 16 .53 2. 74 9. 42 −3 1.8 7 1.55 -5 .0 5 6.7 8 1.9 1 3. 57 –1 3. 88 1.0 4-3 .6 3 4.0 8 2.4 0− 7.4 4 3.1 4 1.6 4− 6. 29 > 1 2 y ea rs o ld < 1 0 y ea rs 7 2.9 1 1.1 4-7. 41 13 -15 y ea rs o ld <1 0 y ea rs 4 5.7 0 4. 42 -7 .3 6 16 -1 7 y ea rs o ld <1 0 y ea rs 4 9. 53 7. 42 -1 2. 24 Per a dd itio nal y ear 1.29 1.1 2-1.4 8 Bod y H ei gh t Per a dd itio nal in ch 8 1.7 7 1.1 7-2. 66 > 15 0 c m < 15 0 c m 5 2. 02 1.0 7-3. 82 >6 1 i nc he s ( >15 5c m ) 7 0. 35 0. 12 -0. 99 Ba se ba ll exp er ie nc e >1 y ea r 9 1.4 4 1.03 -2 .03 2-3 y ea rs <2 y ea rs 3 2. 63 1.75− 4. 04 1.6 7 1.0 8-2. 62 2.5 -3 .5 y ea rs ≤1 .5 y ea rs 2 4.0 8 1.5 6– 14 .03 3-4 y ea rs <2 y ea rs 3 5.9 7 4.0 2− 9.0 7 1.9 8 1.2 9−3 .12 3.5 -4 .5 y ea rs ≤1 .5 y ea rs 2 6. 65 2. 50 –23. 09 3.38 1.14 –14 .5 5 4-5 y ea rs <2 y ea rs 3 7. 37 4. 80 -1 1.5 7 2. 46 1.5 3− 4. 01 4. 5-6 y ea rs ≤1 .5 y ea rs 2 8.5 0 2. 93– 31 .2 1 4.0 0 1.2 2– 18 .13 ≥5 y ea rs <2 y ea rs 3 11 .55 6. 89 -1 9. 74 3.9 6 2. 27− 6. 92
8
A pp en di x 2 . C on tinu ed . N on m od ifi ab le R is k Fac tor s El bo w p ain Sh ou ld er p ain El bo w a nd /o r s ho ul de r p ai n Ri sk fa ct or Re fer en ce var iab le U ni va ria te o dd s ra tio w ith 9 5% co nfi den ce in ter val M ul tiv ar ia te o dd s ra tio w ith 9 5% co nfi den ce in ter val U ni va ria te o dd s ra tio w ith 9 5% co nfi den ce in ter val M ul tiv ar ia te o dd s ra tio w ith 9 5% co nfi den ce in ter val U ni va ria te o dd s ra tio w ith 9 5% co nfi den ce in ter val M ul tiv ar ia te o dd s ra tio w ith 9 5% co nfi den ce in ter val Bi om ec han ic al ch ar ac te ris ti cs Sh ou ld er e xt er nal ro ta tio n < 13 0 5 1.9 8 1.0 1-3. 87 M ax . s ho ul de r e xt er na l ro ta tio n s tre ng th >80N 5 4.1 1 1.4 7-11. 55 M ax . s ho ul de r i nt er na l ro ta tio n s tre ng th >1 00 N 5 2. 04 1.0 8-3 .9 0 Imag ing ab norm al it ie s M ed ial ep ic on dy le irr eg ul ar ity N or m al m ed ia l ep ic on dy le 4 2.5 8 1.9 9-3 .3 6 3. 22 2. 44-4. 27 M ed ial ep ic on dy le hy pe rt ro phy N or m al m ed ia l ep ic on dy le 4 3.1 8 2. 76 -3 .6 5 2. 03 1.7 5-2 .3 6 M ed ial ep ic on dy le fra gm ent at io n N or m al m ed ia l ep ic on dy le 4 4.1 0 3. 63 -5 .8 4 4.0 4 3.1 6-5. 22 Ca pi te lla r Os te oc hon dr iti s D iss ec an s 4 2.9 4 1.8 0-4.8 0 2. 34 1.4 0-4.1 1 Bod y W ei gh t 86 -1 00 l bs ( 39 -4 5k g) <7 1 l bs (< 32 k g) 7 4.1 1 1.7 1-9. 86 ≥1 01 l bs ( >4 5k g) <7 1 l bs (< 32 k g) 7 5. 39 1.7 4-16 .7 0
A pp en di x 2 . C on tinu ed . N on m od ifi ab le R is k Fac tor s El bo w p ain Sh ou ld er p ain El bo w a nd /o r s ho ul de r p ai n Ri sk fa ct or Re fer en ce var iab le U ni va ria te o dd s ra tio w ith 9 5% co nfi den ce in ter val M ul tiv ar ia te o dd s ra tio w ith 9 5% co nfi den ce in ter val U ni va ria te o dd s ra tio w ith 9 5% co nfi den ce in ter val M ul tiv ar ia te o dd s ra tio w ith 9 5% co nfi den ce in ter val U ni va ria te o dd s ra tio w ith 9 5% co nfi den ce in ter val M ul tiv ar ia te o dd s ra tio w ith 9 5% co nfi den ce in ter val Pla yi ng pos it io n Pi tc he r O ut field er 6 3 2 4 5.1 7 4.0 1 4. 22 2. 27 2. 68 -1 0. 71 2. 78 −5 .8 6 2. 66 –6 .74 1.9 2– 2. 70 4. 24 1.47 2.62 2.1 6-9. 03 0. 96 –2 .2 5 1.5 3– 4.5 0 2.1 3 4.1 9 1.3 4− 3.3 2 2. 48 –7. 