Perfil de lesões em praticantes de CrossFit: revisão sistemática

Functional capacity and risk of injury in CrossFit practitioners measured through smartphone apps

BACKGROUND

CrossFit is a high intensity functional training that tends to challenge physical limits. The objectives of this study were to assess functional capacity, prevalence and risk of injury in CrossFit practitioners.

METHODS

This cross-sectional, observational and prospective study evaluate the rate of injuries that occurred in CrossFit practitioners in the last 12 months and their functional capacities. The sample was given for convenience, with a total of 22 participants. Functional capacities and risk of injury were measured by functional tests using PHAST and Clinometer applications. The prevalence of injuries was cataloged using the Nordic Musculoskeletal Questionnaire.

RESULTS

5% of the injuries occurred in the neck; 9% in shoulder, hip, thighs, ankles and feet; 14% in the lumbar spine and knees. The worst functional results were for the shoulder medial rotation ROM test, where 86-95% of the athletes were classified as "Bad"; the dorsiflexion ROM test also performed poorly in 68% of athletes.

CONCLUSION

This study shows that the CrossFit practice suggests that the injury prevalence is relatively low, affecting mainly knees, lumbar spine, wrists and hands. However, the risk of injuries shown by the functional musculoskeletal assessment is higher, especially in the shoulder and ankle, and it is important for the practitioner to realize a specific functional assessment before starting training.

Musculoskeletal Injury Prevalence, Pain Perception, and Physical Activity Level Among Brazilian Strength and Cross-Training Practitioners

In this study, we sought to determine the prevalence of musculoskeletal injuries, perceived pain, and physical activity level among Brazilian practitioners of strength training (ST) and functional fitness (FF). Participants were 311 men and women who trained in 10 FF training centers and seven ST gyms. Each participant completed surveys of the prevalence of musculoskeletal injuries, their pain perception, and their physical activity level. A chi square test was used to analyze associations between groups and distributions of injuries. When any significant difference was observed, the difference score was analyzed through the adjusted residual values. Fisher's exact test was used to determined the associations between musculoskeletal injury prevalence and training modality (FF and ST) and between musculoskeletal injury prevalence and practice frequency (times/wk). To measure the magnitude of association between variables, the Phi coefficient was calculated for 2x2 associations and Cramer's V was used whenever the distributions were outside this standard. When the dependent variable presented a dichotomous characteristic, an Odds Ratio (OR) was calculated with a confidence interval of 95%. We found a higher musculoskeletal injury prevalence in the axial skeleton (n = 52; 83.88%) in FF practitioners and in the lower limbs of ST practitioners (n = 9; 52.96%). When the physical activity level cutoff point was set at 300 minutes per week, there was a significant relationship between physical activity and training modality (p = 0.005). There was also a significant association between pain perception and musculoskeletal injury (p < 0.001). Clinical follow-up was a protective factor to being injured (OR = 0.18; CI = 0.06-0.49), and, even after multivariate analysis this significant association was maintained (OR = 0.03; CI = 0.01 - 0.08). Thus, FF practitioners reported more musculoskeletal injuries than STs, and follow-up medical or physical therapy was a protective factor to these injuries. FF practitioners also had a higher level of weekly physical activity weekly than ST practitioners. Functional fitness practitioners may be at a higher risk of injuries than those who participate in traditional strength training.

Effects of High-Intensity Functional Training (HIFT) on the Functional Capacity, Frailty, and Physical Condition of Older Adults with Mild Cognitive Impairment: A Blind Randomized Controlled Clinical Trial

