The Effect of a Single Bout of Chinese Archery on Core Executive Functions in Preadolescent Children in Shanghai

Background: Recent literature has demonstrated that acute physical activity benefits the transfer of executive functions. However, further studies indicated the type of variability in the effect of physical activity on executive functions. Therefore, this study initially explored the effect of a single bout of Chinese archery on subdomains of core EFs in preadolescent children; Method: Eligible participants were allocated either an intervention group (n = 36) or a control group (n = 36). The subjects in the intervention group received a 45-min Chinese archery session. The primary outcomes were the performance of core EFs (inhibition control, working memory, and cognitive flexibility) in preadolescent children, assessed with psychological paradigms (Fish Flanker Task, N-Back Task, and DCCS (Border version), respectively). Paired t-test and ANCOVA were used to analyze the mean difference in the performance of core EFs within and between subjects, respectively; Results: Considering reaction time and accuracy, we explored the impressive performance in three cognitive tasks with acute Chinese archery; Conclusion: The finding suggests that a single bout of Chinese archery benefited three subdomains of core EFs in healthy preadolescent children.


Introduction
An emerging body of evidence has verified the positive association of executive functions (EFs) induced by physical activity programs throughout one's lifespan [1][2][3][4][5][6]. EFs involve those cognitive processes that underlie goal-directed behavior and are coordinated by activity within the prefrontal cortex [7][8][9]. EFs vitally influence individuals throughout their lifespans in areas such as mental and physical health [10], academic achievements [11], career success [12], and social and psychological development [13]. Generally, It is accepted that core EFs are composed of inhibition control, working memory, and cognitive flexibility [8].
Although most studies in this area have emphasized chronic physical activity program engagement, there is an emerging body of research on EFs following a single bout of physical activity program [3,[14][15][16]. Conclusively, a single bout of physical activity program positively influences EFs [17][18][19]. The Stroop task has verified the most significant enhancement (ES: 0.2-1.16) of inhibition control following acute physical activity program [20]. However, there is less literature and evidence regarding the positive effect on working memory and cognitive flexibility.
Furthermore, there is limited knowledge on how to impact core EFs with acute physical activity program cessation across one's lifespan [21]. Yet, most literature has highlighted young adults and elderly populations, with less research on other diverse subpopulations across their lifespans [22]. Importantly, this is a well-developed period for core EFs, which are sensitive to physical activity during childhood [8]. Meanwhile,

Participants
All participants were recruited from those students in 4th grade in the Songjiang Experimental School Affiliated with Shanghai University of International Business and Economics (SUIBE) in Shanghai, China. The inclusion criteria in this study are right-hand dominant, regular physical fitness and health conditions, age ranges from 9 to 11 years, and no history of neurological and psychiatric disease.
Eventually, 72 inclusive participants were allocated either an active control group (n = 36) or an interventional group (n = 36) based on intention. The Declaration of Helsinki conducted this study with the approval of the ethics review committee for research at Chulalongkorn University (Protocol NO. 073. 1/64). All participants and their parents were informed and assigned consent before participation.

Experimental Design
The study incorporates three sessions with different periods (Figure 1). Firstly, during the screening session (t0), demographic data were collected. Using a between-subjects pretest posttest comparison design, all eligible subjects were assigned to receive either intervention group or active control group. Secondly, all subjects completed the core EFs performance assessment as pretest (t1) before treatment. Thirdly, after a 45-min treatment period, posttest (t2) was conducted in both groups. Core EFs performance assessment includes inhibition control, working memory, and cognitive flexibility. Subjects in the intervention group performed Chinese archery practice. The subjects in the active control group performed regular extracurricular activities. Figure 1. Experimental design. The study included three sessions (t0, t1, and t2) and two groups: an intervention group (n = 36) and an active control group (n = 36). The experimental group performed Chinese archery practice while the active control group was a regular extracurricular activity. The main outcome variables were core executive functions performance.