13 2.9 9 1.6 5– 5.4 3 Fie ld er 1 2.1 6 1.8 4-2 .5 4 1.43 1.1 8-1.7 5 N on-pi tc he r 10 2.38 1.28 -4 .4 4 5 4.5 0 2. 42-8. 37 Ca tc he r O ut field er 6 3 2 4 4. 55 3. 66 3.7 5 2.5 7 2. 03 -1 0. 65 2.4 7− 5.4 2 2. 32 –6 .0 8 2. 03 -3 .2 5 3. 76 1.5 6 2. 29 1.62 -9 .0 6 1.0 1– 2. 39 1.3 3–3. 96 1.9 6 2. 83 1.2 0−3 .13 1.59 –4 .9 8 2. 02 1.0 7–3. 76 Fie ld er 1 1.9 9 1.65 -2 .39 1.4 0 1.1 2-1.7 6 In fie lde r O ut field er 6 3 2 4 2. 04 1.7 7 1.7 5 1.33 1.03 -4 .3 0 1.3 7− 2. 28 1.25 –2 .4 6 1.1 4-1.5 6 1.5 7 1.5 4 1.1 5− 2.1 4 1.0 0– 2. 40 In ju ry h is tor y Pr io r o ve ru se i nj ur y 10 3. 42 1.7 2-6.7 7 Pr io r p itc hi ng r el at ed in jur y 11 2. 46 1.59 -3 .7 9 H ist or y o f s ho ul de r pai n 2 2. 04 1.3 9–3. 00 4.1 8 2.7 7– 6. 31 3. 34 2.1 6– 5.1 7 H ist or y o f e lb ow p ai n 2 7. 08 4. 98 –1 0. 20 5.7 0 3. 91 –8 .4 1 2. 20 1.5 1–3. 20 1.53 1.0 0– 2. 31 Re po rt in g a rm fat igu e 7 5.9 4 3. 48 -1 0.1 4 4.1 4 2. 76 -6 .2 2 Te chn iqu e Th ro w in g c ur ve ba lls 12 1.6 6 1.0 9-2 .5 3
8
A pp en di x 2 . C on tinu ed . N on m od ifi ab le R is k Fac tor s El bo w p ain Sh ou ld er p ain El bo w a nd /o r s ho ul de r p ai n Ri sk fa ct or Re fer en ce var iab le U ni va ria te o dd s ra tio w ith 9 5% co nfi den ce in ter val M ul tiv ar ia te o dd s ra tio w ith 9 5% co nfi den ce in ter val U ni va ria te o dd s ra tio w ith 9 5% co nfi den ce in ter val M ul tiv ar ia te o dd s ra tio w ith 9 5% co nfi den ce in ter val U ni va ria te o dd s ra tio w ith 9 5% co nfi den ce in ter val M ul tiv ar ia te o dd s ra tio w ith 9 5% co nfi den ce in ter val Tr ainin g 16 -3 6 w ee kl y t ra in in g hou rs ≤1 0. 5 tra in in g hou rs 2 2. 30 1.4 2–3. 84 2. 33 1.34 –4 .15 1.7 5 0. 98 –3. 28 2. 00 1.0 7–3. 92 Pr ac tic in g ≥ 3 h ou rs pe r d ay i n w ee ke nd s 1 1.63 1.0 2-2. 61 Pr ac tic e < 3 h ou rs o n w ee kd ay s 1 1.27 1.0 1-1.6 0 Tr ai ni ng e ve ry d ay 5 1.9 6 1.0 2-3 .7 9 W ei gh t li ftin g 7 1.9 9 1.0 7-3. 70 Pl ay in g b as eb al l ou ts id e t he l ea gu e 7 2. 35 1.2 6-4.38 Se lf-co nfide nc e Sa tis fa cti on w ith per fo rm an ce 7 0. 83 0. 70 -0. 99 0.7 5 0.6 5-0. 86 A m ou nt & in te nsi ty of p itc hin g ac ti vi ti es > 1 00 g am es p er y ea r 6 2. 59 1.3 4-5 .2 5 2. 62 1.3 0-5.4 9 30 0-59 9 p itc he s (c ur re nt se ason ) <3 00 pi tc he s 7 0. 47 0. 32 -0. 92 0. 47 0. 24 -0. 92 0.4 0 0. 24 -0. 65 0. 51 0. 33 -0. 80 >6 00 p itc he s ( cu rr en t se ason ) <3 00 pi tc he s 7 0.1 9 0. 05-0.6 8 N um be r o f i n-ga m e pi tc he s Pe r 1 0 ad di tio nal pi tc he s 7 1.1 5 1.0 8-1.2 3 50 -7 4 i n-ga m e p itc he s 1-24 in -g am e pi tc he s 7 1.61 1.0 4-2 .4 9
A pp en di x 2 . C on tinu ed . N on m od ifi ab le R is k Fac tor s El bo w p ain Sh ou ld er p ain El bo w a nd /o r s ho ul de r p ai n Ri sk fa ct or Re fer en ce var iab le U ni va ria te o dd s ra tio w ith 9 5% co nfi den ce in ter val M ul tiv ar ia te o dd s ra tio w ith 9 5% co nfi den ce in ter val U ni va ria te o dd s ra tio w ith 9 5% co nfi den ce in ter val M ul tiv ar ia te o dd s ra tio w ith 9 5% co nfi den ce in ter val U ni va ria te o dd s ra tio w ith 9 5% co nfi den ce in ter val M ul tiv ar ia te o dd s ra tio w ith 9 5% co nfi den ce in ter val A m ou nt & in te nsi ty of p itc hin g ac ti vi ti es ≥7 5 i n-ga m e p itc he s 1-24 in -g am e pi tc he s 7 3. 