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Injury Rate and Patterns Among CrossFit Athletes


Abstract and Figures

Background: CrossFit is a type of competitive exercise program that has gained widespread recognition. To date, there have been no studies that have formally examined injury rates among CrossFit participants or factors that may contribute to injury rates. Purpose: To establish an injury rate among CrossFit participants and to identify trends and associations between injury rates and demographic categories, gym characteristics, and athletic abilities among CrossFit participants. Study Design: Descriptive epidemiology study. Methods: A survey was conducted, based on validated epidemiologic injury surveillance methods, to identify patterns of injury among CrossFit participants. It was sent to CrossFit gyms in Rochester, New York; New York City, New York; and Philadelphia, Pennsylvania, and made available via a posting on the main CrossFit website. Participants were encouraged to distribute it further, and as such, there were responses from a wide geographical location. Inclusion criteria included participating in CrossFit training at a CrossFit gym in the United States. Data were collected from October 2012 to February 2013. Data analysis was performed using Fisher exact tests and chi-square tests. Results: A total of 486 CrossFit participants completed the survey, and 386 met the inclusion criteria. The overall injury rate was determined to be 19.4% (75/386). Males (53/231) were injured more frequently than females (21/150; P = .03). Across all exercises, injury rates were significantly different (P < .001), with shoulder (21/84), low back (12/84), and knee (11/84) being the most commonly injured overall. The shoulder was most commonly injured in gymnastic movements, and the low back was most commonly injured in power lifting movements. Most participants did not report prior injury (72/89; P < .001) or discomfort in the area (58/88; P < .001). Last, the injury rate was significantly decreased with trainer involvement (P = .028). Conclusion: The injury rate in CrossFit was approximately 20%. Males were more likely to sustain an injury than females. The involvement of trainers in coaching participants on their form and guiding them through the workout correlates with a decreased injury rate. The shoulder and lower back were the most commonly injured in gymnastic and power lifting movements, respectively. Participants reported primarily acute and fairly mild injuries.
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Injury Rate and Patterns
Among CrossFit Athletes
Benjamin M. Weisenthal,* BA, Christopher A. Beck,
MA, PhD, Michael D. Maloney,
Kenneth E. DeHaven,
MD, and Brian D. Giordano,
Investigation performed at the University of Rochester School of Medicine and Dentistry,
Rochester, New York, USA
Background: CrossFit is a type of competitive exercise program that has gained widespread recognition. To date, there have been
no studies that have formally examined injury rates among CrossFit participants or factors that may contribute to injury rates.
Purpose: To establish an injury rate among CrossFit participants and to identify trends and associations between injury rates and
demographic categories, gym characteristics, and athletic abilities among CrossFit participants.
Study Design: Descriptive epidemiology study.
Methods: A survey was conducted, based on validated epidemiologic injury surveillance methods, to identify patterns of injury
among CrossFit participants. It was sent to CrossFit gyms in Rochester, New York; New York City, New York; and Philadelphia,
Pennsylvania, and made available via a posting on the main CrossFit website. Participants were encouraged to distribute it further,
and as such, there were responses from a wide geographical location. Inclusion criteria included participating in CrossFit training at
a CrossFit gym in the United States. Data were collected from October 2012 to February 2013. Data analysis was performed using
Fisher exact tests and chi-square tests.
Results: A total of 486 CrossFit participants completed the survey, and 386 met the inclusion criteria. The overall injury rate was
determined to be 19.4% (75/386). Males (53/231) were injured more frequently than females (21/150; P ¼ .03). Across all exercises,
injury rates were significantly different (P < .001), with shoulder (21/84), low back (12/84), and knee (11/84) being the most commonly
injured overall. The shoulder was most commonly injured in gymnastic movements, and the low back was most commonly injured in
power lifting movements. Most participants did not report prior injury (72/89; P < .001) or discomfort in the area (58/88; P < .001). Last,
the injury rate was significantly decreased with trainer involvement (P ¼ .028).
Conclusion: The injury rate in CrossFit was approximately 20%. Males were more likely to sustain an injury than females. The
involvement of trainers in coaching participants on their form and guiding them through the workout correlates with a decreased
injury rate. The shoulder and lower back were the most commonly injured in gymnastic and power lifting movements, respectively.
Participants reported primarily acute and fairly mild injuries.
Keywords: competitive exercise; CrossFit; Olympic lifting; power lifting; injury rate; cross-sectional pilot study
CrossFit is a conditioning program that has gained wide-
spread attention for its focus on successive ballistic
motions that build strength and endurance. It is charac-
terized by workouts that use a wide variety of exercises,
ranging from running and rowing to Olympic lifting
(snatch, clean, and jerk), power lifting (s quat, deadlift,
press/push press, bench press), and gymnastic movements
(pull-ups, toes-to -bar, knees-to-elbo ws, lunges, muscl e-
ups, burpees, dips, gluteus-hamstring developer sit-ups,
push-ups, rope climbs, handstand push-ups, pistols).
These exercises are often combined into high-intensity
workouts that are performed in rapid, successive repeti -
tion, with limited or no recovery time. It has been adopted
in both military and civilian populations with widespread
anecdotal reports of impressive fitness gains.
These gains are consistent with existing literature that
supports the contention that high-intensity, single modal
Address correspondence to Brian D. Giordano, MD, University of
Rochester School of Medicine and Dentistry, University of Rochester
Medical Center, 601 Elmwood Avenue, Box 665, Rochester, NY 14642,
USA (e-mail:
*University of Rochester School of Medicine and Dentistry, Rochester,
New York, USA.
Department of Biostatistics and Computational Biology, University of
Rochester Medical Center, Rochester, New York, USA.
Department of Orthopedics, University of Rochester Medical Center,
Rochester, New York, USA.
One or more of the authors has declared the following potential
conflict of interest or source of funding: Grant support from the Clinical
and Translational Science Institute (Grant No. UL1 RR024160 from the
National Institutes of Health) allowed access to REDCap via the University
of Rochester School of Medicine and Dentistry.
The Orthopaedic Journal of Sports Medicine, 2(4), 2325967114531177
DOI: 10.1177/2325967114531177
ª The Author(s) 2014
This open-access article is published and distributed under the Creative Commons Attribution - NonCommercial - No Derivatives License (
licenses/by-nc-nd/3.0/), which permits the noncommercial use, distribution, and reproduction of the article in any medium, provided the original author and source are
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exercise is effective with relatively minimal time invest-
A recent study found that participation
in CrossFit improved metabolic capacity and resulted in
improvements in fitness based on maximal oxygen uptake
max) and body composition. These improvements
were noted among subjects of both sexes and across all lev-
els of fitness.
A study conducted by the US Army found
that implementation of CrossFit among soldiers led to sig-
nificant improvements in soldiers’ physical fitness.
A con-
sensus paper by the Consortium for Health and Military
Performance and the American College of Sports Medicine
acknowledged the beneficial effects of extreme conditioning
programs while addressing concerns over the possible
injury rate and rhabdomyolysis.
