Injury risk and injury incidence rates in CrossFit

Lower Body Weightlifting Injuries Treated in United States Emergency Departments from 2012-2021

Weightlifting has become an increasingly popular form of exercise that has been shown to have many health benefits but can be dangerous if performed improperly. The objective of this study was to describe the epidemiology of lower body weightlifting injuries in the United States. The National Electronic Injury Surveillance System database was queried from January 1, 2012, to December 31, 2021, for lower body injuries related to using weightlifting equipment. Demographics, diagnosis, disposition, and mechanism of injury (MOI) were analyzed. There were 7,773 lower extremity weightlifting injuries identified from 2012-2021, giving a national estimate of 311,842 injuries. The most common MOI was dropped weight (n=1785, 22.96%). Deadlifts were the most cited exercise that led to lower extremity injury (n=503, 6.47%). Males were more likely than females to be injured (76% males vs. 24% females; p<0.001), especially by compound movements with free weights including squats (79.63% males vs. 19.96% females, p<0.03) and deadlifts (83.89% males vs. 16.10% females, p<0.001). Nearly all injuries were treated as outpatient but those admitted to the hospital were significantly older than those treated as outpatients (38.0 years vs. 31.2 years, p<0.05). Weightlifting carries a high risk of injury due to the intensity and technique required for the different movements involved.

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®.

Inter-Rater and Test-Retest Reliability of an Innovative Evaluation Tool: CrossFit Functional Assessment Battery of Tests for the Shoulder Joint

Background and objectives This study aims to introduce an innovative functional assessment tool designed for CrossFit athletes, to identify a high risk of injury at the shoulder joint. Additionally, the study seeks to examine both inter-rater reliability, which was tested in 40 CrossFit participants, and test-retest reliability, which was assessed in twenty subjects. Methodology CrossFit Functional Assessment Battery for the Shoulder Joint (CrossFit FABS) is a newly created instrument presented for the first time. The evaluation of the performance of its six items aimed to reveal deficits that could contribute to incidents of shoulder injuries. For this purpose, 40 healthy CrossFit participants were concurrently but independently examined by two raters, and twenty healthy adults active in sports were assessed by the main investigator at two different time points. Cohen's kappa coefficient was used to analyze categorical data with an ordinal structure. Results Inter-rater reliability ranged from 0.824 to 1 (P = 0.000) and test-retest reliability was 0.661 to 0.906 (P < 0.001) for each test of CrossFit FABS. A strong to almost perfect correlation was demonstrated for all the variables between the two examiners. Moderate to almost perfect correlation was shown through test-retest procedures. Conclusions The proposed test battery was established as a reliable tool for evaluating performance routines that represent high injury-risk elements for the shoulder joint in CrossFit athletes.

The effect of blood flow restriction training combined with electrical muscle stimulation on neuromuscular adaptation: a randomized controlled trial

Objective: Low-intensity resistance training (≤25% 1RM) combined with blood flow restriction training (BFRT) is beneficial to increasing muscle mass and muscle strength, but it cannot produce increased muscle activation and neuromuscular adaptation, as traditional high-intensity strength training does. The purpose of this study is to investigate the effects of independently applying BFRT and electrical muscle stimulation (EMS), as well as combining the two methods, on muscle function. Methods: Forty healthy participants with irregular exercise experiences were randomly assigned to four groups: BFRT-alone group (BFRT, n = 10), EMS-alone group (EMS, n = 10), BFRT combined with EMS group (CMB, n = 10), and the control group (CTR, n = 10). All participants received low-intensity squat training at a load of 25% 1RM 5 times/week for 6 weeks. Cross-sectional area (CSA) and electromyographic root mean square (RMS) in the rectus femoris, as well as peak torque (PT) of the knee extensor, were measured before and following a 6-week intervention. Results: Following the 6-week intervention, the increases in muscle activation in the CMB group were statistically higher than those in the BFRT group (p < 0.001), but not different from those in the EMS group (p = 0.986). Conclusion: These data suggest that the combination of BFRT and EMS for low-intensity squat training improved the muscle strength of the lower limbs by promoting muscle hypertrophy and improving muscle activation, likely because such a combination compensates for the limitations and deficiencies of the two intervention methods when applied alone.

Using Wearable Inertial Sensors to Monitor Effectiveness of Different Types of Customized Orthoses during CrossFit® Training

BACKGROUND

Dynamic balance plays a key role in high-impact sports, such as CrossFit, where athletes are required to maintain balance in various weightlifting exercises. The loss of balance in these sport-specific movements may not only affect athlete performance, but also increase the risk of injuries.

