The purpose of the present study was to investigate the acute effects of two high-intensity interval training (HIIT) sessions on countermovement jump performance. Twenty-two male regional-level athletes (cyclic, n = 11; acyclic, n = 11) completed two HIIT sessions consisted of multiple running bouts on a treadmill. A different work-interval duration wasapplied in each session. To determine the effect of fatigue on jumping performance, countermovement jump tests were executed pre-effort and at the end of all series. The results showed a decrease in jump performance at the end of the third series respect to the pre-effort condition (p < .001). In addition, the acyclic athletes jumped higher than the cyclic ones (p<.001), revealing a different jumping strategy based on a higher velocity component, and a more efficient elastic energy utilization (p < .01). The neuromuscular mechanisms affected by fatigue, were also different between groups. Inconclusion, during HIIT sessions the neuromuscular status is principally conditioned by the total volume rather than by the work-interval duration, affecting specific performancevariables depending on the sport discipline. The present findings may be useful when conducting HIIT concurrently with other training contents in athletes of both cyclic and acyclic sports.
The purpose of the present study was to investigate the effect of high-intensity interval training (HIIT) on countermovement jump performance. Twenty-two male regional-level athletes (cyclic, n = 11; acyclic, n = 11) completed two HIIT sessions on separate days. A different work-interval duration was applied in each session to determine the short and long protocols. Countermovement jump tests were executed pre-effort and at the end of all series to assess the effect of fatigue on jumping performance. A decrease in jump performance was observed at the end of the third series (p < .001), and different jumping strategies were displayed by cyclic and acyclic athletes, expressed as significant differences in the velocity components, and in the performance outcomes during the braking sub-phase (p < .01). These differences also conditioned the neuromuscular responses to HIIT, affecting specific variables depending on the sport discipline. In conclusion, neuromuscular status was principally affected by the total series completed rather than by the type of protocol implemented. The present findings may be useful when conducting HIIT concurrently with other training contents.