The primary purpose of this pilot study was to investi-
gate the injury rate among CrossFit participants. A second-
ary objective was to identify trends and associations
between injury rates and demographic categories, gym
characteristics, and athletic abilities among CrossFit parti-
cipants. We aimed to establish a baseline for further
research and investigation into CrossFit. With identifica-
tion of risk factors for injury, we can establish effective
means of preventing these injuries. Similar strategies have
been applied to handball and soccer to reduce injury
General Design
This study utilized a cross-sectional design. Study data
were collected from October 2012 to February 2013 via
an electronic survey (see the Appendix, available at Data were col-
lected and managed using REDCap electronic data cap-
ture tools hosted at the University of Rochester.
REDCap (Research Electronic Data Capture) is a secure,
web-based application designed to supp ort data capture
for research studies, providing (1) an intuitive interface
for validated data entry, (2) audit trails for tracking data
manipulation and export procedures, (3) automated
export proced ures for seamless data downloads to com-
mon statistical packages, and (4) p rocedures for import-
ing data from external sources. To normalize data, we
chose to only use responses from CrossFit participants
who train at a CrossFit gym in the United States.
Responses from CrossFit athletes from outside the
United States or those who trained on their own were
excluded. The Institution al Review Board at th e Univer-
sity of Rochester approved this study.
Survey Development
The survey was developed from May 2012 to July 2012 via a
series of semistructured interviews with physicians and
CrossFit gym owners, coaches, and participants. It was
based on a survey developed to assess injury in track and
field participants.
Over the course of the interviews, the
survey was modified to reflect specific factors that should
be measured in CrossFit participants. The survey was then
piloted with multiple groups of CrossFit athletes (5 groups
of 3) and was adjusted according to feedback. From this we
established a 3-fold injury criterion that encompassed a
wide variety of injuries that can occur with CrossFit work-
outs. ‘‘Injury’’ encompassed any new musculoskeletal pain,
feeling, or injury that results from a CrossFit workout and
leads to 1 or more of the following options:
1. Total removal from CrossFit training and other out-
side routine physical activities for >1 week
2. Modification of normal training activities in dura-
tion, intensity, or mode for >2 weeks
3. Any physical complaint severe enough to warrant a
visit to a health professional
The argument for this definition and time requirement
is 3-fold. First, because of the constantly varied program-
ming of CrossFit workouts, athletes are often sore and
because of a particularly difficult workout may be unable
to exercise for several days. This soreness can often be con-
fused with injury. One week was the most commonly
reported time loss period among CrossFit athletes and
sports medicine physicians as to when suspected muscle
soreness was in reality a pathologic issue. Second, practice
in CrossFit consists of many different components, ranging
from gymnastics to power lifting. Therefore, when athletes
are unable to follow the original schedule, they can modify
it around their current injuries. This is defined as partial
time loss and enables them to continue training. Most ath-
letes reported that if they had to modify workouts for more
than 2 weeks they found that the injury was not going to
heal without medical attention. Last, any injury that
appeared to the athlete to require immediate medical atten-
tion from a health care professional should be reported.
This captures both acute injuries and transient injuries
that require the athlete to seek help from a medical profes-
sional but do not affect their training schedule.
We decided to use athlete-level data collection. While
CrossFit athletes regularly perform their workouts in gyms
under the supervision of coaches, often they do not consis-
tently train with the same coach, nor is the level of super-
vision similar to sports teams. CrossFit participants visit
a variety of health care professionals in the area, making
it impossible to use their care providers to gather this infor-
mation. Therefore, contacting the athletes directly is the
only means of assessing injury rate. To minimize recall bias
but maximize injury capture, we choose to survey the ath-
letes over a 6-month time period and created very specific
and concrete criteria for what constituted an injury.
Data Collection
A survey was electronically distributed to CrossFit gym
owners, coaches, and participants primarily in Rochester,
New York; New York City, New York; and Philadelphia,
Pennsylvania. Recipients of this survey were encouraged
to share the survey with members of their gym. Coaches,
owners, and participants were further encouraged to send
the survey to members of other gyms. In addition, the
2 Weisenthal et al The Orthopaedic Journal of Sports Medicine
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survey was made available to CrossFit participants via a
posting on the main CrossFit website. As a result, there
were a wide variety of responses from many distinct geogra-
phical locations, including athletes from outside the United
States. Additionally, many athletes responded who did not
train at CrossFit gyms but preferred to train on their own.
Exclusion criteria included training at a gym outside the
United States, training independently outside of a CrossFit
gym, and being younger than 18 years. Inclusion criteria
included being older than 18 years and training at a Cross-
Fit gym in the United States. This was in an effort to focus
our efforts primarily on CrossFit gyms and to limit geogra-
phical training bias. This was a single survey that recorded
demographic and participant characteristics (ie, sex, age,
experience, maximum lifts, and times) and the incidence
and characteristics of injuries incurred over the 6 months
prior to completing the survey. We specifically looked to
determine if there was any association between body part
injured and movement type and between injury rate and
age, sex, time of participation, training period for begin-
ners, trainer involvement, training time, rest days per
week, and length of time involved in CrossFit using chi-
square or Fisher exact tests. In addition, we investigated
the differences in rates of injury based on prior discomfort
in the injured area, prior injury to the injured area, and
final diagnosis of injury using the chi-square test for equal
proportions. All information, including diagnoses, obtained
for the study was from self-reports and was not indepen-
dently verified by a physician.
Data Analysis
Data analyses were performed using SAS software, version
9.3 (SAS Institute, Cary, North Carolina, USA). The use of
chi-square or Fisher exact tests and the chi-square test for
equal proportions were outlined in the previous paragraph.
All statistical tests were 2-sided, and a P value less than .05
was considered to be statistically significant.
Demographics/Gym Characteristics
There were a total of 468 responses, of which 386 met the
inclusion criteria of training at a CrossFit gym in the
United States (Figure 1). We focused our demographic data
collection on age, sex, and length of participation (Table 1).
The majority had been involved with CrossFit for 0 to
6 months (n ¼ 136; 35.2% ), trained for 30 to 60 minutes
at a time (n ¼ 319; 83.1%), took 2 to 3 rest days per
week (n ¼ 279; 72.8%), and exercised 4 to 5 days per week
Total responses
N = 468
Complete responses
n = 460
Incomplete responses
n = 8
Responses from US
n = 436
Responses from outside US
n = 24
Train at CrossFit gym in US
n = 386
Train outside CrossFit gym
n = 50
California - 29
Illinois - 32
Massachusetts - 18
New York - 215
Pennsylvania - 16
Other - 76
Figure 1. Study flowchart showing the methodology for inclusion criteria, the number of participants included, and where they
were from.
The Orthopaedic Journal of Sports Medicine Injury Rate Among CrossFit Athletes 3
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(n ¼ 279; 72.8%). Many gyms have a required training
period for beginners (n ¼ 325; 84.9%) and have trainers who
are present and actively correcting form during workouts
(n ¼ 219; 57.0%).
Injury Rate by Demographics/Gym Characteristics
Overall, we found that 75 participants (19.4%) had experi-
enced at least 1 injury resulting from a CrossFit workout in
the 6 months prior to filling out the survey that met the
defined injury criteria. Of this population, 63 participants
experienced 1 injury (84%), 10 experienced 2 injuries
(13.3%), and 2 experienced 3 injuries (2.7%).
