Study Characteristics:
In 13 included studies we detected three different study designs: Retrospective cross-sectional study(12–14, 16–18) (n = 6), retrospective case-control study(19) (n = 1), prospective cohort studies(5, 6, 15, 20–22) (n = 6).
Furthermore, given the differences in rules, bout design and injury prevalence, dividing the studies in cohorts of amateur(6, 12, 13, 15, 16, 20) (n = 6) and professional(14, 17–19, 21, 22) (n = 6) boxers (with one study presenting results for both cohorts(5)) seemed reasonable.
Sample sizes ranged from 16 to 11,173 included athletes (median = 105), with 5 studies(5, 6, 20–22) including small samples of < 100 athletes, 4 studies(15, 17–19) including medium samples of 100-1,000 athletes and two studies(13, 14) including > 1,000 athletes. Most of the included studies displayed cohorts of male boxers with 4 studies including only males(6, 20–22), 3 studies with at least 90% males(5, 17, 19), one study including 70% males(18), one study including only females(13), and 3 studies not giving any gender characteristics(12, 14, 16) (considering however, that these studies have been published before 2000 and females have not been allowed at the Olympic games until 2012, it can be assumed that most cohorts were male). One study reported on a mixed cohort of different combat sports with boxing as a subgroup(22), while the rest of the included study cohorts were boxers only.
In terms of injury definition, the majority of studies(6, 15, 18, 21, 22) (n = 5) used “time loss” (events preventing the athletes from competing or training) as their main criteria, and 2 studies(12, 17) required “medical attention” (athletes sought out a physician or hospital) as their definition for injury. One study(5) used a combination of both definitions, and in 5 cases(13, 14, 16, 19, 20) injury was not defined. Data collection periods ranged from 2 months to 14.5 years (median = 8 months for prospective studies and median = 84 months for retrospective studies). Seven studies collected combined data on injuries sustained in competition and training(5, 6, 15, 18, 20–22), 3 studies presented only competition data(13, 17, 19) and 3 studies gave no information on this part(12, 14, 16).
Further details on study characteristics can be found in Tables 1 and 2.
Table 1
Study characteristics for amateur cohorts
Author
|
Journal
|
Study design
|
Data collection method
|
Data collection period
|
Statistics
|
N
|
Gender
|
Age (mean)
|
DoI
|
Oelman 1983(12)
|
J R Arm Med Corps
|
RCS
|
Screening of hospital admissions
|
12 years
|
descriptive analysis
|
5700
|
?
|
22,12
|
MA
|
Timm 1993(16)
|
J Athl Train
|
RCS
|
retrospective analysis of standard medical report forms used by the per- manent and voluntary staff at the USOTC
|
14.5 years
|
χ2 tests
|
?
|
?
|
?
|
?
|
Porter 1996(15)
|
Clin J Sport Med
|
PCS
|
Injuries recorded during competition + self reported injuries during training
|
5 months
|
descriptive analysis
|
281
|
?
|
?
|
TL
|
Zazryn 2006(5)
|
Br J Sports Med
|
PCS
|
Self reported survey initially and assessment tool used by trainers and fight doctors assessment tool
|
12 months
|
χ2 and t tests
|
33
|
3 F
30 M
|
23,7
|
TL + MA
|
Bianco 2009(13)
|
Br J Sports Med
|
RCS
|
Medical examinations at bouts before and after competition
|
6 years
|
?
|
2800
|
100% F
|
?
|
?
|
Oke 2012(20)
|
Glo Adv Res J of Med and Med Sci
|
PCS
|
Injury documentation during training camp by medical team
|
4 months
|
descriptive analysis
|
29
|
100% M
|
22.50 ± 2.72
|
?
