Relationship between vertical acceleration and autocorrelation function during jumping rope

Jumping Rope (JR) is a consecutive jump exercise and needs upper and lower body movements skills with the rope. JR requires an effective vertical take-off from ground and landing on ground to maintain successive coordination of whole body movements. In this study, we newly developed the index of real-time feedback to improve successive coordination movement using an inertial measurement unit (IMU) during JR movements. 86 elementary-school and junior high-school children participated in this study. They performed basic jump and backward jump for 30 seconds with a IMU on their back. After the measurement, maximum value, root mean square (RMS) value and autocorrelation coefficient from vertical acceleration were calculated to confirm the relationship between vertical acceleration and autocorrelation coefficient during JR. As the results, the maximum value of vertical acceleration had strongly negative correlations with autocorrelation coefficient in basic jump (r > -0.73, p < 0.01). The RMS value of vertical acceleration were moderately related to the autocorrelation coefficient in basic jump (r > -0.50, p < 0.01). According to the result of jump backward, correlations coefficients of both value of vertical acceleration and the autocorrelation coefficient were moderate negative correlations (maximum value: r > -0.51, p < 0.01, RMS value: r > -0.52, p < 0.01).