## 4 Discussion
In this context, the concept of \"effective mass\" could provide a viable approach to determining a benchmark for assessing the effectiveness of a kick. By focusing on the kinetic aspects of the movement, such as the speed and momentum of the kick in relation to the target, a more consistent and objective measure of performance could be established, potentially offering a more accurate representation of an athlete's skill and effectiveness. The estimated effective mass of the competitors for the side kick was 73%, and for the turning kick, 20% of the total body mass of the competitors. However, this requires confirmation. Our measurements indicate that the analyzed kicks positively correlate with effective mass and force pressure. This is consistent with current knowledge and the available scientific literature on sports and takewon-do, where a relationship has been found in the ability of athletes to increase striking force as a result of increasing body mass [36; 37; 38]. However, it has been noted that beginner competitors mainly use their body mass to generate large striking forces, overestimating its significance [15]. This suggests that the level of athlete advancement may influence the ability to balance the center of gravity and the specific movement technique to achieve greater striking force. Consequently, perhaps the technical skills of competitors could be recognized based on the relationship between kick force and effective mass. Additionally, it has been noted that the starting position and body alignment relative to the target also influence the force of the kick [39], which was not considered in our measurements. In considering the differences between linear and circular motion in martial arts, the distinction between the turning kick and the side kick is crucial. The turning kick involves a whip-like motion with body rotation around the supporting leg, generating force through the rotational action of the core muscles and the kicking leg. For effective force transfer in the sagittal plane of the opponent, a martial artist typically approaches at an angle ranging from 45 to 90 degrees, which affects the possibility of transferring body mass effectively. Conversely, the side kick is characterized by its linear motion and direct approach toward the target, allowing for a more straightforward transfer of body mass towards the opponent or target. However, the choice of technique is not solely determined by force. Technical and tactical considerations, such as the duration of the kick, its executability under specific combat conditions, and the duration of contact with the target, also play significant roles in deciding which technique to employ next. From a utilitarian perspective, this study suggests that the side kick tends to be stronger, utilizing a higher percentage of body mass, and thus requires a lower level of skill for effective execution. This makes it a recommended technique in emergency situations, like breaking through doors or barriers for escape, due to its straightforward application and potent force transfer. Generally, our studies show a correlation between three variables, informing us that a greater effective mass results in greater force pressure and lower foot acceleration. No significant differences were noted between the right and left leg in the average values of force, acceleration, or effective mass while performing both turning kicks and side kicks. Perhaps the effect of lateralization will reveal itself with a larger research group. However, this is consistent with studies showing that, among ITF takewon-do competitors, no significant differences can be observed between maximum speed and movement time during the execution of selected kicks with the right or left leg [40]. It was registered that the foot acceleration was greater for the turning kick. This correlation was also demonstrated by the calculated correlation coefficients. Therefore, it can be assumed that the studied kicks have different kinetic specifics.