Physical exercise has been established as an intervention in the integral approach for the physical, functional, and social health of older adults. The objective of this study was to determine the effects of a high-intensity functional training (HIFT) program on the physical condition and functional capacity of an elderly Colombian population with mild cognitive impairment. This research corresponds to a blind randomized controlled clinical trial. A total of 169 men and women aged over 65 years were evaluated and distributed in two groups: the experimental group that received a 12-week HIFT intervention (n = 82) and the control group (n = 87) that received general recommendations on the benefits of physical exercise. The outcome variables included physical condition, assessed using the Senior Fitness battery (SNB); Fried's frailty phenotype was applied, and gait and balance were assessed using the Tinetti scale. For the functional variables, activities of daily living, instrumental activities of daily living, and advanced activities of daily living were evaluated. All variables were measured pre- and post-intervention. Statistically significant improvements were observed in the IG for gait stability and balance (p < 0.001), as well as for independence in activities of daily living (p = 0.003), and instrumental and advanced activities (p < 0.001). Likewise, greater functionality was found when assessed with the SNB (p < 0.001), except for upper limb strength. The frailty classification did not show changes post-intervention (p = 0.170) nor in the group x time interaction. MANCOVA analysis showed that regardless of gender, health level, age, BMI, cognition, and health level, the HIFT intervention produced better results in functional capacity, balance, and gait (F = 0.173, p < 0.001, Wilks' λ = 88.231).

Which resistance training is safest to practice? A systematic review

BACKGROUND

The combination of resistance training (RT) and aerobic training is believed to achieve the best effects. Several different aerobic training methods have emerged in combination with or as a substitute for traditional RT. This study wished to verify which RT is safest in terms of injury prevalence and incidence. Also, it ascertained the characteristics of the injured subjects, the level of severity of the injuries and what definitions of injuries the available studies use.

METHODS

This systematic review followed the PRISMA recommendations and was registered in PROSPERO with the number CRD42021257010. The searches were performed in the PubMed, Cochrane and Web of Science, electronic databases using the Medical Subject Headings terms "Resistance training" or "Strength training" or "Crossfit" or "Weightlifting" or "Powerlifting" combined (AND) with "Injury" or "Injuries" or "Sprain" AND "Incidence" or "Prevalence" AND "Epidemiology" or "Epidemiological" in the title or abstract. The last search was performed on March 2023. To be included in the review, the studies had to be available as full text, be clinical trials focusing on epidemiological injuries of resistance training. There was no time limit for the selection of articles. To assess the quality of the studies, the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) was used.

RESULTS

The initial literature search resulted in 4982 studies. After reading the titles, abstracts and full text, 28 articles were selected for data extraction. Seventeen investigated the injuries in HIFT/CrossFit, three in powerlifting, three in strength training, three in weightlifting and one in strongman. In addition, one study examined the HIFT/CrossFit and weightlifting. The incidence of injuries presented in the studies ranged from 0.21/1000 h to 18.9/1000 h and the prevalence of injuries was 10% to 82%. In the quality assessment for STROBE, five studies were classified at level A, 21 at level B and two at level C.

CONCLUSION

This systematic review showed that traditional strength training is the safest RT method, and strongman is the least safe regarding injuries. Few studies have been rated highly according to STROBE. Furthermore, few studies have been published on some RT methods. These two factors make it difficult to generalize the results.

PREVALENCE AND LOCATION OF PAIN IN CROSSFITTERS IN A CITY IN THE SOUTH OF MINAS GERAIS

ABSTRACT Introduction: CrossFit was created to develop the physical and motor skills of athletes in all categories, aiming for the physical limit of everyone who practices it, in accordance with their toning capacity. Objectives: Considering that the quest for these limits has resulted in an increasing number of CrossFitter injuries, the objective of this study was to define the levels of pain and the anatomical regions affected among CrossFitters in the city of Alfenas. Methods: The Corlett diagram was used in association with the Visual Analog Scale, which ranges from 1 to 10. Three CrossFit gyms in the city of Alfenas were visited and their CrossFitters were invited to participate in this research. Those who agreed to participate (109) signed the informed consent form. Results: Of the total number of participants interviewed, 86.63% reported having some type of pain in their daily CrossFit routine. Of the total number of respondents who experienced pain, 56.68% were women and 43.32% were men. The three areas that stand out with the highest prevalence of pain were shoulders at 51.37%, the lower back at 44.03%, and the knees at 40.36%. The One-way ANOVA test was applied with p≤ 0.05 and there was no statistical difference between the pain groups (trunk pain, right limb pain, and left limb pain). Conclusion: When we applied the Corlett diagram to verify the degree and anatomical regions of pain in CrossFitters in the city of Alfenas, it was evident that CrossFit is a sport that, by demanding a lot from those who practice it, ends up causing moderate to severe pain, especially in the shoulder, lumbar, and knee regions. Level of evidence II; Retrospective study.

