## 1 Introduction
Resistance exercises can be classified either into unilateral or bilateral movements [16; 17]. BIL exercises involve both limbs simultaneously, inducing the same type of muscle contraction, e.g., squats, deadlifts, etc. The first aspect, according to many authors, which proves the general applicability of BIL exercises, especially those such as the squat and deadlift is their biomechanical structure, which is similar to activities such as jumping and short-distance sprinting [18; 19; 20; 21]. In addition, BIL training is commonly recommended in many resistance training programs because it allows for significant mechanical overload of the contractile apparatus, as it is possible to use a much higher external load than during UNI training [20; 22]. The ability to use a significant external load improves the neuromuscular mechanisms involved in generating force and power and is an extremely important variable of BIL exercise. It must be underlined that the highest threshold motor units are recruited only in maximal or near-maximal contractions. Additionally, some authors suggest that when they are developed in similar kinetics, the transfer of increased recruitment of high-threshold motor units is more effective in terms of sports performance [23; 24; 25]. Therefore, training sessions using BIL exercises have been used in the periodization of strength and power training for many years. UNI exercises, on the other hand, are being increasingly applied in resistance training, where they no longer play the role of complementary exercises, but form the foundation of a given resistance training program [15; 16]. Therefore, UNI exercises are predominant for specific activities like jumps, sprints, and changes of direction [26; 27; 28]. Therefore, UNI exercises are currently not used as accessory exercises in soccer and other team sports such as basketball or handball, but are often the basis for periodization of strength training, using the ability to transfer force and power to one limb. This allows moving in many directions, which is an obvious advantage due to the demands of team sports games [29; 30]. In soccer, it will be decisive, especially in such technical activities as dribbling, winning a running duel, taking the ball away from the opponent, or performing an agility move that ends with a strike at the goal [31]. An additional attribute of the use of UNI exercises is the analysis of match units using GPS systems (Catapult) considering such variables as accelerations and decelerations. The high pace of the game is based on the holistic use of the musculoskeletal system, where, on one hand, the same muscle groups are involved in the performance of a given motor task, and on the other hand, they also perform a stabilizing function. A good example has been shown in defensive activities which require players to actively engage in regaining the possession of the ball, reduce space and block forward passes, demanding high-intensity actions such as accelerations and decelerations [32]. These actions are often initiated by the movements of the opposing team and are thus high-speed reactions (acceleration and deceleration) to put immediate pressure on the ball. In the offensive zone (the opposition half) it is essential to press high, as nearly half of all winning ball turnovers in various European leagues are shown to create scoring opportunities. This is why the periodization of resistance training based on the use of UNI and BIL exercises is important because it allows the use of appropriate training measures depending on the period of the macrocycle that the team is in. For example, consider that a team plays 3 games in 12 days, taking into account that soccer players can cover from 9 to 14 km during a match and perform a distance of 0.7-3.9 km of fast running (>20-25 km/h), 0.2-0.6 km sprinting (>25 km/h), and approximately 600 accelerations and decelerations. Recovery times may be too short during crowded professional soccer matches when it comes to maintaining physical fitness and preventing injuries [33; 34; 35].