|
Loosemore 2015(6)
|
Br J Sports Med
|
PCS
|
prospective recording by GB medical team using a modified Orchard Sports Injury Classification System
|
5 years
|
χ2-tests, Z-scores and multiple regression analysis
|
66
|
100% M
|
22.0 ± 2.5
|
TL
|
Abbreviations:
RCS = retrospective cohort study, RCS = retrospective cross-sectional study, PCS = prospective cohort study, RCCS = retrospective case control study; DoI = definition of injury, MA = medical attention, TL = time loss; ? = information not given; M = males, F = females
|
Table 2
Study characteristics for professional cohorts
Author
|
Journal
|
Study design
|
Data collection method
|
Data collection period
|
Statistics
|
N
|
Gender
|
Age (mean)
|
DoI
|
McCown 1959(14)
|
Am J Surg
|
RCS
|
Injuries detected by the Commission and Medical Advisory Board
|
7 years
|
?
|
11173
|
?
|
?
|
?
|
Bledsoe 2005(19)
|
Southern Med J
|
RCCS
|
Clinical report of the physician at ringside
|
1.5 years
|
Logistic regression analysis for risk of injury calculation
|
688
|
92.2% M
|
?
|
?
|
Zazryn 2006(5)
|
Br J Sports Med
|
PCS
|
Self reported survey initially and assessment tool used by trainers and fight doctors
|
12 months
|
χ2 and t tests
|
14
|
F: 1
M: 14
|
31,8
|
TL + MA
|
Zazryn
2009(17)16
|
Clin J Sports Med
|
RCS
|
fight statistics database
|
8.5 years
|
descriptive analysis, univariate and multi-variate logistic regressions
|
545
|
98,3% M
9 F
536 M
|
27.9 (range 18.1–43.6)
|
MA
|
Siewe 2014(21)
|
Orthopedics and Biomechanics
|
PCS
|
questionnaire once a month
|
1 year
|
χ2−test, descriptive analysis
|
44
|
100% M
|
20.2
± 7.86
|
TL
|
Noh 2015(22)
|
J Phys Ther Sci
|
PCS
|
Injury questionnaire filled out by athletes under the supervision of a re- searcher
|
2 months
|
Student’s t-test, χ2 test and Fisher’s exact test
|
16
|
100% M
|
19.4 ± 0.3
|
TL
|
Kumar 2015(18)
|
IOSR J Sports Phys Ed
|
RCS
|
modified nordic musculoskelettal questionnaire
|
1 year
|
descriptive analysis
|
105
|
73 M
32 F
|
M: 16.26 ± 3.13;
F: 18.38
± 4.69
|
TL
|
Abbreviations:
RCS = retrospective cohort study, RCS = retrospective cross-sectional study, PCS = prospective cohort study, RCCS = retrospective case control study; DoI = definition of injury, MA = medical attention, TL = time loss; ? = information not given; M = males, F = females
|
Quality Assessment:
Given that publication dates of all included studies ranged from 1959 to 2015, a wide range of methodological quality was to be expected. High variability in study design and risk of bias led to considerable problems in applying quality assessment tools. Applying one tool and rating the included studies accordingly was deemed insufficient to guarantee that all methodological aspects were weighted in accordance with the underlying study design and methodology. Out of all the items assessed in the STROBE statement, we therefore chose to depict a sample of key quality features below to be considered in the further assessment of study outcomes. All further details and ratings concerning the quality assessment can be found in table 8 in the appendix section.
Participants:
Eligibility criteria for patient inclusion and the selection were present in most of the included studies, 11 studies(5, 6, 13, 15–22) therefore fulfill this criterion in its most basic form. Two older studies give no information on patient selection at all(12, 14). One study, which reports on injury prevalence in a cohort of boxers, is missing a total number of participants(16). Another study(22) is offering relative numbers that are not adding up in their tables. Also, only 3 studies(6, 15, 21) offered information on how drop-outs were handled (however, one needs to bear in mind that drop-out rates have a bigger impact on outcomes in prospective cohort studies than they have on retrospective cross-sectional studies).
