Effects of Jump Rope Exercise on Stretch-Shortening Cycle Ability in Elementary School Students

Abstract

PURPOSE: Not much research has investigated how jump rope exercise can lead to improvements in physical abilities, including stretch-shortening cycle (SSC) ability, in children. This study examined whether the maximum number of jumps elementary school students could perform in a jump rope exercise (“max jump count”: MJC below) was associated with their jumping performance, short-distance sprint performance, and other fitness indicators, as well as whether a jump rope training program led to improvements in those abilities. METHODS: Seventy-four elementary school students (34 boys, 40 girls) aged from 6 to 12 years old participated in this study (mean height: 138+11 cm, mean weight: 33+8 kg). In addition to MJC, all students were assessed in terms of 20-m sprint time (ST), rebound jump index (RJI), vertical jump (VJ), and grip strength (GS). For RJI, students were measured with an optical measurement system as they performed five consecutive rebound jumps with both legs: RJI was calculated as jump height divided by ground contact time. Pearson’s product-moment correlation coefficients (r) were determined to check for associations between MJC and the other fitness indicators. The training effects of jump rope exercise were investigated by comparing students’ performance before and after completing four weeks of training. Students were allowed to decide for themselves how often to jump rope during these four weeks. RESULTS: Before training, students achieved a mean MJC of 93+98 jumps, with a range of 2-459 jumps. A negative correlation was observed between MJC in before training and ST (r=-0.46, p<0.01). Additionally, positive correlations were observed between it and RJI (r=0.57, p<0.01), VJ (r=0.33, p<0.01) and GS (left-hand: r=0.31, p<0.01; right hand: r=0.34, p<0.01). Four weeks of training resulted in significant improvements in MJC (+43%, p<0.001), RJI (+7%, p<0.05), and VJ (+5%, p<0.01). However, jump rope exercise frequency did not result in any apparent differences in training effects. CONCLUSIONS: These results suggest that MJC was associated with a variety of physical abilities in elementary school students. However, it could not be clearly demonstrated that jump rope training improve performance indicators related to SSC ability in elementary school students.