**1. Introduction**

Inter-limb asymmetry has been mostly researched from the aspect of sports injury risk, especially in view of athletes returning to sport after anterior cruciate ligament reconstruction [1–4]. Only recently, the relationship between inter-limb asymmetry and sports performance has been a popular topic of investigation [5,6]. Inter-limb asymmetry is found to be a normal adaptation in many sports that involve unilateral movements (e.g., cricket) [7], but further research in team sports is needed to elucidate whether asymmetries influence performance or injury risk [5,6]. Lately researchers are trying to elucidate whether asymmetries (and which particular type of asymmetry) influence performance [8]. Inter-limb asymmetry may present at the level of di fferent motor abilities (e.g., strength, power, and range of motion) and can be measured locally (e.g., one joint) and globally (e.g., within a complex movement, such as vertical jump). Therefore, various methods have been used for its quantification [9], however, many studies used local knee isokinetic dynamometry [10,11], isometric mid-thigh pull (IMTP) [12,13] or vertical jump tests [14–18]. Further, Sheppard and Young´s [19] model of change of direction (COD) determinants showed that asymmetries could negatively a ffect COD performance. However, supporting evidence is inconsistent.

Two studies investigated the relationship between local inter-limb knee strength asymmetry and performance in COD. Lockie et al. [10] showed mostly positive correlation between di fferent parameters and speed of isokinetic strength asymmetries during knee flexion and extension and T-test performance (*r* = 0.638, 0.669, *p* < 0.01). Exception was one negative correlation (*r* = −568, *p* < 0.01) between peak torque during knee extension (240◦/s) and T-test performance. Similarly, Coratella et al. [11] observed that the same local asymmetries negatively impact COD performance (T-test and 180◦ turn test) (*r* = 0.397–0.614, *p* < 0.05). As the mentioned studies measured local strength asymmetries in the knee joint, they demonstrate the need to study proximal body parts like hip and trunk.

When it comes to the relationship between global asymmetries and performance in COD, results are less consistent. Many studies, using different tests for assessing asymmetries and COD performance, did not detect a relationship between global asymmetries and COD performance. Chiang [12] investigated the relationship between peak torque asymmetry during IMTP and COD ability (assessed as 180◦ turn test) and reported no significant correlation. However, he used bilateral IMTP to quantify asymmetry, which may have influenced methodological validity. While this methodological shortcoming was corrected by Dos Santos et al. [13], who used unilateral IMTP test, they have not found any significant correlation between inter-limb asymmetry in various parameters related to unilateral IMTP and COD performance (*r* ≤ 0.35, *p* ≥ 0.380). Hoffman et al. [14] have not found any significant correlation between asymmetry in single-leg countermovement jump (SLCMJ) height and COD ability (three-cone drill). Although reporting high average asymmetry in jump height and length (up to 10.2%), Lockie et al. [15], have not found any significant correlation between these asymmetries and COD (505 and T-test) performance (*r* = 0.00–0.018, *p* = 0.31–0.99). Similarly, Dos Santos et al. [16] found no significant correlations between asymmetries in horizontal jumping tasks and performance in two COD tasks (*r* ≤ 0.35, *p* > 0.05). Furthermore, Fort-Vanmeerhaeghe et al. [20] have not found a relationship between asymmetry in jump height during SLCMJ and V-cut COD test (*r* = 0.10, *p* > 0.05). Finally, Loturco et al. [18], have found no significant correlation between asymmetries in different parameters during single leg vertical jumps and performance in zig-zag test.

By contrast, few studies have found a significant correlation between global asymmetry in jumping tests and COD performance. Studying female soccer players, Bishop et al. [21] found a significant positive correlation between inter-limb asymmetry in single-leg depth jump height and performance in 505 COD test on left (*r* = 0.66, *p* < 0.01) and right (*r* = 0.52, *p* < 0.05) side. Another study that reported a relationship between asymmetry and performance was of Maloney et al. [22], that explained 63% (*p* < 0.001) of variance of COD performance with leg stiffness and height asymmetry during vertical depth jump.

The reason for inconsistent findings could lay in discrepancies among populations, methods of asymmetry calculation, and COD tests, as well as in low asymmetry values, that are not large enough to influence performance. Taking that into consideration, Sarabon et al. [23] found that explosive strength parameters like rate of torque development (RTD) are more sensitive to detect inter-limb asymmetries compared to maximal strength outcomes like peak force or peak torque during maximal voluntary contractions (MVC), which were used in previous research. Also, local inter-limb asymmetries were assessed only for the knee joint, while proximal regions of hip and trunk were overlooked. Moreover, asymmetries in range of motion were not previously researched in relation to performance. A substantial portion of asymmetry studies was done on amateur athletes and soccer players, which does not give enough insight into the functioning of elite athletes and other team sports, such as basketball. Basketball is characterized by many high intensity changes of direction (COD) [24], indicating that COD ability plays a critical role in basketball performance.

Therefore, the aim of this study is two-fold: (a) to profile elite basketball players in different local strength and range of motion asymmetries of hip and trunk region, and global power asymmetries in horizontal and vertical jumping and (b) to quantify the relationship of those asymmetries with COD performance. We hypothesized that these asymmetries could predict COD performance.

#### **2. Materials and Methods**
