Dataset Information

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

ABSTRACT:

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.

SUBMITTER: Torres-Banduc MA

PROVIDER: S-EPMC8451436 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundCrossFit, a sport and fitness program, has become increasingly popular both nationally and internationally. Researchers have recently identified significant improvements in health and wellness due to CrossFit. However, some individuals assert that CrossFit poses an inherent risk of injury, specifically to the shoulder, due to the intensity of training. Currently, there is limited evidence to support this assertion.HypothesisExercises performed during CrossFit do not place the shoulder at greater risk for injury. Injury rates are comparable to other sports of similar intensity.Study designDescriptive survey study.Level of evidenceLevel 5.MethodsAn electronic survey was developed and dispersed to approximately 980 individuals who trained in CrossFit gyms. The survey identified demographic data, training characteristics, and the prevalence of injury over a 6-month period in individuals who participated in CrossFit training.ResultsA total of 187 (19.1%) individuals completed the survey. Forty-four (23.5%) indicated that they had experienced a shoulder injury during CrossFit training over the previous 6 months. Of those who reported injury, 17 (38.6%) stated that this injury was an exacerbation of a previous injury sustained prior to starting CrossFit. There was no significant relationship between several demographic and training variables and shoulder injury. All shoulder injuries occurred at a rate of 1.94 per 1000 hours training, while "new" shoulder injuries occurred at a rate of 1.18 per 1000 hours training. The most commonly attributed causes of injury were improper form (33.3%) and exacerbation of a previous injury (33.3%). Twenty-five (64.1%) of those who experienced injury reported 1 month or less of training reduction due to the injury.ConclusionShoulder injury rates during CrossFit training are comparable to other methods of recreational exercise.Clinical relevanceClinicians should be aware of training demands of exercises in CrossFit and modifications for these exercises to safely progress their patients back to participation.

Project description:Strengthening the rotator cuff muscles is important for injury prevention and rehabilitation. Since muscle fascicle length improves motor performance and is suggested to reduce the risk of injury for the hamstring, it may be an important variable to promote multidirectional changes in the function and macroscopic structure for the shoulder. Recent literature reviews overwhelmingly suggest that eccentric exercises improve fascicle length and functional measures for the lower limb. However, there is a research gap for the shoulder. Since ultrasound imaging is the most commonly used imaging technique to quantify muscle structure, but has yielded heterogeneous results in different studies, there is another issue and a research gap for the imaging method. Based on the research gaps, the purpose of this study was to evaluate the effects of standardized eccentric strength training on the function and structure of the external rotator cuff muscles using an isokinetic dynamometer and MRI. Therefore, a preliminary pre-post intervention study was conducted and 16 physically active men were recruited in October 2021. For the right shoulder, an eccentric isokinetic training was performed twice a week for almost six weeks. The primary outcome measures (external rotators) were active and passive range of motion, eccentric and concentric torque at 30, 60, and 180°/s isokinetic speed, and fascicle length and fascicle volume for the supraspinatus and infraspinatus muscles. The findings show a training effect for the absolute mean values of eccentric strength (+24%, p = .008). The torque-angle relationship increased, especially in the final phase of range of motion, although a 4% (p = .002) decrease in passive range of motion was found in the stretch test. Positive changes in muscle structure were shown for the supraspinatus muscle fascicle length (+16%, p = .003) and fascicle volume (+19%, p = .002). Based on the study results, we can conclude that eccentric isokinetic training has a significant positive effect on the shoulder. To our knowledge, this is the first eccentric training study using both isokinetic dynamometer and muscle diffusion tensor imaging to access functional and structural changes in the human shoulder rotator cuff muscles. The methods were shown to be applicable for interventional studies. Based on these results, populations such as high-performance handball players with highly trained shoulders should be included in future studies.