Variables:
“Injury”, being the variable which all the included studies claim to assess, needs to be defined a priori. Therefore, all the studies having failed to include a definition of injury(13, 14, 16, 19, 20) were graded as not having fulfilled this criterion. Four studies used a questionnaire to gather information on injury prevalence(5, 15, 21, 22), one study however failed to report their response rate(22). Response rates will be discussed in the results section for each study, respectively.
Reported risk of bias:
A detailed description on detected bias is following in the “risk of bias” section. However, in the course of quality assessment, it also needs to be stated that authors addressed possible bias in only 4/13 included studies(5, 16–18).
Statistical analyses:
To report injury numbers and display them correctly, authors ought to define how they reached those numbers and what kind of calculations they used. Correct display of all calculated measures (including CI and SDs) is the basis for further evaluation and pooling of data. Four studies(12–15) give no information on the statistical measures they used, and only 3 studies give confidence intervals for the injury numbers(5) or statistical models(17, 19) presented. Two studies offer standard error values(15) or standard deviation, median and range(21) for exposure rates, but not for injury data. Two studies presented Chi-square tests with p-values(16) and/or Z scores(6) to compare injury locations.
Population characteristics:
Basic demographic information for the included sample is presented in the majority of included studies(5, 6, 15, 17–22), with one study also including technical information and medical history(13). However, 3 studies give no description of study participants except that they were boxers (12, 14, 16). Following basic demographic characteristics, information on exposure is highly relevant, especially in all the longitudinal cohort studies included. However, only 3 studies(5, 6, 21) offered information on training or competition exposure within this period.
Numerous potential confounders can be identified, some of which are discussed in 8/13 studies(5, 6, 12, 15–17, 19, 21). Most of these confounders concern injury prevalence (i.e. age, bouts/year, preexisting injury, sparring vs. bouts, protection gear), sometimes also study design, injury documenting measures and population are discussed as influencing factors.
Generalizability:
Generalizability is discussed only in 5 studies(5, 6, 12, 13, 16) and is considered high for 7 studies(5, 6, 15–17, 19, 21), and low for the rest, given the missing information on study participants (“population at risk”), exposure and possible confounders.
Risk of Bias:
Risk of bias sometimes correlates with the general quality of the study but is also a factor that affects analysis of outcomes on its own. Specific bias that readers need to be aware of are for example detection bias in those studies that do not declare a definition of injury(13, 15, 16, 19, 20), confounding bias in all included studies which mix training and competition data(12, 14, 16, 18, 20, 22) or recall bias in all retrospective studies relying on the participants’ memory(13, 18, 22).
Risk of bias was assessed using a modified Downs&Black’s questionnaire9. Applying the same questionnaire for all included studies again proved difficult. According to study design, different biases need to be addressed and not every item in the questionnaire works for every study. Items 8, 14, 15, 19 and 21–24 were not used at all, as they can be applied for intervention studies only. As some of the items (items 9, 11, 12, 16, 17 and 26) could only be applied for prospective longitudinal studies, risk of bias assessment will be presented separately for retrospective and prospective studies (see Tables 3 and 4).