We found no significant difference in injury rate across
age (n ¼ 381; P ¼ .56). We separated participants by the
amount of time they had been training in CrossFit. We
found no significant difference in injury rate based on
length of participation in CrossFit (n ¼ 386; P ¼ .099), but
athletes who had been participating in CrossFit for longer
periods of time tended to have longer training sessions
(n ¼ 384; P < .001) but not an increased number of sessions
per week (n ¼ 381; P ¼ .67). There was no significant differ-
ence in injury rate based on length of training session (n ¼
384; P ¼ .17). Days spent training per week did not show
any trends based on injury rate (n ¼ 383; P ¼ .16). Partici-
pants who attended a gym that required a training period
for beginners reported a lower injury rate (18.5%) than
training facilities that did not require a training period
(25.9%); however, this did not reach significance (n ¼ 383;
P ¼ .2). Injury rate was separated based on the maximum
weight participants could lift in various strength exercises
(deadlift, squat, press, clean and jerk), and there was no
significant difference between different groups. Five parti-
cipants failed to report their sex, so there were 381 partici-
pants included in the analysis of injury rate based on sex.
Males were significantly more likely to injure themselves
than females (n ¼ 381; P ¼ .03). A significant correlation
was noted between injury rate and level of coach supervi-
sion when men and women were considered together (Table
2). Females, however, were significantly more prone to seek
coach supervision as opposed to males (n ¼ 380; P ¼ .015).
When men and women were considered separately with
regard to injury rate and trainer involvement, the effect
of involvement of trainers had a decreasing effect on injury
rate for each sex, but neither subgroup reached significance
due to a reduced sample size. In subsequent analyses, the
effect of the involvement of trainers on injury rate was
found to be not significantly different for men versus
women, which justified analyzing the 2 groups
Injury Characteristics
CrossFit workouts often include a wide variety of exercises.
Across all exercises, the injury rates were significantly dif-
ferent across body parts (P < .001). The most common
injured parts were the shoulder (21/84), low back (12/84),
and knee (11/84). For gymnastic movements, injury rates
were significantly different across body parts (P ¼ .04),
with shoulder injured most often (7/17). For power lifting
movements, injury rates were significantly different across
body parts (P < .001), with lower back injured most often (9/
19) (Table 3). The majority had neither experienced any dis-
comfort in the injured area prior to the injury (n ¼ 88; P <
.001) nor had an injury to that same body part in the past
year (n ¼ 89; P < .001). The self-reported final diagnoses
were most co mmonly general inflammation and pain (n
¼ 25; 30.8%; P < .001), other (n ¼ 22; 27.2%), sprain/strain
(n ¼ 14; 17.2%), w hile rupture (n ¼ 3; 3.7%)anddislocation
(n ¼ 2; 2.5%) were relatively infrequent.
CrossFit is a blend of multiple synchronistic exercises, such
as gymnastics, power lifting, Olympic lifting, and endur-
ance activities. These movements are often performed at
a high intensity with little recovery time between exercises.
As such, some reports have predicted a high injury rate
among CrossFit participants because of repetitive use of
technical exercises at a high intensity.
We hypothesized
that this would not be true due to the level of supervision
at CrossFit gyms and an emphasis on instruction before
exercises are performed in a workout. In our study, we
found the overall injury rate in CrossFit was approximately
20%. This injury rate was gathered only from athlete-level
collection, and we depended on their reporting based on our
injury criteria to establish this injury rate. Although the
mechanism of injury would not be the same between run-
ning and CrossFit, running would be a reasonable logical
alternative for exercise in the recreational athlete. As a ref-
erence, epidemiological studies on runners have reported
injury incidence rates ranging from 19.4% to 79.3%.
Injury Rate Versus Trainer Presence
No Injury, n
(Row %)
Injury, n
(Row %)
Total, n
(Column %)
Level of trainer involvement
All of the time 187 (85.4) 32 (14.6) 219 (57)
Most of the time 102 (75.6) 33 (24.4) 135 (35)
Some of the time 20 (69.0) 9 (31.0) 29 (8)
Never 1 (100) 0 (0) 1 (0.2)
Total no. of injuries 310 74 384
P ¼ .028 for injury rate versus trainer presence.
Two subjects did not report trainer presence data.
Demographic Data by Age and Sex
Age Group, y Males, n (%)(n¼ 231) Females, n (%)(n¼ 150)
18-29 98 (42) 64 (42)
30-39 84 (36) 49 (32)
40-49 34 (15) 28 (18)
50-59 10 (4) 7 (5)
60-69 5 (2) 2 (1)
4 Weisenthal et al The Orthopaedic Journal of Sports Medicine
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track and field athletes, while a very different population
but with similar high-intensity ballistic mechanisms,
demonstrated a 42.8% 1-year retrospective injury preva-
lence, with gradual onset inflammation and pain being the
most common type of injury.
Participants reported injuring their shoulders, knees, and
low back most frequently. These were incurred most often
during power lifting and gymnastic movements. The
shoulder and lower back represented the most frequently
injured body areas during these exercises, respectively. This
finding is consistent with published injury rates among gym-
nasts, with athletes experiencing shoulder injuries most
Similar trends have been reported for Olympic
and power lifters.
Separate studies of elite weight and
power lifters have demonstrated a predominance of
shoulder, low back, and knee injuries, consistent with the
findings of this study, albeit in a different population.
Demographically, male athletes tended to injure them-
selves more frequently than female athletes. Interestingly,
females were more likely to seek help from a trainer, and
therefore, this may account for their decreased injury rate.
There was no significant difference in injury rate across
age, which persisted in female- and male-only samples.
This indicates that CrossFit is a workout program that can
function safely for athletes across all represented age
groups if performed in a safe environment.
Most reported injuries in CrossFit appear to be of an
acute n ature, as participants generally reported no prior
history of discomfort or injury to the body area they sub-
sequently injured. The majority of those injuries were
fairly mild, with particip ants reporting some general
inflammation/pain or sprain/strain as a result of these
injuries as opposed to more severe problems s uch as dis-
location or f racture. This sugg ests that the majority of
injuries in CrossFit are minor and return to participa-
tion is likely. However, potential re call b ias cannot be
excluded from those results, a s other studies have
demonstrated a 61% accuracy of self-reported diagnosis
in participants reporting over 12 months.
Injury prevention programs have become a common
adjunct to a variety of athletic activities.
To design an
injury prevention program, it is important to be aware of
injury rate and factors associated with injury in a
This is especially important considering the
business model of CrossFit. To a certain extent, CrossFit
represents a unified organization. However, unlike other
large fitness corporations, it does not directly supervise
gyms but instead gives them freedom to develop and grow
on their own. It does not require them to perform the pro-
gramming that is produced each day by CrossFit headquar-
ters in Washington, DC. Each gym owner is required to
have a CrossFit L1 certification, but aside from that, no
Injury Location Versus Movement Performed
Movement Type
Power Lifting
Olympic Lifting Gymnastics
Endurance Other Not Associated Total
Body part
Neck 0 2 0 0 0 0 2
Upper back 1 2 0 0 0 0 3
Middle back 0 0 0 0 1 0 1
Lower back 9 0 0 0 1 2 12
Shoulder 2 4 7 0 1 7 21
Upper arm 0 0 2 0 0 0 2
Elbow 0 2 1 0 0 1 4
Forearm 0 0 0 0 0 1 1
Wrist 1 2 0 0 1 0 4
Hand 0 0 1 0 0 0 1
Hip 1 1 1 1 2 0 6
Groin 0 0 1 0 1 1 3
Knee 4 1 2 2 1 1 11
Upper leg 1 0 0 0 1 1 3
Lower leg 0 0 0 2 1 0 3
Achilles/calf 0 1 1 0 3 0 4
Ankle 0 1 1 0 0 1 2
Foot/toe 0 0 0 0 0 1 1
19 14 17 5 13 16 84
Power lifting ¼ squat, deadlift, press/push press, bench press; Olympic lifting ¼ snatch, clean, jerk, clean and jerk; gymnastics ¼ pull-ups,
toes-to-bar, knees-to-elbows, lunges, muscle-ups, burpees, dips, gluteus-hamstring developer sit-ups, push-ups, rope climbs, handstand push-
ups, pistols; endurance ¼ rowing, running, sprints; Other ¼ kettlebell swings, thrusters, Turkish get-ups, box jumps, double unders.