Measurements
Demographic data were collected from the physical fitness assessment database in school in the current semester.

Core Executive Functions
Three computer-based neuropsychological paradigms (Fish flanker task [52], N-Back test [53], and DCCS (Border version) [54] were applied to evaluate the performance of Figure 1. Experimental design. The study included three sessions (t 0 , t 1 , and t 2 ) and two groups: an intervention group (n = 36) and an active control group (n = 36). The experimental group performed Chinese archery practice while the active control group was a regular extracurricular activity. The main outcome variables were core executive functions performance.

Measurements
Demographic data were collected from the physical fitness assessment database in school in the current semester.
Core Executive Functions Three computer-based neuropsychological paradigms (Fish flanker task [52], N-Back test [53], and DCCS (Border version) [54] were applied to evaluate the performance of inhibition control, working memory, and cognitive flexibility, respectively. E-prime software 2.0 (Psychology Software Tools Inc., Pittsburgh, PA, USA) carried out the relevant paradigms test and data collection. All assessments were performed in the quiet computer room. After the intervention activity, all subjects were required to return to the same computer room within 10 min and complete the same cognitive task assessments after a few minutes of rest. The reaction times of correct responses and the accuracy were collected as the evaluation index of core EFs performance.

Inhibition Control
The Fish Flanker task was applied to evaluate the inhibition control of participants [3,55]. Material: Two different trial types were presented, congruent and incongruent. In each trial, subjects tried to offer fast and accurate responses when determining the direction of the center fish. In congruent trials, all five fish in the stimulus array were revealed to be facing the same direction. In incongruent trials, the four distracting fish were indicated in the opposite direction of the central target fish. Regarding size, each fish stimulus was displayed as 3 cm tall and separated by 1 cm or a visual angle of 1.72 • . The target fish was always located in the exact location in every trial. The stimuli were presented for 1.5 s until a response was for each trial. A new trial was presented after an interval ("+" with blue background) of 0.5 s.
Procedure: Before each formal trial, each block of practice trials (12 congruent trials and 12 incongruent trials) was conducted to ensure sufficient accuracy for all participants. Formal trials consisted of 48 congruent trials and 48 incongruent trials, respectively, followed by 1-min intervals between 2 block trials. All trial types were randomly presented with equal probability.

Working Memory
The N-back task (n = 1, 2) in this study was used to evaluate the working memory performance of participants.
Materials: Two different conditions (n back, n = 1, 2) were performed, and each condition was presented in a fixed order for all participants. Six different shapes with various colors (green circle, red line, blue cross, purple star, brown square, and orange triangle) were displayed focally in an assigned manner. The figure of shapes was a height of 3 cm. Each trial was presented for 2.9 s on a black background, then 3 s with a fixed inter-stimulus.
Procedure: All participants were administered to respond (L button press meant the same matching target. Otherwise, the A button press was determined) whether the present stimulus matched the previous shape displayed n (n = 1, 2 in the present study) steps before the target in a sequence of shape stimuli. During the task, all participants were demonstrated to respond via visual stimuli as fast and accurately as possible with an assigned button (L or A). Formal trials consisted of 2 condition block trials (24 1-back trials and 24 2-back trials), followed by a 1-min interval between 2 block trials. Before each formal trial, each block of training trials (10 1-back trials and 10 2-back trials) was conducted to ensure sufficient accuracy for all participants during the formal experiment.