Table 3
Risk of bias assessment for prospective studies
Item
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
9
|
10
|
11
|
12
|
13
|
16
|
17
|
18
|
20
|
25
|
26
|
27
|
total
|
Porter 1996(15)
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
0*
|
1
|
0
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
17
|
Zazryn 2006(5)
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
0*
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
0
|
17
|
Oke 2012(20)
|
1
|
1
|
1
|
1
|
0
|
1
|
1
|
0
|
0
|
0
|
1
|
1
|
1
|
1
|
1
|
0
|
1
|
0
|
0
|
12
|
Siewe 2014(21)
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
0
|
1
|
1
|
1
|
1
|
1
|
1
|
0
|
0
|
16
|
Loosemore 2015(6)
|
0
|
1
|
0
|
1
|
1
|
1
|
1
|
1
|
0
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
0
|
15
|
Noh 2015(22)
|
1
|
1
|
1
|
0
|
0
|
0
|
1
|
0
|
1
|
1
|
0
|
1
|
1
|
1
|
1
|
1
|
1
|
0
|
0
|
12
|
* descriptive study, therefore unable to determine
|
Table 4
Risk of bias assessment for retrospective studies
Item
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
9
|
10
|
11
|
12
|
13
|
16
|
17
|
18
|
20
|
25
|
26
|
27
|
total
|
McCown 1959(14)
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0*
|
0
|
0
|
1
|
0
|
0
|
0
|
0
|
0
|
0
|
1
|
2
|
Oelman 1983(12)
|
0
|
1
|
0
|
0
|
0
|
1
|
0
|
0
|
0*
|
0
|
0
|
1
|
0
|
0
|
1
|
0
|
0
|
0
|
1
|
5
|
Timm 1993(16)
|
1
|
1
|
0
|
0
|
0
|
1
|
0
|
0
|
1
|
0
|
0
|
1
|
0
|
0
|
1
|
1
|
0
|
0
|
0°
|
7
|
Bledsoe 2005(19)
|
1
|
1
|
1
|
1
|
0
|
1
|
1
|
0
|
1
|
0
|
0
|
1
|
0
|
0
|
1
|
0
|
1
|
0
|
0
|
10
|
Bianco 2009(13)
|
1
|
0
|
0
|
1
|
0
|
1
|
0
|
0
|
0*
|
0
|
0
|
1
|
0
|
0
|
1
|
0
|
0
|
0
|
1
|
6
|
Zazryn 2009(17)
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
0
|
0
|
0
|
0
|
1
|
0
|
0
|
1
|
1
|
1
|
0
|
1
|
12
|
Kumar 2015(18)
|
1
|
1
|
1
|
0
|
0
|
1
|
1
|
0
|
0*
|
0
|
0
|
1
|
0
|
0
|
1
|
1
|
0
|
0
|
0
|
8
|
* descriptive study, therefore unable to determine
° missing N, therefore unable to determine
Items not applicable for retrospective studies
|
By applying both STROBE quality assessment scores and Downs&Black’s risk of bias scores, we evaluated methodological quality of all included studies to determine how to interpret the outcome findings and whether to integrate them into further analyses. Figure 2 shows a scatter plot of combined STROBE quality assessment scores and Downs&Black’s risk of bias scores for all included studies.
In amateur cohorts (cohort 1) studies 1 (Oelman et al.(12)) and 5 (Bianco et al.(13)), and in professional cohorts (cohort 2) study 8 (McCown et al.(14)), can be easily identified as outliers, all three having an exceptionally low combined quality assessment score and risk of bias score with combined values of 15, 22 and 8 respectively compared to a mean combined score of 28 with a SD of 6.55 for all included studies (see Table 5 below). They were therefore not included in further statistical analyses.
Table 5
Descriptive statistics for STROBE quality assessment scores and Downs&Black's risk of bias scores
|
N
|
Minimum
|
Maximum
|
Mean
|
SD
|
Combined
|
13
|
15
|
39
|
28.00
|
6.545
|
Downs&Black
|
13
|
5
|
17
|
11.46
|
4.095
|
STROBE
|
13
|
6
|
22
|
16.54
|
4.409
|
Data analysis (Outcome):
Professionals
Table 6 presents the extracted outcome data of all the included studies on professional athletes with a detailed description following below.
The overall proportion of shoulder injuries among all detected injuries in professional boxing cohorts was 4% [2%; 8%],with the absolute frequency of shoulder injuries ranging from 1 to 10 injuries in the individual studies (see Figure 3). The heterogeneity index I2 was 69%.
Table 6
Outcome data for professional cohorts
Author
|
Data collection period
|
N
|
Competition exposure
|
Number of shoulder Injuries
|
%
|
Number of other Injuries
|
Injury rates
|
McCown 1959(14)
|
7 years
|
11173
|
not given
|
4 anterior shoulder dislocations
|
0.4
|
1010 lacerations or contusions
|
not given
|
Bledsoe 2005(19)
|
1.5 years
|
524 bouts, 688 boxers
|
not given
|
shoulder injuries: 6, shoulder and elbow: 1
|
3.59
|
195 injuries
|
17.1 per 100 boxing-matches or 3.4 per 100 boxer-rounds
|
Zazryn 2006(5)
|
12 months
|
14
|
mean 2.7; range 1.0–5.0
|
1 injury in training: shoulder inflammation
|
8.33
|
8 (comp.)
