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229
SYSTEMATIC REVIEW
DOI: 10.1590/1809-2950/17014825022018
229
Corresponding address: Fábio Hech Dominski – Rua Pascoal Simone, 358, Coqueiros – Florianópolis (SC), Brazil – ZIP Code 88080-350 – E-mail: fabio.dominski@udesc.br–
Telefone: (48) 3664-8677 – Finance source: Nothing to declare – Conflict of interests: Nothing to declare – Presentation: Aug. 9th, 2017 – Accepted for publication: May 24th, 2018.
Injury profile in CrossFit practitioners:
systematic review
Perl de lesões em praticantes de CrossFit: revisão sistemática
Perl de lesiones en los practicantes de CrossFit: revisión sistemática
Fábio Hech Dominski1, Thais Cristina Siqueira2, Thiago Teixeira Serafim3, Alexandro Andrade4
Study conducted in the Laboratory of Sport and Exercise Psychology (Lape) of the Santa Catarina State University (Udesc) –
Florianópolis (SC), Brazil.
1Laboratory of Sport and Exercise Psychology (LAPE) from the Center of Health and Sport Sciences (Cefid) of Santa Catarina State
University (Udesc) – Florianópolis (SC), Brazil.
2Department of Physical Therapy of the Center of Health and Sport Sciences(Cefid) of Santa Catarina State
University (Udesc) – Florianópolis (SC), Brazil.
3Laboratory of Sport and Exercise Psychology (Lape) of the Santa Catarina State University (Udesc) – Florianópolis (SC), Brazil.
4Graduate Program in Human Movement Sciences at the Laboratory of Sport and Exercise Psychology (LAPE) from the Center of
Health and Sport Sciences (Cefid) of Santa Catarina State University (Udesc) – Florianópolis (SC), Brazil.
ABSTRACT | CrossFit is a new form of physical training
that has become popular since its inception. This study
aimed to analyze the injury profile of CrossFit practitioners
through a systematic review. PRISMA recommendations
were applied to this systematic review. Electronic search
was performed in the databases CINAHL, SciELO, Science
Direct, SCOPUS, LILACS, PEDro, PubMed, SPORTDiscus
and Web of Science. The methodological quality of the
studies was assessed. Ten studies were selected. The
prevalence of injuries in CrossFit practitioners ranged
from 5 to 73.5%, and the overall injury incidence rate
per 1000 training hours ranged from 1.94 to 3.1 injuries.
The body region most aected by injuries was the
shoulders, followed by the back and the knees. Regarding
associated factors, the type of exercise performed and
CrossFit training time were related to injuries. Besides
that, sex was associated to the prevalence of injuries,
with men showing more injuries than women. Age was
not related to injury prevalence. It was concluded that the
most commonly aected body region among CrossFit
practitioners was the shoulders, predominantly in males
and with previous injuries, often obtained in other
modalities. In addition, CrossFit can be safely practiced
by individuals aged 18-69.
Keywords | Exercise; High-Intensity Interval Training;
Wounds and Injuries; Review.
RESUMO | O CrossFit se apresenta como um novo método
de treinamento físico que vem ganhando popularidade
desde sua criação. O objetivo deste estudo foi analisar
o perfil de lesões em praticantes de CrossFit por meio
de uma revisão sistemática da literatura. Utilizaram-se as
recomendações da Declaração PRISMA para condução
da revisão sistemática. A busca foi realizada nas bases
de dados CINAHL, SciELO, Science Direct, SCOPUS,
LILACS, PEDro, PubMed, SPORTDiscus e Web of Science.
Avaliou-se a qualidade metodológica dos estudos, entre
os quais dez foram considerados elegíveis. A prevalência
de lesões nos praticantes de CrossFit variou de 5 a
73,5%, e a taxa de lesão variou de 1,94 a 3,1 lesões a
cada 1.000 horas de treinamento. A região corporal mais
acometida por lesões nos estudos selecionados foram
os ombros, seguidos pelas costas e joelhos. Em relação
aos fatores associados às lesões, destacou-se o tipo de
exercício realizado e o tempo de prática de CrossFit. O
sexo apresentou associação com a prevalência de lesões:
estudos demonstraram que os homens apresentaram
maior número de lesões em relação às mulheres. A idade
esteve entre os fatores que não estiveram associados às
lesões. Conclui-se que os ombros são a região corporal
mais comumente acometida entre os praticantes de
CrossFit, em indivíduos do sexo masculino e com lesões
prévias, muitas vezes obtidas em outras modalidades.