PREVALÊNCIA E LOCAL DE DOR EM PRATICANTES DE CROSSFIT EM UMA CIDADE DO SUL DE MINAS GERAIS

RESUMO Introdução: O CrossFit foi criado para desenvolver as habilidades físicas e motoras de atletas de todas as categorias, visando o limite físico de cada praticante, de acordo com sua capacidade tônica. Objetivos: Considerando que a busca desses limites tem acarretado cada vez mais lesões nos praticantes, este estudo visou estabelecer o grau de dor e a região anatômica afetada decorrentes do CrossFit na cidade de Alfenas. Métodos: Para tal, foi usado o diagrama de Corlett associado à Escala Visual Analógica, que varia de 0 a 10. Três academias de CrossFit da cidade de Alfenas foram visitadas e os frequentadores foram convidados a participar desta pesquisa e todos que concordaram em participar (109) assinaram o termo de consentimento livre esclarecido. Resultados: Do total de entrevistados, 86,63% relataram ter algum tipo de dor na prática diária de CrossFit. Do total de entrevistados que apresentaram dor, 56,68% eram mulheres e 43,32% homens. Entre os três locais de maior prevalência de dor destacaram-se ombros, 51,37%; parte inferior das costas/do dorso, 44,03%; joelho, 40,36%. Foi aplicado o teste ANOVA One Way com p ≤ 0,05 e não houve diferença estatística entre os grupos de dor (dor no tronco, dor no membro direito e dor no membro esquerdo). Conclusão: Ao aplicar o diagrama de Corlett para verificar o grau de dor e a região anatômica nos praticantes de CrossFit da cidade de Alfenas, evidenciou-se que o CrossFit é um esporte que, por exigir muito dos praticantes, acaba acarretando dores de moderada a grave, principalmente nas regiões do ombro, lombar e do joelho. Nível de evidência II; Estudo retrospectivo.

Risk Factors for Musculoskeletal Injury in CrossFit: A Systematic Review

The objective of this systematic review was to identify potential risk factors for injury in CrossFit participants. Embase, Medline, Web of Science, Cochrane, CINAHL, Google Scholar, and SportDiscuss databases were all searched up to June 2021. Cohort studies that investigated risk factors for CrossFit injuries requiring medical attention or leading to time loss in sports were included. A best-evidence synthesis was performed combining all the outcomes from prospective cohort studies. From 9,452 publications identified, we included three prospective cohort studies from which two had a low risk of bias and one a high risk of bias. The studies examined 691 participants of whom 172 sustained an injury. There was limited evidence that switching between prescribed and scaled loads during training is associated with increased injury risk and that increased duration of participation is a protective factor for injury. This could mean that novice CrossFit athletes and those increasing their training load should have closer supervision by CrossFit coaches. These risk factors should be considered when developing preventive interventions.

Epidemiology of High Intensity Functional Training (HIFT) injuries in Brazil

BACKGROUND

High intensity functional training (HIFT), usually called CrossFit, is a physical training that has gained much popularity in the past few years. The risk of acute and overuse injuries in HIFT is unclear. This study evaluated the incidence of injuries in HIFT, characterizing severity, location, and associated risk factors.

METHODS

This cross-sectional study was conducted between January and May 2021. HIFT practitioners were recruited through social media and answered an online questionnaire on training characteristics and injury history.