Cognitive Flexibility
DCCS (Border version) was implemented to assess participants' cognitive flexibility in the present study. The target cards of various colors (blue and red) and shapes (boat and rabbit) were utilized in the DCCS (Border version).
Materials: Three different trial types were presented: in color trials, the participants were required to sort test cards according to color; in shape trials, the shape was the cue of sorting test cards; and in border trials, if the black border test cards were displayed, color trials were executed. Otherwise, the shape trials had to be conducted. Participants were required to pass the color trials, shape trials, and border trials in turn. The stimuli of the DCCS (Border version) were 5 cm tall and 9 cm wide target cards (rabbit and boat with bivalent color). Each trial started when a 3-s stimulus was presented on a black background, followed by a fixed intertrial interval of 2.5 s.
Procedure: All subjects should try to give fast and accurate responses when visual stimuli are presented on the screen. For smooth operation during the trials, each phase of practice trials (8 color trials, 8 shape trials, and 12 border trials) was given. In turn, participants completed three blocks of heterogeneous trials (16 color trials, 16 shape trials, and 32 border trials). Each block test followed a 1-min interval. During the trials, stimuli switches were presented randomly, ensuring that the same target card could not be displayed on the screen sequentially.

Experimental Procedure
All participants attended extracurricular activities at Songjiang Experimental School Affiliated to SUIBE, with a 45-min session each. The two extracurricular activities conducted concurrently after the scheduled classes.
In the intervention group, the children were instructed to practice Chinese archery by coach, who is extensively experienced with teaching diverse subpopulations and contexts. All children had received five sessions of Chinese archery and met the basic requirements, including the primary technique, traditional etiquette, mind regulation skills, and historic and cultural features. All participants had a week interval before treatment condition. The Chinese archery was in a dedicated outdoor venue. The contents of the intervention program included techniques (standing posture, setting arrow, pushing and pulling the string, lifting the bow, drawing a full bow, collimation, shot, closing form, etc.), mind training (self-reflection, self-regulation, concentration, deep-breathing techniques, etc), and basic etiquette (pre-etiquette, post-etiquette, etiquette to target).
An intervention session comprised of a warm-up section (5 min of stretching and 3 min of mind conditioning), a Chinese archery section (about 34 min), and an end section (2 min of meditation and 1-min-deep breathing).
While treatment starts, participants line up and must be taken up bow and arrow with a peaceful mind and posture erect, then fully concentrate on shooting process. Simultaneously, the central theme of the indoctrination from Chinese archery is that it is not principally concerned with scoring hits but with a circle of practice. The exercise session followed the principle of Chinese archery. The whole intervention process is completed under the control and guidance of the coach.
As an active control group, the children in control group participated in regular extracurricular activities scheduled by school in the real world. In this session, children were required to walk on the track for 10 min and spent the rest of the time doing homework together in the classroom.

Statistical Analysis
All statistical analyses were conducted using SPSS 25 (IBM Corp., Armonk, NY, USA). Demographic, anthropometric, and physical fitness variables between groups were analyzed using independent samples t-test and Chi-squared test. Paired t-tests were conducted to investigate the statistical difference in reaction time and accuracy (N-back task, fish Flanker task, DCCS task) in each group on core executive function. Considering the purpose of increasing statistical power and reducing potential bias owing to the baseline imbalance, ANCOVA was used to analyze the significant difference in reaction time and accuracy from relevant assessment (N-back task, fish Flanker task, DCCS task) between groups, pre-test performance as covariates and post-test performance as the dependent variable. The estimated effect size was presented as partial eta square (η 2 ). p < 0.05 was set as statistical significance.

Demographic Data
The independent samples t-test and Chi-squared test revealed the detailed descriptive statistics of demographic, anthropometric, and aerobic fitness data for the subjects in Table 1.
The outcomes showed that the height of subjects reached a considerable difference between groups (t = −2.19, p < 0.05).