Fisioter Pesqui. 2018;25(2):229-239
230
Constatou-se, ainda, que o CrossFit pode ser praticado com
segurança por indivíduos de 18 a 69 anos.
Descritores | Exercício; Treinamento Intervalado de Alta
Intensidade; Ferimentos e Lesões; Revisão.
RESUMEN | CrossFit es un nuevo método de entrenamiento
físico y ha ganado popularidad desde su creación. El objetivo
de este estudio fue analizar el perfil de lesiones en practicantes
de CrossFit a través de una revisión sistemática. La Declaración
PRISMA fue utilizada para la preparación de esta revisión. Se
realizó una búsqueda bibliográfica en las siguientes bases de
datos: CINAHL, SciELO, Science Direct, SCOPUS, LILACS, PEDro,
PubMed, SPORTDiscus y Web of Science. Se evaluó la calidad
metodológica de los estudios, entre los cuales diez estudios
fueron considerados elegibles. La prevalencia de lesiones en
los practicantes de CrossFit tuvo una variación del 5 al 73,5%,
y la tasa de lesiones de 1,94 a 3,1 lesiones a cada 1000 horas
de entrenamiento. La región corporal más lesionada fueran los
hombros, seguido por las espaldas y rodillas. En relación a los
factores asociados a las lesiones, se destacan el tipo de ejercicio
fue realizado y el tiempo de práctica del CrossFit. En relación
al género, los hombres presentaron más lesiones. La edad no
estuvo asociada a las lesiones. Se concluye que la región corporal
más comúnmente acometida entre los practicantes de CrossFit
fueron los hombros, en individuos masculinos y con lesiones
previas, muchas veces obtenidas en otras modalidades. Además,
el CrossFit puede ser practicado con seguridad por individuos de
18 a 69 años.
Palabras clave | Ejercicio; Entrenamiento de Intervalos de Alta
Intensidad; Heridas y Lesiones; Revisión.
INTRODUCTION
It is noteworthy that there is a fairly recent interest
of researchers and the general public in physical
activities in which high intensity is prevalent1. Studies
show that high intensity training provides more
benets to physical tness and health while having
shorter duration, when compared to traditional
training methods1,2.
us, CrossFit presents itself as a new method of
physical training that has gained popularity since its
creation and implementation at the beginning of the
new millennium3. It aims to promote physical tness
through the development of components such as aerobic
capacity, muscular strength and endurance, speed,
coordination, agility and balance4, through sports and
functional exercises, comprising weightlifting exercises,
gymnastic and aerobic conditioning movements, which
can be executed at high intensity5.
In the world, there are about 12,000 certied and
registered tness centers and gyms that oer CrossFit3;
of these, approximately 440 are in Brazil, involving
approximately 40,000 practitioners and athletes6.
Research shows a signicant growth in the number of
practitioners of this modality in various populations,
such as healthy or obese individuals and athletes, due
to its challenging and motivational nature7-9. Evidence
shows that about 5% of CrossFit practitioners present
a dependency relationship, which is signicantly
associated with the incidence/frequency of injuries4.
e American College of Sports Medicine (ACSM)
suggests potential benets of CrossFit, but also
highlights signicant injury risks in extreme
conditioning programs like the aforementioned10.
ese programs involve the execution of some exercises
that, if performed incorrectly or excessively, can cause
musculoskeletal injuries, ligament injuries, and even
rhabdomyolysis10. In this way, concerns over the
potential injury risk associated with the intense and
repetitive nature of CrossFit and the necessary technical
requirements for performing the exercises safely have
grown in academia and in the practice of modality11.
Gathering information from studies available in the
literature on injuries of CrossFit practitioners allows us
to get to know data related to the prevalence and rates
of injury by hours of training, most commonly injured
body regions, and injury-related factors, aiming to
develop and implement preventive actions in its practice,
considering the increase of the number of practitioners
and, consequently, of environments that allow for the
practice of CrossFit. In addition, a systematic review
with analysis of these aspects for clinical decision
making in the elds of medicine and physical therapy
is valuable. Since the currently published reviews on
CrossFit injuries12,13 were limited to investigating the
injury rate by comparing it with other types of physical
exercises and sports, no studies were found addressing
the various aspects these injuries have, such as rate and
prevalence, commonly aected body regions and related
factors, hence resulting in an injury prole14,15. us, the
Dominski et al. Injuries in CrossFit practitioners
231
objective of this study was to analyze the injury prole of
CrossFit practitioners through a systematic review of the
literature.
