# Biomechanics of Punching--The Impact of Effective Mass and Force Transfer on Strike Performance
## 1 Introduction  
Modern combat sports, such as boxing, are characterized by a dynamic combination of physical and technical abilities that determine the effectiveness of strikes. Punching force, as a key factor influencing success in competition, is the result of many variables. One of these is body mass [1]. For this reason, combat sports are divided into weight categories. However, it is often observed that some boxers punch significantly harder than others, even when their body masses are identical. In the boxing community, legends persist about punchers who strike with the power of a heavyweight despite being 20 kg lighter than the limit for that category. What, then, influences the punching force beyond body mass? Genetic predispositions undoubtedly play an essential role [2]. Thick forearm bones predispose an athlete to generate greater punching force. Some studies indicate that genetic predispositions can account for 44% to 68% of phenotypic variability in sports performance, including strength, endurance, and power, which must translate into punching force [3]. Another phenomenon, still relatively underexplored in the context of combat sports, is effective mass. The concept of effective mass in boxing suggests that punching force is not solely a function of an athlete's body mass but also how that mass is utilized during the strike [4]. Effective mass, which describes an athlete's ability to transfer force frombody mass through the kinematic chain, thus becomes a key indicator of the biomechanical efficiency of punching techniques [5]. The analysis of punching force in boxing necessitates consideration of both biomechanical and physiological factors. On the one hand, movement biomechanics play a decisive role in generating maximal punching force [6]. Athletes who effectively engage the muscles of the legs, hips, torso, and arms in the punching motion can generate significant force values, underscoring the critical role of movement coordination and the flexibility of body segments within the kinematic chain [7]. On the other hand, factors such as body mass, the ratio of muscle to fat tissue, and training experience may play a substantial role in maximizing effective mass and punching force [8; 9; 10]. The phenomenon of effective mass is extensively analyzed in the scientific literature. [PERSON] and colleagues [7] defined effective mass as a phenomenon in which the athlete's body mass becomes biomechanically integrated at the moment of contact with the target, leading to the maximization of punching force. This model has been further developed by researchers such as [PERSON] et al. [4] and [PERSON] et al. [11], who proposed various methods for calculating effective mass, including using a modified version of [PERSON]'s formula, where effective mass is calculated as the ratio of maximum punching force to fist acceleration at the moment of contact with the target. Several studies also emphasize the significance of genetic factors in athletes' ability to generate force. Genetic polymorphisms, such as ACTN3 and ACE variants, are associated with muscle performance and the ability to generate dynamic force, which may directly impact effective mass values [2; 3; 12]. Furthermore, the training experience of athletes influences their biomechanical efficiency, as increased years of training allow for better utilization of body mass in generating force [13]. The effective mass of individual strikes is directly related to the punching force generated and the acceleration of the fist [11]. However, while previous studies have explored general punching mechanics and the role of acceleration in strike performance, the relationship between impulse dynamics and effective mass remains underexplored. Most existing research has focused on peak force output or acceleration individually, rather than examining how impulse--the product of force and time--interacts with effective mass transfer in boxing techniques.