## 3 Results  
### Included Studies  
Keyword searches of five electronic databases (see Section 2.1 above) initially identified 3064 potential articles. An additional five records were identified by examining references in the most relevant studies. After eliminating duplicate or irrelevant articles, 70 studies were obtained. Two authors ([PERSON] and [PERSON]) jointly analyzed the selected articles. After excluding articles that did not meet our screening criteria, a total of 19 studies, including 15 cross-sectional studies [4; 40; 25; 41; 42; 20; 43; 44; 45; 46; 47; 48; 49; 50; 51] and 4 intervention studies [21; 23; 24; 52] were selected for the analysis. The cross-sectional studies and intervention studies were analyzed separately. Characteristics of both sets of studies are summarized in Table 1; Table 2, respectively. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Study** & **Country** & **Sample Size** & **Mean** & **Measurement Tool** & **Cognitive Functions** & **OSE** & **CSE** & **Exercise** \\
**(First Author, Year)** & **Country** & **OSE/CSE** & **Age (y)** & **Measurement Tool** & **Cognitive Functions** & **Activities** & **Activities** & **Activities** & **Experience** \\ \hline \hline Ciglia, 2011 & IT & 12/10 & 23.38 & Line-length judgment task & Visuospatial attention & Volleyball & Rowing & CSE: \(3.4\pm 1.0\) kJ/day \\  & & & & & & & & CSE: \(3.1\pm 0.5\) kJ/day \\ \hline \hline \multirow{2}{*}{Dai, 2013} & \multirow{2}{*}{CN} & \multirow{2}{*}{16/16} & \multirow{2}{*}{68.73} & Task-switching paradigm & & & & Table tennis/tennis: & \(13.0\pm 5.7\) y \\  & & & & & & & & Jogging/swimming \\  & & & & & & & & \(11.1\pm 4.5\) y \\  & & & & & & & & \(0.7\pm 0.6\) y \\ \hline \hline [PERSON], 2013a & CN & 20/20 & 20.13 & Stop-signal task & Inhibition & Tennis & Swimming & Temis: \(5.5\pm 2.8\) y \\  & & & & & & & Swimming: \(4.9\pm 1.7\) y \\ \hline [PERSON], 2013b & CN & 14/14 & 20.4 & Go/no-go task & Inhibition & Tennis & Swimming & Temis: \(3.1\) y \\ \hline \hline [PERSON], 2014 & CN & 20/20 & 69.43 & [PERSON] flanker task & Inhibition & Table tennis, tennis, & Jogging, & OSE group: \(7.8\pm 1.1\) y \\  & & & & & & badminiton, etc. & swimming, etc. & CSE group: \(6.7\pm 2.4\) y \\ \hline \hline \multirow{2}{*}{[PERSON] and [PERSON], 2014} & \multirow{2}{*}{US} & \multirow{2}{*}{22/17} & \multirow{2}{*}{20.13} & D-KETS lower test, & Problem-solving, & & & \\  & & & D-KETS color-word & decision-making, & & & & \\  & & & & & & & \\  & & & & & & & \\  & & & & & & & \\  & & & & & & & \\  & & & & & & & \\  & & & & & & & \\ \hline [PERSON] and [PERSON], 2015 & CN & 21/22 & 65.11 & Task-switching & Cognitive flexibility & Badminton or table & Jogging & Exercise group: \(2\)30 min/session, \(2\)30\%, \(\geq\)230\%, \(\geq\)230\%, \(\geq\)230\%, \(\geq\)230\%, \(\geq\)230\%, \(\geq\)230\%/y \\ \hline \hline \multirow{2}{*}{[PERSON], 2016} & \multirow{2}{*}{CN} & \multirow{2}{*}{36/38} & \multirow{2}{*}{67.06} & \multirow{2}{*}{
\begin{tabular}{} \end{tabular} } & Visuospatial working memory & Table tennis & Jogging or swimming & Exercise group: \(2\)30 min/session, \(2\)30\%, \(\geq\)230\%, \(\geq\)230\%, \(\geq\)130\%/y \\ \hline [PERSON], 2016 & CN & 20/20 & 65.53 & Visuospatial attention & Visuospatial attention & Badminton or table tennis & Jogging & Exercise group: \(2\)30 min/session, \(2\)30\%, \(\geq\)230\%, \(\geq\)230\%, \(\geq\)230\%/y \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Characteristics of the cross-sectional studies that were examined. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Study** & **Country** & **Sample Size** & **Mean** & **Measurement Tool** & **Cognitive Functions** & **OSE** & **CSE** & **Exercise** \\