METHODOLOGY
is is a systematic review of the literature
following the recommended criteria of the PRISMA
Statement–Preferred Reporting Items for Systematic
Reviews and Meta-Analyses16.
Search Strategy
Representing a signicant part of global scientic
production, the search for studies was performed on the
electronic databases related to Sport and Physical Exercise
Sciences, and Physical erapy: CINAHL via EBSCO,
SciELO (Scientic Electronic Library Online), Science
Direct, SCOPUS (Elsevier), LILACS(Literatura Latino-
Americana e do Caribe em Ciências da Saúde), PEDro
(Physiotherapy Evidence Database), PubMed(National
Library of Medicine and National Institutes of Health),
SPORTDiscus via EBSCO, and Web of Science –
Coleção Principal (omson Reuters Scientic).
e search took place in May 2017 and ended
on 11 May of the same year. In order to include all
production conducted on the topic in the databases
selected, and because of the recent creation and
development of CrossFit, the only term used for article
search was “Crosst”, in the same way the study by
Meyer et al.13 was conducted.
e search in the database Web of Science was
performed in Core Collection, the basic search eld
with the term “Crosst”, the item Topic selected and
Timespan set as all years.
ELIGIBILITY CRITERIA
Only original articles about injuries with athletes
and practitioners of CrossFit were considered, including
studies with quantitative, qualitative or mixed approach,
with summaries and texts available in full online until
11 May 2017. No time limit was set. Review articles,
case studies, conference abstracts, editorials and letters
were excluded.
Eligibility of the studies occurred by means of the
PICOS criteria and are detailed in Table 1.
Table 1. Criteria for inclusion and exclusion of the studies selected
for review
Inclusion Exclusion
PParticipate Any individual
practitioner of CrossFit
Individuals practicing
other forms of physical
exercise
IIntervention CrossFit
Massages, manual
therapy, stretching,
alternative therapies,
weight training,
hiking or running,
High Intensity Interval
Training (HIIT)
CComparison
With healthy
individuals or not,
with groups of other
physical exercises, or
Control Group without
intervention
–
OOutcome Injuries, trauma –
SStudy
Randomized and non-
randomized controlled
study
Case studies, review,
review with
meta-analysis
Selection of studies and data extraction
e studies were selected by three reviewers
(FHD, TCS, TTS), independently. Initially, analysis
of the article titles identied through the search
strategy was conducted, followed by examination of
the abstracts. Subsequently, analysis of the full text
of the articles selected in the previous steps was
performed. Disagreements between reviewers were
resolved by consensus.
For determining injury prole in CrossFit,
data analysis was conducted while considering the
following categories: prevalence and type of injury,
body region aected by injury, injury rate by training
time and whether factors were related to injuries or
not.
Assessment of the methodological quality of the
studies
In order to assess the methodological quality
of the studies, the recommendations of STROBE
(Strengthening the Reporting of Observational
Studies in Epidemiology) were followed, by means
of the STROBE Statement – Checklist of items
that should be included in reports of cross-sectional
studies17,18. is checklist has 22 items that received
a score from 0 (does not meet) to 1 (meets), the
total score was obtained from the sum of the item
Fisioter Pesqui. 2018;25(2):229-239
232
scores and, according to the nal score of the study,
a classication in accordance with Mataratzis et al.19
was dened: a) when the study met more than 80%
of the criteria as established by STROBE, indicating
better quality of studies; b) – when 50% to 80% of
STROBE criteria were met; and c) when less than
50% of the criteria were met.
RESULTS
e search resulted in 684 entries. After duplicate
exclusion (n=75) and title reading, 100 articles were
selected for the abstract. In this step, other 79 were
excluded 79, with 21 left for full reading. Finally, 10
studies were part of the nal review (Figure 1).
