## 1 Introduction  
Agility is a comprehensive skill influenced by various physical, technical, and cognitive factors. In general, agility is defined as the ability to change the direction and speed of movement in response to a stimulus [1]. Its importance in relation to game performance has often been emphasized. It has been identified as a crucial component of player performance in non-invasive team sports such as volleyball [2], handball [3], basketball [4], or soccer [5]. It is a distinctive trait characterized by unique features associated with linear acceleration and speed. In sports games, changes of direction are fundamental, and executing strong and explosive lower body movements is decisive in both offense and defense. During the game, players perform various movements. Some studies have quantified the number and types of movements performed by basketball players, estimated at around 1000 movements in a match, with the majority lasting 3 s or less [6]. More than 40% of movements are forward/backward, and about 20% are lateral movements [7]. Agility is a unique trait associated with linear acceleration and speed [8], reaction time [9], decision-making time, and cognitive processes [10]. Physical determinants of reactive agility with a predominant forward movement and direction changes have been extensively studied and explained [11; 12; 13]. Correlations have been demonstrated between leg explosive strength (\(p\leq 0.05\)) and various change of direction speed tests [14; 15], agility and reactive strength [16], acceleration [17], or speed [18]. It has been concluded that reactive strength and sprint acceleration are important for change of direction speed, but assessed physical properties are not linked to defensive agility performance [19]. Considering the intermittent nature of sports games with frequent transitions between defensive and offensive phases, rest and high-intensity activities, rapid and explosive movements in all directions, acceleration and deceleration [20], and defensive activities can be interpreted as an independent performance factor. Defensive agility is a key element in many sports games [21], especially those involving both individual and team defense, such as basketball [22], soccer or futusal [23], and volleyball [24], and it appears to play a significant role in tennis as well [25]. It refers to a player's ability to move quickly and effectively in the defensive phase, often in response to the opponent's movements or the ball. It involves either a change in speed, a change in direction, or both, always in response to the movements of the attacker [19]. It is reasonable to assume that defensive movements (mainly lateral and backward movements) have different physical and mechanical determinants than forward movements, mainly due to lower production of reaction force, increased torsion moment of knee extensor, respectively, higher speed of hip extension as well as lowering of body center of gravity during lateral movement [26]. To change direction, an athlete must exert force on the ground, and this force must be in the opposite direction of the movement. Therefore, to enhance the ability to change direction quickly, an athlete must maximize their ability to generate lateral forces depending on traction and slope [27]. The identification of lateral force variables in predictive models [28] suggests that the production of lateral reactive force, in addition to vertical force production, is a predictor of lateral jump distance. However, the efficiency of lateral movement is mainly determined by speed and, subsequently, by distance. Previous studies have shown that performance in vertical and lateral tasks occurs independently [29]. In team sports like volleyball, players are frequently required to change direction, speed, and the composition of body segments in response to a game situation with a high cognitive component [30]. This indicates the need to evaluate the level of agility in tests that correspond to game conditions and include a cognitive factor.