Isokinetic assessment of swimmers' shoulders: benefits and limitations, magnitude and direction asymmetries and, network analysis

Abstract

This thesis was divided into three studies, which aimed to: a) indicate the benefits and limitations of isokinetic test results for the performance of the main shoulder joint movements in swimmers, considering the different competitive levels, swimming techniques, race distances and gender; b) compare the magnitude and determine the consistency of isokinetic peak torque asymmetries between the angular velocities of 60 and 180°/s in the shoulder joint movements of internal and external rotation, flexion and extension; c) to investigate the complex and simultaneous relationships between the World Aquatic points (performance) and the parameters of the isokinetic test (peak torque and total work) of the shoulder movements of internal and external rotation, flexion and extension, by means of a network analysis, and to compare the peak torque and total work between the preferred and non-preferred sides of the shoulders of competitive swimmers. For the first objective (study 1), a systematic review study was carried out, following the PRISMA recommendations. To determine the magnitude and consistency of the direction of isokinetic peak torque asymmetries (study 2), 21 competitive crawl swimmers were evaluated, in which the isokinetic torques of internal and external rotation, flexion and extension of the shoulders obtained by the isokinetic dynamometer were analyzed. In study 3, 23 competitive male swimmers took part and the networks formed to analyze the multiple relationships used the World Aquatic points (performance variable), peak torque and total work of the internal and external rotation movements, shoulder flexion and extension at a speed of 180°/s. Statistical analyses used in the study were: study 2 - The Shapiro-Wilk test was used for normality, the T-test for dependent samples was used to compare the magnitude of the asymmetries between the speeds of 60 and 180°/s and the Kappa coefficient was used to determine the consistency of the asymmetries between the speeds of 60 and 180°/s; study 3: The automatic learning network analysis technique was used to investigate the simultaneous relationships between the World Aquatic points and peak torque values and total work of the internal and external rotation, flexion and extension movements and the isokinetic parameters between the preferred and non-preferred upper limbs were compared using the t-test for dependent samples. A significance level of 5% (p < 0.05) was considered in all tests. The results of study 1 indicated that the main benefits of shoulder isokinetic analysis in swimmers are in clinical research and relationships with swimming performance, and the main limitations are in the positioning of the swimmer on the equipment. In study 2, the results showed greater magnitude of asymmetries in internal rotation (p = 0.007; ES: -1.38 to -0.13) and flexion (p = 0.008; ES: -1.30 to -0.06) performed at 60°/s. The levels of agreement in the direction of the asymmetries between the angular velocities were reasonable to substantial (Kappa: 0.40 to 0.69). For study 3, we identified through network analysis that the non-preferred limb showed complex relationships between the study variables and in the comparison, the total external rotation work was greater (p = 0.028; ES = -0.24) for the preferred side. From the systematic review it can be concluded that the use of the isokinetic dynamometer makes it possible to check the levels of strength, endurance, balance ratio and asymmetries between swimmers of different techniques, helping to analyze and monitor the clinical conditions of swimmers' shoulder joints. Regarding the comparison of the magnitude and determination of asymmetries (study 2), it can be concluded that understanding muscle asymmetries allows the development of specific training programs to correct strength imbalances and optimize swimming techniques. For study 3, the application of force on the non-preferred side, due to the swimmer's individual difficulties, seems to represent a window to increase swimming performance. The results found can help researchers, coaches and athletes make decisions on the choice of assessments and the individualization of the results found. This information is crucial for the quality and interpretation of the tests, as well as helping swimmers to determine the clinical condition of the shoulder and levels of asymmetry.