INCLUSION ELIGIBILITY SCREENING IDENTIFICATION
Search Results (684)
CINAHL (14)
Lilacs (2)
PEDro (2)
PubMED (69)
SciELO (0)
ScienceDirect (80)
SportDiscus (284)
Web of Science (68)
Studies after removal of duplicates (609)
Excluded by title (509)
Selected for abstract Reading (100)
Excluded by the abstract (79)
Selected for complete text reading (21)
Studies included after
reading the references
(2)
Studies excluded by reading whole article (13)
- Does not concern injury (4)
- Does not concern CrossFit (4)
- Other study types (3)
- Complete text unavailable (2)
Studies included for analysis (10)
Figure 1. Flowchart of the selection process of the studies included
Dominski et al. Injuries in CrossFit practitioners
233
e sample size of the selected studies ranged from
34 to 1,393, totaling 3,307 research subjects, 2,244
being of male and 871 of female sex (192 subjects
did not have their sex reported). e subjects were
characterized as CrossFit practitioners in six studies,
athletes in three studies, and soldiers in one. e average
age of the research subjects ranged from 26.8 to 38.9
years, and the age group ranged from 18 to 69 years.
e prevalence of injuries in the studies ranged
from 5 to 73.5%. e rate of injuries every 1,000
hours of CrossFit training ranged from 1.94 to 3.1
injuries (Chart 1).
Chart 1. CrossFit injuries: Author, sample and main results related to injuries
Author
Sample Results – Injuries
n
Sex Age
average
(years)
Population Prevalence
(n/%) Type of injury Injury rate (every 1,000
hours of training)
Men Women
Grier et al.20 1393 1248 145 26.8 Soldiers 5% – –
Hak et al. 21 132 93 39 32.3 Athletes 97 (73.5%) – 3.10 injuries
Weisenthal et al.22 386 231 150 18 to
69 Practitioners 75 (19.4%) Inflammation, sprain and
dislocation –
Chachula, Cameron, Svoboda23 54 40 14 17 to
50 Practitioners 24 (44%) Joints –
Huynh et al.24 34 25 9 35.5 Practitioners 12 (35%) Rhabdomyolysis –
Sprey et al. 6566 323 243 31.4 Practitioners 176 (31%) – –
Summitt et al.25 187 – – – Practitioners 44 (23.7%) – 1.94 injuries
Aune, Powers26 247 139 108 38.9 Athletes 85 (34%) – 2.71 injuries
Montalvo et al.27 191 94 97 31 Athletes 50
(26.17%) More acute than chronic 2.3 injuries
Moran et al.3117 51 66 35 Practitioners – Acute and of Gradual start 2.10 injuries
Caption: (–): Not reported
Figure 2. Body regions aected by injuries in studies on CrossFit (number of studies per regions)
Fisioter Pesqui. 2018;25(2):229-239
234
e body region most aected by injuries in the
studies selected were the shoulders (7 studies). Back
and knees were injured regions in practitioners of
4 studies each, followed by the lumbar region in 3
studies, and arms/elbows in 2 studies. Body regions
like head/neck, wrists, thighs, legs and feet were cited
as injured regions in one study (Figure 2).
Several injury-related factors were observed
in CrossFit practitioners and athletes. e most
present factors within the studies were the type of
exercise performed, in 5 studies3,22-25, and the training
time of CrossFit, in 3 studies6,26,27. In addition, sex
presented relation to the prevalence of injuries,
where men presented a higher number of injuries in
relation to women, and the presence of prior injury
was associated with new injuries. In 5 studies, age
was among the factors not associated with injuries
(Chart2).
Chart 2. Results of studies on CrossFit in relation to factors associated and not associated with injuries
Author Factors associated
with injuries Results Factors not associated
with injuries
Grier et al.20
a) Sex and body
mass index
b) Smoking
a) Risk of injury greater for men with BMI classified as overweight or obese
b) Risk of injury greater in smokers compared to non-smokers. –
Weisenthal et al.22
a) Sex
b) Type of exercise
c) Supervised by
professional
a) Men presented more injuries than women (53 against 21)
b) The shoulder was more injured in gymnastic movements and the lumbar
was more injured in powerlifting movements
c) The rate of injury significantly decreased with the involvement of the
instructor
Age, participation time,
training session time,
training days per week
Chachula,
Cameron,
Svoboda23
a) Prior injury
b) Type of exercise
a) Practitioners with prior injury are 3.75 times more likely to suer an injury
related to CrossFit
b) Participants realize that exercises like deadlift and kettlebell swing
aggravate lumbar injuries, jumps intensify knee pain, and pain in the shoulders
and elbow are accentuated due to ring dips
Age
CrossFit experience
Participation in classes
with professional
supervision
Sprey et al.6a) Training time a) Practitioners of CrossFit since 6 months (35%) showed higher injury rate,
with 70% compared to practitioners with less training time Sex and age group
Summitt et al.25 a) Type of exercise a) Practitioners considered gymnastic exercises as the main cause of injury
(25 of 46 total injuries).
