## 4 Discussion
### Reactive Strength and Power Output Performance  
Both fast- and moderate-velocity flywheel training significantly enhanced participants' reactive strength, average output power, and vertical jump height. In contrast, the slow-velocity condition did not elicit substantial improvements. These findings confirm the efficacy of flywheel resistance training in improving lower-limb explosive performance, especially in tasks dominated by the stretch-shortening cycle (SSC), where high-velocity loading produced more pronounced responses. Regarding reactive strength, the greatest improvements were observed in the fast-velocity condition, indicating that rapid eccentric-concentric transitions effectively activate the neuromuscular system and improve jump efficiency within short ground contact times. [PERSON] et al. found that an eight-week flywheel squat training program significantly enhanced the reactive strength index, jump performance, and stretch-shortening cycle function in collegiate basketball players, confirming the effectiveness of flywheel-based eccentric overload for improving reactive capabilities [45]. Similarly, [PERSON] et al. demonstrated that flywheel training led to greater improvements in countermovement jump height and eccentric utilization ratio compared to eccentric overload training, suggesting enhanced stretch-shortening cycle efficiency and reactive strength in explosive tasks [46]. In terms of average output power, both fast and moderate conditions yielded significant improvements, particularly between 4 and 8 min post-intervention. This enhancement may stem from central neural activation, improved muscular coordination, and better control of metabolic by-products under high-intensity loading. [PERSON] et al. also emphasized that real-time adjustment of training intensity based on movement velocity is a key determinant of explosive performance gains in resistance training [47]. [PERSON] et al. demonstrated that angular acceleration measured in real-time during flywheel exercises is highly sensitive to fatigue, providing a useful metric for monitoring training load and managing fatigue to maintain power output [48]. Vertical jump height, a classic marker of neuromuscular performance and SSC function, was significantly improved in the fast condition in this study, with the highest gains observed 8 min post-training. [PERSON] and [PERSON] reported that flywheel half-squat training offers substantial benefits for vertical jump performance, particularly through improvements in ground reaction force and take-off velocity [49]. Likewise, [PERSON] and [PERSON] identified training level, load, recovery, and contraction type as key modulators of PAP effectiveness in explosive tasks such as jumping and sprinting [50]. At the mechanistic level, improvements in these neuromuscular performance indicators can be attributed to several factors. First, the eccentric overload inherent in flywheel training elicits greater neuromuscular responses compared to traditional resistance training, potentially contributing to improved force transmission and movement efficiency [51]. Second, high-velocity flywheel loading has been shown to improve maximal strength and power performance, which may be partially explained by enhanced neuromuscular activation [52]. Third, post-activation performance enhancement induced by flywheel training may involve increased neuromuscular efficiency and potentiation mechanisms that facilitate improved performance in ballistic tasks [53]. It is worth noting that although the slow-velocity condition involved substantial eccentric loading, the lack of a sufficient velocity stimulus may have resulted in inadequate neural activation, delayed SSC responsiveness, or even the suppression of PAP.