P ¼ .004 for testing equal injury rates across body parts for power lifting.
P ¼ .04 for testing equal injury rates across body parts for gymnastics.
P < .001 for testing equal injury rates across body parts overall.
P < .001 for testing equal injury rates across movement type.
Five subjects did not report a specific movement.
The Orthopaedic Journal of Sports Medicine Injury Rate Among CrossFit Athletes 5
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further training is necessary. Therefore, it is possible to be
faced with a wide variation in quality between CrossFit
gyms based on the experience of the owner and coaches.
CrossFit maintains that the market will select out the gyms
with poor management and trainers and that the excep-
tional gyms will succeed.
Findings from this study may be used to guide physi-
cians, CrossFit owners, and coaches as they implement pre-
ventive strategies in their gyms and practices. This study
identified a specific area of focus that may be used to opti-
mize injury rate reduction strategies based on gym quality.
Increased supervision by CrossFit coaches was directly
related to injury rate. This could be because of several fac-
tors. Coaches guide CrossFit athletes through their work-
outs, help organize the class, and correct form. In
addition, they aid athletes in choosing the correct weight
for the workout. Often, workouts are posted with a pre-
scribed weight and repetition scheme, which can prove to
be excessive for even more experienced members. An expe-
rienced coach can help an athlete choose the right weight
and modify the repetition scheme to minimize injury based
on the athlete’s personal limitations. Our results indicate
that athlete experience level and overall involvement of the
coaches had the most pronounced effect on the health of the
athletes. As such, we recommend that potential partici-
pants evaluate the skill and attentiveness of the trainers,
as that is crucial to creating a safe environment.
As well, we feel that it is crucial for participants to be per-
sonally aware of these risks and strive to maintain form
throughout a workout, with specific focus on elements of
the movement related to the risk area. For example, when
an athlete is performing a power lifting movement, they
should be aware that the lower back is most commonly
injured in that type of movement and strive to maintain
an appropriate lumbar curve to avoid injury. A secondary
preventative strategy is to encourage patients with preex-
isting shoulder or low back pathology to avoid provocative
exercises or very gradually build up to performing those
exercises in a workout.
This study has limitations. We distributed our survey
electronically to current participants who then chose
whether to complete it. This introduces sampling bias
because participants who have had injuries may be more
likely to complete the survey. Alternatively, because we
only surveyed active CrossFit members, it is possible that
athletes who were injured and subsequently dropped out
may have been missed. We defined an acute injury as one
in which the athlete did not experience prior pain or dis-
comfort in the injured area. As this concentrates primarily
on the pain aspect of the injury, it does not take into account
that the mechanism of the injury could have started in a
prior workout without the appearance of pain. We had ath-
letes group their injury into general categories in place of
listing specific injuries, as there was no independent physi-
cian validation of the injury and our goal was to primarily
differentiate between mild and severe injuries. Further-
more, the retrospective nature of the study design intro-
duces the possibility of recall bias. A study examined
injury rates over a 12-month time period.
There was a per-
fect recall of whether an injury had been sustained during
that period, with a decreasing percentage of athletes recal-
ling the exact number of injuries, body region, or diagnosis.
Therefore, it stands to reason that the injury rate is accu-
rate, with some decreasing accuracy in the reported num-
ber of injuries, location of injury, and diagnosis, as all this
information was obtained from self-report. There was a
small amount of reported injuries, which limits the conclu-
sions on injury location and type. Despite these limitations,
this study also has several advantages. Our injury criteria
were concrete, encompassed the wide range of injuries that
are seen in CrossFit, and were assembled with input from a
number of different sources, including physicians, CrossFit
owners, and coaches. Although not validated, it also piloted
a means of electronic delivery to athletes, and this could
easily be replicated on a much larger scale to reach partici-
pants throughout the world. Finally, we sampled athletes
from a variety of different gyms throughout the country.
We have determined that injury rate differs based on trai-
ner involvement, and therefore it stands to reason that cer-
tain gyms with more effective or less effective trainers
could skew the injury rate in the study. However, because
of our wide distribution, we believe that this injury rate
comes closer to representing an average for CrossFit gyms
throughout the country as opposed to reporting the values
from a single gym.
This was structured as a pilot study, which could provide
areas of focus for further studies. A larger, prospective
study with a validated survey and examination of injury
rate with direct comparison with other recreational sports
would be the logical next step. The factors we have identi-
fied to be associated with injury patterns may then be
explored in more detail to help design effective preventative
strategies to reduce injury rates and aid CrossFit in grow-
ing as a safe and effective exercise program.
CrossFit is emerging as a popular form of competitive
exercise. As participation in CrossFit continues to expand,
injuries associated with involvement will likely grow com-
mensurately. Sports medicine physicians should have an
awareness of the elements of this form of exercise and be
prepared to treat the various patterns of injury incurred
by its athletes. Injury rates in CrossFit are comparable
with established injury rates for other recreational or com-
petitive athletes, with an injury profile resembling that of
gymnasts, Olympic weight lifters, and power lifters. The
increasing involvement of CrossFit trainers in coaching
participants corresponds to a decreasing injury rate. The
shoulder and lower back areas were the most commonly
injured body regions and most frequently were injured dur-
ing gymnastic and power lifting movements. Most injuries
in CrossFit are of an acute nature, without history of previ-
ous injury or symptoms in that same body area. In sum-
mary, we identified a preliminary injury rate in CrossFit,
characteristics of a gym that correlate with injury rates, the
most common location of injuries, and trends among Cross-
Fit participants that correlate with injury rates. This infor-
mation can be used by physicians treating patients who
6 Weisenthal et al The Orthopaedic Journal of Sports Medicine
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participate in CrossFit as well as owners and coaches who
work with athletes on a daily basis.
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The Orthopaedic Journal of Sports Medicine Injury Rate Among CrossFit Athletes 7
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... The aim of some studies was to assess the risk of injury among trainees, due to the high intensity of exercise and high levels of metabolic stress and fatigue, which directly translate into poor exercise technique [5][6][7]. The results of epidemiological studies on CrossFit ® training do not indicate direct causes of injuries [8,9]. Many authors agree that a large number of repetitions, combined with high loads and high intensity, is the factor responsible for injuries most often affecting the shoulder area and lumbar spine [10]. ...
... The above-mentioned shoulder joint and lumbar spine are most often injured during CrossFit ® weightlifting. Research confirms the highest level of trauma affecting those body parts in Olympic weightlifting, which are very often used in exercises performed in the same form during CrossFit ® training [8,28,29]. ...
