Eccentric external and internal rotation peak torque ratios predict shoulder injuries with national judokas
Darbandi SM, Sebyani M, Behpour S, Behm DG, Hosseinzadeh M. Eccentric external and internal rotation peak torque ratios predict shoulder injuries with national judokas; a prospective cohort study. BMC Sports Sci Med Rehabil. 2025 Jul 15;17(1):201.
ABSTRACT
Introduction and aim: This study aimed to identify isokinetic strength variables of the shoulder rotator muscles that are associated with the risk of upper limb injuries in elite judokas, and to establish predictive cut-off values for injury risk using a prospective cohort design.Study design
Prospective cohort study.Methods: Fifty-three male national team judokas Fifty-three male judokas of the national teams (Mean ± SD, age 18.68 ± 3.08 years, weight 75.34 ± 11.62 kg, height 175.28 ± 7.24 cm) participated in this study. We assessed concentric (CON) and eccentric (ECC) peak torque (PT) values at 60º/s and 300º/s, and the strength status of ER/IR muscles, such as the traditional ipsilateral strength deficit (ER/IR), ER/ER, IR/IR, and the non-dominant (ND) ER/IR: dominant (DOM) ER/IR (ERIR: ERIR), known as the bilateral strength asymmetry. Additionally, we recorded the ratio of Eccentric External (ECC ER) / Concentric Internal rotation (CON IR) before judo activity. The isokinetic Biodex system measured all of the variables. The injury occurrences were recorded during the 10-month follow-up period in the judo national team camps from 2020 to 2021.
Results: We followed fourteen upper limb sport injuries among the 53 judokas. Assessing shoulder rotator muscle strength, particularly in the eccentric mode, played a significant role in shoulder risk factor identification. Significant accuracy of ipsilateral PT deficit ECC ER/IR at (ND) 60º/s (OR 0.973, 95% CI 0.951 to 0.996, p = 0.024), as well as the bilateral PT deficit ECC ERIR: ERIR ratios 60º/s (OR 0.043, 95% CI 0.002 to 0.728, p = 0.029) discriminated between injured and uninjured judokas. The optimal cut-off point of the ND ER/IR ratio associated with the uninjured judokas group was 72.7 (sensitivity, 0.667; specificity, 0.643).
Discussion: The findings of the present study suggest that incorporating pre-participation testing of ipsilateral and bilateral shoulder ER/IR rotator assessment of isokinetic PT, particularly in ECC, can be valuable in an injury prevention program for judokas.
Highlights
Pre-participation testing involving isokinetic peak torque assessment of ipsilateral and bilateral shoulder external/internal rotators, particularly on eccentric strength, can significantly contribute to an effective injury prevention program for judokas. These tests can help identify potential weaknesses or imbalances in the shoulder rotator muscles, allowing for targeted interventions and training strategies to mitigate injury risks.
The findings of this study provide suggestive evidence for the development of a preventive training program that incorporates controlled eccentric exercises specifically tailored for elite judokas. Integrating eccentric training into their regular training regimen may significantly enhance shoulder strength and stability in judokas. This enhancement is expected to decrease the risk of shoulder injuries while simultaneously improving overall judokas performance. Therefore, the implementation of such a program could be a critical component in promoting both injury prevention and performance optimization in this population.
Keywords: Judokas, Shoulder injuries prediction, Strength
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