4 (training)
|
4.4/1000 h overall
1081,1/1000h (comp.)
1,7/1000h (training)
|
Zazryn 2009(17)16
|
8.5 years
|
545 boxers
907 bouts
|
not given
|
1 shoulder injury (strain)
|
0.47
|
214 injuries in total
|
23.6/100 fights:
|
Siewe 2014(21)
|
1 year
|
44
|
2.75 bouts per boxer/year
|
9 shoulder injuries (3 contusions, 3 strains, 2 impingement syndromes, 1 laceration)
|
4.69
|
192 injuries in total
67 in competition
125 in training
|
12.8/1000 h of training
|
Noh 2015(22)
|
2 months
|
16
|
not given
|
10 shoulder injuries
|
10.1
|
99 injuries in total
|
not given
|
Kumar 2015(18)
|
1 year
|
105
|
not given
|
3 shoulder injuries
|
6.25
|
48 injuries in total
|
1-year prevalence rate of 46%
|
As boxing dates back to 1904 as an Olympic sport, early medical records on injury epidemiology can be found within the literature. Already in 1959, McCown et al.(14) published data on boxing injuries in professional boxers, which they had gathered in the first seven years following implementation of the first Medical Advisory Board for boxing in the United States. Although details on cohort characteristics (age, competition exposure) and data collection methods (injury definition, injury recording), as well as information on statistical analyses are missing, their retrospective cross-sectional study included an astonishing sample of 11173 boxers. Besides, 1010 injuries to soft tissue resulting from trauma, 4 dislocations of the shoulder joint were mentioned.
In 2005, Bledsoe et al.(19) conducted an epidemiological study examining data from 524 professional boxing matches in the state of Nevada over a period of 1.5 years, using a retrospective case-control design including 688 participating boxers. The injured athletes were serving as cases and the healthy ones as controls. Although they obtained data on epidemiological characteristics (sex, age, weight) to perform injury risk calculations, no descriptive statistics on cohort characteristics (i.e. mean age) are offered. Injuries, as detected from the physician at ringside, are displayed in absolute and relative numbers with 6 injuries to the shoulder (3.16%) and 1 injury to the shoulder and elbow (0.53%) mentioned, without further specification on pathologies or injury definition.
In 2006, Zazryn et al.(5) published a prospective cohort study of 14 professional and 33 amateur boxers in Victoria, Australia, who were followed up monthly for a period of 12 months. Notably, the authors stated a response rate of 19% for amateurs and 25% for professionals. Providing a detailed description of data acquisition and cohort characteristics, they report an overall injury rate of 2.0 per 1000 hours of boxing (1.0/1000h in amateurs and 4.4/1000h in professionals). Being one of the few studies to differentiate between training and competition in their data analysis, they found injury rates to be a lot higher in bouts than in training (1081.1–1221.4 injuries per 1000 bout hours compared to 0.5–1.7 injuries per 1000 hours of training). While competition exposure is given as 2.7 bouts for professionals (range 1.0–5.0) and 3.6 bouts for amateurs (range 1.0–10.0), professionals are listed to have a higher total bout exposure in hours (7.4 for professionals and 3.3 for amateur athletes). Injury rates per 100 fights are also listed for amateurs and professionals separately (25 for amateurs compared to 33.3 for professionals). In professional athletes, they reported 5 shoulder injuries sustained in training, with one being listed as shoulder inflammation, but no shoulder injuries in amateurs.