RESULTS

A total of 606 subjects (264 male and 342 female) were included. The average age of the participants was 29.78 ± 7.14 years. The mean height was 169.60 ± 8.96 cm, and the mean body mass was 73.69 ± 13.11 kg. Overall, participants were involved in HIFT for an average of 25.36 ± 20.29 months. A total of 58.6% of participants took part in 5 to 6 training sessions per week, 31.7% practiced 5 to 6 h per week. 62.7% of the responders performed other physical activities in parallel, 98.2% performed warm-up before the training, and a formal cooldown was accomplished by 29.4% of participants. 6.8% of athletes followed individual worksheets. 45.9% of participants participated in competition.

CONCLUSIONS

The overall rate of injuries was 3.51/1000 h. 59.2% of subjects experienced two or more injuries. The shoulder was involved in 21.3% of cases, lower back in 18.3%, and the knee in 13.4%. No difference was found in injury rate between males and females. Experienced athletes were more prone to injury compared to those who trained under 12 months. Approximately the half of injuries did not cause training interruption. No difference was found in injury rate between males and females. The purpose of the participant did not impact the injury rate, nor did the practice of warm-up and cooldown, the time of weekly training, the league and level of competition. Finally, the participation in other sports in parallel did not demonstrated association with the injury occurrence.

TRIAL REGISTRATION

The present study was approved by the Ethics and Research Committee by Plataforma Brazil and follows the Resolution 466/2012/CNS/MS/CONEP.

Quantifying CrossFit®: Potential solutions for monitoring multimodal workloads and identifying training targets

The design of high-intensity functional training (HIFT; e. g., CrossFit^®) workouts and targeted physiological trait(s) vary on any given training day, week, or cycle. Daily workouts are typically comprised of different modality and exercise combinations that are prescribed across a wide range of intensities and durations. The only consistent aspect appears to be the common instruction to maximize effort and workout density by either completing "as many repetitions as possible" within a time limit (e.g., AMRAP, Tabata) or a list of exercises as quickly as possible. However, because effort can vary within and across workouts, the impact on an athlete's physiology may also vary daily. Programming that fails to account for this variation or consider how targeted physiological systems interrelate may lead to overuse, maladaptation, or injury. Athletes may proactively monitor for negative training responses, but any observed response must be tied to a quantifiable workload before meaningful changes (to programming) are possible. Though traditional methods exist for quantifying the resistance training loads, gymnastic movements, and cardiorespiratory modalities (e.g., cycling running) that might appear in a typical HIFT workout, those methods are not uniform, and their meaning will vary based on a specific exercise's placement within a HIFT workout. To objectively quantify HIFT workloads, the calculation must overcome differences in measurement standards used for each modality, be able to account for a component's placement within the workout and be useful regardless of how a workout is commonly scored (e.g., repetitions completed vs. time-to-completion) so that comparisons between workouts are possible. This review paper discusses necessary considerations for quantifying various HIFT workout components and structures, and then details the advantages and shortcomings of different methods used in practice and the scientific literature. Methods typically used in practice range from being excessively tedious and not conducive for making comparisons within or across workouts, to being overly simplistic, based on faulty assumptions, and inaccurate. Meanwhile, only a few HIFT-related studies have attempted to report relevant workloads and have predominantly relied on converting component and workout performance into a rate (i.e., repetitions per minute or second). Repetition completion rate may be easily and accurately tracked and allows for intra- and inter-workout comparisons. Athletes, coaches, and sports scientists are encouraged to adopt this method and potentially pair it with technology (e.g., linear position transducers) to quantify HIFT workloads. Consistent adoption of such methods would enable more precise programming alterations, and it would allow fair comparisons to be made between existing and future research.

Predicting the Clean Movement Technique in Crossfit® Athletes Using an Optimal Upper-Limb Range of Motion: A Prospective Cohort Study

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.

Injury in CrossFit®: A Systematic Review of Epidemiology and Risk Factors

OBJECTIVE

To review the characteristics of the injuries among CrossFit® practitioners, including prevalence and incidence, nature, location, and risk factors.