22 1.8 4-5 .6 1 2. 48 1.3 3-4. 60 Pi tc he d i nn in gs p er ga m e Pe r ad di tio nal in nin g 7 1.21 1.0 7-1.3 6 Pi tc he d i nn in gs p er se ason Pe r 1 0 ad di tio nal in nin gs 7 0.5 4 0. 42 -0. 69 Pi tc he d g am es p er se ason Pe r ad di tio nal ga m e 7 0. 85 0. 80 -0. 91 Pi tc hi ng f or m ul tip le t ea m s w ith ov er la pp in g se ason s 12 1.85 1.0 2-3.38 Pi tc hi ng o n co ns ec ut iv e d ay s 12 2. 53 1.1 4-5. 60 Pi tc hin g m ul tip le ga m es a d ay 12 1.89 1.0 3-3 .4 9 >5 0 f or ce d p itc he s a d ay 2. 31 2. 04 -2. 60 1.28 1.0 8– 1.5 2 >4 d ay s/ w ee k w / fo rc ed p itc he s 1 1.2 0 1.0 1-1.4 1 >1 00 f or ce d p itc he s a w ee k 1 1.5 0 1.3 1-1.7 1
8
A pp en di x 3 . C ha ra ct er ist ic s o f s tu di es r ep or tin g i nc id en ce o f o ve ru se i nj ur ie s o f t he e lb ow a nd s ho ul de r St ud y i nf orm at ion St ud y p op ul at io n O ut com es Au th or ( ye ar ), co unt ry D esi gn Sa m pl e siz e ( F, M ) Ath leti c ex po su re M ea n a ge i n y ea rs (S D a nd /o r r an ge ) O ve ru se d efi ni tio n a nd p er io d o f m ea sur em ent Ty pe a nd l ev el o f sp or ts An at om ic lo ca tio n Re su lts In cid en ce H ic ke y 13 (1 99 7) , Au st ra lia Retr os pe cti ve coh or t 49 ( al l F ) 72 se ason s 16 .8 ( 15 .3 -1 8. 7) Ch ro ni c o ve rl oa d d ur in g o ne se ason pr ese nt ed t o t he m ed ic al pr ac tit io ne rs o f t he A IS sp or ts m ed ic in e d ep ar tm en t Ba sk et ba ll; e lit e at hl et es Shou ld er / ar m /e lbo w (w ris t n ot in cl ud ed ) 1 in jur y 0. 01 p er p la ye r p er se ason Kra jn ik 14 (2 01 0) , U SA Retr os pe cti ve coh or t N ot specifi ed 39 9, 52 2 AE N ot s pe ci fie d, h ig h sc ho ol a ge In ju ry cl as sifi ed as ch ro ni c/ ov er us e th at o cc ur re d a s a r es ul t o f a p ra ct ice / co mp et itio n an d r equ ire d m ed ic al at ten tio n an d r es ul te d i n p ar tic ip at io n re st ric tio n ≥ 1 d ay Sof tb al l; h ig h sc ho ol at hl et es Shou ld er 14 in jur ie s 0. 35 p er 10,0 00 A E† Lep pan en 15, 20 17 , F in la nd Pr os pec tiv e coh or t 20 1 ( F1 01 , M1 00 ) 59 ,59 9 A E hou rs 15 ,7 ( ± 1 .7 ) A n i nj ur y ca us ed b y a r ep et iti ve m ic ro tr au m a a nd h ad n o s in gl e id ent ifi ab le e ve nt c au sin g th e in jur y an d c au se d f ul l or p ar tia l a bse nc e fro m sp or ts p ar tic ip at io n. Ba sk et ba ll; t w o hi gh es t ju ni or le agu es Shou ld er N o in jur ie s 0. 0 p er 10,0 00 A E hou rs El bo w 1 in jur y 0. 17 p er 10,0 00 A E hou rs O lse n 16 (2 00 6) , N or wa y Pr os pec tiv e coh or t 42 8 ( F 3 21 , M 1 07 ) 41 ,2 42 A E hou rs No t s pec ifi ed , 1 7-ye ar gr oup In ju ry w ith g ra du al o ns et w ith ou t a ny kn ow n tr au m a th at cau se d th e p la ye r to re qu ire m ed ic al tre at m en t o r m iss pa rt o f o r r es t o f t he m at ch o r t ra in in g se ss io n. Han db al l; am at eu rs Shou ld er 1 in jur y 0. 24 p er 10,0 00 A E hou rs El bo w N o in jur ie s 0. 00 p er 10,0 00 A E hou rs Ro os 17 (2 015 ), US A Retr os pe cti ve coh or t N ot spec ifi ed N ot specifi ed N ot s pe ci fie d, h ig h sc ho ol a ge In ju ry cl as sifi ed as ch ro ni c/ ov er us e th at o cc ur re d a s a r es ul t o f a p ra ct ice / co mp et itio n an d r equ ire d m ed ic al at ten tio n an d r es ul te d i n p ar tic ip at io n re st ric tio n ≥ 1 d ay Ba se ba ll; hi gh sc ho ol at hl et es Shou ld er 10 0 in jur ie s 0. 