While all of the other studies contain samples of mostly male athletes, Bianco et al.(13) reported on 2800 female amateur and professional boxers in Italy over a period of 6 years. While they give a lot of technical information and background on data acquisition, as well as prevalence for pathologies of the breast, urogenital tract and nervous system, further demographic information as well as injury rates are not listed. All listed injuries were detected in medical examinations after competition with 11 cases of contusion to the upper limb (hand, elbow, or shoulder) in amateurs, but none in professionals. Further specification on pathologies or injury definition are not given, also the data is limited to competition injuries. Therefore, there is no information on competition exposure.
Also in 2009, Zazryn et al.(17) analyzed 907 professional boxing bouts held in the past 8.5 years in the state of Victoria, including competition data only with injury being defined as “any injury reported to or by a ringside physician after bout participation”. In 545 athletes, they found 214 injuries and calculated an injury rate of 23.6 per 100 fights, or 60.7 per 100 when fights were stopped because of knockouts without further medical specification. Out of 17 upper extremity injuries, one shoulder injury was listed.
In a prospective cohort study published 2014, Siewe et al.(21) followed a sample of 44 professional athletes for one year with monthly questionnaires reporting injury occurrence (injury being defined as “an event causing interruption in training or competition”) with a response rate of 100%. They documented 67 competition injuries and 125 training injuries and found an overall injury rate of 12.8 per 1000 hours of boxing. On average, each boxer was found to compete in 2.75 bouts/year. Out of 47 upper extremity injuries, 9 shoulder injuries were documented with 3 contusions, 3 strains, 2 impingement syndromes and 1 laceration.
In a prospective cohort study, Noh et al.(22) followed 189 collegiate athletes of several combat sports, including judo, ssireum, wrestling, kendo, and taekwondo in addition to boxing (16 athletes) over a period of 2 months. They documented injuries using an injury questionnaire that was filled out by the athletes under the supervision of a group researcher and included information on injury type, location and mechanism/ surrounding factors. Injury is defined as bodily damage that interfered with competition or training. All athletes, except for one kendo fighter, experienced an injury during the observed time interval, but unfortunately no overall count of injuries per discipline or mean injury rate per athlete were described. The injury data were only presented in crosstabs of injury type and injury region with numbers not adding up correctly. When counting together all the listed boxing injuries within both categories, they sum up to 71 injuries categorized for injury types, in contrast to 99 injuries that can be counted when injuries are categorized in injury region. In addition to 13 head, 8 elbow, 16 wrist, 17 hands and fingers, 11 knee, 14 ankle, 1 toe, they also report 10 shoulder injuries in boxers, without further specification on injury mechanism or underlying pathology. This study focused more on comparison between combat sports, however absolute numbers of injuries are missing from tables and relative percentages are unclear, therefore making an injury rate comparison impossible.
Using the modified Nordic Musculoskeletal Injury Questionnaire, Kumar et al.(18) retrospectively collected data on injury rates within one year in 105 boxers, fighting at least at district level at different training sites in India. At a mean age of 16 for males and 18 for females, athletes in this study were younger than in any other study. Out of 48 injured athletes, 3 (6.25%) reported shoulder injuries that led to consultation of a doctor or physiotherapist. The study group also reported a higher rate of shoulder injuries in females than in males. However, the group size was clearly not balanced, and no information on statistical calculations was provided.
Amateurs:
In amateur boxing cohorts, the overall proportion of shoulder injuries among all detected injuries was 9% [6%; 12%] ,with the absolute frequency of shoulder injuries ranging from 0 to 86 injuries in the individual studies (see Figure 4). The heterogeneity index I2 was equal to 52%.
Table 7 depicts outcome data for all included studies of amateur cohorts. A detailed description of studies is following below.