METHODS

PubMed/MEDLINE, EMBASE, Web of Science, Scopus, and SPORTDiscus databases were searched from inception through August 2020, and English-language articles reporting on CrossFit®-related injuries were included. Data including sample (sex, age, and demographics) and injuries' characteristics (prevalence, incidence rate, nature, location, percentage of injuries requiring surgery and risk factors) were extracted.

RESULTS

Overall, twenty-five studies involving a total of 12,079 CrossFit® practitioners met the inclusion criteria. The mean prevalence of injuries among the included studies was 35.3%, with an incidence rate varying between 0.2 and 18.9 per 1000 hours of training. The most injured areas were shoulder (26%), spine (24%), and knee (18%). Among the studies that reported the injuries requiring surgery, the mean percentage was 8.7%. Regarding the risk factors associated with injuries, older age, male sex, a greater body mass index, the existence of previous injuries, the lack of coach supervision, the experience on CrossFit® and the participation in competitions were reported by the studies.

CONCLUSIONS

CrossFit® training has an injury incidence rate similar to weightlifting and powerlifting. Findings from the studies suggest that the most affected areas are shoulder, spine, and knee. The limited quality of the studies prevents us from drawing solid conclusions about injury risk factors.

Isokinetic force-power profile of the shoulder joint in males participating in CrossFit training and competing at different levels

Background

As participants who engage in CrossFit training and competition perform a large volume of high intensity overhead activities, injuries to the shoulder are one of the most common in this sport. Previous research in other sports has indicated that the isokinetic force power profile of the shoulder joint (IPSJ) rotator muscles may assist in the prediction of shoulder injury.

Aim

Therefore, the objective of this study was to determine the IPSJ in males engaged in CrossFit training at different competitive levels.

Methods

In a cross-sectional study design, participants (age, 24.1 ± 2.7 years) classified as ‘beginner’ (n = 6), ‘intermediate’ (n = 7) or ‘advanced’ (n = 9) provided informed consent to participate in this study. The IPSJ assessment involved rotational and diagonal movements, including internal and external shoulder rotator muscles, at both 180°.s⁻¹ and 300°.s⁻¹. The variables analysed were peak torque/body mass (%), mean power (W) and the external/internal peak torque/body mass ratio (%). A Kruskal–Wallis test was used to compare the IPSJ of the three groups, with Dunn’s test used for post-hoc analysis. The alpha level was set at p < 0.05.

Results

The IPSJ showed greater torque and power values in those who competed at the advanced level as compared to those at a lower competitive level (i.e. intermediate, beginner). This was observed mainly for the internal rotation and internal diagonal movements at both 180°.s⁻¹ and 300°.s⁻¹. However, such differences between competitive levels were, in general, absent for the external rotation and external diagonal movements. Moreover, the participants from the advanced competitive level exhibited an imbalance of peak torque between the muscles responsible for the external–internal rotational and external-internal diagonal movements of the shoulder (i.e. peak torque external/internal ratio <66%), particularly in the dominant shoulder.

Conclusion

These findings suggest greater development of the shoulder internal rotators and a higher probability of shoulder injury in CrossFit athletes at the advanced competitive level. Based on these results, participants engaged in CrossFit training and competition may wish to increase the volume of training for the shoulder external rotator muscles to complement the large increases in shoulder internal rotator strength that occur as a part of their regular training regimes.

Injuries in functional fitness: an updated systematic review

INTRODUCTION

This study aimed to analyze injuries of functional fitness participants through a systematic review.

EVIDENCE ACQUISITION

A systematic search of the literature was conducted in CINAHL, EMBASE, PEDro, PubMed, SCOPUS, SPORTDiscus, and Web of Science, supplemented by searching in the grey literature, from 2017 to November 2020. This systematic review followed the PRISMA guidelines and was documented in the PROSPERO registry (CRD42020201259). Two reviewers independently extracted data including methodological (age, sex, time of practice, location, period, time frame, and completion rate) and injury (definition, diagnosis, prevalence, incidence, severity, mechanism, type, location, risk factors, and treatment) variables, as well as assessing study quality and risk of bias.

