Population-specific responses to static stretching: lack of acute effects on vertical jump height following high stretching volumes

Over the past two decades, numerous studies have identified a potential negative effect of muscle stretching on sports performance when performed for more than 45–60 s per muscle group. However, the behavior of the muscle-tendon unit in flexible individuals remains untested. Therefore, this study aims to investigate whether habitual stretching, performed by young elite artistic gymnastics athletes for over one minute, affects subsequent performance metrics. Forty-eight Gold-level athletes affiliated with the Italian Gymnastics Federation were recruited. A 5-repetition continuous Countermovement Jump test (CMJ5) was performed before and after static stretching on a contact platform; the outcomes analyzed were jump height, power, reactive strength index (RSI), stiffness, and contact time. Two lower-limb stretching protocols were completed: one with 90-second static holds per muscle group, and one with 60-second holds. In our sample, Wilcoxon signed-rank tests showed no significant pre-post differences after 90 s for any variables. After 60 s, significant reductions were observed in jump height ( p < .001), reactive strength index (RSI; p = .001), and power ( p = .001), but not leg stiffness ( p = .214). Females followed the same pattern for both durations, while males showed no worsening; however, RSI significantly improved after 90 s ( p = .039). The decline in jump height after 60 s was not accompanied by decreases in contact time or leg stiffness, indicating unchanged elastic energy absorption and release capacity. No impairment occurred after 90 s. Overall, these findings mandate the implementation of future research targeting populations with chronic flexibility adaptations to better contextualize the impact of stretching on performance.