## 4 Discussion
In weightlifting, athletes perform fast eccentric squats to place their bodies under the barbell during the snatch and clean and jerk, which may lead to a significant increase in VL fascicle length, as previously described [31]. Weightlifters constantly perform these fast eccentric squats with maximum loads during training and sometimes with super-maximum loads during competitions (>100% of 1-RM). These findings should be interpreted with caution, as other neuromuscular factors, such as the percentage of type II muscle fibres, may also differentiate the two groups. Lean mass is a significant contributor to performance in both weightlifting and throwing events [14; 24]. In our study, weightlifters were found to have lower trunk lean mass compared to throwers, although no significant difference was observed with respect total, legs and arms lean mass. Generally, weightlifters focus on increasing lower body lean mass, mainly because lower body mass/strength is essential for an elevated performance. On the contrary, throwers aim to increase whole-body lean mass. Similarly, no significant difference was found for LMI between weightlifters and throwers. Previous studies showed that LMI can predict performance in elite powerlifters [40]. Likewise, in the current study, LMI was significantly correlated with performance in snatch and back squat. Thus, LMI may be a useful index for predicting performance in power sports, such as weightlifting and track and field throwing and to evaluate training-induced adaptations following long-term training programs. Finally, no significant difference was found for VL muscle thickness and fascicle angle. A previous study of power athletes revealed that athletes with higher lean mass had also higher VL muscle thickness and fascicle angle compared to power athletes with lower lean mass [37]. However, this finding was not supported by the current study, as no significant difference was observed for total lean mass between athletes. As expected, 1-RM strength in snatch and back squat was significantly greater for weightlifters compared to throwers. This result may have resulted from the higher technical level and experience of weightlifters in snatch and back squat. Furthermore, weightlifters use high training loads (>85% of 1-RM) during their year-round training, compared to throwers, who train with both light and heavy resistance loads [8]. An interesting finding is that VL fascicle length was significantly positively correlated with 1-RM strength in snatch and back squat. Snatch is a high-velocity, high-load, full-body exercise whereby athletes apply their force rapidly [41], whereas back squat is a low-velocity, high-load exercise, although athletes apply their force with maximum intentional movement velocity [42]. Hence, power-trained athletes with longer VL fascicle length may perform better in 1-RM snatch and back squat. In addition, RFD was also correlated with 1-RM strength. Although throwers had lower 1-RM strength, recent studies have shown that snatch and back squat may be significant determinants for competitive track and field throwing performance, meaning that as 1-RM strength increases, track and field throwing performance also increases [2; 7]. In support of the current results, previous studies of weightlifters and throwers showed significant positive correlations between RFD and 1-RM strength [6; 24]. This study is subject to some limitations. No neural analysis or muscle biopsies were evaluated, both of which could have provided improved insight into the nature of the results. Athletes were measured one week after the main national competition; therefore, these differences may not be applicable during other training periods (i.e., specific preparation etc.). Another limitation is the small sample size in each group of athletes, although the elite level of the athletes used in the current study may counterbalance this particular limitation. Differences were found only for male athletes; therefore, more research is needed for female athletes.