64 p er 10,0 00 A E El bo w 55 in jur ie s 0. 35 p er 10,0 00 A E So ft ba ll; hi gh sc ho ol at hl et es Shou ld er 63 in jur ie s 0. 54 p er 10,0 00 A E El bo w 30 in jur ie s 0. 26 p er 10,0 00 A E Ba sk et ba ll (M ); hi gh s ch oo l at hl et es Shou ld er 4 in jur ie s 0. 03 p er 10,0 00 A E El bo w N o in jur ie s 0. 00 p er 10,0 00 A E Ba sk et ba ll (F ); hi gh s ch oo l at hl et es Shou ld er 9 in jur ie s 0. 05 p er 10,0 00 A E El bo w 1 in jur y 0. 01 p er 10,0 00 A E Vo lle yb all ; h ig h sc ho ol at hl et es Shou ld er 59 in jur ie s 0. 38 p er 10,0 00 A E El bo w 2 in jur ie s 0. 01 p er 10,0 00 A E
A pp en di x 3 . C on tinu ed . St ud y i nf orm at ion St ud y p op ul at io n O ut com es Au th or ( ye ar ), co unt ry D esi gn Sa m pl e siz e ( F, M ) Ath leti c ex po su re M ea n a ge i n y ea rs (S D a nd /o r r an ge ) O ve ru se d efi ni tio n a nd p er io d o f m ea sur em ent Ty pe a nd l ev el o f sp or ts An at om ic lo ca tio n Re su lts In cid en ce Sap er 18 (2 01 7) , U SA Retr os pe cti ve coh or t N ot specifi ed 1,7 34 ,19 8 AE N ot s pe ci fie d, h ig h sc ho ol a ge In ju ry cl as sifi ed as ch ro ni c/ ov er us e th at o cc ur re d a s a r es ul t o f a p ra ct ice / co mp et itio n an d r equ ire d m ed ic al at ten tio n an d r es ul te d i n p ar tic ip at io n re st ric tio n ≥ 1 d ay Ba se ba ll; H ig h sc ho ol at hl et es Shou ld er 89 in jur ie s 0. 51 p er 10,0 00 A E El bo w 50 in jur ie s 0. 29 p er 10,0 00 A E Va n d er S lu is 19 (2 01 6) , N L Pr os pec tiv e coh or t 73 ( F 2 8, M 45 ) 26 ,39 7 A E hou rs ‡ 12 .4 ( ± 1 .1) In ju rie s t ha t c ou ld n ot b e l in ke d t o a sin gl e id en tifi ab le ev en t a nd re su lte d in a ny s ym pt om s o r d iff ic ul tie s i n pa rt ic ip at in g in tra in in g/ co m pe tit io n, re du cin g o f t ra in in g v ol um e o r red uc ed pe rf or m an ce Te nn is ; e lit e at hl et es Shou ld er 14 in jur ie s 5. 30 p er 1 0, 00 0 A E hou rs ‡ El bo w 7 in jur ie s 2. 65 p er 1 0, 00 0 A E hou rs ‡ Th ei se n 20 (2 01 3) , Lu xe m bo ur g Pr os pec tiv e coh or t 27 9 ( F 9 5, M 1 84 ) N ot specifi ed 14 .6 (1 2-19 ) In ju ry du e to m ic ro tr au m a c au se d by c hr on ic o ve rlo ad w ith ou t a s in gl e, id en tif ia ble cau se th at fo rc es th e at hl et e t o i nt er ru pt o r m od ify h is/ he r us ua l s po rt in g a ct iv iti es fo r a t l ea st on e u ni t ( tim e-lo ss d efi ni tio n) . Vo lle yb all ; pu bl ic s po rt s sc ho ol Shou ld er 2 in jur ie s 0. 10 p er p er so n p er se ason El bo w N o in jur ie s 0. 00 p er p er so n p er y ea r Han db al l; p ub lic sp or ts sch oo l Shou ld er N o in jur ie s 0. 00 p er p er so n p er y ea r El bo w 1 in jur y 0. 02 p er p er so n p er y ea r AE : a th le tic e xp os ur es ; F : F em al e; M : M al e; S D ; s ta nd ard d ev ia tio n; * gi ve n a s a m ou nt o f i nj ur ie s p er p er so n p er y ea r o r s ea so n; † i nc id en ce o f b as eb al l in ju rie s n ot e xt ra ct ed as s tu dy p op ul at io n o ve rla ps w ith s tu dy o f S ap er e t a l. 18 ; ‡ c al cu la te d w ith da ta p ro vi de d i n t he a rt ic le