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CrossFit® is a physical activity program and sport which is based on functional movements performed at high intensity and with high variability of exercises. It develops all motor skills. The study included 424 athletes (266 men and 158 women) from twelve centers in Poland, actively practicing CrossFit® between 18 and 60 years of age. A questionnaire consisting of 25 questions was used, which was divided into four subsections concerning the characteristics of the sample, training routine, injuries, and information about environment. In total, 48% of respondents participating in the study suffered at least one injury during their entire training history. The injuries suffered most often involved shoulder joint and lumbar spine. Men were found to face a higher risk of injury than women, at 32.78% vs. 15.33% (p = 0.027). The shorter the training period, the smaller the number of injuries observed among the trainees. It was also noted that the shorter the training period, the lower the number of injuries that occurred (p = 0.041). An increase in the number of training sessions per week did not increase the incidence of injuries (p > 0.05). Performing isometric exercises during warm-up reduced the likelihood of injury during CrossFit® training itself (p = 0.012). Training despite of concomitant acute pain had a significant adverse effect on the incidence of injuries (p = 0.002). The most common risk factors for injury in the CrossFit® training process include, in particular: gender, training experience, and length of training sessions. Proper warm-up including isometric exercises and training conducted without accompanying pain symptoms reduces the risk of injury.
... This indicates that a recovery program must be applied after functional training days. Also, Weisenthal et al. (2014) showed that male Crossfit athletes have a higher injury rate than females. This is thought to be because male athletes participating in the competitions are more than female athletes, and the competition is more in the male groups with more. ...
... Since the competition is high, the risk of hiding is also increasing. (Weisenthal et al., 2014). This situation requires male competitors to pay more attention to recovery times after Crossfit competitions. ...
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Purpose: The number of Crossfit competitions held is increasing day by day. The factors affecting the results in these competitions have become an important research topic. This study aimed to analyze whether the results of an international Crossfit competition held in Turkey differ according to the age, height, bodyweight, training time, number of daily steps, and athlete history parameters of the competitors. Method: The competition consisted of six stages and includes eight categories created according to the level of the athletes. For the study, a questionnaire containing this information was applied to the competitors (n = 184; 133 men, 51 women) and the data obtained were statistically compared with the scores at the end of the competition. Results: The findings of this study showed that age, height, body weight, exercise duration, and athlete history parameters affected the results of the functional training competition. In particular, it was observed that the height factor significantly affected the results of the competition, and the tall athletes scored better in most categories (p < 0.05). In addition, it was observed that age and body weight parameters created significant differences in some categories and some stages. It has been determined that the competitors with more than 10,000 daily steps were more unsuccessful in the total ranking. The daily exercise time of the athletes who were successful in the competition was 75-90 minutes. It has been noted that they did Crossfit training 5 days a week and that all finalist athletes were also interested in sports branches other than Crossfit. Conclusion: The findings of this research can provide enlightening information about the parameters that should be taken into account by the organizers of Crossfit competitions during the preparation phase of the competition content and the athletes during the preparation phase for these competitions
... Shoulder injuries are the result of the complexity and extreme demands of the WOD, which is often performed with high loads and improper technique [3,5,[7][8][9][10]. Shoulder injuries are also caused by the technical execution of exercises that require a high range of motion (ROM) and stability of the joint complex. ...
... If an athlete is tight in the wrists, elbows and shoulders, receiving the bar on the front shoulders and clavicles (catch phase of the clean movement) can cause two technical problems: the small and ring fingers pop off the bar, and the barbell lands on an anterior area of the deltoid muscle, possibly even on the sternum. Consequently, both technical errors lead to repetitive trauma/stress/overload to the joints and injury [8,[16][17][18][19]. ...
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Background: The aim of this study was to determine the optimal upper-limb range of motion (ROM) profile for the catch phase of the clean movement (CPCM) and to identify the key ROMs for performing the CPCM in CrossFit® athletes. Methods: A prospective cohort study of twenty CrossFit® athletes aged 20-36 years was conducted. Data were collected regarding age, anthropometrics, CrossFit® training experience and upper-limb ROM. The ROM was measured using the ROM-SPORT method. After 7 months, athletes performed a clean movement with a load of 80% one repetition maximum. A Bayesian Student's t-analysis, binary logistic regression analysis and Receiver Operating Characteristic analysis were performed. Results: The optimal upper-limb ROM profile that predicted correct CPCM performance was 78° in shoulder extension, 173° in shoulder flexion, 107° in shoulder external rotation, 89° in shoulder internal rotation, 153° in elbow flexion, 99° in elbow pronation and 92° in wrist extension (area under the curve ≥ 651; positive predictive value ≥ 80%). Shoulder external rotation, elbow pronation and wrist extension were found to be the most important ROMs for the efficient and safe performance of CPCM (area under the curve ≥ 854; positive predictive value ≥ 85.7%). Conclusion: The upper-limb ROM profile is associated with proper clean performance. Further studies are warranted to determine whether improving flexibility on upper-limb ROM may improve proper clean movement performance.
... Movements which all rely heavily on the main areas of injury. Weisenthal et al (2014) found that lower back injuries typically occur during powerlifting movements while gymnastic movements accounted for a relatively high rate of shoulder injuries. These results may be applicable to the training considerations of facilitators in the efforts to reduce injury rates in the future. ...
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This study aims to analyze the epidemiology of injury in CrossFit participants using a systematic review format. The inclusion and exclusion followed PICO recommendations. Reviewed items were selected using the PRISMA recommendations for systematic review. The Electronic Databases which were searched include; Google Scholar, Human Kinetics Journal, NCBI Journal of Sport Science, PUBMed and the SAGE Journals. Data was also collected by searching the NSCA Journal of Strength and Sport Conditioning Research databases. The methodological quality of each study was assessed using the STROBE Criteria recommendations. In total, 12 studies were selected for review.
... El cual tiene un sistema oficial de clasificación llamado "Open" donde los participantes demuestran sus aptitudes físicas para competir a nivel nacional e internacional (CrossFit, 2022). Una dinámica competitiva que surgió 12 años después de su génesis (Weisenthal et al., 2014). Por lo cual, cada año los practicantes de esta modalidad se preparan para competir en los Crossfit® Games (Cervantes et al., 2022). ...