EVIDENCE SYNTHESIS

Twenty-six studies were included (10967, range 6-3049, participants). Injury was defined fairly differently across studies. The majority of studies used a retrospective study design and the main variables reported were prevalence, body location, and associated factors of injuries. The mean prevalence of musculoskeletal injuries was 32.8%, ranging from 2.4 to 60.6%, and the injury incidence per 1000 hours ranged from 0.21 to 67 36. The most affected body location in the studies was the shoulder, followed by lumbar spine, and knee. Muscle, joint, and ligament/tendon injuries were the most frequently reported. The majority of studies were of moderate methodological quality. All studies were considered as high risk of bias.

CONCLUSIONS

This review broadened the scope of 75 previous reviews on injuries in functional fitness. There have been few investigations regarding severity, mechanism, and treatment of injuries, so further research is warranted.

Psychological variables of CrossFit participants: a systematic review

Objective

This study aimed to review the existing literature concerning the psychological variables of CrossFit participants.

Methodology

This review followed the PRISMA guidelines and was documented in the PROSPERO registry (CRD42018091177). Six electronic databases (SCOPUS, PubMed, SPORTDiscus, Web of Science, EMBASE, and Cochrane) were searched from their inception through July 2020. The methodological quality of the studies was assessed.

Results

Thirty-four studies met the inclusion criteria. We observed an increase in satisfaction, clinical addiction, and enjoyment among participants related to exercise, social improvement, and high intrinsic motivation to participate for the purpose of enjoyment, challenge, and affiliation. Perceptions of effort were high among CrossFit participants. Some studies found that the reaction time was impaired after the CrossFit session, whereas others found no changes in mental health, self-esteem, and well-being after training.

Conclusion

Adherence and maintenance of the practice of CrossFit are related to psychological variables such as motivation and satisfaction of basic psychological needs. CrossFit participants demonstrated high perception of effort, intrinsic motivation, and reasons for practice such as enjoyment, challenge, and affiliation. The quality assessment demonstrated the need for more detail in the methods section of future investigations. Additional high-quality studies are needed to investigate the effects of CrossFit training on the mental health of participants.

Electronic supplementary material

The online version of this article (10.1007/s11332-020-00685-9) contains supplementary material, which is available to authorized users.

Breaking the myths of competition: a cross-sectional analysis of injuries among CrossFit trained participants

Objectives

The purpose of this study was to examine the injury rates of individuals engaged in CrossFit training and examine the risk of injury associated with competition.

Study design

Cross-sectional analysis.

Methods

Descriptive statistics, including injury incidence and rates, were examined for individuals reporting participation in a CrossFit sanctioned competition between 2013 and 2017. To examine the odds of being injured, we considered logistic regression models, where the primary independent measure was participation length—individual measures of interest included age, sex, body mass index, CrossFit affiliation and competition status.

Results

3049 individuals completed the survey (60% completion rate). All competitors, regardless of competition level, had similar incidence of injury (χ²=1.1, p=0.571). For those who reported competing, our calculated injury rate was 0.21–0.54 injuries per 1000 training hours, while for those not competing, the injury rate was calculated as 0.39–1.30 injuries per 1000 training hours. Logistic regression demonstrated short length of participation in CrossFit training as the main factor associated with the odds of being injured (OR=1.82; 95% CI: 1.15 to 2.92). Additionally, training at an official CrossFit affiliate appeared to have a protective effect from injury (OR=0.85; 95% CI: 0.65, 1.10).

Conclusion

Our findings provide evidence of the low risk of injury related to these events. Moreover, these findings support the notion that musculoskeletal injuries may be the result of poor progression plans, which may be minimised by participating in an official CrossFit affiliate.