Age, number of resting
days
Aune and Powers26
a) Training time
b) Type of exercise
c) Equipment type
d) Prior Injury
b) Excessive eort
and inadequate
technique
a) The incidence rate of injury among athletes with less than 6 months of
experience was 2.5 times higher than that of athletes with more than 6
months of experience
b) Squat cleans, ring dips, overhead squats and push presses were more likely
to cause injury
c) Exercises performed with bars resulted in more injuries
d) Athletes with prior shoulder injury are 8.1 times more likely to injure the
shoulder compared to athletes with healthy shoulders
e) Athletes reported that 35% of injuries occurred due to overexertion and
20% due to improper technique in the execution of the exercises
–
Montalvo et al.27
a) Participation and
training time
b) Physical activity
aside from CrossFit
c) Stature
a) The injured athletes presented more participation time (in years) and
weekly time of CrossFit practice compared to non injured
b) Athletes with physical activity practice aside from CrossFit were 2.3 more
likely to injure themselves
c) Injured athletes presented greater stature compared to non-injured
Age, sex, size of CrossFit
class, number of trainers,
years of structured
physical activity,
and participation in
competitions
Moran et al.3a) Sex
b) Type of exercise
a) Highest rate of injury found in men who had injury in last 6 months
b) Weightlifting exercises were the most cited as cause of injury: squat,
deadlift, overhead press and Snatch.
–
Caption: (–): Not reported
Dominski et al. Injuries in CrossFit practitioners
235
Regarding to the assessment of methodological
quality according to the criteria of STROBE, adherence
to the criteria varied between 50% and 81.8%, the
majority of studies being classied as B and only one
study classied as A, having above 80% of the criteria
met (Table 2).
Table 2. Assessment of methodological quality of the studies included
STROBE criteria Title and
Abstract Introduction Methods Results Discussion Other
information
Total Score
(%) Classification
Studies
Grier20 0/1 1/2 4/9 4/5 3/4 0/1 12 (54.5%) B
Hak et al.21 1/1 1/2 4/9 5/5 4/4 0/1 15 (68.1) B
Weisenthal et al.22 1/1 2/2 7/9 4/5 4 /4 0/1 18 (81.8) A
Chachula, Cameron, Svoboda23 0/1 2/2 6/9 3.5/5 4/4 0/1 15.5 (70.4) B
Huynh et al.24 1/1 1/2 3/9 3/5 3/4 0/1 11(50) B
Sprey et al.61/1 2/2 6/9 4/5 4 /4 0/1 17 (77.2) B
Summitt et al.25 1/1 1/2 3/9 3/5 3/4 0/1 11 (50) B
Aune, Powers26 1/1 1.5/2 6.5/9 4.5/5 2/4 0/1 15.5 (70.4) B
Montalvo et al.27 0/1 2/2 6/9 4/5 3/4 0/1 13 (59) B
Moran et al.30/1 1/2 8/9 2/5 3/4 0/1 14 (63.6) B
DISCUSSION
is study aimed to analyze the injury prole of
CrossFit practitioners through a systematic review
of the literature. For determining injury prole in
CrossFit, data such as prevalence and type of injury,
body region aected, injury rate by training time, and
whether factors were related to injuries or not like sex,
age and type of exercise were analyzed and will be
further discussed in the following sections.
Injury prevalence
e prevalence of injuries was distributed unevenly
among studies, which can be explained by the large
amplitude in sample sizes, aside from dierences
between the populations analyzed and training
characteristics.
