# Short vs. Long Bouts of All-Out Rope Skipping: Effects on Metabolic and Perceptual Responses
## 4 Discussion  
This study was the first to compare the metabolic and perceptual responses of apparently healthy young participants to two all-out rope-skipping events, Skip-30 s versus Skip-3 min, and to examine the accuracy of the self-counting function of the adopted E-rope. Our findings showed that Skip-3 min demanded significantly more metabolic and perceptual demands than Skip-30 s, as evidenced by the higher VO\({}_{2}\), average HR during exercise, RPE, and muscle soreness scores at all marked muscle regions. The changes in the VO\({}_{2}\), RER, and HR during both events indicated the dominance of anaerobic metabolism. Our study also found that the E-rope demonstrated from good to excellent reliability as a self-counting tool in both Skip-30 s and Skip-3 min. However, it tended to overestimate the number of skips, with a moderate effect size. The rope-skipping exercises in the present study induced dissimilar responses in the body, compared with earlier study findings on rope skipping and conventional aerobic modalities. Skip-30 s and Skip-3 min were averagely equivalent to 4.79 \(\pm\) 1.01 and 8.00 \(\pm\) 1.26 METs, respectively; consequently, both events can be defined as MVPA (i.e., \(\geq\)3.00 METs) [13; 14]. Collectively, all-out rope skipping can be considered a high-intensity exercise, and it is a mode of exercise that can be easily performed in a self-initiated manner. This simplicity makes it accessible to most individuals and it can be an effective way to achieve high-intensity exercise. However, our study found that when skipping all-out, participants only achieved a submaximal intensity. Therefore, it is unlikely that the training benefits of high-intensity sprinting or cycling could be fully replaced by rope skipping due to the diverse metabolisms elicited by different modes of exercise [28]. In terms of motor competence, previous studies have shown that incorporating submaximal rope skipping (120 skips\(\cdot\)min\({}^{-1}\)) into warm-up routines can improve young soccer players' balance and motor coordination [6]. A five-minute-interval rope-jumping program (100-140 skips\(\cdot\)min\({}^{-1}\) with a work-rest ratio of 30s:30s) has also been shown to be effective in improving endurance runners' jump performance and 3 km running results, and in reducing foot-arch stiffness [8]. Therefore, all-out skipping-specific protocols may have varied benefits for different populations and should be further investigated. Our findings showed that for different exercise durations, a short bout at a higher skipping rate (i.e., Skip-30 s) required less metabolic demands compared to a long bout at a lower skipping rate (i.e., Skip-3 min). This finding contrasts with a previous study [17] that standardized the exercise duration to 5 min at a submaximal intensity and found that a faster skipping rate resulted in higher VO\({}_{2}\). The disparities in findings may be due to differences in the emphasis on the exercise intensity or duration in the respective exercise program. Moreover, the longer exercise duration in Skip-3 min led to a higher peak VO2, which occurred after the cessation of Skip-30 s. This may be related to the short duration of Skip-30 s, during which the VO2 did not have adequate time to reach its peak because of the rest-to-exercise transition. When brief exercise abruptly starts from a resting state, VO2 rises exponentially over time but does not have enough time to stabilize, and so the peak VO2 may only be attained after the end of exercise [29]. Another important finding of our study is that the exercise duration in an all-out manner did not affect the reliance on glycolysis and oxidation pathways in the early phase of exercise (i.e., 30 s). Our results showed that the major energy supply during this period relied heavily on muscle phosphagens and glycogen, as indicated by the RER peaking at 1.07 and 1.15 for all-out Skip-30 s and Skip-3 min, respectively, within the first 10 s after the onset of exercise.