## 4 Discussion  
This study aimed to examine the effect of an 8-week coordinative tennis exercise training on the updating aspect of the working memory (WM) performance in young children in both behavioral and neurophysiological domains. The behavioral results showed that the hit rate of performing the 1-back task by the experimental group increased after the intervention. At the same time, the experimental group gained a smaller percentage of false alarms after the exercise, but neither the hit rate nor the false alarm rate changed much in the control group. Both the experimental group and the control group gained faster RT after the exercise, and the improvement was more significant in the experimental group than it was in the control group. These findings suggest that the eight-week tennis game program facilitated improvement in the updating function of the WM. The result is consistent with that of prior research examining the relationship between physical exercise and WM of adolescents and adults. [PERSON] et al. (2018) used the Sternberg task to examine working memory maintenance. During this task, the adolescents were called upon to remember a set of letters and indicate whether a probe matches one of the previous memory set items. It was concluded that performing a combination of aerobic and coordinative exercises daily elicits benefits for WM maintenance of adolescents aged 12-15 years. [PERSON] et al. (2018) utilized a letter digit span task to measure WM capacity, and they underwent the WM task before and after an afterschool coordinative exercise regimen. The study suggested that WM capacity of the 9- to 10-year-old children benefited from the coordinative exercise program. [PERSON] et al. (2018) reported that acute, intermediate-intensity exercises have a strong beneficial effect on the speed of response in \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Time Segments**} & \multicolumn{2}{c}{**Time Segments**} & \multicolumn{2}{c}{**Time Segments**} \\  & \multicolumn{2}{c}{**1**} & \multicolumn{2}{c}{**2**} & \multicolumn{2}{c}{**3**} & \multicolumn{2}{c}{**4**} \\ \cline{2-9}  & **Pre-Test** & **Post-Test** & **Pre-Test** & **Post-Test** & **Pre-Test** & **Post-Test** & **Pre-Test** & **Post-Test** \\ \hline \multirow{2}{*}{**Experimental group**} & \(-0.08\) & \(0.29\) & \(0.05\) & \(0.43\) & \(-0.21\) & \(0.12\) & \(0.20\) & \(0.24\) \\  & (0.05) & (0.07) & (0.11) & (0.09) & (0.06) & (0.10) & (0.11) & (0.10) \\ \hline \multirow{2}{*}{**Control group**} & \(0.07\) & \(0.09\) & \(0.18\) & \(0.14\) & \(0.08\) & \(0.04\) & \(0.12\) & \(0.02\) \\  & (0.05) & (0.06) & (0.10) & (0.09) & (0.06) & (0.09) & (0.10) & (0.10) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The values of oxy-Hb for each of the four 90 s time segments in the 1-back task, M (SD). the WM tasks in adults. Moreover, the result is similar to those of studies investigating the effect of acute exercises on the executive function in normal children [43]. To our knowledge, much of the literature on the relationship between exercise and working memory pays particular attention to the aerobic exercise and the capacity or maintenance of WM. There is a relatively small body of literature that is concerned with the coordinative exercise and updating function of WM. In addition, only few empirical studies investigated the issue in preschool children. The present findings may add some evidence to the exercise-related WM improvement in young children. However, these findings are contrary to that of [PERSON] et al. [44], who found no evidence for a longitudinal additive effect of sequential physical and spatial training on cognitive performance. A possible explanation for this contrary finding might be that they used an intelligence structure test to assess the cognitive performance associated with the hippocampus, and the participants in that research were young, homogeneously well-educated adults.