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. El objetivo de este estudio fue determinar las diferencias de rendimiento en la fuerza máxima en sentadilla y banca plana, flexibilidad y composición corporal en los competidores de Crossfit® según su categoría. El diseño del estudio fue no experimental descriptivo de carácter transversal. Los participantes fueron 30 sujetos (edad 26.6 ± 5.2 años; masa 77 ± 9.4 kg; talla 172.8 ± 7 cm) practicantes de Crossfit® a nivel competitivo en las categorías intermedio, avanzado y elite. La fuerza máxima fue evaluada con la prueba de repetición máxima en sentadilla y banca plana; la flexibilidad se midió con el Flexitest y la composición corporal con bio-impedancia. Se encontraron diferencias estadísticamente significativas (p < .001) en la fuerza máxima al comparar las categorías competitivas. Estos valores de fuerza máxima aumentan a medida que avanza la categoría de competición. Sin embargo, no hubo diferencias en la flexibilidad, masa, porcentaje de grasa o porcentaje de masa muscular. Palabras clave: Rendimiento deportivo CrossFit®; entrenamiento funcional de alta intensidad; indicadores físicos; rendimiento de referencia; fuerza. Abstract. The purpose of this study was to determine performance differences in maximal squat and flat bench strength, flexibility, and body composition in CrossFit® competitors according to their category. The study design was non-experimental descriptive in a cross-sectional nature. The participants were 30 subjects (age 26.6 ± 5.2 years; mass 77 ± 9.4 kg; height 172.8 ± 7 cm) who practiced CrossFit® at a competitive level in the intermediate, advanced, and elite categories. Maximum strength was determined using the flat bench chest press and squat in the one repetition maximum test; flexibility was determined using the Flexitest; and body composition was determined using bio-impedance. When comparing the competitive categories, statistically significant differences (p < .001) in maximum strength were discovered. These values increase as the competition category progresses. However, there were no differences in flexibility, mass, percentage of fat, or percentage of muscle mass. Keywords: CrossFit® sport performance; high-intensity functional training; fitness indicators; physical indicators; benchmark performance; strength.
... The CF training is often characterized by the execution of exercises integrating large muscle groups (i.e., squat, push, press, etc.) or more specifically resistance training with free weights or body mass performed with high intensity with short rest intervals (Weston, Taylor, Batterham & Hopkins, 2014). Initially, this program was designed for people whose work required a certain level of physical form as well as muscle strength, like soldiers, policemen and firefighters (Weisenthal, Beck, Maloney, DeHaven, & Giordano, 2014). Because the CF training includes weightlifting (squats, deadlifting, power snatch, power clean) with a large number of repetitions during a short period, gymnastic movements (pull-ups, hand-walking, push-ups on the wall), and aerobic exercises (running, swimming, rowing) (Longe, 2012). ...
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CrossFit is recognized as one of the fastest-growing high-intensity functional training modes in the world. The study aimed to compare the effects of the CrossFit training program and traditional gym training on anthropometric measurements in healthy, active men. The study sample consisted of 50 participants who were divided into two groups, 22 participants who practiced the CrossFit training program (CFT group; 28.64±2.04 years; body height 181.74±6.96 cm; body mass: 72.75±5.53 kg), and 28 participants who applied traditional gym training (GT group; 26.89±2.99 years; body height: 184.52±7.80 cm; body mass: 74.86±8.48 kg). A total of ten anthropometric measurements (Body height, Body mass, BMI, Subscapular, Abdominal and Triceps skinfolds, Chest, Forearm, Upper arm, and Thigh circumferences) were monitored before and after twelve weeks. The Shapiro-Wilk test was used to test the normality of distribution. The multivariate analysis covariance (MANCOVA) and analysis of covariance (ANCOVA) were used to analyze the data. The results of this study indicated that there were statistically significant differences between groups in the Circumference of the upper arm (p=0.02), Thigh circumference (p=0.00), Chest circumference (p=0.03), and Subscapular skinfold (p=0.00). The findings of this study demonstrated that healthy, active males who participated in the 12-week CrossFit training program improved their anthropometric measurements more than those who trained in the traditional gym training.
... Its physical training program is characterized by high intensity stimulus with varied and multifunctional movements (Leitão et al., 2021;Sánchez-Silva et al., 2021) performed through exercises such as metabolic conditioning, gymnastic using body weight and Olympic lifting movements (Glassman et al., 2007;Tibana et al., 2015;Kramer et al., 2016;Montalvo et al., 2017). During their execution successive repetitions are requested and very restricted rest is used (Tibana et al., 2016;Weisenthal et al., 2014) or even without any recovery intervals (Butcher et al., 2015). ...
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CrossFit® is a training program characterized by high intensity stimulus with constantly varied and multifunctional movements that induces a significant range of physiological, hemodynamic and biochemical responses. Heart rate variability (HRV) can be used to measure how individuals react to physiological stress and fatigue. Thus, the aim of this study was to verify HRV and blood pressure acute responses during and after three sessions of Crossfit®. Nine subjects with more than one year of experience performed three different sessions of CrossFit® to verify the response of systolic blood pressure (SBP), diastolic blood pressure (DBP) and HRV. Significant reductions in HRV were observed through parasympathetic indexes (High Frequency(HF), p<0.001) and an increase in the activity of sympathetic indexes (Low Frequency (LF), p < 0.01; LF/HF, p<0.001) after all Crossfit® workouts. SBP decreased (p<0.05) and there were no significant differences between workouts of the day in both HRV and SBP. Different CrossFit® sessions induced similar activity of the autonomic nervous system with reduced HRV and post-exercise hypotension. Keywords. high intensity interval training; Fran; Megan; Diane; autonomic response; post-exercise hypotensive effect.
... 18 Also, males are more likely to sustain an injury than females. 19 The success experienced by this athlete with the provided protocol is important considering that the pectoralis major is essential to strenuous activities. 8 The results of this case report are similar to two previous case reports that described a post-op protocol for a pectoralis major rupture in a male snowboarding athlete and in a soldier of the US army. ...
Full-text available
The upper limbs are frequently injured during CrossFit® practice, and in some cases, surgical repair is recommended. The purpose of this case report was to describe the rehabilitation process performed after the surgical repair of a pectoralis major rupture in a CrossFit® practitioner. Design Case report. The subject was a 26-year-old man, with 1.75m and 69kg, who practiced CrossFit® for five years and sustained the injury during the execution of the ring dip. The rehabilitation protocol was of 16 weeks duration. Passive modalities and exercises focusing on range of motion, muscle strength, and CrossFit®-specific movements were performed. Shoulder range of motion was assessed through goniometry, and muscle strength was assessed through isometric dynamometry. Outcomes At week seven the subject had full range of motion, and at week fourteen achieved limb symmetry (Limb Symmetry Index-84.78-Abduction; 97.58-Adduction; 86.15-Internal Rotation; 85.06-External Rotation) in muscle strength. The subject returned to his previous level of athletic activities. Conclusions: A 16-week protocol performed with exercises focusing on range of motion, muscle strength, and CrossFit®-specific movements was abe to promote the return to sport at the pre-injury level in a CrossFit® practitioner.
This study quantified the effect of subthreshold loading histories that differed by joint posture (neutral, flexed), peak loading variation (10%, 20%, 40%), and loading duration (1000, 3000, 5000 cycles) on the post-loading Ultimate Compressive Tolerance (UCT), yield force, and regional Cartilaginous End Plate (CEP) indentation responses (loading stiffness and creep displacement). One hundred and fourteen porcine spinal units were included. Following conditioning and cyclic compression exposures, spinal units were transected and one endplate from each vertebra underwent subsequent UCT or microindentation testing. UCT testing was conducted by compressing a single vertebra at a rate of 3 kN/s using an indenter fabricated to a representative intervertebral disc size and shape. Force and actuator position were sampled at 100 Hz. Non-destructive uniaxial CEP indentation was performed at five surface locations (central, anterior, posterior, right, left) using a Motoman robot and aluminum indenter (3 mm hemisphere). Force and end-effector position were sampled at 10 Hz. A significant three-way interaction was observed for UCT (p = 0.038). Compared to neutral, the UCT was, on average, 1.9 kN less following each flexed loading duration. No effect of variation was observed in flexion; however, 40% variation caused the UCT to decrease by an average of 2.13 kN and 2.06 kN following 3000 and 5000 cycles, respectively. The indentation stiffness in the central CEP mimicked the UCT response. These results demonstrate a profound effect of posture on post-loading UCT and CEP behaviour. Control of peak compression exposures became particularly relevant only when a neutral posture was maintained and beyond the midpoint of the predicated lifespan.