8
A pp en di x 4 . C ha ra ct er ist ic s o f s tu di es r ep or tin g p ai n r el at ed t o o ve ru se o f t he e lb ow a nd s ho ul de r St ud y i nf orm at ion St ud y p op ul at io n O ut com es Au th or ( ye ar ), co unt ry D esi gn Sa m pl e s iz e (F , M) M ea n a ge in y ea rs (S D a nd /o r ra ng e) Ty pe a nd l ev el of s po rt s Po sit io n Pa in d efi ni tio n a nd p er io d o f m ea sur em ent An at omi c lo ca tio n Re su lts In cid en ce Pr ev al en ce H ist or of pai Ad ams 21 (1 965 ), U SA Cr os s-se ct io nal 80 ( al l M ) N ot spec ifi ed , (9 -1 4) Ba se ba ll: Li ttl e a nd P on y lea gu e Pi tc he rs An y p ai n o r s or en es s o f t he e lb ow w hil e p itc hin g El bo w 34 p laye rs 45 % Ah m ad 22 (2 01 7) , U SA Pr os pec tiv e coh or t 22 3 ( al l M ) 14 .3 (1 0-18 ) Ba se ba ll: Li ttl e l ea gu e, ad ol es ce nt a nd hi gh s ch oo l Al l po sit io ns Le ve l o f p ai n o r di sc om fo rt o f t he ar m d ur in g t he la st t im e p la yi ng ba se ba ll pl ay in g w ith a rm pa in /d isc om for t Ar m 60 p laye rs 27 % no t p la yi ng d ue to a rm p ai n/ di sc om for t 15 p la ye rs 7% Ch al m er s 11 (2 015 ), U SA Cr os s-se ct io nal 42 0 ( no t spec ifi ed ) 14 .9 ( 9-22 ) Ba se ba ll: Al l le ve ls Pi tc he rs An y c ur re nt d isc om fo rt i n t he sh ou ld er o r e lb ow w hi le p itc hi ng Shou ld er 68 p laye rs 16% El bo w 76 p laye rs 18% G ra na 23 (1 98 0) , U SA Pr os pec tiv e coh or t 73 ( no t spec ifi ed ) 17 (1 4-19) Ba se ba ll: h ig h sc ho ol Pi tc he rs At l ea st o ne e pi so de o f p ai n a bo ut t he el bo w a s a r es ul t o f t hr ow in g (w he th er it w as s ev er e e no ug h t o i m pa ir th ro w in g a bili ty ) d ur in g a 5 -m ont h per io d. El bo w 42 p laye rs 58 % G ug en he im 24 (1 97 6) , U SA Cr os s-se ct io nal 59 5 ( al l M ) 11 .4 (9 -1 3) Ba se ba ll: L itt le Le ag ue Pi tc he rs El bo w d isc om fo rt d ur in g t he ir pi tc hi ng c ar eer El bo w 10 0 p laye rs 17 % H an g 25 (2 00 4), Ta iw an Cr os s-se ct io nal 34 3 ( no t spec ifi ed ) 11 .6 (9. 5-12) Ba se ba ll: L itt le Le ag ue Al l po sit io ns Pa in o r d isc om fo rt i n t he m ed ia l as pe ct o f t he e lb ow d ur in g o r a fte r th ro w in g p rac tic e t hr ou ghou t t he se ason El bo w 18 0 p laye rs 52 % H ar ad a 5 (2 01 0) , J ap an Pr os pec tiv e coh or t 29 4 ( no t spec ifi ed ) 11 (9 -1 2) Ba se ba ll: y ou th lea gu e t ea m s Pi tc he rs An y h ist or y o f a n e pi so de o f e lb ow pa in d ur in g t hr ow in g El bo w 11 4 p laye rs 39 % Ka ne ma tsu 9 (2 015 ), J ap an Cr os s-se ct io nal 20 55 ( no t spec ifi ed ) N ot spec ifi ed (9 -1 2) Ba se ba ll: re gio nal cha m pi on sh ip Al l po sit io ns An y h ist or y o f a n e pi so de o f s ho ul de r pai n Shou ld er 27 5 p laye rs 13 % Ki da 26 (2 01 6) , Jap an Cr os s-se ct io nal 57 6 ( al l M ) 16 .3 ( 15 -1 7) Ba se ba ll; hi gh sc ho ol s ki ll tra in in g c am p Al l po sit io ns H ist or y o f e lb ow p ai n a ss oc ia te d w ith th ro w in g El bo w 36 1 p laye rs 63% Cu rr en t e lb ow p ai n a ss oc ia te d w ith th ro w in g El bo w 10 8 p laye rs 19 %