Core Executive Functions Performance
The detailed descriptive statistics of EFs are displayed in Table 2. Table 2. Performance from subcomponents of core executive function, data presented as mean (SD).  Figure 2a). Similarly, a statistical difference (t = 3.50, p = 0.00) was also detected in the control group with pre-test (542.61 ± 91.90) milliseconds compared to post-test (504.31 ± 63.28) milliseconds (Figure 2a). In contrast, there was no significance in incongruent trials in both groups.
(a) (b) Figure 3. The performance of inhibition control within and between subjects. (a) the mean difference in accuracy of congruent trials; (b) the mean difference in accuracy of incongruent trials. Note, * present p < 0.05, within subjects and # present p < 0.05, between subjects, respectively. The data are presented as the mean ± SD.
Meanwhile, ANCOVA found significant differences in border trials (F (1,36) = 13.4, p= 0.00, η 2 = 0.16) between groups; the intervention group showed higher accuracy ( Figure   Figure 7. The performance of cognitive flexibility within and between subjects. (a) the mean difference in reaction time of border trials; (b) the mean difference in accuracy of border trials. Note, * present p < 0.05, within subjects and # present p < 0.05, between subjects, respectively. The data are presented as the mean ± SD.

Discussion
This study intends to explore the influence in subdomains performance of core EFs after a single bout of Chinese archery in preadolescent children. Subsequently, our results support the hypotheses that a single bout of Chinese archery significantly improves preadolescent children's inhibition control, working memory, and cognitive flexibility. Specifically, the considerably faster response reaction time was confirmed in congruent trials, 2-back trials, and border trials within and between subjects. In addition, regarding accuracy, the impressive higher in congruent and incongruent trials, 2-back trials, and border trials were consistently detected within and between subjects.
Over the last decade, investigations into the transient effect of a single bout of physical activity have been mainly focused on the inhibitory control subdomain of core EFs, with a prominent 41% of the published studies [14]. Commonly, the outcomes have supported that an single bout of moderate-intensity [56] or HIIT [28,57] physical activity positively impacts inhibitory control in children regardless of the assessment task employed. For example, Hillman et al. [3] declared that a single 20-min bout of moderate-intensity aerobic exercise improves performance in incongruent trials in healthy preadolescents. Likewise, Cooper et al. [58] observed a significant effect on response times of the simple Stroop test (R: 818 ± 33 ms, E: 772 ± 26 ms; p = 0.03) and the complex level of the Stroop test (R: 1095 ± 36 ms, E: 1043 ± 37 ms; p = 0.04) in 44 adolescents (12 ± 0.6 year) following 10 min high-intensity sprint-based exercise. Consequently, a small-to-moderate effect size is found regarding the effect of a single bout of moderate-intensity physical activity on inhibitory control in healthy preadolescents (6-12 years) [Hedges' g = 0.28; CI: 0.01, 0.56; p = 0.04] [59]; similar conclusions on HiiT physical activity are supported [60,61]. Our outcome in the current study is consistent with previous literature.
Compared with inhibition control, there is increasing attention being paid to demonstrating the effect of a single bout of physical activity on working memory performance [16,26,62,63] and cognitive flexibility performance [26,41,64,65] in the preadolescent subpopulation. Specifically, Ishihara et al. [66] announced that working memory and inhibitory control achieved the best benefit after 50-min game-based tennis lessons compared to techniquebased lessons and watching TV. Using a between-subjects pretest-post-test design, working memory and inhibitory control were assessed after 15 min of intervention. Additionally, Chen et al. [15] initially reported the impressive benefits of a 30-min group jog at moderate intensity on inhibition, working memory, and the shifting of EFs in healthy preadolescent children (n = 83, F = 42, M = 41). Using a within-between subjects' pretest-post-test design, three subdomains of core EFs were evaluated after 20-25 min of treatment.
Given the characteristics of Chinese archery, it appears to possess at least three advantages that enhance EFs in the present study. Firstly, it aims to reduce stress and foster mind-body unity to encourage positive moods and relaxed brain states. EFs rely on the prefrontal cortex and other neural regions, which become the most vulnerable with excess dopamine when suffering from negative emotion (e.g., stress, sadness, loneliness) [76,77]. Conversely, the reduction of stress [78,79] and positive mood [80] contribute to the enhancement of EFs. Bigelow et al. [81] illustrate that a 10-min session of mindfulness meditation displays a premium improvement (d = 0.55-0.86) of all executive function tasks (Stroop Task, TMT-B, and Leiter-3) compared to 10 min of exercise with a within-subjects pretestpost-test design in children (n = 16, Mean age = 11.38 (±1.5)) with ADHD. During the practice of Chinese archery, participants must fully concentrate on motor coordination and breathing rhythm in a calm and relaxed mood. The state facilitates the arousal of the mind-body unity state as soon as possible. It produces a simultaneous concentrated, relaxed state of the brain, which promotes executive function performance [34].
