## 4 Discussion
It is plausible that hopping, even at maximal frequency, may not sufficiently challenge leg stiffness capacity in females, whereas in more demanding tasks such as landing, they might not be able to produce the same relative leg stiffness as males. However, it is important to note that the protocols used in the study conducted by [PERSON] and [PERSON] [38] did not standardize the landing height, which could have potentially rendered the task incomparable between females and males [40]. In accordance with the previous results for the K\({}_{\text{MEAN}}\) variable, the same pattern emerged for K\({}_{\text{BEST}}\). The non-significant differences for testing time can be attributed to the specific methodology used in the study, i.e., the Superjump(r) workout. Considering that K\({}_{\text{BEST}}\) is a derivative of K\({}_{\text{MEAN}}\), it follows similar principles in assessing pyometricperformance. The results showing no significant differences in testing time can be expected, as the pyometric training effect is primarily associated with the subjects' capacity to generate power during explosive movements and not their ability to sustain the performance over time. When a muscle-tendon unit is repeatedly exposed to increased mechanical loading, muscle strength gains are observed, which is accompanied by an increase in tendon stiffness. Previous research [41; 42] has fully investigated the assessment of both tendon stiffness and lower body strength performance, emphasizing the efficacy of mini trampoline training. However, [PERSON] et al. [23] stated in their work that it is not clear whether the cause of the sex difference in leg stiffness is due to the physical characteristics (i.e., height and weight) of male and female subjects. Furthermore, hopping involves the storage and utilization of strain energy and, therefore, the maintenance of leg stiffness; landing involves the dissipation of strain energy and, therefore, a rapid reduction in leg stiffness following the initial impact phase. Nevertheless, in our results, men still had higher leg stiffness than women. Our findings reinforce the importance of leg stiffness assessment when evaluating the effects of pyometric training. The use of repeated jumps on the mini trampoline allows for a comprehensive analysis of lower limb mechanics, which provide valuable insights into the subjects' pyometric abilities. Moreover, the similarity in outcomes between \(\mathrm{K}_{\mathrm{MEAN}}\) and \(\mathrm{K}_{\mathrm{BEST}}\) supports the notion that \(\mathrm{K}_{\mathrm{BEST}}\) is a suitable derivative for evaluating pyometric performance in the context of our study. However, the effects of pyometric training on stiffness are unclear, as some studies have found no significant changes in tendon stiffness after pyometric training, while other studies have found significant increases that show improvements in the force transmission to the bone [43]. Significant differences in testing time emerged for \(\mathrm{R}_{\mathrm{P}}\) with decreases in values after the Superjump(r) training session. This can be attributed to the fact that, in line with the existing literature, pyometric training has a notable impact on the \(\mathrm{R}_{\mathrm{P}}\) of the subjects. \(\mathrm{R}_{\mathrm{P}}\) is the ability of the musculotendinous unit to produce a powerful concentric contraction after a rapid eccentric contraction [44]. Because \(\mathrm{Superjump}^{\mathrm{\textregistered}}\) training includes quick and powerful jumping to activate the elastic properties of the major leg muscles, it might have contributed to the decrease, increasing the accumulation of muscular fatigue. It is well-known that pyometric exercise can lead to a temporary reduction in the torque-generating capacity of muscles, which could explain the observed decrease in \(\mathrm{R}_{\mathrm{P}}\) values in the participants after the Superjump(r) training session [45]. Additionally, pyometric exercises, such as those performed on the mini trampoline, can induce micro-muscular lesions.