A pp en di x 4 . C on tinu ed . St ud y i nf orm at ion St ud y p op ul at io n O ut com es Au th or ( ye ar ), co unt ry D esi gn Sa m pl e s iz e (F , M) M ea n a ge in y ea rs (S D a nd /o r ra ng e) Ty pe a nd l ev el of s po rt s Po sit io n Pa in d efi ni tio n a nd p er io d o f m ea sur em ent An at omi c lo ca tio n Re su lts In cid en ce Pr ev al en ce H ist or of pai Ki da 27 (2 01 4), Jap an Cr os s-se ct io nal 24 33 ( 2 F , 24 31 M ) 14 .5 ( 15 -1 7) Ba se ba ll: hi gh sc ho ol s ki ll tra in in g c am p Al l po sit io ns H ist or y o f e lb ow p ai n a ss oc ia te d w ith th ro w in g El bo w 13 87 p la ye rs 57 % Cu rr en t e lb ow p ai n a ss oc ia te d w ith th ro w in g El bo w 41 6 p laye rs 17 % Ly m an 7 (2 00 1) , U K Pr os pec tiv e coh or t 29 8 ( no t spec ifi ed ) 10 .8 (8. 1-12 .4 ) Ba se ba ll; yo ut h b as eb al l pa rk s Pi tc he rs Pa in o r s or en es s i n t he e lb ow o r sh oul de r j oint s d ur in g o r af te r pi tc hi ng d ur in g 1 o r 2 s ea so ns Shou ld er 95 p laye rs 32 % El bo w 76 p laye rs 26 % M ai r 28 (2 00 4), U SA Cr os s-se ct io nal 79 ( al l M ) 11 .6 ( 8-15 ) Ba se ba ll: Li ttl e lea gu e N ot spec ifi ed H ist or y o f s ho ul de r p ai n i n t he th ro w in g a rm Shou ld er 26 p laye rs 33 % Sh ou ld er p ai n o r a ch in g a fte r th ro w in g d ur in g t he c ur re nt se as on Shou ld er 13 p laye rs 16% Cu rr en t s ho ul de r s ym pt om s r el at ed to t hr ow in g Shou ld er 7 p laye rs 9% M ak hn i 10 (2 015 ), U SA Cr os s-se ct io nal 20 3 ( no t spec ifi ed ) 15 .2 ( 8-18 ) Ba se ba ll: Li ttl e Le ag ue Al l po sit io ns Fr eq ue nc y o f ar m p ai n w hi le th ro w in g Ra re ly Ar m 89 p laye rs 44% So m eti m es 61 p laye rs 30 % O fte n N o p laye rs 0% Alw ay s N o p laye rs 0% Fr eq ue nc y o f a rm pa in t he d ay a fte r th ro w in g Ra re ly Ar m 75 p laye rs 37 % So m eti m es 63 p laye rs 31 % O fte n 22 p laye rs 11 % Alw ay s 2 p laye rs 1% M at su ura 6 (2 01 3) , J ap an Pr os pec tiv e coh or t 44 9 ( no t spec ifi ed ) 10 .1 ( 7-11 ) Ba se ba ll; re gio nal su m m er cha m pi on sh ip Al l po sit io ns An y e pi so de s o f e lb ow p ai n d ur in g th e se ason El bo w 13 7 p laye rs 31 % Ya ng 12 (2 01 4), U SA Cr os s-se ct io nal 75 4 ( al l M ) 14 .1 ( ± 2 .6 ) Ba se ba ll: no t spec ifi ed Pi tc he rs Fr eq ue nc y o f ar m p ai n w he n pi tc hi ng i n t he pr ev io us 1 2 m on ths . So m eti m es Ar m 24 3 p laye rs 34% O fte n 32 p laye rs 4%
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A pp en di x 4 . C on tinu ed . St ud y i nf orm at ion St ud y p op ul at io n O ut com es Au th or ( ye ar ), co unt ry D esi gn Sa m pl e s iz e (F , M) M ea n a ge in y ea rs (S D a nd /o r ra ng e) Ty pe a nd l ev el of s po rt s Po sit io n Pa in d efi ni tio n a nd p er io d o f m ea sur em ent An at omi c lo ca tio n Re su lts In cid en ce Pr ev al en ce H ist or of pai Yu ku ta ke 29 (2 015 ), J ap an Pr os pec tiv e coh or t 38 9 ( no t spec ifi ed ) 10 .1 ( ± 0 .9 ) Ba se ba ll: Li ttl e Le ag ue Th ro wi ng ar m Sh ou ld er o r e lb ow p ai n w hi le th ro w in g i n t he p re ce di ng 1 2 m on th s Shou ld er or e lb ow 14 5 p ar tic ip an ts 37 % Ta ka gi sh i 1 (2 01 7) , J ap an Retr os pe cti ve coh or t 789 4 ( 7589 M , 3 05 F ) 9.9 ( ± 1 .4 ) Ba se ba ll; el em