Although one of the studies showed high prevalence
of injuries with 73.5%21, this one was conducted
through questionnaire available in online forums, which
is a methodological limitation, as it is not known how
many individuals have seen the research and opted
not to respond. In addition, Hak et al.21 conducted the
study with practitioners of all CrossFit participation
levels; on the other hand, the prior training experience,
that is, the previous practice of the participants of the
research by Weisenthal et al.22 and Grier et al.20 may
have contributed to the lower prevalence of injuries
when compared to the study by Hak et al.21, but this
relationship is not clear in the literature yet.
Injury rate
When compared to other modalities of physical
exercise or sport, the injury rate of CrossFit is not
considered high. A rate of 3.1 injuries every 1,000 hours
of training as a maximum value found in the studies
was observed21. In sports, rates from 2.3 to 33 injuries
in running, 2.5 in handball, 5.4 in triathlon, 5.45 in
gymnastics, 9.6 in soccer and 26.7 in rugby, every 1,000
hours of training, were found28-33.
It is inferred that this result may occur due to the
absence of determinants such as physical contact and
practice of exercise on irregular soils, which were already
shown to be associated with injuries in sports34-36.
Associated factors
A higher injury rate was observed in males, a
result that may be related to the lower demand of
men for trainers compared to women with the aim
of being supervised. Evidence shows that women
consult their trainers for doubts and supervision more
when compared to men22. Publications on injuries
comparing men and women have also shown a higher
prevalence in males, in sports such as basketball, judo
and running37-39.
Fisioter Pesqui. 2018;25(2):229-239
236
Several populations have sought to practice CrossFit,
many already practicing other forms of physical exercise
or sport and, in some cases, this population is composed of
people with prior injuries. It was observed that this is an
important related factor, because individuals with previous
injuries are 3.75 times more likely to acquire them again in
CrossFit23, specically with regard to the shoulder, where it
was shown that athletes with prior injury are eight times
more likely to injure the shoulder compared to athletes
with healthy shoulders26. erefore, the need for attention
to the anamnesis of new practitioners in sites that oer
CrossFit practice is highlighted, in order to know prior
injuries and prevent the recurrence of these injuries.
e association between injury and training time
was shown to be not clear, as some studies have shown
that practitioners with longer training time suer more
injuries in relation to those with less time6,27. On the
other hand, a study found an incidence rate of injury
among athletes with less than six months of experience
to be 2.5 times greater than that of athletes with more
than six months of experience, which can be explained
by the lack of execution of the correct movements
technique26. Despite the training time and weekly
frequency being associated with greater experience in
the exercises, there is the increase in exposure of the
practitioner to repetitive movement, which increases
the chances of injury27. Furthermore, one of the features
present in the practice inside CrossFit gyms is the
establishment of personal records, especially in exercises
related to weightlifting, in which the individual seeks to
execute the movement with the greatest possible load.
is encourages practitioners to raise the load as they
increase their practice time, aiming to improve their
records, but also increasing the risk of injury. Hak et
al.21 suggest a focus on the proper execution technique,
being a more important feature than speed and number
of repetitions performed.
e fact that most studies found no association between
the presence of injuries and age/age group reinforces what
is proposed by Weisenthal et al.22, who claim that CrossFit
is a tness training program that can be practiced safely by
individuals of a wide age range – from 18 to 69 years, but
only if carried out in a safe environment.
Body regions aected and type of exercise
e shoulder was the joint most aected by injuries
due to CrossFit training. According to studies, this
result is related to the execution of some exercises that
have been considered harmful – such as overhead squat,
push press, kettlebell swing and snatch26 – because they
have a high range of motion of the shoulder complex, a
characteristic that can increase the risk of injury, since
movements above the shoulder joint lead to injury due
to the reduction of the subacromial space40.
e study by Weisenthal et al.22 showed that, for the
olympic gymnastics movements present in the modality,
there was signicant dierence between the body
regions that suered injury, the shoulder being the most
injured, corresponding to more than 41% of shoulder
injuries in the practitioners analyzed. e cause of this
type of injury is usually associated with a decrease in
the stabilization of the scapulothoracic joint. Scapular
dyskinesia aects the excursion movement of this joint,
overloading the glenohumeral joint41,42, which is usually
associated to muscle imbalance, mainly due to weakness
of the serratus anterior and lower trapezius bers43,44.
e study by Summit et al.25 showed that, among the
gymnastic movements that cause injury (25 out of 46)
reported by practitioners, there are kipping pull-up, ring
muscle-up, push-up and ring dips
In addition to the exercises derived from gymnastics,
the exercises specic to olympic weightlifting that
constitutes CrossFit, like overhead squat, require
the placement of the shoulder joint in positions of
extreme exion, abduction and internal rotation, which
increase the risk of injury45. Due to the high incidence
of shoulder injuries found in the studies, greater
caution is suggested regarding gymnastic exercises
and olympic weightlifting on the part of practitioners
and professionals who supervise the execution of these
movements, with a focus on factors such as overexertion
and improper technique, factors reported by athletes to
cause injuries in 35 and 20% of cases, respectively26.