Purpose of review: With the advent of social media combined with several large-scale promotions by nationwide gym chains, pediatric interest in strength training has reached new heights during the past few years. While this is a healthy way for young gym users to build strength and stay active, there are significant risks associated with improper utilization of exercise resources. Lack of adult supervision and guidance in the gym can lead to physical injury, inappropriate use of supplements, and body image issues. The purpose of this review is to provide pediatricians with up-to-date information about well tolerated exercise practices for pubertal and prepubertal youth. Recent findings: Current exercise trends may negatively impact both the physical and mental health of participants. Various physical injuries may occur when adolescents use gym equipment incorrectly under inadequate adult supervision. Use of unproven equipment such as waist trainers may cause bodily injury, and social media content on exercising and weight loss can negatively influence adolescent body image. Potential consequences include low self-esteem and uncommon body dysmorphic disorders, such as muscle dysmorphia. Further, the intense marketing of supplements can induce pediatric gym users to engage in inappropriate consumption behaviors. The increasing accessibility of commercial gyms to youth has increased the potential for children and adolescents to be exposed to such physical and mental health hazards. Summary: Greater knowledge regarding strength training techniques will help pediatricians guide their patients toward well tolerated and healthy gym habits. Caregivers and medical professionals should recognize the necessity of supervision, as well as the dangers of incorrect equipment use and unsafe trends to mitigate risks and maximize benefits of pediatric gym use.
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Background: The incidence of lower extremity injuries in female soccer players is high, but the risk factors for injuries are unknown. Purpose: To investigate risk factors for lower extremity injuries in elite female soccer players. Study design: Cohort study; Level of evidence, 3. Methods: Players in the Norwegian elite female soccer league (N = 12 teams) participated in baseline screening tests before the 2009 competitive soccer season. The screening included tests assessing maximal lower extremity strength, dynamic balance, knee valgus angles in a drop-jump landing, knee joint laxity, generalized joint laxity, and foot pronation. Also included was a questionnaire to collect information on demographic data, elite-level experience, and injury history. Time-loss injuries and exposure in training and matches were recorded prospectively in the subsequent soccer season using weekly text messaging. Players reporting an injury were contacted to collect data regarding injury circumstances. Univariate and multivariate regression analyses were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for ±1 standard deviation of change. Results: In total, 173 players underwent complete screening tests and registration of injuries and exposure throughout the season. A total of 171 injuries in 107 players (62%) were recorded; ligament and muscle injuries were the most frequent. Multivariate analyses showed that a greater body mass index (BMI) (OR, 1.51; 95% CI, 1.21-1.90; P = .001) was the only factor significantly associated with new lower extremity injuries. A greater BMI was associated with new thigh injuries (OR, 1.51; 95% CI, 1.08-2.11; P = .01), a lower knee valgus angle in a drop-jump landing was associated with new ankle injuries (OR, 0.64; 95% CI, 0.41-1.00; P = .04), and a previous knee injury was associated with new lower leg and foot injuries (OR, 3.57; 95% CI, 1.27-9.99; P = .02), whereas none of the factors investigated influenced the risk of new knee injuries. Conclusion: A greater BMI was associated with lower extremity injuries in elite female soccer players. Clinical relevance: Increased knowledge on risk factors for lower extremity injuries enables more targeted prevention strategies with the aim of reducing injury rates in female soccer players.
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To determine the effect of a 12-week high intensity intermittent exercise (HIIE) intervention on total body, abdominal, trunk, visceral fat mass, and fat free mass of young overweight males. Participants were randomly assigned to either exercise or control group. The intervention group received HIIE three times per week, 20 min per session, for 12 weeks. Aerobic power improved significantly (P < 0.001) by 15% for the exercising group. Exercisers compared to controls experienced significant weight loss of 1.5 kg (P < 0.005) and a significant reduction in total fat mass of 2 kg (P < 0.001). Abdominal and trunk adiposity was also significantly reduced in the exercising group by 0.1 kg (P < 0.05) and 1.5 kg (P < 0.001). Also the exercise group had a significant (P < 0.01) 17% reduction in visceral fat after 12 weeks of HIIE, whereas waist circumference was significantly decreased by week six (P < 0.001). Fat free mass was significantly increased (P < 0.05) in the exercising group by 0.4 kg for the leg and 0.7 kg for the trunk. No significant change (P > 0.05) occurred in levels of insulin, HOMA-IR, and blood lipids. Twelve weeks of HIIE resulted in significant reductions in total, abdominal, trunk, and visceral fat and significant increases in fat free mass and aerobic power.
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Little is known of injury patterns in track and field (athletics). Injury prevalence has been proposed as the most appropriate measure of the injury rate in sports where athletes are at risk for overuse problems. To ascertain 1-year retrospective and current prevalence of injury in elite track and field athletes to help plan injury prevention programs for this sport. Descriptive epidemiology study. Two hundred seventy-eight youth (16 years old) and adult athletes from an eligible study population of 321 athletes were included. The 1-year retrospective injury prevalence was 42.8% (95% confidence interval [CI], 36.9%-49.0%); the point prevalence was 35.4% (95% CI, 29.7%-41.4%). The diagnosis group displaying the highest injury prevalence was inflammation and pain in the gradual onset category (1-year prevalence, 20.9%; 95% CI, 16.2%-26.2%; and point prevalence, 23.2%; 95% CI, 18.4%-28.7%). A strong tendency for higher 1-year prevalence of 16.5% (95% CI, 12.2%-21.4%) than point prevalence of 8.5% (95% CI, 5.5%-12.5%) was recorded for sudden onset injuries in the diagnosis group sprain, strain, and rupture. The body region showing the highest injury prevalence was the knee and lower leg with 15.0% (95% CI, 11.0%-19.8%) 1-year prevalence and 13.7% (95% CI, 9.8%-18.3%) point prevalence, followed by the Achilles tendon, ankle, and foot/toe with 11.7% (95% CI, 8.2%-16.1%) 1-year prevalence and 11.4% (95% CI, 7.9%-15.8%) point prevalence. The injury prevalence is high among Swedish elite track and field athletes. Most of the injuries affect the lower extremities and are associated with a gradual onset. Although it is associated with a potential recall bias, the 1-year retrospective prevalence measure captured more sudden onset injuries than the point prevalence measure. Future prospective studies in track and field are needed to identify groups of athletes at increased risk.