en tar y sc ho ol Al l po sit io ns an y n on -t ra um at ic c on di tio n r es ul tin g in th e s ubje ct e xp er ien ci ng sh ou ld er or e lb ow p ai n f or > 1 w ee k i n t he p as t yea r Shou ld er 63 1 p laye rs 8% El bo w 97 1 p laye rs 12 % So m m er vold 30, 2 01 7, N or w ay ‡ Pr os pec tiv e int er ve nt io n stu dy 10 5 ( al l F ) N ot spec ifi ed , (< 16 y ea rs te am s) Han db al l; el ite Al l po sit io ns Pa in i n t he t hr ow in g s ho ul de r a t ba se lin e ( be fo re th e int er ve nt io n) Shou ld er 34 p laye rs 32 % Sa ka ta 31, (2 01 6) , J ap an Pr os pec tiv e coh or t 353 ( 29 8 M , 22 F ) N ot spec ifi ed , (6 -1 2) Ba se ba ll; re gio nal le agu es Al l po sit io ns Pa in o f t he e lb ow o r s ho ul de r t ha t la st ed > 2 w ee ks , t ha t c au se d a bs en ce of a g am e o r w as r ec ur re nt i n a 1 2-m on th p er io d Shou ld er 34 p laye rs 10% El bo w 88 p laye rs 25% Py tia k 32, (2 01 7) , U SA Pr os pec tiv e coh or t 25 ( no t spec ifi ed ) 11 .5 (1 0-1 3) Ba se ba ll l itt le lea gu e Al l po sit io ns An y a rm p ai n i n t he s ho ul de r o r e lb ow du rin g on e se ason (1 2 w ee ks ) Shou ld er 4 p laye rs 16% El bo w 5 p laye rs 20 % O to sh i 4, (2 01 7) , J ap an Cr os s-se ct io nal 42 49 ( no t spec ifi ed ) N ot spec ifi ed (6 -1 7) Ba se ba ll; no t spec ifi ed Al l po sit io ns An y h ist or y o f p ai n o r d isc om fo rt i n th e d om in ant e lb ow d ur in g t hr ow in g El bo w 23 09 p laye rs 54% O liv eira 33, (2 017 ), B ra zil Cr os s-se ct io nal 98 ( 37 M , 61 F ) 14 .2 ( ± 2 .1) Vo lle yb all ; n ot spec ifi ed Cur re nt sh oul de r p ain Shou ld er 39 p la ye rs 40% Sh ou ld er p ai n d ur in g t he l as t y ea r Shou ld er 51 p laye rs 52 % 58 ( 44 M , 14 F) Ba sk et ba ll; no t s pec ifi ed Cur re nt sh oul de r p ain Shou ld er 24 p laye rs 41 % Sh ou ld er p ai n d ur in g t he l as t y ea r Shou ld er 27 p laye rs 47 % 7 8 ( 49 M , 29 F) Han db al l; no t spec ifi ed Cur re nt sh oul de r p ain Shou ld er 38 p laye rs 49 % Sh ou ld er p ai n d ur in g t he l as t y ea r Shou ld er 49 p laye rs 63% M at su ura 2, (2 01 7) , J ap an Retr os pe cti ve coh or t 90 0 ( no t spec ifi ed ) 9. 5 ( 7-11 ) Ba se ba ll; re gio nal su m m er cha m pi on sh ip Al l po sit io ns An y e pi so de s o f s ho ul de r o r e lb ow pa in t ha t r es ul te d i n r es tr ic tio n o f pa rt ic ip at io n f or ≥ 1 d ay d ur in g o ne yea r Shou ld er 165 p la ye rs 18% El bo w 31 7 p laye rs 35 %
A pp en di x 4 . C on tinu ed . St ud y i nf orm at ion St ud y p op ul at io n O ut com es Au th or ( ye ar ), co unt ry D esi gn Sa m pl e s iz e (F , M) M ea n a ge in y ea rs (S D a nd /o r ra ng e) Ty pe a nd l ev el of s po rt s Po sit io n Pa in d efi ni tio n a nd p er io d o f m ea sur em ent An at omi c lo ca tio n Re su lts In cid en ce Pr ev al en ce H ist or of pai Fr isc h 34, (2 01 7) , U SA Cr os s-se ct io nal 17 5 ( no t spec ifi ed ) N ot spec ifi ed (1 2-1 8) Vo lle yb all ; hi gh s ch oo l Al l po sit io ns An y h ist or y o f n on -t ra um at ic p ai n in t he s ho ul de r t ha t w as r el at ed t o vo lle yb all Shou ld er 70 p laye rs 40% Iw am e 35, (2 01 6) , J ap an Cr os s-se ct io nal 16 05 ( no t spec ifi ed ) 10 .1 ( 12 -1 6) Ba se