A022: Effects of Interval Rope-Skipping on Physical Fitness of MiddleSchool Students

<bold>Background:</bold> Physical fitness is a reliable indicator to measure one's ability to perform physical activity and exercise and is a determinant of health status. The purpose of this study was to examine the effects of interval rope-skipping on the physical fitness in middle school students aged 12 to 14 years old. <bold>Method:</bold> A total of 147 students (12.8 ± 0.5 years; 72 females) participated in the 8-week school intervention program (25 min/session, 3 sessions/week). Participants were assigned to three interval rope-skipping groups with different work-to-rest ratios (WRR): Intervention group 1 (IG1, n = 49, WRR = 1.0), Intervention group 2 (IG 2, n = 49, WRR = 0.7), and Intervention group 3 (IG 3, n = 49, WRR = 1.5). In this study, we assessed the subjects' physical fitness in terms of body composition, cardiorespiratory fitness, and muscular strength the day before and the day after the intervention. Paired t-tests and one-way analysis of variance (ANOVA) with Bonferroni post hoc analyses were performed. <bold>Results:</bold> After the intervention, when compared with baseline values, all three groups significantly improved the maximal oxygen uptake, grip strength, standing long jump, and sit-ups (p &lt; 0.05). Additionally, the 50-metre sprint test was significantly improved in the IG1 (p &lt; 0.05) and the IG2 (p &lt; 0.01), but not in the IG3. The inter-group comparison results showed that the greatest improvement in maximal oxygen uptake and 50-metre sprint test in IG2 (2.89 ± 1.54 mL·kg−1·min−1 and -0.47 ± 0.30 s), which was significantly higher than in IG1 (1.98 ± 1.52 mL·kg−1·min−1 and -0.19 ± 0.46 s, p &lt; 0.05) and IG3 (1.70 ± 1.15 mL·kg−1·min−1 and -0.13 ± 0.47 s, p &lt; 0.05). However, no significant changes in other body composition parameters were observed, except for body mass index in IG2 ( -0.11 ± 0.28 kg/m², p &lt; 0.05) and body fat in IG1 ( -0.30 ± 0.78 kg, p &lt; 0.05). <bold>Conclusion:</bold> This study demonstrated that 8 weeks of interval rope-skipping improved the physical fitness of middle school students. The effectiveness of exercise interventions may be affected by the work-to-rest ratio as an important moderating variable. Notably, interval rope-skipping with a work-to-rest ratio of 0.7 may be the most beneficial for improving the physical fitness of middle school students.