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Low-volume high-intensity interval training (HIT) is emerging as a time-efficient exercise strategy for improving health and fitness. This form of exercise has not been tested in type 2 diabetes and thus we examined the effects of low-volume HIT on glucose regulation and skeletal muscle metabolic capacity in patients with type 2 diabetes. Eight patients with type 2 diabetes (63 ± 8 yr, body mass index 32 ± 6 kg/m(2), Hb(A1C) 6.9 ± 0.7%) volunteered to participate in this study. Participants performed six sessions of HIT (10 × 60-s cycling bouts eliciting ∼90% maximal heart rate, interspersed with 60 s rest) over 2 wk. Before training and from ∼48 to 72 h after the last training bout, glucose regulation was assessed using 24-h continuous glucose monitoring under standardized dietary conditions. Markers of skeletal muscle metabolic capacity were measured in biopsy samples (vastus lateralis) before and after (72 h) training. Average 24-h blood glucose concentration was reduced after training (7.6 ± 1.0 vs. 6.6 ± 0.7 mmol/l) as was the sum of the 3-h postprandial areas under the glucose curve for breakfast, lunch, and dinner (both P < 0.05). Training increased muscle mitochondrial capacity as evidenced by higher citrate synthase maximal activity (∼20%) and protein content of Complex II 70 kDa subunit (∼37%), Complex III Core 2 protein (∼51%), and Complex IV subunit IV (∼68%, all P < 0.05). Mitofusin 2 (∼71%) and GLUT4 (∼369%) protein content were also higher after training (both P < 0.05). Our findings indicate that low-volume HIT can rapidly improve glucose control and induce adaptations in skeletal muscle that are linked to improved metabolic health in patients with type 2 diabetes.
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The effect of regular aerobic exercise on body fat is negligible; however, other forms of exercise may have a greater impact on body composition. For example, emerging research examining high-intensity intermittent exercise (HIIE) indicates that it may be more effective at reducing subcutaneous and abdominal body fat than other types of exercise. The mechanisms underlying the fat reduction induced by HIIE, however, are undetermined. Regular HIIE has been shown to significantly increase both aerobic and anaerobic fitness. HIIE also significantly lowers insulin resistance and results in a number of skeletal muscle adaptations that result in enhanced skeletal muscle fat oxidation and improved glucose tolerance. This review summarizes the results of HIIE studies on fat loss, fitness, insulin resistance, and skeletal muscle. Possible mechanisms underlying HIIE-induced fat loss and implications for the use of HIIE in the treatment and prevention of obesity are also discussed.
The objective of this study was to describe shoulder injuries in a nationally representative sample of high school athletes playing 9 sports. A national estimate of shoulder injuries among high school athletes was subsequently calculated. Injury data were collected in 9 sports (boys' football, soccer, basketball, wrestling, and baseball; girls' soccer, volleyball, basketball, and softball) during the 2005-2006 through 2011-2012 academic years from a nationally representative sample of high schools via High School Reporting Information Online. During the 2005-2006 through 2011-2012 academic years, high school athletes in this study sustained 2798 shoulder injuries during 13 002 321 athlete exposures, for an injury rate of 2.15 per 10 000 athlete exposures. This corresponds to a nationally estimated 820 691 injuries during this time period. Rates of injury were higher in competition as compared with practice (rate ratio = 3.17 [95% confidence interval: 2.94-3.41]). The highest rate of injury was in football (4.86) and the lowest in girls' soccer (0.42). The most common types of injury were strain/sprain (37.9%) and dislocation/separation (29.2%). Boys were more likely than girls to sustain their injuries after contact with another person or with the playing surface. Surgical repair was required for 7.9% of the injuries. Time loss from athletic participation varied among sports, with 40.7% of athletes returning within 1 week, whereas 8.2% were medically disqualified for their season/career. High school shoulder injury rates and patterns varied by sport and gender. Prospective epidemiologic surveillance is warranted to discern trends and patterns to develop evidence-based interventions to prevent shoulder injuries.
The purpose of this study was to examine the effects of a crossfit-based high intensity power training (HIPT) program on aerobic fitness and body composition. Healthy subjects of both genders (23 males, 20 females) spanning all levels of aerobic fitness and body composition completed 10 weeks of HIPT consisting of lifts such as the squat, deadlift, clean, snatch, and overhead press performed as quickly as possible. Additionally, this crossfit-based HIPT program included skill work for the improvement of traditional Olympic lifts and selected gymnastic exercises. Body fat percentage was estimated using whole body plethysmography and maximal aerobic capacity (VO2max) was measured by analyzing expired gasses during a Bruce protocol maximal graded treadmill test. These variables were measured again following 10 weeks of training and compared for significant changes using a paired t-test. Results showed significant (P<0.05) improvements of VO2max in males (43.10±1.40 to 48.96±1.42 ml/kg/min) and females (35.98±1.60 to 40.22±1.62 ml/kg/min) as well as decreased body fat percentage in males (22.2±1.3 to 18.0±1.3) and females (26.6±2.0 to 23.2±2.0). These improvements were significant across all levels of initial fitness. Significant correlations between absolute oxygen consumption and oxygen consumption relative to body weight was found in both men (r=0.83, P<0.001) and women (r=0.94, P<0.001), indicating HIPT improved VO2max scaled to body weight independent of changes to body composition. Our data shows that HIPT significantly improves VO2max and body composition in subjects of both genders across all levels of fitness.
The aim of this study was to study the impact of a combined long-term lifestyle and high-intensity interval training intervention on body composition, cardiometabolic risk, and exercise tolerance in overweight and obese subjects. Sixty-two overweight and obese subjects (53.3 ± 9.7 yrs; mean body mass index, 35.8 ± 5 kg/m) were retrospectively identified at their entry into a 9-mo program consisting of individualized nutritional counselling, optimized high-intensity interval exercise, and resistance training two to three times a week. Anthropometric measurements, cardiometabolic risk factors, and exercise tolerance were measured at baseline and program completion. Adherence rate was 97%, and no adverse events occurred with high-intensity interval exercise training. Exercise training was associated with a weekly energy expenditure of 1582 ± 284 kcal. Clinically and statistically significant improvements were observed for body mass (-5.3 ± 5.2 kg), body mass index (-1.9 ± 1.9 kg/m), waist circumference (-5.8 ± 5.4 cm), and maximal exercise capacity (+1.26 ± 0.84 metabolic equivalents) (P < 0.0001 for all parameters). Total fat mass and trunk fat mass, lipid profile, and triglyceride/high-density lipoprotein ratio were also significantly improved (P < 0.0001). At program completion, the prevalence of metabolic syndrome was reduced by 32.5% (P < 0.05). Independent predictors of being a responder to body mass and waist circumference loss were baseline body mass index and resting metabolic rate; those for body mass index decrease were baseline waist circumference and triglyceride/high-density lipoprotein cholesterol ratio. A long-term lifestyle intervention with optimized high-intensity interval exercise improves body composition, cardiometabolic risk, and exercise tolerance in obese subjects. This intervention seems safe, efficient, and well tolerated and could improve adherence to exercise training in this population.
A potential emerging problem associated with increasingly popularized extreme conditioning programs (ECPs) has been identified by the military and civilian communities. That is, there is an apparent disproportionate musculoskeletal injury risk from these demanding programs, particularly for novice participants, resulting in lost duty time, medical treatment, and extensive rehabilitation. This is a significant and costly concern for the military with regard to effectively maintaining operational readiness of the Force. While there are certain recognized positive aspects of ECPs that address a perceived and/or actual unfulfilled conditioning need for many individuals and military units, these programs have limitations and should be considered carefully. Moreover, certain distinctive characteristics of ECPs appear to violate recognized accepted standards for safely and appropriately developing muscular fitness and are not uniformly aligned with established and accepted training doctrine. Accordingly, practical solutions to improve ECP prescription and implementation and reduce injury risk are of paramount importance.