OBJECTIVES

The aim of the study is to achieve greater insight into the balance and athlete position during the CrossFit training by means of inertial sensors, with a particular focus on the role of different custom foot orthoses (CFOs) in order to detect correlations with the role of the cavus foot.

METHODS

A total of 42 CrossFit^® athletes, aged 25 to 42 years, were enrolled in this study. One-way ANOVA tests with post-hoc analysis of variance were used to compare foot posture groups and effects of different types of customized foot orthoses.

RESULTS

When comparing the effects of CFOs with the respective balance basal level during the pistol squat exercise, we observed a significant (p = 0.0001) decrease in the sway area, antero-posterior displacement (APD) and medio-lateral displacement (MLD) compared to the basal using both types of CFOs.

CONCLUSION

No significant positive effects of CFOs were observed in some static tests. On the contrary, positive effects of CFOs and, in particular, postural insoles, are relevant to dynamic balance.

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.

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.

A Study on the Incidence of Hand or Wrist Injuries in CrossFit Athletes

Purpose

The purpose of this study was to investigate the reported rates and characteristics of injuries among CrossFit athletes with specific attention to the hand and wrist. We further sought to identify trends and associations of these injuries by examining demographic data.

Methods

A questionnaire was created to capture self-reported information on the incidence of hand or wrist injuries and their associations in CrossFit athletes. It was distributed between April 2020 and July 2020 to athletes training at CrossFit affiliated gyms in the New York and Pennsylvania regions. Bivariate logistic regression analysis was used to identify factors correlated with an injury.

Results

A total of 270 responses (97.5% response rate) were available for final analysis. The median age of respondents was 34 years and 72.2% had been participating in CrossFit for at least two years. CrossFit athletes reported injury rates of 62.2% while engaged in CrossFit training and 20.4% reported an injury specific to the hand or wrist. The majority of hand or wrist injuries occurred after one year of CrossFit training (65.4%). The majority of reported initial injuries occurred to the wrist (75.4%); subsequently, 29.1% reported reinjuring the same region. While 58.2% reported not yet having healed or taking longer than one month to feel fully healed, 72.8% reported returning to unmodified training within one month. Only 15 respondents reported seeking medical attention from a physician for their injury. Physicians generally recommended a training break of over one month, but only two patients reported taking a break this long. Male sex and length of participation in CrossFit were associated with an increased risk of developing a hand or wrist injury.

Discussion

Hand and wrist injuries represent a significant proportion of injuries among CrossFit athletes. CrossFit practitioners are potentially returning to unmodified training too early following injury, leaving them susceptible to further injury. Physicians and therapists must consider these findings and address both therapies and preventative measures for these types of injuries with their patients.

Soft Tissue Mobilization and Stretching for Shoulder in CrossFitters: A Randomized Pilot Study

Background. The shoulder in CrossFit should have a balance between mobility and stability. Glenohumeral internal rotation deficit and posterior shoulder stiffness are risk factors for overhead shoulder injury. Objective. To determine the effectiveness of instrument-assisted soft tissue mobilization and horizontal adduction stretch in CrossFit practitioners’ shoulders. Methods: Twenty-one regular CrossFitters were allocated to experimental (stretching with isometric contraction and instrument-assisted soft tissue mobilization) or control groups (instrument-assisted soft tissue mobilization). Each session lasted 5 min, 2 days a week, over a period of 4 weeks. Shoulder internal rotation and horizontal adduction (digital inclinometer), as well as posterior shoulder stretch perception (Park scale), were evaluated. Shapiro–Wilk test was used to analyze the distribution of the sample. Parametric Student’s t-test was used to obtain the intragroup differences. The inter- and intra-rater differences were calculated using a repeated measures analysis of variance (ANOVA). Results. Average age was 30.81 years (SD: 5.35), with an average height of 178 (SD: 7.93) cm and average weight of 82.69 (SD: 10.82) kg. Changes were found in the experimental group following intervention (p < 0.05), and when comparing baseline and follow-up assessments (p < 0.05) in all variables. Significant differences were found in the control group following intervention (p < 0.05), in right horizontal adduction and left internal rotation. When comparing the perception of internal rotation and horizontal adduction in both groups, significant differences were found. Conclusions. Instrument-assisted soft tissue mobilization can improve shoulder horizontal adduction and internal rotation. An instrument-assisted soft tissue mobilization technique yields the same results alone as those achieved in combination with post-isometric stretch with shoulder adduction.