Secondly, over-competition in sports can destroy self-esteem and character development. Participants during Chinese archery practice must take up the bow and arrow with a peaceful mind, erect posture, and a fully concentrated shooting process [82]. Chinese archery is not principally concerned with scoring hits because participants are not matched in their strengths. Those participants are required to highlight comparing one's past and peer interaction instead of scoring hits [47]. This process produces less aggression and anxiety. Conversely, more self-esteem is achieved. The effect facilitates the cultivation of introspection, self-regulation, and character development of individuals than competitive sports [47].
Thirdly, the key to physical activity-induced benefits of EFs is that the diverse and continuous challenges of EFs are addressed in the real world [66]. Indeed, the exerciseinduced transfer of EFs might be determined by the complex, controlled, and adaptive cognition and movement of the degree addressed in exercise [68]. During Chinese archery performance, participants would be confronted with the diverse situations in the real world. Those conditions push participants to continuously challenge various executive skills [82] that are conducive to improving executive function.
For instance, participants must bear complex motor sequences and discipline in mind, inhibit attending to distractions, and concentrate on every motor action during the process. Meanwhile, cognitive flexibility is also challenged; participants would constantly adjust their targeting actions and timing of shooting arrows based on their experience and prediction of unexpected changes in a natural setting.
The exercise protocol in the present study utilized the real world with ecological validity, which is based on extracurricular activities (ECA) in school, rather than most of the investigations being conducted in the laboratory with treadmills or cycle ergometers [14]. Additionally, ECA in school provides children with more opportunities for social interaction and a better motivational climate. With growing concerns about the younger generation's health, ECA-based programs in school have several critical advantages (e.g., economy, convenience, breadth, diversity, and accessibility). Importantly, this study not only objectively proves that Chinese archery significantly improves core EFs in adolescent children but also further extend current knowledge how physical activities are the most effective way to enhance executive function [83]. Furthermore, the encouraging finding provides a highly potential application in public health promotion in normal preadolescent children and education practice on a large scale.
There are several limitations to this study. First, the randomized trial was not conducted in the present study but was a quasi-experimental design. Therefore, it is possible to produce more bias in the results of this study. Therefore, it is necessary to consider future research involving a randomized controlled study design to reduce bias. Second, an objective measure of physical activity during intervention is missing. Regarding the role of intensity as moderator [24], it is acceptable to monitor the heart rate range in real-time during the intervention and collect data as a subjective index for all participants in the future. Third, although the real-world interventional setting is regarded as a strength in this study, it also inevitably increased other confounders. This study detected an impressive result in the benefit of inhibitory control, working memory and cognitive flexibility performance. However, the long-term effects of this physical activity program and the sustainability of its benefit remain unknown. Further investigations are valuable. Finally, the adolescent subpopulations with EF deficiencies or disorders merit further investigations in the future.

Conclusions
To the best of our knowledge, the current study is the first to experimentally examine the effect of Chinese archery on core EFs in preadolescent children. This study supports that a single bout of Chinese archery positively impacted core EFs in preadolescent children. Furthermore, compared with the control group, shorter reaction time and higher accuracy of subcomponents of core executive functions in the Chinese archery group were significantly detected. it indicates an encouraging application for improving core executive functions with Chinese archery practice in normal preadolescent children in large-scale educational setting.  Informed Consent Statement: All participants and their parents were informed and assigned consent before participation.