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

From Sweat to Strain: An Epidemiological Analysis of Training-Related Injuries in CrossFit®

Purpose

This study aims to conduct an epidemiological investigation into the types and causes of injuries during CrossFit® training in Germany.

Patients and Methods

Voluntary athletes from various German CrossFit® gyms participated, providing personal information, training habits, and details on injuries through a standardized questionnaire.

Results

The study involved 308 participants, with an equal sex split, a peak age of 20-40, and a BMI of 24.3 ± 3.3 kg/m2. Most participants trained for over two years (49.4%), primarily in supervised groups. Motivations for engaging in CrossFit® included health prevention (33.1%), athletic training (32.8%), and work-life balance support (17%). Injuries were reported by 28.6% of participants, with 61.4% experiencing single injuries. The majority of injuries (55.3%) occurred during the middle of workouts. Injury types included wounds (23.3%), contusions, sprains, or strains (cumulative 30.8%), and fractures (2.9%). Almost all injured individuals (96.5%) had a time-loss injury, with a return to sport ranging from a day to over three months. Treatments varied, with 50.6% not requiring medical intervention, 34.1% undergoing physiotherapy, 21.2% receiving medication and 8.2% needing surgery. Barbell exercises, notably Snatch and Clean, were main exercises with association to injuries, accounting for 36.3%. The Box Jump stood out as the exercise with the highest isolated injury prevalence (14.3%). Notable injury causes included falls during Pull-Ups and lumbar disc herniation linked to Deadlifts. Following injuries, 45.8% of participants made training adjustments.

Conclusion

This study provides an epidemiological investigation into the types and causes of injuries during CrossFit® training in Germany. The shoulder and knee joint exhibited the highest injury prevalence. Barbell exercises, box jumps, and bar pull-ups were identified as major exercises with association to injuries. Prevention through technical training and the incorporation of soft boxes could reduce the risk of injuries in CrossFit®.

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.

Epidemiological Profile among Greek CrossFit Practitioners

CrossFit (CF) is a popular and rapidly expanding training program in Greece and worldwide. However, there is a lack of scientific evidence on the risk of musculoskeletal injuries related to CF in the Greek population. A self-administered survey of 1224 Greek CF practitioners aged 18 to 59 was conducted and analyzed using the Statistical Package for Social Sciences (SPSS) software. The highest percentage of the participants (34%) practiced 5 days per week for 60 min (42.2%) and had 2 days per week of rest (41.7%). A total of 273 individuals (23%) participated in CF competitions and 948 (77%) did not. The results showed that the most common injuries were muscle injuries (51.3%), followed by tendinopathies (49.6%) and joint injuries (26.6%). The shoulders (56.6%; n = 303), knees (31.8%; n = 170), and lumbar spine (33.1%; n = 177) were the most commonly injured locations. The logistic regression model showed that participation in competitions (p = 0.001), rest per week (p = 0.01), duration of training per session (p = 0.001), and frequency of training per week (p = 0.03) were statistically significant factors for injury. Training level was not a statistically significant factor for injury (p = 0.43). As CF continues to gain popularity on a global scale and the number of athletes gradually increases, it is important to monitor the safety of practitioners. Clinicians should consider participation in competitions, rest, training duration, and frequency in order to make CF safer.

Risk Factors for Injury in CrossFit®-A Retrospective Analysis

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.

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.

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.

Supraspinatus repair and biceps tenodesis in competitive CrossFit athletes allow for a 100% of return to sport

PURPOSE

The shoulder is the most commonly injured body part in CrossFit training. The aim of this study is to report the clinical and MRI results of an arthroscopic repair of supraspinatus tear associated with SLAP lesion in competitive CrossFit athletes.

METHODS

Competitive CrossFit athletes affected by a full-thickness supraspinatus tear associated with SLAP lesion secondary to training injury were prospectively enrolled in the study. Clinical diagnosis was confirmed with MRI (> 1.5 T). Functional evaluation was done using the Constant Score (CS) and ASES score (ASES). All lesions were treated with single-row repair and biceps tenodesis. Minimum follow-up (clinical, MRI) was 24 months.

RESULTS

Nineteen patients were available at the final follow-up. The average age was 43-year-old (range 28-52, SD 8), 12 were males and 7 females. Pre-operative CS and ASES were 67 (range 61-77, SD 7) and 71 (range 62-79, SD 5), respectively. At the 24-month follow-up, 19/19 athletes resumed intensive training and 17/19 returned to competitions. CS and ASES rose to 90 (p = 0.039) and 93 (p = 0.04), respectively. At the final follow-up, MRI indicated complete healing of the tendon in 15 (79%) cases and 4 (21%) cases with type II Sugaya repair integrity. Two of the patients of the latter group did not return to their usual training level and showed type II (Kibler) scapular dyskinesis.

CONCLUSIONS

Arthroscopic repair of the supraspinatus tendon associated with biceps tenodesis led to a 100% of return-to-CrossFit training and 90% rate of individuals resuming competitions at 24 months of follow-up. MRI showed 15 (79%) cases of complete healing and 4 (21%) cases with type II Sugaya repair integrity; biceps tenodesis clinically failed only in 1 case and the athlete complained of a decrease in the competitions scores and opted to discontinue CrossFit competitions.

LEVEL OF EVIDENCE

IV.

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.