Associação da cinemática de membro inferior e da força muscular de tronco e quadril com o desempenho de corredores no star teste modificado

Abstract

The modified Star Excursion Balance Test evaluate athletes dynamic postural control. It has been used in clinical settings as a screening tool to identify athletes at increased risk of injury. The performance in this test requires movement in multiple body joints. In addition, weakness of the trunk and lower limbs muscles may also influence the performance during the modified Star Excursion Balance Test. Therefore, the lower limbs and trunk angular displacement and the lower limbs and trunk strength may influence the athlete performance during the test. This study investigated the relationship between trunk, hip, knee and ankle angular displacement and trunk and hip muscles strength and the performance during the modified Star Excursion Balance Test in runners. Thirty-nine runners participated in this study, 14 women and 25 men, mean age 41.1 ± 9.6 years, body mass 71.2 ± 12.1 kg and height 1.72 ± 0.9 meters. The participants performed the modified Star Excursion Balance Test with the dominant limb as the support limb. A system consisting of Inertial and Magnetic Measurements Units was used to capture the angular displacements of trunk, hip, knee and ankle of the support limb during the test. The software estimated angular position values at maximal reach in each direction of the modified Star Excursion Balance Test. A handheld dynamometer was used to measure the isometric strength of the trunk and hip muscles: extensor and lateral flexor muscles of the trunk, extensors, lateral rotators and hip abductors of the support limb. Two multiple linear regressions were used to assess the association between trunk, hip, knee and ankle angular displacement of the support limb and trunk and hip muscles strength of the support limb and performance during the modified Star Excursion Balance Test. The significance was set at = 0.05. The first regression model revealed that hip and knee angular displacement in the sagittal plane predicted anterior reach and hip angular displacement in the sagittal and frontal planes and ankle angular displacement in the sagittal plane predicted posterolateral reach distance. Specifically, reduced hip flexion and greater knee flexion were associated with greater anterior reach in the modified Star Excursion Balance Test. In addition, greater hip flexion, adduction and greater ankle dorsiflexion were associated with greater posterolateral reach. Muscles isometric torque capacity predicted posteromedial reach, posterolateral reach and composite reach distance during the test. Specifically, strength of the hip extensors was associated with greater posteromedial reach, posterolateral reach and composite reach. In conclusion, hip, knee and ankle kinematics in the sagittal and frontal planes explained 60-65% of the athlete's performance in the modified Star Excursion Balance Test and strength of the extensors hip muscles explained 37-41% of the test performance. These results suggest that clinicians need to perform additional assessment for hip strength and movement and knee and ankle movement in athletes demonstrating poor performance during the modified Star Excursion Balance Test.