# Examining the Link between Isokinetic Strength Metrics and Ball Speed in Women's Soccer  
[PERSON]  
1 Physical Education and Sport Department, Sport Sciences Faculty, Ordu University, Ordu 52200, Tufkiye;  
assessing physical performance [4]. Isokinetic dynamometers are widely recognized as the gold standard for measuring both strength and power [5; 6; 7], making them a common choice in clinical research, particularly in studies related to various health-related injuries and conditions [8; 9]. Therefore, it is crucial to accurately determine the association between sport-specific skills and iso-kinetic force parameters to determine the need for training sports skills using optimal isokinetic exercise protocols. Effectively performing a shot (i.e., kick at the goal) is a critical aspect of soccer for achieving results, and it should be trained using the most suitable training methods [10; 11]. To enhance shot performance, understanding the body biomechanics during a shot and the relationship with the explosive strengthening of relevant extremities and body regions is critical [12]. This approach can improve shot performance, increasing goal success rates and overall match victory probabilities. Effective shot performance by soccer players can significantly affect match outcomes [13; 14]. The amount of force applied to the ball in conjunction with accuracy plays a decisive role in the game, facilitating the creation of goal scoring opportunities that can affect the course of a match [15]. From a biomechanical standpoint, correct ball striking combined with increased applied force accelerates the ball at greater speed. Existing research suggests that isokinetic tests at moderate and high angular velocities are sufficient for monitoring strength training programs in soccer [16]. However, the contradiction arises from that while torque and ball speed in soccer are often positively correlated, only a few cases have statistically significant relationships between them [17]. In contrast, some studies report inconsistent relationships between strength and ball striking speed in soccer [18]. Therefore, the question arises whether isokinetic torques can predict ball speed, a significant determinant of players' overall performance, given that isokinetic tests are considered the gold standard for measuring strength. Thus, the most suitable measurement models for shot performance in soccer have not been fully understood. Consequently, a thorough classification of isokinetic force variables is required. The literature review we conducted showed that limited studies have focused on concentric contractions in the relation between ball speed and knee isokinetic strength. No study has combined both concentric and eccentric contractions, and in this regard, our study aims to fill this significant gap. Studies highlight the reliability of speed data obtained with handheld radar devices, which are frequently utilized in biomechanical research for measuring the velocity of objects [19; 20; 21]. Consequently, the speed at which the ball travels during a shot can be reliably and easily gauged using such equipment [22; 23]. However, one of the primary focuses should also revolve around gaining a comprehensive understanding of the kinetics of ball speed. This understanding can serve as the basis for creating training protocols aimed at enhancing ball speed. Considering that power is the product of strength and speed, it becomes apparent that a greater increase in both speed and strength will lead to superior power augmentation [24; 25]. Moreover, given the positive relationship between speed and strength production in power generation, it becomes imperative to conduct a detailed examination of concentric, eccentric, and isometric forces that could influence ball speed. This research study aims to identify the potential relationships between isometric-, concentric-, and eccentric-contraction-based isokinetic forces and ball velocities generated during shooting in female soccer players competing at a professional level.