ba ll; re gio nal su m m er cha m pi on sh ip Al l po sit io ns An y p as t e pi so de s o f e lb ow p ai n dur in g o r af te r t hr ow in g p ra ct ic e El bo w 49 9 p laye rs 31 % M at su ura 3, (2 01 6) , J ap an Cr os s-se ct io nal 15 63 (15 04 M , 59 F) N ot spec ifi ed (9 -1 2) Ba se ba ll; re gio nal su m m er cha m pi on sh ip Al l po sit io ns H ist or y o f a n e pi so de o f s ho ul de r or e lb ow p ai n t ha t r es ul te d i n par tic ip at io n r es tr ic tio n f or > 1 d ay Shou ld er 24 9 p laye rs 16% El bo w 45 6 p laye rs 29 % Gr ee nbe rg 8, (2 01 7) , U SA Cr os s-se ct io nal 84 ( al l M ) 11 .5 (8 -1 4) Ba se ba ll; Li ttl e L ea gu e & Pr iv at e b as eb al l ac ad em ie s Al l po sit io ns Pr es en ce o f s ho ul de r o r e lb ow p ai n w ith t hr ow in g d ur in g t he p as t 3 0 d ay s. Shou ld er or El bo w 16 p laye rs 19 % Sk illin gt on 36,(2 01 7) , U SA Cr os s-se ct io nal 14 ( al l F ) 16 .5 (1 4-1 8) So ft ba ll; Am at eu r Pi tc he rs H ist or y o f s ho ul de r p ai n Shou ld er 5 p laye rs 36% F: f em al e, M : m al e, S P: s ho ul de r p ai n, E P: e lb ow p ai n *S om e p la ye rs p ar tic ip at ed i n t he s tu dy o nc e, o th er s t w ice o r t hr ee o r f ou r t im es ; ‡ o nl y b as el in e ( pr e-in te rv en tio n) p re va le nc e wa s e xt ra ct ed; # n ot s pe ci fie d
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A pp en di x 5 . C ha ra ct er ist ic s o f s tu di es r ep or tin g r isk f ac to rs o ve ru se i nj ur ie s a nd p ai n o f t he e lb ow a nd s ho ul de r St ud y i nf orm at ion St ud y p op ul at io n O ut com es Au th or (y ea r), co unt ry D esi gn Sa m pl e s iz e (F , M) M ea n a ge in y ea rs ( SD or ra nge ) Ty pe a nd le ve l o f s po rt s O ut co me de fin iti on Lo ca tio n Ri sk fa ct or Re fer en ce var iab le † U ni va ria te O R (9 5% C I) Mu ltiv ar ia te an al ys is Ch al m er s 11 (2 015 ), US A Cr os s-se ct io nal 42 0 ( no t spec ifi ed ) 14 .9 ( 9-22 ) Ba se ba ll: Al l le ve ls An y c ur re nt di sc om for t i n the shou ld er or e lb ow w hi le pit ch ing Shou ld er or e lb ow H ist or y o f i nj ur y 2. 46 (1 .59 -3 .7 9) * H ar ad a 5 (2 01 0) , Jap an Pr os pec tiv e coh or t 29 4 ( no t spec ifi ed ) 11 (9 -1 2) Ba se ba ll: yo ut h l ea gu e tea m s An y h ist or y of a n e pi so de of e lb ow p ai n dur in g t hr ow in g El bo w Ag e > 1 1 y ea rs Ag e < 1 1 y ea rs 2. 82 (1 .30 -6 .10 ) H ei gh t > 15 0 c m H ei gh t < 15 0 c m 2. 02 (1 .07 -3 .8 2) Po sit io n o f p itc he r O th er p os itio ns 4. 50 (2 .4 2-8.3 7) Tra in in g e ve ry d ay 1.9 6 ( 1.0 2-3. 79 ) Sh ou ld er e xt er nal ro ta tio n <1 30 ° Ex ter nal ro ta tio n >1 30 ° 1.9 8 ( 1.0 1-3. 87 ) M ax . s ho ul de r e xt er na l ro ta tion m usc le st re ng th > 80 N Ex ter nal ro ta tio n st re ng th < 80 N 4. 11 (1 .4 7-11 .5 5) M ax s ho ul de r i nt er na l r ot at io n m usc le st re ng th > 10 0N In ter nal ro ta tio n st re ng th < 10 0N 2. 04 ( 1.0 8-3.9 0) Ka ne ma tsu 9, ( 20 15 ), Jap an Cr os s-se ct io nal 20 55 ( no t spec ifi ed ) N ot spec ifi ed (9 -1 2) Ba se ba ll: re gio nal cha m pi on sh ip An y h ist or y o f an e pi so de o f sh oul de r p ain Shou ld er ≥ 1 y ea r o f b as eb al l e xp er ie nc e 1.4 4 ( 1.03 -2 .03 )