Previously cited in the literature as a risk during the
practice of CrossFit10, cases of rhabdomyolysis were
reported in one related study24. According to Hak et al.21,
this may have occurred due to the inclusion of practitioners
of various tness levels, where rhabdomyolysis is to be
expected in those who exercise in extremely high levels
of intensity. Rhabdomyolysis is a condition not exclusive
of CrossFit, since other sports, if performed strenuously,
can also cause it. It usually occurs due to poor exercise
prescription or execution without adequate supervision46,
factor of which is also associated with injuries in
CrossFit, as veried in the study by Weisenthal et al.22,
where the injury rate was signicantly decreased with the
involvement of the instructor.
Dominski et al. Injuries in CrossFit practitioners
237
Lack of proper supervision and/or bad training
prescription can result in training components like volume
and inadequate load for the practitioner47, especially when
it comes to extreme conditioning program. is way, the
trainer must possess knowledge of the peak load of each
athlete in order to prevent injuries. Halson48 suggests
some variables that can be assessed to monitor the
training load. Variables such as frequency, time, training
intensity, eort, repetitions, volume, perceived exertion or
fatigue, technical analysis, among others, must be taken
into consideration. e monitoring of these variables is
important to prevent injuries, since performance should
not be the only way to verify whether training load is
suitable or not for the athlete48.
e epidemiological condition of injuries in some
sports and physical exercise modalities still has gaps,
lacking further investigation49. In this case, CrossFit
stands out, as it is a type of new physical training that has
shown signicant growth in recent years. Consequently,
the scientic literature on injuries in this modality is
also novel, so it is suggested that be performed research
on injuries analyzing practitioners and athletes after
exposure to CrossFit in the long term in future studies,
featuring prospective longitudinal studies, with better
methodological conditions and specic instruments.
All selected studies in the review met 50% or more
of the criteria dened by STROBE. Most of items not
met were related to the description of the methods,
particularly with respect to bias, sample size and
treatment of quantitative variables. Aside from that,
no studies reported other information such as funding.
Such ndings suggest the need for more detail in the
description present in the Methods section in future
studies, for better methodological quality.
e selected studies present limitations, as they
investigated the injuries of practitioners through
self-report, so the accuracy of some answers may have
been impaired, demonstrating the need for the use or
development and validation of specic instruments for
analyzing this population. In addition, most studies were
characterized as retrospective, that is, based on past data,
and few studies addressed the issue of the treatment used
for injuries, which can be a subject of future research.
Clinical implications
e extrapolation of the ndings of this study enables
professionals involved with CrossFit practitioners to
identify risk factors associated with injuries, in order to
act preemptively against them. Knowing the population,
most aected body regions and providing proper
supervision in the practice of the modality allows the
practitioner to be oriented correctly, minimizing the
risk of injury. Knowing that population is important
for the execution of physical and functional evaluations
with the modality practitioner. is can be done, for
example, with assessments on the factors mobility,
balance and neuromuscular control by tests such as Y
balance and step down50,51. Poor performance in those
tests shows the need for greater caution for these
practitioners.
CrossFit classes with little supervision and/or with
a high number of practitioners should also be avoided,
as the professional control over movements performed
incorrectly becomes more dicult. In addition, the
work leading up to the workout of the day (WOD),
such as warm ups and activities for developing a specic
skill must be performed.
CONCLUSION
It is concluded that the shoulders are the most
commonly aected body region, followed by the back
and knees, according to the studies analyzed. e
injuries were reported more frequently in males and with
previous injuries, often obtained in other modalities. In
most studies, it was not possible to observe relations
between age and the presence of injuries, characterizing
CrossFit as a physical training program that can be
practiced safely by individuals from 18 to 69 years.
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