Table 7
Outcome data for amateur cohorts
Author
|
Data collection period
|
N
|
Competition exposure
|
Number of shoulder Injuries
|
%
|
Number of other Injuries
|
Injury rates
|
Oelman 1983(12)
|
12 years
|
5700 (calc.)
|
not given
|
9 cases of dislocated shoulders (15.3 % of upper extremity injuries)
|
2.06
|
437 injuries
|
1/ 9000 man hours of boxing (calc.)
|
Timm 1993(16)
|
14.5 years
|
not given
|
not given
|
86 shoulder injuries
|
7.05
|
1219 injuries
|
not given
|
Porter 1996(15)
|
5 months
|
281 (comp.) 147 (training)
|
not given
|
4 shoulder injuries during training, 0 during competition
|
4.3
|
93 injuries in total
64 (comp.)
29 (training)
|
920/1000h of comp.
0.7 /boxer/year (comp.) 0.69/boxer/year (training)
|
Zazryn 2006(5)
|
12 months
|
33
|
mean 3.6; range 1.0–10.0
|
0
|
-
|
4 training injuries
4 competition injuries
|
1.0/1000h overall
1221,4/1000h (comp.)
0.5/1000h (training)
|
Massi-miliano 2009(13)
|
6 years
|
2800
|
not given
|
11 injuries of upper limbs (hand, wrist and/or shoulder)
|
-
|
51 injuries
|
not given
|
Oke 2012(20)
|
4 months
|
29
|
not given
|
17 strain/tendonitis of the shoulder
|
15
|
113 in total
|
3.9/athlete
|
Loose-more 2015(6)
|
5 years
|
66
|
mean 96.6 min per participant (range 2-356min)
|
21 shoulder injuries, days lost: 21.2
|
7.07
|
297 injuries in total
88 (comp.)
209 (training)
|
828/1000h of comp.
7.4/athlete
|
In a retrospective cross-sectional study, Oelman et al.(12) screened hospital records for admittance of Army personnel with boxing injuries over a period of 12 years, and found 9 cases of shoulder dislocations out of 437 total injuries With an estimated total of 59 hours of boxing per year, the overall injury rate was calculated as 1 per 9,000 man-hours of boxing. But there is no further information on competition exposure or injury mechanism.
Timm et al.(16) performed a retrospective analysis of standard medical report forms used by the staff at the United States Olympic Training Center staff over a period of 14.5 years. Sadly, there are no numbers on total participants or group characteristics (i.e. age or competition expose), or definition of injury. It was noted that training was made up mostly of sparring with less competitive elements, and a total number of 1,219 injuries were reported including 86 shoulder injuries.
Porter at al.(15) prospectively gathered data on injuries sustained by a cohort of 281 amateur boxers in Ireland over a period of 5 months, including injuries recorded during competition and self-reported injuries during training. Defining injury as an event that would stop the athlete from competing or training, they found 4 shoulder injuries during training out of 29 injuries in total, and none during competition. Interestingly, shoulder injuries had the highest average number of missed training days (14.2), and all four mentioned shoulder injuries were reported to be of the "predominantly chronic impingement type related to repeated punching activities". After all participants, who did not send back their questionnaires, were excluded from the study, a response rate of 100% was assumed.
Oke et al.(20) assessed all injuries that were sustained by 29 amateur boxers during 4 months of training camp. With 113 injuries in total, an injury rate of 3.9 per boxer was calculated. 17 shoulder injuries were described and further classified as “strain/tendonitis”. Only one friendly international boxing competition seemed to have taken place during the study period, but there is no further specification on competition exposure. The authors differentiate between 69% of “acute on chronic injuries” and 31% of “chronic injuries”. However, there is no indication as to how these categories were defined. It is also not clear, whether all athletes finished the camp or if there were any dropouts.
Prospectively following all male boxers on the British boxing squad, Loosemore et al.(6) recorded any injuries (“any musculoskeletal condition that prevented the boxer from participating in either training or competition for > 24 h”) that occurred during a 5 year period using a modified Orchard Sports Injury Classification System. In total, 297 injuries were sustained by the 66 athletes included, with 70% occurring in training and 30% in competition. 21 shoulder injuries were reported with a mean time loss of 21.1 days. The overall occurrence of new injuries was found to be significantly higher than it was for recurring injuries.