A method to measure direction change ability at irregular times in juniors

The ability to change direction is important in everyday life for avoiding walking and sports. In actual sporting situations, the ability to change directions at irregular times is required. Previous studies have investigated this using analyses in three-dimensional space and force plate data, but it is preferable to measure it more easily. Furthermore, there is limited understanding of the ability to change direction at irregular times in the junior period. Therefore, the aim of this study was to develop a simple method of measuring the ability to change direction at irregular times in the junior period. The subjects were 44 junior high school students (11.43 ± 1.57 years old, 24 males and 20 females) who were asked to chase a target moving sideways along a 4 m straight line for 6 seconds without being caught. The target was played by two adult males, and the target characteristics were evaluated using approximate entropy (ApEn) to assess the number of turns, maximum speed, and unpredictability. Participants' pursuit accuracy was assessed using the mean and maximum differences, and response latency was assessed using the tau value at which the correlation coefficient was greatest in the cross-correlation analysis. First, to examine the reliability of the measurement method, the intraclass correlation coefficients (ICC1 and ICC1k) were calculated for the characteristics of the experimenter's movements, and significant reliability was confirmed for each variable. When the degree of pursuit was compared between the experimenters, no significant differences were found in the mean difference, maximum difference, or response delay for each variable. These results confirmed that the measurement method developed in this study was reliable, and that there was no effect due to difference between the experimenters. The simple method developed in this study for measuring the ability to change direction at irregular times is expected to be useful in sports and education.