摘要：Background and Study Aim: Boxing bouts are explosive by nature as they include components of speed and power in order to be effective. If a boxer cannot produce power, his performance will be limited. This was the paramount motivation to perform a study on the evolution of the gripping strength in both hands as an indirect indicator of upper limb strength, since this is a major factor in the medical control of boxing matches. Material and Methods: 22 Mexican high performance fighters were studied by body weight divisions (lightweight, middleweight and heavyweight) and their strength was assessed by training phase (general, special and competitive). The Relative Strength Index was also assessed, since it took body weight into consideration, thus assisting us to medically control training in this sport, a matter on which there is little reference in the literature. For the statistic analysis a student t test was conducted to evaluate the variables of right hand strength as compared to the left hand’s, as well as to the remaining variables by training phases. Moreover, we conducted a Variance Analysis (ANOVA) in order to ascertain if there was a statistical difference between divisions concerning all the variables studied. Results: Values found in hand-grip strength in both hands were lower than those reported for elite boxers internationally. We also ascertained a mathematical statistically non-significant increase in hand-grip strength in both hands across the entire sample, for which we recommend improving strength training in upper limbs. There was a mathematical increase with a significant statistic difference for most of the variables studied in the middleweight division by training phase, proving that these boxers were better trained concerning their upper limb strength. Conclusions: There was also a mathematical increase with significant statistic difference for the overall boxer group studied by phases in regard to the Right Relative Strength Index. We recommend it as a suitable indicator for controlling strength in boxers
